Diffusive Fractionation of BTEX and Chlorinated Ethenes in Aqueous Solution: Quantification of Spatial Isotope Gradients

Biao Jin, Massimo Rolle, Ting Li, Stefan B. Haderlein

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Laboratory experiments were performed to investigate and quantify the extent of diffusive isotope fractionation of organic contaminants in aqueous solution. We selected petroleum hydrocarbons (toluene and ethylbenzene, in 1:2 mixtures of labeled (perdeuterated) and nonlabeled isotopologues) and chlorinated solvents (trichloroethene, TCE, and cis-dichloroethene, cis-DCE, at their natural isotopic abundance) as model compounds. The experimental approach using gel diffusion tubes allowed us to resolve concentration and isotopic gradients induced by isotopologue-specific diffusion and to determine aqueous diffusion coefficients in agreement with the values calculated using published empirical correlations. The experimental results were quantitatively evaluated with numerical simulations to determine the aqueous diffusion coefficients, D, and the exponent of the inverse power-law relation between D and the molecular mass of the isotopologues. The results show remarkable diffusive isotope fractionation for all the investigated organic compounds; however, the extent of fractionation was found to be smaller for the chlorinated ethenes and remarkably deviating from an inverse square root relationship between the isotopologues diffusion coefficients and their molecular mass. The outcomes of this study are relevant for the interpretation of isotopic signatures of organic contaminants in environmental systems and for the quantitative application of compound specific isotope analysis (CSLA) that needs to take into account the fractionation effects of both physical and transformation processes.
Original languageEnglish
JournalEnvironmental Science & Technology (Washington)
Volume48
Issue number11
Pages (from-to)6141-6150
Number of pages10
ISSN0013-936X
DOIs
Publication statusPublished - 2014
Externally publishedYes

Keywords

  • isotopologue molecular mass
  • natural isotopic abundance
  • aqueous solution
  • BTEX pollutant
  • chlorinated ethenes pollutant organic contaminant
  • cis-dichloroethene 156-59-2 pollutant chlorinated solvent
  • ethylbenzene 100-41-4 pollutant organic contaminant, petroleum hydrocarbon
  • toluene 108-88-3 pollutant organic contaminant, petroleum hydrocarbon
  • trichloroethene TCE 79-01-6 pollutant chlorinated solvent
  • 04500, Mathematical biology and statistical methods
  • 10060, Biochemistry studies - General
  • 10515, Biophysics - Biocybernetics
  • 37015, Public health - Air, water and soil pollution
  • Computational Biology
  • compound specific isotope analysis laboratory techniques
  • diffusive isotope fractionation laboratory techniques
  • empirical correlation mathematical and computer techniques
  • numerical simulation mathematical and computer techniques
  • Methods and Techniques
  • Models and Simulations
  • Pollution Assessment Control and Management
  • ENGINEERING,
  • ENVIRONMENTAL
  • MOLECULAR-DYNAMICS SIMULATIONS
  • ORGANIC CONTAMINANTS
  • DIFFERENTIAL DIFFUSION
  • SULFATE REDUCTION
  • CARIACO BASIN
  • LIQUID WATER
  • MA DONAHUE
  • C. MEILE
  • TW LYONS
  • JP WERNE
  • ISOTOPIC fractionation
  • Research
  • Diffusion
  • Petroleum chemistry
  • Solutions
  • Trichloroethylene
  • Compound specific isotope analysis
  • Empirical correlations
  • Experimental approaches
  • Fractionation effects
  • Isotope fractionation
  • Laboratory experiments
  • Petroleum hydrocarbons
  • Transformation process
  • Isotopes

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