Synthesis of a mordenite membrane on a stainless-steel filter and polytetrafluoroethylene plate substrates

A mordenite membrane could be synthesized on a stainless-steel filter and polytetrafluoroethylene (PTFE) plate. The membrane on the former was found to be crystallized in the void space of the filter. On PTFE the rectangular crystallites consisting of (001) and (110) faces were formed first, and then prismatic mordenite crystals were stacked on them. The formation mechanism was discussed on the basis of X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) observation. At the initial stage of membrane formation a silicon-rich component was susceptible to be incorporated in the crystal.