土壤中铜、铅离子的竞争吸附动力学

Competitive adsorption kinetics of copper and lead ions in soils

研究了Cu^2＋、Pb^2＋在2种土壤上的竞争吸附动力学过程．结果表明，Cu^2＋、Pb^2＋在乌栅土上的吸附量均高于在红壤上的吸附量，Pb^2＋又较Cu^2＋在土壤上的吸附量大．分别用一级、二级动力学方程、抛物线方程、Elovich方程和幂函数方程对该吸附动力学过程进行了拟合，其中幂函数方程拟合结果最好．Cu^2＋、Pb^2＋在乌栅土上的吸附主要是通过与土壤中的Ca^2＋、Mg^2＋进行交换，其累积吸附量与Ca^2＋、Mg^2＋的累积解吸量线性关系显著（R^2为0．990～1）；在红壤上是通过与土壤中的H^＋进行离子交换而吸附，Pb^2＋对Ca^2＋和Mg^2＋的交换能力比Cu^2＋强，其存在显著降低了Cu^2＋在2种土壤上的吸附量；Cu^2＋的存在略降低Pb^2＋在土壤上的吸附量。

Competitive adsorption kinetics process of Cu^2＋ and Pb^2＋ in two kinds of soil was studied. The adsorption quantities of Cu^2＋ and Pb^2＋ on Wushan soil were all higher than those of red soil. The adsorption quantity of Pb^2＋ was larger than that of Cu^2＋ in soil; these adsorption kinetic processes were fitted with the equations of first-order, second-order, parabola, Elovich and power function, respectively, in which the power function equation fitting results was the best, The adsorption of Cu^2＋ and Pb^2＋ on Wushan soil was mainly through exchange of Ca^2＋ and Mg^2＋ in soil, with marked linear relation between accumulative adsorption quantities and accumulated desorb-quantities of Ca^2＋ and Mg^2＋ （R^2 was 0.990-1）, the adsorption on red soil was through ion exchange of H^＋ in soil, The exchange capacity of Pb^2＋ on Ca^2＋ and Mg^2＋ was stronger than Cu^2＋, its existence lowered markedly the Cu^2＋ adsorption quantities on 2 kinds of soil; the existence of Cu^2＋ lowered a little the adsorption quantity of Pb^2＋ in soil.