WWU’s Tim Kowalczyk receives ACS-PRF grant to study a more efficient way to separate carbon dioxide from exhaust

WWU Professor of Chemistry and Energy Studies Tim Kowalczyk was awarded a three-year, $70,000 grant from the American Chemical Society Petroleum Research Fund to investigate a more efficient method of carbon dioxide adsorption in industrial processes.

Kowalczyk seeks to answer how certain organic materials become selectively “sticky” for carbon dioxide and other gases when negatively charged. 

The process of pushing electrons on or off material to drive adsorption of carbon dioxide is called “electroswing adsorption.” It requires much less energy than traditional processes that utilize high pressure or temperature to separate carbon dioxide from flue gas. 

Named after the chimney or “flue,” flue gas is a mixture of gases produced by burning fuel, often by industrial furnaces or power plant boilers, or from chemical and physical processes involved in natural-gas processing. In addition to carbon dioxide, flue gas often includes nitrogen, water vapor and pollutants. 

Processes that separate the carbon dioxide from flue gas give operators control over how emissions are released, sequestered, processed or resold to industrial customers, Kowalczyk said. 

“Every molecule of carbon dioxide that forms through combustion of fossil fuels and isn't sequestered contributes to the cumulative warming impact of carbon dioxide in the atmosphere,” he said. “At 430 parts per million today, and rising more than two parts per million every year, the atmospheric concentration of carbon dioxide is over 50% higher than it was before the industrial revolution.”

Kowalczyk will focus on the mechanisms applicable to industrial point-source capture, “the low-hanging fruit” of industrial sources, and to direct air capture, he said.

“Like separating a few needles from a haystack, it is much harder to separate meaningful amounts of carbon dioxide from ambient air than it is to separate most of the carbon dioxide from CO₂-enriched flue gases at the site of combustion,” he said.

Current technological approaches to separating carbon dioxide from flue gas require significant ramping of pressure and temperature, both of which require a significant amount of additional energy. This energy is often sourced from combustion of fossil fuels, which releases its own carbon dioxide emissions. Kowalczyk’s work will inform new technological approaches in an effort to mitigate the environmental impact of these traditional processes.

Kowalczyk's research builds upon an experimental proof-of-concept for electroswing adsorption in industrial processes created by a team of researchers at the Massachusetts Institute of Technology.  His focus will be on understanding the fundamental science of how adsorption is enhanced by excess charge and how molecular structures can be modified to tune the selectivity and reversibility of the process. 

The grant, “Simulating the Scope and Mechanism of Electroswing Adsorption for Gas Separations,” will support summer research assistantships for undergraduate and master's students in the Kowalczyk lab over the next three years.

Students will work on modeling different pathways by which carbon dioxide can “stick” to the absorbent material and study how the embedding of absorbent active sites into a covalent organic framework (COF) affects the adsorption mechanism and selectivity. 

“COFs are networks of organic molecules that end up creating a larger three-dimensional lattice structure,” said Charlie DeFreest, who worked in Kowalcyzk’s lab as an undergraduate at Western and is now pursuing a doctorate at the University of Washington. 

These COFs are porous and their structure allows gases to flow through and absorb into the material easier. They also allow for maximum surface area, which makes studying specific reactions easier, she said. 

Students simulate the COFs and their specific reactions with computational models, which will be used for applied lab work in the future.

Kowalczyk’s lab previously studied COFs and their applications for solar energy. 

“The porous nature and crystallinity of COFs make them interesting materials for solar energy applications and for gas separations,” Kowalczyk explained. “This project bridges us over into the gas separations application space for COFs.”

To learn more about the work being done in the Kowalczyk lab, visit https://chemistry.wwu.edu/kowalct2/research-group

Mikayla King (‘17) covers the College of Science and Engineering and Woodring College of Education for University Communications. Reach out to her with story ideas at kingm24@wwu.edu.