THE EFFECT OF COPPER AND IRON COMPLEXATION ON REMOVAL OF CYANIDE BY OZONE

Oxidation of cyanide by ozone in basic aqueous solution was studied in the absence and presence of copper and iron. Free cyanide was oxidized via a fast reaction under mass-transfer-limited conditions. Copper catalyzed the oxidation of cyanide further by entering into an oxidation-reduction reaction. Oxidation of cyanide consumed equal moles of ozone and produced equal moles of cyanate. Upon prolonged ozonation, cyanate was converted to carbon dioxide. Complexation of cyanide with iron hindered the oxidation reaction. Under the experimental conditions, oxidation of each mole of iron-complexed cyanide to carbon dioxide required the consumption of more than 30 mol of ozone. Cyanate was not detected during ozonation of iron-cyanide complex.