Investigation of Stable C and Cl Isotope Effects of Trichloroethene and Tetrachloroethylene during Evaporation at Different Temperatures

• Published in: Journal of earth science (Wuhan, China) Vol. 25; no. 4; pp. 735 - 740
• Main Authors: Yu, Tingting, Gan, Yiqun, Zhou, Aiguo, Yu, Kai, Liu, Yunde
• Format: Journal Article
• Language: English
• Published: Heidelberg China University of Geosciences 01.08.2014; Springer Nature B.V; School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
• Subjects: Biodegradation; Biogeosciences; Carbon; Carbon isotopes; Chlorine; Chlorine isotopes; Contaminants; Earth and Environmental Science; Earth science; Earth Sciences; Enrichment; Environmental conditions; Evaporation; Evaporation rate; Fractionation; Geochemistry; Geology; Geotechnical Engineering & Applied Earth Sciences; Groundwater pollution; Isotope effect; Isotope fractionation; Isotopes; Isotopic enrichment; Organic contaminants; Stable isotopes; Temperature effects; 三氯乙烯; 同位素分馏; 同位素效应; 四氯乙烯; 富集因子; 温度; 稳定同位素; 蒸发过程; chlorinated organic contaminant; groundwater; chlorine isotope; carbon isotope; evaporation; isotope fractionation
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-014-0461-3

There are variations of reported isotope enrichment factors of chlorinated organic contaminants in evaporation processes. Trichloroethene （TCE） and tetrachloroethylene （PCE） were chosen to study carbon and chlorine isotope effects during evaporation at different temperatures. Equilibrium vapor-liquid carbon and chlorine isotope effects experiments were also conducted. In the equilibrium liquid-vapor system, the 13C was enriched but 37Cl was depleted in the vapor phase, being consistent with previous results. For evaporation average carbon isotope enrichment factor εc were ＋0.28‰± 0.01‰ for TCE and ＋0.56‰±0.09‰ for PCE at temperature from 20 to 26 ℃. Meanwhile, average chlorine isotope enrichment factor εCl were -1.33‰±0.21‰ for TCE and -1.00‰±0.00‰ for PCE. The results indicate that during evaporation the equilibrium isotope effect attenuates the magnitude of carbon isotope fractionation whereas enhances the chlorine isotope effect. Isotope fractionation during evaporation is determined by both equilibrium and kinetic factors. Chlorine isotope fractionation is influenced by the evaporation rate which is linked to temperature. When using stable isotope to inves- tigate the behavior of chlorinated organic contaminants in groundwater with slow biodegradation rate, the isotope fractionation resulted from evaporation should be taken into consideration. Furthermore, the environment conditions such as temperature are also factors to be considered.