光电耦合催化降解再生水中类固醇类雌激素及协同灭菌机制

The complex components of reclaimed water with a variety of trace organic pollutants such as the typical steroid estrogens (SEs) and pathogen microorganisms impede the safe utilization of reclaimed water. Our project selects SEs and pathogen microorganisms as targeted contaminant. The optimal Ag-TiO2NTAs/SnO2-Sb2O5 photocatalysis anode and C-PTFE/Ag-TiO2 photocatalysis cathode are applied in the photoelectric coupling catalytic system. In this system, anode electric catalyst active sites and load is improved; the cathode accumulation of H2O2 is solved by photochemical process; photo-production electronic-hole pair is separated effectively by electrochemical process; and it realize the coupling of photocatalytic process the electric catalytic process. Interactions between the photoelectric coupling systems and contributions of each part on SEs degradation and sterilization mechanism are investigated. The mechanisms of SEs degradation and sterilization in the presence of dissolved effluent organic matter (EfOM) are also explored in the coupling system. The effect of photoelectric coupling catalytic reactor was evaluated comprehensively. Moreover, eco-toxicity and estrogenic activity for the SEs degradation products are also evaluated. The potential ecological risks of reclaimed water from waste water treated by coupling system are also evaluated. This study provides a theoretical basis for the development of photoelectric coupling catalytic technology.

再生水中存在的多种痕量有机污染物如类固醇类雌激素（SEs）、病原体微生物等成为再生水安全利用的瓶颈。本项目拟以SEs和病原体微生物为目标污染物，以优化制备的Ag-TiO2NTAs/SnO2-Sb2O5作光催化阳极、C-PTFE/Ag-TiO2作光催化阴极构建稳定的光电耦合催化体系，提高阳极板电催化剂的活性位点和负载量，光化学过程解决阴极H2O2的堆积，电化学过程有效分离光催化中产生的光生电子-空穴对，实现电催化过程与光催化过程的有机耦合；系统研究光电耦合体系之间的相互作用及对SEs降解和协同灭菌的机理；阐明污水处理厂出水溶解性有机质介导光电耦合催化体系去除SEs和协同灭菌的机制；综合评价光电耦合催化反应器处理效果，探讨光电耦合体系对SEs生态毒性和雌激素活性的改变，评估经处理的含SEs污水作为再生水时的潜在生态风险，为光电耦合催化技术研发提供理论基础。

通常来说，再生水中所含的微量有机污染物、耐药细菌和耐药基因对生态系统和人类健康的危害较大，导致再生水的回用受限。本项目成功构建了一种高效的光电耦合催化体系（以TNTAs-Ag/SnO2-Sb和BiFeO3-TNTAs为阳极、C-PTFE和Ti-Pd/SnO2-Sb为阴极）用于再生水处理，主要能针对性地去除其中残留的微量有机污染物、耐药细菌和耐药基因。通过改变光电催化体系初始pH值、电流密度、光照强度等条件以及多次重复试验考察该体系中阳极的稳定性和重复利用率，重点考察了该体系对雌激素和抗生素的降解能力以及对大肠杆菌的灭活能力。同时，进一步明确了光电耦合体系灭活抗性菌、去除抗性基因及降解抗生素是由于该体系产生的高浓度活性物质所导致的。阐明了光电耦合体系对抗性菌内DNA的破坏程度以及对抗性基因的去除。此外，采用MFC-7细胞作为体外细胞模型评估降解产物的雌激素活性，结果表明经该体系处理后的再生水其潜在生态风险较低。通过LC-MS/MS对该体系中雌激素降解的中间产物进行鉴定并推测其结构，在此基础上提出了雌激素可能的降解途径。最后，根据出水溶解性有机质介导的污染物降解机制及其最佳的作用条件，构建了一种高效、低耗能的光电催化体系降解再生水中痕量有机污染物和抗性菌。本课题的研究为保证再生水的安全回用提供了有效的技术手段。