天然水体沉积物对重金属离子的吸附特性

ADSORPTION BEHAVIORS OF THE NATURAL SEDIMENT ON HEAVY METALS

本文运用表面络合模式,研究了江西乐安江下游黄龙庙沉积物的吸附特性,测定了样品对重金属CU(Ⅱ),Cd(Ⅱ)的吸附等温线和pH吸附突跃曲线;应用FITEQL程序计算了沉积物的表面固有吸附常数;对恒定容量模式、扩散层模式和三层模式在天然水体沉积物中的应用进行了比较.结果表明,应用表面络合模式研究天然水体沉积物的吸附特性是可行的,三种模式对重金属CU(Ⅱ),Cd(Ⅱ)在沉积物表面的吸附行为都有较好的预测性;有机物是影响金属离子吸附的一个重要因素.

In this paper, the surface complexation models were used to study the adsorption characteristics of Huanglong miao sediment in the downstream of Lean river in Jiangxi province. The adsorption isotherms and the pH adsorption edges of heavy metals C'u ( Ⅱ ) , Cd ( Ⅱ ) were measured. The intrinsic surface adsorption constants of the sediment were calculated via FITEQL computer program. The applications of the three surface complexation models, which are the Constant Capacitance Model, the Diffuse Layer Model and the Triple Layer Model, to the natural sediment were compared. The results demonstrate that it is possible to apply the surface complexation models to study the adsorption properties of the natural sediment. All the three models can give good descriptions and predictions to the behaviors of heavy metals Cu ( Ⅱ ), Cd ( Ⅱ ) on the sediment. Organic material is an important influential factor for the uptake of heavy metal ions.