Incomplete oxidation of ethylenediaminetetraacetic acid in chemical oxygen demand analysis
Ethylenediaminetetraacetic acid (EDTA) was found to incompletely oxidize in chemical oxygen demand (COD) analysis, leading to incorrect COD values for water samples containing relatively large amounts of EDTA. The degree of oxidation depended on the oxidant used, its concentration, and the length of...
| Veröffentlicht in: | Water environment research : a research publication of the Water Environment Federation. - 1998. - 79(2007), 9 vom: 15. Sept., Seite 1043-9 |
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| Weitere Verfasser: | , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2007
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| Zugriff auf das übergeordnete Werk: | Water environment research : a research publication of the Water Environment Federation |
| Schlagworte: | Journal Article Chelating Agents Edetic Acid 9G34HU7RV0 Oxygen S88TT14065 |
| Zusammenfassung: | Ethylenediaminetetraacetic acid (EDTA) was found to incompletely oxidize in chemical oxygen demand (COD) analysis, leading to incorrect COD values for water samples containing relatively large amounts of EDTA. The degree of oxidation depended on the oxidant used, its concentration, and the length of digestion. The COD concentrations measured using COD vials with a potassium dichromate concentration of 0.10 N (after dilution by sample and sulfuric acid) were near theoretical oxygen demand values. However, COD measured with dichromate concentrations of 0.010 N and 0.0022 N were 30 to 40% lower than theoretical oxygen demand values. Similarly, lower COD values were observed with manganic sulfate as oxidant at 0.011 N. Extended digestion yielded somewhat higher COD values, suggesting incomplete and slower oxidation of EDTA, as a result of lower oxidant concentrations. For wastewater in which EDTA is a large fraction of COD, accurate COD measurement may not be achieved with methods using dichromate concentrations less than 0.1 N |
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| Beschreibung: | Date Completed 04.01.2008 Date Revised 23.09.2019 published: Print Citation Status MEDLINE |
| ISSN: | 1061-4303 |