Kinetics and mechanism for degradation of dichlorvos by permanganate in drinking water treatment
Kinetics and mechanism for degradation of dichlorvos by permanganate in drinking water treatment
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饮用水处理中高锰酸盐降解敌敌畏的动力学和机制
DOI：
10.1016/j.watres.2009.05.001
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发表时间：
2009-08-01
期刊：
影响因子：
12.8
通讯作者：
Zhang, Tao
中科院分区：
文献类型：
--
作者：
Liu, Chao;Qiang, Zhimin;Zhang, Tao
研究了饮用水处理过程中高锰酸盐对敌敌畏的降解动力学和机理。敌敌畏与高锰酸盐的反应为二级反应，pH依赖性可忽略，活化能为29.5 kJ·mol（-1）。在pH 7.0和25 ℃下，速率常数为25.2 +/- 0.4 M-1 s（-1）。敌敌畏首先同时降解为磷酸三甲酯（TMP）和磷酸二甲酯（DMP），分别约占磷质量的= 95%。进一步的氧化生成最终的副产物，磷酸单甲酯（MMP）。MMP首次被鉴定为敌敌畏化学氧化的主要副产物。基于降解机理和确定的反应速率常数的动力学模型，使我们能够预测敌敌畏及其副产物的高锰酸盐预氧化过程中的水处理厂的浓度演变。这些结果表明，即使敌敌畏在地表水中的浓度符合中国的地表水质量标准（50 μ g L-1），其浓度在常规水处理后将很可能超过饮用水质量标准（1 μ g L-1）。发光细菌试验表明，敌敌畏溶液经高锰酸盐氧化后，其急性毒性明显增强。(C)2009爱思唯尔有限公司保留所有权利。
The degradation kinetics and mechanism of dichlorvos by permanganate during drinking water treatment were investigated. The reaction of dichlorvos with permanganate was of second-order overall with negligible pH dependence and an activation energy of 29.5 kJ.mol(-1). At pH 7.0 and 25 degrees C, the rate constant was 25.2 +/- 0.4 M-1 s(-1). Dichlorvos was first degraded to trimethyl phosphate (TMP) and dimethyl phosphate (DMP) simultaneously which approximately accounted for = 95% with respect to phosphorus mass, respectively. Further oxidation of DMP generated a final byproduct, monomethyl phosphate (MMP). MMP was for the first time identified as a major byproduct in chemical oxidation of dichlorvos. The kinetic model based on degradation mechanism and determined reaction rate constants allowed us to predict the evolution of dichlorvos and its byproduct concentrations during permanganate pre-oxidation process at water treatment plants. These results suggest that even though the dichlorvos concentration in surface water complies with the surface water quality standards of China (50 mu g L-1), its concentration after conventional water treatment will most probably exceed the drinking water quality standards (1 mu g L-1). Moreover, luminescent bacteria test shows that the acute toxicity of dichlorvos solution evidently increased after permanganate oxidation. (C) 2009 Elsevier Ltd. All rights reserved.