Design of multi-N-functional magnetic PVA microspheres for the rapid removal of heavy metal ions with different valence

AbstractIn this study, magnetic polyvinyl acetate (MPVA) microspheres were prepared with the inverse suspension cross-linked method by adding magnetic nanoparticles (Fe3O4) into the PVA gel. Then, the resulting MPVA microspheres were modified with amino and ethylenediamine tetra acetic acid (EDTA) groups, which are both associated with nitrogen chelation. The final product, multi-N-functional MPVA (N-MPVA) microspheres, was characterized by scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometer. Characterization results showed that the diameter of N-MPVA was about 10 μm; its saturation magnetization value was 4.89 emu g−1, and it possessed abundant amino and EDTA groups. A series of adsorption experiments were conducted to investigate the adsorption behavior, adsorption kinetics, and isotherms of different mono-, di-, and tri-valent heavy metals, i.e. Ag+, Cu2+, and Cr3+. Results showed that the adsorption capacity of heavy metals with diff...