Fibrous polyethylenimine/polyvinyl chloride crosslinked adsorbent for the recovery of Pt(IV) from acidic solution: Adsorption, desorption and reuse performances

This study focused on evaluating the characteristics and performance of polyethylenimine (PEI)/polyvinyl chloride (PVC)-crosslinked fiber (PEI/PVC-CF) as an adsorbent for Pt(IV) sorption. To fabricate the PEI/PVC-CF, a PEI/PVC crosslinked polymer mixture was synthesized through the alkylation reaction at 80 degrees C for 6 h and then this polymer mixture was extruded into fibers in water. The analyses of SEM and FTIR were performed to identify the adsorptive characteristics of the PEI/PVC-CF and the binding mechanism between the Pt(IV) and adsorbent. The valuable sorption performance of Pt(IV) by the PEI/PVC-CF were demonstrated from the results of isotherm and kinetic experiments. The pseudo-first order kinetic model was adequate to describe kinetic data obtained at 25 and 50 mg/L, and the pseudo-second-order model was suitable for 100 and 200 mg/L. The isotherm data fitted well to the Langmuir model and the maximum uptake was evaluated to be 217.31 mg/g. According to thermodynamic studies, the adsorption process of Pt(IV) by PEI/PVC-CF was endothermic and spontaneous. The mixture of HCI and thiourea was also used as an eluent for desorption of Pt(IV) from loaded-adsorbent. As a result, nearly 100% of desorption efficiency was achieved at above 20 mM thiourea concentration in 0.01 M HCI. Besides, the sorption-desorption experiments exhibited that the PEI/PVC-CF could be reused repeatedly at least five cycles. The reusability and applicability of PEI/PVC-CF was also verified in a column system. (C) 2017 Elsevier Ltd. All rights reserved.