乙醇

ABSTRACT(#br)Pervaporation is an alternative to distillation for recovering ethanol produced by fermentation of grains and biomass. Ethanol-selective mixed matrix membranes of the hydrophobic zeolite ZSM-5 in polydimethylsiloxane (PDMS) have superior performance compared to pure PDMS membranes in pervaporation of clean ethanol/water solutions, but are susceptible to performance reduction when pervaporating fermentation broths. The effects of pervaporating a variety of solutions with 60\u003cce:hsp sp=\"0.25\"/\u003ewt% ZSM-5/PDMS membranes were studied.

Abstract(#br)We report a thin-film composite (TFC) membrane fabrication method based on transfer of a pre-formed, cured active layer onto a microporous support. The active layer is cast on a polyvinyl alcohol (PVA) water-soluble film and cured, then the active side of the bilayer is placed against the skin side of the microporous support and the water soluble layer is dissolved. This method can be used with supports of relatively high pore size and porosity, thus reducing mass transfer resistance from the support.

交联剂是制备聚合物膜的重要因素，它不仅对成膜过程有重要影响，而且对膜结构和分离性能也有重要影响。然而，紫外交联膜用于有机物渗透汽化的研究很少。本工作中交联剂3 -甲基丙烯酰氧基丙基甲基二甲氧基硅烷( KH571 )对( 1 )紫外交联动力学的影响采用实时红外光谱和光流变仪表征，( 2 )通过交联密度表征膜结构，( 3 )通过乙醇渗透汽化评价分离性能。而且，传统的聚二甲基硅氧烷( PDMS )被聚二甲基硅氧烷-聚[ ( 3，3，3 -三氟丙基)甲基硅氧烷] ( PDMS-PTFPMS )嵌段共聚物所取代，其中较强的C-F键有助于增强膜的疏水性。结果表明，所有涂层溶液体系均采用超快速成膜工艺( 30 ~ 50 s )，分离性能优异，其中乙醇分离因子11.3，总通量1149 g m-2 h-1，60℃下5 wt %乙醇/水溶液渗透汽化回收。