MFC产电驱动-光电催化/电Fenton“双极双效”耦合氧化体系构建及其深度处理煤化工废水机理研究

Coal chemical wastewater must be advanced treated to meet the requirements of reuse due to its serious environmental pollution. Efficient processing technologies, e.g. photoelectro catalytic and electro Fenton oxidation, require a lot of power consumption. In this project, the MFC driving photoelectro catalytic/electro Fenton bipolar oxidation system is constructed based on the power generation characteristics of MFC. Nano-TiO2/Ti photoelectrocatalytic anode and Fe@Fe2O3/CF electro Fenton cathode are prepared and optimized by orthogonal test. By monitoring the change of the concentration of •OH in the photocatalytic anode chamber and the concentration of H2O2 in the electric Fenton cathode chamber, the catalytic mechanism of Nano-TiO2/Ti, the mechanisms of photogenerated electrons and hole in •OH formation as well as O2 electronic reduction mechanism on Fe@Fe2O3/CF are analysed; The kinetic models of •OH and H2O2 generation are established; Real coal chemical wastewater was used as MFC anode fuel，and the optimal control parameters of combined oxidation system in advanced treatment of coal chemical wastewater are determined by the analysis of pollutant removal efficiency; The mechanisms and kinetics of pollutant degradation are determined as well. This project provides theoretical basis and technical support for the advanced treatment of coal chemical wastewater, which has important scientific research significance and engineering application value.

煤化工废水污染严重，必须经过深度处理以满足回用要求。光电催化与电Fenton等高效废水处理工艺均需消耗大量电能。本项目将MFC产电特性同光电催化及电Fenton技术相耦合，构建MFC原位产电驱动的光电催化/电Fenton“双极双效”氧化体系。通过多因素正交试验制备纳米TiO2/Ti光电催化阳极与Fe@Fe2O3/CF电Fenton阴极并对其表征分析；通过研究光电催化阳极室•OH浓度与电Fenton阴极室H2O2浓度变化规律，揭示纳米TiO2/Ti催化机理、光生电子与空穴在•OH生成中的作用机制，以及O2在Fe@Fe2O3/CF电Fenton阴极表面的电子还原机制；建立•OH与H2O2生成动力学模型。以实际废水为MFC阳极燃料，确定耦合氧化体系协同深度处理煤化工废水的最优控制参数，揭示典型污染物在“双极”各室内的降解机理，并建立其降解动力学模型。本项目具有重要的科学研究意义和工程应用价值。

本项目将光催化/微生物燃料电池和电芬顿氧化技术相结合，构建光催化-电芬顿双池氧化体系和微生物燃料电池-电芬顿耦合体系，对苯酚废水，养猪场废水和罗丹明B染料废水进行处理，在减少成本投入的同时以提高废水降解效能。通过超声浸泡法优化制备Fe@Fe2O3/CF电芬顿阴极，阳极氧化法优化制备TiO2/Ti光催化阳极，构建构建光催化-电芬顿双池氧化体系。采取溶液超声浸泡法制备Fe@Fe2O3/ACF作为复合阴极，以ACF作为阳极，进行接种、驯化培养产电微生物，构建微生物燃料电池-电芬顿耦合体系处理养猪场废水和罗丹明B废水。通过单因素实验探究氧化体系受各种因素的影响情况，得到最优运行工艺参数如下：阴极曝气速率为0.4 L/min，施加电流密度为10.0 mA/cm2，阴极池pH为3，阳极池pH为7，电解质Na2SO4浓度为0.05 mol/L，阳极紫外光光照强度为500 mW/cm2。在此条件下，经过180 min反应时间后，阴极池中总酚和COD的去除率分别为98.7%和85.6%，阳极池中总酚和COD的去除率分别为92.5%和41.2%。同时，光催化-电芬顿双池氧化体系消耗电能为6.4 kW•h，阴极池和阳极池的电流效率分别为49.3%和10.7%。通过循环实验可知，Fe@Fe2O3/CF阴极和纳米TiO2/Ti阳极可分别重复使用5和7次。在最佳条件下，以苯醌（BQ）、叔丁醇（TBA）和超氧化物歧化酶（SOD）分别作为•O2-、•OH和H2O2的俘获剂，考察该耦合体系阴极室中罗丹明B的去除情况，在TBA，BQ和SOD存在下，观察到罗丹明B去除率分别为30.1%，90.9%和92.0%，这表明•OH是主要的反应性氧化物。综上，微生物燃料电池-电芬顿耦合体系的构建成功地解决了在不消耗外部能源的情况下同时处理两种废水的难题，是一种有前景的、清洁的污废水处理方法，为今后的工程推广提供了重要依据。