Catalytic reduction of organohalides at hemin and hemin–imidazole polymer films on pyrolytic graphite electrodes

The electrochemical properties of cast films of hemin-dioctadecyldimethylammonium bromide and a hemin–imidazole complex polymer, HmP, on basal plane pyrolytic graphite (BPG) electrodes were investigated and compared to those previously reported at a hemin cast (or adsorbed) film on a BPG electrode and at a HmP-modified edge plane pyrolytic graphite electrode. By means of four different electrodes, modified with cast (or adsorbed) films of hemin, hemin-dioctadecyldimethylammonium bromide and HmP, as well as of adsorbed hemin film on BPG electrodes, we explored the possibility of the catalytic reduction of organohalides including trichloroacetic acid, dichloroacetic acid, dichloroacetonitrile, dichloroacetone, chloral hydride, monochloroacetic acid, trichloroethanol, tetrachloroethylene, 1,1,1-trichloroethane, chloroform and 1,1,1-trichloroethane. It was found that all of these electrodes reduce trichloroacetic acid, dichloroacetic acid, dichloroacetonitrile, dichloroacetone and chloral hydride catalytically. Among the four modified electrodes, the efficiency of the catalytic reduction is the highest at the HmP-modified electrode.