A hierarchically structured manganese ferrite microsphere-coated magnetic biochar (BC) composite (MS-MnFe2O4/MBC) was synthesized by a facile solvothermal process to remove Sb(V) from aqueous solutions. In addition to conventional analytical techniques (e.g., XRD, SEM, TEM, XPS), X-ray absorption spectroscopy (XAS) measurements, including X-ray absorption near edge structure and extended X-ray absorption fine structure, were employed to characterize the synthesized MS-MnFe2O4/MBC and to explore its mechanism of interaction with Sb(V) in aqueous solutions. Hierarchically structured single-phase MnFe2O4 microspheres composed of numerous nanocrystallites (6.5–7 nm) were successfully fabricated on the BC surface. The XAS analysis results indicated that MnFe2O4 microspheres consisted of Mn2+ and Fe3+ atoms and possessed a partially inverse spinel structure with an inversion degree of 0.4. After adsorption, the combined results of X-ray photoelectron spectroscopy and XAS analyses demonstrated that the valence state of the adsorbed Sb species was Sb(V), and that its interaction with MS-MnFe2O4/MBC was attributed to the inner-sphere surface complexation through bidentate mononuclear edge-sharing and bidentate binuclear corner-sharing. The high potential of the adsorbent for Sb(V) removal was demonstrated in two actual water matrices, viz., tap water and river water. Overall, the findings indicate that MS-MnFe2O4/MBC has excellent practical applicability for Sb(V) removal from contaminated water.
Bibliographical noteFunding Information:
This study was supported by National R&D Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (2020M3H4A3106366) and an institutional program grant (2E31261) from the Korea Institute of Science and Technology. This work was also supported by grants from the National Research Foundation of Korea funded by the Korea government (2020R1I1A1A01073846).
© 2021 Elsevier B.V.
- Adsorption mechanisms
- Magnetic biochar composite
- Spinel manganese ferrite microspheres
- X-ray absorption spectroscopy
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Surfaces and Interfaces