巯基坡缕石-硫酸锰复配对碱性土壤镉污染钝化阻控效应

为探讨巯基坡缕石（MPAL）和硫酸锰（MnSO₄）复配处理对碱性土壤镉（Cd）污染钝化阻控效应，以河南省Cd污染小麦土作为供试土壤，进行了土壤单施MPAL、单施MnSO₄及MPAL和MnSO₄复配施用的为期30 d的土壤老化培养实验。结果表明：土壤孔隙水中Mn含量主要受外源MnSO₄添加剂量的影响，受MPAL添加量影响较小。随着外源MnSO₄添加剂量的增加，土壤DTPA-Mn含量显著升高，但DTPA-Cd含量与空白对照（不添加MPAL和MnSO₄）间并无显著差异。MnSO₄和MPAL复配施用对碱性土壤Cd的钝化效果优于单施MPAL和单施MnSO₄处理，其中，MPAL和MnSO₄复配处理、单施MnSO₄及单施MPAL处理对土壤Cd的最大钝化率分别为57.7%、19.2%和41.8%。在所有复配处理中，添加0.025% MnSO₄对MPAL钝化Cd无显著影响或存在一定的活化作用，而添加0.1%~0.2% MnSO₄对MPAL钝化Cd具有促进作用，在较高剂量MnSO₄对MPAL钝化Cd呈促进作用的情况下，MnSO₄对0.01% MPAL作用最大，随着MPAL添加剂量的增加，这种促进效应逐渐降低。研究表明，MPAL与MnSO₄合适剂量复配处理可以高效固定土壤Cd，是适用于修复碱性农田Cd污染土壤的良好方法。

Immobilization effect of mercaptopalygorskite and manganese sulfate on Cd pollution in alkaline soil

To investigate the inhibition effect of mercaptoplagnite(MPAL) and manganese sulfate(MnSO₄) on the immobilization of alkaline soil cadmium(Cd) pollution, Cd contaminated wheat soil in Henan Province was collected as the test soil. Soil aging was conducted for 30 days by applying MPAL, MnSO₄, and both MPAL and MnSO₄. The results showed that the Mn content in soil pore water was mainly affected by the supplemental dose of exogenous MnSO₄, and less affected by the amount of MPAL. With an increase in the exogenous MnSO₄ supplemental dose, the soil DTPA-Mn content increased significantly; however, there was no significant difference in DTPA-Cd content compared with the control treatment. The combined application of MnSO₄ and MPAL on the immobilization effect of Cd in weakly alkaline soil was better than that observed after individually applying MPAL and MnSO₄. The maximum passivation rates of soil Cd after treating with the combination of MPAL and MnSO₄, MnSO₄, and MPAL were 57.7%, 19.2% and 41.8%, respectively. In all the distribution processing protocols and combination treatments, the addition of 0.025% MnSO₄ either had no significant effect on MPALpassivated Cd or tended to activate it slightly, while the addition of 0.1%~0.2% MnSO₄ had a promoting effect on MPAL-passivated Cd.During the promotion effect of a high MnSO₄ dose on MPAL-passivated Cd, MnSO₄ had the greatest effect on 0.01% MPAL, and the promotion effect gradually decreased with an increase in the MPAL dose. The combined treatment of MPAL and MnSO₄ with appropriate dose could efficiently fix Cd in soil and was a good method suitable for the remediation of Cd-contaminated soil in alkaline farmland.