Inactivation effect and kinetic analysis of multi-band ultraviolet LED combined with Ag/N modified magnetic TiO2 on microorganisms in ballast water

doi:10.1016/j.jwpe.2023.104751

Journal of Water Process Engineering

Volume 58, February 2024, 104751

https://doi.org/10.1016/j.jwpe.2023.104751 Get rights and content 获取权利和内容

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Highlights 突出

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UVA/UVC_LED+Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalytic technology can effectively remove harmful aquatic microorganisms in ballast water.
UVA/UVC_LED+Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化技术可有效去除压载水中有害的水生微生物。
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When the modification ratio is 1.5% Ag/3% N, the photocatalyst has the best performance and the best inactivation effect on harmful microorganisms in ballast water.
当改性比例为 1.5% Ag/3% N 时，光催化剂对压载水中有害微生物的性能最佳，灭活效果最好。
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The Biphasic model is the most suitable model for the actual situation of multi-band ultraviolet photocatalytic inactivation.
Biphasic 模型是最适合多波段紫外光催化灭活实际情况的模型。

Abstract 抽象

The invasion of harmful aquatic organisms from ship ballast water is a serious threat to the marine ecosystem. However, the existing treatment technology has the defects of high energy consumption, secondary pollution and easy revival of organisms, etc. How to inactivate the microorganisms in ballast water efficiently is always a difficult challenge. In this study, the inactivation of Karenia mikimotoi and Escherichia coli under UVA/UVC_LED photocatalytic system (UVA/UVC_LED + Ag/N-Fe₃O₄-SiO₂-TiO₂) was investigated using Ag-modified and N-modified magnetic TiO₂ nanomaterials. The results showed that the ability of 1.5 % Ag with 3 % N dual-modified TiO₂ to enhance the system's biologically logarithmic inactivation rate was 4–5 times higher than that of conventional unmodified TiO₂. The Ag/N-modified magnetic TiO₂ had the best photocatalytic activity at a dosage of 500 mg/L. After 6 cycles of use, the inactivation efficiency in combination with UVA/UVC_LED only decreased by 8.76 % compared with the initial use, and the recycling rate was still up to 95.75 %. Meanwhile, the scanning electron microscope showed that the photocatalyst itself only had some minor changes after 6 cycles, which confirmed the fact that the photocatalytic removal rate (higher than 91.24 %) could still be maintained at a high level. The UVA/UVC_LED photocatalytic system significantly inhibited the scavenging ability of superoxide dismutase (SOD) on reactive oxygen species (ROS), enhanced the toxic effect of ROS on cells, and ultimately accelerated the process of apoptosis and inhibited biological resurrection. In addition, this study verified the inactivation kinetics of the target microorganisms using Chick-Watson, Hom and Biphasic models, and found that all individuals in the same population differed in their tolerance to UV radiation, and some of them absorbed more than a threshold dose of UV radiation before showing inactivation responses. The Biphasic model (R²: 0.99571–0.99926) can better simulate the nonlinear changes exhibited during the inactivation process and is more applicable to the actual disinfection situation of UVA/UVC_LED photocatalytic systems. The UVA/UVC_LED + Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalytic technology developed in this study, as a novel oxidation process, reduces energy consumption while effectively inhibiting the reanimation of organisms, and exhibits a strong potential for application in the fields of restoring the environment of water bodies and blocking the spread of pathogens.
有害水生生物从船舶压载水中入侵，对海洋生态系统构成严重威胁。但现有的处理技术存在能耗高、二次污染、生物体易复活等缺陷。如何有效地灭活压载水中的微生物始终是一项艰巨的挑战。在本研究中，使用 Ag 改性和 N 改性磁性 TiO₂ 纳米材料研究了 UVA/UVC LED 光催化体系（UVA/UVC LED + Ag/N-Fe 3 O_4-SiO _2-TiO 2）对 Karenia mikimoto 和大肠杆菌的灭活。结果表明，1.5 % Ag 和 3 % N 双重改性 TiO₂ 提高系统生物对数灭活率的能力比传统未改性 TiO₂ 高 4-5 倍。Ag/N 改性磁性 TiO₂ 在 500 mg/L 的剂量下具有最佳的光催化活性。使用 6 次循环后，与 UVA/UVC_LED 联合使用的灭活效率与初次使用相比仅下降了 8.76 %，回收率仍高达 95.75 %。同时，扫描电子显微镜显示，光催化剂本身在 6 次循环后仅有一些微小的变化，证实了光催化去除率（高于 91.24 %）仍能维持在较高水平的事实。 UVA/UVC_LED 光催化系统显著抑制超氧化物歧化酶（SOD）对活性氧（ROS）的清除能力，增强 ROS 对细胞的毒性作用，最终加速细胞凋亡进程，抑制生物复活。此外，本研究使用 Chick-Watson、Hom 和 Biphasic 模型验证了目标微生物的灭活动力学，发现同一种群中的所有个体对紫外线辐射的耐受性不同，其中一些个体在表现出灭活反应之前吸收了超过阈值剂量的紫外线辐射。双相模型（R²： 0.99571–0.99926）能较好地模拟灭活过程中表现出的非线性变化，更适用于 UVA/UVC_LED 光催化系统的实际消毒情况。本研究开发的 UVA/UVC_LED + Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化技术，作为一种新型氧化工艺，在降低能耗的同时有效抑制生物体的复活，在恢复水体环境和阻止病原体传播领域表现出强大的应用潜力。

Keywords 关键字

Ballast water

TiO₂

压载水

TiO₂

Microbial inactivation

Kinetics

UV LED

微生物灭活

动力学

UV LED

1. Introduction 1. 引言

While ballast water ensures the safety of ship navigation, it also carries a large number of harmful marine microorganisms that are highly adaptable [1,2]. Non-native species (bacteria, viruses, zooplankton, etc.) transferred through ballast water can cause serious damage to the marine ecosystem, which has been listed as one of the four major risks endangering the safety of the global marine environment [3]. In order to meet the microbial concentration requirements in ballast water stipulated by the International Maritime Organization (IMO) (Table 1) and to effectively curb the invasion of foreign organisms in ballast water, the search for safe, efficient, economically reliable treatment methods without secondary pollution has become the focus and hot spot of domestic and international research.
压载水在保证船舶航行安全的同时，也携带了大量适应性强的有害海洋微生物 [1,2 ]。通过压载水转移的非本地物种（细菌、病毒、浮游动物等）会对海洋生态系统造成严重破坏，已被列为危害全球海洋环境安全的四大风险之一 [3]。为了满足国际海事组织（IMO）规定的压载水中微生物浓度要求（表 1），有效遏制外来生物对压载水的入侵，寻找安全、高效、经济可靠且无二次污染的处理方法已成为国内外研究的重点和热点。

Table 1. D-2 guideline emission limits for living organisms.
表 1.D-2 生物体排放限值指南。

Type of microorganism 微生物类型	Emission limit value 发射限值
>50 μm plankton >50 μm 浮游生物	<10 per/m³ <10 ^每平方米
≤50 μm and ≥ 10 μm plankton ≤50 μm 和 ≥ 10 μm 浮游生物	<10 per/mL <10 个/mL
Escherichia coli 大肠杆菌	<250 CFU/100 mL <250 CFU/100 毫升
Enterococcus 肠球菌	<100 CFU/100 mL <100 CFU/100 毫升
Vibrio cholerae (O1 and O139) 霍乱弧菌（O1 和 O139）	<1 CFU/100 mL <1 CFU/100 毫升

Currently, UV radiation treatment is the safest and non-polluting inactivation technology, which has been widely used in the fields of water disinfection and food sterilisation [[4], [5], [6]]. Short-wave ultraviolet (UVC) has strong microbial transient inactivation ability, but the penetration ability is not strong, the inactivation effect is susceptible to the negative impact of suspended solids and dissolved iron in the water; long-wave ultraviolet (UVA) has strong penetration and photocatalytic ability, but the ability of inducing DNA damage is relatively weak. The joint action of multi-band UV can give full play to the advantages of different wavelengths of UV in biological inactivation and photocatalysis, and make up for the multiple defects of a single wavelength of UV under specific conditions, which is a more comprehensive and efficient disinfection treatment method [[7], [8], [9], [10]]. However, the traditional low-pressure and medium-pressure mercury lamps used in the multi-band disinfection process based on UV radiation have the defects of high energy consumption, easy to leak mercury to pollute the environment, and at the same time cannot efficiently inhibit the resurrection of pathogenic microorganisms and other defects. Improvement programme and measures have been taken to address the above problems. Firstly, replacing mercury vapour lamps as the UV radiation source with UV LED, which are highly efficient, long-lived and made of non-toxic materials, not only provides greater flexibility in the design of light sources for microbial reactors, but also has significantly lower energy consumption than that of traditional mercury lamps [11,12]. Secondly, nano-TiO₂, which has demonstrated excellent performance in the fields of environmental purification and antibacterial disinfection, was used as a photocatalytic material to improve the persistence of multi-band UV in the photodynamic inactivation of microorganisms [[13], [14], [15], [16], [17], [18], [19], [20]].
目前，紫外线辐射处理是最安全、无污染的灭活技术，已广泛应用于水消毒和食品杀菌领域 [[4]， [5]， [6]]。短波紫外线（UVC）具有较强的微生物瞬时灭活能力，但渗透能力不强，灭活作用易受水中悬浮物和溶解铁的负面影响;长波紫外线（UVA）具有很强的穿透力和光催化能力，但诱导 DNA 损伤的能力相对较弱。多波段紫外线的联合作用可以充分发挥不同波长紫外线在生物灭活和光催化方面的优势，弥补特定条件下单一波长紫外线的多重缺陷，是一种更全面、更高效的消毒处理方法 [[7]， [8]， [9]， [10]].然而，传统的基于紫外线辐射的多波段消毒过程中使用的低压和中压汞灯存在能耗高、易泄漏汞污染环境、同时不能有效抑制病原微生物复活等缺陷。已采取改善计划和措施来解决上述问题。首先，用高效、长寿命且由无毒材料制成的 UV LED 取代汞蒸气灯作为紫外线辐射源，不仅为微生物反应器的光源设计提供了更大的灵活性，而且比传统的汞灯能耗低得多[11,12]。其次，在环境净化和抗菌消毒领域表现出优异性能的纳米 TiO₂ 被用作光催化材料，以提高多波段紫外线在微生物光动力灭活中的持久性 [[13]， [14]， [15]， [16]， [17]， [18]、[19]、[20]]。

However, the relatively large forbidden bandwidth (~3.20 eV) of conventional TiO₂ allows it to be activated only in the near-ultraviolet range, which hampers large-scale commercial applications [14,21]. Therefore, several effective strategies have been employed by researchers to enhance the photocatalytic activity of TiO₂ as much as possible [[22], [23], [24], [25], [26], [27]]. Currently, the addition of metallic or non-metallic elements to TiO₂ to improve its overall efficiency is one of the most successful strategies [14]. The inhibition rates of Cu, Ni and Sn modified TiO₂ against Escherichia coli and Staphylococcus aureus were >99.9 % [[28], [29], [30]]. The addition of active antimicrobial noble metals (Ag, Pt, Au) inactivates intracellular enzymes and disrupts membrane permeability while reducing the energy required for electron leaps, which can reduce the survival rate of both Gram-positive and Gram-negative bacteria to almost 0 [[31], [32], [33]]. The efficiency of TiO₂ modified with non-metallic elements (N, C, S, etc.) that partially replace oxygen is higher than 80 % against opportunistic pathogens such as Pseudomonas aeruginosa [34,35]. Although several studies have demonstrated that the photocatalytic properties of TiO₂ modified with different elements are significantly enhanced per se, the effect of changes in the doping concentration of the same element has not been clarified in these literatures. With the help of X-ray diffraction, scanning electron and transmission electron microscopy, X-ray photoelectron spectroscopy, specific surface area analysis and UV–visible diffuse reflectance spectroscopy, some researchers have completed the characterisation of TiO₂ modified by different elements, revealing the influence of different elements on the structure and light absorption properties of TiO₂, and analysing the changes of photocatalytic activity by analysing the degradation rate of pollutants or the deactivation effect of microorganisms. Ultimately, it was found that not all elements doped TiO₂ showed positive effects, and the variation of elemental content affected the performance of modified TiO₂, and there existed an optimal doping concentration [36,37]. In addition, the small particle size of elementally modified TiO₂ is not easy to be filtered and precipitated, and its recycling and efficient recovery in the process of practical application are still a big problem [38]. In order to overcome these shortcomings, some researchers have loaded TiO₂ onto carriers of different shapes and materials or coated TiO₂ with magnetic substances as the core, which has greatly improved the reuse rate and service life of powder TiO₂ [39,40]. Therefore, we have further carried out research on the influence of the proportion of dopant elements on the degree of enhancement of the photocatalytic activity of TiO₂, as well as the enhancement of the recycling ability of TiO₂ modified with powdered elements. More importantly, the existing discussions have focused too much on the inactivation of different species of bacteria, while the specific study of TiO₂ photocatalytic treatment of algae, which have more complex cellular structures [41], remains undefined. In this study, the innovative photocatalytic disinfection of hard-to-remove bacteria and algae in ballast water using UVA/UVC_LED combined with magnetically modified TiO₂ composites is expected to prolong the service life of the LED light source, reduce energy consumption, clarify the inactivation mechanism of the microorganisms, and solve the difficulty in recycling the traditional powdered TiO₂. In terms of explaining the microbial inactivation process, the traditional first-level inactivation mechanistic model is based on the fact that all microorganisms have the same sensitivity to adversity, which can describe the inactivation phenomenon in most cases in a simple and convenient way [42,43]. However, Marugan et al. found that the classical first-order sterilisation Chick-Watson model does not reproduce the experimental results of photocatalytic inactivation of Escherichia coli [44]. Previous studies can give a reasonable explanation that some microorganisms can repair UV-damaged DNA through mechanisms such as photoactivation and dark repair. Photoactivation refers to the process by which microorganisms use light-activated photolytic enzymes to split dimers and directly repair damaged DNA with high specificity under the action of light at a wavelength of 330–480 nm. At the same time, dark repair is not dependent on light and can be used to excise and re-synthesise normal DNA strands through the involvement of a variety of enzymes, restoring the cell's ability to proliferate. Only when the repair mechanism fails to protect the cell, the microorganism becomes completely inactive. This leads to the fact that linear kinetic models do not describe the observed deviations in the inactivation process well, creating difficulties in assessing the physiological effects of microbial inactivation [[45], [46], [47]]. In order to more accurately determine the relationship between UV catalysis time and microbial survival and to understand the behaviour of microbial populations under different environmental conditions, it has become important to find a non-linear inactivation kinetic model with a high degree of fit.
然而，传统 TiO₂ 相对较大的禁止带宽（~3.20 eV）使其只能在近紫外范围内被激活，这阻碍了大规模的商业应用[14,21]。因此，研究人员采用了几种有效的策略来尽可能提高 TiO₂ 的光催化活性 [[22]， [23]， [24]， [25]， [26]， [27]]。目前，在 TiO₂ 中添加金属或非金属元素以提高其整体效率是最成功的策略之一 [14]。Cu、Ni 和 Sn 修饰的 TiO₂ 对大肠杆菌和金黄色葡萄球菌的抑制率为 >99.9 % [[28]， [29]， [30]]。添加活性抗菌贵金属（Ag、Pt、Au）使细胞内酶失活并破坏膜通透性，同时减少电子跃迁所需的能量，这会将革兰氏阳性菌和革兰氏阴性菌的存活率降低到几乎为零 [[31]， [32]， [33]]。用部分替代氧的非金属元素（N、C、S 等）改性的 TiO₂ 对铜绿假单胞菌等机会性病原体的效率高于 80 %[34,35]。尽管几项研究表明，用不同元素改性的 TiO₂ 的光催化性能本身得到了显著增强，但这些文献尚未阐明相同元素掺杂浓度变化的影响。在 X 射线衍射、扫描电子和透射电子显微镜、X 射线光电子能谱、比表面积分析和紫外-可见漫反射光谱的帮助下，一些研究人员完成了不同元素修饰的 TiO ₂ 的表征，揭示了不同元素对 TiO 2 结构和光吸收性能的影响，并通过分析污染物的降解速率或微生物的失活效应来分析光催化活性的变化。最终发现，并非所有掺杂 TiO 2 的元素都显示出积极影响，元素含量的变化影响了改性 TiO₂ 的性能，并且存在最佳掺杂浓度[36,37]。此外，元素改性 TiO₂ 的小粒径不易被过滤和沉淀，其在实际应用过程中的回收和高效回收仍然是一个大问题[38]。为了克服这些缺点，一些研究人员将 TiO₂ 负载到不同形状和材料的载体上，或者以磁性物质为核心涂覆 TiO₂，大大提高了粉末 TiO₂ 的再利用率和使用寿命[39,40 ]。因此，我们进一步开展了掺杂元素比例对 TiO 2 光催化活性增强程度的影响，以及粉末元素改性 TiO₂ 回收能力的增强。更重要的是，现有的讨论过于关注不同种类细菌的灭活，而 TiO₂ 光催化处理藻类的具体研究仍未确定，藻类具有更复杂的细胞结构 [41]。本研究利用 UVA/UVC_LED 结合磁改性 TiO₂ 复合材料对压载水中难以去除的细菌和藻类进行创新光催化消毒，有望延长 LED 光源的使用寿命，降低能耗，阐明微生物的灭活机制，解决传统粉末状 TiO₂ 的回收难。在解释微生物灭活过程方面，传统的一级灭活机理模型是基于所有微生物对逆境具有相同的敏感性这一事实，这在大多数情况下可以用简单方便的方式描述灭活现象 [42,43 ].然而，Marugan 等人发现，经典的一级灭菌 Chick-Watson 模型并不能重现光催化灭活大肠杆菌的实验结果 [44]。以前的研究可以给出一个合理的解释，即一些微生物可以通过光活化和暗修复等机制来修复被紫外线损伤的 DNA。光活化是指微生物在 330-480 nm 波长的光的作用下，利用光激活光解酶分裂二聚体并直接修复受损 DNA 的过程，具有高特异性。同时，暗修复不依赖于光，可用于通过多种酶的参与切除和重新合成正常的 DNA 链，恢复细胞的增殖能力。只有当修复机制无法保护细胞时，微生物才会完全失活。这导致线性动力学模型不能很好地描述在灭活过程中观察到的偏差，从而难以评估微生物灭活的生理效应 [[45]， [46]， [47]]。为了更准确地确定紫外线催化时间与微生物存活之间的关系，并了解不同环境条件下微生物种群的行为，找到一个高度拟合的非线性灭活动力学模型变得非常重要。

