络合剂和酸度控制对土壤铬电动过程的影响

Influence of complexes and acidity control on electrokinetic processes of soil chromium

研究了添加络合剂和控制阴极池溶液酸度对铬在黄棕壤中电动过程的影响.结果表明,EDTA 柠檬酸和乳酸的加入明显改变了电动过程中电渗流的大小和铬在土柱中的分配,其中柠檬酸因可与土壤中的 Cr(III)发生较强的络合作用而显著增加了土壤总铬的去除率(29.8%);改变阴极池溶液酸度不仅影响了电动过程中电流、电渗流的大小和铬在土柱中的分配,同时也显著改变了总铬的去除率.其中在 pH 6.0 和pH 10.0 时,总铬的去除率分别达 25.3%和 24.0%,较 pH 4.0 和 pH 8.0 时增高近 1 倍.所有电动处理以后土壤中剩余的六价铬浓度均显著减少,约降低 80%,表明电动处理对土壤中六价铬(铬的主要有毒形态)的去除是非常有效的.

The influence of adding complex and controlling the acidity of cathode pond solution on Cr electrokinetic processes in a yellow brown soil was inspected. The addition of EDTA, citric acid and lactic acid changed markedly the quantity of electroosmotic flow and Cr distribution in soil column in the electrokinetic process, in which citric acid increased markedly the removal rate of total Cr in soil (29.8%), due to stronger complexation action of citric acid with Cr(III) in soil. The change of the acidity of cathode pond solution not only affected the electric current, quantity of electroosmotic flow and Cr distribution in soil column in the electrokinetic process, but also changed markedly the removal rate of total Cr, in which at pH 6.0 and 10.0, the rates was 25.3% and 24.0% respectively, nearly one time higher those at pH 4.0 and 8.0. The concentrations of all residual six valence Cr in soil decreased markedly about 80% after electrokinetic treatment, showing the very effective removal of six valence Cr (the main toxic form of Cr) in soil by the treatment.