CO2 and CH4 Permeation through SAPO-34 Zeolite Membranes Effect of Synthesis Temperature and Support Properties

In this research continuous SAPO-34 membranes were synthesized by secondary growth method onto both -alumina and mullite supports at three levels of synthesis temperature;185,195 and 220 for 24 h. The zeolite membranes synthesized were characterized by XRD, SEM and single gas permeation. It was found out that the support structural properties and synthesis temperature both have significant effects on membrane formation. By increasing synthesis temperature SAPO -34 crystals size which grown on mullite supports become uniform and smaller while crystals formed on a- Al2 O3 substrate become larger. The effect of synthesis temperature on single gas permeation properties of the synthesized SAPO- 34 membranes was also studied The permeance of CH4 and CO2 decreased as the synthesis temperature increased. But the CO2/CH4 ideal selectivity versus synthesis temperature follows two different trends for SAPO-34 membranes synthesized on mullite and a-Al2 O3supports. By increasing synthesis temperature, CO2/CH4 ideal selectivity decreased for - alumina supported membranes while for mullite supported ones increased Under optimum synthesis conditions at room temperature and 1 bar feed pressure the CO2 permeance through - alumina and mullite supported SAPO-34 membranes were 2.01 x 10 -6 and 7.86 x10 -8, , respectively and CO2/CH4 ideal selectivities were 13.91 and17.39 respectively.

Keywords:

SAPO-34 membranes , Mullite support , a -Al 2O3 support , Synthesis temperature , Ideal selectivity