【摘要】 本文研究了胡敏素和磷酸二氢钾（KH₂PO₄）单独施用以及胡敏素和KH₂PO₄联用等不同情况下,污染土壤中重金属Cu形态的动态变化;采用TCLP（Toxic characteristic leaching procedure）法评价了不同配比钝化剂对污染土壤中Cu的钝化作用,以土壤中典型的根系分泌物酒石酸作为重金属解吸剂来模拟研究土壤中小分子有机酸对Cu钝化后的产物形态变化的影响.结果表明,土壤添加胡敏素和KH₂PO₄能够不同程度地升高土壤pH值,二者联用使酸性土壤pH值从4.90升高到5.22—5.30;添加不同比例的胡敏素和KH₂PO₄均降低了土壤TCLP提取态和酸提取态Cu含量,且P/Cu摩尔比为4∶1时,土壤TCLP提取态和酸提取态Cu含量分别降低了67.8 mg·kg^-1和104.5 mg·kg^-1,而残渣态的Cu含量增加了17.3 mg·kg^-1.胡敏素和KH₂PO₄联用的效果显著优于二者单独使用;土壤溶液中存在的根系分泌物成分酒石酸对土壤中的Cu具有解吸作用,解吸率随酒石酸浓度增加而提高.胡敏素和KH₂PO₄的联用减少了Cu的解吸,降低了Cu的迁移性.更多还原

【Abstract】 This study investigated the dynamic change of Cu in contaminated soil under different conditions, including the presence of sole humin and sole potassium dihydrogen phosphate（KH₂PO₄）, as well as the presence of humin combined with KH₂PO₄, respectively. The effect of humin and phosphate under different ratios on the passivation of Cu in contaminated soil was evaluated through the toxic characteristic leaching procedure（TCLP）. Tartaric acid of typical root exudates in soil was used as a desorbent to stimulate the effect of low molecular weight organic acids on the stability of passivation products. The results indicated that the addition of humin and KH₂PO₄ increased soil pH, e.g, the addition of humin in combination with phosphate enhanced soil pH from 4.90 to 5.22— 5.30. The addition of humin and KH₂PO₄ under different ratios significantly reduced the content of TCLP and acid extraction of Cu from soil. When the P/Cu molar ratio was 4:1, the soil TCLP extraction state and acid extraction Cu content decreased by 67.8 mg·kg^-1 and 104.5 mg·kg^-1, respectively, while the residual Cu content increased by 17.3 mg·kg^-1. The passivation effect on Cu of humin in combination with KH₂PO₄ was better than sole humin or KH₂PO₄. Tartaric acid as a root exudate widely presented in the soil solution, had desorption effect on the passivated Cu in soils, and the desorption increased as the concentration of tartaric acid was increased. In summary, the combination of humin and KH₂PO₄ reduced Cu desorption and hence decreased its migration in soil.更多还原