Process Safety and Environmental Protection, Vol.135, 265-272, 2020
Gas-phase aromatic compounds degradation by a partially TiO2 coated photoreactor assisted with ozone
Heterogeneous photocatalysis with TiO2 have been studied for VOCs degradation; however, aromatic VOCs degradation lead TiO2 deactivation. The objective of this study was to degrade aromatic VOCs by heterogeneous photocatalysis avoiding TiO2 deactivation. The experiments were conducted using a UV-C lamp (254 nm), relatively humidity (RH - 26-60 %), and ozone (03 - 2.38 to 5.35 %). Due to O-3 addition, it was necessary to have uncoated regions in the quartz tube around the lamp to allow UV photons to reach the gas bulk and generate radicals from O-3. Different quartz tube coating fractions were tested to analyze its influence on VOCs degradation. The highest toluene degradation was 99.2 % for the reactor with 90 % of coating, 3.4 % of O-3, space time of 123 s, and RH of 26 %. It was observed RH greater than 26 % affected the degradation achieved. Ozone addition allowed TiO2 use for 77 h avoiding early catalyst deactivation. Besides that, the requirement of uncoated regions indicated that VOC oxidative reactions occur both on solid and gas phases. This suggested that the addition of O-3 combined with the reactor configuration is a promising alternative for aromatic compound degradation by heterogeneous photocatalysis. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.