Degradation Pathway of the Photochemical Oxidation of Ethylenediaminetetraacetate (EDTA) in the UV/H2O2-process

✍ Scribed by Sörensen, M. ;Zurell, S. ;Frimmel, F. H.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 386 KB
• Volume: 26
• Category: Article
• ISSN: 0323-4320
• DOI: 10.1002/(sici)1521-401x(199803)26:2<109::aid-aheh109>3.0.co;2-c

✦ Synopsis

The degradation pathway for the oxidation of EDTA in the UV/H 2 O 2 -process was investigated. In absence of iron ions, the mineralization of EDTA is dominated by the reaction of the HO-radicals generated by the photolysis of H 2 O 2 . The organic degradation products iminodiacetate (IMDA), glycinate, oxamate, glyoxylate, oxalate and formate, and the inorganic degradation products carbon dioxide, ammonia, nitrate, nitrite, and cyanate were found. In the presence of iron ions, photolytic decarboxylation processes inside the complex get an important role during degradation, and the organic degradation products ethylenediaminetriacetate (ED3A), ethylenediaminediacetate (EDDA), ethylenediaminemonoacetate (EDMA) were also found. By combining product studies with balances of carbon and nitrogen, the degradation pathway in the UV/H 2 O 2 -process could be elucidated. The degradation of EDTA was fast (k deg = 0.012 s -1 ), and no toxic degradation products were identified. Therefore, the process is well suited for the elimination of EDTA in water treatment.