Plasma polymerization mediated construction of surface ion-imprinted polypropylene fibers for the selective adsorption of Cr(VI)

Abstract

This work reports the preparation of a surface ion-imprinted polymer (IIP) using polypropylene (PP) fibers as substrates for the selective adsorption of Cr(VI). Glycidyl methacrylate was firstly grafted onto PP fibers through a plasma polymerization-induced process, followed by the construction of imprinted sites. The resultant sorbent was characterized using SEM, FT-IR, TGA, XPS, and water contact angle. The results of batch adsorption experiments showed that the maximum Cr(VI) adsorption capacity was 103 mg/g at pH 3 and 25 °C. The Cr(VI) adsorption process followed a pseudo-second-order rate model, and the equilibrium data were best described by a Langmuir isotherm model. Meanwhile, the adsorption process was spontaneous and endothermic. IIP showed a high adsorption selectivity for Cr(VI) in binary systems with Cr3+, Cu2+, and SO42−, respectively, compared with that of non-imprinted fibers. The removal mechanism of Cr(VI) was investigated combining with FT-IR and XPS analysis, and the results suggested that chemical adsorption occurred between the functional groups on IIP and Cr(VI), as did the partial transformation of Cr(VI) to Cr3+. The results demonstrated that the prepared material is a good candidate for selective Cr(VI) adsorption in practical use.