title: Arsenite oxidation by a poorly-crystalline manganese oxide. 3. Arsenic and manganese desorption.
abstract: Arsenic (As) mobility in the environment is greatly affected by its oxidation state and the degree to which it is sorbed on metal oxide surfaces. Manganese oxides (Mn oxides) have the ability to decrease overall As mobility both by oxidizing toxic arsenite (As(III)) to less toxic arsenate (As(V)), and by sorbing As. However, the effect of competing ions on the mobility of As sorbed on Mn-oxide surfaces is not well understood. In this study, desorption of As(V) and As(III) from a poorly crystalline phyllomanganate (δ-MnO(2)) by two environmentally significant ions is investigated using a stirred-flow technique and X-ray absorption spectroscopy (XAS). As(III) is not observed in solution after desorption under any conditions used in this study, agreeing with previous studies showing As sorbed on Mn-oxides exists only as As(V). However, some As(V) is desorbed from the δ-MnO(2) surface under all conditions studied, while neither desorptive used in this study completely removes As(V) from the δ-MnO(2) surface.
authors.affiliation: Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, 152 Townsend Hall, Newark, Delaware 19716, United States. blafferty@gmail.com
authors.forename: Brandon J
authors.initials: BJ
authors.lastname: Lafferty
authors.forename: Matthew
authors.initials: M
authors.lastname: Ginder-Vogel
authors.forename: Donald L
authors.initials: DL
authors.lastname: Sparks
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry*; D018053:Arsenites / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D018053:Arsenites; D017895:Manganese Compounds; D010087:Oxides; D008345:Manganese; C027424:manganese oxide; C015001:arsenite; D001151:Arsenic