Figures & data
Figure 1. Effect of LED spacing and distance away from the LED (i.e., ½ D) on: (a) lateral irradiance uniformity and (b) radial irradiation uniformity.
Figure 2. (a) A 3-D model of the annular reactor shown with the LED light source and (b) the STC pellets used as the photocatalyst in the reactor (color figure available online).
Table 1. Comparison of test reactors
Figure 3. Schematic of the setup used for light source characterization, illustrating the effect of aperture size on the amount of photons from the adjacent LEDs entering the integrating sphere: (a) 12.7 mm diameter and (b) 31.8 mm diameter (color figure available online).
Figure 4. Illustration of the bench-scale PCO test bed employed to control the experimental parameters and monitoring the PCO process, objects are not to scale.
Figure 5. Spectra of the UV-A LEDs and fluorescent (F8T5) black lights.
Figure 6. Irradiance profiles of the LED assembly determined at I F = 100 mA: (a) lateral and radial profiles on the outer surface of the quartz sleeve (OD 28 mm) where the photocatalyst is located; (b) comparison between measured average and model-predicted irradiance.
Table 2. LED solder temperature (T s) and dice temperature (T j) as a function of I F
Figure 7. Time-course of the effluent composition during STC-catalyzed oxidation of ethanol in the (a) UV-A LED and (b) UV-A BLB reactors at the same irradiance of 4 mW cm−2. CO2 concentration was recorded every minute and was affected by the sample stream valve position.
Figure 8. A linear relationship between CO2 production and time during STC-catalyzed PCO of ethanol in both UV-A LED and BLB reactors, suggesting an zero-order reaction kinetics.
Table 3. Effluent composition and PCO efficiency at the pseudo-steady state from the BLB and LED reactors at the same irradiance
Figure 9. Effect of the LED average irradiance at the catalyst surface on: (a) reactor effluent composition, (b) ethanol removal, (c) ethanol mineralization, (d) PCO rate, and (e) photonic efficiency.
