Fabrication of a magnetite/diazonium functionalized-reduced graphene oxide hybrid as an easily regenerated adsorbent for efficient removal of chlorophenols from aqueous solution |
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| Authors: | Xiaoqin Shen Xiaolei Chen Dejun Sun Tao Wu Yujiang Li |
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| Affiliation: | Shandong Provincial Research Center for Water Pollution Control, School of Environmental Science & Engineering, Shandong University, Jinan 250100 PR China, Fax: +86-531-88363358, +86-531-88363358 ; Key Laboratory of Colloid & Interface Science of Education Ministry, Shandong University, Jinan 250100 PR China, Fax: +86-531-88365437, +86-531-88365437 |
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| Abstract: | A magnetic hybrid nanomaterial, which contains magnetite (Fe3O4) particles and diazonium functionalized-reduced graphene oxide (DF-RGO), was fabricated via a three-pot reaction. First, the reduced graphene oxide (RGO) was synthesized via a redox reaction. Second, diazonium functionalized-RGO was prepared via a feasible chemical reaction. Third, Fe3O4 particles were loaded onto the surface of DF-RGO by covalent bonding, fabricating the M-DF-RGO hybrid. The fabricated hybrid was characterized by SEM, TEM, AFM, XRD, XPS, FT-IR, TGA, Raman spectroscopy, and magnetometry. The resulting M-DF-RGO hybrid possessed unique magnetic properties and was applied to remove 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) from aqueous solution. The adsorption of 4-CP and 2,4-DCP on the M-DF-RGO hybrid was performed under various conditions, with respect to initial chlorophenol concentration, pH, and contact time. The results suggest that the adsorption of 4-CP and 2,4-DCP onto the M-DF-RGO hybrid is strongly dependent on pH and weakly dependent on contact time. In addition, the adsorption isotherm of 4-CP and 2,4-DCP on the M-DF-RGO hybrid fits the Freundlich model well and the adsorption capacities of 4-CP and 2,4-DCP on M-DF-RGO reached 55.09 and 127.33 mg g−1, respectively, at pH 6 and 25 °C. In this situation, intermolecular interactions including π–π interactions and hydrogen bonding are operative. The calculated results of density functional theory further demonstrate that 2,4-DCP molecules could be more easily absorbed than 4-CP molecules by the M-DF-RGO hybrid. Moreover, the M-DF-RGO hybrid could be easily separated by a magnetic separation process, and showed good recyclability of more than five cycles.A magnetite/diazonium functionalized-reduced graphene oxide hybrid is an easily regenerated and recyclable adsorbent for removal of chlorophenols from aqueous solution. |
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