研究了土壤中主要硅酸盐粘土矿物蒙脱石、伊利石、高岭石、海泡石对重金属镉的吸附行为.结果表明:硅酸盐粘土矿物吸附镉受酸度和离子强度的影响;吸附反应是快反应,能很好地符合Lagergren二级吸附速度方程;优化条件下的高岭石对镉吸附很弱,蒙脱石、伊利石、海泡石对镉的实验饱和吸附容量分别为2.88、1.08、2.82 mg/g,蒙脱石吸附镉更适合Freundlich拟合,伊利石、海泡石对镉的吸附结果更适合Langmuir拟合;相关性分析表明,硅酸盐粘土矿物对镉的饱和吸附容量大小与其理化性质有关,其中矿物中氧化锰含量高低与其对镉饱和吸附容量大小的相关性达到极显著水平.%An experimental study of the adsorption of clay minerals such as montmorillonite, illite, kaolinite and sepiolite for Ca~(2+) was conducted. The results indicate that acidity and ion intensity are factors affecting adsorption, that the adsorption reaction is rapid, and that adsorption kinetics is fitted well with the Lagergren quasi-second reaction rate model. Under the optional conditions, the adsorption of kaolinite for cadmium is weak, and the saturated adsorption capacities of montmorillonite, illite and sepiolite for cadmium are 2.88,1.08 and 2.82 mg/g respectively. The behaviors of adsorption of Cd~(2+) on montmorillonite are fitted to Freundlich Model, while the behaviors of adsorption of Cd~(2+) on illite and sepiolite are fitted to Langmuir Model. Correlation analysis shows that the saturated adsorption capacity of cadmium on silicate clay minerals is related to its physical and chemical properties, and the correlation between manganese oxides and the saturated adsorption capacity of cadmium is extremely significant.
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