Synthesis and Characterization of Nanostructured Fe3O4 Micron‐Spheres and Their Application in Removing Toxic Cr Ions from Polluted Water |
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Authors: | Dr. Gang Liu Quan Deng Huimin Wang Shenghong Kang Yong Yang Prof. Dickon H. L. Ng Prof. Weiping Cai Prof. Guozhong Wang |
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Affiliation: | 1. Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (P. R. China);2. Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory (Hong Kong) |
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Abstract: | We present a simple and effective method for the synthesis of nanostructured Fe3O4 micron‐spheres (NFMSs) by annealing hydrothermally formed FeCO3 spheres in argon. The phase structure, particle size, and magnetic properties of the product have been characterized by X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), field‐emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and by means of a superconducting quantum interference device (SQUID). The results have shown that the as‐obtained NFMSs have a diameter of about 5 μm and are composed of nanometer‐sized porous lamellae. The NFMSs have a large specific surface area (135.9 m2 g?1), reductive Fe2+ incorporated into their structure, and intense magnetic properties. These properties suggest that NFMSs have potential application in removing toxic Cr6+ ions from polluted water. At 25 °C, each gram of NFMSs product can remove 43.48 mg of Cr6+ ions, as compared to just 10.2 mg for nanometer‐sized Fe3O4 and 1.89 mg for micron‐sized Fe3O4. The enhanced removal performance can be ascribed to the structural features. Moreover, the Cr6+ ion removal capacity of the NFMSs can reach up to 71.2 mg g?1 at 50 °C. The influencing parameters in the removal of Cr6+ ions, such as contact time, pH, and temperature, have been evaluated. The Cr6+‐removal mechanism has been investigated. We have found that the NFMSs product not only serves as an effective adsorbent to remove toxic Cr6+ ions from polluted water, but also as an effective reductant in reducing the adsorbed toxic Cr6+ ions to much less toxic Cr3+ through the Fe2+ incorporated into its structure. |
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Keywords: | adsorption chromium micron‐spheres nanostructures water treatment |
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