WSU researchers: Air filter made from corn could replace those made with petroleum products

PULLMAN, Wash. — It’s a wild possibility for managing air quality. Washington State University researchers say an air filter made from corn could replace ones that are made with petroleum products, and it may work better than a traditional air filter.

In a news release, WSU said the research could lead to better air purifiers, particularly in regions of the world that suffer from very poor air quality. Washington State University engineers report on the design and tests of materials for this bio-based filter in the journal Separation and Purification Technology.

WSU scientists believe the air filter made out of corn protein can capture small particles, but it may also catch toxic chemicals that current air filters can’t deal with, like formaldehyde.

“Particulate matter is not that challenging to filter, but to simultaneously capture various kinds of chemical gas molecules, that’s more significant,” said Professor Katie Zhong at WSU’s School of Mechanical and Materials Engineering. “These protein-based air filtering materials should be very promising to capture multiple species of air pollutants.”

HEPA air filters can capture small particles but not gas and they’re usually made of petrol products or glass; when they’re thrown away it hurts the environment. Corn would be biodegradable, and a filter that can catch chemicals could be used in emergencies.

Zhong is a corresponding author on the paper that is laying out the possibility of corn protein being used in air filters, and she says it could have many applications.

“If we can use corn, for example, corn protein to make the filters, like a facial mask, then we can not only help people’s health but also protect our environment,” said Zhong.

She says the use and disposal of facial medical masks during the pandemic has shown how much waste even small air filtering masks create. Zhong says the corn fiber for air filters could be applied to HEPA air filtration systems and may even be useful in an emergency.

Zhong said she has watched the news in recent weeks and saw the train derailment in Ohio, where toxic chemicals were burned and sent gas into the community of East Palestine. She admits that an air filter that could catch the chemicals and gases could be used to help protect people.

“Recently in Ohio — the toxic chemicals in the air — I really hope we can do something. As a scientist and a professor, I really hope I can do something for people’s health,” said Zhong.

Researchers at WSU will do more testing and hope to work with manufacturers to see if all of this could be applied.

WSU says poor air quality is a factor in diseases such as asthma, heart disease and lung cancer. Commercial air purifiers remove tiny particles in soot, smoke or car exhaust, which could be inhaled directly into the lungs, but air pollution also often contains other hazardous gaseous molecules, such as carbon monoxide, formaldehyde and other volatile organic compounds.

The WSU researchers developed a more environmentally friendly air filter made from corn protein fibers that were able to simultaneously capture 99.5% of small particulate matter, similar to commercial HEPA filters, and 87% of formaldehyde, which is higher than specially designed air filters for those types of toxins.

The researchers chose corn to study because of its abundance as an agricultural product in the U.S. The corn protein is also hydrophobic, which means that the protein repels water and could work well in a moist environment, such as in a mask.

The amino acids in the corn protein are known as functional groups. When exposed to the protein’s surface, these functional groups act like multiple hands, grabbing the toxic chemical molecules. The researchers demonstrated this by exposing a functional group at the protein surface, where it grabbed formaldehyde. They theorize that further rearrangement of the proteins could develop a tentacle-like set of functional groups that could grab a variety of chemicals from the air.

“From the mechanism, it’s very reasonable to expect that this protein-based air filter could capture more species of toxic chemical molecules,” said Zhong.

The three-dimensional structure that they developed also offers more promise for a simple manufacturing method than the thin films of proteins that the research team developed previously. They used a small amount of a chemical, polyvinyl alcohol, to glue the nanofibers together into a lightweight foam-like material.

“This work provides a new route to fabricating environmentally friendly and multi-functional air filters made from abundant natural biomass,” said Zhong. “I believe this technology is very important for people’s health and our environment, and it should be commercialized.”

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