Sorption behaviour of silanated H-mordenite

Abstract

The changes in the sorption behaviour of H-mordenite resulting from the primary chemisorption of SiH₄, secondary reactions and oxidation of chemisorbed SiH_x with H₂O have been investigated, using O₂, N₂ and CO as sorbates at 0 and –196°C and at different stages in the treatment of the sorbent. The modified mordenite was much less open and while sorption equilibrium could be established at 0°C this equilibrium was not approached at –196°C. The wide-pore parent H-mordenite was converted to a narrow-pore molecular sieve within which migration, even of small sorbate molecules, involved activated diffusion. Sorption of N₂ at –196°C in H-mordenites at various stages of silanation showed that the primary chemisorption caused a big restriction in the channels, and that the oxidation stage with H₂O followed by outgassing at 360°C made the restrictions even more complete. Non-oxidative secondary reactions were less important.