Collaborative Research: ECO-CBET: A Photocapacitive/Electrolytic Reactor for Carbon Neutral Production of Clean Water and Value-added Products from Nitrate Contaminated Waters

Many agricultural, farming, and industrial processes release excess nitrate into the environment, making it the most pervasive groundwater pollutant in the world. This poses a serious threat to human and ecosystem health. Capturing and converting low nitrate concentrations from groundwater and surface waters is exceptionally challenging.

To address this pressing need for nitrate management across food and water systems, this project will bring together experts from various complementary disciplines to develop an integrated nitrate capture and conversion device that is efficient, low-cost, and powered by renewable resources. The device will use light energy to concentrate nitrate from waste streams (photocapacitive concentration) and electrically-driven chemical reactions (electrocatalytic conversion) to produce nitrogen and valuable chemicals such as ammonia.

This approach will provide insights into the chemical, physical, and catalytic processes involved in nitrate concentration and conversion, as well as the socioeconomic factors that limit the adoption of nitrogen management technologies. The project outcomes will advance the design of sustainable resource recovery systems to manage the nitrogen cycle and may reduce the cost of nitrate treatment.

Further, this research will empower resource-limited communities and industrial point source treatment operators to better address their nitrate water treatment needs. Graduate and undergraduate students at the University of Michigan, the University of Iowa, and the University of Texas at Austin will receive interdisciplinary technical training. The planned outreach activities will also provide opportunities to broaden the participation of underserved groups in STEM.

This project aims to develop an integrated photocapacitive concentration and electrocatalytic conversion technology for nitrate treatment. The project includes four research thrusts focused on developing and understanding this nitrate treatment technology. The first thrust advances the discovery and design of selective photocapacitive systems to capture and concentrate nitrate.

In the second thrust, the team will develop and test electrocatalysts made from inexpensive and earth-abundant elements that are durable and thermodynamically and kinetically compatible for nitrate capture and conversion to ammonia or nitrogen. The third thrust involves physics-based modeling and testing of the transport processes needed to optimize the photocapacitive capture and electrocatalytic conversion system.

The fourth thrust assesses process sustainability using technoeconomic and life cycle analyses to promote technology adoption by impacted communities. By integrating photocapacitive and electrocatalytic tools, this project will create a technology platform that sustainably captures and transforms nitrate, a regulated human health risk, into useful products.

This convergent research advances knowledge by simultaneously considering nitrate concentration and conversion, unlike existing studies that separate these steps. The project’s outreach activities include (1) creating an exchange program for interdisciplinary summer undergraduate research experiences to prepare students from underrepresented groups for graduate research; (2) engaging water treatment professionals and communities in Iowa and Texas who are working to address nitrate pollution; and (3) integrating best practices from NSF Research Traineeship programs focused on innovations at the nexus of food-energy-water systems.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.