Ash for the treatment of cd(Ii) rich effluents

Abstract

The removal of Cd(II) by adsorption on fly ash has been found to be contact time, concentration, temperature and pH dependent. The process of removal follows first order adsoiption kinetics and the rate controlling step is intraparticle transport into the pores of fly ash particles. The equilibrium nature of Cd(II) adsorption at different temperatures has been described by the Langmuir isotherm. The temperature dependence of Cd(II) adsorption on fly ash indicates the exothermic nature of adsoiption. Alkaline aqueous medium favours the removal of Cd(II) by fly ash. The increase in adsorption of Cd(II) vith pH has been explained on the basis of surface complex formation approach. Key words: adsorption, fly ash, contact time, concentration, temperature, pH, intraparticle transport, Langmuir isotherm, exothermic, surface complex. © 1987 Taylor & Francis Group, LLC.