高浓度铬污染土壤水浸泡与电动修复联合处理实验

对含铬量为2 142 mg/kg的铬污染土壤首先使用蒸馏水进行6轮浸泡试验,然后再进行电动修试验。土壤经过浸泡、通电24 h和72 h处理后总铬的去除率分别为:47%、61%和70%,表明预浸泡可以显著降低电动修复的负荷从而降低整个土壤修复费用。电动修复过程中对土壤两端的温度进行了测量以间接反映土壤电阻的分布和变化情况。结果显示土壤电阻逐渐上升,从阴极端开始逐渐过渡到阳极端,60 h之后达到最高值并保持稳定。电动修复的电流效率随土壤中铬浓度的降低而下降。此外,浸泡和电动修复均导致整个土壤和各断面铬浓度分布不均匀性增大。

Water dipping and electrokinetic jointed remediation of a heavily chromium-contaminated soil

A heavily chromium-contaminated soil with total chromium (TCr) concentration of 2 142 mg/kg was dipped in distilled water six times before electrokinetic remediation (EKR). The TCr removal rates of 47%, 61% and 70% were respectively achieved after water-dipping, 24 h EKR and 72 h EKR in order, demonstrating that pre-dipping treatment was able to significantly reduce the load of EKR and consequently save the overall remediation cost. During EKR temperatures at two ends of soil were monitored to indirectly depict the soil resistance distribution and change. The results show that the soil resistance was gradually increasing from the cathode end to the anode end and leveled off after 60 hours. The current efficiency of EKR was decreasing with the decrease of TCr concentration. In addition, both water-dipping and EKR can increase the differentiation of TCr concentration distribution across monitoring sections and the whole soil.