Increased runoff of nitrate to groundwater, rivers and coastal water has raised widespread concern, in the first place for the toxicity of nitrite formed during in vivo reduction of nitrate. Nitrate is accumulated in our water bodies through over-fertilization and oxidation of ammonia, acid deposition of airborne NOx, and the improper disposal of nitrate-laden wastewater (sewage, agricultural, industrial). Current regulations for drinking water limits the maximum allowed concentrations of nitrate and nitrite at 50 and 0.5 mg/L, respectively.
Electrocatalytic denitrification offers several important advantages over other technologies for nitrate removal (e.g., biological remediation, ion exchange, reverse osmosis): no use of chemicals, no formation of sludge or waste streams, avoidance of pathogens in the remediation of drinking water; and suitability for the remediation of industrial wastewater for which bacterial growth is unviable. Moreover, modular design and small footprint of electrochemical systems make them highly attractive for decentralized water treatment. They can also be solar-powered and use direct current produced by photovoltaic modules.
In this project, we are developing novel, porous three-dimensional cathode materials based on carbon and metal-based nanomaterials, for selective reduction of nitrate to nitrogen gas (N2). The main objective is to minimize the formation of reduction byproducts (i.e., NH3, N2O), and obtain high reaction rates for nitrate removal.