Industrial Chemistry
Open Access

Abstract

Degradation of boscalid (Bd) in aqueous solution was studied using different oxidation systems, including persulfate ion (PS), TiO2 (UT), N-TiO2(NT) and mixtures of UT/PS and NT/PS under sunlight irradiation, in addition to using heatactivated (50 or 80ºC) PS ions. NT had a higher percentage for Bd degradation than UT, which was explained by a higher surface area and a higher amount of anatase for NT. However, systems of NT/PS or UT/PS did not degrade Bd as much as PS alone under sunlight, which may have resulted from the interaction between the produced hydroxyl and sulfate radicals. Eventually, the highest Bd degradation was obtained by the activation of PS at 80ºC. On the other hand, degradation of Bd in aqueous solution containing MeOH by NT or UT was completely inhibited. MeOH is a scavenger for both hydroxyl radicals OH• and the positive hole of the activated catalysts. In addition, the PS system was more affected by MeOH presence than were the UT/PS and NT/PS systems. This result can be explained by the fact that i) MeOH scavenged further OH• than SO4•- and ii) more SO4•- was present for systems of UT/PS, especially for NT/PS, than PS. Therefore, NT/PS or UT/PS systems have a higher percentage of Bd degradation in aqueous solution containing MeOH than the PS system. Eventually, an analysis of Bd residues and the identification of its 7 basic intermediates were carried out using LC/MS/MS.

Biography

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