电化学活化过氧乙酸灭活水中大肠杆菌  

Inactivation of E.coli in water by electrochemical activation of peracetic acid

作　　者：蒋励铭 卞静 张晓晖 向俊颖 钟艺华 赵纯[1] JIANG Li-ming;BIAN Jing;ZHANG Xiao-hui;XIANG Jun-ying;ZHONG Yi-hua;ZHAO Chun(Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment,Ministry of Education,Chongqing University,Chongqing 400045,China;Department of Gastroenterology,Chongqing University Cancer Hospital,School of Medicine,Chongqing University,Chongqing 400030,China)

机构地区：[1]重庆大学三峡库区生态环境教育部重点实验室,重庆400045 [2]重庆大学医学院附属重庆大学肿瘤医院消化内科,重庆400030

出　　处：《中国环境科学》2023年第8期3966-3973,共8页China Environmental Science

基　　金：国家自然科学基金资助项目(22076015);重庆市医学科研项目(2021MSXM083)。

摘　　要：以大肠杆菌为目标微生物,通过引入电场提高过氧乙酸的氧化能力,研究了电化学活化过氧乙酸体系对大肠杆菌的灭活效果.分别探究了过氧乙酸浓度、电流强度、初始pH值以及水体中背景物质(HA、Cl^(-)、HCO_(3)^(-)和PO_(4)^(3-))等对大肠杆菌灭活的影响并分析了电化学活化过氧乙酸体系中存在的活性物种以及大肠杆菌失活过程.电化学活化过氧乙酸体系对大肠杆菌的灭活具有明显的协同效果,相比于单独过氧乙酸处理,在10min内对大肠杆菌的对数去除率提高了2.24log.增大过氧乙酸浓度和电流强度均可以提高大肠杆菌对数去除率,但电流强度增加到一定限度时对大肠杆菌对数去除率的提升效果减弱.酸性条件比碱性条件更有利于大肠杆菌灭活,在pH值为3时效果最佳.Cl^(-)对电/过氧乙酸体系灭活大肠杆菌具有明显的促进作用,而HA、HCO_(3)^(-)和PO_(4)^(3-)对大肠杆菌灭活存在一定抑制作用.自由基淬灭实验表明,在电化学活化过氧乙酸体系中存在·OH和R^(-)O·,·OH对大肠杆菌灭活的贡献比R^(-)O·更高.对大肠杆菌失活过程的探究表明,大肠杆菌细胞壁和细胞膜最先被破坏,胞内物质流出,然后逐步被分解成碎片,细胞完全失活.The inactivation of E.coli was studied by introducing electric field to improve the oxidation capacity of peracetic acid.The effects of peracetic dosage,current intensity,initial pH value and water matrix(HA、Cl_(-)、HCO_(3)^(-)and PO_(4)^(3-))on the inactivation of E.coli were investigated respectively.Besides,the active species and the inactivation process of E.coli were systematically analyzed.The electrochemical activation of peracetic acid showed obvious synergistic effect on the inactivation of E.coli.Compared with peracetic acid alone,the inactivation of E.coli increased by 2.24 log within 10min.Increasing the peracetic acid dosage and current intensity could improve the inactivation of E.coli.However,when the current intensity increased to a threshold,the improvement on the inactivation of E.coli was negligible.Acidic conditions facilitated the inactivation of E.coli,and the optimal condition of pH was at 3.Cl-obviously promoted the inactivation of E.coli,while HA、HCO_(3)^(-)and PO_(4)^(3-)inhibited the inactivation process.Free radical quenching experiments evidenced that·OH and R^(-)O·existed in the electrochemical activation of peracetic acid,while the·OH played the major role in the inactivation of E.coli.The study of the inactivation mechanism of E.coli revealed that the cell wall and membrane were destroyed at first.Then,the intracellular material flowed out.Eventually,the cells were gradually broken down into fragments and completely inactivated.

关 键 词：过氧乙酸 大肠杆菌 羟基自由基 电化学 

分 类 号：X172[环境科学与工程—环境科学]