The main mechanisms involved in Cd transport in satruated subsurface soil was studied by modelling it as a fixed bed adsorption system. Experiments conducted with ditterent particle sizes of sand (and at pH 6.0) indicated that isotherm parameters depend on sand particle size. Freundlich isotherm gave better correlation for adsorption of Cd in sand medium than Langmuir isotherm. The applicability of relative solute velocity transport model derived from general solute transport equation, incorporating Freundlich isotherm (with local equilibrium assumption) was investigated. The relative solute velocity predicted from batch experimental data was higher than that of soil column breakthrough data, thus isotherm parameters estimated from the column breakthrough were used in model simulation. The relative Cd velocities (to Darcy's velocity)were found to be in the range of 0.0008 to 0.001., indicating limited mobility under the conditions tested.
嘉南學報 17期 : p.A60-A68 轉載 International Conf. On Computer Application in Water Resources, 2 p. 969-977