Abiotic degradation rates for carbon tetrachloride and chloroform: Final report. Metadata

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Title

  • Main Title Abiotic degradation rates for carbon tetrachloride and chloroform: Final report.

Creator

  • Author: Amonette, James E.
    Creator Type: Personal
  • Author: Jeffers, Peter M.
    Creator Type: Personal
  • Author: Qafoku, Odeta
    Creator Type: Personal
  • Author: Russell, Colleen K.
    Creator Type: Personal
  • Author: Humphrys, Daniel R.
    Creator Type: Personal
  • Author: Wietsma, Thomas W.
    Creator Type: Personal
  • Author: Truex, Michael J.
    Creator Type: Personal

Contributor

  • Sponsor: United States. Department of Energy.
    Contributor Type: Organization

Publisher

  • Name: Pacific Northwest National Laboratory (U.S.)
    Place of Publication: Richland, Washington
    Additional Info: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)

Date

  • Creation: 2012-12-01

Language

  • English

Description

  • Content Description: This report documents the objectives, technical approach, and progress made through FY 2012 on a project initiated in FY 2006 to help address uncertainties related to the rates of hydrolysis in groundwater for carbon tetrachloride (CT) and chloroform (CF). The project also sought to explore the possible effects of contact with minerals and sediment (i.e., heterogeneous hydrolysis) on these rates. We conducted 114 hydrolysis rate experiments in sealed vessels across a temperature range of 20-93 °C for periods as long as 6 years, and used the Arrhenius equation to estimate activation energies and calculate half-lives for typical Hanford groundwater conditions (temperature of 16 °C and pH of 7.75). We calculated a half-life of 630 years for hydrolysis for CT under these conditions and found that CT hydrolysis was unaffected by contact with sterilized, oxidized minerals or Hanford sediment within the sensitivity of our experiments. In contrast to CT, hydrolysis of CF was generally slower and very sensitive to pH due to the presence of both neutral and base-catalyzed hydrolysis pathways. We calculated a half-life of 3400 years for hydrolysis of CF in homogeneous solution at 16 °C and pH 7.75. Experiments in suspensions of Hanford sediment or smectite, the dominant clay mineral in Hanford sediment, equilibrated to an initial pH of 7.2, yielded calculated half-lives of 1700 years and 190 years, respectively, at 16 °C. Experiments with three other mineral phases at the same pH (muscovite mica, albite feldspar, and kaolinite) showed no change from the homogeneous solution results (i.e., a half-life of 3400 years). The strong influence of Hanford sediment on CF hydrolysis was attributed to the presence of smectite and its ability to adsorb protons, thereby buffering the solution pH at a higher level than would otherwise occur. The project also determined liquid-vapor partition coefficients for CT under the temperatures and pressures encountered in the sealed vessels that differ significantly from extrapolations of published Henry’s Law coefficients.
  • Physical Description: PDFN

Subject

  • Keyword: Kaolinite
  • Keyword: Heterogeneous
  • Keyword: Hanford
  • Keyword: Homogeneous
  • Keyword: Chloroform
  • Keyword: Muscovite
  • Keyword: Montmorillonite
  • Keyword: Hydrolysis
  • Keyword: Groundwater
  • Keyword: Carbon Tetrachloride
  • Keyword: Abiotic
  • Keyword: Sediment
  • Keyword: Albite
  • Keyword: Environmental Molecular Sciences Laboratory
  • Keyword: Remediation

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Report

Format

  • Text

Identifier

  • Report No.: PNNL-22062
  • Report No.: RPT-DVZ-AFRI-012
  • Grant Number: AC05-76RL01830
  • DOI: 10.2172/1057834
  • Office of Scientific & Technical Information Report Number: 1057834
  • Archival Resource Key: ark:/67531/metadc837284