膜法水处理技术由于操作简单、分离效率高已被逐步应用于废水和饮用水的深度处理。然而，在水处理过程中发生的膜生物污染会显著降低膜透水率、缩短膜寿命、增加处理成本，这是制约膜技术推广应用的一个关键问题。近几年来出现的新型电耦合膜过滤（ECMF）技术具有能耗低、无需对原水进行化学预处理等优点，但是其在膜生物污染控制方面的应用前景尚待深入研究。

本论文采用不同碳纳米管（CNT）负载量以及分散剂质量比，制备得到具有不同 H₂O₂产能、膜透水率以及电化学性能的CNT复合膜。将该复合膜用作阴极，以铜绿假单胞菌（P. aeruginosa）为模式微生物，分别考察了不同电压下，阴极膜表面附着细菌和生物膜的溶解效果，以及由此导致的膜污染减缓效果与机制。在此基础上，从自来水末梢水中筛选出多种类型氯抗性菌株，通过革兰氏染色、16S rRNA鉴定、发育树构建等方法获取了耐氯菌的种属信息。继而探讨了耐氯菌的微生物特性与其耐氯水平、膜污染潜势以及抗阴极膜溶解的关联机制，确定了典型耐氯菌生物膜个体化差异性对ECMF溶解效能的影响。最后，结合死端膜过滤系统的运行特点，探讨了ECMF与水力反冲洗结合对膜生物污染的控制效果。

比较不同CNT复合膜发现，CNT负载量为1 mg cm^-2、分散剂与CNT质量比 = 1:1的复合膜具有纤维交错、分布均匀平整的CNT层，膜透水率为7.83 L m^-2 h^-1 kPa^-1，出水H₂O₂浓度在外加3.0 V电压、溶液NaCl浓度为0.8 g L^-1时，达到0.28 mM，最适于ECMF处理需要。

利用电耦合膜过滤溶解膜表面附着的铜绿假单胞菌及其生物膜时发现，外加3.0 V电压，过滤3 h，可有效去除膜表面99.23%的附着细菌，而不加电比外加0.26 mM或0.53 mM H₂O₂分别造成2.37%和33.31%的细菌溶解。持续过滤至21 h，可使生物膜中活细菌比例降低93.92%，生物体积量降低98.6%，污染膜的相对跨膜压差从4.23降低到2.06。生物电化学效应的多效协作机制是ECMF体系控制膜生物污的主要作用机制。

进一步将死端ECMF应用于耐氯菌膜污染控制，发现无过滤条件下，低压电场结合20 mM H₂O₂处理45 min，浮游的高耐氯菌的对数存活率为4.86 log，灭菌效果优于单纯的H₂O₂处理（6.53 log）。对ECMF系统施加3.0 V电压，过滤3h，可以基本溶解膜表面低氯抗性菌株（抗氯指数 < 6），或破坏高氯抗性菌株（抗氯指数 ≥ 6）。过滤48 h，可溶解具有高耐氯性、高耐H₂O₂特性菌株FB3的生物膜，恢复88.71%的跨膜压差，并去除71.91% 的胞外聚合物（EPS）和50.90%的生物体积量；相同时间可溶解具有高EPS分泌能力、低耐氯性的菌株FG12生物膜，恢复93.25%的跨膜压差，去除91.71%的EPS和61.12%的生物体积量。此外，研究发现胞外聚合物（EPS）作为细菌细胞的保护屏障，会被电耦合膜过滤优先降解，该过程对跨膜压差恢复的贡献大于膜表面生物量的降低。

最后，在膜法水处理相关操作条件下进行电耦合膜过滤，发现相比于不施加电压的对照组，死端ECMF体系能更有效地抑制细菌增殖以及EPS分泌，推迟跨膜压差剧增的拐点时间，有效延缓膜生物污染进程。与错流ECMF不同， 死端ECMF可结合较高频率水力反冲洗，在1440 min过滤时间内，使膜不可逆污染占比维持在10%以下，系统跨膜压差无明显变化，出水H₂O₂ 浓度和系统电流密度分别稳定在 0.23 ± 0.02 mM 和 0.61 ± 0.04 mA左右。膜表征结果进一步揭示，水力反冲洗能及时去除膜表面可逆污垢层，维持CNT复合膜的电化学性能，从而实现基于死端ECMF系统的可持续膜生物污染控制。

本研究为膜法水处理系统中耐氯菌膜污染控制提供了新的技术解决方案，对于深度水处理和回用技术的创新也具有重要的理论指导意义。

Membrane-based water treatment technology has been gradually applied to advanced water and wastewater treatment due to its facile operation and high separation efficiency. However, the occurrence of membrane biofouling during the water treatment process significantly reduces membrane permeability, shortens membrane life, and increases treatment costs. Thus, it is a key issue that restricts broader application of membrane technology. In recent years, the newly developed electrocoupled membrane filtration (ECMF) technology has emerged with the advantages of low energy consumption and no need for chemical pretreatment of the raw water. However, its prospects in membrane biofouling control have yet been studied in depth.

