Removal of NO by a continuous microwave discharge at atmospheric pressure w
ith the addition of CH4 is reported. The conversion of NO to N-2 is approxi
mately 80%, and the energy efficiency is up to 0.55 g-NO/kWh. The effects o
f CH4 addition and three discharge modes on NO conversion and energy effici
ency are investigated. The dependence of NO conversion on experimental time
is also observed.