紫色土中Cu^(2+)、Zn^(2+)吸附特征研究

Research on the Adsorption Characteristics of Purple Soil to Heavy Metal

[目的]了解紫色土对铜、锌的吸附特点。[方法]采用振荡平衡的方法研究了铜、锌在酸性、中性和石灰性3种紫色土中的吸附特征,并同时比较了不同环境条件对2种离子在3种紫色土中的吸附影响。[结果]研究得出,一定pH值条件下,在同种土壤上的吸附能力大小依次是Cu2+>Zn2+;3种紫色土在一定pH值条件下对同种重金属离子的吸附强度依次是石灰性紫色土>中性紫色土>酸性紫色土,与其表面电荷密度的大小相一致;Cu2+在3种紫色土表面以电性吸附和专性吸附的方式共存,其专性吸附的比例分别约为石灰性紫色土40%、中性紫色土25%、酸性紫色土20%;而Zn2+在土壤表面上绝大多数发生电性吸附。[结论]这2种重金属在紫色土中的吸附特征对库区土壤重金属污染评价有重要意义。

[Objective] The adsorption characteristics of purple soil to heavy metals（including Cu2＋,Zn2＋） was understood through the experiment.[Method]The adsorption behavior of the acidic,neutral and calcareous purplish soils to heavy metal under the different conditions was studied with batch sorption method,and also,the effect of three types of soils on adsorption of Cu2＋ and Zn2＋ was compared.[Results]The experimental results showed that： at certain pH,the adsorption strength of same soil to heavy metal was Cu2＋〉 Zn2＋;at certain pH,the quantity of same heavy metal adsorbed by soil was calcareous purplish soils〉 neutral〉 acidic,which was in line with the surface charge density;and Cu2＋ adsorption in three types of soils,which included electrical adsorption as well as specific adsorption,accounted for about 40%,25% and 20%,respectively.However,Zn2＋adsorption,belonged to electrical adsorption.[Conclusion] It was important significant to understand the adsorption characteristics of Cu2＋ and Zn2＋ for the evaluation of the heavy metal pollution in the soil of reservoir area.