Based on this, this study proposed the UVA/UVC_LED + Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalytic technology to address the problems of high energy consumption and incomplete inhibition of microbial resurrection in the existing ballast water treatment technologies. Single and composite magnetic TiO₂ photocatalysts with different modification ratios were prepared, and the surface morphology of the photocatalysts was analysed using scanning electron microscopy (SEM). Using Karenia mikimotoi and Escherichia coli as target microorganisms, the bioinactivation effects of multi-band UV in conjunction with different types of photocatalysts were investigated, and the optimal elemental modification ratios of single-type and composite-type photocatalysts were derived. Some performance indexes of the photocatalysts (optimal dosage, cycling stability, magnetic separation performance) were experimentally investigated, and superoxide dismutase (SOD) activity was analysed. On this basis, the inactivation process of microorganisms under different treatments was analysed by completing the simulation of inactivation kinetics, fitting the kinetic model successfully to ballast water samples, and predicting the final microbial inactivation effect as a function of time.
基于此，本研究提出了 UVA/UVC_LED + Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化技术，以解决现有压载水处理技术中能耗高、微生物复活抑制不完全的问题。制备了不同修饰比例的单体和复合磁性 TiO₂ 光催化剂，并使用扫描电子显微镜（SEM）分析了光催化剂的表面形貌。以 Karenia mikimoşió 和 Escherichia coli 为靶标微生物，研究了多波段 UV 与不同类型光催化剂的生物灭活效果，并推导出了单一型和复合型光催化剂的最佳元素修饰比例。实验研究了光催化剂的一些性能指标（最佳剂量、循环稳定性、磁分离性能），并分析了超氧化物歧化酶（SOD）活性。在此基础上，通过完成灭活动力学模拟，将动力学模型成功拟合到压载水样品上，并预测最终微生物灭活效果随时间的变化，分析了微生物在不同处理下的灭活过程。

2. Materials and methods 2. 材料和方法

2.1. Artificial seawater preparation and microbiological culture
2.1. 人工海水制备和微生物培养

Artificial seawater prepared according to the Mocledon formula was used as the test water [48], and the temperature of the artificial seawater was maintained at 22 °C, salinity at 35 ‰, pH at 8.0, and turbidity at 10 NTU. Considering the universal applicability and the superiority of environmental adaptation of Karenia mikimotoi and Escherichia coli mentioned in the IMO D-2 performance standard, substantially increasing the level of harm to marine ecology and human health. Therefore, both were selected as target microorganisms for the study. The test microorganisms were obtained from the Algae Species Bank of the First Institute of Oceanography of the Ministry of Natural Resources and the Beijing Microbiological Culture Collection Centre, respectively. The algal stock was cultured in a biochemical incubator at a temperature of 22 °C, a light intensity of 5500 Lux, and a light-dark ratio of 12 h:12 h. The f/2 medium (22 °C) and LB liquid medium (37 °C) were used for the amplification culture of Karenia mikimotoi and Escherichia coli, respectively, and the logarithmic growth phase, which was more typical in morphology, staining and physiological activity and sensitive to the effects of external environmental factors, was selected for the inactivation test, at which time the concentrations of the two were 10⁵–10⁶ cells/mL and 10⁶–10⁷ CFU/mL, respectively.
以根据 Molbledon 公式制备的人工海水作为试验水[48]，人工海水的温度维持在 22 °C，盐度为 35 ‰，pH 为 8.0，浊度为 10 NTU。考虑到 IMO D-2 性能标准中提到的 Karenia mikimotoi 和 Escherichia coli 的普遍适用性和环境适应性优越性，大大增加了对海洋生态和人类健康的危害程度。因此，两者都被选为研究的目标微生物。测试微生物分别来自自然资源部第一海洋研究所藻类物种库和北京微生物培养保藏中心。将藻类原液在生化培养箱中培养，温度为 22 °C，光照强度为 5500 Lux，明暗比为 12 h：12 h。f/2 培养基（22 °C）和 LB 液体培养基（37 °C）分别用于 Karenia mikimotoi 和 Escherichia 大肠杆菌的扩增培养，选择形态学、染色和生理活性较典型且对外界环境因子影响敏感的对数生长期进行灭活试验，此时两者的浓度分别为 10^5-10 ⁶ 个细胞/mL 和 10 6-10⁷ CFU/mL。

2.2. Preparation of photocatalysts
2.2. 光催化剂的制备

A three-step synthesis method was used to prepare multifunctional modified magnetic TiO₂ composites. The specific steps were as follows: (a) FeCl₂·4H₂O, FeCl₃·6H₂O and NH₃·H₂O were used as raw materials, which were fully mixed according to the ratio of n(Fe²⁺):n(Fe³⁺):n(OH⁻) = 1:2:8 and stirred for 30 min before separating the Fe₃O₄ particles, which were washed and dried using deionised water. (b) Add 0.2 g Fe₃O₄, 9 mL concentrated ammonia, 16.25 mL anhydrous ethanol, and 24.75 mL deionised water, respectively, to flask A, and stir (1000 RPM) for 30 min. To flask B, 4.5 mL of tetraethyl orthosilicate (TEOS) and 45.5 mL of anhydrous ethanol were added separately and stirred (1000 RPM) for 10 min. The liquid in flask B was quickly poured into flask A. After stirring (500 RPM) for 24 h, the magnetic core-shell (Fe₃O₄-SiO₂) material was isolated, washed and dried thoroughly. The SiO₂ coating can prevent Fe₃O₄ from negatively affecting the photoactivity of TiO₂ while improving the antioxidant property of the material [49,50]. (c) 18 mL of tetrabutyl titanate (TBT) was slowly added dropwise into 84 mL of anhydrous ethanol with continuous stirring for 30 min to form a pale yellow mixed solution A. 0.5 g of Fe₃O₄-SiO₂, 42 mL of anhydrous ethanol, 6 mL of deionised water and 12 mL of glacial acetic acid were mixed with different molar fractions of AgNO₃ or CH₄N₂O (Table 2), and the appropriate amount of nitric acid was added to adjust the pH to 3, and mixture B was formed by stirring (500 RPM) for 30 min. Solution A was added drop by drop (1 drop/s) into B at 30 °C water bath with stirring, and stirring was continued for 1 h after the completion of dropwise addition to form mixture C. After solidification of C, it was dried at 80 °C, and calcined at 500 °C in a muffle furnace for 2 h, and then taken out and ground into powder. So far, single-type (Ag-Fe₃O₄-SiO₂-TiO₂, N-Fe₃O₄-SiO₂-TiO₂) and composite-type (Ag/N-Fe₃O₄-SiO₂-TiO₂) photocatalysts with different modification ratios were obtained.
采用三步合成法制备多功能改性磁性 TiO₂ 复合材料。具体步骤如下：（a） FeCl₂·4H₂O、FeCl₃·6H₂O 和 NH₃·以 H₂O 为原料，按 n（Fe²⁺）：n（Fe³⁺）：n（OH⁻） = 1：2：8 的比例充分混合，搅拌 30 min，分离出 Fe₃O₄ 颗粒，用去离子水洗涤和干燥。（b）向培养瓶 A 中分别加入 0.2 g Fe₃O₄、9 mL 浓氨、16.25 mL 无水乙醇和 24.75 mL 去离子水，搅拌（1000 RPM） 30 分钟。向培养瓶 B 中，分别加入 4.5 mL 正硅酸四乙酯（TEOS）和 45.5 mL 无水乙醇，并搅拌（1000 RPM） 10 分钟。将培养瓶 B 中的液体迅速倒入培养瓶 A 中。搅拌（500 RPM） 24 h 后，分离磁性核壳（Fe₃O 4-SiO₂）材料，彻底洗涤和干燥。SiO₂ 涂层可以防止 Fe₃O₄ 对 TiO 2 的光活性产生负面影响，同时提高材料的抗氧化性能[49\u201250]。（c）将 18 mL 钛酸四丁酯（TBT）缓慢滴加到 84 mL 无水乙醇中，持续搅拌 30 min，形成淡黄色混合溶液 A。将 0.5 g Fe₃O_4-SiO ₂、42 mL 无水乙醇、6 mL 去离子水和 12 mL 冰醋酸与不同摩尔分数的 AgNO₃ 或 CH₄N₂O 混合（表 2），以及适量的硝酸加入以将 pH 值调节至 3，通过搅拌（500 RPM） 30 分钟形成混合物 B。将溶液 A 逐滴（1 滴/秒）加入 B 中，在 30 °C 水浴中搅拌并搅拌，滴加完成后继续搅拌 1 小时，形成混合物 C。C 凝固后，在 80 °C 干燥，在马弗炉中于 500 °C 煅烧 2h ，然后取出研磨成粉末。到目前为止，获得了不同改性比例的单型（Ag-Fe₃O_4-SiO _2-TiO ₂、N-Fe₃O_4-SiO _2-TiO ₂）和复合型（Ag/N-Fe₃O_4-SiO _2-TiO ₂）光催化剂。

Table 2. Modification ratios of different elements.
表 2.不同元素的修改率。

Sample number 样本编号	Ag/(% Ti mole fraction) Ag/（% Ti 摩尔分数）	Ag/(g mass) Ag/（g 质量）	N/(% Ti mole fraction) N/（% Ti 摩尔分数）	N/(g mass) N/（g 质量）	Ag-N/(% Ti mole fraction) Ag-N/（% Ti 摩尔分数）	Ag-N/(g mass) Ag-N/（g 质量）
1	0	0	0	0	0–0	0–0
2	0.5	0.0449	1.0	0.0159	1.5–2.0	0.1348–0.0318
3	1.0	0.0898	2.0	0.0318	2.0–2.0	0.1797–0.0318
4	1.5	0.1348	3.0	0.0476	3.0–2.0	0.2695–0.0318
5	2.0	0.1797	4.0	0.0635	1.0–3.0	0.0898–0.0476
6	2.5	0.2246	5.0	0.0794	1.5–3.0	0.1348–0.0476
7	3.0	0.2695	6.0	0.0953	2.0–3.0	0.1797–0.0476

2.3. Characterisation of materials
2.3. 材料表征

The development of modern science provides powerful means for the analysis and characterisation of composite material interfaces. A variety of material analysis equipment has been fully applied in the analysis and characterisation of composite material interfaces, which has made important contributions to revealing the nature of interfaces and enriching the theory of interfaces [[51], [52], [53], [54], [55]]. The main instruments used in this study are X-ray diffractometer (BRUKER D8 ADVANCE), scanning electron microscope (ZEISS GeminiSEM 360), transmission electron microscope (FEI Talos F200S), ultraviolet-visible spectrophotometer (SHIMADZU, UV-3600i Plus), specific surface area pore size analyzer (MICROMERITICS 3Flex), laser Raman spectrometer (THERMO FISHER DXR 2xi), PL tester (EDINBURGH FLS1000).
现代科学的发展为复合材料界面的分析和表征提供了强大的手段。多种材料分析设备在复合材料界面的分析和表征中得到了充分应用，为揭示界面的性质和丰富界面理论做出了重要贡献[[51]， [52]， [53]， [54]， [55]]。本研究使用的主要仪器有 X 射线衍射仪（BRUKER D8 ADVANCE）、扫描电子显微镜（ZEISS GeminiSEM 360）、透射电子显微镜（FEI Talos F200S）、紫外可见分光光度计（SHIMADZU， UV-3600i Plus）、比表面积孔径分析仪（MICROMERITICS 3Flex）、激光拉曼光谱仪（THERMO FISHER DXR 2xi）、PL 测试仪（EDINBURGH FLS1000）。

2.4. Test device and operation process
2.4. 测试装置及作流程

The UVA/UVC_LED photocatalytic system was used to investigate the inactivation effect and mechanism of the combined action of multi-band UV and different types of photocatalysts. The 15 W UV LED lamps with different wavelengths (254 nm, 365 nm) were used as the radiation light source, and the specific flow diagram is shown in Fig. 1. The whole reaction device was made of transparent glass, equipped with UV LED light source, light shield and stirrer. The photocatalysts were evenly dispersed in the water samples to be treated using Karenia mikimotoi and Escherichia coli as the target algal species and strains, respectively, and keeping their initial concentrations of 10⁵–10⁶ cells/mL and 10⁶–10⁷ CFU/mL. During the test, the treated water samples were sampled and tested every 30 s to determine the biological concentration of the target microorganisms in the time period of 0–240 s. In order to reduce data errors, three parallel samples were analysed in each test and completed at room temperature.
采用 UVA/UVC_LED 光催化系统研究多波段 UV 与不同类型光催化剂联合作用的灭活效应和机理。以不同波长（254 nm、365 nm）的 15 W UV LED 灯作为辐射光源，具体流程图如图 1 所示。整个反应装置由透明玻璃制成，配备 UV LED 光源、遮光罩和搅拌器。光催化剂均匀分散在待处理的水样中，分别以 Karenia mikimoū 和 Escherichia coli 为目标藻类和菌株，并保持其初始浓度为 10⁵–10⁶ 个细胞/mL 和 10⁶–10⁷ CFU/mL。在测试过程中，每 30 秒对处理过的水样进行取样和测试，以确定目标微生物在 0-240 秒内的生物浓度。为了减少数据误差，在每次测试中分析三个平行样品，并在室温下完成。

2.5. Inactivation rate of microorganisms
2.5. 微生物灭活率

The number of viable organisms before and after inactivation of Karenia mikimotoi and Escherichia coli were determined by neutral red staining microscopy and plate counting methods, respectively. The operation methods were as follows: (a) Neutral red staining microscopy method [56]: take 2 mL of the sample to be tested in a centrifuge tube, add 30 μL of neutral red original stain at a concentration of 10 g/L into it, shake it well and leave it for 20 min, take 1 mL of the sample and observe it under a microscope, the dead cells would not be stained, and the living cells were stained with red colour. (b) Plate counting method [57]: Water quality-Determination of fecal coliform-Membrane filtration was used to determine the concentration of Escherichia coli. The inactivation effect of the UVA/UVC_LED photocatalytic system was reflected by determining the number of microbial cells before and after inactivation, which was calculated by the following formula:
分别采用中性红染色显微镜和平板计数法测定 Karenia mikimoto 和 Escherichia coli 灭活前后的活菌数。作方法如下：（a）中性红染色显微镜法[56]：取 2 mL 待测样品，放入离心管中，加入 30 μL 浓度为 10 g/L 的中性红原染剂，摇匀并放置 20 min，取样品 1 mL，在显微镜下观察，死细胞不会被染色，活细胞染成红色。（b）平板计数法 [57]：水质 - 粪便大肠菌群的测定 - 采用膜过滤测定大肠杆菌的浓度。UVA/UVC_LED 光催化系统的灭活效果是通过测定灭活前后的微生物细胞数量来体现的，其计算公式如下：(1)

η = - lg (\frac{N_{t}}{N_{0}})

Note: N_t represents the number of algal cells/number of colonies at different treatment times, and N₀ represents the total number of algal cells/total number of colonies before treatment.
注意：N_t 表示不同处理时间的藻类细胞数/菌落数，N₀ 表示处理前藻类细胞总数/菌落总数。

2.6. Determination of superoxide dismutase activity
2.6. 超氧化物歧化酶活性的测定

The activity of SOD (U/mL) was determined by pyrogallol autoxidation method [58]. (a) 4.5 mL Tris-HCL-EDTA buffer (pH = 8.0) and 10 μL of pyrogallol solution (45 mmol/L) were added to the cuvette, shaken rapidly, and the absorbance was measured at the wavelength of 325 nm at 30 s intervals for 4 min. The blank control group was 4.51 mL Tris-HCL-EDTA buffer (pH = 8.0) to determine the autoxidation rate A (ΔA/min) of pyrogallol. (b) 3.5 mL Tris-HCL-EDTA buffer (pH = 8.0), 1 mL sample and 10 μL pyrogallol solution (45 mmol/L) were added to the cuvette successively, and the above operation of pyrogallol autoxidation rate determination was repeated to determine the change rate B (ΔB/min) of the optical density value of the sample. (c) SOD activity was calculated according to formula 2.
SOD 活性（U/mL）通过邻苯三酚自氧化法测定 [58]。（a）向比色皿中加入 4.5 mL Tris-HCL-EDTA 缓冲液（pH = 8.0）和 10 μL 邻苯三酚溶液（45 mmol/L），快速摇动，在 325 nm 波长处以 30 s 的间隔测量吸光度 4 min。空白对照组用 4.51 mL Tris-HCL-EDTA 缓冲液（pH = 8.0）测定邻苯三酚的自氧化速率 A （ΔA/min）。（b）将 3.5 mL Tris-HCL-EDTA 缓冲液（pH = 8.0）、1 mL 样品和 10 μL 邻苯三酚溶液（45 mmol/L）依次加入比色皿中，重复上述邻苯三酚自氧化速率测定作，测定样品光密度值的变化率 B （ΔB/min）。（c）根据公式 2 计算 SOD 活性。(2)

SOD = \frac{\frac{A - B}{A} \times 100 %}{50 %} \times 4.51

Note: A represents the autoxidation rate of pyrogallol, and B represents the rate of change of the optical density value of the sample to be tested.
注意：A 表示邻苯三酚的自氧化速率，B 表示待测样品光密度值的变化速率。

2.7. Inactivation kinetics of microorganisms
2.7. 微生物的灭活动力学

Understanding the specific behaviour of microbial populations under different environmental conditions or treatments and predicting the effectiveness of UV disinfection over different time periods is an important task. Inactivation mechanistic models can capture the inactivation mechanism of microbial populations and determine the linear or non-linear relationship between changes in external conditions and microbial survival, which is suitable for mechanistic investigation of microbial inactivation. In this study, the experimental results were fitted to the corresponding inactivation mechanics equations by nonlinear regression techniques, the corresponding parameters of each model were obtained, and the fit coefficients (R²) and root-mean-square deviations (RMSD) were applied to assess the quality of the fit [43].
了解微生物种群在不同环境条件或处理下的具体行为，并预测不同时间段内紫外线消毒的有效性是一项重要的任务。灭活机理模型可以捕捉微生物种群的灭活机制，并确定外部条件变化与微生物存活之间的线性或非线性关系，适用于微生物灭活的机理研究。在本研究中，通过非线性回归技术将实验结果拟合到相应的失活力学方程中，获得每个模型的相应参数，并应用拟合系数（R²）和均方根偏差（RMSD）来评估拟合质量 [43]。

The Chick-Watson model (3) was initially used primarily to express the disinfection kinetics of chemical disinfectants, but based on the similarities between UV inactivation of microorganisms and chemical reactions, much of the modelling of UV inactivation kinetics has been done with this model in mind. The Chick-Watson model is a linear model, presenting in the representation of microbial inactivation as a function of the amount of UV irradiation as a straight line that adequately describes inactivation over an appropriate range. This is based on the fact that all microorganisms comprising a population have the same sensitivity to UV radiation. However, deviations from the Chick-Watson model in the experimental values derived from treating specific microorganisms can be observed in some cases, demonstrating the limitations of the linear kinetic model. Several studies have found that the inactivation behaviour of some bacteria is not linear but shows different curvilinear forms: concave (shoulder) and convex (tail) [59].
Chick-Watson 模型（3）最初主要用于表达化学消毒剂的消毒动力学，但基于微生物的紫外线灭活和化学反应之间的相似性，紫外线灭活动力学的大部分建模都是在考虑该模型的情况下完成的。Chick-Watson 模型是一个线性模型，将微生物灭活表示为紫外线照射量的函数，作为一条直线，充分描述了适当范围内的灭活。这是基于这样一个事实，即构成一个群体的所有微生物对紫外线辐射具有相同的敏感性。然而，在某些情况下，可以观察到处理特定微生物得出的实验值与 Chick-Watson 模型的偏差，这表明线性动力学模型的局限性。几项研究发现，一些细菌的灭活行为不是线性的，而是表现出不同的曲线形式：凹（肩）和凸（尾）[59]。(3)

lg (\frac{N_{t}}{N_{0}}) = - kt

Note: N_t and N₀ represent the number of surviving microorganisms in cells/mL or CFU/mL at time t and initial time, respectively; and k represents the kinetic rate constant.
注意：N_t 和 N₀ 分别表示在 t 和初始时间细胞中存活的微生物数量/mL 或 CFU/mL;k 表示动力学速率常数。

