环境pH条件下Fe^(2+)活化过二硫酸盐降解有机污染物的效能与影响因素  

Investigation of the Performance of Organic Contaminant Degradation by Fe^(2+)/PDS Under Environmentally Relevant pH Conditions

作　　者：刘颖[1] 郭依玮 乔俊莲[1] 孙远奎 LIU Ying;GUO Yi-wei;QIAO Jun-lian;SUN Yuan-kui(College of Environmental Science and Engineering,Tongji University,Shanghai 200092,China;School of Ecological and Environmental Sciences,East China Normal University,Shanghai 200241,China)

机构地区：[1]同济大学环境科学与工程学院,上海200092 [2]华东师范大学生态与环境科学学院,上海200241

出　　处：《环境科学》2022年第8期4146-4153,共8页Environmental Science

基　　金：国家重点研发计划项目(2019YFC1805202);国家自然科学基金项目(22076143)。

摘　　要：利用Fe^(2+)活化过二硫酸盐(PDS)产生SO~-_(4)·等高活性氧化物种是去除有机污染物的重要方法.然而该方法通常只有在酸性条件下才能获得良好的污染物去除效果,限制了Fe^(2+)/PDS体系的实际应用.为此,分别从不同pH条件下Fe^(2+)活化PDS降解水中有机污染物的效能、活性氧化物的种类和氧气的影响等角度,系统分析了中碱性条件下Fe^(2+)/PDS体系难以氧化有机污染物的影响因素.结果发现,不同pH条件下Fe^(2+)/PDS体系中均有SO~-_(4)·和Fe(Ⅳ)的生成;中碱性条件下溶解氧可与PDS竞争Fe^(2+),但此时仍有可观的PDS(37.6%~100%)得到了活化且排除氧气并不能提高污染物的去除效果.通过改变Fe^(2+)的投量发现,过量的Fe^(2+)会显著降低Fe^(2+)/PDS体系对卡马西平的去除率,这表明过量的Fe^(2+)对活性氧化物种是无谓消耗,是导致中碱性条件下Fe^(2+)/PDS体系除污效能降低的重要原因.鉴于此,进一步探讨了零价铁或硫化零价铁替代Fe^(2+)活化PDS去除污染物的可行性,并利用同步辐射技术分析了零价铁的腐蚀情况.结果为中碱性条件下PDS的有效活化和实际应用提供了理论支撑.Peroxydisulfate(PDS) activation by Fe^(2+) has proven to be a promising method to abate emerging organic contaminants by generating reactive oxidation species.Nevertheless,this process may only achieve good decontamination performance under acidic conditions,which has markedly limited its application in real practice.To address this issue,we comprehensively investigated the performance of the Fe^(2+)/PDS process toward some probe contaminants at different pH levels and explored the potential change in reactive oxidative species and the influence of oxygen.Both SO^(-)_(4)· and Fe(Ⅳ) were identified to be involved in the Fe^(2+)/PDS process,and the types of these oxidative species did not change with varying pH values.Although dissolved oxygen could compete with PDS for Fe^(2+),especially at high pH values,this competition process was not the major reason for the declined performance of the Fe^(2+)/PDS process,since 37.6%-100% of PDS could also be activated with the presence of oxygen.Instead,the overdosing of Fe^(2+)could greatly inhibit carbamazepine removal,indicating that the nonproductive consumption of reactive oxidants by Fe^(2+)should account for the declined performance of Fe^(2+)/PDS under environmentally relevant pH conditions.Accordingly,the feasibility of applying zero-valent iron and sulfidated zero-valent iron was further evaluated,and the formation of corrosion products was characterized using X-ray absorption fine structure spectroscopy.All these findings will improve our understanding about the Fe^(2+)/PDS process and thus facilitate its application.

关 键 词：新型有机污染物 环境pH 过二硫酸盐 亚铁 零价铁 硫化 

分 类 号：X131[环境科学与工程—环境科学]