Microwave radiation's influence on sorption and competitive sorption in zeolites

The influence of microwave radiation on adsorption selectivity was studied using the adsorption and desorption of cyclohexane and methanol on high‐silica zeolites. The amount of microwave energy absorbed depends on the specific system of adsorbent and adsorbate. The adsorbent, a high‐silica zeolite, is effectively “transparent” to microwave radiation, while the two adsorbates reflect high (methanol) and low (cyclohexane) absorption of microwave energy. The measured system temperatures required for desorption by microwave energy were lower than those required for conventional heating. Further, microwave radiation can change the sorption selectivity; the adsorbate with the greater microwave absorptivity is desorbed selectively. It is concluded that the surface and adsorbed species can be heated selectively since the rate of microwave energy absorption can be greater than the rate of heat transfer from the surface.