The Hom model (4), whose formulation dates back to 1972, can be applied to cases where the inactivation of specific microorganisms (Some bacteria) deviates from the classical linear model [60]. The only difference between this model and the Chick-Watson model is the introduction of the parameter h. When h = 1, the Hom model is identical to the Chick-Watson model; when h ≠ 1, the model can fit inactivation curves with shoulders (h > 1) or tails (h < 1).
Hom 模型（4）的公式可以追溯到 1972 年，可应用于特定微生物（某些细菌）失活偏离经典线性模型的情况 [60]。此模型与 Chick-Watson 模型之间的唯一区别是引入了参数 h。当 h = 1 时，Hom 模型与 Chick-Watson 模型相同;当 h ≠ 1 时，模型可以拟合肩部（h > 1）或尾部（h < 1）的失活曲线。(4)

lg (\frac{N_{t}}{N_{0}}) = - k t^{h}

Note: k represents the kinetic rate constant, and h represents the presence of a shoulder at the start of the reaction or a tail at the end of the reaction.
注意：k 表示动力学速率常数，h 表示反应开始时存在肩部或反应结束时存在尾部。

Cerf proposed an inactivation model based on two kinetic rate constants (Biphasic model) in 1977. The model assumes that populations of target microorganisms are heterogeneous and can be divided into two different types of subpopulations, which are heterogeneous in terms of their resistance to external conditions [43,61]. The sensitive population is non-resistant to adversity and the inactivation curve exhibits first-order linearity; the resistant population is resistant to adversity and the inactivation curve exhibits a slow-growing tailing phenomenon. The first stage of the Biphasic model has a fast response rate, corresponding to a large inactivation mechanical rate constant. The slow reaction rate consistent with the second stage, on the other hand, provides a good description of nonlinear experimental data with tailing phenomena. The model is expressed in logarithmic form as:
Cerf 于 1977 年提出了一种基于两个动力学速率常数（双相模型）的失活模型。该模型假设目标微生物种群是异质性的，可以分为两种不同类型的亚群，它们在对外部条件的抵抗力方面是异质性的[43,61]。敏感群体对逆境没有抵抗力，失活曲线呈一阶线性;抗性种群对逆境具有抵抗力，失活曲线表现出缓慢增长的拖尾现象。Biphasic 模型的第一阶段具有快速响应速率，对应于较大的失活机械速率常数。另一方面，与第二阶段一致的慢反应速率很好地描述了带有拖尾现象的非线性实验数据。该模型以对数形式表示为：(5)

lg (\frac{N_{t}}{N_{0}}) = - lg [p e^{- k_{1} t} + (1 - p) e^{- k_{2} t}]

Note: P represents the proportion of surviving microorganisms corresponding to the sensitive population, (1-P) is the proportion of surviving microorganisms corresponding to the resistant population, k₁ is the kinetic rate constant for the sensitive population, and k₂ is the kinetic rate constant for the resistant population.
注：P 代表对应于敏感群体的存活微生物的比例，（1-P）是对应于抗性群体的存活微生物的比例，k₁ 是敏感群体的动力学速率常数，k₂ 是抗性群体的动力学速率常数。

3. Results and discussion
3. 结果和讨论

3.1. Inactivation effects of photocatalysts with different modification ratios
3.1. 不同修饰比例的光催化剂的灭活效应

The inactivation performance of photocatalysts with different modification ratios on Karenia mikimotoi and Escherichia coli was explored under combined UVA/UVC_LED (Fig. 2). As shown in Fig. 2, a–b and e–f, the logarithmic inactivation rates of pure TiO₂ were 0.327 log and 0.525 log after irradiation by UVA/UVC_LED for 240 s. The inactivation of microorganisms by the reaction system appeared to be firstly increased and then decreased with the increase of Ag modification ratio. The inactivation efficiencies reached the maximum when the Ag modification ratio is 1.5 %, which are 0.827 log and 1.772 log, respectively. However, when the Ag modification ratio is 0.5 %, the logarithmic inactivation rate decreases to 0.523 log and 1.290 log, but still has a certain degree of improvement compared with the pure TiO₂ inactivation system. Therefore, the optimal modification ratio of Ag is 1.5 %, and too much or too little modification will lead to a decrease in the inactivation effect of the reaction system. The positive effect of Ag doping on the photocatalytic activity of pure TiO₂ has also been reported in many literatures. Overall, a moderate amount of Ag deposited in different forms of nanoparticles in the host TiO₂ matrix, its relatively high electron density not only provides additional electrons to the conduction band, but also acts as an electron acceptor to enhance the electron-hole separation, and ultimately transfers the generated or captured electrons to the adsorbed O₂, resulting in the production of more active substances on the catalyst surface [31,37]. Excessive Ag modification, on the contrary, enhances the recombination phenomenon of electrons and holes and increases the chance of electron-hole complexation [36]. In addition, excessive doping clogs the pores of TiO₂ and reduces the specific surface area of the modified TiO₂ nanoparticles, which significantly and negatively affects their particle size [62,63]. However, Perkas et al. were able to achieve a 4.0 log reduction in the number of viable cells in 60 min using Ag/TiO₂ composites prepared via sonochemistry, yet at a slower rate than the system we developed to treat Escherichia coli [64].
在 UVA/UVC_LED 联合下探索了不同修饰比例的光催化剂对 Karenia mikimotoi 和大肠杆菌的灭活性能（图 2）。如图 2 所示，a-b 和 e-f，在 UVA/UVC_LED 照射 240 s 后，纯 TiO₂ 的对数灭活率分别为 0.327 log 和 0.525 log。随着 Ag 修饰率的增加，反应体系对微生物的失活表现为先增加后降低。当 Ag 修饰率为 1.5 % 时，灭活效率达到最大值，分别为 0.827 log 和 1.772 log。然而，当 Ag 修饰率为 0.5 % 时，对数灭活率降低到 0.523 log 和 1.290 log，但与纯 TiO₂ 灭活体系相比仍有一定程度的提高。因此，Ag 的最佳修饰比例为 1.5 %，过多或过少的修饰都会导致反应体系的灭活效果降低。Ag 掺杂对纯 TiO₂ 光催化活性的积极影响也在许多文献中报道。总体而言，适量的 Ag 沉积在宿主 TiO 2 基体中不同形式的纳米颗粒中，其相对较高的电子密度不仅为导带提供了额外的电子，而且还充当电子受体以增强电子-空穴分离，并最终将产生或捕获的电子转移到吸附的 O₂，导致催化剂表面产生更多的活性物质[31,37]。相反，过度的 Ag 修饰增强了电子和空穴的复合现象，增加了电子-空穴络合的机会[36]。此外，过度掺杂会堵塞 TiO₂ 的孔隙，降低改性 TiO₂ 纳米颗粒的比表面积，从而显著地消极地影响其粒径[62,63]。然而，Perkas 等人能够使用通过声化学制备的 Ag/TiO₂ 复合材料在 60 分钟内将活细胞数量减少 4.0 对数，但速度比我们开发的处理大肠杆菌的系统要慢 [64]。

Similarly, the inactivation efficiency of the reaction system against the target microorganisms varied similarly to Ag modification as the percentage of N modification increased (In Fig. 2, c and g). The inactivation efficiencies reached a maximum when the N modification ratio was 3 %, which were 0.671 log and 1.252 log, respectively, an increase of 0.344 log and 0.728 log compared to pure TiO₂. Continuing to increase the proportion of N modification inactivation efficiency began to decrease, when the proportion of N modification of 6 %, the logarithmic inactivation rate of the system decreased to 0.445 log and 0.922 log, but still has a better inactivation effect than the pure TiO₂. The reason is that the appropriate amount of N modification can reduce the forbidden band width of pure TiO₂, lower the energy of electron jump, and improve the photocatalytic activity of the catalyst [14]. However, excessive N doping exerted an inhibitory effect on the photocatalyst activity. It is because more N doping into the TiO₂ lattice leads to the creation of excessive oxygen vacancies, which in turn promotes electron-hole complexation [65]. Therefore, the optimal proportion of N modification can be determined as 3 %. However, the N modified TiO₂ developed by Ananpatharachai et al. required a long 5 h to achieve 1.0 log inactivation of Escherichia coli [66].
同样，随着 N 修饰百分比的增加，反应系统对目标微生物的灭活效率与 Ag 修饰相似（在图 2 中，c 和 g）。当 N 修饰率为 3 % 时，灭活效率达到最大值，分别为 0.671 log 和 1.252 log，与纯 TiO₂ 相比增加了 0.344 log 和 0.728 log。继续增加 N 修饰的灭活效率比例开始降低，当 N 修饰的比例为 6 % 时，体系的对数灭活率下降到 0.445 log 和 0.922 log，但仍具有优于纯 TiO₂ 的灭活效果。原因是适量的 N 改性可以减少纯 TiO 2 的禁止带宽，降低电子跳跃的能量，提高催化剂的光催化活性 [14]。然而，过量的 N 掺杂对光催化剂活性产生了抑制作用。这是因为更多的 N 掺杂到 TiO₂ 晶格中会导致产生过多的氧空位，进而促进电子-空穴络合 [65]。因此，氮改性的最佳比例可以确定为 3 %。然而，Ananpatharachai 等人开发的 N 修饰的 TiO 2 需要 5 小时才能实现 1.0 对数的大肠杆菌失活 [66]。

Different modification ratios of Ag/N-Fe₃O₄-SiO₂-TiO₂ had important effects on the performance of photocatalytic inactivation of target microorganisms and were more effective than those of the reaction system s with single modification of Ag or N (In Fig. 2, d and h). The best bioinactivation effect was achieved at 1.5 % Ag and 3 % N modification, with 1.421 log and 2.636 log, respectively, and the worst bioinactivation effect was achieved at 2 % Ag and 2 % N modification, with 0.974 log and 1.968 log, respectively, which was still higher than that of the reaction systems with single Ag or N modification. The modification of Ag changes the electron migration mode and forms a Schottky Barrier at the interface of Ag and TiO₂, which puts the electrons and holes in different two phases [67]. Meanwhile, the modification of N induces hybridisation of O_2P orbitals and N_2P orbitals, altering the electronic energy band structure of TiO₂, thus effectively narrowing the TiO₂ forbidden band width [68]. The combined effect of the two elements on TiO₂ enhances its photocatalytic activity and achieves a more efficient bioinactivation capability of the system. The efficient photocatalyst developed in this study can significantly reduce the processing time of the system when reaching the same inactivation rate. Efficiency analyses based on flux and energy have been documented to confirm that UV_LED photocatalytic systems are a good choice for reducing electrical energy consumption [69,70]. The antimicrobial property of Ag itself further enhances the inactivation efficiency of the reaction system [14]. Therefore, it was determined that the photocatalyst with a modification ratio of 1.5 % Ag/3 % N had the best performance and the best inactivation effect on harmful microorganisms in ballast water. The effectiveness of TiO₂ coatings co-doped with Ag and N to inhibit Staphylococcus aureus was explored by Dziedzic et al. After 1 h of UV radiation, the percentage reduction of cell population reached 55.1 % [71]. Although Staphylococcus aureus is slightly more resistant to UV than Escherichia coli, the significant inhibition of Karenia mikimotoi and Escherichia coli by the present system proves that it possesses a more superior ability to treat microorganisms.
Ag/N-Fe₃O_4-SiO _2-TiO ₂ 的不同修饰比例对目标微生物的光催化灭活性能有重要影响，并且比 Ag 或 N 单一修饰的反应体系更有效（图 2，d 和 h）。生物灭活效果最好，在 1.5 % Ag 和 3 % N 修饰时，分别为 1.421 log 和 2.636 log，在 2 % Ag 和 2 % N 修饰时生物灭活效果最差，分别为 0.974 log 和 1.968 log，仍高于单一 Ag 或 N 修饰的反应体系。Ag 的修饰改变了电子迁移模式，并在 Ag 和 TiO 2 的界面处形成了肖特基势垒，这使电子和空穴处于不同的两相中 [67]。同时，N 的修饰诱导 O_2P 轨道和 N_2P 轨道的杂化，改变了 TiO 2 的电子能带结构，从而有效地缩小了 TiO₂ 禁止带宽 [68]。两种元素对 TiO₂ 的联合作用增强了其光催化活性，实现了体系更有效的生物灭活能力。本研究开发的高效光催化剂在达到相同的灭活速率时，可以显著减少体系的处理时间。基于磁通量和能量的效率分析已经证明，UV_LED 光催化系统是减少电能消耗的不错选择[69,70]。Ag 本身的抗菌特性进一步提高了反应系统的灭活效率 [14]。因此，确定改性比为 1.5 % Ag/3 % N 的光催化剂对压载水中有害微生物的性能最佳，灭活效果最好。Dziedzic 等人探讨了 TiO₂ 涂层与 Ag 和 N 共掺杂抑制金黄色葡萄球菌的有效性。紫外线照射 1 小时后，细胞群减少的百分比达到 55.1 % [71]。虽然金黄色葡萄球菌对紫外线的抵抗力略高于大肠杆菌 ，但目前的系统对 Karenia mikimoto 和大肠杆菌的显着抑制证明它具有更优越的微生物治疗能力。

After analysis, it was determined that the difference in cost of the composites with different doping ratios was due to the addition of different masses of silver nitrate and urea. The increased cost of silver nitrate and urea dosage for the optimal doping concentration was calculated to be only CNY 22.77 per gram, while the logarithmic inactivation rate of the system was significantly increased by a factor of 4–5. The small increase in cost in exchange for a significant increase in the overall efficiency of the system offers considerable possibilities for practical application in engineering.
经过分析，确定不同掺杂比复合材料的成本差异是由于添加了不同质量的硝酸银和尿素所致。计算出最佳掺杂浓度的硝酸银和尿素剂量增加的成本仅为每克 22.77 元人民币，而系统的对数灭活率显着增加了 4-5 倍。成本的小幅增加换取了系统整体效率的显着提高，为工程中的实际应用提供了相当大的可能性。

3.2. Performance analysis and SEM of photocatalysts
3.2. 光催化剂的性能分析和 SEM

Fig. 3a shows the inactivation effects of different dosages of Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalysts on Karenia mikimotoi under the same UV inactivation conditions. The results showed that with the increase of catalyst dosage (300–700 mg/L), the inactivation effect of the system showed a tendency of increasing and then decreasing, and there was an optimal inactivation effect at a dosage of 500 mg/L. This is due to the fact that when the catalyst dosage is <500 mg/L, increasing the catalyst dosage will cause the increase of surface active sites, which will produce more active substances to accelerate the biological death; however, the excessive catalyst powder (>500 mg/L) dispersed in the treated water samples blocked the ultraviolet light and suppressed most of the photon energy absorbed by the catalyst, which led to the decrease of the overall inactivation effect of the reaction system. In addition, similar observations can be found in other studies. Kanakaraju et al. studied the application of Mo-TiO₂ in the degradation of methyl orange, and proved that 10 g/L was the optimal dosage value of the photocatalyst [72]. Nguyen et al. used Pt-TiO₂ to compare the degradation of methylene blue or methyl orange, and found that methylene blue or methyl orange showed the highest degradation efficiency at a dosage of 1.5 g/L [73]. The optimal dosage of Ag/N-Fe₃O₄-SiO₂-TiO₂ in this study is significantly lower, which can reduce the risk of environmental pollution and economic cost in large-scale application. It is an excellent photocatalytic material with higher cost performance.
图 3a 显示了在相同紫外线灭活条件下，不同剂量的 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化剂对 Karenia mikimotoi 的灭活效果。结果表明，随着催化剂用量的增加（300–700 mg/L），体系的灭活效果呈先增后减的趋势，在 500 mg/L 的用量时灭活效果最佳。这是因为当催化剂用量为 <500 mg/L 时，增加催化剂用量会导致表面活性位点的增加，从而产生更多的活性物质来加速生物死亡;然而，分散在处理水样中的过量催化剂粉末（>500 mg/L）阻挡了紫外线，抑制了催化剂吸收的大部分光子能量，导致反应体系的整体灭活效果降低。此外，在其他研究中也可以找到类似的观察结果。Kanakaraju 等人研究了 _{Mo-TiO 2} 在甲基橙降解中的应用，并证明 10 g/L 是光催化剂的最佳剂量值[72]。Nguyen 等人使用 Pt-TiO₂ 比较了亚甲基蓝或甲基橙的降解情况，发现亚甲基蓝或甲基橙在 1.5 g/L 的剂量下表现出最高的降解效率[73]。本研究中 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 的最佳掺量显著降低，可降低大规模应用的环境污染风险和经济成本。它是一种优异的光催化材料，具有更高的性价比。

