Indian Journal of Chemical Technology, Vol.22, No.3-4, 113-119, 2015
Adsorption of Indium(III) from aqueous solutions using SQD-85 resin
The feasibility of using SQD-85 resin as an adsorbent for indium(III) has been investigated. Various conditions such as solution pH, temperature and contact time on the adsorption of indium(III) has also been examined. The results show that the optimal adsorption condition of SQD-85 resin for indium(III) is achieved at the pH value of 5.5 in acetic acid-sodium acetate (HAc-NaAc) buffer solution. The maximum uptake capacity of indium(III) is 297.2 mg/g at 298K at an initial pH value of 5.5. The isotherms data fits well with Langmuir model better than Freundlich model. Kinetics on the adsorption of indium(III) has been studied. The apparent activation energy Ea and adsorption rate constant k(298) values are 12.11 kJ/mol and 5.07x10(-3) min(-1), respectively. The thermodynamic parameters with the Delta S value of 106.61 J/(K.mol) and Delta H value of 13.55 kJ/mol indicate that the adsorption process is endothermic in nature. While the decrease of Gibbs free energy (Delta G) with the temperature increasing indicates that the process occurred spontaneously. Finally, indium(III) can be eluted using 0.1 mol/L HCl solution and the elution percentage was relatively high (97%). Resins before and after indium(III) and adsorbed and characterized by IR spectroscopy and thermo-gravimetric analysis.