Researchers at the North Carolina State University have shown that 3D printing can be used to make carbon dioxide filters. The researchers at the university printed a hydrogel that could hold carbonic anhydrase – an enzyme that speeds up a reaction to turn carbon dioxide and water in bicarbonate. These findings suggest that 3D printers could be used to make filter designs faster and more efficiently.
“This manufacturing process, using 3D printing, makes everything faster and more precise,” said Jialong Shen, the study’s lead author and assistant research professor of textile engineering, chemistry, and science at NC State. “If you have access to a printer, and the raw materials, you can make this functional material.”
In the study, researchers in the NC State Wilson College of Textiles mixed a solution containing two different organic compounds – or the printing ‘ink’ – and an enzyme called carbonic anhydrase. Researchers then printed filaments like threads of hydrogel in a grid-like pattern, solidifying the solution as they printed it with UV light.
“We formulated the hydrogel in a way that would be mechanically strong enough to be 3D printed, and also extruded into a continuous filament,” said Shen. “The inspiration behind our design was our own cells, which have enzymes packed into compartmentalized spaces, filled with a fluid. That kind of environment is good for helping enzymes do their job.”
The researchers tested the properties of the material to understand how well it would bend and twist, and investigated the filter’s carbon capture performance. In a small-scale test, the filter absorbed 24% carbon dioxide. While the capture rate is lower than what they’ve achieved in previous designs, the filter was less than an inch (approximately 2cm) in diameter, and it could be made larger and in different modular shapes in order to stack them in a tall column – which would reportedly increase the capture efficiency.
“In order to get a higher capture rate, we would need to make the filter larger in diameter, or stack more filters on top of each other,” said Shen. “We don’t think that’s an issue; this was an initial test at a small scale for ease of testing.”
Researchers also tested durability of the material and found that it retained 52% its initial carbon-capture performance after 1,000 hours.
“This work is still early stage, but our findings suggest there are new ways to make materials for carbon capture devices,” said Sonja Salmon, the study’s co-corresponding author, and associate professor of textile engineering, chemistry, and science at NC State. “We’re offering hope for carbon capture.”
The study, “Carbonic Anhydrase Enhanced UV-Crosslinked PEG-DA/PEO Extruded Hydrogel Flexible Filaments and Durable Grids for CO₂ Capture,” was published online in Gels. Sen Zhang, Xiaomeng fang and others were also co-authors. Funding was provided by North Carolina State University, the Novo Nordisk Foundation, and the Alliance for Sustainable Energy, LLC – Managing and Operating Contractor for the National Renewable Energy Laboratory for the US Department of Energy.