Synthesis of hyper-crosslinked anion exchange resins and their use in the adsorption of hexavalent chromium

In this study, hyper cross-linked anion exchange resins were synthesized and their use in the adsorption of hexavalent chromium (Cr(VI)) was investigated. First 2% divinylbenzene cross-linked poly(vinylbenzyl chloride) was prepared via suspension polymerization, next this polymer was converted to trimethylammonium ion functionalized anion exchange resins with trimethylamine, finally these resins were converted to hyper-crosslinked anion exchange resins with Friedel-Crafts reaction. FTIR, SEM, and BET techniques and elemental analysis were used to characterize the resins. The hexavalent chromium adsorption behavior of the resins was investigated at pH 4.6 and 7.0. A typical adsorption study was carried out with a 25 mL aqueous solution of 10.0 mg K2Cr2O7 and 20.0 mg resin at room temperature. Hyper cross-linked resins showed higher hexavalent chromium adsorption capacities than their previous forms. The kinetics of hexavalent chromium adsorption to the resins are found to be pseudo second-order. The adsorption obeys the Langmuir adsorption isotherm model for the hyper cross-linked resins. Keywords: Resin, Hyper cross-linked, Adsorption, Hexavalent chromium, Cr(VI)