Recent Development of VUV-Based Processes for Air Pollutant Degradation

Huang, Haibao; Lu, Haoxian; Huang, Huiling; Wang, Lei; Zhang, Jieni; Leung, Dennis Y.C.

doi:10.3389/fenvs.2016.00017

Cited by 25 publications

(6 citation statements)

References 94 publications

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“…Firstly, only the gas phase reaction was explored to study the role of VUV light in VUV photocatalysis. The gas phase reaction under VUV light involves light of 185 nm wavelength, light of 254 nm wavelength, ozone oxidation, water ionization, and subsequent attack of reactive oxidant species (Huang et al 2016) since commercial VUV lamps generally emit both 185 nm and 254 nm wavelength components, with photon energies of 6.70 eV and 4.88 eV, respectively (Zhang et al 2004). Light of 185 nm wavelength and residual ozone are both typical of the VUV photolysis process.…”

Section: Methodsmentioning

confidence: 99%

Inactivation of airborne viruses using vacuum ultraviolet photocatalysis for a flow-through indoor air purifier with short irradiation time

Kim

Jang

2018

Aerosol Science and Technology

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Many ultraviolet (UV)-based disinfection methods have been developed; however, these methods usually use the recirculating mode or need long irradiation periods due to its low photon energy. Vacuum UV (VUV) was recently found to be a promising light source, despite its ozone generation. In this study, we investigated photocatalysis reactions by VUV with short irradiation times (0.004-0.125s) for simultaneously inactivating airborne MS2 viruses and degrading the generated ozone toward a flow-through air disinfection system with high flow-rates. We developed three effective shapes for the catalyst frame: 2mm and 5mm pleated, and spiral-type Pd-TiO 2 catalysts. The 2mm pleated Pd-TiO 2 /VUV photocatalyst exhibited the highest activity ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 for simultaneous MS2 inactivation and ozone degradation, and the catalytic activity was effective regardless of relative humidity. Considering the gas phase and catalyst surface effects, and the natural inactivation of VUV-irradiated but live MS2 viruses, the 2mm pleated PdTiO 2 /VUV and succeeding UV photocatalysis showed more than 90% in the overall inactivation efficiency with residual ozone of 35ppb at an irradiation time of 0.009s (flow-rate: 33 l/min). In contrast, most UV-based purifiers take longer times for disinfection. This system has the potential for an alternative to conventional UV-based air purifiers.

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Section: Methodsmentioning

confidence: 99%

Inactivation of airborne viruses using vacuum ultraviolet photocatalysis for a flow-through indoor air purifier with short irradiation time

Kim

Jang

2018

Aerosol Science and Technology

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“…[ 69 ] The key processes used in the technique are direct photolysis, photocatalysis, and ozone oxidation, which is formed by the byproduct ozone and may effectively destroy organic molecules. [ 143 ]…”

Section: Strategies For Improving Photocatalytic Efficiency Aiming At...mentioning

confidence: 99%

A review of prospects and challenges of photocatalytic decomposition of volatile organic compounds (VOCs) under humid environment

Masresha,

Jabasingh,

Kebede

et al. 2023

Can J Chem Eng

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Volatile organic compounds (VOCs) are harmful for humans and the surrounding ecosystem. Emissions from these pollutants have caused a significant reduction in air quality, which has an effect on people's health. Alkanes, alkenes, alcohols, aromatics, and other VOC pollutants have all been broken down by TiO2 photocatalytic processes. Due to several operating inefficiencies and deactivation issues in humid environments, the practical application of photocatalysis has not been realized on a broader scale. The effectiveness of photo‐oxidation of VOCs is impacted by a variety of environmental conditions. In the photocatalytic oxidation of the VOCs, relative humidity (RH) is critical. Therefore, it is important to review the recent findings on how humidity affects the photocatalytic breakdown of VOCs in air. To satisfy this need, this work provides a critical review of the related literature with focus on the fundamentals of photocatalysis, photocatalytic degradation of air pollutants, and the influence of humidity on the photocatalytic process degradation for selected air pollutants. It also highlights the kinetic models and typical photocatalytic reactor and supports for VOC removal.

