Simulation of lead ions adsorption onto the iron-coated medium: Dependent on temperature and pH

Heat was employed to coat crystalline goethite onto a quartz sand surface so that the adsorbent properties of the coating could be utilized. Adsorption experiments were conducted to further demonstrate the adsorption of lead ions by goethite-coated medium under various temperatures and pH, respectively. The adsorption reaction between iron-coated medium and lead ions was simulated by a cation exchange model. Results indicated that the solution temperature and pH had a noticeable effect on the final adsorption capacity for lead ions. The pH-adsorption edges were shifted to lower pH values with increasing temperature. The adsorption reaction between lead ions and goethite-coated medium was an endothermic process. A cation exchange model applied to the regression model of experimental data was fitted very well. A high correlation coefficient (r2=0.91) and an extreme low p-value (7.02 × 10-82) indicated that the variance of dependent variable, adsorption capacity of iron-coated medium could be firmly explained by independent variables such as [Pb+n], temperature and [H+]. © 2006 ASCE.