铜(Ⅱ)在高岭石表面的吸附

ADSORPTION OF COPPER(Ⅱ) ON KAOLINITE

在天然水体系中 ,铜、铅、镉等重金属元素的形态分布、迁移、归宿和生物有效性强烈取决于重金属元素在水体颗粒物表面的分配趋势。本文对铜 ( )在常见的重要粘土矿物——高岭石表面的吸附进行了实验和模式研究 ,结果表明 ,在同时考虑自由水合离子 Cu2 +和羟基金属离子 Cu OH+与高岭石表面络合的情况下 ,单一表面基团、无静电表面络合模式能很好地描述铜 ( )的吸附行为。拟合得到的 Cu OH+ 的络合常数比 Cu2 + 的大得多。铜 ( )在高岭石表面的吸附量随 p H值的升高而增加。吸附铜的两种表面化合态 ,>SOCu+和 >SOCu OH的浓度在实验的 p H范围内 ,也随 p H值升高而增加 ,并且以>SOCu+

For natural aquatic systems, the distribution of shape, transport, fate and bioavailability of heavy metals such as copper, lead and cadmium strongly depend on the distribution tendency of metals on to particulate surfaces. In this paper, an experimental and modeling study of copper(Ⅱ) adsorption on kaolinite, a common and important clay mineral, was conducted. The results showed that the single-site nonelectrostatic model was capable of describing the adsorption behavior of copper(Ⅱ) when both of the surface complexation reactions of free aquo ion Cu 2+ and monohydroxy complex CuOH + to kaolinite surface were included in the analysis. Fitted surface complexation constant for CuOH + was much greater than that for Cu 2+ . The adsorption amount of copper(Ⅱ) on kaolinite increased with a rise of pH.In the experiment pH range,the concentration of two kinds of adsorption species of copper(Ⅱ),>SOCu + and >SOCuOH,also increased with the rise of pH and the >SOCu + is predominant.