title: The mineral tooeleite Fe₆(AsO₃)₄SO₄(OH)₄⋅4H₂O - an infrared and Raman spectroscopic study-environmental implications for arsenic remediation.
abstract: The mineral tooeleite Fe(6)(AsO(3))(4)SO(4)(OH)(4)⋅4H(2)O is secondary ferric arsenite sulphate mineral which has environmental significance for arsenic remediation because of its high stability in the regolith. The mineral has been studied by X-ray diffraction (XRD), infrared (IR) and Raman spectroscopy. The XRD result indicates tooeleite can form more crystalline solids in an acid environment than in an alkaline environment. Infrared spectroscopy identifies moderately intense band at 773 cm(-1) assigned to AsO(3)(3-) symmetric stretching vibration. Raman spectroscopy identifies three bands at 803, 758 and 661 cm(-1) assigned to the symmetric and antisymmetric stretching vibrations of AsO(3)(3-) and As-OH stretching vibration respectively. In addition, the infrared bands observed at 1116, 1040, 1090, 981 and 616 cm(-1), are assigned to the ν(3), ν(1) and ν(4) modes of SO(4)(2-). The same bands are observed at 1287, 1085, 983 and 604 cm(-1) in the Raman spectrum. As(3d) band at binding energy of 44.05eV in XPS confirms arsenic valence of tooeleite is +3. These characteristic bands in the IR and Raman spectra provide useful basis for identifying the mineral tooeleite.
authors.affiliation: The Key Laboratory of Solid Waste Treatment and Resource, Ministry of Education, Southwest University of Science and Technology, 621010 Mianyang, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Hongfei
authors.initials: H
authors.lastname: Cheng
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.forename: Faqing
authors.initials: F
authors.lastname: Dong
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D018053:Arsenites / Q000032:analysis; D007501:Iron / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013431:Sulfates / Q000032:analysis
chemical_list: D018053:Arsenites; D013431:Sulfates; C477679:tooeleite; D007501:Iron; C015001:arsenite; D001151:Arsenic