A titanate nanowire mask that can eliminate pathogens

Date:
August 7, 2020
Source:
Ecole Polytechnique Fe'de'rale de Lausanne
Summary:
Researchers are working on a membrane made of titanium oxide
nanowires, similar in appearance to filter paper but with
antibacterial and antiviral properties. Their material works by
using the photocatalytic properties of titanium dioxide: when
exposed to ultraviolet radiation, the fibers convert resident
moisture into oxidizing agents such as hydrogen peroxide, which
have the ability to destroy pathogens.



FULL STORY ==========================================================================
As part of attempts to curtail the Covid-19 pandemic, paper masks
are increasingly being made mandatory. Their relative effectiveness
is no longer in question, but their widespread use has a number of
drawbacks. These include the environmental impact of disposable masks made
from layers of non-woven polypropylene plastic microfibres. Moreover, they merely trap pathogens instead of destroying them. "In a hospital setting,
these masks are placed in special bins and handled appropriately,"
says La'szlo' Forro', head of EPFL's Laboratory of Physics of Complex
Matter. "However, their use in the wider world -- where they are tossed
into open waste bins and even left on the street - - can turn them into
new sources of contamination."

========================================================================== Researchers in Forro''s lab are working on a promising solution to
this problem: a membrane made of titanium oxide nanowires, similar
in appearance to filter paper but with antibacterial and antiviral
properties.

Their material works by using the photocatalytic properties of titanium dioxide. When exposed to ultraviolet radiation, the fibers convert
resident moisture into oxidizing agents such as hydrogen peroxide, which
have the ability to destroy pathogens. "Since our filter is exceptionally
good at absorbing moisture, it can trap droplets that carry viruses and bacteria," says Forro'. "This creates a favorable environment for the
oxidation process, which is triggered by light." The researchers' work
appears today in Advanced Functional Materials, and includes experiments
that demonstrate the membrane's ability to destroy E.

coli, the reference bacterium in biomedical research, and DNA strands
in a matter of seconds. Based on these results, the researchers assert
-- although this remains to be demonstrated experimentally -- that
the process would be equally successful on a wide range of viruses,
including SARS-CoV-2.

Their article also states that manufacturing such membranes would be
feasible on a large scale: the laboratory's equipment alone is capable
of producing up to 200 m2 of filter paper per week, or enough for up to
80,000 masks per month.

Moreover, the masks could be sterilized and reused up a thousand
times. This would alleviate shortages and substantially reduce the amount
of waste created by disposable surgical masks. Finally, the manufacturing process, which involves calcining the titanite nanowires, makes them
stable and prevents the risk of nanoparticles being inhaled by the user.

A start-up named Swoxid is already preparing to move the technology out of
the lab. "The membranes could also be used in air treatment applications
such as ventilation and air conditioning systems as well as in personal protective equipment," says Endre Horva'th, the article's lead author
and co-founder of Swoxid.


========================================================================== Story Source: Materials provided by
Ecole_Polytechnique_Fe'de'rale_de_Lausanne. Original written by Emmanuel Barraud. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Endre Horva'th, Li'dia Rossi, Cyprien Mercier, Caroline Lehmann,
Andrzej
Sienkiewicz, La'szlo' Forro'. Photocatalytic Nanowires‐Based
Air Filter: Towards Reusable Protective Masks. Advanced Functional
Materials, 2020; 2004615 DOI: 10.1002/adfm.202004615 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200807093800.htm

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