相对湿度条件下二氧化锰对甲基对硫磷的转化行为  

Transformation behavior of methyl parathion by manganese dioxide under relative humidity conditions

作　　者：雷蒙 曹瑾如 周超群 张彩香[2] 廖小平 LEI Meng;CAO Jinru;ZHOU Chaoqun;ZHANG Caixiang;LIAO Xiaoping(Wuhan Institute of Technology,Wuhan 430205,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences(Wuhan),Wuhan 430078,China)

机构地区：[1]武汉工程大学化学与环境工程学院,湖北武汉430205 [2]中国地质大学(武汉)生物地质与环境地质国家重点实验室,湖北武汉430078

出　　处：《安全与环境工程》2024年第2期274-281,共8页Safety and Environmental Engineering

基　　金：国家自然科学基金项目(41702267);武汉工程大学科学基金项目(K201935);武汉工程大学研究生创新基金项目(CX2022423)。

摘　　要：以不同晶型的二氧化锰(MnO_(2))为试验材料,探讨了相对湿度(relativehumidity,RH<5%~100%)条件下MnO_(2)对典型有机磷农药甲基对硫磷的转化行为。结果显示:甲基对硫磷的一级降解速率与RH呈明显负相关性,与MnO_(2)含量呈明显正相关性;不同晶型MnO_(2)对反应体系中甲基对硫磷的降解行为差异较大,其一级动力学降解反应速率常数(kobs)顺序为α-MnO_(2)>γ-Mn O_(2)>β-Mn O_(2);负载离子(PO_(4)^(3-)、Ca^(2+)和Mn^(2+))都能明显抑制甲基对硫磷的降解反应速率,其中Mn^(2+)的抑制效果最为显著;RH条件下Mn O_(2)对甲基对硫磷的转化路径主要包括水解和氧化,水解产物为对硝基苯酚,氧化产物为甲基对氧磷。本研究结果证实了实际土壤层RH显著影响锰氧化物对有机磷农药的转化行为,对理解天然环境中该类污染物的归趋行为具有参考价值。This paper investigates the transformation behavior of manganese dioxide(MnO_(2))to the typical organophosphorus pesticide methyl parathion under relative humidity(RH<5%~100%)conditions.The results show that the primary degradation rate of methyl parathion shows a significant negative correlation with RH,but a significant positive correlation with MnO_(2) content by using different crystal types of MnO_(2) as the materials.The degradation behavior of methyl parathion in the reaction system varies widely among different crystalline types of MnO_(2),and the first-order kinetic degradation rates(k_(obs))are in the order of α-MnO_(2)>γ-MnO_(2)>β-MnO_(2).The loading ions(PO_(4)(3-),Ca^(2+)and Mn^(2+))investigated all significantly inhibit the degradation reaction rate of methyl parathion,among which,Mn^(2+)has the most significant inhibition effect.The transformation pathway of methyl parathion by MnO_(2) under RH conditions mainly consists of hydrolysis and oxidation,with the hydrolysis product being p-nitrophenol and the oxidation product being methyl paraoxon.The results of this study confirm that RH of the actual soil layer significantly affects the transformation behavior of manganese oxides towards organic phosphorus pesticides,which has reference value for understanding the fate behavior of such pollutants in the natural environment.

关 键 词：二氧化锰 甲基对硫磷 相对湿度 转化行为 

分 类 号：X5[环境科学与工程—环境工程]