pH值和流速对向海盐碱湿地土壤草根层吸附铅、 镉规律的影响

利用柱实验， 考察了向海盐碱湿地土壤草根层吸附Pb²⁺和Cd²⁺过程中的影响因素. 结果表明， 流速和pH值对动态吸附有很大影响， 流速加快， 穿透点提前， 穿透点吸附量减小； pH增加， 穿透点滞后， 穿透点吸附量增大； Pb²⁺与Cd²⁺在吸附过程中存在竞争吸附， Pb²⁺对Cd²⁺的吸附影响较大， 而Cd²⁺对Pb²⁺的吸附影响相对较小 . 不同pH值下， Pb²⁺和Cd²⁺的动态吸附过程均可用双常数速率方 程和Elovich方程描述， 且双常数速率方程更好.

Effects of pH and flow rate on the adsorption processes of Pb and Cd onto the soils sampled from the sod layers in Xianghai Wetland

The influences of flow rates and pH value on the adsorption of Pb and Cd by the sod layers from Xianghai Wetland were studied by the means of dynamic adsorption experiments. The results show that the penetrative point was advanced and the adsorbance at penetrative point was decreased with the increasing of the flow rates of the solution or the decreasing of pH value of the solution. When (Pb~(2+)) and (Cd~(2+)) coexisted with the initial equivalent concentration, their retention by soil was reduced compared to those when they existed individually, and the reduced percentage of (Cd~(2+)) was greater than that of (Pb~(2+)). The dynamic adsorption procedures of (Pb~(2+)) and (Cd~(2+)) on the soils can be described via double-constant rate (equation) and Elovich (equation) and described better by the former.