Permeable reactive barrier containing zero valent iron has become a popular technology for in situ bioremediation of groundwater contaminated with chlorinated organic compounds. The electrochemical investigation of the rate limiting mechanisms for trichloroethylene (TCE) and carbon tetrachloride (CT) reduction at iron surfaces was conducted. The transfer coefficient for CT reduction was independent of temperature, while that for TCE reduction was temperature dependent. This indicated that the rate of CT reduction was limited by an electron transfer step, while that for TCE was limited by chemical dependent factors. The apparent activation energies (Ea) for CT reduction decreased with increasingly negative electrode potentials. In contrast to CT, the Ea values of TCE exhibited a slight increase with decreasing E. The rates of CT reduction at iron surfaces were limited by the rate of electron transfer, while rates of TCE reduction were limited by chemical dependent factors.
ASJC Scopus subject areas
- Chemical Engineering(all)