title: Fractionation and release behaviors of metals (In, Mo, Sr) from industrial sludge.
abstract: Little is known on the fate of rare metals in the environment and the associated risks. The fractionation and release of three metals of an industrial sludge were assessed. The average concentration ranges from 39.3 to 41.5 mg/kg for indium (In), 43.1-77.8 mg/kg for molybdenum (Mo), and 131.1-376.4 mg/kg for strontium (Sr). Sequential extraction results implied that In was mobile, while Mo and Sr were immobile. However, experimental results from effects of Eh/pH revealed that In was slightly mobile under acidic (pH 4.5) in Eh range of 210-260 mV, and immobile under alkaline conditions (9.0) in Eh range of -250 to 125 mV. The release of Mo was slightly mobile under acidic conditions. However, Mo was very mobile under alkaline conditions and it increased with decreasing Eh. The release of Sr was significant under acidic conditions; however, it was immobile under alkaline conditions. Solubility and adsorption as affected by pH, and speciation could explain their release behaviors. Discrepancy in predictions from sequential extraction and actual observation from Eh/pH experiments was discussed.
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106, Taiwan.
authors.forename: J Y
authors.initials: JY
authors.lastname: Chen
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106, Taiwan; Department of Chemical Engineering, Can Tho University, 3-2 Street, Can Tho, Viet Nam.
authors.forename: H V T
authors.initials: HV
authors.lastname: Luong
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106, Taiwan. Electronic address: liu1958@mail.ntust.edu.tw.
authors.forename: J C
authors.initials: JC
authors.lastname: Liu
mesh_terms: D005591:Chemical Fractionation; D004785:Environmental Pollutants / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007204:Indium / Q000737:chemistry; D007220:Industrial Waste; D019216:Metals, Heavy / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry; D010084:Oxidation-Reduction; D012722:Sewage / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D007220:Industrial Waste; D019216:Metals, Heavy; D012722:Sewage; D007204:Indium; D008982:Molybdenum; D013324:Strontium
keywords: Indium; Molybdenum; Redox potential; Sequential extraction; Sludge; Strontium