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USE OF POTASSIUM FERRATE IN OXYGEN DEMAND MEASUREMENT
Citation:
Carr, J. USE OF POTASSIUM FERRATE IN OXYGEN DEMAND MEASUREMENT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-77/099 (NTIS PB271439), 1977.
Description:
This research project was initiated with the primary objective of improving the commonly used COD test by the use of ferrate (VI) ion as an alternate or preliminary oxidant. The oxidation of NH3 and more general oxidation of organic compounds was desired. A secondary objective was the improved understanding of the mechanism of ferrate oxidations in dilute aqueous solutions. The oxidation kinetics of water (phosphate-borate buffer) by ferrate ion were studied spectrophotometrically and by oxygen evolution measurements. The kinetics of ferrate oxidation of methanol, formic acid, ethanol, acetaldehyde, acetic acid, NTA, IDA, glycine, glyoxalic acid, oxalic acid, triethylamine, diethylamine and piperidine were examined and are described. The dichromate COD analysis was carried out on several samples, including phenol, lactic acid and sewage from the Lincoln, Nebraska sewage treatment facility. COD analysis was also carried out on sewage samples after prior treatment with potassium ferrate at pH 9. There was evidence that the ferrate ion actually labilized organic materials originally refractory to the dichromate COD method but the oxidation of water (possibly catalyzed by sewage components) is too rapid to insure that the ferrate reacts quantitatively with the solute molecules. It is concluded, therefore, that the COD test cannot be improved significantly by the incorporation of ferrate (VI) ion as an oxidant.