阴极还原脱氯-阳极电化学氧化耦合催化降解酚类有机污染物效能与机理

The electrocatalytic reductive dechlorination is an environmental friendly pretreatment method for achieving the chlorinated organic pollutants being degraded nontoxically and harmlessly. While, the problems of low dechlorination efficiency, unused anode and energy waste, are existed in the present research. In this project, the coupling catalytic degradation of cathodic reductive dechlorination and anodic electrochemical oxidation is adopted to achieve dechlorination of chlorophenols at cathode and oxidative degradation of refractory non-chlorinated phenols at anode simultaneously. In this way, the effective pollutant degradation and the efficient energy utilization can be achieved at the same time. To solve the problems existed in the present research, such as low dechlorination efficiency at cathode, low oxidation efficiency at anode and low mass transfer efficiency in the electrochemical process, graphene modified palladium-loaded cathode with high electrocatalytic reductive dechlorination activity and high stability will be prepared using meshed titanium as substrate, and rare earth elements doped SnO2-Sb anode (e.g. Sc) with high electrocatalytic oxidation activity will be prepared using micro-porous titanium plate as substrate. The coupling conditions of cathodic and anodic reactions will be optimized. The interaction of graphene, polypyrrole and surfactant with palladium particles, and their roles in the electrocatalytic activity, will be studied. The dechlorination pathway and mechanism of polychlorinated phenols, as well as the electrocatalytic oxidation kinetics and mechanism of non-chlorinated phenols, will be investigated. The research will provide the theoretical basis for the nontoxic and harmless degradation of chlorinated organic pollutants with high efficiency and low energy consumption.

电催化还原脱氯是实现氯代有机污染物无毒无害化降解的环境友好的预处理方法，目前研究中存在着脱氯效率低、阳极未利用、能源浪费等问题。项目采用阴极还原脱氯-阳极电化学氧化耦合催化降解的方法，在实现氯酚类污染物阴极还原脱氯的同时，将阳极用于难降解的不含氯的酚类污染物的氧化降解，以同时实现污染物高效降解和能源高效利用。为了解决目前研究中存在的阴极脱氯效率低、阳极氧化效率低、电化学过程传质效率低等问题，拟研究制备以多孔钛网为基体材料的电催化还原脱氯活性高、性能稳定的石墨烯修饰的载Pd催化阴极，以微孔钛板为基体材料的、电氧化活性高的Sc等掺杂的SnO2-Sb催化阳极，优化调控阴阳极耦合条件，分析石墨烯、聚吡咯、表面活性剂与金属催化剂钯颗粒之间的相互作用及其与电催化活性的关系，探讨多氯苯酚的脱氯路径与机理、电催化氧化的反应动力学与氧化机制，为实现低耗、高效的氯酚类污染物的无毒无害化降解提供理论依据。

电催化还原脱氯是实现氯代有机污染物无毒无害化降解的环境友好方法，但该方法目前仍存在脱氯效率低、阳极未利用和能源浪费等问题。项目采用阴极还原脱氯-阳极电化学氧化耦合催化降解的方法，在实现氯酚类污染物阴极还原脱氯的同时，将阳极用于脱氯产物苯酚的氧化降解，同时实现污染物的高效降解和能源的高效利用。.制备了电催化活性高、性能稳定的石墨烯修饰载Pd 催化阴极，包括Pd/GrEPD/SDBS-PPy/Ti电极、PdPP/Gr/SDBS-PPy/Ti电极和Pd/Gr-Nafion/Ti电极，石墨烯的加入可使Pd颗粒均匀分散在电极表面，提高了电极催化性能。研究了氯酚类污染物的电催化还原脱氯过程，实现了2,3,6-TCP、2,4,6-TCP和2,3,5-TCP的高效脱氯。在脱氯电流为5 mA，阴极液初始pH为1.0，且不加缓冲溶液的条件下，PdPP/Gr/SDBS-PPy/Ti电极上在70min内可实现三种TCPs的完全去除，脱氯过程不受水溶液中常见阴阳离子的干扰。.制备了稀土元素掺杂的Ti/SnO2-Sb阳极，包括单掺SnO2-Sb电极、二元金属掺杂电极和三元复合掺杂电极，在阳极氧化体系中实现了脱氯产物苯酚的完全转化。以制备的Ti/SnO2-Sb-Ni-Nd为阳极，在电流密度为10 mA cm-2、阳极液初始pH 5.6条件下，电解2h可实现苯酚的完全转化。.构建阴阳极耦合降解体系，在隔膜反应器内，石墨烯修饰载Pd 催化阴极对氯酚进行还原脱氯，稀土元素掺杂的Ti/SnO2-Sb阳极对苯酚进行氧化，阴阳极耦合降解酚类污染物。考察了阳极电流密度、电解液浓度、pH值等因素对阴阳极耦合效果的影响。阴极2,4,6-TCP 150mg/L、阴极液体积140mL、阴极液pH 2.3、阳极苯酚50mg/L、阳极液体积80mL、阳极液pH 5.5、阳极与单个阴极面积比1:5、阴极液与阳极液体积比1.75: 1时，90min可实现阴极2,4,6-TCP和阳极苯酚的完全转化。.项目构建的阴阳极耦合体系实现了阴极氯酚与阳极苯酚的同步高效耦合降解，为水中酚类污染物的高效去除及节能降耗提供了切实可行的技术及相关的理论依据。.