Manufacturing Nanoporous Materials for Energy-Efficient Separations

Abstract Chemical separations account for approximately 45%–55% of the US industrial energy use. The energy and associated carbon costs for fluid separation processes can be substantially reduced by avoiding thermally driven technologies. Advanced separation techniques such as membranes and pressure swing adsorption can debottleneck or even replace conventional thermally driven separation processes such as distillation, evaporation, or crystallization. Nanoporous membranes and adsorbents are particularly well-positioned to achieve this lofty goal due to their ability to provide exquisite size-, shape-, and affinity-based separations. Membrane materials separate mixtures utilizing the difference in molecular diffusivities within confined nanopores and the difference in molecular interactions with the membrane materials, while adsorption materials complete this task via selective adsorption of a certain species instead of others. Emerging and existing nanoporous materials utilized in membrane and adsorption applications will be presented, including zeolites, metal-organic frameworks, porous polymers, and carbon molecular sieves. A majority of this chapter is devoted to the manufacturing processes for nanoporous membrane and adsorbent materials. Spinning of hollow fiber membranes and sorbent fibers, fabrication of thin film composites, and polymeric membrane pyrolysis will be discussed in detail. This chapter also provides an introduction to sustainability-focused industrial applications of nanoporous materials for a variety of chemical separations, including carbon capture, gas separations, and organic solvent separations.