阴阳极同步催化产生•OH/SO4•-及其降解有机磷酸酯类农药的研究

Electrochemical degradation technology is widely used in environmental pollution control fields. However, One disadvantage of the existing technology is that the current efficiency remains at a low level. Subsequently to the paired electro-generation of oxidizing agent in cathodic and anodic surface, the oxidizing agent will be in-situ catalyzed as the corresponding free radicals for removing organophosphorus pesticides in this project. Current efficiency is improved exponentially by the paired electro-generation of oxidizing agent in cathodic and anodic surface. Moreover, oxidants are utilized adequately by the in-situ catalysis of the oxidizing agent and catalysts are direct doped in the electrode so that the catalysts don’t have to be separated and recycled. Preliminary study confirmed H2O2 electro-generated was electro-catalyzed to •OH effectively by the improved gas diffusion cathode. Moreover, paired electro-generation of H2O2 and S2O82- were achieved, which establishes the foundation for sequential studies. In this project, Pd-Gas diffusion electrode will be used as cathode for electro-generating H2O2 and then for in- situ catalyzing H2O2 to •OH, and Pt- Transition metal oxides will be used as anode for the electro-generation of S2O82- and in-situ catalysis of S2O82- to SO4•- subsequently. Combined the above two electrode, the novel electrochemical degradation technology system is establish for removing organophosphorus pesticides. In-situ generating mechanism of •OH/SO4•-, interaction effect of the paired electro-generation and the subsequent catalysis in cathodic and anodic surface, electrochemical and dynamics behaviors of the organophosphorus pesticides are systematically investigated. This research will provide the theoretical foundation and implementation method for electrochemical techniques.

电化学降解技术广泛应用于环境污染治理领域，但现有电化学方法电流效率难以提高。本项目提出阴阳极成对合成与原位同步催化方法降解有机磷酸酯类农药。利用阴阳极成对电合成以成倍提高电流效率，同时原位催化增加氧化剂的利用效率，且催化剂直接掺杂在电极中无需分离回收，克服传统电化学法中电流效率低、氧化剂利用率不高等缺陷，具有显著优势。在前期验证了气体扩散阴极同步电催化生成•OH以及阴阳极成对高效合成H2O2/S2O82-的基础上，本项目拟开展以Pd-气体扩散电极为阴极合成H2O2并原位同步催化产生•OH，同时以过渡金属氧化物-Pt为阳极合成S2O82-并原位同步催化产生SO4•-，建立阴阳极成对合成与原位同步催化的电化学降解体系研究。考察•OH/SO4•-的原位生成机理，阴阳极同步催化过程中的相互影响机制，以及降解有机磷农药的电化学和动力学行为。研究成果将为发展高效低耗的电化学技术提供理论支撑和实施方法。

电化学降解技术是一种绿色的环境污染治理手段，但电流效率低限制了其推广应用。本项目提出阴阳极成对合成与原位同步催化方法降解有机磷酸酯类农药。利用阴阳极成对电合成以成倍提高电流效率，同时原位催化增加氧化剂的利用效率，克服了基于单极的传统电化学降解技术中电流效率低等关键缺陷，且催化剂直接掺杂在电极中无需分离回收，降低了反应成本，故此方法具有显著优势。. 本项目通过优化气体扩散电极实现了阴极高效合成H2O2并原位同步催化产生•OH，同时以BDD电极为阳极高效合成S2O82–并原位同步催化产生SO4•–。构建了阳极同步 成对合成H2O2和S2O82–并原位催化产生•OH/SO4•–的电化学氧化体系，并揭示了阴阳极同步合成过程中的相互影响机制。在阴阳极电解液循环运行模式中，阴阳极成对同步合成H2O2和S2O82–的总电流效率达到154.7%。当用于处理有机磷酸酯类农药毒死蜱时，阴阳极成对技术的电流效率比单极降解技术的电流效率提高了2~3倍。. 本体系不仅充分地利用了电合成的氧化剂，节约了投加氧化剂（H2O2、S2O82–）的成本，而且极大的提高了实际电流效率，具有很高的实际应用价值，为解决电化学法降解有机物的关键性问题提供理论依据。该体系在有机污染物的高级氧化处理应用方面具有很大的发展潜力，不仅拓宽和完善原位电化学降解技术的应用范围，而且降低其能耗和成本，兼顾环保与节能目标。