Integrated Photocatalytic Filtration Array for Indoor Air Quality Control

• Published in: Environmental science & technology Vol. 44; no. 14; pp. 5558 - 5563
• Main Authors: Denny, Frans, Permana, Eric, Scott, Jason, Wang, Jing, Pui, David Y. H, Amal, Rose
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.07.2010
• Subjects: Aerosols; Air Pollutants - chemistry; Air Pollution, Indoor; Applied sciences; Catalysis; Exact sciences and technology; Filters; Filtration - instrumentation; Filtration - methods; Indoor air quality; Integration; Light; Light emitting diodes; Outdoor air quality; Photocatalysis; Photochemistry - instrumentation; Photochemistry - methods; Photodegradation; Pollution; Remediation and Control Technologies; Ultraviolet radiation; Ventilation; Carbon compound; Filtration; Pollutant behavior; Photocatalysis; Carbon dioxide; Air quality; Hybrid system; Ultraviolet radiation; Mineralization; Aerosol generator; Quality control; Surface water; Indoor pollution; Diode array; Ventilation; Stream; Kinetics; Titanium oxide; Performance; Catalyst; Organic compounds; Photochemical degradation
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es100421u

Photocatalytic and filtration technologies were integrated to develop a hybrid system capable of removing and oxidizing organic pollutants from an air stream. A fluidized bed aerosol generator (FBAG) was adapted to prepare TiO2-loaded ventilation filters for the photodegradation of gas phase ethanol. Compared to a manually loaded filter, the ethanol photodegradation rate constant for the FBAG coated filter increased by 361%. Additionally, the presence of the photogenerated intermediate product, acetaldehyde, was reduced and the time for mineralization to CO2 was accelerated. These improvements were attributed to the FBAG system providing a more uniform distribution of TiO2 particles across the filter surface leading to greater accessibility by the UV light. A dual-UV-lamp system, as opposed to a single-lamp system, enhanced photocatalytic filter performance demonstrating the importance of high light irradiance and light distribution across the filter surface. Substituting the blacklight blue lamps with a UV-light-emitting-diode (UV-LED) array led to further improvement as well as suppressed the electrical energy per order (EE/O) by a factor of 6. These improvements derived from the more uniform distribution of light irradiance as well as the higher efficiency of UV-LEDs in converting electrical energy to photons.