1. A new magnetic composite with potential application in boron adsorption: Development, characterization, and removal tests
- Author
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José Rafael Cápua Proveti, Willbrynner Pereira Marques, Luana M. de Souza, Eduardo Perini Muniz, Camila N. Pinotti, Jair C. C. Freitas, Edson C. Passamani, Paulo Sérgio da Silva Porto, and Honério Coutinho de Jesus
- Subjects
Orange juice ,Materials science ,Scanning electron microscope ,Composite number ,Inorganic chemistry ,Infrared spectroscopy ,chemistry.chemical_element ,Condensed Matter Physics ,Nanocrystalline material ,Adsorption ,chemistry ,General Materials Science ,Crystallite ,Boron - Abstract
In this work, a new magnetic composite, with good performance in the adsorption of boron from aqueous solutions, is proposed. The composite was prepared from CoFe2O4 and MgO precursors, which were produced by the sol-gel method using orange juice residues. X-ray diffraction, scanning electron microscopy, infrared spectroscopy, 57Fe Mossbauer spectroscopy, and magnetization measurements have indicated that the ferrimagnetic CoFe2O4 nanocrystalline phase is immersed in the MgO matrix. The magnetic composite was applied to boron compounds removal from synthetic effluents (with boron concentrations up to 20 mg L−1), showing up to 92% removal capacity. After the boron adsorption process on the MgO surface, X-ray diffraction, scanning electron microscopy, and infrared spectroscopy results have shown the formation of crystalline Mg(OH)2 (with needle-like structures), and 57Fe Mossbauer spectroscopy has indicated that the fraction of Fe+3 ions in the nanograin surfaces was changed in comparison with the pristine adsorbents. Three possible boron adsorption mechanisms are suggested: adsorption at the Mg(OH)2 crystallite surface, adsorption through the formation of Fe–O–B bonds, and adsorption by an amorphous Mg(OH)2 gel. The pseudo-first order model was successfully used to fit the kinetic adsorption curves, whereas the Freundlich model has described the isotherms, thus indicating a heterogeneous distribution of adsorption heat and affinities. The composite was found to adsorb about 6% more boron than pure MgO and can be recoverable with a permanent magnet.
- Published
- 2022