The new filter is capable of capturing particulates and toxic chemicals that current filters are unable to capture
Poor air quality is a factor in diseases such as asthma, heart disease and lung cancer. Commercial air purifiers remove tiny particles of soot, smoke or car exhaust, which could be inhaled directly into the lungs, but air pollution also often contains other dangerous gaseous molecules, such as carbon monoxide and other organic compounds. volatile. An air filter made with corn protein rather than petroleum products can simultaneously capture small particulates and toxic chemicals like formaldehyde, elements that current air filters cannot capture. The research could lead to better purifiers, particularly in regions of the world suffering from very poor air quality. Washington State University engineers have published the design and material testing for this bio-based filter in Separation and Purification Technology journal. “Particulate matter is not that challenging to filter out, but simultaneously capturing various types of gas chemical molecules is more meaningful,” said Katie Zhong, of Washington State University’s School of Mechanical and Materials Engineering. “These protein-based air filtration materials should hold great promise for capturing more species of air pollutants.”
Choice of corn protein
With micron-sized pores, typical high-efficiency particulate air filters, also known as HEPA filters, are capable of capturing small particles, but not gaseous molecules. Most of the time they are made of petroleum products and glass, which leads to secondary pollution when old filters are thrown away, Zhong said. WSU researchers developed a greener air filter made of corn protein fibers that was able to simultaneously capture the 99.5% of small particlessimilar to commercial HEPA filters, el87% of formaldehyde, a value higher than that of air filters specially designed for this type of toxic substances. The researchers chose to study corn because of its abundance as an agricultural commodity in the United States. Corn protein is also hydrophobic, meaning it repels water and could perform well in a moist environment. The amino acids in corn protein are known as functional groups. When exposed on the protein surface, these functional groups act like multiple ‘hands’, gripping toxic chemical molecules. The researchers demonstrated this by exposing a functional group on the surface of the protein, which actually grabbed the formaldehyde. They theorize that further protein rearrangement could develop a series of tentacle-like functional groups that could grab a variety of chemicals from the air. The developed three-dimensional structure is more promising in the perspective of a simple manufacturing method, compared to the protein thin films previously developed by the research team. They used a small amount of a chemical, polyvinyl alcohol, to glue the nanofibers together into a lightweight material foam-like.
“This work provides a new way to manufacture multifunctional, environmentally friendly air filters made from abundant natural biomass,” said Zhong. “I think it’s very important for people’s health and the environment, and it should be commercialised.”
