Leanne Gilbertson: Shaping Sustainable Product Lifecycles

The ways in which we produce, use and dispose of consumer goods are fueling some of society’s biggest environmental problems, from declining water quality to climate change. While extricating ourselves from consumerism altogether isn’t realistic, creating more sustainable product lifecycles is—and new civil and environmental faculty member Leanne Gilbertson plans to do exactly that.

She joins Duke’s faculty on July 1, 2023 from the University of Pittsburgh, with support from the Duke Science and Technology initiative.

Gilbertson’s interest in sustainability research and development began early. A chemistry major and education minor at Hamilton College, Gilbertson started teaching high school chemistry right out of the gate. But she herself wasn’t done learning and returned to school to pursue a master’s degree and then a PhD in environmental engineering at Yale University. There, she discovered the “12 Principles of Green Engineering” through her advisor, Julie Zimmerman, and collaborations with the Center for Green Chemistry and Green Engineering.

Those principles, said Gilbertson, “remain a cornerstone of my research, in understanding how to fundamentally guide research and development in a way that is intended to protect the environment and human health. No matter what the project, those principles always serve as my compass.”

One of her current projects is funded by a five-year NSF CAREER award and is an exploration of more sustainable photocatalysts for water disinfection. “Carbon nitride is a photocatalyst that’s activated by visible light rather than higher-energy ultraviolet light, so there are energy savings in using that material,” explained Gilbertson. “By changing its chemistry and replacing carbon or nitrogen with other atoms like oxygen or boron, we can modify the optical bandgap, and that dictates the wavelength of light that can be absorbed to activate it.” Reactive oxygen species are not only capable of targeting and destroying bacteria in drinking water systems, but can also be used to degrade chemical contaminants, Gilbertson noted.

Generating energy savings during use is just a piece of the sustainability puzzle, though. Extracting and refining metals, which are introduced to change the electrical or optical properties of photocatalysts, involves intensive processing leading to immense embodied resource footprints. Avoiding metals typically reduces a material’s environmental impacts. Considering how materials are made, incorporated into products and recovered for reuse—rather than being thrown away and extracting new raw materials— closes the loop, facilitating what’s called the “circular economy.”

“During my postdoc, I started using the tool of lifecycle assessment, which allowed me to evaluate a material and product system quantitatively, to be able to ask, ‘what are the tradeoffs? Where are the big red flags and how can we proactively avoid them by conducting an assessment early in the product’s development?’” said Gilbertson.

Gilbertson’s other current area of focus is a new addition to Duke Engineering’s research portfolio: sustainable food production.

“Today’s predominant agriculture practices have depleted soils of nutrients, which then must be added back to the soils in order to grow crops. Essential nutrients are generally overapplied, with the excess having substantial impacts on the environment.”

LEANNE GILBERTSON, Associate professor of civil and environmental engineering 

“When I started as an assistant professor, I was really interested in the nitrogen emissions from crop production,” said Gilbertson. “Today’s predominant agriculture practices have depleted soils of nutrients, which then must be added back to the soils in order to grow crops. Essential nutrients are generally overapplied, with the excess having substantial impacts on the environment. It’s an inefficient process and we must do better.”

All the nitrogen-enriched runoff causes plant life to explode downstream, depleting oxygen in lakes, rivers and coastal regions. Without oxygen, aquatic life cannot survive. Gilbertson has been experimenting with delivering nitrogen on demand to corn plants, using pH levels as an environmental trigger. “The pH is different right next to the root than it is in the bulk soil,” explained Gilbertson. This pH change can signal to the carrier to break down and release the nitrogen, conveniently located where it can be taken up by the roots. “We are currently investigating the ability to slow the movement of nitrogen through the soil system so that, as the roots develop, it’s there and available when the plant demand is highest,” Gilbertson said.

Designing experimental systems at the nanometer or micrometer scale—regardless of the specific application—is challenging, and Gilbertson plans to leverage the characterization lab in Duke’s Shared Materials Instrumentation Facility to access information on interactions happening at the tiniest level.

But the farming community in North Carolina’s Piedmont region will be just as important as scientific equipment to Gilbertson’s research on food crops. 

“I’m super excited to explore local farms and local food procurement. There’s a growing agricultural community that is aware of environmental challenges associated with food production and is dedicated to shifting practices,” said Gilbertson. “Up until this point I’ve felt like a big missing piece of my research was the connection to the people on the ground—the farmers doing the work. For a technology to have an impact, it has to be adopted; to be adopted, it has to make sense to the user. Developing relationships with farmers here will help me understand how to make that happen.”

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