三维复合孔道SnO2去除难降解有机物的脉冲电吸附-电催化氧化协同机制

A three-dimensional complex porous SnO2 electrode with both high electrosorptive and electrocatalytic activity was firstly proposed for efficient removal of refractory organic pollutants. The structure control method of hierarchical macro-mesoporous SnO2-Sb electrodes will be obtained from the structural design of porous materials in our project, and this project focuses on the synergetic mechanism of pulse electro-sorption and electro-oxidation for removal of refractory organic pollutants. The influences of complex porous structure of SnO2-Sb electrodes on the electrochemical performance are studied to interpret their structure-activity relationship. The internal relationship of pulse electro-sorption and electro-oxidation for complex porous SnO2-Sb electrode are investigated to achieve efficiently synergetic removal of refractory organic pollutant. Interface reaction mechanism including degradation pathway of target pollutants, competitive electro-sorption of degradation intermediates and pulse microreaction process are studied in detail for three-dimensional complex porous SnO2-Sb electrode, which is vital to reveal the synergetic mechanism of pulse electro-sorption and electro-oxidation integrated process. Through these researches, both regeneration problem for electro-sorption and difficult problem for electro-oxidation controlled by mass transfer will be resolved, and new materials and methods for efficient removal of refractory organic pollutant will be provided.

本项目提出将同时兼备优良电吸附和电催化性能的三维复合孔道SnO2电极应用于难降解有机污染物高效去除的研究设想，从多孔材料的结构设计出发，获得大孔-介孔梯级SnO2-Sb电极的结构控制方法，重点围绕脉冲电吸附-电催化氧化技术去除难降解有机物的协同机制展开研究。通过研究SnO2-Sb电极孔道形态对其电化学性能的影响，诠释三维复合孔道SnO2-Sb电极的构效关系；分析复合孔道SnO2-Sb电极的脉冲电吸附-电催化氧化技术的内在关联规律，实现脉冲电吸附-电催化氧化对难降解有机物高效的协同降解处理；通过分析目标污染物的降解历程、降解产物的竞争电吸附特性及脉冲微观反应过程，研究三维复合孔道SnO2-Sb电极表面的界面反应机制，揭示其降解目标物的脉冲电吸附-电催化氧化协同机制。通过这些科学问题的探索，同时解决电吸附的再生问题和电化学氧化扩散控制的难点问题，为难降解有机污染物的高效去除提供新材料和新方法。

本项目成功制备了钛基TiO2纳米管/三维复合孔道SnO2-Sb电极，分析了不同复合孔道结构电极的电化学性能。电极的复合孔道形态对其电化学性能具有重要的影响。在乙醇溶剂浓度为50%的条件下，制备的三维复合孔道SnO2-Sb电极的孔道结构最佳。由于其大孔-介孔梯级结构复合孔道特征，TNTs/3D-SnO2-2电极具有较高的比表面积，较大的电化学活性点和较低的电化学阻抗。诠释了三维复合孔道SnO2-Sb电极的电化学性能强化机制，电极电催化氧化性能的提高归功于其产生羟基自由基以及传质能力的改善。构建了新型的脉冲电吸附-电催化氧化技术体系，分析了复合孔道SnO2-Sb电极的脉冲电吸附-电催化氧化技术的内在关联规律，实现脉冲电吸附-电催化氧化对难降解有机物高效的协同降解处理。脉冲电吸附-电催化氧化过程的反应速率常数，相比脉冲电催化氧化和直流电催化氧化，分别提高至1.8倍和2.5倍，大大提高了苯甲酸的电催化氧化去除效率。阐明了脉冲电吸附-电催化氧化的微观反应过程及协同机制。电极和污染物之间的强化接触，瞬时电流的提高和中间产物的低量积累都在脉冲电吸附-电催化氧化技术降解污染物中起到了重要的强化作用。脉冲电吸附-电催化氧化技术体系在难降解有机废水处理中具有广阔的应用前景。