酸活化坡缕石对土壤中Cd的钝化效果研究

为探究不同浓度H_2SO_4溶液活化的坡缕石对土壤中Cd的钝化效果,使用浓度分别为5%、7.5%、10%、12.5%、15%的H_2SO_4溶液对坡缕石进行活化,加入Cd污染土壤进行钝化实验和盆栽实验。结果表明:施加不同浓度H_2SO_4溶液活化的坡缕石均能显著降低土壤有效态Cd含量,10%的H_2SO_4活化的坡缕石钝化效果最显著,毒性浸出(TCLP)和二乙烯三胺五乙酸(DTPA)提取态Cd含量分别降低31.11%和37.33%。通过欧洲共同体参考机构(BCR)连续提取法测定结果表明酸活化坡缕石能显著降低土壤中Cd的酸溶态含量和还原态含量,酸活化坡缕石能显著抑制玉米对土壤中Cd的吸收和地下部分向地上部分的转移,使玉米地上部分Cd的含量相比对照组降低26.99%～43.97%,玉米地下部分Cd的含量相比对照组降低15.36%～27.40%。酸活化坡缕石对土壤中的Cd有明显的钝化效果。

The effect of palygorskite modified by acid on stabilization of Cd in soil

To explore the stabilization effect of palygorskite activated by different concentrations of H₂SO₄ solution on Cd in soil, the authors carried out acid activation of palygorskite by using H₂SO₄ solutions with concentrations of 5%, 7.5%, 10%, 12.5% and 15%, respectively. Stabilization experiments and pot experiments were carried out with the addition of Cd contaminated soil. The results showed that the active Cd content of soil was significantly reduced by applying palygorskite activated by different concentrations of H₂SO₄ solution, and that the stabilization effect of 10% H₂SO₄ activated palygorskite was the most significant. The extracted Cd content of toxic leaching (TCLP) and diethylene triamine pentacetic acid (DTPA) decreased by 31.11% and 37.33%, respectively. The results of continuous extraction by the European Community Reference Agency (BCR) showed that palygorskite modified by acid can significantly reduce the content of acid-soluble state and reduction state of Cd in soil. The palygorskite modified by acid could significantly inhibit the absorption of Cd in soil and the transfer of underground part to the aboveground part. The content of Cd in the surface part of maize decreased by 26.99%~43.97% compared with the control group, and the content of Cd in the underground part of maize decreased by 15.36%~27.40% compared with the control group. Palygorskite modified by acid has obvious stabilization effect on Cd in soil.