Assessment of the adsorption of thorium onto styrene-divinylbenzene-based resin: Optimization using central composite design and thermodynamic parameters

Adsorption of thorium on styrene-divinylbenzene-based resin was investigated to obtain the optimum adsorption conditions by using the central composite design (CCD) method. This study was performed in 30 runs of experiments as a function of pH, thorium concentration, contact time and temperature. Adsorption performance of styrene-divinylbenzene-based resin was higher than 98%. The optimum adsorption of thorium using styrene-divinylbenzene-based resin can be successfully predicted statistically by the CCD method. In addition, sorption isotherm models such as Langmuir, Freundlich and Dubinin-Radushkevich were applied, and adsorption of Th(IV) was described most precisely by the Langmuir isotherm, which has the highest R2 (0.99) value. Thermodynamic parameters showed that the adsorption is an exothermic and spontaneous physical process. The results of this study reveal that this type of synthetic resin can be used as an effective sorbent material for the removal of Th(IV) ions from weakly aqueous solutions in remediation and nuclear wastewater treatment.