title: Vibrational spectroscopy of the multi-anion mineral zykaite Fe4(AsO4)(SO4)(OH)·15H2O-implications for arsenate removal.
abstract: Some minerals are colloidal and are poorly diffracting. Vibrational spectroscopy offers one of the few methods for the assessment of the structure of these types of minerals. Among this group of minerals is zykaite with formula Fe(4)(AsO(4))(SO(4))(OH)·15H(2)O. The objective of this research is to determine the molecular structure of the mineral zykaite using vibrational spectroscopy. Raman and infrared bands are attributed to the AsO(4)(3-), SO(4)(2-) and water stretching vibrations. The sharp band at 3515 cm(-1) is assigned to the stretching vibration of the OH units. This mineral offers a mechanism for the formation of more crystalline minerals such as scorodite and bukovskyite. Arsenate ions can be removed from aqueous systems through the addition of ferric compounds such as ferric chloride. This results in the formation of minerals such as zykaite and pitticite (Fe(3+), AsO(4), SO(4), H(2)O).
authors.affiliation: Faculty of Science and Technology, Queensland University of Technology, Brisbane, Queensland, Australia. r.frost@qut.edu.au
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Palmer
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Xi
mesh_terms: D001149:Arsenates / Q000302:isolation & purification*; D002712:Chlorides / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D008903:Minerals / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D014867:Water / Q000737:chemistry
chemical_list: D001149:Arsenates; D002712:Chlorides; D005290:Ferric Compounds; D008903:Minerals; D014867:Water; C024555:ferric chloride