In Situ Generation of Hydroxyl Radicals Using UV Light and TiO2 Photocatalysts on Quartz Felt

As water scarcity continues to become a growing concern, it is imperative that water purification technologies improve. Current best methods, such as advanced oxidative processes (AOPs), can be highly effective against targeted contaminants, but often require chemical additives (e.g. chlorine, peroxide, ozone) which increase costs and may lead to the formation of undesirable byproducts. Immobilized photocatalysts with strong light absorption, chemical stability, and high surface area could greatly reduce the need for oxidant feedstocks and improve the affordability of UV-AOPs. In this study, titania-based photocatalysts immobilized on quartz-fiber felt are used for UV-driven water treatment. Our mesoporous TiO2 and macroporous quartz felt yield a high surface area beneficial for mass transport, and optimal optical path length for UV light (250-400nm). Au nanoparticles can be added to the titania to increase the generation of reactive oxygen species (ROS) and provide alternative reaction pathways for degrading contaminants. Long term stability (>24 hour) to degrade model contaminants was tested under UVA LEDs and germicidal UVC lamps. Our photocatalysts produce >100 μM *OH in 20 seconds in a flow reactor and achieve an Electrical Energy per Order (EEO) of <0.6 for the degradation of Rhodamine B. This technology has the potential to be scaled up and integrated into current water purification systems to increase efficiency.