Selective adsorption of Re(VII) by chitosan modified with imidazolium-based ionic liquid

Abstract

In this study, a novel chitosan adsorbent (CS-MEIC) modified by imidazolium-based ionic liquid was prepared for the efficient adsorption of Re(VII). The results indicated that CS-MEIC could obtain higher uptake capacity for Re(VII) when the volume ratio of N-methyl imidazole to epichlorohydrin was 1:2, and the mass of the CS was 0.3 g. The adsorption process was described best by Langmuir monolayer adsorption model, and the maximum adsorption capacity was 185 mg·g−1. The kinetic data could be fitted to a pseudo-second-order equation. Re(VII) was adsorbed on the CS-MEIC by anion exchange confirmed by FTIR, X-ray photoelectron spectroscopy and ion chromatography analysis. In addition, there was a good selectivity adsorption for Re(VII) compared with other coexisting metal ions Mn(II), Fe(III), Cu(II), and Zn(II). Furthermore, five adsorption-elution cycles suggested that the CS-MEIC adsorbent had good durability and efficiency, which was successfully used to recover rhenium with satisfactory results.