摘要
三氯乙烯(TCE)是地下水中分布较普遍且难以降解的一类污染物,具有密度大、迁移能力强、相对持久及生物难降解等性质,常见的地下水修复技术存在TCE去除效率低、成本高的问题。此外,在大多数TCE污染场地地下水中常发现有氯代烃稳定剂1,4-二恶烷(1,4-D)的伴生污染且难以综合去除。当前,基于过硫酸盐的高级氧化技术因其高效、经济、环境友好等优点备受青睐,是一种降解有机污染最有效的技术之一。研究以铁碳原电池(n ZVI/C)为活化剂,过氧化钙(CP)为增强剂,柠檬酸/过硫酸钠(CA/PS)为氧化剂构建了一种新型的微电解-氧化耦合技术体系(n ZVI/C/CP-CA/PS)探究水中高浓度TCE的降解。考察了不同修复体系类型、药剂投加比、间隔投放时间及反应温度对降解TCE的影响,并初步探究了耦合体系对TCE及1,4-D复合污染的去除效果。试验结果表明:在室温为20℃,间隔时间为3h,活化剂n ZVI/C、增强剂CP与氧化剂CA/PS摩尔投加比为35∶0.5∶26的条件下,初始质量浓度为10000μg/L的TCE经n ZVI/C/CP-CA/PS耦合体系处理6h后,出水浓度满足了《地下水质量标准》(GB/T14848—2017)中Ⅳ类水要求,去除率接近100%。降解机制说明TCE在活性炭吸附及n ZVI/C/CP原电池的还原脱氯作用下优先发生部分降解,随后通过原电池及其产物进一步活化CA/PS氧化剂产生·OH和SO_(4)·^(-)等强氧化性自由基起到深度降解的目的,从而使TCE的浓度进一步降低,且降解过程符合零级反应动力学。该试验表明n ZVI/C/CP-CA/PS耦合体系对高浓度TCE的降解兼具高效及经济双重优势,并在TCE及1,4-D复合污染场地的修复中具有较大的应用潜力,有助于推进该耦合体系在有机污染水处理行业的应用与发展。
Trichloroethylene(TCE)is a typical pollutant which is widely distributed in groundwater and difficult to degrade.It has the properties of high density,strong migration ability,relatively durable and difficult to biodegrade.Common groundwater remediation techniques have the problems of low TCE removal efficiency and high cost.In addition,the associated pollution of chlorinated hydrocarbon stabilizer 1,4-dioxane(1,4-D)is often found in groundwater of most TCE contaminated sites and is difficult to be removed comprehensively.At present,the advanced oxidation technology based on persulfate is favored because of its high efficiency,economy and environmental friendliness,and is one of the most effective technologies to degrade organic pollution.In this study,a new microelectrolysis-oxidation coupling technology system(nZVI/C/CP-CA/PS)was constructed with iron carbon galvanic cell(nZVI/C)as activator,calcium peroxide(CP)as enhancer and citric acid/sodium persulfate(CA/PS)as oxidant to investigate the degradation of high concentration TCE in water.The effects of different remediation systems,dosage ratio,interval time and reaction temperature on the degradation of TCE were investigated,and the removal effect of the coupled system on TCE and 1,4-D composite pollution was initially explored.The results showed that:TCE with an initial mass concentration of 10000μg/L was treated by nZVI/C/CP-CA/PS coupling system for 6 h at room temperature of 20℃for an interval of 3 h,and the molar ratio of activator nZVI/C,enhancer CP and oxidizer CA/PS was 35∶0.5∶26.The effluent concentration met the requirements of ClassⅣwater in the Standard for Groundwater Quality(GB/T 14848—2017),and the removal rate was close to 100%.The degradation mechanism indicated that TCE was partially degraded by adsorption of activated carbon and reduction dechlorination of nZVI/C/CP enhanced primary cell.Then,CA/PS oxidants were further activated by the galvanic cell and its products to produce strong oxidizing free radicals such as·OH and SO·_(
作者
贺妮
肖劲光
冯闯
刘喜
肖武
HE Ni;XIAO Jinguang;FENG Chuang;LIU Xi;XIAO Wu(PowerChina Environmental Engineering Co.,Ltd.,Changsha 410014,China;PowerChina Zhongnan Engineering Co.,Ltd.,Changsha 410014,China)
出处
《净水技术》
CAS
2024年第9期98-104,共7页
Water Purification Technology
基金
湖南省自然科学基金项目(2017JJ2296)
湖南省环保科研课题(HBKT-2021008)。