In order to verify the magnetic separation and stability ability of the optimal photocatalyst under UVA/UVC_LED irradiation, six recycling tests were carried out, as shown in Fig. 3b and c. The results showed that the logarithmic inactivation rate of the treatment system was 1.360 log at the initial use, and the initial recovery efficiency of the photocatalyst was as high as 98.99 %. With the increase of the number of cycles, there was a small decrease in the stability and magnetic separation performance of the catalyst. The inactivation rate after 6 cycles was only 8.76 % lower than that of the initial use, and the recovery efficiency was still up to 95.75 %. It indicates that Ag/N-Fe₃O₄-SiO₂-TiO₂ has stable photocatalytic performance and can be easily recycled and reused several times by the external magnet, which solves the disadvantage of traditional powder TiO₂ that is not easy to be separated and recycled. This is closely related to the stable presence of Ag and N in the TiO₂ lattice and the firm coating on the surface of SiO₂ core-shell material, as well as the tight wrapping of nano Fe₃O₄ in the SiO₂ core-shell material to prevent the loss of magnetism by the damage of free radicals. The Ch_b/NH₂-Fe₃O₄-SiO₂-TiO₂ photocatalyst prepared by Heidari et al. showed acceptable reusability (>79 %) in three consecutive runs, but the photocatalytic efficiency deteriorated significantly to 65 % after the 4th cycle of recycling and reuse [74]. Bonnefond et al. completed a recyclability test for magnetic titanium dioxide/polystyrene/magnetite composite hybrid polymer particles, where complete degradation of methylene blue was achieved in the first three cycles, with a slight decrease in degradation efficiency in cycles 4 and 5 (still above 90 % of conversion) [75]. However, the photocatalytic activity of the optimal photocatalyst in this study was still 91.24 % after six cycles, which proves that its stability and reusability are better than some similar photocatalysts that have been developed.
为了验证最佳光催化剂在 UVA/UVC_LED 照射下的磁分离和稳定性能力，进行了 6 次回收试验，如图 3b 和 c 所示。结果表明，该处理系统在初次使用时的对数灭活率为 1.360 log，光催化剂的初始回收效率高达 98.99 %。随着循环次数的增加，催化剂的稳定性和磁分离性能略有下降。6 次循环后的灭活率仅比初次使用低 8.76 %，回收效率仍高达 95.75 %。这表明 Ag/N-Fe₃O 4-SiO 2-TiO ₂ 具有稳定的光催化性能，易于通过外部磁体回收再利用多次，解决了传统粉末 TiO₂ 不易分离和回收的缺点。这与 TiO₂ 晶格中 Ag 和 N 的稳定存在和 SiO₂ 核壳材料表面的牢固涂层以及纳米 Fe₃O₄ 在 SiO₂ 核壳材料中的紧密包裹以防止自由基损伤失去磁性密切相关。 Heidari 等人制备的 Ch _b/NH_{2-Fe 3} O_4-SiO _2-TiO ₂ 光催化剂在连续三次运行中显示出可接受的可重用性（>79 %），但在第 4 次回收和再利用循环后，光催化效率显著恶化至 65 %[74]。Bonnefond 等人。完成了磁性二氧化钛/聚苯乙烯/磁铁矿复合杂化聚合物颗粒的可回收性测试，其中前三个循环实现了亚甲蓝的完全降解，在循环 4 和 5 中降解效率略有下降（仍高于转化率的 90 %）[75].然而，本研究中最佳光催化剂的光催化活性在 6 次循环后仍为 91.24 %，这证明其稳定性和可重用性优于一些已开发的类似光催化剂。

In order to determine the micro-morphology of different types of photocatalysts, scanning electron microscopy tests (10,000 times magnification) were carried out on pure TiO₂, 1.5 % Ag-mono-modified TiO₂, 3 % N-mono-modified TiO₂, and 1.5 % Ag/3 % N-double-modified TiO₂, respectively. Fig. 4a–d shows the surface micromorphology of the four samples, and the particle sizes of the photocatalysts were all in the nanometer scale. The pure TiO₂ without elemental modification has a larger particle size (average ~250 nm) and obvious agglomeration. Compared with the pure TiO₂, the Ag and N modified TiO₂ particles were more regular spherical, with reduced particle size and improved agglomeration. After doping Ag and N, they can be attached to the TiO₂ surface to improve the specific surface area of the material and increase the effective contact area with UV light. The formation of the porous structure will facilitate the transfer of electron transport in the internal and external surface channels of the material, which is expected to generate more active radicals, not only improving the photocatalytic performance, but also enabling the treatment system to maintain a relatively low power consumption while taking into account the inactivation efficiency. Fig. 4e shows the SEM image of Ag/N-Fe₃O₄-SiO₂-TiO₂ after 6 cycles of recycling (10,000 times magnification). Theoretically, the photocatalyst can maintain the original state before and after the reaction and continue to play a catalytic role. After repeated use, it was found that the photocatalysts only underwent minor changes such as fragmentation, coking or carbon accumulation under the interference of external effects, which ensured that the photocatalytic removal efficiency remained high (>91.24 %) even after repeated use.
为了确定不同类型光催化剂的微观形貌，分别对纯 TiO₂、1.5 % Ag-单改性 TiO₂、3 % N-单改性 TiO₂ 和 1.5 % Ag/3 % N-双改性 TiO₂ 进行了扫描电子显微镜测试（放大 10,000 倍）。图 4a-d 显示了四个样品的表面微形貌，光催化剂的粒径都在纳米尺度上。未经元素修饰的纯 TiO₂ 具有更大的粒径（平均 ~250 nm）和明显的团聚。与纯 TiO₂ 相比，Ag 和 N 改性的 TiO₂ 颗粒更规则，粒径更小，团聚性更好。掺杂 Ag 和 N 后，它们可以附着在 TiO₂ 表面，以提高材料的比表面积并增加与紫外光的有效接触面积。多孔结构的形成将促进电子传输在材料的内外表面通道中转移，有望产生更多的活性自由基，不仅提高了光催化性能，而且使处理系统在兼顾灭活效率的同时，能够保持相对较低的功耗。图 4e 显示了 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 经过 6 次循环（放大 10,000 倍）后的 SEM 图像。理论上，光催化剂可以保持反应前后的原始状态，并继续发挥催化作用。反复使用后发现，光催化剂在外界作用的干扰下仅发生碎裂、焦化或积碳等微小变化，保证了光催化去除效率即使在重复使用后仍保持较高水平（>91.24 %）。

3.3. XRD analysis 3.3. XRD 分析

The crystal structures of Fe₃O₄, Fe₃O₄-SiO₂ and Ag/N-Fe₃O₄-SiO₂-TiO₂ and their patterns of change were analysed using X-ray diffractometer (Fig. 5). It can be seen that the diffraction peaks located at 2

θ

= 18.41°, 30.18°, 35.54°, 43.20°, 53.56°, 57.09°, 62.65°, and 74.11° corresponded to the (111), (220), (311), (400), (422), (511), (440), and (533) crystal faces of Fe₃O₄, respectively. The absence of other impurity peaks indicates that the prepared samples belong to high purity Fe₃O₄ crystals. In addition, due to the small amount of SiO₂ added to encapsulate Fe₃O₄, and as a cladding layer has been completely dispersed and deposited onto the surface of Fe₃O₄. Therefore, no obvious characteristic peaks of SiO₂ were found in the XRD pattern of Fe₃O₄-SiO₂, but the presence of SiO₂ was proved in combination with the image of TEM. In the XRD pattern of Ag/N-Fe₃O₄-SiO₂-TiO₂ composites, the main diffraction peaks are 2

θ

= 25.40°, 37.90°, 48.05°, 53.98°, 55.01°, 62.94°, 68.93°, 70.05° and 75.20°, which correspond to the (101), (004), (200), (105), (211), (204), (116), (220) and (215) crystal planes of anatase TiO₂, respectively. In the three-layer composites with core-shell structure, Fe₃O₄ also has a tiny addition, and a weak Fe₃O₄ characteristic peak appears at 2

θ

= 35.60° (·), and the other characteristic peaks are masked or attenuated by the characteristic peaks of TiO₂. More importantly, the crystalline structure of TiO₂ did not change with Ag and N doping. However, the characteristic peaks of substances containing Ag and N elements were not observed in the plots, which might be caused by the very small concentration of Ag and N doping below the detection limit of the instrument. Therefore, the successful doping of Ag and N into TiO₂ was subsequently confirmed by BET, PL, UV–Vis, and Raman analyses.
使用 X 射线衍射仪分析了 Fe₃O₄、Fe₃O_4-SiO ₂ 和 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 的晶体结构及其变化模式（图 5）。可以看出，位于 2

θ

= 18.41°、30.18°、35.54°、43.20°、53.56°、57.09°、62.65° 和 74.11° 处的衍射峰分别对应于 Fe₃O₄ 的（111）、（220）、（311）、（400）、（422）、（511）、（440）和（533）晶面。没有其他杂质峰表明制备的样品属于高纯度的 Fe₃O₄ 晶体。此外，由于添加少量的 SiO₂ 以封装 Fe₃O₄，并且作为包层已完全分散并沉积在 Fe₃O₄ 的表面上。因此，在 Fe₃O 4-SiO₂ 的 XRD 图谱中没有发现明显的 SiO₂ 特征峰，但结合 TEM 图像证明了 SiO₂ 的存在。在 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 复合材料的 XRD 图谱中，主要衍射峰分别为 2

θ

= 25.40°、37.90°、48.05°、53.98°、55.01°、62.94°、68.93°、70.05°和 75.20°，分别对应于锐钛矿 TiO 2 的（101）、（004）、（200）、（105）、（211）、（204）、（116）、（220）和（215）晶面。在具有核壳结构的三层复合材料中，Fe₃O₄ 也有微小的添加量，在 2

θ

= 35.60° （·）处出现一个弱的 Fe₃O₄ 特征峰，其他特征峰被 TiO₂ 的特征峰掩盖或衰减。更重要的是，TiO₂ 的晶体结构不随 Ag 和 N 掺杂而改变。然而，在图中没有观察到含有 Ag 和 N 元素的物质的特征峰，这可能是由于低于仪器检测限的 Ag 和 N 掺杂浓度非常小造成的。因此，随后通过 BET、PL、UV-Vis 和拉曼分析证实了 Ag 和 N 成功掺杂到 TiO₂ 中。

3.4. TEM analysis 3.4. TEM 分析

In order to more intuitively analyse the microscopic morphology and structure of the composites with core-shell structure, the Fe₃O₄, Fe₃O₄-SiO₂ and Ag/N-Fe₃O₄-SiO₂-TiO₂ were observed by transmission electron microscopy, respectively. As shown in Fig. 6b, the polyhedral shaped Fe₃O₄ particles were treated with a layer of SiO₂ uniformly attached to the outer surface, and the composites were nearly spherical and relatively smooth. Fig. 6c clearly shows that a shell layer consisting of Ag/N-TiO₂ nanoparticles grows on the outer layer of the Fe₃O₄-SiO₂ material, which has a relatively rough surface and a good mesoporous structure. In addition, we have completed high-resolution transmission studies of the above three materials (Fig. 6d–e), and it can be determined that all three are highly crystalline. The lattice spacing of 0.26 nm corresponds to the (311) crystal plane of Fe₃O₄ and the lattice spacing of 0.35 nm corresponds to the (101) crystal plane of TiO₂, which is in agreement with the XRD analysis. Comprehensive TEM analyses can strongly demonstrate the effectiveness of the three-step synthesis method and the dispersion and homogeneity of the composites in terms of microstructure, and indicate the successful preparation of Ag/N-Fe₃O₄-SiO₂-TiO₂ with core-shell structure.
为了更直观地分析具有核壳结构的复合材料的微观形貌和结构，通过透射电子显微镜分别观察了 Fe 3 O 4、Fe 3 O_4-SiO 2 和 Ag/N-Fe 3 O_4-SiO _2-TiO 2 。如图 6b 所示，多面体形状的 Fe₃O₄ 颗粒在外表面均匀地附着了一层 SiO₂ 处理，复合材料接近球形且相对光滑。图 6c 清楚地表明，由 Ag/N-TiO₂ 纳米颗粒组成的壳层生长在 Fe₃O 4-SiO₂ 材料的外层，该材料具有相对粗糙的表面和良好的介孔结构。此外，我们已经完成了上述三种材料的高分辨率透射研究（图 6d-e），可以确定这三种材料都是高度结晶的。0.26 nm 的晶格间距对应于 Fe₃O₄ 的（311）晶面，0.35 nm 的晶格间距对应于 TiO₂ 的（101）晶面，这与 XRD 分析一致。全面的透射电镜分析可以有力地证明三步合成方法的有效性以及复合材料在微观结构方面的分散性和均匀性，并表明成功制备了具有核壳结构的 Ag/N-Fe ₃O_4-SiO _2-TiO ₂。

3.5. UV–vis DRS analysis 3.5. 紫外-可见光 DRS 分析

In order to investigate the optical properties of the prepared photocatalysts and to determine their specific forbidden bandwidths, the absorption edges of TiO₂ modified with different elements were analysed using UV–vis DRS. Fig. 7 shows the UV diffuse reflectance profiles and forbidden bandwidth profiles of TiO₂ modified by different elements. The TiO₂ modified by Ag or N mono-modification showed a significant red-shift of the absorption edge relative to the unmodified TiO₂, and significantly increased the absorption in the visible region, which was about 439 nm and 448 nm. In addition, the light absorption ability of TiO₂ co-modified with Ag and N (absorption edge of about 459 nm) is again significantly increased in the whole spectral range, which substantially increases its utilization of sunlight. According to the Kubelka-Munk formula,

{(ahv)}^{2} = B (hv - E_{g})

α

is the absorption coefficient,

h

is Planck's constant,

v

is the incident light frequency,

B

is a material-related physical quantity,

E_{g}

is the forbidden bandwidth, and

n

is the type of semiconductor jump. The calculated forbidden bandwidth value of unmodified TiO₂ is about 3.23 eV, which is consistent with the reported value of about 3.20 eV for standard anatase TiO₂ [14]. As shown in Fig. 7b, we also found that the doping of different elements reduced the forbidden bandwidth of the conventional TiO₂, which can confirm that the photocatalytic performance of TiO₂ after elemental modification has been improved to some extent.
为了研究所制备的光催化剂的光学性质并确定其特定的禁止带宽，使用紫外-可见 DRS 分析了用不同元素改性的 TiO ₂ 的吸收边缘。图 7 显示了不同元素改性的 TiO₂ 的紫外漫反射曲线和禁止带宽曲线。经 Ag 或 N 单改性的 TiO₂ 显示出相对于未改性的 TiO₂ 的吸收边缘的显著红移，并显着增加了可见光区域的吸收，约为 439 nm 和 448 nm。此外，TiO ₂ 与 Ag 和 N 共改性的光吸收能力（吸收边缘约为 459 nm）在整个光谱范围内再次显着增加，这大大提高了其对太阳光的利用。根据 Kubelka-Munk 公式，

{(ahv)}^{2} = B (hv - E_{g})

α

是吸收系数，

h

是普朗克常数，

v

是入射光频率，

B

是与材料相关的物理量，

E_{g}

是禁止带宽，

n

是半导体跳跃的类型。未经修饰的 TiO₂ 的计算禁止带宽值约为 3.23 eV，这与标准锐钛矿 TiO₂ 的报道值约为 3.20 eV 一致[14]。如图 1 所示。 7b，我们还发现不同元素的掺杂降低了常规 TiO₂ 的禁带，这可以证实元素修饰后 TiO₂ 的光催化性能得到了一定程度的改善。

3.6. PL analysis 3.6. PL 分析

After light irradiation, different types of photocatalysts produce a certain degree of photoresponse, which leads to the spatial separation of photogenerated carriers, but at the same time, some photogenerated carriers also produce the recombination phenomenon. The recombination of photogenerated carriers generates PL emission spectra, which can reveal the effect of spatial separation of photogenerated carriers to a certain extent, and it is shown that the increase of the signal intensity of the PL spectra is positively correlated with the electron-hole composite. Fig. 8 shows the PL spectra of Fe₃O₄-SiO₂-TiO₂, Ag-Fe₃O₄-SiO₂-TiO₂, N-Fe₃O₄-SiO₂-TiO₂ and Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalysts samples, which have basically similar PL spectral patterns, with no obvious differences in peak shapes and positions, and all have a wide range of peak positions in the wavelength interval 400–600 nm. Among the four composite photocatalytic materials, Ag/N-Fe₃O₄-SiO₂-TiO₂ material has the weakest intensity of PL emission spectrum, which directly indicates that the number of photogenerated carrier complexes in TiO₂ modified by Ag and N is the lowest, and the chances of photogenerated carrier complexes have been effectively suppressed. The reason for this is that, in terms of the morphological structure of the Ag/N-Fe₃O₄-SiO₂-TiO₂ material, the excellent mesoporous structure can promote the rapid transfer of the photogenerated carriers to the surface of the photocatalysts and reduce the chance of electron-hole complexation. In addition, the photocatalyst with a larger specific surface area can adsorb more water to combine with holes to form active substances with strong oxidative properties, which also promotes the separation of photogenerated carriers. Combined with UV–vis, BET, TEM and other material characterisation means, the Ag/N-Fe₃O₄-SiO₂-TiO₂ composites have stronger absorption of incident light and lower carrier complexation chances, which endowed them with superior photocatalytic performance.
光照射后，不同类型的光催化剂产生一定程度的光响应，导致光生载流子的空间分离，但同时，一些光生载流子也产生复合现象。光生载流子的复合生成了光生载流子的发射光谱，可以在一定程度上揭示了光生载流子的空间分离效应，结果表明，光原光谱信号强度的增加与电子-空穴复合呈正相关。图 8 显示了 Fe₃O 4-SiO_2-TiO ₂、Ag-Fe₃O_4-SiO _2-TiO ₂、N-Fe₃O_4-SiO _2-TiO ₂ 和 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化剂样品的光致发光光谱，它们具有基本相似的光致发光光谱模式，峰形和位置没有明显差异，并且在 400–600 nm 的波长范围内具有很宽的峰位置范围。在四种复合光催化材料中，Ag/N-Fe₃O_4-SiO _2-TiO ₂ 材料的 PL 发射光谱强度最弱，这直接表明 Ag 和 N 改性的 TiO₂ 中光生载流子络合物的数量最低，光生载流子络合物的机会得到了有效抑制。其原因是，就 Ag/N-Fe₃O 4-SiO_2-TiO ₂ 材料的形貌结构而言，优异的介孔结构可以促进光生载流子快速转移到光催化剂表面，减少电子-空穴络合的机会。此外，比表面积较大的光催化剂可以吸附更多的水与空穴结合，形成具有强氧化性能的活性物质，这也促进了光生载流子的分离。结合紫外-可见光、BET、TEM 等材料表征手段，Ag/N-Fe₃O_4-SiO 2-TiO₂ 复合材料对入射光具有更强的吸收能力和较低的载流子络合机会，使其具有优异的光催化性能。

3.7. Raman analysis 3.7. 拉曼分析

Raman spectra based on the interaction between light and the chemical bonds within the material can provide important information about the chemical structure, crystallinity, etc. of the sample. Fig. 9 shows the Raman spectra of different types of photocatalyst samples. It has been reported that the Raman shift wavenumbers of anatase TiO₂ are 399, 515 and 639 cm⁻¹, respectively, and the corresponding vibration modes are B_1g, A_1g and B_2g. The Raman shift wavenumbers of Fe₃O₄-SiO₂-TiO₂ composites in the figure are 395.00, 508.78 and 628.35 cm⁻¹, respectively, which can be well corresponded to it. The doping of Ag and N did not affect the peak positions and shapes of anatase TiO₂ significantly, but the intensity of the peaks was changed. The Raman scattering effect of Ag-Fe₃O₄-SiO₂-TiO₂ was enhanced compared with that of N-Fe₃O₄-SiO₂-TiO₂ composites. This is mainly due to the fact that Ag adsorption on the TiO₂ surface enhances the electric field strength between the two, which increases the molecular polarisation and makes the Raman signal enhancement more obvious. In addition, the Ag/N-Fe₃O₄-SiO₂-TiO₂ Raman scattering effect is the strongest, which may be conducive to the enhancement of the photocatalytic activity of doubly doped TiO₂. The analytical results of Raman spectra fully proved that Ag and N have been successfully doped into TiO₂.
基于光与材料内化学键之间相互作用的拉曼光谱可以提供有关样品化学结构、结晶度等的重要信息。图 9 显示了不同类型光催化剂样品的拉曼光谱。据报道，锐钛矿型 TiO 2 的拉曼位移波数分别为 399、515 和 639 cm⁻¹，相应的振动模式为 B_1g、A_1g 和 B_2g。图中 Fe₃O_4-SiO _2-TiO ₂ 复合材料的拉曼位移波数分别为 395.00、508.78 和 628.35 cm⁻¹，可以很好地对应。Ag 和 N 的掺杂对锐钛矿型 TiO₂ 的峰位和形状没有显著影响，但峰的强度发生了变化。与 N-Fe₃O_4-SiO 2-TiO 2 复合材料相比，Ag-Fe₃O_4-SiO _2-TiO ₂ 的拉曼散射效应增强。这主要是由于 TiO₂ 表面的 Ag 吸附增强了两者之间的电场强度，从而增加了分子极化，使拉曼信号增强更加明显。此外，Ag/N-Fe₃O 4-SiO 2-TiO ₂ 拉曼散射效应最强，可能有利于增强双掺杂 TiO₂ 的光催化活性。拉曼光谱分析结果充分证明 Ag 和 N 已成功掺杂到 TiO₂ 中。

