Development of alumina supported ternary mixed matrix membranes for separation of H2/light-alkane mixtures

Ternary component mixed matrix membrane was prepared from PES, SAPO-34 and 2-hydroxy 5-methyl aniline on a macroporous alumina disk by the solvent evaporation method in order to investigate the effect of existence of an inorganic support. The membrane and its pure PES/Alumina counterpart were characterized by single gas permeability measurements of H2, CH4, C2H6 and C3H8. The corresponding H2/CH4 selectivities of membranes were 71.3 and 41. The membranes were also used to separate equimolar mixtures of H2 with CH4, C2H6 and C3H8 over a temperature range of 35–90 °C. The separation selectivities of ternary component membrane were 73.4 for H2/CH4, 242.9 for H2/C2H6 and >1000 for H2/C3H8 at 35 °C, which are comparable to the separation selectivities of pure PES on alumina. The permeances of all gases through PES/SAPO-34/HMA/Alumina membrane were, however, higher than those through PES/Alumina membrane at 90 °C. Despite its very complex morphology, the PES/SAPO-34/HMA/Alumina membrane preserved its structure and quality during the separation of different gas mixtures over temperature cycles between 35 and 90 °C. The CO2 and CH4 adsorption isotherms of PES-SAPO-34-HMA system were also obtained at 25 °C. The adsorption capacity of ternary component system was 1.55 mmol CO2/g and 0.45 mmol CH4/g, which is appreciably higher than the adsorption capacity of pure PES.