(56d) Chemical-Free Water Treatment with Immobilized Dual-Porous Photocatalyst

Advanced oxidative processes (AOPs), can be highly effective against a broad range of waterborne contaminants, but often require chemical additives (e.g. chlorine, peroxide, ozone) which increase costs and may lead to the formation of undesirable disinfection byproducts. The use of 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 AOPs.

Here, we report on the fabrication and characterization of photocatalysts immobilized on high-surface area supports for UV-driven water treatment. Our supported photocatalyst is mesoporous which, combined with the macroporous (Φ >0.95) support, yields a high surface area beneficial for mass transport. By using UV transparent supports, we maximize the photon management in our reactor.

We test the long-term stability and efficacy of our supported photocatalysts to degrade model contaminants under illumination from both UV-A LEDs and germicidal UV-C lamps. Our immobilized photocatalysts produce >100 μM *OH in 20 seconds in a flow reactor and achieve an Electrical Energy per Order (EE_O) of <0.6 for the degradation of Rhodamine B. We also examine the impact of water quality (pH, TOC, scavengers) and propose mechanisms for pollutant breakdown. Lastly, we will discuss the reactor design and relevant transport conditions for our supported photocatalysts, and the improvements necessary to scale our material for practical applications.