含乐果废水的循环电-Fenton氧化过程及其影响因素  

Oxidation treatment of dimethoate-containing wastewater by a circulating electro fenton method

作　　者：吴进华[1] 李小明[1] 曾光明[1] 杨麒[1] 黄昱[1] 易婷[1] 

机构地区：[1]湖南大学环境科学与工程学院,长沙410082

出　　处：《环境科学学报》2008年第8期1534-1541,共8页Acta Scientiae Circumstantiae

基　　金：国际科技合作重点项目(No2004DFA06200);新世纪优秀人才支持计划资助(NoNCET-04-0770)~~

摘　　要：为克服传统Fenton(Conventional Fenton,简称CF)法中存在着Fe2+在反应初始时即被氧化且反应过程中产生大量铁泥(Fe的复杂络合物)的不足,研究了循环电-Fenton(Circulating Electro Fenton,简称CEF-FeRe)法氧化降解自配乐果废水的过程及其各影响因子的作用机制.CEF-FeRe反应所需的H2O2通过蠕动泵缓慢加入到电解池中,而被氧化了的Fe2+又在阴极被还原,使得Fenton反应能持续进行.在乐果浓度为200mg·L-1时,通过多个单因素试验确定最佳CEF-FeRe反应条件为:常温、pH值为3.0、H2O2/Fe2+的摩尔比为10、H2O2的加入量为理论剂量、恒流0.5A.结果表明,在此条件下反应120min后COD去除率为81.67%,乐果在25min内去除率为99.4%.通过测定CEF-FeRe以及CF反应过程中Fe2+和H2O2的变化情况验证了CEF-FeRe反应的机理.动力学研究结果表明,乐果废水的CEF-FeRe反应符合一级动力学反应规律.CEF-FeRe法处理实际乐果废水也可以得到91.16%的乐果去除及68.53%的COD去除,这表明CEF-FeRe法处理乐果废水效率高且运行费用较低的特点.The main disadvantage of Conventional Fenton （CF） treatment is the lack of Fe^2 ＋ due to the rapid oxidation of Fe^2 ＋ to Fe^3 ＋ . To solve this problem, a Circulating Electro-Fenton reactor （CEF-FeRe） was employed to degrade dimethoate, during which H2O2was added to the electrolytic cell continuously by a peristaltic pump and Fe^2＋ could be regenerated to Fe^3＋ on the cathode. The operating conditions for this CEF-FeRe, such as pH value, electric current, Fenton reagent dosage, and the molar ratio of Fe^2＋ to H2O2, were optimized by individual factor experiments. The research results showed that the optimal conditions for dimethoate （200 mg· L ^-1 ） degradation are ： pH = 3.0, n （ Fe^2＋ ）/n （ H2 O2 ） = 0.1, electric current = 0.5 A and Fenton＇s reagent dosage at its theoretical dosage. Under these conditions, COD removal rates reached 81.67% within 120 min, while 99. 4% of dimethoate was degraded within 25 min. The mechanism of the CEF-FeRe reaction was investigated by monitoring the changes of H2 O2 and Fe2. concentration during the process. Kinetics results revealed that dimethoate oxidation follows the pseudo-first-order kinetic model at different pH values. Treatment of actual dimethoate wastewater by the CEF-FeRe showed that the removal rates of dimethoate and COD were about 91.16% and 68.53% , respectively, which indicated that the CEF-FeRe could be a cost-efficient method for dimethoate degradation.

关 键 词：CEF-FeRe法 乐果 一级反应动力学 反应机理 

分 类 号：X703[环境科学与工程—环境工程]