Wastewater treatment with diamond electrodes

Boron doped diamond films have been deposited by large area hotfilament CVD (HFCVD) on silicon, siliconcarbide and different industrial electrode materials, like niobium, tantalum, titanium, tungsten, zirconium and graphite on areas up to 40 cm x 60 cm (Fig. 1). These diamond electrodes habve been characterized with regard to their material and electrochemical properties. The oxidation of organic compounds has been studied using alcohols, organic acids and halogenated aromatic molecules. These organic model molecules are oxidized to CO2 without major amounts of other detectable byproducts even at very low concentrations (<3ppm). Concentrated (1 M) and diluted (3.1x10-4M) cyanide solutions have been oxidized on diamond electrodes both in the presence and in the absence of chloride ions. At low concentrations, the oxidation process is strongly catalysed by the presence of Cl-. These experimental data demonstrate the applicability of diamond electrodes for industrial processes of wastewater treatment and purification.