Adsorptive removal of cadmium from aqueous solution by cork biomass: Equilibrium, dynamic and thermodynamic studies

The removal of toxic metal, cadmium, by using adsorption into Algerian cork biomass was investigated. The biosorption process was studied with respect to contact time, particle size, pH and temperature. The results showed that equilibrium was reached within 1 h. The used biosorbent gave the highest adsorption capacity at pH 6. The experimental isotherm data were analyzed and modeled. The maximum adsorption capacity, Langmuir's qmax, improved from 9.65 to 14.77 mg/g as the temperature increased from 20 to 40 °C. The enthalpy ΔH° and entropy ΔS° values were respectively estimated at 110.47 kJ mol−1 and 0.3795 kJ K−1 mol−1 for the process, which reflects the endothermic nature and the spontaneous feasibility of the present sorption system. Besides, the adsorption kinetics was found to follow the second-order model, suggesting therefore a possible chemisorption process.