title: Simultaneous adsorption and reduction of U(VI) on reduced graphene oxide-supported nanoscale zerovalent iron.
abstract: The reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO) composites were synthesized by chemical deposition method and were characterized by SEM, high resolution TEM, Raman and potentiometric acid-base titrations. The characteristic results showed that the nZVI nanoparticles can be uniformly dispersed on the surface of rGO. The removal of U(VI) on nZVI/rGO composites as a function of contact time, pH and U(VI) initial concentration was investigated by batch technique. The removal kinetics of U(VI) on nZVI and nZVI/rGO were well simulated by a pseudo-first-order kinetic model and pseudo-second-order kinetic model, respectively. The presence of rGO on nZVI nanoparticles increased the reaction rate and removal capacity of U(VI) significantly, which was attributed to the chemisorbed OH(-) groups of rGO and the massive enrichment of Fe(2+) on rGO surface by XPS analysis. The XRD analysis revealed that the presence of rGO retarded the transformation of iron corrosion products from magnetite/maghemite to lepidocrocite. According to the fitting of EXAFS spectra, the UC (at ∼2.9Å) and UFe (at ∼3.2Å) shells were observed, indicating the formation of inner-sphere surface complexes on nZVI/rGO composites. Therefore, the nZVI/rGO composites can be suitable as efficient materials for the in-situ remediation of uranium-contaminated groundwater in the environmental pollution management.
authors.affiliation: School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206, P.R. China; Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei, 230031, P.R. China.
authors.forename: Yubing
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei, 230031, P.R. China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Ding
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei, 230031, P.R. China.
authors.forename: Wencai
authors.initials: W
authors.lastname: Cheng
authors.affiliation: School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206, P.R. China; Faculty of Engineering, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Electronic address: xkwang@ipp.ac.cn.
authors.forename: Xiangke
authors.initials: X
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D006108:Graphite; D007501:Iron / Q000737:chemistry*; D053758:Nanoparticles; D010084:Oxidation-Reduction; D014501:Uranium / Q000302:isolation & purification*; D014875:Water Pollutants, Radioactive / Q000302:isolation & purification; D056928:X-Ray Absorption Spectroscopy
chemical_list: D014875:Water Pollutants, Radioactive; D014501:Uranium; D006108:Graphite; D007501:Iron
keywords: Nanoscale zerovalent iron; Radionuclides; Reduced graphene oxide nanosheets; Sorption and reduction; Spectroscopic techniques