title: Macroscopic and Microscopic Investigation of U(VI) and Eu(III) Adsorption on Carbonaceous Nanofibers.
abstract: The adsorption mechanism of U(VI) and Eu(III) on carbonaceous nanofibers (CNFs) was investigated using batch, IR, XPS, XANES, and EXAFS techniques. The pH-dependent adsorption indicated that the adsorption of U(VI) on the CNFs was significantly higher than the adsorption of Eu(III) at pH < 7.0. The maximum adsorption capacity of the CNFs calculated from the Langmuir model at pH 4.5 and 298 K for U(VI) and Eu(III) were 125 and 91 mg/g, respectively. The CNFs displayed good recyclability and recoverability by regeneration experiments. Based on XPS and XANES analyses, the enrichment of U(VI) and Eu(III) was attributed to the abundant adsorption sites (e.g., -OH and -COOH groups) of the CNFs. IR analysis further demonstrated that -COOH groups were more responsible for U(VI) adsorption. In addition, the remarkable reducing agents of the R-CH2OH groups were responsible for the highly efficient adsorption of U(VI) on the CNFs. The adsorption mechanism of U(VI) on the CNFs at pH 4.5 was shifted from inner- to outer-sphere surface complexation with increasing initial concentration, whereas the surface (co)precipitate (i.e., schoepite) was observed at pH 7.0 by EXAFS spectra. The findings presented herein play an important role in the removal of radionuclides on inexpensive and available carbon-based nanoparticles in environmental cleanup applications.
authors.affiliation: School of Environment and Chemical Engineering, North China Electric Power University , Beijing 102206, P.R. China.|Key Laboratory of New Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences , P.O. Box 1126, Hefei 230031, Anhui, P.R. China.|School for Radiological and Interdisciplinary Sciences, Soochow University and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , 215123 Suzhou, P.R. China.
authors.forename: Yubing
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Science at Microscale, Department of Chemistry, University of Science and Technology of China , Hefei 230026, Anhui, P.R. China.
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Wu
authors.affiliation: School of Environment and Chemical Engineering, North China Electric Power University , Beijing 102206, P.R. China.|Key Laboratory of New Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences , P.O. Box 1126, Hefei 230031, Anhui, P.R. China.
authors.forename: Xiangxue
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of New Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences , P.O. Box 1126, Hefei 230031, Anhui, P.R. China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Ding
authors.affiliation: Key Laboratory of New Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences , P.O. Box 1126, Hefei 230031, Anhui, P.R. China.
authors.forename: Wencai
authors.initials: W
authors.lastname: Cheng
authors.affiliation: Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Science at Microscale, Department of Chemistry, University of Science and Technology of China , Hefei 230026, Anhui, P.R. China.
authors.forename: Shu-Hong
authors.initials: SH
authors.lastname: Yu
authors.affiliation: School of Environment and Chemical Engineering, North China Electric Power University , Beijing 102206, P.R. China.|School for Radiological and Interdisciplinary Sciences, Soochow University and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , 215123 Suzhou, P.R. China.|NAAM Research Group, Faculty of Science, King Abdulaziz University , Jeddah 21589, Saudi Arabia.
authors.forename: Xiangke
authors.initials: X
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D005063:Europium / Q000032:analysis* / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure*; D013499:Surface Properties; D014502:Uranyl Nitrate / Q000032:analysis* / Q000737:chemistry; D014875:Water Pollutants, Radioactive / Q000032:analysis* / Q000737:chemistry; D056928:X-Ray Absorption Spectroscopy
chemical_list: D014875:Water Pollutants, Radioactive; D014502:Uranyl Nitrate; D005063:Europium