CO2 Selectivity of a new PDMS/PSf Membrane Prepared at Different Conditions

Abstract

Effect of water/solvent mixtures as coagulation medium with differing solvent content, coagulation bath temperature (CBT) and different coagulants on the gas permeation performance of polysulfone (PSf) membrane were investigated. The CO2/CH4 , H2/CO2 and CO2/N2 separation performance of membranes were studied by a constant pressure gas permeation experimental set up. The PSf membrane prepared at the CBT of 25°C (10-45°C range) showed the best gas separation performance with ideal selectivities of 43.9 and 39.8 for CO2/N2 and CO2/CH4 , respectively, and permeance of 21.5 GPU for CO2 at P=10bar. By increasing of the DMAc solvent into the gelation bath, ideal selectivities of CO2/CH4 and CO2/N2 have been reduced dramatically from 39.8 to 12.6 and 43.9 to 14.5, respectively at T=25°C and P=10bar. Using methanol as a coagulant resulted in less selective membrane compared with ethanol and water. But, the H2 and CO2 permeances were about 3 and 9 times more than those of ethanol and water coagulants, respectively. The coated membranes were given different heating temperature to investigate the suppression of undesirable CO2 plasticization. The membranes were stabilized against CO2 plasticization after heattreatment process.