3.8. BET analysis 3.8. BET 分析

Fig. 10 shows the variation of nitrogen adsorption desorption isotherms for Fe₃O₄-SiO₂-TiO₂, Ag-Fe₃O₄-SiO₂-TiO₂, N-Fe₃O₄-SiO₂-TiO₂ and Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalysts. Where Ads represents the adsorption isotherm of the sample and Des represents the desorption isotherm of the sample. According to the five isotherm types classified by Brunauer's, it can be seen that some of the adsorption and desorption isotherms do not overlap in Fig. 10d, forming an obvious hysteresis loop, which belongs to the typical type IV isotherm. This strongly proves the existence of abundant mesoporous structure in TiO₂ modified by Ag or N. In addition, the images show that the Ag/N-Fe₃O₄-SiO₂-TiO₂ material combines some of the corresponding curve features of Ag-Fe₃O₄-SiO₂-TiO₂ and N-Fe₃O4-SiO₂-TiO₂ materials, which is an important evidence of the successful preparation of Ag/N-Fe₃O₄-SiO₂-TiO₂ composites. Table 3 shows how the pore structures of the four samples were analysed and evaluated in order to further understand the relationship between the adsorption capacity and light absorption properties of each sample and the photocatalytic performance. We found that the specific surface area and pore volume of the Ag/N-Fe₃O₄-SiO₂-TiO₂ material were significantly increased relative to Fe₃O₄-SiO₂-TiO₂, Ag-Fe₃O₄-SiO₂-TiO₂ and N-Fe₃O₄-SiO₂-TiO₂, which corresponded well to the SEM images of different types of photocatalysts. The well-ordered pore structure can produce stronger adsorption capacity for microorganisms in ballast water, and the photocatalytic performance is enhanced accordingly. More importantly, the more excellent pore structure of mesoporous Ag/N-Fe₃O₄-SiO₂-TiO₂ facilitates the movement of electrons along the pore wall and promotes the rapid electron-hole migration; while the larger specific surface area can expose more active sites to promote the absorption of incident light by the photocatalysts, both of which dramatically improve the photocatalytic activity of the composites.
图 10 显示了 Fe ₃O_4-SiO _2-TiO ₂、Ag-Fe₃O_4-SiO _2-TiO ₂、N-Fe₃O_4-SiO _2-TiO ₂ 和 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化剂的氮吸附脱附等温线的变化。其中 Ads 表示样品的吸附等温线，Des 表示样品的解吸等温线。根据 Brunauer's 分类的 5 种等温线类型，可以看出图 10 d 中部分吸附和解吸等温线不重叠，形成明显的磁滞回线，属于典型的 IV 型等温线。这有力地证明了 Ag 或 N 修饰的 TiO 2 中存在丰富的介孔结构。此外，图像显示，Ag/N-Fe₃O_4-SiO _2-TiO ₂ 材料结合了 Ag-Fe₃O_4-SiO _2-TiO ₂ 和 N-Fe₃O4-SiO_2-TiO ₂ 材料的一些相应曲线特征，是成功制备 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 复合材料的重要证据。表 3 显示了如何分析和评估四个样品的孔结构，以进一步了解每个样品的吸附能力和光吸收特性与光催化性能之间的关系。我们发现，Ag/N-Fe ₃O_4-SiO _2-TiO ₂ 材料的比表面积和孔体积相对于 Fe₃O_4-SiO _2-TiO ₂、Ag-Fe₃O_4-SiO _2-TiO ₂ 和 N-Fe₃O_4-SiO _2-TiO ₂ 显著增加，这与不同类型光催化剂的 SEM 图像非常吻合。井然有序的孔隙结构可以对压载水中微生物产生更强的吸附能力，光催化性能也相应增强。更重要的是，介孔 Ag/N-Fe₃O 4-SiO_2-TiO ₂ 更优异的孔结构促进了电子沿孔壁的运动，促进了电子-空穴的快速迁移;而较大的比表面积可以暴露更多的活性位点，促进光催化剂对入射光的吸收，这两者都显着提高了复合材料的光催化活性。

Table 3. Specific surface area, pore size and pore volume of different samples.
表 3.不同样品的比表面积、孔径和孔体积。

Samples 样品	Surface area (m²/g) 表面积（m²/g）	Pore volume (cm³/g) 孔隙体积（cm³/g）	Pore size (nm) 孔径（nm）
Fe₃O₄-SiO₂-TiO₂ 铁 ₃O_4-SiO _2-TiO ₂	35.3712	0.110880	12.1477
N-Fe₃O₄-SiO₂-TiO₂ 正铁 ₃O_4-SiO _2-TiO ₂	63.6176	0.099500	6.0153
Ag-Fe₃O₄-SiO₂-TiO₂ 银-铁 ₃O_4-SiO _2-TiO ₂	80.8558	0.147570	7.0480
Ag/N-Fe₃O₄-SiO₂-TiO₂ 银/N-铁 ₃O_4-SiO _2-TiO ₂	109.0411	0.200680	7.1382

3.9. Changes in superoxide dismutase content
3.9. 超氧化物歧化酶含量的变化

When an organism is subjected to adversity stress, it generates and accumulates large amounts of reactive oxygen species, leading to physiological senescence or death. Superoxide dismutase (SOD) can specifically scavenge the cellular damage caused by reactive oxygen species and is an important indicator of the degree of cellular damage in an organism. In order to investigate the specific causes of accelerated microbial death under UVA/UVC_LED photocatalytic conditions, the changes in SOD activity of Karenia mikimotoi and Escherichia coli were determined under different treatment conditions (Fig. 11). The SOD content was relatively high in the untreated samples (6.581 U/mL for Karenia mikimotoi and 6.315 U/mL for Escherichia coli), and the SOD activity of the microorganisms gradually decreased with the increase of UV irradiation time. At 240 s, the SOD activity of Karenia mikimotoi in the UVA/UVC_LED + Ag/N-Fe₃O₄-SiO₂-TiO₂, UVA/UVC_LED + Ag-Fe₃O₄-SiO₂-TiO₂, and UVA/UVC_LED + N-Fe₃O₄-SiO₂-TiO₂ systems decreased by 88.21 %, 81.26 %, and 64.63 %, and SOD activity of Escherichia coli decreased by 89.21 %, 81.08 % and 74.67 %, respectively, and always the fastest rate of decrease was observed in the UVA/UVC_LED + Ag/N-Fe₃O₄-SiO₂-TiO₂ treatment system. In general, reactive radicals play a decisive role in photocatalytic degradation of pollutants and inactivation of microorganisms. Under visible light irradiation, the Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalyst was energetically excited to generate electrons and holes, where the presence of Ag and N facilitated the transport of photogenerated carriers. In the presence of electrons, O₂ was reduced to ·O₂₋, while holes reacted with H₂O to form ·OH. Researchers have demonstrated that the photocatalytic reaction of modified TiO₂ involves the participation of various free radicals by free radical trapping experiments, whereas hydroxyl and superoxide radicals play the most important role as the reactive substances in the system [76,77]. Ultimately, under the main effect of hydroxyl and superoxide radicals, the cell structure of microorganisms such as Karenia mikimotoi and Escherichia coli is irreversibly damaged through direct damage or a series of chain reactions. This greatly inhibited the ability of microbial cells to take up specific catalytic metal ions (Cu²⁺, Zn²⁺, Mn²⁺, Fe²⁺) necessary for the synthesis of SOD, further enhancing the toxic effects of the active substances on the cells [78]. It was observed by SEM and TEM that Ag/N-Fe₃O₄-SiO₂-TiO₂ had better surface morphology and ordered pore structure, which were more favourable for the rapid electron-hole migration, and the larger specific surface area could more effectively adsorb microorganisms firmly on the TiO₂ surface. This not only generates a greater number of active radicals during the photocatalytic process, but also accelerates their contact rate with the microorganisms, minimising their rapid inactivation in water. More importantly, the greater number of active radicals can inhibit SOD activity in microbial cells to a greater extent, which significantly improves the antagonistic effect between the two, and ultimately improves the overall inactivation efficiency of the system. This is in line with the previous findings produced by UVA/UVC_LED combined with the optimal modification ratio photocatalyst.
当生物体受到逆境压力时，它会产生并积累大量的活性氧，导致生理衰老或死亡。超氧化物歧化酶（SOD）可以特异性清除活性氧引起的细胞损伤，是生物体细胞损伤程度的重要指标。为了探究 UVA/UVC LED 光催化条件下微生物加速死亡的具体原因，测定了不同处理条件下 Karenia mikimotoi 和大肠杆菌 SOD 活性的变化（图 11）。未处理样品的 SOD 含量相对较高（Karenia mikimoşi 为 6.581 U/mL， 大肠埃希菌为 6.315 U/mL），并且随着紫外线照射时间的增加，微生物的 SOD 活性逐渐降低。在 240 s 时，UVA/UVC_LED + Ag/N-Fe₃O_4-SiO _2-TiO ₂、UVA/UVC_LED + Ag-Fe₃O_4-SiO _2-TiO ₂ 和 UVA/UVC_LED + N-Fe₃O_4-SiO _2-TiO ₂ 体系中 Karenia mikimotoi 的 SOD 活性降低了 88.21 %。 大肠埃希菌的 SOD 活性分别下降了 81.26 % 和 64.63 %，SOD 活性分别下降了 89.21 %、81.08 % 和 74.67 %，并且在 UVA/UVC_LED + Ag/N-Fe₃O_4-SiO _2-TiO ₂ 处理系统中始终观察到最快的下降速度。一般来说，反应性自由基在光催化降解污染物和灭活微生物中起决定性作用。在可见光照射下，Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化剂被能量激发产生电子和空穴，其中 Ag 和 N 的存在促进了光生载流子的传输。在电子存在下，O₂ 被还原为 ·O₂₋，而空穴与 H₂O 反应形成 ·哦。研究人员已经证明，改性 TiO₂ 的光催化反应涉及各种自由基通过自由基捕获实验的参与，而羟基和超氧自由基作为系统中的反应物质起着最重要的作用[76,77 ].最终，在羟基和超氧自由基的主作用下，Karenia mikimotoi 和 Escherichia coli 等微生物的细胞结构通过直接损伤或一系列连锁反应受到不可逆的破坏。这极大地抑制了微生物细胞吸收合成 SOD 所需的特定催化金属离子（Cu²⁺、Zn²⁺、Mn²⁺、Fe²⁺）的能力，进一步增强了活性物质对细胞的毒性作用[78]。 SEM 和 TEM 观察到 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 具有较好的表面形貌和有序的孔结构，更有利于电子-空穴的快速迁移，较大的比表面积可以更有效地将微生物牢牢吸附在 TiO₂ 上表面。这不仅在光催化过程中产生更多的活性自由基，而且加快了它们与微生物的接触速度，最大限度地减少了它们在水中的快速灭活。更重要的是，活性自由基数量的增加可以在更大程度上抑制微生物细胞中的 SOD 活性，从而显著提高两者之间的拮抗作用，最终提高系统的整体灭活效率。这与 UVA/UVC_LED 结合最佳改性比光催化剂产生的先前发现一致。

3.10. Mechanical analysis of inactivity
3.10. 不活动的机械分析

Fig. 12 represents the results of the inactivation treatment of Karenia mikimotoi and Escherichia coli by UVA/UVC_LED combined with the optimal modification ratio photocatalysts, and the inactivation kinetics curves were obtained by fitting the experimental data using the Chick-Watson model, the Hom model and the Biphasic model. The results showed (Table 4, Table 5) that the first-order linear curves formed by fitting the Chick-Watson model (R²: 0.46371–0.70893, RMSE: 0.15415–0.60964) were significantly different from the experimental data. The Hom model (R²: 0.96257–0.99305, RMSE: 0.04691–0.09741) took into account the actual situation of the non-linear relationship between the inactivation time and microbial survival, and could be fitted to the phenomenon that the logarithmic inactivation rate of microorganisms increased slowly with the sterilisation time from 60 to 240 s according to the value of the constant h. However, the optimal fitted curves still had a small part of the differences. Among the three models, the Biphasic model was the best fitted model with the highest accuracy to the experimental values (R²: 0.99571–0.99926, RMSE: 0.01022–0.03926), and the survival of the target microorganisms during the complete inactivation process (0–240 s) was highly in accordance with the predicted values of this model. The reason for this is that the same population of target microorganisms may exist in two different types of subpopulations, with subpopulations having different sensitivities to unfavourable environments, which are inactivated at different kinetic rates (k₁ > k₂) [42,43,46]. The inactivation curves of sensitive populations that are not resistant to UV show a linear and rapid growth phenomenon, and the inactivation curves of resistant populations that are resistant to UV show a non-linear and slow-growing tailing phenomenon. In addition, some microorganisms may have the ability to spontaneously repair UV damage to their nucleic acids, and may become tolerant to UV radiation, so that the absorbed dose of radiation exceeds a threshold before showing an inactivation response, which ultimately leads to a slow decrease in the inactivation rate with disinfection time [43]. Therefore, the Chick-Watson model is not applicable to the actual situation of catalytic inactivation by multi-band UV light, and the Biphasic model, which fits the curve most in line with the experimental values, can be used to predict the inactivation effect of multi-band UV light on microorganisms in ballast water in different time periods.
图 12 表示 UVA/UVC_LED 结合最佳修饰比例光催化剂对 Karenia mikimoto 和大肠杆菌进行灭活处理的结果，使用 Chick-Watson 模型、Hom 模型和 Biphasic 模型拟合实验数据得到灭活动力学曲线。结果表明（表 4、表 5）拟合 Chick-Watson 模型形成的一阶线性曲线（R²： 0.46371–0.70893， RMSE： 0.15415–0.60964）与实验数据显著不同。Hom 模型（R²： 0.96257–0.99305， RMSE： 0.04691–0.09741）考虑了灭活时间与微生物存活率非线性关系的实际情况，可以拟合到微生物对数灭活率随杀菌时间 60 —240 s 缓慢增加的现象，根据常数 h 的值。然而，最佳拟合曲线仍然有一小部分差异。在这三种模型中，双相模型是拟合最好的模型，对实验值的准确性最高（R²： 0.99571–0.99926， RMSE： 0.01022–0.03926），并且在完全灭活过程中目标微生物的存活率（0–240 s）与该模型的预测值高度一致。其原因是相同的目标微生物种群可能存在于两种不同类型的亚群中，亚群对不利环境具有不同的敏感性，这些环境以不同的动力学速率（k₁ > k₂）失活[42,43,46 ].对 UV 不抗的敏感群体的失活曲线表现出线性和快速的生长现象，对 UV 有抗性的抗性群体的失活曲线表现出非线性和缓慢生长的拖尾现象。此外，一些微生物可能具有自发修复紫外线对其核酸损伤的能力，并可能变得耐受紫外线辐射，以至于吸收的辐射剂量超过阈值后才表现出灭活反应，最终导致灭活速率随消毒时间缓慢下降 [43].因此，Chick-Watson 模型不适用于多波段紫外光催化灭活的实际情况，而曲线拟合最符合实验值的双相模型可用于预测多波段紫外光在不同时段对压载水中微生物的灭活效果。

Table 4. Kinetic models and parameters of Karenia mikimotoi.
表 4.Karenia mikimotoi 的动力学模型和参数。

Modalities of handling 处理方式	Models 模型	k₁	k₂	h	p	R²	RMSD
UVA/UVC_LED + 1.5%Ag-Fe₃O₄-SiO₂-TiO₂ UVA/UVC_LED + 1.5%银-铁 ₃O_4-SiO _2-TiO ₂	Chick-Watson 小鸡-沃森	−0.00436	–	–	–	0.57589	0.18015
	Hom 磡	−0.10108	–	0.39208	–	0.97483	0.04691
	Biphasic 两相	0.03545	0.00199	–	0.76127	0.99713	0.01712
UVA/UVC_LED + 3 %N-Fe₃O₄-SiO₂-TiO₂ UVA/UVC_LED + 3 %N-Fe₃O 4-SiO 2-TiO ₂	Chick-Watson 小鸡-沃森	−0.0036	–	–	–	0.55109	0.15415
	Hom 磡	−0.08556	–	0.38737	–	0.96257	0.04759
	Biphasic 两相	0.02828	0.00056	–	0.75472	0.99852	0.01022
UVA/UVC_LED + 1.5%Ag/3%N-Fe₃O₄-SiO₂-TiO₂ UVA/UVC_LED + 1.5%Ag/3%N-Fe₃O_4-SiO _2-TiO ₂	Chick-Watson 小鸡-沃森	−0.00743	–	–	–	0.48496	0.32722
	Hom 磡	−0.21882	–	0.34536	–	0.98643	0.05677
	Biphasic 两相	0.05975	0.00465	–	0.88517	0.99926	0.01429

Table 5. Kinetic models and parameters of Escherichia coli.
表 5. 大肠杆菌的动力学模型和参数。

Modalities of handling 处理方式	Models 模型	k₁	k₂	h	p	R²	RMSD
UVA/UVC_LED + 1.5%Ag-Fe₃O₄-SiO₂-TiO₂ UVA/UVC_LED + 1.5%银-铁 ₃O_4-SiO _2-TiO ₂	Chick-Watson 小鸡-沃森	−0.00933	–	–	–	0.53691	0.39882
	Hom 磡	−0.23814	–	0.37347	–	0.97583	0.09741
	Biphasic 两相	0.0593	0.00526	–	0.94155	0.99676	0.03852
UVA/UVC_LED + 3 %N-Fe₃O₄-SiO₂-TiO₂ UVA/UVC_LED + 3 %N-Fe₃O 4-SiO 2-TiO ₂	Chick-Watson 小鸡-沃森	−0.00659	–	–	–	0.70893	0.23787
	Hom 磡	−0.1	–	0.47488	–	0.96441	0.08892
	Biphasic 两相	0.02957	0.00011	–	0.94199	0.99571	0.03335
UVA/UVC_LED + 1.5%Ag/3%N- Fe₃O₄-SiO₂-TiO₂ UVA/UVC_LED + 1.5%Ag/3%N- Fe₃O_4-SiO _2-TiO ₂	Chick-Watson 小鸡-沃森	−0.01373	–	–	–	0.46371	0.60964
	Hom 磡	−0.42894	–	0.33358	–	0.99305	0.07419
	Biphasic 两相	0.09973	0.00995	–	0.97596	0.99833	0.03926

