Abstract: 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 Pb²⁺ and Cd²⁺ coexisted with the initial equivalent concen tration, their retention by soil was reduced compared to those when they existed individually, and the reduced percentage of Cd²⁺ was greater than that of Pb²⁺. The dynamic adsorption procedures of Pb²⁺ and Cd²⁺ on the soils can be described via double-constant rate equation and Elovich equation and described better by t he former.

Key words: sod layer soil, pH value, flow rate, lead, cadmium, adsorption