Scientists from the University of Houston, in collaboration with others, have engineered an air filter that can trap SARS-CoV-2 and kill it instantly. The filter is made from commercially available nickel foam heated to 200 degrees Centigrade (392 degrees Fahrenheit).
Virus tests at the Galveston National Laboratory found that 99.8% of the SARS-CoV-2 virus was killed in a single pass and that 99.9% of the anthrax spores were also killed.
“This filter could be useful in airports and in airplanes, in office buildings, schools, and cruise ships to stop the spread of COVID-19,” said Ren, MD Anderson Chair Professor of Physics at the University of Houston and the co-corresponding author for the paper.
“Its ability to help control the spread of the virus could be very useful for society.”
The researchers said that since the virus can remain in the air for about three hours, creating a filter that could remove it from the air was crucial. The researchers also knew the virus could not survive temperatures above 70 degrees Centigrade (158 degrees Fahrenheit).
As such, they decided to create a heated filter and make the filter temperature far hotter in order to kill the virus almost instantly. They used nickel foam for the air filter because it is porous, electrically conductive, and flexible.
The researchers encountered one problem: nickel foam has low resistivity. To resolve that issue, they folded the foam, connecting multiple compartments with electrical wires to increase the resistance high enough to raise the temperature as high as 250 degrees Centigrade (482 degrees Fahrenheit).
"By making the filter electrically heated, rather than heating it from an external source, the researchers said they minimized the amount of heat that escaped from the filter, allowing air conditioning to function with minimal strain," said a press release from the University of Houston.