title: Efficient decomposition of a new fluorochemical surfactant: perfluoroalkane disulfonate to fluoride ions in subcritical and supercritical water.
abstract: Decomposition of (-)O3SC3F6SO3(-) in subcritical and supercritical water was investigated, and the results were compared with the results for C3F7SO3(-). This is the first report on the decomposition of perfluoroalkane disulfonates, which are being introduced in electronics industry as greener alternatives to environmentally persistent and bioaccumulative perfluoroalkyl surfactants. Addition of zerovalent iron to the reaction system dramatically increased the yield of F(-) in the reaction solution: when the reaction of (-)O3SC3F6SO3(-) was carried out in subcritical water at 350°C for 6h, the F(-) yield was 70%, which was 23times the yield without zerovalent iron. Prolonged reaction increased the F(-) formation: after 18h, the F(-) yield from the reaction of (-)O3SC3F6SO3(-) reached 81%, which was 2.1times the F(-) yield from the reaction of C3F7SO3(-). Although the reactivity of FeO toward these substrates was lower than zerovalent iron in subcritical water, the reactivity was enhanced when the reaction temperature was elevated to supercritical state, at which temperature FeO underwent in situ disproportionation to form zerovalent iron, which acted as the reducing agent. When the reaction of (-)O3SC3F6SO3(-) was carried out in the presence of FeO in supercritical water at 380°C for 18h, the F(-) yield reached 92%, which was the highest yield among tested.
authors.affiliation: Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan. Electronic address: h-hori@kanagawa-u.ac.jp.
authors.forename: Hisao
authors.initials: H
authors.lastname: Hori
authors.affiliation: Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Saito
authors.affiliation: Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Sakai
authors.affiliation: Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kitahara
authors.affiliation: Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Sakamoto
mesh_terms: D005459:Fluorides / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D005459:Fluorides; D005466:Fluorocarbons; D007501:Iron; D012996:Solutions; D013501:Surface-Active Agents; D062065:Wastewater
keywords: Alternative; Fluorine; Iron; Surfactant