避免有毒中间产物产生的草甘膦光催化降解策略与机理研究

针对草甘膦安全降解挑战性难题——避免生成毒性更大、更难降解的氨甲基膦酸(AMPA)中间产物的研究具有重要意义。本项目拟通过氟化改性金属氧化物F-MOx(F-TiO2、F-ZnO、F-InVO4、F-BiOX (X=F, Cl, Br))的表面和次层结构，达到催化剂既能保证和草甘膦的N-C-PO3H2端的配位活化打断N-C或C-P键，走肌氨酸和正磷酸中间产物路线，且不需外加无机电解质以抑制金属氧化物MOx固有的优先和草甘膦N-C-COOH端有利的配位作用，避免产生有毒AMPA中间产物。系统探索F-MOx氟化改性的方法以及表层和次层F代O的程度等因素与降低AMPA产率的构效关系；研究在不加无机电解质的情况下，F-MOx光催化降解草甘膦的反应特性，用ESR、ATR-FTIR等手段表征草甘膦N-C-PO3H2端与F-MOx表面的配位和催化活化反应机理。为安全降解水体中草甘膦提供理论依据和技术支持。

It is a challenge but scientifically and practically significant to develop a new approach avoiding the formation of toxic and refractory Aminomethylphosphonic acid (AMPA) as an intermediate during the degradation of glyphosate. In this project, we intend to activate the coordination part of N-C-PO3H2 in glyphosate, when adsorbed on transition metal oxide catalysts with fluorine modified surface and sub-surface F-MOx (F-TiO2, F-ZnO, F-InVO4, F-BiOX (X=F, Cl, Br)), so that N-C or C-P bond would be broken to produce sarcosine and orthophosphate with no addition of concentrated inorganic electrolyte to suppress or prohibit the inherent preferred coordination of metal oxide with glyphosate by its N-C-COOH part, which will lead to intermediate AMPA. To achieve this goal, we plan to systematically study the structure-activity relationships between the yield of AMPA and fluorine modification strategies, and the extent of F/O-substitution of F-MOx; to draw out the degradation characteristics of glyphosate over F-MOx without the presence of concentrated inorganic electrolyte; to monitor and reveal the coordination and the activate mechanism of N-C-PO3H2 with F-MOx by using in-situ ESR, ATR-FTIR and other methods. All the results are to provide theoretical basis and technical support for the degradation of glyphosate in water safely and effectively.