Nanostructured Membranes

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Membrane based separation processes typically require less energy than competing technologies but are often limited by low flow rates and low selectivities. Advanced nanomaterials open new possibilities for membrane designs that could revolutionize membrane technology through enhanced permeance and selectivity. The orders of magnitude higher performance predicted for nanostructured membranes would improve the efficiency of separation systems for clean water and energy in Canada and abroad, including those for natural gas purification, petrochemical separations, carbon capture, and desalination. Nanostructured membrane designs include those made from carbon nanotubes or atomically thin materials, such as graphene. Their structures contain atomic-scale flow passages that can reject molecules based on size or affinity while providing fast flow of the selected species. However, significant challenges remain to realize high performance nanostructured membranes on a practical scale. This research program will focus on developing nanostructured membrane technology and understanding fluid flow through their sub-nanometer structures. We will develop atomically-thin membranes by targeting the two major obstacles to their scalability: leakage through material defects and pore size non-uniformity. Two-dimensional materials beyond graphene, including those with inherent nanoporosity, will be explored for advantages in membrane systems. We will pioneer new carbon nanotube membrane designs, such as composite graphene-carbon nanotube membranes and membranes from carbon nanotubes with highly porous walls. We will experimentally study gas, liquid, and ion flow through single sub-nanometer pores in nanostructured membranes to better understand mass transport at the smallest length scale. This research program will lead to discoveries in fundamental nanofluidics and improvements in the performance and scalability of nanostructured membrane technology. The significant performance gains promised by this technology would reduce the energy costs of a number of industrial separation processes relevant to Canada. It would expand the use of membranes in natural gas purification and petrochemical separation in the oil and gas industry. The extremely high permeance possible would enable economical carbon capture by near atmospheric pressure separation or oxygen enrichment for reduced emission power generation. The cost of water treatment and desalination processes will also be reduced. On the fundamental side, we will develop new tools to measure fluid flows on scales smaller than the detection limits of current instruments and may discover new fluid flow phenomena as the atomic-scale details of boundaries become important. This research program will advance the field of nanostructured membrane technology, impacting a variety of chemical and mechanical engineering separation processes.