Creation of hydrogen peroxide in situ could provide clean, drinkable water to communities in the poorest nations around the world
From: Cardiff University
July 1, 2021 -- A water disinfectant
created on the spot using just hydrogen and the air around us is millions of
times more effective at killing viruses and bacteria than traditional
commercial methods, according to scientists from Cardiff University.
Reporting their findings today in the
journal Nature Catalysis, the team say the results could
revolutionize water disinfection technologies and present an unprecedented
opportunity to provide clean water to communities that need it most.
Their new method works by using a
catalyst made from gold and palladium that takes in hydrogen and oxygen to form
hydrogen peroxide -- a commonly used disinfectant that is currently produced on
an industrial scale.
Over four million tonnes of hydrogen
peroxide are made in factories each year, where it is then transported to the
places it is used and stored. This means that stabilizing chemicals are often
added to the solutions during the production process to stop it degrading but
these reduce its effectiveness as a disinfectant.
Another common approach to disinfecting
water is the addition of chlorine; however, it has been shown that chlorine can
react with naturally occurring compounds in water to form compounds which, in
high doses, can be toxic to humans.
The ability to be able to produce
hydrogen peroxide at the point of use would overcome both efficacy and safety
issues currently associated with commercial methods.
In their study, the team tested the
disinfection efficacy of commercially available hydrogen peroxide and chlorine
compared to their new catalytic method.
Each was tested for its ability to kill
Escherichia coli in identical conditions, followed by subsequent analysis to
determine the processes by which the bacteria were killed using each method.
The team showed that as the catalyst
brought the hydrogen and oxygen together to form hydrogen peroxide, it
simultaneously produced a number of highly reactive compounds, known as
reactive oxygen species (ROS), which the team demonstrated were responsible for
the antibacterial and antiviral effect, and not the hydrogen peroxide itself.
The catalyst-based method was shown to
be 10,000,000 times more potent at killing the bacteria than an equivalent
amount of the industrial hydrogen peroxide, and over 100,000,000 times more
effective than chlorination, under equivalent conditions.
In addition to this, the catalyst-based
method was shown to be more effective at killing the bacteria and viruses in a
shorter space of time compared to the other two compounds.
It is estimated that around 785 million people lack access to water
and 2.7 billion experience water scarcity at least one month a year.
In addition to this, inadequate sanitation -- a problem for around
2.4 billion people around the world -- can lead to deadly diarrheal diseases,
including cholera and typhoid fever, and other water-borne illnesses.
Co-author of the study Professor Graham
Hutchings, Regius Professor of Chemistry at the Cardiff Catalysis Institute,
said: "The significantly enhanced bactericidal and virucidal activities
achieved when reacting hydrogen and oxygen using our catalyst, rather than
using commercial hydrogen peroxide or chlorination shows the potential for
revolutionizing water disinfection technologies around the world.
"We now have proven one-step
process where, besides the catalyst, inputs of contaminated water and
electricity are the only requirements to attain disinfection.
"Crucially, this process presents
the opportunity to rapidly disinfect water over timescales in which
conventional methods are ineffective, whilst also preventing the formation of
hazardous compounds and biofilms, which can help bacteria and viruses to
thrive."
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