Nonideal transport of reactive contaminants in heterogeneous porous media: 7. Distributed-domain model incorporating immiscible-liquid dissolution and rate-limited sorption/desorption

Zhihui Zhang, Mark L. Brusseau

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The purpose of this work is to present a distributed-domain mathematical model incorporating the primary mass-transfer processes that mediate the transport of immiscible organic liquid constituents in water-saturated, locally heterogeneous porous media. Specifically, the impact of grain/pore-scale heterogeneity on immiscible-liquid dissolution and sorption/desorption is represented in the model by describing the system as comprising a continuous distribution of mass-transfer domains. With this conceptualization, the distributions of the initial dissolution rate coefficient and the sorption/desorption rate coefficient are represented as probability density functions. Several sets of numerical experiments are conducted to examine the effects of heterogeneous dissolution and sorption/desorption on contaminant transport and elution. Four scenarios with different combinations of uniform/heterogeneous rate-limited dissolution and uniform/heterogeneous rate-limited sorption/desorption are evaluated. The results show that both heterogeneous rate-limited sorption/desorption and heterogeneous rate-limited dissolution can significantly increase the time or pore volumes required to elute immiscible-liquid constituents from a contaminated porous medium. However, sorption/desorption has minimal influence on elution behavior until essentially all of the immiscible liquid has been removed. For typical immiscible-liquid constituents that have relatively low sorption, the asymptotic elution tailing produced by heterogeneous rate-limited sorption/desorption begins at effluent concentrations that are several orders of magnitude below the initial steady-state concentrations associated with dissolution of the immiscible liquid. Conversely, the enhanced elution tailing associated with heterogeneous rate-limited dissolution begins at concentrations that are approximately one-tenth of the initial steady-state concentrations. Hence, dissolution may generally control elution behavior of immiscible-liquid constituents in cases wherein grain/pore-scale heterogeneity significantly influences both dissolution and sorption/desorption.

Original languageEnglish (US)
Pages (from-to)83-103
Number of pages21
JournalJournal of Contaminant Hydrology
Volume74
Issue number1-4
DOIs
StatePublished - Oct 2004

Keywords

  • Contaminant transport
  • Dissolution
  • Heterogeneous
  • Immiscible-liquid
  • Mathematical modeling
  • Sorption/desorption

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology

Fingerprint Dive into the research topics of 'Nonideal transport of reactive contaminants in heterogeneous porous media: 7. Distributed-domain model incorporating immiscible-liquid dissolution and rate-limited sorption/desorption'. Together they form a unique fingerprint.

Cite this