[Synergy effect of dissolved oxygen in photodegradation of propisochlor in aqueous solution].

The synergetic effect of dissolved oxygen (DO) in the photodegradation of propisochlor aqueous solution was investigated in the presence of UV. With the increase of dissolved oxygen concentration, from 0 to 7.5 mg/L, photodegradation of propisochlor was accelerated. After the concentration of 7.5 mg/L, the rate and efficiency of photodegradation stopped increasing and began to decrease when the concentration became higher. During the photolysis process, dissolved oxygen was consumed. It suggested that the oxygen took an active part in the photolysis. It was found by analysis that the pohtolysis products under different dissolved oxygen concentrations were almost the same, but the production of several products was different. Singlet oxygen (1O2) as the resonance intermediate in the photolysis systems was confirmed by electron spin resonance spin trapping experiments.