New membrane material offers longer life, less energy consumption (Farhatul Istiqomah)

Separation and purification processes consume an enormous amount of energy. These processes, including gas separation, water removal and hydrogenation reactions, are listed among the Department of Energy’s Energy Intensive Processes Portfolio. The energy issues stem from design limitations based on material limitations. A new material, however, may drastically improve efficiency for the long haul.

The work comes from a group of researchers studying the membranes used in separating out gases. The membranes are polymers with nanoscale holes in them. Those small holes limit the process efficiency, but when larger holes are tried, the membrane breaks down, or ages, rapidly.

      The idea with gas separation is to get one gas to pass through the membrane quickly while others don’t pass at all, or do so very slowly. Stopping the breakdown of the polymer used to accomplish this has been researched from many angles, but there hasn’t been a breakthrough to make higher efficiency and longer life a reality. Until now.

     In their recent article, Ending Aging in Super Glassy Polymer Membranes, the group used a nanocomposite of a super glassy polymer and a microporous microparticle - porous aromatic framework (PAF) to form a stabilized structure.

      The problem with the super glassy polymers is that they all age. The individual polymer molecules “relax” to a more favorable configuration thermodynamically, but this configuration is much less favorable for use as a membrane. The PAFs act to “lock” the structure in place so that aging is effectively halted and efficiency remains high.

      Enhancing membrane efficiency may help in many applications. The initial research was done on the separation of CO₂ and N₂, but the improved longevity and selectivity may have implications in many other separation processes as well.

      The improvement of separation processes is important for the efficiency of the process (energy in) and for the product (quality out). The reduction of energy consumption, coupled with the ability to selectively remove harmful effluents, offers a compact package for reducing the environmental impact of these important industrial processes.

http://www.engineering.com/DesignerEdge/DesignerEdgeArticles/ArticleID/7494/New-membrane-material-offers-longer-life-less-energy-consumption.aspx