期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 610, 期 -, 页码 495-502出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2017.08.063
关键词
Isotopic fractionation; Phase-transfer kinetics; Diffusion; Partitioning; Solvent extraction; Evaporation
Diffusive isotope fractionation of organic compounds in aqueous solution was investigated by means of liquid-liquid and liquid-gas partitioning experiments under kinetic control. The two-film model was used to describe phase-transfer kinetics. It assumes the diffusion of solutes across a stagnant water boundary layer as the rate-controlling step. For all investigated solutes (benzene-D-0 and -D-6, toluene-D-0, -D-5, and -D-8, cyclohexane-D-0 and -D-12), there was no significant observable fractionation effect between nondeuterated and perdeuterated isotopologues, resulting in a ratio of diffusion coefficients D-light: D-heavy= 1.00 +/- 0.01. In addition, isotope fractionation due to equilibrium partitioning of solutes between water and n-octane or gas phase was measured. The deuterated compounds are more hydrophilic than their light isotopologues in all cases, giving rise to fractionation coefficients alpha H-part = K-octane/water, H: K-octane/water,K-D = 1.085 to 1.15. Thus, thermodynamic fractionation effects are much larger than diffusion fractionation effects. Methodical and environmental implications of these findings are discussed. (C) 2017 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据