Design and synthesis of α-cyclodextrin/carboxymethyl chitosan-based hydrogel for multipollutant adsorption

The persistent coexistence of heavy metals and organic pollutants in aquatic systems has emerged as a critical challenge in global environmental remediation strategies. The study of materials for simultaneous and efficient removal of multiple pollutants is particularly important. In this study, a three-dimensional reticulated multifunctional adsorbent material, ADS-Gel-1 (α-CD/CMS-P(AA-co-SS)) was constructed based on free radical polymerization using α-cyclodextrin (α-CD) and carboxymethyl chitosan (CMS) as the dual raw materials. Performance tests showed that the material exhibited rapid adsorption kinetics (t ≤ 150 min) for a wide range of pollutants including antibiotics, dyes and heavy metal ions in a complex aqueous environment (pH 3-9), and the adsorption of norfloxacin (NOR), tetracycline hydrochloride (TC), procaine (Pr), methylene blue (MB), Mn(II) and Cu(II) followed the Langmuir model. The adsorption process is a spontaneous reaction, and the adsorption process is exothermic. The maximum adsorption amounts of NOR, TC, Pr, MB, Mn(II) and Cu(II) reached 861.48, 617.08, 829.84, 1667.52, 1054.87 and 1226.00 mg/g, respectively. The adsorption mechanism involves multiple synergistic effects such as host-guest inclusion, π-π stacking, metal coordination and hydrogen bonding networks. In addition, ADS-Gel-1 maintained the removal rate above 49.06 % in five reusable cycles. It provides a novel functional material design strategy for environmental remediation.