Research Institute of Chemical Defense, Academy of Military Sciences, Beijing 102205, China.
Research Institute of Chemical Defense, Academy of Military Sciences, Beijing 102205, China; State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
J Hazard Mater. 2021 Apr 5;407:124808. doi: 10.1016/j.jhazmat.2020.124808. Epub 2020 Dec 9.
The degradation process of malathion in the acetyl peroxyborate (APB) solution of different APB/malathion molar ratio and in the carbonate-activated APB (APB/CO) solution of different pH was studied by P NMR technology. In the APB solution, all malathion could be degraded in 47.5 min when the molar ratio of APB/malathion was 60. CO could effectively activate APB to degrade all malathion in 10 min at pH of 10 when APB/malathion was 10, which was obviously higher than in APB solution. O, •O, •OH and carbon-centered radicals (RC•) could be produced in the APB/CO solution, and the degradation of malathion was mainly affected by RC•. The degradation mechanism of malathion in the APB/CO solution was proposed based on the research results of malathion degradation process by P NMR and active species quenching test, which involves two steps: the first step is the oxidation of malathion to malaoxon by RC•, and the second step is the hydrolysis of malaoxon to dimethyl phosphate via hydroxyl anions nucleophilic addition.
采用 P 核磁共振技术研究了不同过氧单乙酸酯（APB）/马拉硫磷摩尔比的 APB 溶液和不同 pH 值的碳酸盐激活的 APB（APB/CO）溶液中马拉硫磷的降解过程。在 APB 溶液中，当 APB/马拉硫磷摩尔比为 60 时，所有马拉硫磷在 47.5 分钟内均可降解。CO 在 pH 值为 10 时，当 APB/马拉硫磷摩尔比为 10 时，可有效激活 APB 使所有马拉硫磷在 10 分钟内降解，这明显高于 APB 溶液中的降解速度。在 APB/CO 溶液中可生成 O、•O、•OH 和碳中心自由基（RC•），马拉硫磷的降解主要受 RC•影响。基于 P 核磁共振和活性物质猝灭试验研究马拉硫磷降解过程的结果，提出了 APB/CO 溶液中马拉硫磷的降解机制，该机制涉及两个步骤：第一步是 RC•将马拉硫磷氧化为马拉氧磷，第二步是通过羟基阴离子亲核加成将马拉氧磷水解为二甲磷酸酯。