4. Conclusions 4. 结论

UVA/UVC_LED + Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalytic technology can effectively remove harmful aquatic microorganisms such as Karenia mikimotoi and Escherichia coli in ballast water, and solve the problems of high energy consumption of mercury lamp source and incomplete inhibition of microbial resurrection in traditional ballast water treatment technology. It was found that the Ag-modified and N-modified nano-TiO₂ could significantly improve its own photocatalytic activity, and the inactivation efficiencies of Karenia mikimotoi and Escherichia coli were the greatest at the Ag/N double modification ratios of 1.5 % and 3 % with 1.421 log and 2.636 log, respectively, which were higher than those of the traditional unmodified TiO₂. At this time, the superoxide dismutase (SOD) activity (0.776 U/mL for Karenia mikimotoi and 0.681 U/mL for Escherichia coli) was correspondingly kept at the lowest level. The optimal use of Ag and N modified TiO₂ photocatalyst was 500 mg/L. The UV photocatalytic performance of the catalyst remained above 90 % after 6 cycles, which was 8.76 % lower than that of the initial use, and the recovery efficiency was still up to 95.75 %, which was only 4.25 % lower than that of the initial use. This indicates that the Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalysts have stable photocatalytic performance and good magnetic separation performance. The Biphasic model is the most suitable model for the actual situation of multiband UV photocatalytic inactivation, and it is used to predict the inactivation effect of multiband UV photocatalysis on microorganisms in ballast water in different time periods with high accuracy. Overall, the results demonstrated that the UVA/UVC_LED + Ag/N-Fe₃O₄-SiO₂-TiO₂ photocatalysis is competitive in solving the invasion of ex-situ marine organisms in ballast water, and provides a new strategy for marine ecological environment management.
UVA/UVC_LED + Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化技术可有效去除压载水中克伦氏菌 、大肠杆菌等有害水生微生物，解决传统压载水处理中汞灯源能耗高、微生物复活抑制不完全等问题科技。结果表明，Ag 改性和 N 改性纳米 TiO₂ 能显著提高其自身的光催化活性，其中 Karenia mikimotoi 和大肠杆菌的灭活效率最高，Ag/N 双改性比分别为 1.5 % 和 3 %，分别为 1.421 log 和 2.636 log，高于传统的未改性 TiO₂.此时，超氧化物歧化酶（SOD）活性（Karenia mikimomotoi 为 0.776 U/mL， 大肠杆菌为 0.681 U/mL）相应地保持在最低水平。Ag 和 N 改性 TiO₂ 光催化剂的最佳使用量为 500 mg/L。催化剂的紫外光催化性能在 6 次循环后保持在 90 % 以上，比初次使用低 8.76 %，回收效率仍高达 95.75 %，仅比初次使用低 4.25 %。这表明 Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化剂具有稳定的光催化性能和良好的磁分离性能。双相模型是最适合多波段紫外光催化灭活实际情况的模型，用于预测多波段紫外光催化在不同时段对压载水中微生物的灭活效果，精度高。总体而言，结果表明，UVA/UVC_LED + Ag/N-Fe₃O_4-SiO _2-TiO ₂ 光催化在解决压载水中异地海洋生物的入侵方面具有竞争力，为海洋生态环境管理提供了新的策略。

CRediT authorship contribution statement
CRediT 作者贡献声明

Conceptualization, J.Z. and Z.L.; methodology, J.Z.; formal analysis, H.S., J.Y. and J.Z.; investigation, C.Z.; resources, Y.S.; data curation, Q.L. and F.D.; writing—original draft preparation, J.Z.; writing—review and editing, H.S., J.Z. and J.Y.; visualization, B.Z. and C.L.; funding acquisition, Y.S. and Z.L. All authors have read and agreed to the published version of the manuscript.
概念化，J.Z. 和 Z.L.;方法论，J.Z.;形式分析，H.S.、J.Y. 和 J.Z.;调查，C.Z.;资源，Y.S.;数据管理，Q.L. 和 F.D.;写作——原始草稿准备，J.Z.;写作——审查和编辑、H.S.、J.Z. 和 J.Y.;可视化，B.Z. 和 C.L.;资金收购，Y.S. 和 Z.L.所有作者均已阅读并同意手稿的已发表版本。

Funding 资金

This research was financially supported by the National Natural Science Foundation of China (52171347), the Natural Science Foundation of Shandong Province (ZR2023QE073), the Natural Science Foundation of Heilongjiang Province (LH2023E070) and the Qingdao Natural Science Foundation (23-2-1-97-zyyd-jch).
这项研究得到了中国国家自然科学基金（52171347）、山东省自然科学基金（ZR2023QE073）、黑龙江省自然科学基金（LH2023E070）和青岛自然科学基金（23-2-1-97-zyyd-jch）的财政支持。

Institutional review board statement
机构审查委员会声明

Not applicable. 不適用。

Informed consent statement
知情同意书

Not applicable. 不適用。

Declaration of competing interest
利益争夺声明

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
作者声明，他们没有已知的竞争性经济利益或个人关系，这些利益或个人关系似乎可能会影响本文报告的工作。

Acknowledgments 确认

We are deeply grateful to the editors and reviewers for their guiding suggestions and other efforts to improve this manuscript.
我们非常感谢编辑和审稿人为改进本稿件提出的指导性建议和其他努力。

Data availability 数据可用性

Data are available from the corresponding author upon reasonable request.
如有合理要求，可从通讯作者处获得数据。

References

[1]
L.A. Drake, M.A. Doblin, F.C. Dobbs
Potential microbial bioinvasions via ships' ballast water, sediment, and biofilm
Mar. Pollut. Bull., 55 (2007), pp. 333-341
View PDF View article View in Scopus Google Scholar
[2]
B.Y. Lv, J.H. Shi, T. Li, L.L. Ren, W. Tian, X.L. Lu, Y.C. Han, Y.X. Cui, T. Jiang
Deciphering the characterization, ecological function and assembly processes of bacterial communities in ship ballast water and sediments
Sci. Total Environ., 816 (2022), Article 152721
View PDF View article View in Scopus Google Scholar
[3]
E. Tsolaki, E. Diamadopoulos
Technologies for ballast water treatment: a review
J. Chem. Technol. Biotechnol., 85 (2010), pp. 19-32
Crossref View in Scopus Google Scholar
[4]
R. Sommer, A. Cabaj, G. Hirschmann, T. Haider
Disinfection of drinking water by UV irradiation: basic principles - specific requirements - international implementations
Ozone Sci. Eng., 30 (2008), pp. 43-48
Crossref View in Scopus Google Scholar
[5]
W. Luo, T. Li, Y.D. Li, H.J. Wang, Y. Yuan, S.F. Liu, W.Y. Wang, Q. Wang, J.J. Kang, X.Q. Wang
Watts-level ultraviolet-C LED integrated light sources for efficient surface and air sterilization
J. Semicond., 43 (2022), Article 072301
Crossref View in Scopus Google Scholar
[6]
A.B. Soro, S. Shokri, I. Nicolau-Lapena, D. Ekhlas, C.M. Burgess, P. Whyte, D.J. Bolton, P. Bourke, B.K. Tiwari
Current challenges in the application of the UV-LED technology for food decontamination
Trends Food Sci. Technol., 131 (2022), pp. 264-276
Google Scholar
[7]
V. Baldasso, H. Lubarsky, N. Pichel, A. Turolla, M. Antonelli, M. Hincapie, L. Botero, F. Reygadas, A. Galdos-Balzategui, J.A. Byrne, P. Fernandez-Ibanez
UVC inactivation of MS2-phage in drinking water-modelling and field testing
Water Res., 203 (2021), Article 117496
View PDF View article View in Scopus Google Scholar
[8]
K.O. Maloney, D.P. Morris, C.O. Moses, C.L. Osburn
The role of iron and dissolved organic carbon in the absorption of ultraviolet radiation in humic lake water
Biogeochemistry, 75 (2005), pp. 393-407
Crossref View in Scopus Google Scholar
[9]
K. Song, M. Mohseni, F. Taghipour
Mechanisms investigation on bacterial inactivation through combinations of UV wavelengths
Water Res., 163 (2019), Article 114875
View PDF View article View in Scopus Google Scholar
[10]
R.P. Sinha, D.P. Hader
UV-induced DNA damage and repair: a review
Photochem. Photobiol. Sci., 1 (2022), pp. 225-236
Crossref Google Scholar
[11]
M. Martin-Somer, C. Pablos, C. Adan, R. van Grieken, J. Marugan
A review on LED technology in water photodisinfection
Sci. Total Environ., 885 (2023), Article 163963
View PDF View article View in Scopus Google Scholar
[12]
A.C. Chevremont, J.L. Boudenne, B. Coulomb, A.M. Farnet
Impact of watering with UV-LED-treated wastewater on microbial and physico-chemical parameters of soil
Water Res., 47 (2013), pp. 1971-1982
View PDF View article View in Scopus Google Scholar
[13]
J. Arun, S. Nachiappan, G. Rangarajan, R.P. Alagappan, K.P. Gopinath, E. Lichtfouse
Synthesis and application of titanium dioxide photocatalysis for energy, decontamination and viral disinfection: a review
Environ. Chem. Lett., 21 (2023), pp. 339-362
Crossref View in Scopus Google Scholar
[14]
H.M. Yadav, J.S. Kim, S.H. Pawar
Developments in photocatalytic antibacterial activity of nano TiO2: a review
Korean J. Chem. Eng., 33 (2016), pp. 1989-1998
Crossref View in Scopus Google Scholar
[15]
W.A. Daoud, J.H. Xin, Y.H. Zhang
Surface functionalization of cellulose fibers with titanium dioxide nanoparticles and their combined bactericidal activities
Surf. Sci., 599 (2005), pp. 69-75
View PDF View article View in Scopus Google Scholar
[16]
M. Cho, H. Chung, W. Choi, J. Yoon
Linear correlation between inactivation of E-coli and OH radical concentration in TiO2 photocatalytic disinfection
Water Res., 38 (2004), pp. 1069-1077
View PDF View article View in Scopus Google Scholar
[17]
J. Zhao, V. Krishna, B. Hua, B. Moudgil, B. Koopman
Effect of UVA irradiance on photocatalytic and UVA inactivation of Bacillus cereus spores
J. Photochem. Photobiol. B, 94 (2009), pp. 96-100
View PDF View article Google Scholar
[18]
J. Garcia-Garay, A. Franco-Herrera, F. Machuca-Martinez
Zooplankton sensitivity and phytoplankton regrowth for ballast water treatment with advanced oxidation processes
Environ. Sci. Pollut. Res., 25 (2018), pp. 35008-35014
Crossref View in Scopus Google Scholar
[19]
Z. Lu, K. Zhang, X.L. Liu, Y. Shi
High efficiency inactivation of microalgae in ballast water by a new proposed dual-wave UV-photocatalysis system (UVA/UVC-TiO2)
Environ. Sci. Pollut. Res., 26 (2019), pp. 7785-7792
Crossref View in Scopus Google Scholar
[20]
J. Bogdan, J. Zarzynska, J. Plawinska-Czarnak
Comparison of infectious agents susceptibility to photocatalytic effects of nanosized titanium and zinc oxides: a practical approach
Nanoscale Res. Lett., 10 (2015), p. 309
View in Scopus Google Scholar
[21]
P. Akhter, A. Arshad, A. Saleem, M. Hussain
Recent development in non-metal-doped titanium dioxide photocatalysts for different dyes degradation and the study of their strategic factors: a review
Catalysts, 12 (2022), p. 1331
Crossref View in Scopus Google Scholar
[22]
V. Rehacek, I. Hotovy
Deposition of gold nanoparticles from colloid on TiO2 surface
J. Electr. Eng., 68 (2017), pp. 487-491
Crossref View in Scopus Google Scholar
[23]
J. Singh, B. Satpati, S. Mohapatra
Structural, optical and plasmonic properties of Ag-TiO2 hybrid plasmonic nanostructures with enhanced photocatalytic activity
Plasmonics, 12 (2017), pp. 877-888
Crossref View in Scopus Google Scholar
[24]
S.W. Leong, A. Razmjou, K. Wang, K. Hapgood, X.W. Zhang, H.T. Wang
TiO2 based photocatalytic membranes: a review
J. Membr. Sci., 472 (2014), pp. 167-184
View PDF View article View in Scopus Google Scholar
[25]
X.J. Xiao, J.L. Tu, Z.M. Liu, L. Liu
First principles study of the electronic and optical properties of high-valence transition metal-doped anatase titanium dioxide
Mater. Werkst., 53 (2022), pp. 1551-1560
Crossref View in Scopus Google Scholar
[26]
R.D. Liu, H. Li, L.B. Duan, H. Shen, Y.Y. Zhang, X.R. Zhao
In situ synthesis and enhanced visible light photocatalytic activity of C-TiO2 microspheres/carbon quantum dots
Ceram. Int., 43 (2017), pp. 8648-8654
View PDF View article View in Scopus Google Scholar
[27]
J. Musial, A. Belet, D.T. Mlynarczyk, M. Kryjewski, T. Goslinski, S.D. Lambert, D. Poelman, B.J. Stanisz
Nanocomposites of titanium dioxide and peripherally substituted phthalocyanines for the photocatalytic degradation of sulfamethoxazole
Nanomaterials, 12 (2022), p. 3279
Crossref View in Scopus Google Scholar
[28]
H.M. Yadav, S.V. Otari, V.B. Koli, S.S. Mali, C.K. Hong, S.H. Pawar, S.D. Delekar
Preparation and characterization of copper-doped anatase TiO2 nanoparticles with visible light photocatalytic antibacterial activity
J. Photochem. Photobiol., A, 280 (2014), pp. 32-38
View PDF View article View in Scopus Google Scholar
[29]
H.M. Yadav, S.V. Otari, R.A. Bohara, S.S. Mali, S.H. Pawar, S.D. Delekar
Synthesis and visible light photocatalytic antibacterial activity of nickel-doped TiO2 nanoparticles against Gram-positive and Gram-negative bacteria
J. Photochem. Photobiol., A, 294 (2014), pp. 130-136
View PDF View article View in Scopus Google Scholar
[30]
F. Sayilkan, M. Asilturk, N. Kiraz, E. Burunkaya, E. Arpac, H. Sayilkan
Photocatalytic antibacterial performance of Sn4+-doped TiO2 thin films on glass substrate
J. Hazard. Mater., 162 (2009), pp. 1309-1316
View PDF View article View in Scopus Google Scholar
[31]
H.M.M. Ibrahim
Photocatalytic degradation of methylene blue and inactivation of pathogenic bacteria using silver nanoparticles modified titanium dioxide thin films
World J. Microbiol. Biotechnol., 31 (2015), pp. 1049-1060
Crossref View in Scopus Google Scholar
[32]
L. Caballero, K.A. Whitehead, N.S. Allen, J. Verran
Photocatalytic inactivation of Escherichia coli using doped titanium dioxide under fluorescent irradiation
J. Photochem. Photobiol., A, 276 (2014), pp. 50-57
View PDF View article View in Scopus Google Scholar
[33]
L. Armelao, D. Barreca, G. Bottaro, A. Gasparotto, C. Maccato, C. Maragno, E. Tondello, U.L. Stangar, M. Bergant, D. Mahne
Photocatalytic and antibacterial activity of TiO2 and Au/TiO2 nanosystems
Nanotechnology, 18 (2007), Article 375709
Crossref View in Scopus Google Scholar
[34]
N.C. Raut, T. Mathews, P.K. Ajikumar, R.P. George, S. Dash, A.K. Tyagi
Sunlight active antibacterial nanostructured N-doped TiO2 thin films synthesized by an ultrasonic spray pyrolysis technique
RSC Adv., 2 (2012), pp. 10639-10647
Crossref View in Scopus Google Scholar
[35]
H.U. Lee, S.C. Lee, S.H. Choi, B. Son, S.J. Lee, H.J. Kim, J. Lee
Highly visible-light active nanoporous TiO2 photocatalysts for efficient solar photocatalytic applications
Appl. Catal. B, 129 (2013), pp. 106-113
View PDF View article View in Scopus Google Scholar
[36]
B.F. Xin, Z.Y. Ren, P. Wang, J. Liu, L.Q. Jing, H.G. Fu
Study on the mechanisms of photoinduced carriers separation and recombination for Fe3+-TiO2 photocatalysts
Appl. Surf. Sci., 253 (2007), pp. 4390-4395
View PDF View article View in Scopus Google Scholar
[37]
X.X. Wang, Y.L. Huang, K. Zhang, Y. Shi, Z. Lu, Y.H. Wang
Inactivation effect and mechanisms of combined ultraviolet and metal-doped nano-TiO2 on treating Escherichia coli and Enterococci in ballast water
Environ. Sci. Pollut. Res., 27 (2020), pp. 40286-40295
Crossref View in Scopus Google Scholar
[38]
Y. Liu, J. Huang, X.H. Feng, H. Li
Thermal-sprayed photocatalytic coatings for biocidal applications: a review
J. Therm. Spray Technol., 30 (2021), pp. 1-24
Google Scholar
[39]
X.J. Zhang, W.B. Chen, Z.D. Lin, J.C. Shen
Photocatalytic degradation of a methyl orange wastewater solution using titanium dioxide loaded on bacterial cellulose
Synth. React. Inorg., Met.-Org., Nano-Met. Chem., 41 (2011), pp. 1141-1147
Crossref View in Scopus Google Scholar
[40]
H.B. Yao, M.H. Fan, Y.J. Wang, G.S. Luo, W.Y. Fei
Magnetic titanium dioxide based nanomaterials: synthesis, characteristics, and photocatalytic application in pollutant degradation
J. Mater. Chem. A, 3 (2015), pp. 17511-17524
View in Scopus Google Scholar
[41]
I. Shtein, B. Bar-On, Z.A. Popper
Plant and algal structure: from cell walls to biomechanical function
Physiol. Plant., 164 (2018), pp. 56-66
Crossref View in Scopus Google Scholar
[42]
J. Rodriguez-Chueca, M.P. Ormad, R. Mosteo, J.L. Ovelleiro
Kinetic modeling of Escherichia coli and Enterococcus sp. inactivation in wastewater treatment by photo-Fenton and H2O2/UV-vis processes
Chem. Eng. Sci., 138 (2015), pp. 730-740
View PDF View article View in Scopus Google Scholar
[43]
J.J. Velez-Colmenares, A. Acevedo, E. Nebot
Effect of recirculation and initial concentration of microorganisms on the disinfection kinetics of Escherichia coli
Desalination, 280 (2011), pp. 20-26
View PDF View article View in Scopus Google Scholar
[44]
J. Marugan, R. van Grieken, C. Sordo, C. Cruz
Kinetics of the photocatalytic disinfection of Escherichia coli suspensions
Appl. Catal. B, 82 (2008), pp. 27-36
View PDF View article View in Scopus Google Scholar
[45]
E.N. Sanz, I.S. Davila, J.A.A. Balao, J.M.Q. Alonso
Modelling of reactivation after UV disinfection: effect of UV-C dose on subsequent photoreactivation and dark repair
Water Res., 41 (2007), pp. 3141-3151
Google Scholar
[46]
K. Fitzhenry, E. Clifford, N. Rowan, A.V. del Rio
Bacterial inactivation, photoreactivation and dark repair post flow-through pulsed UV disinfection
J. Water Process Eng., 41 (2021), Article 102070
View PDF View article View in Scopus Google Scholar
[47]
I. Salcedo, J.A. Andrade, J.M. Quiroga, E. Nebot
Photoreactivation and dark repair in UV-treated microorganisms: effect of temperature
Appl. Environ. Microbiol., 73 (2007), pp. 1594-1600
View in Scopus Google Scholar
[48]
H.T. Yue, C. Ling, T. Yang, X.B. Chen, Y.L. Chen, H.T. Deng, Q. Wu, J.C. Chen, G.Q. Chen
A seawater-based open and continuous process for polyhydroxyalkanoates production by recombinant Halomonas campaniensis LS21 grown in mixed substrates
Biotechnol. Biofuels, 7 (2014), p. 108
View in Scopus Google Scholar
[49]
M. Keeley, K. Kisslinger, C. Adamson, P.Y. Furlan
Magnetically recoverable and reusable titanium dioxide nanocomposite for water disinfection
J. Mar. Sci. Eng., 9 (2021), p. 943
Crossref View in Scopus Google Scholar
[50]
P.M. Alvarez, J. Jaramillo, F. Lopez-Pinero, P.K. Plucinski
Preparation and characterization of magnetic TiO2 nanoparticles and their utilization for the degradation of emerging pollutants in water
Appl. Catal. B, 100 (2010), pp. 338-345
View PDF View article View in Scopus Google Scholar
[51]
J. Theerthagiri, K. Karuppasamy, S.J. Lee, R. Shwetharani, H.S. Kim, S.K.K. Pasha, M. Ashokkumar, M.Y. Choi
Fundamentals and comprehensive insights on pulsed laser synthesis of advanced materials for diverse photo- and electrocatalytic applications
Light: Sci. Applic., 11 (2022), p. 250
View in Scopus Google Scholar
[52]
S.S. Naik, S.J. Lee, J. Theerthagiri, Y. Yu, M.Y. Choi
Rapid and highly selective electrochemical sensor based on ZnS/Au-decorated f-multi-walled carbon nanotube nanocomposites produced via pulsed laser technique for detection of toxic nitro compounds
J. Hazard. Mater., 418 (2021), Article 126269
View PDF View article View in Scopus Google Scholar
[53]
J. Theerthagiri, S.J. Lee, K. Karuppasamy, S. Arulmani, S. Veeralakshmi, M. Ashokkumar, M.Y. Choi
Application of advanced materials in sonophotocatalytic processes for the remediation of environmental pollutants
J. Hazard. Mater., 412 (2021), Article 125245
View PDF View article View in Scopus Google Scholar
[54]
J. Theerthagiri, J. Park, H.T. Das, N. Rahamathulla, E.S.F. Cardoso, A.P. Murthy, G. Maia, D.V.N. Vo, M.Y. Choi
Electrocatalytic conversion of nitrate waste into ammonia: a review
Environ. Chem. Lett., 20 (2022), pp. 2929-2949
Crossref View in Scopus Google Scholar
[55]
Y. Yu, A. Min, H.J. Jung, J. Theerthagiri, S.J. Lee, K.Y. Kwon, M.Y. Choi
Method development and mechanistic study on direct pulsed laser irradiation process for highly effective dechlorination of persistent organic pollutants
Environ. Pollut., 291 (2021), Article 118158
View PDF View article View in Scopus Google Scholar
[56]
D.T. Elliott, K.W. Tang
Simple staining method for differentiating live and dead marine zooplankton in field samples
Limnol. Oceanogr. Methods, 7 (2009), pp. 585-594
Crossref View in Scopus Google Scholar
[57]
D.J. Reasoner
Heterotrophic plate count methodology in the United States
Int. J. Food Microbiol., 92 (2004), pp. 307-315
View PDF View article View in Scopus Google Scholar
[58]
X.C. Li
Improved pyrogallol autoxidation method: a reliable and cheap superoxide-scavenging assay suitable for all antioxidants
J. Agric. Food Chem., 60 (2012), pp. 6418-6424
Crossref View in Scopus Google Scholar
[59]
Q.L. Shimabuku, T. Ueda-Nakamura, R. Bergamasco, M.R. Fagundes-Klen
Chick-Watson kinetics of virus inactivation with granular activated carbon modified with silver nanoparticles and/or copper oxide
Process. Saf. Environ. Prot., 117 (2018), pp. 33-42
View PDF View article View in Scopus Google Scholar
[60]
Z.J. Ren, L. Zhang, Y. Shi
UV disinfection of Staphylococcus aureus in ballast water: effect of growth phase on the disinfection kinetics and the mechanization at molecular level
Sci. China Technol. Sci., 59 (2016), pp. 330-336
Crossref View in Scopus Google Scholar
[61]
A.H. Geeraerd, V.P. Valdramidis, J.F. Van Impe
GInaFiT, a freeware tool to assess non-log-linear microbial survivor curves
Int. J. Food Microbiol., 110 (2006), p. 297
View PDF View article View in Scopus Google Scholar
[62]
M.T. Laciste, M.D.G. de Luna, N.C. Tolosa, M.C. Lu
Degradation of gaseous formaldehyde via visible light photocatalysis using multi-element doped titania nanoparticles
Chemosphere, 182 (2017), pp. 174-182
View PDF View article View in Scopus Google Scholar
[63]
A.M.B. Nasser, A.K. Muzafar, S.A. Salem, S.C. Ioannis, Y.K. Hak
Influences of silver-doping on the crystal structure, morphology and photocatalytic activity of TiO2 nanofibers
Mater. Sci. Appl., 2 (2011), pp. 1188-1193
Google Scholar
[64]
N. Perkas, A. Lipovsky, G. Amirian, Y. Nitzan, A. Gedanken
Biocidal properties of TiO₂ powder modified with Ag nanoparticles
J. Mater. Chem. B, 1 (2013), pp. 5309-5316
Crossref View in Scopus Google Scholar
[65]
H. Irie, Y. Watanabe, K. Hashimoto
Nitrogen-concentration dependence on photocatalytic activity of TiO2-xNx powders
J. Phys. Chem. B, 107 (2003), pp. 5483-5486
View in Scopus Google Scholar
[66]
J. Ananpattarachai, Y. Boonto, P. Kajitvichyanukul
Visible light photocatalytic antibacterial activity of Ni-doped and N-doped TiO2 on Staphylococcus aureus and Escherichia coli bacteria
Environ. Sci. Pollut. Res., 23 (2016), pp. 4111-4119
Crossref View in Scopus Google Scholar
[67]
D. Shan, Y. Zhao, L.N. Liu, X.Y. Linghu, Y. Shu, W.Q. Liu, M.Y. Di, J.W. Zhang, Z. Chen, H. Liu
Chemical synthesis of silver/titanium dioxide nanoheteroparticles for eradicating pathogenic bacteria and photocatalytically degrading organic dyes in wastewater
Environ. Technol. Innov., 30 (2023), Article 103059
View PDF View article View in Scopus Google Scholar
[68]
R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga
Visible-light photocatalysis in nitrogen-doped titanium oxides
Science, 293 (2001), pp. 269-271
View in Scopus Google Scholar
[69]
C. Li, Z.D. Lu, X.W. Ao, W.J. Sun, X. Huang
Degradation kinetics and removal efficiencies of pharmaceuticals by photocatalytic ceramic membranes using ultraviolet light-emitting diodes
Chem. Eng. J., 417 (2021), Article 130828
View in Scopus Google Scholar
[70]
C.G. Lee, H. Javed, D.N. Zhang, J.H. Kim, P. Westerhoff, Q.L. Li, P.J.J. Alvarez
Porous electrospun fibers embedding TiO2 for adsorption and photocatalytic degradation of water pollutants
Environ. Sci. Technol., 52 (2018), pp. 4285-4293
Crossref View in Scopus Google Scholar
[71]
A. Dziedzic, W. Bochnowski, S. Adamiak, J. Cebulski, I. Virt, M. Kus-Liskiewicz, M. Marzec, P. Potera, A. Zaczek, B. Zdeb
Structure and antibacterial properties of Ag and N doped titanium dioxide coatings containing Ti2.85O4N phase, prepared by magnetron sputtering and annealing
Surf. Coat. Technol., 393 (2020), Article 125844
View PDF View article View in Scopus Google Scholar
[72]
D. Kanakaraju, M.A.A. Jasni, Y.C. Lim
A highly photoresponsive and efficient molybdenum-modified titanium dioxide photocatalyst for the degradation of methyl orange
Int. J. Environ. Sci. Technol., 19 (2022), pp. 5579-5594
Crossref View in Scopus Google Scholar
[73]
C.H. Nguyen, C.C. Fu, R.S. Juang
Degradation of methylene blue and methyl orange by palladium-doped TiO2 photocatalysis for water reuse: efficiency and degradation pathways
J. Clean. Prod., 202 (2018), pp. 413-427
View PDF View article View in Scopus Google Scholar
[74]
A. Heidari, R. Teimuri-Mofrad, K.D. Safa
Photoinduced electron transfer reaction for synthesis of tetrahydroquinoline derivatives with conjugated structure using chlorophyll b-modified magnetic titanium dioxide photocatalyst
Appl. Organomet. Chem., 37 (2023), p. 7259
Google Scholar
[75]
A. Bonnefond, M. Ibarra, E. Gonzalez, M. Barrado, A. Chuvilin, J.M. Asua, J.R. Leiza
Photocatalytic and magnetic titanium dioxide/polystyrene/magnetite composite hybrid polymer particles
Polym. Chem., 54 (2016), pp. 3350-3356
Crossref View in Scopus Google Scholar
[76]
B. Zhang, X.H. Ma, J. Ma, Y.M. Zhou, G.C. Liu, D. Ma, Z.H. Deng, M.M. Luo, Y.J. Xin
Fabrication of rGO and g-C3N4 co-modified TiO2 nanotube arrays photoelectrodes with enhanced photocatalytic performance
J. Colloid Interface Sci., 577 (2020), pp. 75-85
View PDF View article View in Scopus Google Scholar
[77]
Y. Wang, R.T. Wang, N.P. Lin, Y. Wang, X.D. Zhang
Highly efficient microwave-assisted Fenton degradation bisphenol A using iron oxide modified double perovskite intercalated montmorillonite composite nanomaterial as catalyst
J. Colloid Interface Sci., 594 (2021), pp. 446-456
Google Scholar
[78]
S.I. Liochev
Reactive oxygen species and the free radical theory of aging
Free Radic. Biol. Med., 60 (2013), pp. 1-4
View PDF View article View in Scopus Google Scholar

