“Biological engineering is a huge resource for us”: Undergraduate scholar studies biochar’s effects in PFAS water filtration

Winston-Salem native Sierra Franco wants to save our renewable resources. Climate resilience, minimizing our carbon footprint, and finding solutions to make drinking water safer are her passions, as well as her academic and career goals.

“I’ve always been attracted to agriculture and its Earth and environmental aspect,” said Franco, a bioengineering senior in the Department of Natural Resources and Environmental Design. “Just everything related to the Earth, the environment and how humans interact with it.”

Franco decided to enroll in N.C. A&T and the College of Agriculture and Environmental Sciences after acquaintances made her familiar with the college and its programs.

“I knew a lot of alumni,” said Franco.  “I liked that N.C. A&T wasn’t too far from home nor too close, and I could see that all the students that had graduated from A&T were very successful in their own career and their own fields. I wanted to mimic their path.”

Enrolling at the end of her senior year in high school, Franco received the Lewis and Elizabeth Dowdy Scholarship from N.C. A&T in March 2020 and  officially became an Aggie that spring as a biological engineering major, a field she found fascinating.

“Biological engineering aligned with the problems that I wanted to solve,” said Franco. “In trying to manipulate and harness the biological processes that are occurring around us, these abstract concepts we learn in class and making them practical and applicable in real life, biological engineering is a huge resource that we haven’t tapped into as much as we could.”

Franco applied to be an Undergraduate Research Scholar in 2022 and began working with associate professor Niroj Aryal, Ph.D., the next year on a project that has the potential to affect millions: determining whether biochar (a charcoal-like substance made from biomass sources such as wood chips, manure, and other agricultural wastes)  is effective in filtering out PFAS from

PFAS, or “per- and polyfluoroalkyl substances,” are a diverse group of chemicals that are used in hundreds of products, from toilet paper and food packaging to cosmetics and clothing. Used widely in industry since the 1940s, the chemicals are effective – but so resistant to water, grease and heat that they have earned the nickname “Forever Chemicals,” because they do not easily break down in the environment. Thanks to that durability, PFAS can enter the food supply through plants and animals grown, raised, or processed in contaminated areas and pose a lasting health risk to humans and the environment.

Sierra Franco, an Undergraduate Research Scholar who hopes to pursue a career in renewable resources, works on her project in the lab.

“We have PFAS in pretty good applications, like in firefighter foams for example, or in hairspray for anti-humidity purposes,” Franco explained. “The problem is those tiny chemicals are getting into our waterways, our soil and our bodies. They’re very hard to degrade or sift out because of their chemical properties. They provide scientists with a lot of challenges as far as maintaining air, water, and soil quality.”

People have explored the use of biochar for water filtration purposes already, said Franco. “Some people are using it to see, ‘Can we filter PFAS out of the water even though the material we’re using the filter may contain PFAS?’ That’s another consideration.”

While more than 4,000 chemicals can be classified as PFAS, Franco is focusing on the compound GenX. For her experiment, Franco will set up 12 identical columns, divided into four groups of three, to collect leachate, or water that has percolated from a solid and leached out some of the ingredients. Each of the four column groups will be filled with soil collected from N.C. A&T’s University Farm and mixed with different concentrations of biochar.

“The main barrier right now to choosing a lab,” said Franco. “The chemical we’re looking at is very specific and novel. The GenX compound was basically manufactured to replace another popular PFAS was in use before; because that replacement happened within the last 10-15 years, there aren’t many labs with the facilities to test for that compound.”

“She’s a very good student,” said Aryal. “She’s self-motivated. She’s put her mind to it and wants to solve the PFAS problem, which is a current issue happening all over the nation and a lot of our cities don’t have the resources to handle it yet. I applaud Sierra for wanting to tackle it with her research.”

For Franco, who was a freshman during the height of COVID-19, the Undergraduate Research Scholar experience has helped compensate for any limitations brought on by the pandemic.

“Dr. Aryal has been amazing,” said Franco. “I really do feel like I have the freedom to explore in this program, and he’s helped me by giving me suggestions and other sources to look at. His guiding knowledge has really helped me to feel more comfortable in a lab-research environment.”

Once she graduates in Spring 2024, Franco will either continue her research in graduate school or enter the energy industry to help ensure that positive impacts are reached.

“As the climate changes, and our resources become less available, renewables are something we should work toward,” said Franco. “I can see myself making sure that we are exploring renewable options and fortifying our electric grid to make sure that we are making lasting changes.”