Simultaneous Removal of Ammonia and Nitrate from Wastewater Using a Pulse Electrolysis Technique

Abstract

The Environmental Protection Agency (EPA) considers ammonia and nitrate as large-scale threats to environmental quality and human health, causing impaired air quality, surface water eutrophication, and other serious health problems. This work examines the viability of using a pulse electrolysis technique to accomplish the simultaneous removal of ammonia and nitrate in an undivided flow cell using CuNi/PtIr supported on carbon electrocatalysts (CuNi/PtIr/C). Different series of PtIr/C and CuNi/C compositions were examined, and it was found that among all series of the synthesized catalysts, 60% Pt9Ir/C and 40% Cu9Ni/C had greater activity toward Ammonia Oxidation Reaction (AOR) and Nitrate Reduction Reaction (NRR), respectively. Throughout the pulsing potentials, the nitrogen contaminants were gradually removed with the overall reaction that generated harmless nitrogen and hydrogen gases. The average ammonia and nitrate removal rates were 5.17 ppm-ammonia and 0.074 ppm-nitrate/min, respectively. The selectivity of nitrate to ammonia was 82% with an average nitrate removal rate of 65%. The catalysts exhibited pronounced stability after 10 cycles of pulse electrolysis.