Nanocomposite membranes functionalized with facilitated transport and molecular sieving for challenging gas separations

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The proposed research will pursue a transformative approach to developing nanocomposite membranes functionalized with facilitated transport and molecular sieving to effect gas separations that are important to Canadian industries, but challenging to carry out with current technologies. Specifically, this research aims at developing cutting-edge mixed-matrix nanocomposite membranes with both facilitated transport and molecular sieving functionalities tailored for (1) olefin/paraffin separation (to replace or complement with traditional energy-intensive cryogenic distillation), (2) CO2 capture from flue gas (for greenhouse gas emission control), and (3) removal of N2 from CH4 for upgrading sub-quality natural gas. Olefin separation and natural gas denitrogenation are two most challenging operations in the gas industry, and flue gas separation is critical for carbon capture to mitigate greenhouse gas emission. Built on our accomplishments in innovative membranes via nanostructuring and functionalization, this work will lead to breakthroughs in advancing up-scalable membranes for these challenging gas separations, which are all directly related to Canada's petrochemical, resource and energy sectors. The fundamental aspects of the facilitating agents, the molecular sieving materials, and the synergy of both functions in the membrane for enhanced separation will be investigated. For facilitated transport of olefin and CO2, the facilitating agents will function as a "carrier" to transport the target gas molecules across the membrane. Silver ions and amine molecules (both monomeric and polymeric amines) will be chosen as the facilitating agents for olefin and CO2, respectively, to exploit the specific olefin-silver and CO2-amine interactions. For N2/CH4 separation, suitable facilitating agents are lacking, and instead block copolymers with micro-biphase separated nanostructures will be used as the base membrane to achieve N2/CH4 separation based on discretive diffusion. In all cases, the membranes will be incorporated with appropriate MOF/ZIF sieves to further augment the separation via molecular sieving . The resulting mixed matrix nanocomposite membranes are expected to exhibit superior performance due to combined facilitated transport and molecular sieving (for olefin and CO2 applications) and the double discretive diffusivities of the base polymer and MOF/ZIF sieves towards N2/CH4 gas pair. A composition-nanostructure-permselectivity relationship will be established to guide development of these novel membranes for practical applications. This research is highly original and innovative; this is the first time that facilitated transport is integrated with molecular sieving within a membrane. Not only does this work directly address Canada's industrial needs for advanced membranes, it will also contribute significantly to advancing knowledge and training of highly qualified personnel.