Magnetic Supramolecular Hydrogel in Situ Polymerization with Acrylated β-Cyclodextrin for the Efficient Adsorption of Pollutants

Supramolecular hydrogels have significant research implications for the environmental application of dyes and bisphenols wastewater. Herein, a magnetic Fe₃O₄-P(AAm-AMPS-CDA) supramolecular hydrogel is reported, which is constructed by acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, acrylated β-cyclodextrin, and Fe₃O₄ nanoparticles via thermal polymerization, exhibiting good adsorption properties for cationic dyes and bisphenols. UV–vis spectra show that the adsorption efficiencies of the hydrogel reach 96% for crystal violet and 98% for methylene blue. Meanwhile, β-CDA cavities can form an inclusion complex with bisphenols, achieving adsorption efficiencies of 88% for bisphenol A and 69% for bisphenol F, with no significant decrease in adsorption rates even after seven cycles. The adsorption kinetic experiments indicate that the adsorption process follows the pseudo-second-order kinetics model, and the Weber-Morris intraparticle diffusion model reveals the diffusion mechanism. Additionally, in the presence of NaCl and humic acid, the hydrogel still maintains a high adsorption rate, and there is no significant decline in adsorption across different environmental water qualities, indicating that the hydrogel has great application potential. Importantly, the hydrogel exhibits ferromagnetic characteristics, allowing for separation with a magnet after adsorption is complete and facilitating rapid adsorption and separation of pollutants in wastewater.