Adsorption of Cr(VI) ions from wastewater using water-based polyacrylic resin
Yunwei Huang, Shao-Yu Lin, Pingke Ai, Chunsheng Li, Feihua Ye, Jiaping Gan, Jiachun Xu, Lingling Su, Qiumin Chen, Junhua Chen, Jiangfei Cao
Abstract
Hexavalent chromium (Cr(VI)) contamination in water poses severe environmental and health risks, necessitating efficient and sustainable removal technologies. A water-based polyacrylic resin was synthesized via inverse emulsion polymerization using methyl methacrylate, acrylic acid, and maleic anhydride, thereby avoiding the use of organic solvents. Under optimal conditions (0.8 g dosage, pH 2, 318 K, 12 h), the resin achieves 98.73% Cr(VI) removal from 1 mg/L wastewater, following the pseudo-second-order kinetic model ( R 2 = 0.9927). Furthermore, the adsorption is well-fitted to the Langmuir model ( R 2 = 0.9911), yielding a calculated maximum adsorption capacity of 142.86 mg/g. FTIR analysis confirms chemisorption via Cr–O bond formation as the key mechanism. Thermodynamic analysis supports this chemisorption dominance, revealing an exothermic process (Δ H = 138.47 kJ/mol) with high spontaneity (Δ G < 0). Characterization via SEM/XRD shows the resin’s 3D porous structure maintains integrity post-adsorption. Significantly, acid–base elution enables high regeneration efficiency (> 93%) over 5 cycles without secondary pollution. These findings highlight the promising potential of the water-based polyacrylic resin as a macromolecular adsorbent for the efficient removal of Cr(VI) ions from wastewater, offering a viable solution for wastewater treatment.