Water-solid Suspension Grafting of Dual Monomers on Polypropylene to Prepare Ion-imprinted Fibers for Selective Adsorption of Cr(VI)

In this work, a new strategy was developed to prepare Cr(VI)-imprinted polypropylene (PP) fibers-based materials for the adsorption of Cr(VI) from water. Granular PP was modified with dual monomers (glycidyl methacrylate (GMA) and acrylamide (AM)) by water-solid suspension grafting copolymerization. Then, this fibers morphology was obtained by melt-blowing. Hence, the preparation steps of the fibrous Cr(VI)-imprinted adsorbent involved surface ion-imprinting and crosslinking. The influence of the grafting conditions on the grafting percentage was investigated. The maxima grafting percentages of GMA and AM were 16.4 and 10.6 %, respectively. The chemically modified products showed good mobility and stability, thus meeting the requirements of melt-blowing method. The prepared Cr(VI)-imprinted polymers showed a maximum adsorption capacity to Cr(VI) of 43.2 mg/g at pH 3. The adsorption data were well fitted by the pseudo-second-order and Langmuir adsorption models. The adsorbent showed good selectively toward Cr(VI) in a mixed solution containing Cu(II) and SO42−. The X-ray photoelectron spectroscopy demonstrated that the adsorbed Cr(VI) was partly reduced to Cr(III).