摘要
pH值是影响污染土壤电动修复的主要因素。为此提出了交换电极法强化电动修复,并对该技术进行了实验研究。实验土壤Cr污染浓度为506.36 mg/kg,工作电压为1 V/cm,结果显示,固定电极方向运行模式下,运行2 d,产生聚焦效应,运行8 d,碱性区Cr(III)残留量和酸性区Cr(VI)残留量较大,分别是97.88 mg/kg和328 mg/kg,总铬去除率为59.04%。采用交换电极法,交换频率为4 d,运行8 d,总铬去除率为70.18%;交换频率为2 d,运行8 d,总铬去除率高达86.10%,土壤中总铬平均含量从506.36 mg/kg降至73.56 mg/kg,达到酸性土壤环境质量一级标准。该技术可控制土壤pH值在中性范围,电流密度高,不添加化学试剂,操作简单。
The successful electrokinetic treatment of heavy metal polluted soil depends mainly on soil pH value. Laboratory electrokinetic experiments were conducted using field soils with chromium concentration of 506.36 mg/kg, and subjected to a voltage gradient of 1 V/m. The results show that ＂focusing effect＂ generates in the second day using the conventional electrokinetie remediation with fixed polarity. The high remnant Cr（III） in alkaline zone and Cr（VI） in acid zone are observed, the concentration of which are 97.88 mg/kg and 328 mg/kg respectively. The low removal rate of 59.04% was achieved in 8 d. However, polarity exchange tech- nique removed 70. 18% Cr in 8 d when exchange frequency was 4 d. Another polarity exchange technique removed 86.10% Cr in 8 d when exchange frequency was 2 d, which decreased the initial concentration of total Cr from 506.36 to 73.56 mg/kg which met China Environmental Quality Standard I for Acid Soils. The polarity ex- change technique is easily automated without additional chemicals and complex equipments, and obtains high electric current intensity and neutral pH in soil.
出处
《环境工程学报》
CAS
CSCD
北大核心
2009年第2期354-358,共5页
Chinese Journal of Environmental Engineering
关键词
电动修复
交换电极法
铬污染土壤
聚焦效应
电流密度
electrokinetic remediation
polarity exchanges
chromium contaminated soil
focusing effect
electric current density
