Adsorption of Cu(II) from solution by modified magnetic starch St/Fe3O4-g-p(AA-r-HEMA)

The composite particles (St/Fe3O4) of starch and Fe3O4 were prepared by a co-precipitation method. Then AA and HEMA were grafted and cross-linked on St/Fe3O4 by a one-step method to obtain St/Fe3O4-g-p(AA-r-HEMA). The effects of the adsorbent dosage, pH value, initial Cu(II) concentration, time and temperature on adsorption were studied. Experiments showed that St/Fe3O4-g-p(AA-r-HEMA) showed a good adsorption performance for Cu(II), with a unit adsorption capacity of 75.5 mg g−1 and a maximum removal rate of 95.0%. The adsorption process followed the Langmuir model and the pseudo-second-order kinetic model, was dominated by chemical adsorption, and belonged to single-layer adsorption. Renewable performance studies showed that after 8 adsorption cycles, 91.2% of the first adsorption effect was still retained.