New molecular sieve sorbent. Pillared clay vs. molecular sieve carbon

Gas separation in most of the commercial adsorption processes is accomplished by differences in adsorption equilibria, and may be referred to as equilibrium separation. MSC is the only molecular sieve available in which the pores are not uniform in size; rather, there is a distribution of pore sizes, in contrast to zeolite. This distribution of pore sizes gives rise to wide differences in diffusivities for different gases. It has been recognized that the limiting pore size is not the interlayer spacing, but is the interpillar spacing, which has been found to be distributed in the range of several angstrom (3). This distribution of micropore sizes, combined with its high surface area, makes PILC a promising competitor to MSC for kinetic separation. It is shown that the PILC compares favorably against MSC in the O₂ capacity for PSA.