共存电子受体对微米铁-微生物耦合还原地下水中三氯乙烯过程的影响  

Effect of coexisting electron acceptors on trichloroethylene reduction in groundwater via microscale zero-valent iron and microorganism coupling system

作　　者：陈丽君 王晓慧 袁梦姣 赵芳 王丽涛 辛佳 CHEN Lijun;WANG Xiaohui;YUAN Mengjiao;ZHAO Fang;WANG Litao;XIN Jia(Key Lab of Marine Environmental Science and Ecology,Ministry of Education,Ocean University of China,Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering,Ocean University of China,College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100)

机构地区：[1]中国海洋大学海洋环境与生态教育部重点实验室,中国海洋大学山东省海洋环境地质工程重点实验室,中国海洋大学环境科学与工程学院,青岛266100

出　　处：《环境科学学报》2024年第5期253-263,共11页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金面上项目(No.41877176)。

摘　　要：近年来,对氯代烃类污染地下水进行修复是亟待开展的工作.微米铁(microscale zero-valent iron,mZVI)-微生物耦合技术可充分实现化学还原和微生物还原作用的优势互补,具有良好的应用前景.然而,由于实际地下水成分复杂,共存电子受体(如NO_(3)^(-)和SO_(4)^(2-))可能与目标污染物竞争电子或影响ZVI和微生物的活性,降低体系对目标污染物的修复效果.鉴于此,本研究拟以典型氯代烃三氯乙烯(trichloroethylene,TCE)为目标污染物,以NO_(3)^(-)、SO_(4)^(2-)为代表性共存电子受体,依托批量实验探究不同水化学条件下耦合体系的TCE去除效率和电子效率.研究表明相比于TCE为唯一电子受体的对照组,各浓度水平的NO_(3)^(-)均降低TCE去除率和产物的完全脱氯率(CDR),有毒害作用的氯代中间产物(二氯乙烯cis-DCE、trans-DCE、1,1-DCE)占比较大;各浓度水平SO_(4)^(2-)均能提高TCE去除速率,低、中浓度SO_(4)^(2-)共存时TCE更倾向于生成清洁产物(乙烯C_(2)H_(4)、乙烷C_(2)H_(6)、乙炔C_(2)H_(2)和多碳产物C_(3)~C_(6)),而高浓度SO_(4)^(2-)共存组产物脱氯程度低.NO_(3)^(-)和SO_(4)^(2-)共同存在时,与各自单一存在时相比,TCE去除率和电子效率进一步下降,但CDR值较高.NO_(3)^(-)、SO_(4)^(2-)均占据还原当量使体系的电子效率下降,且共存电子受体浓度越高电子流失越严重.Remediation of chlorinated hydrocarbon-contaminated groundwater has become a increasing urgent issue in recent years.The coupling microscale zero-valent iron(mZVI) with microorganisms has been considered as an attractive method for groundwater remediation,combining the both advantages.However,due to the complex composition of groundwater,coexisting electron acceptors(e.g.,NO_(3)^(-)and SO_(4)^(2-)) may compete for electrons with the target contaminants or affect the reactivity of ZVI and microorganism to inhibit TCE removal.This study used a representative chlorinated hydrocarbon trichloroethylene(TCE) as the target contaminant and NO_(3)^(-),SO_(4)^(2-)as the coexisting natural electron acceptors,aiming to explore the TCE removal efficiency and electron efficiency of the coupling system under different groundwater hydrochemical scenarios.Compared with the control group with TCE as the only electron acceptor,the presence of NO_(3)^(-)led to a decrease in TCE removal and increased the proportion of toxic chlorinated intermediates(cis-DCE,trans-DCE,1,1-DCE) across all three tested concentration levels.In scenario of SO_(4)^(2-) co-existence,TCE was more likely to be transformed into non-chlorinated products(C_(2)H_(4),C_(2)H_(6),C_(2)H_(2) and C_(3)~C_6) with SO_(4)~2 at low and medium concentrations,whereas incomplete dechlorination was more significant with SO_(4)^(2-) at a high concentration.In cases where both NO_(3)^(-)and SO_(4)^(2-) coexisted and competed for electrons,the electron efficiency was significantly lower than those with only one coexisting electron acceptor,although the complete dechlorination ratio was higher.

关 键 词：微米铁 微生物 三氯乙烯 共存电子受体 电子效率 完全脱氯率 

分 类 号：X524[环境科学与工程—环境工程]