Fabrication of chromium-imprinted polymer: a real magneto-selective sorbent for the removal of Cr(vi) ions in real water samples

Abstract

In this research work, we report a novel chromium-based magnetic ion-imprinted polymer for the selective and sensitive detoxification of hexavalent chromium ions from aqueous systems. A simple and facile co-precipitation method was applied for the fabrication of an amine-functionalized silica-capped iron oxide nanoparticle-based ion-imprinted polymer using dichromate (Cr₂O₇)²⁻ ions as a template, 4-vinylpyradine as a ligand, methyl methacrylate as a functional monomer, ethylene glycol methacrylate (EGDMA) as a crosslinker, and α-α′-azoisobisbutyronitrile (AIBN) as an initiator. Different analytical techniques were used for the characterization of the synthesized materials, including SEM, XRD EDX, and FTIR. To achieve the maximum adsorption capacity, different parameters were optimized during the adsorption and desorption study including pH, adsorbent dose, temperature, analyte concentration, and shaking speed. According to the results, the data follows the Langmuir isotherm model, while the kinetic study was well described by the pseudo-second-order model. The maximum adsorption capability of Cr-MIIP was determined to be 169.49 mg g⁻¹. The relative standard deviation and limit of detection and quantification were found to be 0.81 μg L⁻¹ and 2.7 μg L⁻¹ for this method. Thus, the high adsorption capacity, selectivity, ease of separation, and time-saving property of the Cr(VI)-imprinted silica-amine-functionalized magnetic polymer make it an efficient adsorbent for the selective remediation of hexavalent chromium ions from water bodies.