Applications of Inorganic Ion Exchangers: II—Adsorption of Some Heavy Metal Ions from Their Aqueous Waste Solution Using Synthetic Iron(III) Titanate

Abstract

Adsorption of Zn²⁺ and Cd²⁺ ions from aqueous waste solutions on iron(III) titanate as inorganic ion exchange material was investigated to determine the effect of contact time, pH of solution and the reaction temperatures. Batch kinetic studies were carried out and showed that the time of equilibrium for both Zn²⁺ and Cd²⁺ ions was attained within three hours, and the order of kinetic reaction is the first order reaction. Batch distribution coefficients of Zn²⁺ and Cd²⁺ ions on iron(III) titanate as a function of pH have been studied at 25, 40 and 60 ± 1°C. From the obtained results we found that the K _d values decreased with increasing reaction temperatures. Enthalpy change (ΔH) values for Zn²⁺ and Cd²⁺ ions were found to be −8.19 and −22.49 kJ/mol, respectively. The data of adsorption of Zn²⁺ and Cd²⁺ ions at various concentrations were fitted with the Freundlich isotherm. Finally, separation of the above mentioned cations on iron(III) titanate in a column was performed.