Electrolytic oxidation of trichloroethylene using a ceramic anode

Trichloroethylene (TCE) was transformed to CO₂, CO, Cl^- and ClO₃^- at the anode of a two-chambered electrolytic cell. The working electrode was constructed from Ebonex, an electrically conductive ceramic (Ti₄O₇). Under our experimental conditions (anode potential E_a = 2.5 to 4.3 V vs SSCE), the disappearance of TCE was first order in TCE concentration. The transformation rate was independent of pH in the range 1.6<pH<11. TCE oxidation occurred only on the anodic surface and was limited by mass transport at high potentials (E_a>4.0 V). The maximum (transport-limited), surface-area-normalized rate constant was about 0.002 43 cm s^-1. Carbon-containing products included CO₂ primarily with traces of CO. At neutral and alkaline pHs, the only chlorine-containing products were Cl^- and ClO₃^-. Hydroxyl radicals were detected in the anodic compartment using a spin trap (4-POBN). A kinetic model was successfully correlated with experimental results.