Abstract
In this research, continuous SAPO-34 membranes were synthesized via secondary growth method onto both α-Al
2
O
3
and mullite supports at three levels of synthesis temperature: 185, 195, and 220°C for 24 h. The synthesized membranes were characterized using XRD and SEM analysis and single gas permeation experiments. It was found out that support material and synthesis temperature both have significant effects on the membrane performance. At higher synthesis temperature, SAPO-34 crystals grown over the mullite support become more uniform and smaller in size but those grown on the α-Al
2
O
3
support become larger. Effect of synthesis temperature on single gas permeation properties of the synthesized SAPO-34 membranes was also studied. For the mullite supported membranes, the CH
4
and CO
2
permeances decrease as synthesis temperature increases; but in the case of the alumina supported membranes, by increasing synthesis temperature, CH
4
and CO
2
permeances first decrease up to 195°C and then increase up to 220°C. Even in equal membrane thicknesses, the mullite supported membrane shows lower gas permenaces. Increasing synthesis temperature decreases CO
2
/CH
4
ideal selectivity for the α-Al
2
O
3
supported membranes, while increases for the mullite supported membranes. Under optimum synthesis conditions, at room temperature and 2 bar feed pressure, the CO
2
permeance through the α-Al
2
O
3
and the mullite supported SAPO-34 membranes are 8.2 × 10
−7
and 8.5 × 10
−8
(mol/m
2
· s · Pa), respectively, and CO
2
/CH
4
ideal selectivities are 51 and 61, respectively.