The role of non-thermal plasma technique in NO_x treatment: A review

Non-thermal plasma (NTP) has been introduced over the past several years as a promising method for nitrogen oxide (NO_x) removal. The intent, when using NTP, is to selectively transfer input electrical energy to the electrons, and to not expend this in heating the entire gas stream, which generates free radicals through collisions, and promotes the desired chemical changes in the exhaust gases. The generated active species react with the pollutant molecules and decompose them. This paper reviews and summarizes relevant literature regarding various aspects of the application of NTP technology on NO_x removal from exhaust gases. A comprehensive description of available scientific literature on NO_x removal using NTP technology is presented, including various types of NTP, e.g. dielectric barrier discharge, corona discharge and electron beam. Furthermore, the combination of NTP with catalyst and adsorbent for better NO_x removal efficiency is presented in detail. The removal of NO_x from both simulated gases and real diesel engines is also considered in this review paper. As NTP is a new technique and is not yet commercialized, there is a need for more studies to be performed in this field. © 2014 Elsevier Ltd.