Preparation of Fe3O4/P(U-AM-ChCl) Composite Hydrogel and Study on Its Mechanical and Adsorption Properties

This study employed urea (U), acrylamide (AM), and choline chloride (ChCl) as raw materials to synthesize a deep eutectic solvent (DES), incorporated dispersed Fe3O4 as a filler within the DES, and effectively fabricated Fe3O4/P(U-AM-ChCl) composite hydrogels through in situ polymerization (SP). The hydrogels were analyzed through Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The influence of different Fe3O4 contents on the swelling behavior, anti-fatigue properties, and adsorption efficiency of the composite hydrogels was thoroughly examined. The results indicated that, in comparison to the hydrogel lacking Fe3O4, the hydrogel containing 1 wt% Fe3O4 demonstrated enhanced swelling and anti-fatigue characteristics, with its equilibrium swelling ratio (ESR) increasing by 16.34%, the time to achieve swelling equilibrium decreasing by 60%, the maximum stress recovery rate rising by 7.8%, and the toughness recovery rate improving by 7.28%.The adsorption efficiency of the hydrogel was improved, and adsorption equilibrium was achieved more quickly, due to the supplementary adsorption sites introduced by Fe3O4. When the Fe3O4/P(U-AM-ChCl) composite hydrogel was immersed in a 120 mg/L Cu2+ so-lution for 48 h, the adsorption capacity reached 171.5 mg/g. This study introduces a novel, viable approach for synthesizing hydrogels with reduced pore sizes and enhanced functionality, while also illustrating their prospective utility in water purification applications.