外源重金属离子在黄河沉积物中的竞争吸附

Competitive Adsorption on Exotic Heavy Metals Ions in Sediments of the Yellow River

以黄河包头段上游清洁河段的沉积物为吸附剂,采用吸附竞争系数对Pb2+、Cu2+、Zn2+、Cd2+等4种外源重金属离子在黄河沉积物中的竞争吸附进行了探讨。结果表明,当外源重金属离子浓度或体系的离子强度增加时,Pb2+、Cu2+的吸附竞争系数增大,Zn2+、Cd2+的吸附竞争系数减小;不同离子间的竞争吸附有显著的拮抗或协同效应,且此效应的显著程度随体系中离子总量的增加而减弱;黄河沉积物对4种重金属离子的吸附能力排序为:Pb2+≥Cu2+>Zn2+≈Cd2+;温度对外源重金属离子间竞争吸附的影响较为复杂。

The competitive adsorption of a sediment sample on heavy metals ions were studied by using adsorption competitive coefficients as a method in this paper. The sediment sample in clean reach from Baotou Section of the Yellow River was taken to tailor a system for the adsorbent and composite of Pb2+ , Cu2+ , Zn2+ and Cd2+ as the adsorbates. The result showed: the adsorption competitive coefficients of Pb2+ and Cu2+ increased and that of Zn2+ and Cd2+ decreased with the increase of the exotic heavy metals ionic concentrations and the ionic strength, while the marked resistance or cooperation adsorption relation existed between the different ions, which decreased with the increase of the total ionic concentrations. The capacity of competitive adsorption of four heavy metals ions was in an order: Pb2+ ≥ Cu2+ > Zn2+ ≈ Cd2+ in the sediment of the Yellow River. In addition, the effect of temperature on competitive adsorption was found to be complicated.