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

Abstract

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 (R_L) 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.

Keywords: starch, Fe₃O₄, Cu(II), adsorption, water pollution