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Direct Synthesis of Bacteria-Derived Carbonaceous Nanofibers as a Highly Efficient Material for Radionuclides Elimination

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journal contribution
posted on 09.08.2016, 00:00 by Yubing Sun, Xiangxue Wang, Congcong Ding, Wencai Cheng, Changlun Chen, Tasawar Hayat, Ahmed Alsaedi, Jun Hu, Xiangke Wang
Bacteria-derived carbonaceous nanofibers (CNFs) can be directly synthesized by the pyrolysis of bacterial cellulose pellicles under N2 atmosphere. The batch adsorption experiments showed that the bacteria-derived CNFs displayed the excellent adsorption performance for radionuclides. The maximum adsorption capacities of the CNFs calculated from the Langmuir model at pH 4.5 and 293 K were 67.11 mg/g for Sr­(II) and 57.47 mg/g for Cs­(I). The adsorption of Cs­(I) and Sr­(II) on the CNFs decreased with increasing ionic strength at pH < 5.0, whereas no effect of ionic strength was observed at pH > 6.0, indicating that the outer-sphere surface complexation dominated the radionuclide adsorption at pH < 5.0 whereas the adsorption was attributed to inner-sphere surface complexation at pH > 6.0. The further evidence of surface complexation modeling indicated that Sr­(II) and Cs­(I) adsorption on the CNFs can be satisfactorily fitted by a double diffuse layer model with an outer-sphere (SOHSr2+/SOHCs+) and an inner-sphere complexes (SOSr+/SOCs). The X-ray photoelectron spectroscopy analyses demonstrated that the adsorption of Sr­(II) and Cs­(I) on the CNFs were ascribed to the combination of the oxygenated functional groups of the CNFs. These observations indicated that the CNFs, as inexpensive and available carbon-based nanomaterials, can be regarded as a promising adsorbent for the removal of radionuclides from aqueous solutions in environmental pollution cleanup.