Advanced oxidation degradation kinetics as a function of ultraviolet LED duty cycle
| Autor: | LeeAnn Racz, Rebecca Phillips, Michael Spencer, Kelsey L Duckworth, Michael E. Miller, Michael R. Grimaila, Matthew L. Magnuson, Christopher Bates, Catherine B. Almquist, Stuart A. Willison |
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| Rok vydání: | 2015 |
| Předmět: |
Environmental Engineering
Materials science Ultraviolet Rays Continuous operation medicine.disease_cause Waste Disposal Fluid law.invention chemistry.chemical_compound law Oxidizing agent medicine Hydrogen peroxide Water Science and Technology Photolysis Environmental engineering Hydrogen Peroxide Oxidants Methylene Blue Kinetics chemistry Chemical engineering Duty cycle Degradation (geology) Oxidation-Reduction Water Pollutants Chemical Ultraviolet Waste disposal Light-emitting diode |
| Zdroj: | Water Science and Technology. 71:1375-1381 |
| ISSN: | 1996-9732 0273-1223 |
| Popis: | Ultraviolet (UV) light emitting diodes (LEDs) may be a viable option as a UV light source for advanced oxidation processes (AOPs) utilizing photocatalysts or oxidizing agents such as hydrogen peroxide. The effect of UV-LED duty cycle, expressed as the percentage of time the LED is powered, was investigated in an AOP with hydrogen peroxide, using methylene blue (MB) to assess contaminant degradation. The UV-LED AOP degraded the MB at all duty cycles. However, adsorption of MB onto the LED emitting surface caused a linear decline in reactor performance over time. With regard to the effect of duty cycle, the observed rate constant of MB degradation, after being adjusted to account for the duty cycle, was greater for 5 and 10% duty cycles than higher duty cycles, providing a value approximately 160% higher at 5% duty cycle than continuous operation. This increase in adjusted rate constant at low duty cycles, as well as contaminant fouling of the LED surface, may impact design and operational considerations for pulsed UV-LED AOP systems. |
| Databáze: | OpenAIRE |
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