Iron Catalysts to Repurpose Wastewater as Fertilizer: Making Ammonia from Nitrate and Nitrite
Rachel Chiang (SJSU), Nick A. Snyder (Stanford University), Dean M. Miller (Stanford University), Dr. William A. Tarpeh (Stanford University)
Advisor: Dr. Madalyn Radlauer (Department of Chemistry, SJSU)
Excessive nitrate and nitrite in our water systems, due to waste streams and fertilizer runoff, have severe consequences for both the environment and human health. An emerging method for their removal is electrochemical nitrate reduction using a transition metal catalyst, which can convert these harmful nitrate and nitrite pollutants into ammonia, a key feedstock. Our research focuses on iron-based electrocatalysts for nitrate reduction, as iron is a sustainable, inexpensive, and abundant transition metal. We are synthesizing several iron complexes that may be integrated into existing, well-developed electrochemical nitrate reduction systems. Our work includes the synthesis of our iron catalysts, characterizing them with Fourier transform infrared spectroscopy (FTIR), and testing their catalytic activity using cyclic voltammetry (CV) in a simple three-electrode chemical cell. We will also utilize more robust characterization techniques, such as ultraviolet-visible (UV-vis) spectroscopy and X-ray diffraction (XRD), as well as performing controlled potential electrolysis (CPE) to quantify the extent of nitrate reduction. Future goals involve integrating these iron catalysts into polymers to form cationic, water-soluble polymer-supported iron catalysts. We hypothesize these water-soluble polymeric support structures can enhance catalyst reactivity, advancing electrochemical nitrate reduction in wastewater treatment processes.
