Equilibrium, Thermodynamic, and Kinetic Studies for the Adsorption of Cadmium(II) Ions onto Activated Carbon Prepared from Euphorbia rigida by Chemical Activation

Abstract

Equilibrium, thermodynamic, and kinetic studies were carried out for the adsorption of cadmium(II) ions from aqueous solution using high surface area (2,613 m(2)/g) microporous activated carbon prepared from Euphorbia rigida by chemical activation. Optimum adsorption conditions were determined as a function of pH, adsorbent dosage, initial metal ion concentration, contact time, and temperature of solution. Adsorption data were well described by the Langmuir isotherm model. The adsorption process obeys the pseudo-second order kinetic model. The thermodynamic parameters Delta G degrees, Delta H degrees, and Delta S degrees showed feasible, chemical, spontaneous, and endothermic adsorption.