Reductive Dehalogenation at Electrodes

EPA Grant Number: GF9500575
Title: Reductive Dehalogenation at Electrodes
Investigators: Presley, Richard
Institution: New Mexico Highlands University
EPA Project Officer: Michaud, Jayne
Project Period: May 1, 1995 through January 1, 2000
Project Amount: $23,830
RFA: STAR Graduate Fellowships (1995) Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Chemistry


For this project a new pump and treat method is proposed in which halocarbon contaminated groundwater is detoxified by passage over carbon cathods. These contaminants rank prominantly in frequency of occurrence at superfund sites. Many of these resist oxidative treatment , hence reductive treatments are needed. The kinetics, products and mass balances of reduction of Ccl4, C2Cl4, and C6Cl6 at carbon cathods will be studied. Both bare and devitalized C electrodes will be used. This technology may also be effective in treatment of nitroaromatics and nitrosamines. Currently the best available treatment technique for the destruction of these chlorinated volatile organic compounds appears to be air stripping followed by catalytic oxidation. Draw -backs to this method are largely the result of incomplete oxidation. Direct reduction of halocarbons at metal surfaces, electrodes, and photoelectrodes has seen only modest investigation for potential treatment methods. Three important criteria that will determine the value of such techniques are the absolute reaction rates for halocarbon reduction; the extent of dechlorination; and the relative rates of water electrolysis vs. Dechlorination. The work will involve bench-scale studies initially focused on the efficacy of bare electrodes. The controlled potential electrolysis with coulometry in gas tight cells gives the necessary information to establish the energy efficiency. Sampling of gas and liquid phases and analysis by GC-MS and GC-EC afford the fate and rate data. The reaction will be studied as a function of pH applied potential, ionic strength, aerobically and in the presence of nitrates. Depending on the initial findings electrode derivation will be investigated.

Supplemental Keywords:

Scientific Discipline, Waste, Chemical Engineering, Environmental Chemistry, Chemistry, Analytical Chemistry, Groundwater remediation, Environmental Engineering, dechlorination, reductive dehalogenation, devitalized C electrodes, electrodes, Cc14, C2Cl4, dehalogenation, contaminated groundwater, groundwater contamination, reductive dechlorination, reductive dechlorination rates, C6C16, carbon cathods, groundwater, halocarbon reaction rates

Progress and Final Reports:

  • 1995
  • 1996
  • 1997
  • 1998
  • Final