基于多点位分析的铬污染土壤电动修复

Electrokinetic Remediation of Chromium Contaminated Soil Based on Multi-site Analysis

采用电动修复法对铬含量为600 mg/kg的污染土壤进行了处理。基于多点位分析研究了修复时间和修复电压对铬迁移、价态转化和形态转化的影响规律。结果表明:随着修复电压和修复时间的增加,铬的迁移率提高;当修复电压为30 V,修复时间为14 d时,土壤中的Cr(T)含量下降至200 mg/kg以下,低于中国土壤环境质量标准(GB 15618—1995)中二级农业用地的限值;修复完成后,土壤中大部分的Cr(Ⅵ)转化为Cr(Ⅲ),可交换态、碳酸盐结合态、铁锰氧化物结合态等不稳定态向有机物结合态及残渣态等稳定态转化,铬的环境风险(物理流动性和生态风险)降低。

The contaminated soil with chromium content of600mg/kg was treated by electrokinetic remediation.The effects of repair time and repair voltage on chromium migration,valence changes and morphological transformation were studied based on multi-point analysis.The results showed that the mobility of chromium improved as the repair voltage and repair time increased.And the chromium content in the soil can be reduced to below200mg/kg with repair voltage of30V and repair time of14d which can meet the limit value of secondary agricultural land in China environmental quality standard for soils(GB15618-1995).After the repair,most of the Cr(Ⅵ)in the soil was transformed into Cr(Ⅲ),and the unstable chromium including exchangeable,carbonate-bound,and iron-manganese oxide bound was transformed into stable chromium including organic matter bound and residualstate,which indicates the environment risk(low physicalmobility and low eco-risk)was reduced.