Preparation and Application of Acrylic Polymer Modified Magnetic Starch Adsorption Materials Used for Removal of Heavy Metals Ion from Water

Heavy metal ion wastewater is extremely harmful to human health and the environment, while the adsorption materials used in traditional adsorption methods such as starch, are easily hydrolyzed, resulting in secondary water pollution. To address this issue, acrylic polymers were grafted onto magnetic starch (St/Fe3O4-g-pAA, St/Fe3O4-g-pHEMA, and St/Fe3O4-g-pGMA) to enhance adsorption properties for Cu(II). Under optimal conditions (dosage of adsorbent was 0.3 mL, initial copper ion concentration of 20 mg/L, pH 7, and adsorption time of 160 min), St/Fe3O4-g-pAA exhibited the highest adsorption capacity of 145 mg/g. St/Fe3O4-g-pGMA maintained 95.7% of its initial adsorption capacity after eight cycles, demonstrating excellent stability and renewable performance. The adsorption properties of St/Fe3O4-g-pHEMA showed minimal dependence on pH value. The non-dimensional constant separation factors (RL) for St/ Fe3O4, St/Fe3O4-g-pHEMA, St/Fe3O4-gAA, and St/Fe3O4-g-pGMA were 0.226, 0.210, 0.321, and 0.172, respectively, all falling within the range of 0 ~ 1, suggesting a favorable and easy adsorption process for Cu(II). Overall, the adsorption processes of all three modified magnetic starch materials followed the Langmuir isotherm model and were better described by the pseudo-second-order kinetic model.