Platinum(IV) Chloride Complex Ions Adsorption on Activated Carbon Organosorb 10CO

Abstract

Kinetic studies on the recovery of platinum(iv) chloride complex ions from acidic solutions using commercially available activated carbon (AC) were carried out using spectrophotometric methods. The overall process obeyed first-order reaction model. The overall process is complex and consists of two steps: the first one is related to the reversible adsorption–desorption of PtIV complex and the second one is related to the reduction of PtIV complex on the AC surface. The first step of the overall process was limited by diffusion, whereas the second step ran under kinetic control. The activation energies of the individual reactions in both steps were determined and corresponded to 18.27, 7.85, and 31.2 kJ mol–1 for the adsorption, desorption, and reduction reactions, respectively. X-ray photoelectron spectroscopy results confirmed that the chemical reaction was related to the reduction of PtIV to PtII on the AC surface. The results show that the investigated AC can be applied for platinum recovery from highly diluted aqueous systems.