Solar-Induced Removal of Benzophenones Using TiO₂ Heterogeneous Photocatalysis at Lab and Pilot Scale

This work presents the main results regarding the use of solar heterogeneous photocatalysis with TiO₂ on the removal of Benzophenone-1 and Benzophenone-2 (BP1 and BP2) in aqueous samples at lab and pilot scale. BP1 and BP2 are two UV-filters that have been classified as potential endocrine disruptors, and their presence in water has been reported by different researches. Experiments were conducted at lab scale using simulated sunlight radiation, while at pilot scale a solar compound cylinder-parabolic (CCP) collector and direct sunlight were employed. Effects of catalyst concentration and solution pH on contaminants elimination were assessed. Pollutants were completely removed at lab conditions in just 60 min of reaction, while under pilot scale tests elimination was around 90.0% in 360 min. Mineralization of treated samples was around 60%. In general, it was found that the photo-generation of hydroxyl (HO·) radicals contributes to BP1 and BP2 removal, and that higher doses of TiO₂ could have an inhibitory effect. Additionally, presence of some inorganic ions on the aqueous matrix (drinking water) used in the pilot-scale tests would be associated to a reduction on the extent of pollutants degradation, which together with aspects such as the type of reactor and the atmospheric and climate conditions would limit the process efficiency in comparison with results at lab-scale experiments.