Electron paramagnetic resonance and infrared study of type 5A zeolite reacted with SO2 and CO2

Abstract

In this work an electron paramagnetic resonance (EPR) and infrared (IR) study was made on molecular sieve type 5A zeolite reacted with SO2 and CO2 gases. The observed EPR signal from the SO2 reacted sample was attributed to the SO2- radical and its temperature dependence has been presented. However, CO2 reacted samples do not exhibit any EPR spectrum. The EPR spectra of SO2 reacted samples indicate that vibration modes shift somewhat as compared with its free state. For the CO2 reacted samples one of the modes shifts and the other doubles as compared with its free state. This indicates the adsorption of SO2 on surfaces, and absorption of CO2 in deep pores of this zeolite.