Advanced Electro-Oxidation
Used as key components in appropriate electrochemical methods, Adamant®-Electrodes (Boron Doped Diamond onto doped Silicon substrates) and DiaCell® technology have a huge potential. The high over potentials at which water is oxidized into oxygen and reduced to hydrogen make possible a great number of electrochemical reactions which make water treatment with DiaCell®-Systems extremely interesting.
Doped diamond has the widest known electrochemical window. This unique electrochemical property, together with its extremely high stability in regards to pH, chemicals and high temperature (up to 600°C in an oxygen atmosphere) and its low fouling behavior makes this material of great interest for the generation of powerful oxidants and for water treatment without the addition of chemicals.
Special features of diamond in electrochemistry:
- Extreme electrochemical window before water decomposition open new possibilities for both anodic and cathodic reactions ,
- High efficiency of OH° radicals (2.8V/ENH), used for incineration of all kind of organics in water,
- Complete oxidation of cyanides,
- Ozone production without consumption of the diamond layer,
- Peroxodisulfates, peroxodicarbonate and hydrogen peroxide formation,
- Great aptitude for supporting polarity reversal which allows self-cleaning of the electrode.
DiaCell®-Systems and Adamant®-Electrodes are used for environmentally friendly electrochemical treatment, disinfection of fresh water or treatment of waste water and chemical oxygen demand (COD) removal.
In disinfection applications, doped diamond allows the production of powerful and persistent oxidants, which can be generated either as a combination or selectively depending on water composition and operating conditions. Accessible oxidants and disinfectants are hydrogen peroxide, persulfates, ozone, percarbonates, chlorine, etc.
In waste-water treatment applications, electro-oxidation with diamond electrodes is also referred to as the electrochemical advanced oxidation process. A process such as this which allows the reagent free production of highly reactive hydroxyl radicals represents the new generation of Advanced Oxidation Processes (AOPs)*. Among the main advantages of electro-oxidation on diamond are:
- A reagent free in situ production of hydroxyl radicals and other oxygen-based oxidants,
- Eliminates the need for purchasing and handling chemicals,
- An amazing destruction efficiency on almost all organic pollutants (even non-biodegradable ones).
*AOPs are chemical treatments designed to remove organic and inorganic materials from waste water by oxidation. In such processes, organic pollutants are mineralized by powerful oxidants usually generated from chemicals in combination with UV irradiation or specific catalysts (e.g. Fenton reagents). AOPs result in the generation of hydroxyl radicals and are particularly useful for cleaning biologically toxic or non-degradable materials such as aromatics, pesticides, hydrocarbons and volatile organic compounds in waste water. The pollutants are mainly converted into stable, non-toxic compounds such as water, carbon dioxide, and salt, and the treated water may be reintroduced into waterways or conventional sewage treatment processes.