Study on vapor permeation separation of ethanol/carbon dioxide by polydimethylsiloxane membrane
During the production of bioethanol,the generation and emission of fermentation exhaust gas have a significant impact on ecological environment.In this study,the PDMS/PVDF composite membranes suitable for the vapor permeation(VP)separation of ethanol from CO2 were prepared by casting the polydimethylsiloxane(PDMS)separation layer upon the polyvinylidene fluoride(PVDF)porous substrate.The microstructures of PDMS/PVDF composite membranes were systematically characterized by FTIR,XRD,and SEM.The effects of thermal crosslinking time,feed pressure,ethanol concentration,feed temperature,and sweep gas flow rate on the separation performance of the PDMS/PVDF composite membranes were explored.The results showed that the dense and homogeneous PDMS separation layer about 10.5 μm was successfully prepared.Longer thermal crosslinking time led to lower selectivity and higher ethanol permeability.The higher feed pressure resulted in higher ethanol permeability and membrane selectivity.As the feed ethanol concentration increased,the ethanol permeability and selectivity first increased and then decreased.Higher feed temperature resulted in lower ethanol permeability and selectivity.Higher sweep gas flow rate led to a trend of first increased and then decreased of ethanol permeability and selectivity.The as-prepared PDMS/PVDF composite membrane achieved an ethanol permeability of 33 052.2 Barrer and the selectivity of 17.1 in separating 0.1％ethanol/CO2 system under 0.15 MPa(gauge pressure)at 35 ℃,and remained a stable separation performance after 60 hours of testing.Therefore,the PDMS/PVDF composite membrane exhibits great application potential in the treatment of exhaust gas from bioethanol fermentation.
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万方数据
维普
