title: Carbon isotope fractionation of 1,1,1-trichloroethane during base-catalyzed persulfate treatment.
abstract: The extent of carbon isotope fractionation during degradation of 1,1,1-trichloroethane (1,1,1-TCA) by a base-catalyzed persulfate (S₂O₈(2-)) treatment system was investigated. Significant destruction of 1,1,1-TCA was observed at a pH of ∼12. An increase in the NaOH:S₂O₈(2-) molar ratio from 0.2:1 to 8:1 enhanced the reaction rate of 1,1,1-TCA by a factor of ∼5 to yield complete (>99.9%) destruction. An average carbon isotope enrichment fractionation factor which was independent of the NaOH:S₂O₈(2-) molar ratio of -7.0 ± 0.2‰ was obtained. This significant carbon isotope fractionation and the lack of dependence on changes in the NaOH:S₂O₈(2-) molar ratio demonstrates that carbon isotope analysis can potentially be used in situ as a performance assessment tool to estimate the degradation effectiveness of 1,1,1-TCA by a base-catalyzed persulfate system.
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1. m2marche@uwaterloo.ca
authors.forename: Massimo
authors.initials: M
authors.lastname: Marchesi
authors.forename: Neil R
authors.initials: NR
authors.lastname: Thomson
authors.forename: Ramon
authors.initials: R
authors.lastname: Aravena
authors.forename: Kanwartej S
authors.initials: KS
authors.lastname: Sra
authors.forename: Neus
authors.initials: N
authors.lastname: Otero
authors.forename: Albert
authors.initials: A
authors.lastname: Soler
mesh_terms: D002247:Carbon Isotopes / Q000378:metabolism; D002384:Catalysis; D005591:Chemical Fractionation / Q000379:methods*; D006878:Hydroxides / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis; D013431:Sulfates / Q000737:chemistry*; D013997:Time Factors; D014240:Trichloroethanes / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D002247:Carbon Isotopes; D006878:Hydroxides; D017670:Sodium Compounds; D012989:Soil Pollutants; D013431:Sulfates; D014240:Trichloroethanes; D014874:Water Pollutants, Chemical; C024566:1,1,1-trichloroethane; C024625:sodium persulfate; D010100:Oxygen
keywords: 1,1,1-Trichloroethane (1,1,1-TCA); Base-catalyzed persulfate; In situ chemical oxidation (ISCO); Isotope fractionation