title: Improved arsenic(III) adsorption by Al2O3 nanoparticles and H2O2: evidence of oxidation to arsenic(V) from X-ray absorption spectroscopy.
abstract: We have investigated the oxidation of inorganic As(III) with H2O2 catalysed by Al2O3, using X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopy. The effects of different reaction conditions (pH, time and initial H2O2 concentration) were also studied as were the kinetics of the oxidation reaction. We demonstrated that As(III) was oxidized to As(V) in the presence of H2O2 and Al2O3. Furthermore, all arsenic species found on the Al2O3 surface were in the As(V) state. The presence of both Al2O3 and H2O2 was necessary for oxidation of As(III) to take place within the period of time studied. The oxidation kinetics indicate a mechanism where reversible As(III) binding to the alumina surface is followed by irreversible oxidation by H2O2 leading to strongly bound As(V). Results from this study indicate that there is a surface-catalysed oxidation of As(III) on Al2O3 by H2O2, a reaction that can take place in nature and can be of help in the development of novel treatment systems for As(III) removal.
authors: Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden. Electronic address: Linda.Onnby@biotek.lu.se.
authors: Linda
authors: L
authors: Önnby
authors: Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
authors: Prashanth Suresh
authors: PS
authors: Kumar
authors: MAX-IV Laboratory, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden.
authors: Kajsa G V
authors: KG
authors: Sigfridsson
authors: Department of Chemistry, Centre for Analysis and Synthesis, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
authors: Ola F
authors: OF
authors: Wendt
authors: MAX-IV Laboratory, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden.
authors: Stefan
authors: S
authors: Carlson
authors: Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
authors: Harald
authors: H
authors: Kirsebom
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D001151:Arsenic / Q000737:chemistry*; D002384:Catalysis; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D056928:X-Ray Absorption Spectroscopy
chemical_list: D006861:Hydrogen Peroxide; D000537:Aluminum Oxide; D001151:Arsenic
keywords: Al(2)O(3); Arsenic; H(2)O(2); Oxidation; X-ray absorption spectroscopy