Electrochemical Wastewater Refining: Catalysis and Separations for Distributed Ammonia Manufacturing


Wednesday, December 1, 2021 - 8:45am


ENGR II 1519


William Tarpeh - Stanford University


Historically, wastewater has been viewed as a source of pollutants that must be mitigated before discharge. Recent decades have advanced this removal paradigm toward recovery, which requires selective separations. The next frontier of wastewater treatment will include wastewater refining, which requires integrated catalysis and separation steps to capture reactants from complex feedstocks, convert them to products, and purify those products into commodity chemicals. Ammonia is an urgent and timely product to manufacture from wastewater, especially given the drastic effects that humans have wreaked on the global nitrogen cycle. Managing the nitrogen cycle is an Engineering Grand Challenge because Haber-Bosch fertilizer production outpaces wastewater nitrogen removal 100-fold, leading to a net discharge of reactive nitrogen (e.g., ammonia, nitrate) that threatens aquatic ecosystems and costs the U.S. over $200 billion annually. Refining nitrate and ammonia into valuable products through reactive separations can address both water pollution and chemical manufacturing. This seminar will focus on electrochemical nitrate reduction to ammonia via molecular and heterogeneous catalysts integrated into separation processes that leverage electrodialysis and dynamic bias. Investigations into active sites, kinetic benchmarking, and process performance will be leveraged toward the vision of electrochemical wastewater refining.


Dr. William Tarpeh is an assistant professor of chemical engineering at Stanford University. The Tarpeh Lab develops and evaluates reactive separations to refine wastewater pollutants into valuable products, emphasizing the multi-scale insights between molecular mechanisms, novel unit processes, and systems-level assessments. Will completed his B.S. in chemical engineering at Stanford, his M.S. and Ph.D. in environmental engineering at UC Berkeley, and postdoctoral training at the University of
Michigan in environmental engineering.