In this work, CNT-composite membranes with different H₂O₂ production capacity, membrane water permeability and electrochemical properties were prepared by using different carbon nanotube (CNT) loadings and CNT-to-dispersant mass ratios. The composite membrane was used as a cathode, and Pseudomonas aeruginosa was used as a model microorganism to investigate the electrolysis of bacteria and biofilm attached onto the cathode surface under different applied voltages. The resulting efficacy and mechanisms of membrane biofouling reduction were also determined. Accordingly, several types of chlorine-resistant strains were screened from the laboratory tap water, and the genus information of chlorine-resistant bacteria was obtained by Gram staining, 16S rRNA identification, and developmental tree construction. Subsequently, the relationships between the microbiological characteristics of these bacteria and their chlorine-resistance levels, membrane fouling potentials, and resistance levels to cathodic membrane electrolysis, were studied. Also, the effects exerted by the variable characteristics of chlorine-resistant bacterial biofilms on the electrolytic efficacy of ECMF were determined. Finally, the combined effect of ECMF with hydraulic backwashing on membrane biofouling control was investigated based on the operational characteristics of dead-end membrane filtration systems.

Comparing different CNT-composite membranes, the composite membrane with CNT loading of 1 mg cm^-2 and dispersant to CNT mass ratio = 1:1 had a more uniformly distributed, interlaced CNT layer, and a clean water permeability of 7.83 L m^-2 h^-1 kPa^-1. The H₂O₂ concentration in the filter permeate reached 0.28 mM with an applied voltage of 3.0 V and a NaCl concentration of 0.8 g L^-1. This membrane was most suitable for ECMF treatment.

When ECMF was used to electrolyze P. aeruginosa and its biofilm attached on the membrane surface, the lysis of P. aeruginosa cells with an applied voltage of 3.0 V was nearly completed within 3 h. Comparatively, the addition of 0.26 mM and 0.53 mM H₂O₂ caused 2.37% and 33.31% lysis of the bacterial cells, respectively. Continuous filtration for 21 h, ECMF inactivated 93.92% of the live bacteria in the biofilm and removed 98.6% of the biovolume, which reduced the relative transmembrane pressure (TMP) of the fouled membrane from 4.23 to 2.06. The synergism of bioelectrochemical effects was found to be the main mechanism for the ECMF system to control biofouling.

The dead-end ECMF system was further applied to control membrane fouling caused by chlorine-resistant bacteria. For a planktonic bacteria with strong chlorine resistance, the logarithmic survival rate was 4.86 after 45 min of treatment with low-voltage electric field and 20 mM of spiked H₂O₂, which was better than that with H₂O₂ alone (6.53 log). For ECMF with an applied voltage of 3.0 V, low chlorine-resistant bacterial strains (chlorine resistance index < 6) attached on the membrane surface was almost completely eliminated, whereas the strains with high chlorine resistance (chlorine resistance index ≥ 6) were destroyed in 3 h. After 48 h, the ECMF eliminated the biofilm formed by strain FB3 with high chlorine and H₂O₂ resistance, recovered in 88.71% of the TMP, and remove 71.91% of the extracellular polymeric substances (EPS) and 50.90% of the biovolume. Under the same condition, ECMF also eradicated the biofilm formed by strain FG12 that had high EPS secretion capacity and low chlorine resistance, recovered 93.25% of the TMP, and removed 91.71% of EPS and 61.12% of biovolume. In addition, EPS, which acted as protective barriers for the bacterial cells, were preferentially degraded by ECMF, which contributed more to the recovery of the transmembrane pressure than the biomass.

Finally, the dead-end ECMF system was operated under conditions relevant to practical membrane water treatment. Compared with the control group without the applied voltage, ECMF more efficiently inhibited bacterial proliferation and EPS secretion and postponed the turning point of the TMP for dramatic increase. This effectively slowed down the membrane biofouling process. Unlike cross-flow ECMF, the dead-end ECMF system can be combined with high-frequency hydraulic backwashing to keep the irreversible membrane fouling level to be below 10% within 1440 min of filtration. Indeed, the TMP of the system did not change significantly, and the permeate H₂O₂ concentration and the system current density were also stabilized at 0.23 ± 0.02 mM and 0.61 ± 0.04 mA, respectively. The membrane characterization results further revealed that timely removal of the reversible fouling layer by hydraulic backwash was capable of maintain the electrochemical performance of CNT composite membranes, thus sustainably controlling membrane biofouling in the ECMF system.

This study provided a novel technical solution to the control of chlorine-resistant bacteria fouling in membrane-based water treatment systems, and had important theoretical implications for the innovation of advanced water treatment and reuse technologies.