均相Co/PMS系统降解吡虫啉的影响因素及降解途径研究  

Influential Factors and Degradation Pathway of Imidacloprid by Homogeneous Co/PMS System

作　　者：陈晓旸[1] 陈景文[1] 杨萍[1] 乔显亮[1] 

机构地区：[1]大连理工大学环境科学与工程系

出　　处：《环境科学》2007年第12期2816-2820,共5页Environmental Science

基　　金：国家重点基础研究发展规划(973)项目(2003CB415006)

摘　　要：过渡态Co2+催化分解KHSO5(Co/PMS)系统是一种新型的高级氧化技术,其反应体系可以产生强氧化性的硫酸自由基(SO4.-).以杀虫剂吡虫啉为目标污染物,重点研究了溶液中PMS浓度、Co2+浓度和无机阴离子(H2PO4-、HCO3-、NO3-和Cl-)对Co/PMS系统降解吡虫啉的影响.结果表明,吡虫啉的降解遵循准一级动力学,其降解速率与氧化剂PMS浓度和催化剂Co2+的浓度呈正相关.吡虫啉的降解速率随着PMS和Co2+浓度的增加而增大,但是当PMS与吡虫啉的摩尔比大于20时,增加PMS的浓度对吡虫啉的降解速率反而有一定程度的抑制.H2PO4-能促进Co/PMS系统对虫啉的降解;低浓度的HCO3-促进吡虫啉的降解,高浓度则为抑制作用;Cl-抑制吡虫啉的降解,而NO3-则对整个降解过程影响不明显.研究中采用GC/MS分析吡虫啉降解的中间产物,得到了6-氯烟酸和6-氯烟酰胺2种主要的中间产物,并由此推测其可能的降解途径.Cobahous-mediated decomposition of peroxymonosulfate （Co/PMS） system is one of novel advanced oxidation technologies （AOTs）, which leads to the formation of very strong oxidizing species in aqueous phase. Effects of PMS concentrations, Co^2＋ concentrations and various inorganic anions （H2PO4^- , HCO3^- , NO3^- , Cl^- ） on the degradation of Imidacloprid induced by Co/PMS system was investigated as emphasis. The degradation kinetics of imidacloprid followed pseudo first-order kinetics and reaction rates related to PMS and Co^2＋ concentrations. The reaction rates increased with increasing [ PMS] and [ Co^2＋ ] when the other parameters were constant. However, the decrease of degradation rates was found when the molar ratio of PMS versus imidacloprid was over 20. The effects of H2 PO4- had positive effect on the degradation of Imidacloprid, low concentration HCO3^- had positive effect and high concentration HCO; had negative effect, Cl^- had negative effect, while NO3^- had little effect. Based on the results of GC/MS, two main intermediates were identified, 6-chloronicotinic acid and 6-chloronicotinamide, and the reaction pathway for SO4^- induced by homogeneous Co/PMS was proposed accordingly.

关 键 词：高级氧化技术(AOTs) 硫酸自由基 无机离子 降解机理 废水处理 吡虫啉 

分 类 号：X703[环境科学与工程—环境工程]