The growth of SAPO 34 membrane layer on support surface for gas permeation application

The formation stage of SAPO 34 zeolite membrane on a tubular mullite support has been investigated. XRD, FESEM, IR and EDAX analysis techniques were used to explain the changes in crystallization stages as well as formation of membrane on tubular clay–alumina support with time. From the studies, the evidence tends to support that crystallization of SAPO 34 started from initial gel, proceed through cluster formation and accumulation followed by segregation and crystallization process. The study also showed the gradual incorporation of Si into AlPO4 phase and form cubical CHA phase after 120 h of synthesis time. Single gas permeation of CO2 and H2 showed that upto 300 KPa of feed pressure permeability of CO2 is more than that of H2. But at higher pressure the results show the reverse trend, flux is more for H2. This may be due to more adsorption of CO2 on SAPO 34 surface and less desorption from the surface than hydrogen with increasing pressure. The selectivity of H2/CO2 increases from 0.85 to 2.67.