Mechanistic approach to multi-element isotope modeling of organic contaminant degradation

Biao Jin, Massimo Rolle

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We propose a multi-element isotope modeling approach to simultaneously predict the evolution of different isotopes during the transformation of organic contaminants. The isotopic trends of different elements are explicitly simulated by tracking position-specific isotopologues that contain the isotopes located at fractionating positions. Our approach is self-consistent and provides a mechanistic description of different degradation pathways that accounts for the influence of both primary and secondary isotope effects during contaminant degradation. The method is particularly suited to quantitatively describe the isotopic evolution of relatively large organic contaminant molecules. For such compounds, an integrated approach, simultaneously considering all possible isotopologues, would be impractical due to the large number of isotopologues. We apply the proposed modeling approach to the degradation of toluene, methyl tert-butyl ether (MTBE) and nitrobenzene observed in previous experimental studies. Our model successfully predicts the multi-element isotope data (both 2D and 3D), and accurately captures the distinct trends observed for different reaction pathways. The proposed approach provides an improved and mechanistic methodology to interpret multi-element isotope data and to predict the extent of multi-element isotope fractionation that goes beyond commonly applied modeling descriptions and simplified methods based on the ratio between bulk enrichment factors or on linear regression in dual-isotope plots. © 2013 Elsevier Ltd.
Original languageEnglish
JournalChemosphere
Volume95
Pages (from-to)131-139
Number of pages9
ISSN0045-6535
DOIs
Publication statusPublished - 2014
Externally publishedYes

Keywords

  • Environmental Chemistry
  • Chemistry (all)
  • Isotope modeling
  • MTBE
  • Multi-element isotope analysis
  • Nitrobenzene
  • Stable isotope fractionation
  • Toluene
  • Contaminant degradation
  • Degradation pathways
  • Isotope analysis
  • Isotope fractionation
  • Methyl tert butyl ether
  • Organic contaminant
  • Stable isotope fractionations
  • Isotopes
  • hydrogen
  • isotope
  • methyl group
  • nitrobenzene
  • nitrogen
  • stable isotope
  • tert butyl methyl ether
  • toluene
  • degradation
  • isotopic fractionation
  • organic pollutant
  • article
  • chemical reaction kinetics
  • fractionation
  • hydrolysis
  • isotope analysis
  • nonhuman
  • oxidation
  • reaction analysis
  • reaction time

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