Microwave Catalytic Desulfurization and Denitrification Simultaneously on Fe/Ca-5A Zeolite Catalyst

Abstract

Simultaneous desulfurization and denitrification has been investigated using a microwave reactor packed with ammonium bicarbonate (NH4HCO3) and Fe/Ca-5A zeolite or Fe/Ca-5A zeolite only. The experimental results showed that 95.6% of sulfur dioxide (SO2) and 97.3% of nitrogen oxides (NOx) could be removed in the microwave reactor filled with NH4HCO3 and Fe/Ca-5A zeolite; a microwave reactor with Fe/Ca-5A zeolite only could also be used to microwave catalytic oxidative 69.5% SO2 to sulfate and 79.3% NOx to nitrates. The desulfurization and denitrification effect of the experiment using a microwave reactor with Fe/Ca-5A zeolite only is close to that of catalytic reduction of SO2 and NOx using ammonium bicarbonate and Fe/Ca-5A zeolite together. The optimal microwave power and empty bed residence time (EBRT) on microwave catalytic reduction desulfurization and denitrification simultaneously are 280 W and 0.358 s, respectively. The mechanism for microwave catalytic reduction of SO2 and NOx simultaneously can be described as the microwave-induced reduction catalyst reaction between SO2, NOx, and ammonium bicarbonate, with Fe/Ca-5A zeolite being the catalyst and microwave absorbent. Microwave catalytic reduction reaction of SO2 and NOx with the Fe/Ca-5A zeolite catalyst follows Langmuir−Hinshelwood kinetics.