用纯水提取-草酸冷冻还原法修复Cr(Ⅵ)污染土壤  

Remediation of Cr(Ⅵ)-Contaminated Soil by Pure Water Extraction Combined with Oxalic Acid Freezing Reduction Method

作　　者：孟美真 王楠 秦雨菲 于舒弋 康春莉 MENG Meizhen;WANG Nan;QIN Yufei;YU Shuyi;KANG Chunli(College of New Energy and Environment,Jilin University,Changchun 130012,China;Ecological Environment Monitoring and Scientific Research Center of Songliao Basin Ecological Environment Supervision Administration,Ministry of Ecology and Environment,Changchun 130102,China)

机构地区：[1]吉林大学新能源与环境学院,长春130012 [2]生态环境部松辽流域生态环境监督管理局,生态环境监测与科学研究中心,长春130102

出　　处：《吉林大学学报（理学版）》2024年第2期464-472,共9页Journal of Jilin University:Science Edition

基　　金：国家自然科学基金(批准号:41977314)。

摘　　要：通过实验室模拟研究将纯水提取与冷冻法相结合修复Cr(Ⅵ)污染土壤的可行性.结果表明,对于1000 mg/kg Cr(Ⅵ)污染土壤,利用纯水进行提取,总铬的提取率约为35%,该结果与常规的草酸提取法相近.向纯水提取液中加入草酸,使其浓度为500μmol/L,冷冻结冰后,提取液中Cr(Ⅵ)的还原率达97%.NaCl,NaNO_(3),Na_(2)SO_(4)对Cr(Ⅵ)的去除效果有微弱的抑制作用.紫外吸收光谱、X射线光电子能谱、红外光谱和三维荧光光谱测试结果表明,该方法的作用原理为草酸提供H+,土壤中的溶解性有机质(DOM)作为还原剂,通过冷冻浓缩效应使土壤提取液中六价铬被还原.可见,纯水提取与草酸冷冻法相结合可用于异位修复Cr(Ⅵ)污染土壤,并可减少化学试剂的用量,有利于维护土壤理化性质的稳定.The feasibility of remediation of Cr(Ⅵ)-contaminated soil by combining pure water extraction and freezing method was studied through laboratory simulation.The results show that for 1000 mg/kg Cr(Ⅵ)-contaminated soil,the extraction rate of total chromium is about 35%by using pure water for extraction,which is similar to the conventional oxalic acid extraction method.After freezing and icing,oxalic acid was added to the pure water,extraction solution at a 500μmol/L,the reduction rate of Cr(Ⅵ)in the extraction solution reaches 97%.NaCl,NaNO_(3),and Na_(2)SO_(4)have a weak inhibitory effect on removal efficiency of Cr(Ⅵ).The ultraviolet absorption spectrum,X-ray photoelectron spectroscopy,infrared spectra,and 3D fluorescence spectroscopy tests show that the working principle of the method is that oxalic acid provides H+,and dissolved organic matter(DOM)in the soil acts as a reducing agent,hexavalent chromium in the soil extract is reduced through the freeze-concentration effect.Therefore,the combination of pure water extraction and oxalic acid freezing method can be used for the ex-situ remediation of Cr(Ⅵ)-contaminated soil,and can decrease the usage of chemical reagents,which is conducive to maintaining the stability of soil physicochemical properties.

关 键 词：铬 土壤 纯水提取 草酸还原 冷冻 异位修复 

分 类 号：X131[环境科学与工程—环境科学]