渗透蒸发工艺

Abstract(#br)Bio-ethanol recovery via pervaporation process has drawn growing attention in the past few decades, however, its large-scale industry application remains limited due to the relatively low separation efficiency, especially in flux. In view of this, surface patterned nonporous PDMS (Polydimethylsiloxane) composite membranes with enhanced ethanol recovery efficiency were fabricated in this work. Line and space pattern was first printed on two-layer PVDF (Polyvinylidene fluoride) substrate using phase separation micromolding followed by modified immersion precipitation.

Abstract(#br)Bio-ethanol, clean and renewable, has proved to be a promising alternative energy resource to replace conventional fossil fuels. In its continuous production via the fermentation–pervaporation process, hydrophobic polymer membranes such as polydimethylsiloxane (PDMS) have been developed to enrich ethanol from dilute fermentation broth. However, the efficiency of current ethanol recovery via pervaporation is not high enough for large-scale bioethanol production.

表面的疏水性-亲水性能对膜的最终分离性能起着决定性的作用，特别是混合基质膜( MMMs )对各种有机体系从水溶液中渗透汽化回收的疏水性。本文以超疏水沸石咪唑酸骨架90 ( S-ZIF-90 )为填料，将其与聚二甲基硅氧烷( PDMS )共混，制备了超疏水S-ZIF-90 / PDMS微乳液，用于乙醇的选择性渗透蒸发。通过多种表征手段，对S - ZIF - 90和S - ZIF - 90 / PDMS微球表面的化学结构和超疏水性能进行了表征。结果表明，成功制备了S - ZIF - 90粒子和S - ZIF - 90 / PDMS复合膜，与ZIF - 90 / PDMS和纯PDMS相比，S-ZIF-90 / PDMS MMMs具有更高的疏水性。因此，S-ZIF-90 / PDMS MMMs比ZIF-90 / PDMS MMMs或纯PDMS表现出更优异的分离性能。特别是15  wt % S-ZIF-90负载的S-ZIF-90 / PDMS MMMs，在40  ℃，5  wt %稀乙醇溶液中，总通量为1064   g / ( m2 h )，最大分离因子为14.9  。通过吸附试验还计算了乙醇和水的扩散系数、渗透系数、吸附热(△H S )和吸附熵(△S )，为进一步确定MMMs在渗透蒸发过程中的传质机理提供了方法。