determination of sulfaclozine degradation pathway on tio2 suspensions based on the role of different ros.

SSCI-VIDE+ATARI+LIS:JMC:CFE:LFIInternational audienceThe photocatalytic removal of the antibiotic sulfaclozine (SCL) in aqueous suspensions of TiO2 under UV light was investigated and a complete degradation of 88 µM of sulfaclozine was obtained after 60 min. The addition of reactive oxygen species (ROS) scavengers (isopropanol, methanol and KI) at different concentrations allowed us to understand the assessment of the different ROSs in sulfaclozine degradation.The rate constant of the reaction between sulfaclozine and â¢OH radicals was determined by a competitive kinetic method and a value of (7.2Ã109 M-1 s-1) was found.HPLC/DAD and LC-MS/MS were used to follow the kinetics of appearance and disappearance of sulfaclozine as well as its intermediates. Twelve main photoproducts were identified from the photocatalytic degradation of sulfaclozine on TiO2 suspensions by using LC-MS/MS. The comparison of the evolution of these intermediates with and without the addition of methanol showed that the quantity of 8 intermediates was decreased in the presence of methanol, for three of them the same amount was obtained while an increase was observed for one of them. Based on the identified intermediates, and the effect of ROS scavengers, a tentative degradation pathway for the photocatalytic degradation of sulfaclozine was proposed. In addition, total organic carbon (TOC) was examined