POTENTIAL OF PUMICE MODIFIED WITH IRON(III) FOR COPPER REMOVAL FROM AQUEOUS SOLUTIONS

Abstract

Iron-modified pumice (Fe-P) was prepared by the ion-exchange method using natural pumice from Kayseri, Turkey at room temperature without calcination. SEM, FTIR, XRD, and S-BET measurement were used to investigate the copper removal mechanism. The results show that the SBET of the pumice increased from 11.88 m(2)/g to 21.01 m(2)/g after iron modification. The effects of pH, contact time, initial copper concentration, temperature, and various cations (Na+, K+, Ca2+, Mg2+ and Al3+) at various pH were investigated in batch experiments. More than 92% of Cu(II) was removed after 180 min. Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models were applied to the equilibrium data at 298, 308 and 318 K. The maximum adsorption capacity at 298, 308 and 318 K was found to be 21.52, 19.48, and 19.67 mg/g, respectively. The kinetics of copper on Fe-P was best described by the pseudo-second order kinetic model. The negative values of free energy change and enthalpy change indicated that the adsorption process was feasible, spontaneous and exothermic.