Thermal Adsorption and Desorption Spectroscopic Study in RHO-Type Zeolite for Hydrogen Isotope (D ₂ /H ₂ ) Separation

Hydrogen isotope (H2, D2) separations in RHO-type zeolites having 0.36 × 0.36-nm pores were evaluated via temperature-programmed desorption and temperature-programmed adsorption. The synthesized Na,Cs-RHO zeolite was exposed to a mixed gas (H2/D2 = 50.7/49.3) at 196, 250, and 273 K, followed by desorption measurements starting at 77 K. A desorption peak was observed at approximately 190 K, and the D2/H2 selectivity was estimated to be approximately 1.4, which was independent of the exposure temperature. Furthermore, measurements confirmed adsorption of both H2 and D2 near 190 K. The adsorption of H2 and D2 at these high temperatures was also supported by sorption isotherm results.