In situ nano-silicate functionalized magnetic composites by (poly)dopamine to improve MB removal

A novel magnetic adsorbent Fe3O4/PDA/Si-Ca-Mg(FPS) was successfully synthesized for methylene blue(MB) removal in this investigation. The preparation of the composite was realized by dopamine which acted likely as a coupling agent between Fe3O4 and silicate. Briefly, dopamine wrapped tightly around the surface of Fe3O4 through self-polymerization. On the other hand, hydroxyl groups in dopamine could anchor metal ions like Ca2+ or Mg2+ and acted as outside growth centers of silicates. Properties of the material were characterized by X-Ray Diffraction(XRD), Fourier Transform Infrared Spectrometry(FT-IR), Scanning Electron Microscope -Energy Disperse Spectroscopy(SEM-EDS) and Transmission Electron Microscopy (TEM). During the adsorption process, experimental factors and thermodynamic and kinetic were studied to investigate the adsorption characteristics of the material, and the result showed that adsorption capacity for MB could reach 100.23 mg/g. Besides, the composite also could be utilized as the recyclable adsorbent by degradation experiment. This study introduced an appealing idea in effectively improving separability and further recyclability of silicate adsorbents.