Cited by (2)

Removal of disinfection residual bacteria in UV222, UV222/H2O2 and UV222/peroxymonosulfate systems: what is the safe usage for wastewater reclamation
2025, Water Research
Disinfection residual bacteria (DRB) are widely present in the reclaimed treatment effluents and can regrow during the downstream distribution and storage, posing a threat to the biosafety of reuse applications. Recently, far ultraviolet (UV₂₂₂) have garnered augmented attention due to the highly efficient and energy-intensive oxidation, making them a potential approach for the deep inactivation of DRB. However, there remains a lack of quantitative analyses on how to monitor the disinfection intensity to mitigate the health risks associated with DRB. In this study, we used the UV₂₂₂, UV₂₂₂/H₂O₂ and UV₂₂₂/peroxymonosulfate (PMS) systems to treat model DRB including Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis, and developed a multiparameter model to accurately present the dose-culturability relationship. On this basis, we conducted the simulated disinfection, and detected the viability status and regrowth potential of DRB during the post-disinfection processes. It turned out that UV₂₂₂ alone exhibited the superiority over UV₂₅₄, especially for treating Pseudomonas aeruginosa. UV₂₂₂/H₂O₂ and UV₂₂₂/PMS systems further improved the inactivation rates. The practical UV doses for full-scale reclaimed disinfection (10–200 mJ/cm²) were sufficient for the UV₂₂₂-based systems to inactivate DRB (initial 10⁷ CFU/mL) to the safe level in effluent measured by culture methods. But substantial DRB still persisted in VBNC state, which necessitated higher doses of 200–450 mJ/cm² to further inhibit the regrowth under accidental contamination and prolonged transport/storage culture. Fortunately, H₂O₂ provided residual disinfection for Bacillus subtilis, and PMS performed promising sustained disinfection for all the three DRB. This study provided valuable insights for the expanded application of UV₂₂₂ disinfection and future updates of pathogen standards in reclaimed water treatment.
Structure and Properties of Silver-Platinum-Titanium Dioxide Nanocomposite Coating
2025, Coatings

¹: These authors contributed equally to this work and should be considered co-first authors.

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[1] [1]
L.A. Drake, M.A. Doblin, F.C. Dobbs
Potential microbial bioinvasions via ships' ballast water, sediment, and biofilm
Mar. Pollut. Bull., 55 (2007), pp. 333-341
View PDF View article View in Scopus Google Scholar

[2] [2]
B.Y. Lv, J.H. Shi, T. Li, L.L. Ren, W. Tian, X.L. Lu, Y.C. Han, Y.X. Cui, T. Jiang
Deciphering the characterization, ecological function and assembly processes of bacterial communities in ship ballast water and sediments
Sci. Total Environ., 816 (2022), Article 152721
View PDF View article View in Scopus Google Scholar

[3] [3]
E. Tsolaki, E. Diamadopoulos
Technologies for ballast water treatment: a review
J. Chem. Technol. Biotechnol., 85 (2010), pp. 19-32
Crossref View in Scopus Google Scholar

[4] [4]
R. Sommer, A. Cabaj, G. Hirschmann, T. Haider
Disinfection of drinking water by UV irradiation: basic principles - specific requirements - international implementations
Ozone Sci. Eng., 30 (2008), pp. 43-48
Crossref View in Scopus Google Scholar

[5] [5]
W. Luo, T. Li, Y.D. Li, H.J. Wang, Y. Yuan, S.F. Liu, W.Y. Wang, Q. Wang, J.J. Kang, X.Q. Wang
Watts-level ultraviolet-C LED integrated light sources for efficient surface and air sterilization
J. Semicond., 43 (2022), Article 072301
Crossref View in Scopus Google Scholar

[6] [6]
A.B. Soro, S. Shokri, I. Nicolau-Lapena, D. Ekhlas, C.M. Burgess, P. Whyte, D.J. Bolton, P. Bourke, B.K. Tiwari
Current challenges in the application of the UV-LED technology for food decontamination
Trends Food Sci. Technol., 131 (2022), pp. 264-276
Google Scholar

[7] [7]
V. Baldasso, H. Lubarsky, N. Pichel, A. Turolla, M. Antonelli, M. Hincapie, L. Botero, F. Reygadas, A. Galdos-Balzategui, J.A. Byrne, P. Fernandez-Ibanez
UVC inactivation of MS2-phage in drinking water-modelling and field testing
Water Res., 203 (2021), Article 117496
View PDF View article View in Scopus Google Scholar

[8] [8]
K.O. Maloney, D.P. Morris, C.O. Moses, C.L. Osburn
The role of iron and dissolved organic carbon in the absorption of ultraviolet radiation in humic lake water
Biogeochemistry, 75 (2005), pp. 393-407
Crossref View in Scopus Google Scholar

[9] [9]
K. Song, M. Mohseni, F. Taghipour
Mechanisms investigation on bacterial inactivation through combinations of UV wavelengths
Water Res., 163 (2019), Article 114875
View PDF View article View in Scopus Google Scholar

[10] [10]
R.P. Sinha, D.P. Hader
UV-induced DNA damage and repair: a review
Photochem. Photobiol. Sci., 1 (2022), pp. 225-236
Crossref Google Scholar

[11] [11]
M. Martin-Somer, C. Pablos, C. Adan, R. van Grieken, J. Marugan
A review on LED technology in water photodisinfection
Sci. Total Environ., 885 (2023), Article 163963
View PDF View article View in Scopus Google Scholar

[12] [12]
A.C. Chevremont, J.L. Boudenne, B. Coulomb, A.M. Farnet
Impact of watering with UV-LED-treated wastewater on microbial and physico-chemical parameters of soil
Water Res., 47 (2013), pp. 1971-1982
View PDF View article View in Scopus Google Scholar

[13] [13]
J. Arun, S. Nachiappan, G. Rangarajan, R.P. Alagappan, K.P. Gopinath, E. Lichtfouse
Synthesis and application of titanium dioxide photocatalysis for energy, decontamination and viral disinfection: a review
Environ. Chem. Lett., 21 (2023), pp. 339-362
Crossref View in Scopus Google Scholar

[14] [14]
H.M. Yadav, J.S. Kim, S.H. Pawar
Developments in photocatalytic antibacterial activity of nano TiO2: a review
Korean J. Chem. Eng., 33 (2016), pp. 1989-1998
Crossref View in Scopus Google Scholar

[15] [15]
W.A. Daoud, J.H. Xin, Y.H. Zhang
Surface functionalization of cellulose fibers with titanium dioxide nanoparticles and their combined bactericidal activities
Surf. Sci., 599 (2005), pp. 69-75
View PDF View article View in Scopus Google Scholar

[16] [16]
M. Cho, H. Chung, W. Choi, J. Yoon
Linear correlation between inactivation of E-coli and OH radical concentration in TiO2 photocatalytic disinfection
Water Res., 38 (2004), pp. 1069-1077
View PDF View article View in Scopus Google Scholar

[17] [17]
J. Zhao, V. Krishna, B. Hua, B. Moudgil, B. Koopman
Effect of UVA irradiance on photocatalytic and UVA inactivation of Bacillus cereus spores
J. Photochem. Photobiol. B, 94 (2009), pp. 96-100
View PDF View article Google Scholar

[18] [18]
J. Garcia-Garay, A. Franco-Herrera, F. Machuca-Martinez
Zooplankton sensitivity and phytoplankton regrowth for ballast water treatment with advanced oxidation processes
Environ. Sci. Pollut. Res., 25 (2018), pp. 35008-35014
Crossref View in Scopus Google Scholar

[19] [19]
Z. Lu, K. Zhang, X.L. Liu, Y. Shi
High efficiency inactivation of microalgae in ballast water by a new proposed dual-wave UV-photocatalysis system (UVA/UVC-TiO2)
Environ. Sci. Pollut. Res., 26 (2019), pp. 7785-7792
Crossref View in Scopus Google Scholar

[20] [20]
J. Bogdan, J. Zarzynska, J. Plawinska-Czarnak
Comparison of infectious agents susceptibility to photocatalytic effects of nanosized titanium and zinc oxides: a practical approach
Nanoscale Res. Lett., 10 (2015), p. 309
View in Scopus Google Scholar

