EFRI DCheM: Re-Engineering the Nitrogen Cycle: Distributed Electrochemical Nitrogen Refineries for Ammonia Synthesis and Water Purification

Nitrogen pollution is a Grand Challenge identified by the National Academies. Fertilizer production has outpaced removal of nitrogen from wastewater, leading to continuous losses that threaten aquatic ecosystems and human health. This project aims to meet this challenge by recycling waterborne nitrogen pollutants into high-purity ammonia.

The PIs’ approach is unique in its ability to reduce nitrogen emissions and their negative cascade effects; reduce the energy and costs of conventional fertilizer production and wastewater treatment; and address legacy pollution that can persist for decades in coastal ecosystems like the Gulf of Mexico. The overall goal of this EFRI Distributed Chemical Manufacturing research project is to understand, design, and control multifunctional electrochemical processes that enable on-site fertilizer manufacturing and water purification with minimal environmental impacts.

The project combines fundamental breakthroughs in novel materials and processes to convert wastewater pollutants into products. The project includes integration of the fundamental discoveries with cost optimization and performance in various wastewaters, as well as prioritizing adoption locations and value propositions for recovery facilities. Because re-engineering the nitrogen cycle is a demanding challenge, it requires the best approaches from the entire U.S. talent pool.

Thus, the project team plans to broaden participation by hosting an annual workshop and demonstration day at a Stanford pilot-scale water treatment plant and invite underrepresented K-12 students; local community members; undergraduate researchers; and the project’s industrial advisory board representing fertilizer production, agriculture, and water treatment. The team will also develop workshops for incoming underrepresented undergraduate students, hands-on lab activities in classes, nitrogen-focused modules with K-12 students, and mentored research experiences for high school and undergraduate EFRI Scholars.

Current engineering efforts to rebalance the nitrogen cycle have largely concentrated on the improvement of the Haber-Bosch process to produce ammonia or expansion of nitrogen removal from wastewater. This project puts forward a transformative vision: recycling reactive nitrogen (e.g., ammonia, nitrate) in distributed nitrogen refineries that convert fugitive emissions in waste waters into high-purity ammonia.

The overall goal of the research is to understand, design, and control multifunctional electrochemical unit processes that enable distributed ammonia manufacturing and water purification with minimal environmental impacts. The project will utilize electrodialysis and nitrate reduction as a platform to benchmark and characterize ammonia-selective catalysts, as well as a treatment process applicable to two ubiquitous wastewaters: municipal wastewater and fertilizer runoff.

The project’s objectives are to: (1) understand and control electrocatalytic microenvironments via selective electrochemical reactive separations; (2) establish quantitative material and process innovation targets for energy-efficient, cost-effective, and adaptive processes; and (3) leverage economic and environmental assessments to prioritize local contexts and products for wastewater-derived ammonia manufacturing.

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.