Synthesis of novel resin containing carbamothiolylimidamide group and application for Cr(VI) removal

In this study, a new adsorbent was prepared to remove chromium (Cr(VI)) ions, which adversely affect human health even at low concentrations, from aqueous solutions and were characterized by FTIR, TGA, SEM, and BET analysis. The neutral pH point of adsorbent was determined. Later, the effects of initial ion concentration, pH, temperature, time, and amount of adsorbent on adsorption were investigated. Moreover, effect on Cr(VI) ion adsorption on both anions, such as nitrate and sulfate, and cations, such as lead, cadmium, and nickel, was also investigated. In addition, isotherm, kinetic and thermodynamic studies were also carried out. It was found that adsorption equilibrium time was 6 h, optimum pH was 2, the adsorption amount of chrome increased with increasing chrome concentration and increasing temperature. Cr(VI) ion adsorption data showed compliance with the best Langmuir isotherm and adsorption capacity of adsorbent was found to be 88.5, 103.1, and 107.5 mg/g at 298, 308, and 318 K, respectively. From kinetic data, adsorption of Cr(VI) onto developed adsorbent was found to comply with pseudo-second-order kinetic model. From the results of thermodynamic study, it was determined that the adsorption was endothermic and spontaneous. Cr(VI) ion adsorption of prepared adsorbent was not affected both in the presence of anions such as nitrate (NO3 (-)) and sulfate (SO4 (2-)) and in the presence of toxic metal ions such as Pb2+, Ni2+, and Cd2+ at pH 2, that is, the adsorbent was found to be selective for Cr(VI) ions. Furthermore, prepared adsorbent, applied to actual industrial wastewater, exhibited good performance for the removal of Cr(VI) ions.