微酸性电解水对溶液体系中有机磷农药的降解机制及途径分析研究

Study on the degradation mechanism and pathway of chlorpyrifos by slightly acidic electrolyzed water in aqueous system

目的研究对硫磷、甲基对硫磷和乐果对微酸性电解水的敏感性,检测其降解产物并推断降解过程。方法以对硫磷、甲基对硫磷和乐果标准品单一组分为研究对象,通过调节反应时间、微酸性电解水有效氯浓度和有机磷农药的初始浓度,采用气相色谱-质谱联用法检测有机磷农药的降解产物。对有机磷农药在微酸性电解水主要活性成分次氯酸和羟自由基作用下的降解途径进行了分析。结果在反应时间30 s下,有效氯浓度为5.66 mg/L时,对硫磷、甲基对硫磷和乐果的降解率均能达到100%。并检测到对硫磷和甲基对硫磷的直接降解产物对氧磷和甲基对氧磷。结论微酸性电解水能够有效降解有机磷农药,并对HOCl和·OH共同作用于有机磷农药这一降解途径做出假设。该研究对于电解水在消除果蔬有机磷农药残留的应用具有一定的理论意义。

Objective To study the sensitivity of parathion, methyl parathion and dimethoate to slightly acidic electrolyzed water respectively, detect the degradation products and infer the degradation process. Methods Taking parathion, methyl parathion and dimethoate as the research objects, the degradation products of organophosphorus pesticides were detected by gas chromatography-mass spectrometry(GC-MC) by adjusting the reaction time, the available chlorine concentration(ACC) of slightly acidic electrolyzed water and the initial concentration of organophosphorus pesticides. The hypothesis degradation pathway of organophosphorus pesticides under the combination influence of hypochlorous acid and hydroxyl radical(·OH) was analyzed. Results When the reaction time was 30 s and the ACC was 5.66 mg/L, the degradation rate of parathion, methyl parathion and dimethoate reached 100%. The direct degradation products of parathion and methyl parathion, paraoxon and methyl paraoxon were detected. Conclusion Slightly acidic electrolyzed water can effectively degrade organophosphorus pesticides, and it is assumed that HOCl and ·OH act together on the degradation pathway of organophosphorus pesticides. The research has certain theoretical significance for the application of electrolyzed water in eliminating organic phosphorus pesticide residues in fruits and vegetables.