Efficacy of photocatalytic HEPA filter on microorganism removal

Chuaybamroong, Paradee; Chotigawin, R.; Supothina, Sitthisuntorn; Sribenjalux, Pipat; Larpkiattaworn, Siriporn; Wu, Chang‐Yu

doi:10.1111/j.1600-0668.2010.00651.x

Cited by 83 publications

(72 citation statements)

References 28 publications

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“…1) were cut to a size of 20 × 20 cm. Before coating, the high grade filter was pre-treated to remove water-resistance by washing with 0.08 M sodium dodecyl sulfate, drying at room temperature for 24 hr and desiccating for at least 2 hr (Chuaybamroong et al, 2010).…”

Section: Tio 2 -Coating Proceduresmentioning

confidence: 99%

Enhancement of Air Filter with TiO2 Photocatalysis for Mycobacterium Tuberculosis Removal

Thunyasirinon

Sribenjalux

Supothina

2015

Aerosol Air Qual. Res.

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HEPA filter is normally recommended for removal of Mycobacterium tuberculosis from the airstream. Due to its high cost, a cheaper air-filter substitution is proposed in this study. Both low-and high-grade glass fiber air filters were coated with 5% TiO 2 using either polyethylene glycol (PEG), Silane (Si-69), or DURAMAX (D-3005) as a binder. The coated filter was placed in a test duct and irradiated with UVA at an intensity of 4.85 ± 0.41 mW/cm 2 to investigate photocatalysis for M. tuberculosis. The effects of dark and light conditions as well as initial exposure to UVA on bacterial removal were studied. Silver-doped and iron-doped TiO 2 at different concentrations were also tested using face velocities of 0.1 and 1 m/s and humidity levels of 50 ± 10% and 70 ± 10% RH.The most appropriate binder for coating TiO 2 onto filters was 3% D3005. Using 0.1% metal-doping, 100% removal efficiencies were found. Dark/light conditions affected the hydrophobic/hydrophilic properties of TiO 2 -coated filters and the removal efficiencies. The removal rate could be increased by extending the warm up period of the lamps. When the face velocity was increased, the removal efficiency dropped in both filters. Similarly, high humidity adversely affected the removal efficiency, particularly with the coated high-grade air filter.

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Section: Tio 2 -Coating Proceduresmentioning

confidence: 99%

Enhancement of Air Filter with TiO2 Photocatalysis for Mycobacterium Tuberculosis Removal

Thunyasirinon

Sribenjalux

Supothina

2015

Aerosol Air Qual. Res.

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“…Baking at 50°C for 30 min after coating with 5% TiO 2 not only yielded higher loading than baking at 100°C for 30 min, but these air filters also achieved greater strength, resulting in a more practical use for air treatment. Moreover, this baking method after coating produced better energy-saving air filters than the previous studies 6,16,17 . When comparing 2% and 5% TiO 2 loading after baking at 50°C for 30 min, the highest loading was achieved by coating with 5% TiO 2 .…”

Section: Discussionmentioning

confidence: 59%

“…This result was consistent with a previous study 20 which found that this chemical surface treatment provided not only increased roughness of the fibre surfaces but also increased the interaction between the TiO 2 and the substrate. According to the previous investigations 16,17 , using 0.08 M SDS could reduce the water resistance of the fibres of the pretreated HEPA filters, which were the same type of HEPA filter used in this study. In the present experiment, some fibres and other wastes were found in the SDS suspension, and these wastes also changed the colour of the suspension.…”

Section: Discussionmentioning

confidence: 66%

“…Few studies have reported on high-efficiency particulate air (HEPA) or fibre glass filters coated with a TiO 2 photocatalyst, and the effect of varying surface pretreatment methods, TiO 2 suspensions, and baking temperatures in the preparation of the coated filters 16,17 . The surface morphology and physical properties, as well as removal of xylene, which was selected as a representative gaseous pollutant for testing the effectiveness of the combination between an ESF pack and a photocatalytic air filter, are essentially unknown for these coated filters (PCO reaction) within an electromagnetic field.…”

Section: Introductionmentioning

confidence: 99%

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Preparation of a TiO2-coated photocatalytic air filter for use with an electrostatic air filter pack for xylene removal