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“…It can be assumed that the degradation rate of photolysis is faster when the wavelength of the photon is shorter than the maximum absorption wavelength of the substance. Furthermore, VUV at 185 nm can produce energetic photons, leading to mainly direct photolysis of target compounds as well as indirect decomposition through the formation of hydroxyl radicals and other strong oxidants, such as ozone and hydrogen peroxide [23].…”

Section: Effects Of the Uv Light Source And Tio 2 Photocatalysis On D...mentioning

confidence: 99%

“…However, commercially available VUV lamps have a main output at 254 nm with only a small amount (<10% of the total intensity of irradiation) at 185 nm. Therefore, semiconductors, such as titanium dioxide (TiO 2 ), can be used to produce more hydroxyl radicals via photocatalysis [23]. TiO 2 is a well-known photocatalyst, because of the advantages of a superior photocatalytic oxidation ability and optical and electronic properties [24].…”

Section: Introductionmentioning

confidence: 99%

Photolysis and TiO2 Photocatalytic Treatment under UVC/VUV Irradiation for Simultaneous Degradation of Pesticides and Microorganisms

et al. 2020

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Efficiencies of various treatments for UVC photolysis (ultraviolet light-C at 254 nm), VUV photolysis (vacuum ultraviolet light at 254 nm and 185 nm), UVC-assisted titanium dioxide photocatalysis (UVC-TiO2), and VUV-assisted titanium dioxide photocatalysis (VUV-TiO2) were investigated for the degradation of pesticides including pyraclostrobin, boscalid, fludioxonil, and azoxystrobin and inactivation of microorganisms Escherichia coli K12 as a surrogate for E. coli O157:H7 and Saccharomyces cerevisiae in aqueous solutions and on the surface of fresh cut carrots. The degradation efficiencies of VUV were higher than for UVC on pesticides in aqueous solutions. However, there was no significant difference between degradation efficiencies for UVC and UVC-TiO2 treatments, and between VUV and VUV-TiO2 treatments. UVC, VUV, UVC-TiO2, and VUV-TiO2 showed similar inactivation effects against E. coli K12 and S. cerevisiae in aqueous solutions. The combined use of UVC and VUV treatments (combined UV) and combined use of UVC-TiO2 and VUV-TiO2 treatments (combined UV-TiO2) showed higher efficiencies (72–94% removal) for the removal of residual pesticides on fresh cut carrots than bubble water washing (53–73% removal). However, there was no significant difference in removal efficiency between combined UV and combined UV-TiO2 treatments. For E. coli K12 and S. cerevisiae on fresh cut carrots, the combined UV-TiO2 treatment (1.5 log and 1.6 log reduction, respectively) showed slightly higher inactivation effects than combined UV (1.3 log and 1.2 log reduction, respectively). Photolysis and TiO2 photocatalytic treatments under UV irradiation, including VUV as a light source, showed potential for the simultaneous degradation of pesticides and microorganisms as a non-chemical and residue-free technique for surface disinfection of fresh produce.

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Recent Development of VUV-Based Processes for Air Pollutant Degradation

Cited by 25 publications

References 94 publications

Inactivation of airborne viruses using vacuum ultraviolet photocatalysis for a flow-through indoor air purifier with short irradiation time

Inactivation of airborne viruses using vacuum ultraviolet photocatalysis for a flow-through indoor air purifier with short irradiation time

A review of prospects and challenges of photocatalytic decomposition of volatile organic compounds (VOCs) under humid environment

Photolysis and TiO2 Photocatalytic Treatment under UVC/VUV Irradiation for Simultaneous Degradation of Pesticides and Microorganisms

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