Photocatalytic ceramic membrane: Effect of the illumination intensity and distribution

The principles and application of heterogeneous photocatalytic processes have gained wide attention, especially to the effectiveness of the process. In this work a mono and a multi-LED lamp are used to study the impact of the UV light intensity and distribution on the semiconductor surface during the degradation of organic compounds in water. A well-defined scan of the electromagnetic radiation profile on the surface of the membrane was obtained and evaluated. Comparing two lamp configurations with a total photon flux of 210 W.m-2 and using a filtration rate of 9.7 L.m-2.h-1, resulted in 20 % more degradation for the most homogeneous light distribution. Furthermore, the reaction rate relation to the photon flux was also studied, with a surface reaction model that includes possible mass transfer limitations. The surface reaction constant increased linearly with the irradiation intensity for the complete studied range [50 to 550 W.m-2] for the most homogeneous illumination distribution. A less uniform distribution resulted in a less than proportional reaction rate constant with respect to the incident photon flux between 100 and 210 W.m-2. This work adds valuable information to the photocatalysis field to improve the light efficiency in a photoreactor to enhance the degradation of pollutants.