Equilibrium isotherm studies on the sorption of Pb(II) from solution by Ehandiagu clay

Abstract

The potential of Ehandiagu clay as an adsorbent for the removal of Pb(II) ions from aqueous solution was investigated. The purpose of this study is the application of the clay as a cheaper alternative for removal of Pb(II) from industrial waste waters. This would help reduce the challenge of the high cost involved in treating industrial effluents in Nigeria and most developing Nations. The effect of initial metal ion concentration was studied using batch method at an optimum pH of 5.0 and contact time of 2 hours. The result showed an increase in adsorption capacity with increase in initial metal ion concentration. In terms of percentage adsorbed, a decrease was observed with increasing metal ion concentration. The equilibrium isotherm regression parameter(R2) showed that the Langmuir isotherm (0.9787) gave a better fit than the Freundlich isotherm (0.9298), and the least been the Dubinin-Radushkevich isotherm (0.8001).The value of the apparent energy of adsorption (28.87J/mol) obtained from the Dubinin-Radushkevich isotherm indicates a physical adsorption process. The parameters obtained from the Langmuir and Freundlich isotherm showed that the sorption of Pb(II) ions on Ehandiagu clay is a favorable adsorption process. These results indicate the applicability of Ehandiagu clay as a good and cheap adsorbent for the removal of Pb(II) from aqueous effluents.