DEGRADATION PHOTOINDUCED BY FE(III) - METHOD OF ALKYLPHENOL ETHOXYLATES REMOVAL IN WATER

The photoinduced degradation of an alkylphenol ethoxylate (APE) (Igepa l CA 520) by Fe(lll) in aqueous solution has been investigated. A comp lete characterization of the commercial product showed the presence of a mixture of compounds with various ethoxy and alkyl chain lengths. T he photodegradation study was carried out with the major fraction of e thoxymers having an alkyl chain length of 8 carbon atoms and n ethoxy units E (C8PhEn). We have demonstrated that the Fell II) sensitized de gradation of this fraction occurs efficiently both at 365 nm and under sunlight. The rate of degradation depends on the concentration of Fe( OH)(2+), the most photoreactive species in terms of (OH)-O-. radical f ormation. The primary step of the decomposition of Igepal involves the hydrogen abstraction on one carbon of the ethoxy chain. The shortenin g of the ethoxylated chain all along the degradation process was obser ved. The identified photoproducts are aldehyde ethoxylates, formate et hoxylates, and octylphenol that is a persistent product in the environ ment. The mechanism only involves attack by (OH)-O-. radicals that are formed through photolysis of Fe(OH)2+. For prolonged irradiations, th e total degradation of Igepal CA 520 and of the photoproducts is obtai ned. Consequently, the degradation photoinduced by Fe(lll) could be an efficient method of APEs removal in water.