The basic chemical reaction utilises a catalyst to convert sodium hypochlorite to brine and a highly reactive oxygen atom held on the surface of the catalyst (reaction 1). This oxygen species is responsible for the enhanced oxidation of organic contaminants in an aqueous stream. The transformation of the catalyst surface producing an adsorbed oxygen species provides a powerful medium capable of oxidizing almost any organic compound (reactions 2&3). Reaction 3 represents multiple oxidations to mineralization.

The reactions taking place over the catalyst are summarized and shown diagrammatically opposite.

ACCENT reaction

The process is known as Catalytically Enhanced Hypochlorite Oxidation or, more broadly, Active Oxygen Transfer Catalysis. Although prevailing economics favour sodium hypochlorite, the oxidant may also be supplied as hydrogen peroxide or other active oxygen supplying oxidants. The promoted nickel oxide catalyst holds active oxygen on the catalyst surface and also acts as an adsorbent for organics (e.g. R above) and COD (Chemical Oxygen Demand) from the aqueous stream.

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