Insights into Mechanistic Models for Evaporation of Organic Liquids in the Environment Obtained by Position-Specific Carbon Isotope Analysis

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• 作者：Maxime Julien ; Pierrick Nun ; Richard J. Robins ; G茅rald S. Remaud ; Julien Parinet ; Patrick H枚hener
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：November 3, 2015
• 年：2015
• 卷：49
• 期：21
• 页码：12782-12788
• 全文大小：324K
• ISSN：1520-5851

文摘

Position-specific isotope effects (PSIEs) have been measured by isotope ratio monitoring ¹³C nuclear magnetic resonance spectrometry during the evaporation of 10 liquids of different polarities under 4 evaporation modes (passive evaporation, air-vented evaporation, low pressure evaporation, distillation). The observed effects are used to assess the validity of the Craig鈥揋ordon isotope model for organic liquids. For seven liquids the overall isotope effect (IE) includes a vapor鈥搇iquid contribution that is strongly position-specific in polar compounds but less so in apolar compounds and a diffusive IE that is not position-specific, except in the alcohols, ethanol and propan-1-ol. The diffusive IE is diminished under forced evaporation. The position-specific isotope pattern created by liquid鈥搗apor IEs is manifest in five liquids, which have an air-side limitation for volatilization. For the alcohols, undefined processes in the liquid phase create additional PSIEs. Three other liquids with limitations on the liquid side have a lower, highly position-specific, bulk diffusive IE. It is concluded that evaporation of organic pollutants creates unique position-specific isotope patterns that may be used to assess the progress of remediation or natural attenuation of pollution and that the Craig鈥揋ordon isotope model is valid for the volatilization of nonpolar organic liquids with air-side limitation of the volatilization rate.