(428e) Polyamide Thin-Film Composite Membranes for Gas Separations

Concerned about the impact of greenhouse gas emissions and climate change, the U.S. government has set ambitious carbon reduction targets. One of the key strategies involves significant investments in hydrogen as a low-carbon fuel with the potential to decarbonize transportation, industry, and electricity generation. Hydrogen is considered a viable option due to its capabilities in energy storage and ease of transport, as well as its zero-emission output. It's noteworthy that more than 95% of the 10 million metric tons of hydrogen produced in the U.S. is classified as grey.

Membrane-based gas separation is being extensively investigated for its potential to reduce both operational (OPEX) and capital expenditures (CAPEX), along with a smaller footprint compared to conventional methods like cryogenic distillation. Inorganics like carbon molecular sieves and zeolites and glassy polymers like polyimides, polyamides, PIMs, and block copolymers are being studied. Polyamide-based membranes have been extensively used for reverse osmosis (RO) but have interestingly rarely been considered for gas separation membranes. A recent study with tighter polyamide membranes demonstrated its use for gas separation applications [1].

In this work, we utilize electrospray to form polyamide membranes for gas separations. This process generates nano-sized droplets using a high electric field, allowing precise layer thickness up to 10nm, to deposit an ultra-thin selective polyamide layer on commercial porous supports. Electrospray is a versatile method that allows for easy control of monomer chemistry and concentrations. The resulting membranes show improved selectivity over conventional RO polyamides and the potential to control permeance and selectivity through careful selection of monomers.

[1]. Z. Ali, et. al.,"Gas separation and water desalination performance of defect-free interfacially polymerized para-linked polyamide thin-film composite membranes, JMS, 2021(618), 118572.