title: Uranium(VI) reduction by nanoscale zero-valent iron in anoxic batch systems: the role of Fe(II) and Fe(III).
abstract: The role of Fe(II) and Fe(III) in U(VI) reduction by nanoscale zerovalent iron (nanoFe0) was investigated using two iron chelators 1,10-phenanthroline and triethanolamine (TEA) under a CO2-free anoxic condition. The results showed that U(VI) reduction was strongly inhibited by 1,10-phenanthroline and TEA in a pH range from 6.9 to 9.0. For instance, at pH 6.9 the observed U(VI) reduction rates decreased by 81% and 82% in the presence of 1,10-phenanthroline and TEA, respectively. The inhibition was attributed to the formation of stable complexes between 1,10-phenanthroline and Fe(II) or TEA and Fe(III). In the absence of iron chelators, U(VI) reduction can be enhanced by surface-bound Fe(II) on nanoFe0. Our results suggested that Fe(III) and Fe(II) possibly acted as an electron shuttle to ferry the electrons from nanoFe0 to U(VI), therefore a combined system with Fe(II), Fe(III) and nanoFe0 could facilitate U(VI) reductive immobilization in the contaminated groundwater.
authors.affiliation: State Key Laboratory of Bio-Geology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China. yansen2007@gmail.com
authors.forename: Sen
authors.initials: S
authors.lastname: Yan
authors.forename: Yongheng
authors.initials: Y
authors.lastname: Chen
authors.forename: Wu
authors.initials: W
authors.lastname: Xiang
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Bao
authors.forename: Chongxuan
authors.initials: C
authors.lastname: Liu
authors.forename: Baolin
authors.initials: B
authors.lastname: Deng
mesh_terms: D004983:Ethanolamines / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism*; D005296:Ferrous Compounds / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000378:metabolism; D014501:Uranium / Q000378:metabolism*
chemical_list: D004983:Ethanolamines; D005290:Ferric Compounds; D005296:Ferrous Compounds; D010618:Phenanthrolines; D014501:Uranium; C009546:triethanolamine; D007501:Iron; C025205:1,10-phenanthroline