Preparation and characterization of polymeric microspheres for Cr(VI) extraction

Microspheres (MS) from different polymers were prepared using two routes. Route A: process of phase inversion with solutions of polysulfone (PSf) in dichloromethane (DCM) and polyvinylpyrrolidone (PVP) as additive. Different weight ratios of PSf–PVP were used in the MS preparation. Route B: MS were obtained by cross-linking in emulsion using a commercial silicone as raw material. The obtained MS were analysed according to their morphological–structural characteristics and in relation to their Cr(VI) extraction capacity using impregnated MS with Aliquat 336. The results obtained showed that MS prepared with PSf–PVP have both less specific surfaces and relative porosities when the proportion of PVP in the mixture is increased. Extraction tests of ion Cr(VI) indicated that synthesized MS have adequate structural characteristics and interesting adsorptive properties which give rise to impregnating selective extractants. Impregnated microspheres with Aliquat 336 prepared from 2:1 PSf–PVP ratio achieved the highest Cr(VI) extractive performance (92% of Cr extraction for contact time of 60 min) and the best breakthrough point in column tests (up to 10 h in the first cycle).