Photocatalytic Nanowires‐Based Air Filter: Towards Reusable Protective Masks

Abstract

In the last couple decades, several viral outbreaks resulting in epidemics and pandemics with thousands of human causalities have been witnessed. The current Covid-19 outbreak represents an unprecedented crisis. In stopping the virus' spread, it is fundamental to have personal protective equipment and disinfected surfaces. Here, the development of a TiO 2 nanowires (TiO 2 NWs) based filter is reported, which it is believed will work extremely well for personal protective equipment (PPE), as well as for a new generation of air conditioners and air purifiers. Its efficiency relies on the photocatalytic generation of high levels of reactive oxygen species (ROS) upon UV illumination, and on a particularly high dielectric constant of TiO 2 , which is of paramount importance for enhanced wettability by the water droplets carrying the germs. The filter pore sizes can be tuned by processing TiO 2 NWs into filter paper. The kilogram-scale production capability of TiO 2 NWs gives credibility to its massive application potentials.

Antimicrobial TiO2 nanocomposite coatings for surfaces, dental and orthopaedic implants

“…A specialized reusable filter surface with photocatalytic TiO 2 nanowires (TiO 2 NWs) was developed to inactive the airborne pathogens [1] . TiO 2 NWs offered an improved photocatalytic efficiency owing to the high surface to volume ratio for ROSs generation [72] .…”

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Figure 8 (a) SEM image of TiO 2 NWs filter overlapped with schematic images of pathogens, (b) photocatalytic mechanism of ROSs generation on the humid TiO 2 NWs [1] . Reproduced with permission from [1] . Copyrights (2020), John Wiley and Sons

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“…The outbreak of various infectious diseases such as SARS-CoV, H1N1, and Ebola has resulted in a significant impact on the global economy and health systems [1] , [2] . SARS-CoV-2 is the most recent pandemic, caused by the human coronavirus [3] , [4] , [5] .…”

“…Compared to the normal sanitation procedures, durable photocatalytic coatings could hinder the reactivation of microbes and destroy them completely. The mobility of ROSs in air is normally higher and so it could effectively destroy airborne microbes [1] . Titanium dioxide or titania (TiO 2 ) is one of the best photocatalysts for commercial antimicrobial coatings owing to its low-cost, reactivity, stability, reusability, durability, biocompatibility, crystallinity, high surface area and corrosion resistance.…”

Advances in Facemasks during the COVID-19 Pandemic Era

“…This filter was easily sterilizable and reusable, and exhibited antiviral properties, thereby providing a potent preventative tool against the rapid transmission of SARS-CoV-2 during the pandemic. 148 …”