AWWA WQTC55171

Reactions of trichloroacetic acid (TCAA), tribromoacetic acid (TBAA), chlorodibromoacetic acid (CDBAA) and bromodichloroacetic acid (BDCAA) with Fe 0 were run for periods up to 94 hours in the laboratory. All of the trihaloacetic acids readily reacted with Fe 0 and the reactions proceeded via sequential hydrogenolysis. Bromine was preferentially removed over chlorine in experiments with CDBAA and BDCAA. In the TBAA experiment, three bromine atoms were removed and acetate was formed as the final product. Chloroacetic acid (CAA) appeared to be the final product of reduction of TCAA, CDBAA and BDCAA in experiments run for 94 hours or less. However, additional experiments CAA slowly reacted with Fe 0 and acetate was the final product. The pseudo 1 st order rate constant of reduction of CAA by Fe 0 was 0.0008 h -1 at pH 7.5. Includes 8 references, figures.