PMS/Fe^(0)体系中自由基产率比及莠去津降解动力学  

Radical production ratio and atrazine degradation kinetics in PMS/Fe^(0) system

作　　者：关英红 孙维敬 王盼盼 GUAN Yinghong;SUN Weijing;WANG Panpan(School of Water Conservancy and Civil Engineering,Northeast Agricultural University,Harbin 150030,China;School of Environment,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]东北农业大学水利与土木工程学院,哈尔滨150030 [2]哈尔滨工业大学环境学院,哈尔滨150001

出　　处：《哈尔滨工业大学学报》2022年第2期50-58,共9页Journal of Harbin Institute of Technology

基　　金：黑龙江省普通本科高等学校青年创新人才培养计划(UNPYSCT-2018166)。

摘　　要：针对水体中存在的难降解农药莠去津(ATZ)污染问题,提出零价铁活化过氧单硫酸盐(PMS/Fe^(0))降解水中的ATZ,研究不同工艺参数(溶液pH、PMS投加量、Fe^(0)投加量、ATZ初始浓度)条件下ATZ的降解动力学。采用硝基苯(NB)和ATZ竞争实验的方法,原位鉴定PMS/Fe^(0)体系的自由基种类,并进一步基于稳态假设定量推导得到自由基产率比的公式。最后,研究了模拟地下水条件下PMS/Fe^(0)对ATZ的降解规律。结果表明:ATZ降解的假一级速率常数(k_(obs)),随pH的增加而降低,随ATZ初始浓度的增加而降低,随Fe^(0)投量增加而增加,随PMS的投量先增加后降低,在PMS投量为25μmol/L时最大。NB和ATZ的竞争实验结果表明,PMS/Fe^(0)体系中的活性物种为硫酸根自由基(SO^(-)_(4)·)和羟基自由基(·OH),且两种自由基的产率比为10.5∶1。在模拟地下水条件下,Fe^(0)和PMS的投量为0.25 g/L和25μmol/L时,ATZ的降解率可达87%,说明模拟地下水水质背景下PMS/Fe^(0)对ATZ有很好的降解效果。研究结论可对PMS/Fe^(0)工艺修复受ATZ等农药污染地下水的工艺参数设计提供理论指导。In view of the frequent detection of atrazine(ATZ)in water body,which is a recalcitrant herbicide,zero-valent iron activated peroxymonosulfate(PMS/Fe^(0))was proposed to remove the ATZ in water.The effects of operation parameters(pH value,initial ATZ concentration,and PMS and Fe^(0) dosages)on ATZ degradation were investigated.Then the reactive species in PMS/Fe^(0) system were in-situ identified based on the competitive reactions of nitrobenzene(NB)and ATZ,and the formula for radical production ratio was derived under steady-state assumption.Finally,the degradation of ATZ by PMS/Fe^(0) was investigated under simulated groundwater condition.Results show that the pseudo-first order rate constant(k_(obs))of ATZ degradation decreased with increasing pH value and initial ATZ concentration,and increased with increasing Fe^(0) dosage.While it increased first and then decreased as the PMS dosage increased,reached the maximum at 25μmol/L PMS.The competition experiment shows that sulfate radical(SO^(-)_(4)·)and hydroxyl radical(·OH)were reactive species in PMS/Fe^(0) system,and the production ratio of the two radicals was calculated to be 10.5∶1.ATZ degradation efficiency could reach 87%at 0.25 g/L Fe^(0) and 25μmol/L PMS under simulated groundwater condition,indicating the prospective performance of PMS/Fe^(0) under groundwater conditions.The research results can provide theoretical reference for PMS/Fe^(0) applications in remediation of atrazine-polluted groundwater.

关 键 词：零价铁 莠去津 过氧单硫酸 硫酸根自由基 羟基自由基 地下水 

分 类 号：X523[环境科学与工程—环境工程]