title: Mobility and chemical fate of arsenic and antimony in water and sediments of Sarouq River catchment, Takab geothermal field, northwest Iran.
abstract: Arsenic (As) and antimony (Sb) concentrations in water and sediments were determined along flow paths in the Sarouq River, Zarshuran and Agh Darreh streams. The results indicate high As and Sb concentrations in water and sediment samples. Raman spectroscopy shows hematite (α-Fe2O3), goethite [α-FeO(OH)] and lepidocrocite [γ-FeO(OH)] in sediment samples. Calculated saturation indices (SI) indicate oversaturation with respect to amorphous Fe(OH)3 for all samples, but undersaturation with respect to Al and Mn mineral and amorphous phases. Therefore, ferric oxides and hydroxides are assumed to be principal mineral phases for arsenic and antimony attenuation by adsorption/co-precipitation processes. The considerable difference between As and Sb concentration in sediment is due to strong adsorption of As(V) into the solid phase. Also, lower affinity of Sb(V) for mineral surfaces suggests a greater potential for aqueous transport. The adsorption of arsenic and antimony was examined using the Freundlich adsorption isotherm to determine their distribution model in water-sediment system and its compatibility with the existing theoretical model. The results showed that the adsorption behavior of both elements complies with the Freundlich adsorption isotherm.
authors.affiliation: Department of Earth Sciences, Faculty of Sciences, Shiraz University, Shiraz, Iran. Electronic address: rezasharifi@shirazu.ac.ir.
authors.forename: Reza
authors.initials: R
authors.lastname: Sharifi
authors.affiliation: Department of Earth Sciences, Faculty of Sciences, Shiraz University, Shiraz, Iran.
authors.forename: Farid
authors.initials: F
authors.lastname: Moore
authors.affiliation: Department of Earth Sciences, Faculty of Sciences, Shiraz University, Shiraz, Iran.
authors.forename: Behnam
authors.initials: B
authors.lastname: Keshavarzi
mesh_terms: D000327:Adsorption; D000965:Antimony / Q000737:chemistry*; D001151:Arsenic / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D006801:Humans; D007492:Iran; D058085:Iron Compounds; D008903:Minerals; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014876:Water Pollution / Q000517:prevention & control
chemical_list: D005290:Ferric Compounds; D058085:Iron Compounds; D008903:Minerals; D014874:Water Pollutants, Chemical; C094886:goethite; C000499:ferric oxide; D000965:Antimony; D001151:Arsenic
keywords: Freundlich adsorption isotherm; Pollution; Takab; Toxic elements