环境污染物低压电化学转化的系统强化及机制解析

Electrochemical oxidation is an important strategy for water treatment. Pollutants conversion at low bias before oxygen evolution possesses the main advantages of high current efficiency and low energy consumption. However, at the same time, this simple electrochemical strategy still has several intrinsic bottlenecks, such as low activity, slow kinetics, weak stability and limited capacity for practical applications. In this proposal, we would like to in situ construct the inorganic and organic Fenton catalytic systems in the low-bias electrochemical conversion system aiding by the in-situ generated anodic polymers with abundant quinone function groups and excellent charge-transfer reactivity, and to construct the photochemical catalytic system in the low-bias electrochemical conversion system aiding by the functional transition metal oxides as anodic materials with both excellent anodic and photochemical activities. By these ways, the in-situ generated anodic polymers with highly stable and resistant capacities could be effectively removed from electrode surface in the oxidative mode, then the electrode anti-fouling and reactive sites regeneration could be efficiently realized in the refined low-bias electrochemical conversion systems, which could strongly promote the effective, stable and cost-effective removal of organic pollutants from water and wastewater. Meanwhile, we aimed to systematically investigate the removal efficiency, catalytic mechanism and technical properties of the refined low-bias electrochemical conversion systems during typical refractory pollutants degradation for a long-term operation. These findings might provide a new chance to refine the electrochemical water treatment, as well as its potentials for practical applications.

电化学氧化是一种重要的水污染控制手段。在析氧副反应发生前的污染物低压转化体系具有电流效率高和电能消耗低的技术优势，但同时存在催化活性弱、反应动力学慢、工艺稳定性差和处理能力小等工艺缺陷，极大制约其水处理实际应用潜能。本项目拟在污染物低压电化学转化体系内部分别借助阳极聚合物的优异电子穿梭能力和部分阳极材料的光、电双重催化特性来原位构建类Fenton氧化和光催化氧化等耦合反应系统，利用氧化能力突出的各种活性自由基选择性将被沉积于电极表面、物化性质稳定和难以被有效转化的电化学聚合物进一步降解，达到消除电极污染、再生吸附和催化活性位点和提高电化学工艺效能，最终实现污染物低压转化体系低耗、高效和稳定运行。通过深入研究和探讨低压电化学强化转化工艺在典型持久性有机污染物深度去除过程中的去除效果、作用机制和技术特性，为电化学水处理技术提供有效的强化策略和提升应用潜能。

项目执行期内，发展和揭示多种“低压电化学强化转化体系”的构建方法、催化机制和反应特性，探究多种环境友好型催化剂的优化制备参数和获取方法，试制并系统测试2套高效、稳定的水处理样本装置。研究典型纳米材料作为环境光催化剂、电催化剂和类芬顿催化剂在污染物吸附、氧化剂活化和多相催化反应过程中活性表界面的物化结构、配位环境和电荷分布的微观变化及转移规律，提高功能材料和组装结构针对典型有机微污染物的富集、降解效能，发展基于纳米材料与催化技术高效耦合的水质净化新体系和新技术，实现典型有机微污染物的高效转化和彻底去除。面向低浓度持久性有机污染物的高效清除，强化电化学耦合体系将目标污染物的界面吸附、催化降解和活性再生进行耦合集成。. 主要发展以低压电化学转化过程中产生的活性阳极聚合物为关键电子传递媒介的原位有机类Fenton体系、极性晶面调控TiO2阳极表面缺陷位点介导的光辅助低压电催化体系（低于析氧电位）、工业贵金属Pd中毒副产物Pd4S介导的多相类Fenton催化体系、极性晶面调控TiO2阳极介导的高压电催化体系（高于析氧电位）、环境和工业制品中有机微污染物的电催化检测和光化学再生体系、利用有机砷类污染物原位促进酚类污染物高效光催化降解策略、缺陷型TiO2活化过硫酸盐的类Fenton催化体系和采用缺陷工程手段调控WO3电子特性提高催化性能等。系统揭示强化耦合体系在不同反应条件下的催化效能、反应机制和能耗特性，深入分析饮用水/地表水源水中典型低浓度酚类污染物、农药、有机砷和腐殖质的富集、降解和矿化规律以及反应构效关系和电子交互效应，有效建立环境和工业制品中典型持久性有机微污染物的高效、稳定分析检测方法，初步阐明纳米材料的结构、性能和制备之间的内在联系。在此基础上，设计并运行2套“低压电化学转化强化系统”的水处理耦合反应器并完成系统优化，为后续工业应用系统设计研发提供理论依据和技术支撑。