Photocatalytic Treatment of Bioaerosols: Impact of the Reactor Design

Abstract

Comparing the UV-A photocatalytic treatment of bioaerosols contaminated with different airborne microorganisms such as L. pneumophila bacteria, T2 bacteriophage viruses and B. atrophaeus bacterial spores, pointed out a decontamination sensitivity following the bacteria > virus > bacterial spore ranking order, differing from that obtained for liquid-phase or surface UV-A photocatalytic disinfection. First-principles CFD investigation applied to a model annular photoreactor evidenced that larger the microorganism size, higher the hit probability with the photocatalytic surfaces. Applied to a commercial photocatalytic purifier case-study, the CFD calculations showed that the performances of the studied purifier could strongly benefit from rational reactor design engineering. The results obtained highlighted the required necessity to specifically investigate the removal of airborne microorganisms in terms of reactor design, and not to simply transpose the results obtained from studies performed toward chemical pollutants, especially for a successful commercial implementation of air decontamination photoreactors. This illustrated the importance of the aerodynamics in air decontamination, directly resulting from the microorganism morphology.

Comparison of Infectious Agents Susceptibility to Photocatalytic Effects of Nanosized Titanium and Zinc Oxides: A Practical Approach

“…Despite the common opinion of the relatively high virus susceptibility to AOPs (Fig. 1 ), Josset et al [ 57 ] and Zhao et al [ 58 ] suggest a higher (compared to bacteria) resistance of viruses to photocatalytic processes.…”

Assessing microbial decontamination of indoor air with particular focus on human pathogenic viruses

“…23 Inactivation of microbial agents in indoor air has been addressed using photocatalysis as a function of the oxidizing power of ultraviolet radiations A (UVA)-irradiated semiconductors. 40,41 UV treatment involves the use of a photoreactor, some of them being commercially available, in which air is drawn through and particles impact on the photocatalytic surface. The efficiency of air decontamination varies with aerosol size because smaller aerosols are less likely to contact the decontamination surface.…”

“…The efficiency of air decontamination varies with aerosol size because smaller aerosols are less likely to contact the decontamination surface. 40 UV lamps have traditionally been applied to reduce aerosol transmission of Mycobacterium tuberculosis, and the potential for UV to kill a variety of vegetative cells in air is not without merit. UV irradiation has shown efficacy against certain fungal spores, such as those of Aspergillus spp, and for removal or inactivation of microbial aerosols at significant rates; however, this technology was not at the time of the study applied on a routine basis during outbreaks.…”

Magnetic Nano-photocatalysts: Preparation, Structure, and Application

“…Fifth, it is inexpensive (Bhatkhande et al 2001 ) . Furthermore, photocatalysts can oxidize ammonia, another prevalent environmental problem in the wastewater, to nitrogen gas (Besten and Qasim 1964 ;Lee et al 2002 ;Pretzer et al 2008 ;Kolinko and Kozlov 2009 ) , and destroy bacterial cells (Wakamura et al 2003 ) , viruses (Josset et al 2010 ) , cancer cells (Fujishima et al 2000 ) , and so on. Thus, the photocatalytic degradation of environmental pollutants is an interesting topic to study.…”