Synthesis of coated solvent impregnated resins by PVA cross-linked with vapor-phase glutaraldehyde for adsorption of vanadium (IV)

Coated solvent impregnated resins (CSIRs) were prepared by poly(vinyl alcohol) (PVA) cross-linked with vapor-phase glutaraldehyde (GA) (v-CSIRs) and liquid-phase GA (l-CSIRs) on solvent impregnated resins (SIRs) containing bis(2-ethylhexyl)phosphoric acid (D2EHPA) to investigate the effects of different coating methods on the performance of the SIRs. The optimal PVA content and crosslinking time were found to be 3 wt% and 30 min, respectively for producing v-CSIRs with high stability. It is confirmed that the v-CSIRs is more stable and can more effectively prevent the leakage of extractant from SIRs compared with l-CSIRs. The kinetics results demonstrate that the adsorption of V(IV) onto v-CSIRs, l-CSIRs and the uncoated SIRs (UCSIRs) all follow pseudo-second order model, indicating that the presence of the coating films does not change the rate controlling step for the V(IV) adsorption process, but the adsorption rate constant (k2) implies that the film formed on the surfaces of v-CSIRs has lower resistance to mass transfer of V(IV) comparing to that on l-CSIRs. The study verifies that the method of PVA crosslinking with vapor-phase GA is an highly effective and promising technique for preparing CSIRs with high performance.