聚二甲基硅氧烷膜蒸汽渗透分离乙醇/二氧化碳的研究  

Study on vapor permeation separation of ethanol/carbon dioxide by polydimethylsiloxane membrane

作　　者：石新宇 谢纹纹 毛恒 王涛 陈欣如 齐昊 胡晓雪 赵之平 SHI Xinyu;XIE Wenwen;MAO Heng;WANG Tao;CHEN Xinru;QI Hao;HU Xiaoxue;ZHAO Zhiping(School of chemistry and Chemical Engineering,Beijing Institute of Technology,Beijing 102488,China)

机构地区：[1]北京理工大学化学与化工学院,北京102488

出　　处：《膜科学与技术》2024年第2期29-36,共8页Membrane Science and Technology

基　　金：国家重点研发计划课题(2021YFC2101203);国家自然科学基金项目(21736001,22008008);北京理工大学青年教师学术启动计划资助。

摘　　要：生物质发酵制乙醇过程中,发酵尾气的产生与排放对生态环境有极大影响.本文以聚偏氟乙烯(PVDF)多孔膜为基底,聚二甲基硅氧烷(PDMS)为分离层基质,制备出适用于发酵尾气乙醇/CO_(2)分离的PDMS/PVDF复合膜.通过红外光谱、X射线衍射、扫描电子显微镜等手段对PDMS/PVDF复合膜进行了系统表征,探究了热交联时间、进料压力、进料乙醇浓度、进料温度、吹扫气流量对PDMS/PVDF复合膜渗透分离性能的影响.结果表明,在PVDF基底上成功制备出薄约10.5μm、致密且均质的PDMS分离层.热交联时间越长,膜的选择性越低而渗透性升高;随着进料压力增加,膜的渗透性和选择性均升高;随着进料乙醇浓度升高,膜的渗透性和选择性均呈先升后降的趋势;随着进料温度升高,膜的渗透性和选择性均下降;随吹扫气流量的增加,膜的渗透性和选择性先升高后下降.在进料温度35℃、进料压力0.15 MPa(表压)、乙醇蒸汽体积分数0.1%时,所制PDMS/PVDF复合膜的乙醇渗透性高达33052.2 Barrer,乙醇/CO_(2)选择性为17.1.此外,在连续测试60 h中,所制复合膜性能保持稳定,在生物乙醇发酵尾气处理方面具有应用前景.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 CO_(2)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 10.5μm 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 33052.2 Barrer and the selectivity of 17.1 in separating 0.1%ethanol/CO_(2)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.

关 键 词：蒸汽渗透 聚二甲基硅氧烷 复合膜 发酵尾气 乙醇回收 

分 类 号：TQ028[化学工程] O634.41[理学—高分子化学]