难溶态Cr(Ⅵ)对重度铬污染土壤淋洗还原修复效果的影响  

EFFECT OF INSOLUBLE HEXAVALENT CHROMIUM ON REMEDIATION OF HEAVILY CHROMIUM-CONTAMINATED SOIL BY FLUSHING REDUCTION

作　　者：满益东 李东[1,2] 胡思扬[1,2] 霍金芬 MAN Yidong;LI Dong;HU Siyang;HUO Jinfen(College of Environment and Ecology of Chongqing University,Chongqing 400044,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学环境与生态学院,重庆400044 [2]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044

出　　处：《环境工程》2022年第7期132-138,164,共8页Environmental Engineering

摘　　要：通过对某铬渣堆场的重度铬污染土壤进行解吸动力学和难溶态Cr(Ⅵ)还原实验,揭示限制重度铬污染土壤有效修复的关键因素。结果表明:室温下,采用柠檬酸淋洗可显著降低土壤中难溶态Cr(Ⅵ)浓度,将淋洗温度提高至90℃,可进一步显著降低难溶态Cr(Ⅵ)浓度。淋洗后土样中难溶态Cr(Ⅵ)浓度越低,其还原效果越好。供试土样经柠檬酸高温淋洗+FeSO_(4)高温还原工艺修复后,Cr(Ⅵ)浓度从(1813.2±59.8)mg/kg降至(99.1±8.8)mg/kg。此外,淋洗实验中柠檬酸对难溶态Cr(Ⅵ)的还原可忽略不计;土样中残留的柠檬酸对土壤Cr(Ⅵ)的检测结果无显著影响。研究证明了难溶态Cr(Ⅵ)的还原效果是重度铬污染土壤修复的关键限制因素,结果可为铬污染土壤修复工艺研发提供参考。To reveal the key factors that limit the remediation effectiveness of heavily chromium contaminated soil,the desorption kinetics,and insoluble Cr(Ⅵ)reduction experiments were carried out in this study.The results showed that leaching with citric acid could significantly reduce the concentration of insoluble Cr(Ⅵ)in soil samples at room temperature,and increasing the leaching temperature to 90℃could further decrease the concentration of insoluble Cr(Ⅵ).The lower the concentration of insoluble Cr(Ⅵ)in the soil after leaching,the better the remediation effectiveness.For the soil samples used in this study,the concentration of Cr(Ⅵ)decreased from(1813.2±59.8)mg/kg to(99.1±8.8)mg/kg by hightemperature flushing with citric acid and high-temperature reduction with ferrous sulfate.In addition,the reduction of insoluble Cr(Ⅵ)by citric acid in the leaching experiment could be ignored and the residual citric acid in the soil sample had no significant effect on the detection results of Cr(Ⅵ)in soil.This study proved that the reduction effectiveness of insoluble Cr(Ⅵ)was the key limiting factor for the remediation of heavy chromium-contaminated soil,and provided a reference for the research and development of remediation technology for chromium contaminated soil.

关 键 词：铬污染土壤 难溶态Cr(Ⅵ) 柠檬酸 淋洗 还原 

分 类 号：X53[环境科学与工程—环境工程]