Preparation and application of acrylic polymer modified magnetic starch adsorption materials

Abstract

Heavy metal ion wastewater is very harmful to human body and environment, and the adsorption materials used in traditional adsorption methods such as starch cellulose are easily hydrolyzed, resulting in secondary pollution to water. In this paper, acrylic polymers such as polyacrylate /polyglycidyl methacrylate/polyhydroxyethyl methacrylate were grafted onto magnetic starch by grafting polymerization to improve the hydrolysis and adsorption properties of starch. Acrylic polymers modified magnetic starch materials St/Fe3O4-g-pAA, St/Fe3O4-g-pHEMA and St/Fe3O4-g-pGMA were prepared, and their properties as adsorbents for Cu(II) removal were studied. The adsorption experiment results show that St/Fe3O4-g-pAA has the best adsorption performance under the same adsorption conditions. The maximum unit adsorption capacity of St/Fe3O4-g-pAA was 78.1 mg/g under the optimum adsorption conditions of 20 mg/L initial concentration of copper ion solution, pH value of solution 7 and adsorption time 160 min. St/Fe3O4-g-pGMA has the best stability and the best reproducibility and can retain 95.7% of the first adsorption effect after 8 adsorption cycles. The adsorption properties of St/Fe3O4-g-pHEMA are the least dependent on pH value. The adsorption processes of the three acrylic polymers modified magnetic starch adsorption materials all follow the Langmuir isotherm model, which is more consistent with the second-order II kinetic model, indicating that the three acrylic polymers modified magnetic starch adsorption materials are mainly chemisorbed and occur on the single molecular layer. The thermodynamics of adsorption process was studied and the data show that adsorption process belongs to endothermic reaction and temperature rise was conducive to adsorption.