不同土地利用类型土壤对镉吸附特性研究

Cadmium Adsorption Characteristics of Different Land Use Types

以百色市江边土壤,草坪土壤和农作土壤这3种不同类型的土壤样品为供试对象,研究不同类型土壤对镉(Cd)的等温吸附特性。结果表明,土壤对镉的动力学吸附过程在0~6 h阶段为快速吸附阶段,6~28 h为慢吸附阶段,28~48 h为平衡阶段。等温吸附过程表明土壤随着加入溶液Cd浓度的增加,吸附量逐渐趋于饱和,吸附率逐渐下降。Langmuir方程能较好的描述土壤对镉的吸附过程,方程拟合得出3种土壤的最大吸附量(Q_(m))为2.27~2.66 mg/g,其中,农作土壤的最大吸附量(Q_(m))和最大缓冲容量(MBC)均最高,这可能与土壤的pH值和有机质含量大小有关。

Three different types of soil samples, namely, riverside soil, lawn soil and agricultural soil, were used as test subjects to study the isothermal sorption characteristics of cadmium by different types of soils. The results showed that the kinetic adsorption process of soil on Cd was fast at 0~6 h, slow at 6~28 h and saturated at 28~48 h. At different concentration gradients, the amount of soil adsorption of Cd was proportional to the added concentration and the adsorption rate was inversely proportional to the added concentration. The maximum adsorption of cadmium by soil was in the order of largest to smallest for agricultural soil >lawn soil > riverside soil. The greater the organic matter content or pH value in the soil, the greater the sorption capacity of the soil for cadmium.