Electrochemical removal of NO and NO2 by using Ag(I)/Ag(II) redox mediator system in nitric acid medium by two-stage scrubbing process was investigated. Experiments were carried out for the complete removal of NO and NO2 from the stimulated flue gas at room temperature and atmospheric pressure. The process parameters like current density, Ag(I) concentration, HNO3 concentration, initial concentration of NO, Ag(I) concentration and temperature were studied and optimized. A removal efficiency of >99% was achieved using this sustainable redox process. Ag(II)/Ag(I) can be regenerated and reused for the scrubbing of waste gases continuously and there is no other gases emission during scrubbing. (c) 2009 Elsevier Ltd. All rights reserved.