Nazanin Charchi at the CLS


Researchers at the University of Saskatchewan are working on an air filter to destroy viruses like the one that causes COVID-19.

The idea is to capture airborne water droplets after someone coughs or sneezes, and to render viruses inside the droplets harmless by oxidizing them, says chemical and biological engineer, Jafar Soltan, MCIC.

The system is based on technology Soltan has been working on for the past 15 years. His filter was originally designed to clean indoor air of volatile organic compounds (VOCs) – air pollutants that off gas from furniture and other household items.

“When you buy a new car or a carpet, you can smell them. It’s a ‘new’ smell,” says Soltan. “That’s solvents off gassing from the polymers the car or carpet is made of, and they can cause health problems such as headaches.”

Jafar Soltan

Soltan’s filter can be installed in air conditioning systems and oxidizes VOCs using a manganese oxide-based catalyst in conjunction with a controlled amount of ozone. The combination breaks down VOCs into carbon dioxide and water.

When the pandemic began last year, Soltan teamed up with PhD candidate Nazanin Charchi to see if they could tweak the filter to handle viruses in airborne water droplets instead of VOC gases.

“As a chemical engineer, I don’t know too much about viruses. But they have building blocks of carbon and hydrogen that maybe our process can oxidize,” says Soltan. “So, we look at viruses as another hydrocarbon – a complex one, but who cares? If you can react its hydrogen and carbon with this method, basically you inactivate it.”

Soltan’s lab is not equipped to work with the COVID-19 virus, so he turned to colleagues from the department of medicine who are now helping him test the filter on a COVID-19 virus stand-in. It’s called a phage, a virus that parasitizes bacteria by infecting and reproducing inside them and which has the same basic structure as viruses that infect humans.

The team is using the Canadian Light Source (CLS) at the University of Saskatchewan to study the fresh and used catalysts to understand how to make them more active. If they can show the concept works, the researchers will then test it on the COVID-19 virus.

While the virus-busting filter will not likely be ready in time to deal with the current pandemic, Soltan and Charchi hope it will be used soon in schools, homes, and other indoor spaces.

“We are hoping our process will work for a wide variety of these pathogens in the air,” says Charchi.

Soltan likens his catalyst-based air filter to snakes used to take care of a mouse infestation in a warehouse: “You might not want to just release the snakes, but you can put the snakes in a cage. The catalyst and ozone are like snakes in a cage. You put them in box in air conditioning systems.”

Concordia University chemical and materials engineer Alex De Visscher, who is not involved in Soltan’s research, says the technique is promising.

“Ozone is a very corrosive molecule. Manganese oxide acts as a catalyst. It makes ozone even more aggressive. The combination of ozonation with a manganese oxide catalyst is capable of degrading organic air pollutants,” says De Visscher. “It makes sense that this combination would be able to deactivate viruses. That is, provided that the virus hits the surface of the manganese oxide.”