Limmongkon¹,

Johns²,

Charerntanyarak³

2013

ScienceAsia

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This study evaluated surface morphology, mechanical stability, and the effectiveness for xylene removal of coated fibre glass filters and coated high-efficiency particulate air (HEPA) filters for use with an electrostatic air filter pack (ESF pack). Different surface pretreatment methods, two TiO2 coating suspensions with different amounts of TiO2 and additive substances, varied baking temperatures, and various combinations between an ESF pack and a coated air filter were investigated. This investigation found that washing the substrates with 0.08 M sodium dodecyl sulphate and 0.01 M sodium fluoride before coating with 5% TiO2 suspension and then baking at 50°C for 30 min after coating could yield the highest loadings of 285 g/m 2 for the fibre glass filters and 182 g/m 2 for the HEPA filters. Examination of these filters revealed that the TiO2 particles were agglomerated and stuck to the fibres as well, resulting in less loading loss. The highest removal efficiency of xylene (in 400-800 ppb) ranged from 41-49% when using a combination of one HEPA filter coated with 5% TiO2 suspension together with four layers of ESF filters at an air flow rate of 10 m 3 /min and 45 ± 5% RH. The suitable preparation of photocatalytic air filters is of great importance for their practical use, ensuring the stability of the coating and resulting in a product that is safe for human health and friendly to the environment.

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“…Typical catalysts include TiO 2 , WO 3 , ZnS, while the photocatalytic reaction can be achieved with fluorescent or UV light. Combination PCO/HEPA filter units have been proposed to purify the indoor air [36]. Pathogens have been observed to be readily destroyed by PCO units [37], however most research into PCO cleaner for indoor air purification have been trialled in laboratory settings, and there is little information available on its efficiency in a biodefense setting environment.…”

mentioning

confidence: 99%

The Role of Protection Measures and their Interaction in Determining Building Vulnerability and Resilience to Bioterrorism

Taylor¹,

Margaritis²,

Nasir³

et al. 2013

J Bioterror Biodef

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Understanding the risk presented to buildings by bioterrorism has been a topic of research interest in recent years. Risk assessment methodologies and guidelines for the protection of buildings have been developed by a number of researchers, but it remains difficult to quantify the vulnerability and resilience of a building. It is an important issue from both biosecurity investment and operation point of view because different measures have different cost and operation implications. This paper reviews existing risk assessment methodologies, introduces a novel framework for classifying protection measures, and determines the inter-relation of the framework components and building vulnerability and resilience using a fault tree analysis within a biosecurity network system. Future work will develop weighting values for the different protection measures within the framework, allowing for the calculation of bioterrorism resilience of existing buildings, and to provide a decision making guide for building architects, builders, and managers for new and retrofitted buildings. The physical decay of BWA in the indoor environment refers to the loss attributable to physical factors such as unrestricted diffusion, surface impaction, and fall-out. Unrestricted diffusion allows the movement of aerosolized particles out of the zone where the pathogen was released into other areas within the building, or the external environment. This dilutes the concentration of the particle in the indoor air, but can also lead to the spread of the pathogen to areas of the building not directly targeted. Surface impaction refers to the attachment of contaminants to surfaces, while fall out refers to the deposition of the contaminant particles on surfaces due to gravity. Physical decay does not necessarily eliminate the threat, but may remove it from the indoor air, although the risk of re-suspension can remain.The biological decay of BWA within the built environment depends on the type of pathogen, and the surrounding environmental conditions. Potential pathogens used in bioterrorism can exhibit a range of survival times in the environment. The persistence of pathogens is dependent on environmental conditions, including the temperature and relative humidity of the indoor environment and solar radiation levels [3]. Fungi and some bacterial species, for example Anthrax, can form spores, allowing them to survive desiccation and remain viable for years. The nature of the BWA and the means of delivery of the contaminant to the building will dictate the threat and the consequences of an attack. Threat analysis for buildingsA successful bioattack on a building will be a product of a number of factors, including the terrorists' resources, capabilities, and decisions, actions by other individuals and/or groups, and the buildings resilience. Assessing terrorism risk in specific buildings is often considered to be a combination of the threat of an attack, the vulnerability to the attack, and the expected consequences of theattack. Risk threat vuln...

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Efficacy of photocatalytic HEPA filter on microorganism removal

Cited by 83 publications

References 28 publications

Enhancement of Air Filter with TiO2 Photocatalysis for Mycobacterium Tuberculosis Removal

Enhancement of Air Filter with TiO2 Photocatalysis for Mycobacterium Tuberculosis Removal

Preparation of a TiO2-coated photocatalytic air filter for use with an electrostatic air filter pack for xylene removal

The Role of Protection Measures and their Interaction in Determining Building Vulnerability and Resilience to Bioterrorism

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