Artificial conductive diamonds (Fig.1) can be produced by the chemical vapor deposition (CVD) method using methane gas as a carbon source. Electrodes made by conductive diamonds have a high over-potential for oxygen evolution in water discharge, allowing an effective production of oxidant species, such as OH radicals and ozone. Compared to noble metal electrodes, diamond electrodes show outstanding stability (Fig.2), and their applications in wastewater treatment, water disinfection, organic/inorganic synthesis, and sensors are currently in development. Ebara Research has been working on the development of large scale and long term stable diamond electrodes for application in wastewater treatment (Fig.3 and 4).
Fig. 1 Poly-crystalline conductive diamond films fabricated by the CVD method.
Fig.2 Stability comparison between diamond and noble metal electrodes.
(After treating industrial wastewater containing salts and organics for 90 hours)
Fig. 3 Automated diamond electrode system for wastewater treatment.
Fig. 4
Example of cost comparison
in terms of industrial wastewater COD and color removal.
