Mixed redox catalytic destruction of chlorinated solvents in soils and groundwater: From the laboratory to the field

Song Gao, Erik Rupp, Suzanne Bell, Martin Willinger, Theresa Foley, Brian Barbaris, Avelino E Saez, Robert G Arnold, Eric Betterton

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

A new thermocatalytic method to destroy chlorinated solvents has been developed in the laboratory and tested in a pilot field study. The method employs a conventional Pt/Rh catalyst on a ceramic honeycomb. Reactions proceed at moderate temperatures in the simultaneous presence of oxygen and a reductant (mixed redox conditions) to minimize catalyst deactivation. In the laboratory, stable operation with high conversions (above 90% at residence times shorter than 1 s) for perchloroethylene (PCE) is achieved using hydrogen as the reductant. A molar ratio of H2/O2 = 2 yields maximum conversions; the temperature required to produce maximum conversions is sensitive to influent PCE concentration. When a homologous series of aliphatic alkanes is used to replace hydrogen as the reductant, the resultant mixed redox conditions also produce high PCE conversions. It appears that the dissociation energy of the C-H bond in the respective alkane molecule is a strong determinant of the activation energy, and therefore the reaction rate, for PCE conversion. This new method was employed in a pilot field study in Tucson, Arizona. The mixed redox system was operated semicontinuously for 240 days with no degradation of catalyst performance and complete destruction of PCE and trichloroethylene in a soil vapor extraction gas stream. Use of propane as the reductant significantly reduced operating costs. Mixed redox destruction of chlorinated solvents provides a potentially viable alternative to current soil and groundwater remediation technologies.

Original languageEnglish (US)
Title of host publicationAnnals of the New York Academy of Sciences
Pages435-445
Number of pages11
Volume1140
DOIs
Publication statusPublished - Oct 2008

Publication series

NameAnnals of the New York Academy of Sciences
Volume1140
ISSN (Print)00778923
ISSN (Electronic)17496632

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Keywords

  • Catalytic destruction
  • Chlorinated solvents
  • Mixed redox catalysis
  • Mixed redox conditions
  • Oxidation
  • PCE conversion
  • Reduction

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Gao, S., Rupp, E., Bell, S., Willinger, M., Foley, T., Barbaris, B., ... Betterton, E. (2008). Mixed redox catalytic destruction of chlorinated solvents in soils and groundwater: From the laboratory to the field. In Annals of the New York Academy of Sciences (Vol. 1140, pp. 435-445). (Annals of the New York Academy of Sciences; Vol. 1140). https://doi.org/10.1196/annals.1454.044