[21] [21]
P. Akhter, A. Arshad, A. Saleem, M. Hussain
Recent development in non-metal-doped titanium dioxide photocatalysts for different dyes degradation and the study of their strategic factors: a review
Catalysts, 12 (2022), p. 1331
Crossref View in Scopus Google Scholar

[22] [22]
V. Rehacek, I. Hotovy
Deposition of gold nanoparticles from colloid on TiO2 surface
J. Electr. Eng., 68 (2017), pp. 487-491
Crossref View in Scopus Google Scholar

[23] [23]
J. Singh, B. Satpati, S. Mohapatra
Structural, optical and plasmonic properties of Ag-TiO2 hybrid plasmonic nanostructures with enhanced photocatalytic activity
Plasmonics, 12 (2017), pp. 877-888
Crossref View in Scopus Google Scholar

[24] [24]
S.W. Leong, A. Razmjou, K. Wang, K. Hapgood, X.W. Zhang, H.T. Wang
TiO2 based photocatalytic membranes: a review
J. Membr. Sci., 472 (2014), pp. 167-184
View PDF View article View in Scopus Google Scholar

[25] [25]
X.J. Xiao, J.L. Tu, Z.M. Liu, L. Liu
First principles study of the electronic and optical properties of high-valence transition metal-doped anatase titanium dioxide
Mater. Werkst., 53 (2022), pp. 1551-1560
Crossref View in Scopus Google Scholar

[26] [26]
R.D. Liu, H. Li, L.B. Duan, H. Shen, Y.Y. Zhang, X.R. Zhao
In situ synthesis and enhanced visible light photocatalytic activity of C-TiO2 microspheres/carbon quantum dots
Ceram. Int., 43 (2017), pp. 8648-8654
View PDF View article View in Scopus Google Scholar

[27] [27]
J. Musial, A. Belet, D.T. Mlynarczyk, M. Kryjewski, T. Goslinski, S.D. Lambert, D. Poelman, B.J. Stanisz
Nanocomposites of titanium dioxide and peripherally substituted phthalocyanines for the photocatalytic degradation of sulfamethoxazole
Nanomaterials, 12 (2022), p. 3279
Crossref View in Scopus Google Scholar

[28] [28]
H.M. Yadav, S.V. Otari, V.B. Koli, S.S. Mali, C.K. Hong, S.H. Pawar, S.D. Delekar
Preparation and characterization of copper-doped anatase TiO2 nanoparticles with visible light photocatalytic antibacterial activity
J. Photochem. Photobiol., A, 280 (2014), pp. 32-38
View PDF View article View in Scopus Google Scholar

[29] [29]
H.M. Yadav, S.V. Otari, R.A. Bohara, S.S. Mali, S.H. Pawar, S.D. Delekar
Synthesis and visible light photocatalytic antibacterial activity of nickel-doped TiO2 nanoparticles against Gram-positive and Gram-negative bacteria
J. Photochem. Photobiol., A, 294 (2014), pp. 130-136
View PDF View article View in Scopus Google Scholar

[30] [30]
F. Sayilkan, M. Asilturk, N. Kiraz, E. Burunkaya, E. Arpac, H. Sayilkan
Photocatalytic antibacterial performance of Sn4+-doped TiO2 thin films on glass substrate
J. Hazard. Mater., 162 (2009), pp. 1309-1316
View PDF View article View in Scopus Google Scholar

[31] [31]
H.M.M. Ibrahim
Photocatalytic degradation of methylene blue and inactivation of pathogenic bacteria using silver nanoparticles modified titanium dioxide thin films
World J. Microbiol. Biotechnol., 31 (2015), pp. 1049-1060
Crossref View in Scopus Google Scholar

[32] [32]
L. Caballero, K.A. Whitehead, N.S. Allen, J. Verran
Photocatalytic inactivation of Escherichia coli using doped titanium dioxide under fluorescent irradiation
J. Photochem. Photobiol., A, 276 (2014), pp. 50-57
View PDF View article View in Scopus Google Scholar

[33] [33]
L. Armelao, D. Barreca, G. Bottaro, A. Gasparotto, C. Maccato, C. Maragno, E. Tondello, U.L. Stangar, M. Bergant, D. Mahne
Photocatalytic and antibacterial activity of TiO2 and Au/TiO2 nanosystems
Nanotechnology, 18 (2007), Article 375709
Crossref View in Scopus Google Scholar

[34] [34]
N.C. Raut, T. Mathews, P.K. Ajikumar, R.P. George, S. Dash, A.K. Tyagi
Sunlight active antibacterial nanostructured N-doped TiO2 thin films synthesized by an ultrasonic spray pyrolysis technique
RSC Adv., 2 (2012), pp. 10639-10647
Crossref View in Scopus Google Scholar

[35] [35]
H.U. Lee, S.C. Lee, S.H. Choi, B. Son, S.J. Lee, H.J. Kim, J. Lee
Highly visible-light active nanoporous TiO2 photocatalysts for efficient solar photocatalytic applications
Appl. Catal. B, 129 (2013), pp. 106-113
View PDF View article View in Scopus Google Scholar

[36] [36]
B.F. Xin, Z.Y. Ren, P. Wang, J. Liu, L.Q. Jing, H.G. Fu
Study on the mechanisms of photoinduced carriers separation and recombination for Fe3+-TiO2 photocatalysts
Appl. Surf. Sci., 253 (2007), pp. 4390-4395
View PDF View article View in Scopus Google Scholar

[37] [37]
X.X. Wang, Y.L. Huang, K. Zhang, Y. Shi, Z. Lu, Y.H. Wang
Inactivation effect and mechanisms of combined ultraviolet and metal-doped nano-TiO2 on treating Escherichia coli and Enterococci in ballast water
Environ. Sci. Pollut. Res., 27 (2020), pp. 40286-40295
Crossref View in Scopus Google Scholar

[38] [38]
Y. Liu, J. Huang, X.H. Feng, H. Li
Thermal-sprayed photocatalytic coatings for biocidal applications: a review
J. Therm. Spray Technol., 30 (2021), pp. 1-24
Google Scholar

[39] [39]
X.J. Zhang, W.B. Chen, Z.D. Lin, J.C. Shen
Photocatalytic degradation of a methyl orange wastewater solution using titanium dioxide loaded on bacterial cellulose
Synth. React. Inorg., Met.-Org., Nano-Met. Chem., 41 (2011), pp. 1141-1147
Crossref View in Scopus Google Scholar

[40] [40]
H.B. Yao, M.H. Fan, Y.J. Wang, G.S. Luo, W.Y. Fei
Magnetic titanium dioxide based nanomaterials: synthesis, characteristics, and photocatalytic application in pollutant degradation
J. Mater. Chem. A, 3 (2015), pp. 17511-17524
View in Scopus Google Scholar

[41] [41]
I. Shtein, B. Bar-On, Z.A. Popper
Plant and algal structure: from cell walls to biomechanical function
Physiol. Plant., 164 (2018), pp. 56-66
Crossref View in Scopus Google Scholar

[42] [42]
J. Rodriguez-Chueca, M.P. Ormad, R. Mosteo, J.L. Ovelleiro
Kinetic modeling of Escherichia coli and Enterococcus sp. inactivation in wastewater treatment by photo-Fenton and H2O2/UV-vis processes
Chem. Eng. Sci., 138 (2015), pp. 730-740
View PDF View article View in Scopus Google Scholar

[43] [43]
J.J. Velez-Colmenares, A. Acevedo, E. Nebot
Effect of recirculation and initial concentration of microorganisms on the disinfection kinetics of Escherichia coli
Desalination, 280 (2011), pp. 20-26
View PDF View article View in Scopus Google Scholar

[44] [44]
J. Marugan, R. van Grieken, C. Sordo, C. Cruz
Kinetics of the photocatalytic disinfection of Escherichia coli suspensions
Appl. Catal. B, 82 (2008), pp. 27-36
View PDF View article View in Scopus Google Scholar

[45] [45]
E.N. Sanz, I.S. Davila, J.A.A. Balao, J.M.Q. Alonso
Modelling of reactivation after UV disinfection: effect of UV-C dose on subsequent photoreactivation and dark repair
Water Res., 41 (2007), pp. 3141-3151
Google Scholar

[46] [46]
K. Fitzhenry, E. Clifford, N. Rowan, A.V. del Rio
Bacterial inactivation, photoreactivation and dark repair post flow-through pulsed UV disinfection
J. Water Process Eng., 41 (2021), Article 102070
View PDF View article View in Scopus Google Scholar

[47] [47]
I. Salcedo, J.A. Andrade, J.M. Quiroga, E. Nebot
Photoreactivation and dark repair in UV-treated microorganisms: effect of temperature
Appl. Environ. Microbiol., 73 (2007), pp. 1594-1600
View in Scopus Google Scholar

[48] [48]
H.T. Yue, C. Ling, T. Yang, X.B. Chen, Y.L. Chen, H.T. Deng, Q. Wu, J.C. Chen, G.Q. Chen
A seawater-based open and continuous process for polyhydroxyalkanoates production by recombinant Halomonas campaniensis LS21 grown in mixed substrates
Biotechnol. Biofuels, 7 (2014), p. 108
View in Scopus Google Scholar

[49] [49]
M. Keeley, K. Kisslinger, C. Adamson, P.Y. Furlan
Magnetically recoverable and reusable titanium dioxide nanocomposite for water disinfection
J. Mar. Sci. Eng., 9 (2021), p. 943
Crossref View in Scopus Google Scholar

[50] [50]
P.M. Alvarez, J. Jaramillo, F. Lopez-Pinero, P.K. Plucinski
Preparation and characterization of magnetic TiO2 nanoparticles and their utilization for the degradation of emerging pollutants in water
Appl. Catal. B, 100 (2010), pp. 338-345
View PDF View article View in Scopus Google Scholar

[51] [51]
J. Theerthagiri, K. Karuppasamy, S.J. Lee, R. Shwetharani, H.S. Kim, S.K.K. Pasha, M. Ashokkumar, M.Y. Choi
Fundamentals and comprehensive insights on pulsed laser synthesis of advanced materials for diverse photo- and electrocatalytic applications
Light: Sci. Applic., 11 (2022), p. 250
View in Scopus Google Scholar

[52] [52]
S.S. Naik, S.J. Lee, J. Theerthagiri, Y. Yu, M.Y. Choi
Rapid and highly selective electrochemical sensor based on ZnS/Au-decorated f-multi-walled carbon nanotube nanocomposites produced via pulsed laser technique for detection of toxic nitro compounds
J. Hazard. Mater., 418 (2021), Article 126269
View PDF View article View in Scopus Google Scholar

[53] [53]
J. Theerthagiri, S.J. Lee, K. Karuppasamy, S. Arulmani, S. Veeralakshmi, M. Ashokkumar, M.Y. Choi
Application of advanced materials in sonophotocatalytic processes for the remediation of environmental pollutants
J. Hazard. Mater., 412 (2021), Article 125245
View PDF View article View in Scopus Google Scholar

[54] [54]
J. Theerthagiri, J. Park, H.T. Das, N. Rahamathulla, E.S.F. Cardoso, A.P. Murthy, G. Maia, D.V.N. Vo, M.Y. Choi
Electrocatalytic conversion of nitrate waste into ammonia: a review
Environ. Chem. Lett., 20 (2022), pp. 2929-2949
Crossref View in Scopus Google Scholar

[55] [55]
Y. Yu, A. Min, H.J. Jung, J. Theerthagiri, S.J. Lee, K.Y. Kwon, M.Y. Choi
Method development and mechanistic study on direct pulsed laser irradiation process for highly effective dechlorination of persistent organic pollutants
Environ. Pollut., 291 (2021), Article 118158
View PDF View article View in Scopus Google Scholar

[56] [56]
D.T. Elliott, K.W. Tang
Simple staining method for differentiating live and dead marine zooplankton in field samples
Limnol. Oceanogr. Methods, 7 (2009), pp. 585-594
Crossref View in Scopus Google Scholar

[57] [57]
D.J. Reasoner
Heterotrophic plate count methodology in the United States
Int. J. Food Microbiol., 92 (2004), pp. 307-315
View PDF View article View in Scopus Google Scholar

[58] [58]
X.C. Li
Improved pyrogallol autoxidation method: a reliable and cheap superoxide-scavenging assay suitable for all antioxidants
J. Agric. Food Chem., 60 (2012), pp. 6418-6424
Crossref View in Scopus Google Scholar

[59] [59]
Q.L. Shimabuku, T. Ueda-Nakamura, R. Bergamasco, M.R. Fagundes-Klen
Chick-Watson kinetics of virus inactivation with granular activated carbon modified with silver nanoparticles and/or copper oxide
Process. Saf. Environ. Prot., 117 (2018), pp. 33-42
View PDF View article View in Scopus Google Scholar

[60] [60]
Z.J. Ren, L. Zhang, Y. Shi
UV disinfection of Staphylococcus aureus in ballast water: effect of growth phase on the disinfection kinetics and the mechanization at molecular level
Sci. China Technol. Sci., 59 (2016), pp. 330-336
Crossref View in Scopus Google Scholar

[61] [61]
A.H. Geeraerd, V.P. Valdramidis, J.F. Van Impe
GInaFiT, a freeware tool to assess non-log-linear microbial survivor curves
Int. J. Food Microbiol., 110 (2006), p. 297
View PDF View article View in Scopus Google Scholar

[62] [62]
M.T. Laciste, M.D.G. de Luna, N.C. Tolosa, M.C. Lu
Degradation of gaseous formaldehyde via visible light photocatalysis using multi-element doped titania nanoparticles
Chemosphere, 182 (2017), pp. 174-182
View PDF View article View in Scopus Google Scholar

[63] [63]
A.M.B. Nasser, A.K. Muzafar, S.A. Salem, S.C. Ioannis, Y.K. Hak
Influences of silver-doping on the crystal structure, morphology and photocatalytic activity of TiO2 nanofibers
Mater. Sci. Appl., 2 (2011), pp. 1188-1193
Google Scholar

[64] [64]
N. Perkas, A. Lipovsky, G. Amirian, Y. Nitzan, A. Gedanken
Biocidal properties of TiO₂ powder modified with Ag nanoparticles
J. Mater. Chem. B, 1 (2013), pp. 5309-5316
Crossref View in Scopus Google Scholar

[65] [65]
H. Irie, Y. Watanabe, K. Hashimoto
Nitrogen-concentration dependence on photocatalytic activity of TiO2-xNx powders
J. Phys. Chem. B, 107 (2003), pp. 5483-5486
View in Scopus Google Scholar

[66] [66]
J. Ananpattarachai, Y. Boonto, P. Kajitvichyanukul
Visible light photocatalytic antibacterial activity of Ni-doped and N-doped TiO2 on Staphylococcus aureus and Escherichia coli bacteria
Environ. Sci. Pollut. Res., 23 (2016), pp. 4111-4119
Crossref View in Scopus Google Scholar

[67] [67]
D. Shan, Y. Zhao, L.N. Liu, X.Y. Linghu, Y. Shu, W.Q. Liu, M.Y. Di, J.W. Zhang, Z. Chen, H. Liu
Chemical synthesis of silver/titanium dioxide nanoheteroparticles for eradicating pathogenic bacteria and photocatalytically degrading organic dyes in wastewater
Environ. Technol. Innov., 30 (2023), Article 103059
View PDF View article View in Scopus Google Scholar

[68] [68]
R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga
Visible-light photocatalysis in nitrogen-doped titanium oxides
Science, 293 (2001), pp. 269-271
View in Scopus Google Scholar

[69] [69]
C. Li, Z.D. Lu, X.W. Ao, W.J. Sun, X. Huang
Degradation kinetics and removal efficiencies of pharmaceuticals by photocatalytic ceramic membranes using ultraviolet light-emitting diodes
Chem. Eng. J., 417 (2021), Article 130828
View in Scopus Google Scholar

[70] [70]
C.G. Lee, H. Javed, D.N. Zhang, J.H. Kim, P. Westerhoff, Q.L. Li, P.J.J. Alvarez
Porous electrospun fibers embedding TiO2 for adsorption and photocatalytic degradation of water pollutants
Environ. Sci. Technol., 52 (2018), pp. 4285-4293
Crossref View in Scopus Google Scholar

[71] [71]
A. Dziedzic, W. Bochnowski, S. Adamiak, J. Cebulski, I. Virt, M. Kus-Liskiewicz, M. Marzec, P. Potera, A. Zaczek, B. Zdeb
Structure and antibacterial properties of Ag and N doped titanium dioxide coatings containing Ti2.85O4N phase, prepared by magnetron sputtering and annealing
Surf. Coat. Technol., 393 (2020), Article 125844
View PDF View article View in Scopus Google Scholar

[72] [72]
D. Kanakaraju, M.A.A. Jasni, Y.C. Lim
A highly photoresponsive and efficient molybdenum-modified titanium dioxide photocatalyst for the degradation of methyl orange
Int. J. Environ. Sci. Technol., 19 (2022), pp. 5579-5594
Crossref View in Scopus Google Scholar

[73] [73]
C.H. Nguyen, C.C. Fu, R.S. Juang
Degradation of methylene blue and methyl orange by palladium-doped TiO2 photocatalysis for water reuse: efficiency and degradation pathways
J. Clean. Prod., 202 (2018), pp. 413-427
View PDF View article View in Scopus Google Scholar

[74] [74]
A. Heidari, R. Teimuri-Mofrad, K.D. Safa
Photoinduced electron transfer reaction for synthesis of tetrahydroquinoline derivatives with conjugated structure using chlorophyll b-modified magnetic titanium dioxide photocatalyst
Appl. Organomet. Chem., 37 (2023), p. 7259
Google Scholar

[75] [75]
A. Bonnefond, M. Ibarra, E. Gonzalez, M. Barrado, A. Chuvilin, J.M. Asua, J.R. Leiza
Photocatalytic and magnetic titanium dioxide/polystyrene/magnetite composite hybrid polymer particles
Polym. Chem., 54 (2016), pp. 3350-3356
Crossref View in Scopus Google Scholar

[76] [76]
B. Zhang, X.H. Ma, J. Ma, Y.M. Zhou, G.C. Liu, D. Ma, Z.H. Deng, M.M. Luo, Y.J. Xin
Fabrication of rGO and g-C3N4 co-modified TiO2 nanotube arrays photoelectrodes with enhanced photocatalytic performance
J. Colloid Interface Sci., 577 (2020), pp. 75-85
View PDF View article View in Scopus Google Scholar

[77] [77]
Y. Wang, R.T. Wang, N.P. Lin, Y. Wang, X.D. Zhang
Highly efficient microwave-assisted Fenton degradation bisphenol A using iron oxide modified double perovskite intercalated montmorillonite composite nanomaterial as catalyst
J. Colloid Interface Sci., 594 (2021), pp. 446-456
Google Scholar

[78] [78]
S.I. Liochev
Reactive oxygen species and the free radical theory of aging
Free Radic. Biol. Med., 60 (2013), pp. 1-4
View PDF View article View in Scopus Google Scholar

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