Recent developments in production and application of DiaChem®-electrodes for wastewater treatment

Polycrystalline conductive diamond coatings used as electrode materials exhibit outstanding chemical, physical and electrochemical properties. In particular, the high overpotential before water decomposition opens the widest known electrochemical window, which enables new and improved electrochemical processes with high current efficiencies especially for wastewater treatment. In addition to the electrochemical stability even at high doping levels (up to 10,000 ppm boron in the coating) and high current densities (tested for up to 10 4 mA/cm2), such DiaChem electrodes also exhibit excellent corrosion and wear resistance, permitting electrochemical processes even in severe chemical environments.The enhancement of large-scale hot-filament diamond chemical vapor deposition on ceramic and metallic base materials with areas of up to (50x100) cm2 has put DiaChem electrodes in the position of an industrially applicable electrode material. In this paper, we summarize recent scientific and industrial results on the production, characterization and application of DiaChem electrodes especially for electrochemical advanced oxidation processes (EAOP) presented at the 4th International Workshop on Diamond Electrodes at the Fraunhofer IST, Braunschweig from May 17 to 18, 2001.