The photochemical reactions of the organochlorine pesticide DOT in aqueous solutions containing nonionic surfactant micelles (Brij 35, Brij 52, and Brij 72) were investigated and modeled. All photolytic experiments were conducted in a RayonetRPR-200 merry-go-round photoreactor using a 253.7-nm mercury monochromatic ultraviolet (UV) lamps. Pseudo-first-order decay through photo-dechlorination was observed to be the dominant reaction pathway for DDT photodecay. The primary photoproducts include lesser chlorinated compounds (DDE and DDD) and hydrogen chloride. The photodechlorination of DDT involves two stages; the first is the fast aliphatic chlorine reduction, followed by a slow aromatic chlorine reduction. The photodecay rates of DDT weredoubled in the Brij 52 micellar solution compared to that in water alone. A firstorder parallel/consecutive model was developed and found useful to predict the photodecay of DDT and the generation of DDE/DDD in the micellar/aqueous system.
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