The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were inves...The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were investigated.The CO_(2)/CH_(4),H_(2)/CH_(4) and H_(2)/N_(2) separation performance of the membranes were studied by gas permeation.Changing the N,N-dimethyl acetamide(DMAc)/water coagulation medium ratio from pure water to 90/10 vol%,resulted in a complete disappearance of the macrovoids throughout the polysulfone(PSf)polymeric matrix.The PSf membrane prepared in a CBT of 25℃ showed the best gas separation performance with ideal selectivities of 46.29,39.81 and 51.02 for H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) respectively,and permeances of 25 and 21.5 GPU for H_(2) and CO_(2) at 25℃ and 10 bar respectively.By increasing the amount of solvent in the gelation bath,the selectivities of H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) were dramatically reduced from 46.29,39.81 and 51.02 to 16.08,20.2 and 18.5 respectively at 25℃ and 10 bar.Reducing the CBT from 80℃ to 5℃ led to a complete elimination of macrovoids.Using methanol as a coagulant resulted in a less selective membrane compared with membranes from ethanol and water coagulants.The H_(2) and CO_(2) permeances were respectively about 3 and 9 times more than those for ethanol and water coagulants.Coated membranes were heated at different temperatures to investigate the suppression of undesirable CO_(2) plasticiza-tion.The membranes were stabilized against CO_(2) plasticization by a heat-treatment process.展开更多
基金grateful for the support provided by the Ferdowsi University of Mashhad(Grant No.35462)we are also indebted to the National Iranian Oil Refining and Distribution Company for its financial support.
文摘The effects of different solvent/water coagula-tion mediums,different coagulation bath temperatures(CBT)and different coagulants on the performance,morphology and thermal stability of polysulfone mem-branes were investigated.The CO_(2)/CH_(4),H_(2)/CH_(4) and H_(2)/N_(2) separation performance of the membranes were studied by gas permeation.Changing the N,N-dimethyl acetamide(DMAc)/water coagulation medium ratio from pure water to 90/10 vol%,resulted in a complete disappearance of the macrovoids throughout the polysulfone(PSf)polymeric matrix.The PSf membrane prepared in a CBT of 25℃ showed the best gas separation performance with ideal selectivities of 46.29,39.81 and 51.02 for H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) respectively,and permeances of 25 and 21.5 GPU for H_(2) and CO_(2) at 25℃ and 10 bar respectively.By increasing the amount of solvent in the gelation bath,the selectivities of H_(2)/CH_(4),CO_(2)/CH_(4) and H_(2)/N_(2) were dramatically reduced from 46.29,39.81 and 51.02 to 16.08,20.2 and 18.5 respectively at 25℃ and 10 bar.Reducing the CBT from 80℃ to 5℃ led to a complete elimination of macrovoids.Using methanol as a coagulant resulted in a less selective membrane compared with membranes from ethanol and water coagulants.The H_(2) and CO_(2) permeances were respectively about 3 and 9 times more than those for ethanol and water coagulants.Coated membranes were heated at different temperatures to investigate the suppression of undesirable CO_(2) plasticiza-tion.The membranes were stabilized against CO_(2) plasticization by a heat-treatment process.
