Abiotic degradation of methyl parathion by manganese dioxide: Kinetics and transformation pathway
Abiotic degradation of methyl parathion by manganese dioxide: Kinetics and transformation pathway
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二氧化锰非生物降解甲基对硫磷：动力学和转化途径
DOI：
10.1016/j.chemosphere.2016.02.028
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发表时间：
2016-05-01
期刊：
影响因子：
8.8
通讯作者：
Zhu, Zhenli
中科院分区：
文献类型：
--
作者：
Liao, Xiaoping;Zhang, Caixiang;Zhu, Zhenli
甲基对氧磷是一种在世界范围内广泛使用的杀虫剂，由于其降解产物甲基对氧磷对哺乳动物毒性大、毒性强等特点，逐渐引起了研究者的广泛关注。鉴于二氧化锰（MnO 2）在土壤和水体沉积物中的普遍存在，采用间歇实验研究了α-MnO 2对甲基对硫磷的非生物降解。结果表明，α-MnO 2在30 h内对甲基对硫磷的降解率可达90%，且甲基对硫磷的去除率与α-MnO 2的负载量和溶液的pH值密切相关，反应符合拟一级动力学模型。金属离子（如Ca ~（2+）、Mg ~（2+）和Mn ~（2+））的共存显著削弱了α-MnO_2对甲基对硫磷的降解。而溶解性有机物（HA-Na）对反应速率的影响表现为两个方面：提高甲基对硫磷的水解速率，但降低甲基对硫磷的氧化速率。基于气相色谱-质谱（GC/MS）和液相色谱-高分辨质谱（LC/HRMS）分析的降解产物，提出水解和氧化过程是α-MnO 2降解甲基对硫磷的两种主要反应机理。本研究为阐明环境中锰氧化物矿物对甲基异硫氰酸根离子的非生物耗散提供了有意义的信息。(C)2016爱思唯尔有限公司版权所有
Methyl parathion, a widely used insecticide around the world, has aroused gradually extensive concern of researchers due to its degradation product such as methyl paraoxon, with higher toxicity for mammals and more recalcitrant. Given the ubiquity of manganese dioxide (MnO2) in soils and aquatic sediments, the abiotic degradation of methyl parathion by alpha-MnO2 was investigated in batch experiments. It was found that methyl parathion was decomposed up to 90% by alpha-MnO2 in 30 h and the removal efficiency of methyl parathion depended strongly on the loading of alpha-MnO2 and pH value in the solution where the reactions followed pseudo-first-order model well. The coexisting metal ions (such as Ca2+, Mg2+ and Mn2+) weakened markedly the degradation of methyl parathion by alpha-MnO2. However, the effect of dissolved organic matter (HA-Na) on reaction rates presented two sides: to improve hydrolysis rate but deteriorate oxidation rate of methyl parathion. Based on the degradation products identified by gas chromatography-mass spectrometer (GC/MS) and liquid chromatography high-resolution mass spectrometer (LC/HRMS), both hydrolysis and oxidation processes were proposed to be two predominant reaction mechanisms contributing to methyl parathion degradation by alpha-MnO2. This study provided meaningful information to elucidate the abiotic dissipation of methyl parathion by manganese oxide minerals in the environment. (C) 2016 Elsevier Ltd. All rights reserved.