Review of Discharge Plasma Treatment of NOX in Diesel Engine Exhaust: Progress in Stand-Alone and Cascaded Measures

This article is intended to provide a comprehensive review of the experimental studies conducted to understand the effect of several parameters involved in the discharge plasma-based nitrogen oxides (NO
_X
) removal from real diesel engine exhausts, be it stationary or automobile, in addition to simulated ones. In the last two decades, much progress has occurred in the electric discharge-based nonthermal plasma (NTP) treatment of exhaust gas with or without cascading any additional treatment technique, such as catalysts or adsorbents. Most of these studies were conducted with the aim of enhancing the removal of NO
_X
or studying the efficacy of a particular parameter on NO
_X
removal or both. It is now timely to collage the findings of these studies in a way to help the present researchers to understand the effect of various parameters/measures associated with stand-alone and cascaded NTP treatments for NO
_X
removal. It is also intended that the current review helps in moving closer to realizing the application of NTP in the cleansing of gaseous pollutants of diesel exhaust.