An Ion-Imprinted Imidazole-Functionalized Ordered Mesoporous Silica For Selective Removal of Chromium(VI) From Electroplating Effluents

Abstract

In this work, ion imprinted technology incorporated with mesoporous silica materials (MCM-41) to obtain the novel specific adsorbent, ion imprinted mesoporous silica. Cr(VI) imprinted mesoporous silica (Cr(VI)IMS) was synthesized and used for adsorption studies and waste water application. A synthesized imidazolyl silane agent act as the functional monomer in the imprinted process to build up highly ordered functionalized imprinted materials. The chemical composition, thermal stability, porosity and highly ordered morphology were characterized by Fourier transform infrared spectroscopy (FTIR), solid state nuclear magnetic resonance(NMR), Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) respectively. The Brunauer-Emmett-Teller (BET) surface area was 1054.51 m2 g-1 in this study. The Cr(VI)IMS showed great adsorption capacity to hexavalent chromium ions in acidic solution up to 45.6 mg g-1. Cr(VI)IMS displayed much higher adsorption capacity to Cr(VI) ions than other negative ions. The relative selectivity coefficient was 2.56, higher than those of other anions (below 1.5). After eight adsorption-regeneration cycles, the adsorption efficiency of Cr(VI)IMS still reached 92.5%. The Cr(VI)IMS was found to exhibit equivalent property after multiple cycles of experiments, indicating good repeatability and reproducibility.

Special Issue: Hexavalent Chromium: Sources, Toxicity, and Remediation

“…Several methods are utilized to remove chromium from the contaminated site [4][5][6]. These include adsorption and reduction, chemical precipitation, ion exchange, reduction, electrochemical, precipitation, solvent extraction, membrane separation, bioremediation, and by biomimetic recognition using ion imprinted polymers to name but these routes [7].…”