土壤中铜、铅离子的竞争吸附动力学

研究了Cu²⁺、Pb²⁺在2种土壤上的竞争吸附动力学过程.结果表明,Cu²⁺、Pb²⁺在乌栅土上的吸附量均高于在红壤上的吸附量,Pb²⁺又较Cu²⁺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.Cu²⁺、Pb²⁺在乌栅土上的吸附主要是通过与土壤中的Ca²⁺、Mg²⁺进行交换,其累积吸附量与Ca²⁺、Mg²⁺的累积解吸量线性关系显著(R2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.Pb²⁺对Ca²⁺和Mg²⁺的交换能力比Cu²⁺强,其存在显著降低了Cu²⁺在2种土壤上的吸附量;Cu²⁺的存在略降低Pb²⁺在土壤上的吸附量.

Competitive adsorption kinetics of copper and lead ions in soils

Competitive adsorption kinetics process of Cu2+ and Pb2+ in two kinds of soil was studied. The adsorption quantities of Cu2+ and Pb2+ on Wushan soil were all higher than those of red soil. The adsorption quantity of Pb2+ was larger than that of Cu2+ 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 Cu2+ and Pb2+ on Wushan soil was mainly through exchange of Ca2+ and Mg2+ in soil, with marked linear relation between accumulative adsorption quantities and accumulated desorb-quantities of Ca2+ and Mg2+ (R2 was 0.990~1), the adsorption on red soil was through ion exchange of H+ in soil. The exchange capacity of Pb2+ on Ca2+ and Mg2+ was stronger than Cu2+, its existence lowered markedly the Cu2+ adsorption quantities on 2 kinds of soil; the existence of Cu2+ lowered a little the adsorption quantity of Pb2+ in soil.