板谷ゼオライトおよびその改質物の物理化学的性質と気体の吸着分離特性

Abstract

Itaya natural zeolite and its cation-treated zeolite were characterized by X-ray diffraction, thermo-gravimetric analysis, adsorption and chemical analysis. No change of X-ray diffraction pattern was found for Itaya zeolites treated with 1mol·dm-3 hydrochloric acid but a slight change of SiO2/Al2O3 ratio was found.The surface of Itaya zeolite seem to contain both meso- or macropores, but its heterogeneous surface became homogeneous with hydrochloric acid treatment, being predominantly composed of micropores. The monolayer adsorption capacity of zeolite for nitrogen gas decreased as the amount of cations in the Itaya zeolite increased. The cation (Na+, K+, NH+4, Ca2+) exchanged Itaya zeolite samples had less nitrogen adsorbing power than the hydrochloric acid-treated zeolite.The gas separation behaviour of Itaya zeolite was compared with that of the cation-treated zeolite. Separation of hydrogen, oxygen, nitrogen, methane and carbon monoxide from the surface of zeolites was investigated at 30-100°C by using Itaya zeolite and its cation-treated zeolite as column packings. Hydrogen, oxygen, nitrogen, carbon monoxide and methane were found to be separatable completely from the mixture gases by using Itaya zeolite, hydrochloric acid treated zeolite and its K+ exchange zeolites. A methane-oxygen mixture could not be separated by Na+, NH+4 and Ca2+ exchanged Itaya zeolites.