New membrane sets record for separating hydrogen from CO₂

[sue4e3]

https://phys.org/news/2025-11-membrane-hydrogen.html
not a world saver but interesting
When designing membranes that separate industrial gases, scientists often incorporate structures that attract the gas they want to obtain. This attraction can enhance the membrane's permeability, and help isolate the desired gas more efficiently.
A study today in Science Advances shows that sometimes the opposite can occur—the chemically enhanced membrane can bind too strongly to the intended gas, thus slowing the membrane's permeability and reducing the separation efficiency.

The study describes these phenomena with carbon dioxide (CO2) and a membrane made of crosslinked polyamines, which are a CO2-attracting polymer. Experiments and simulations show the crosslinked polyamines slowing CO2's passage through the membrane.
The discovery gave Lin and his collaborators an idea. Since the membrane so effectively stymied CO2's movement, might it excel at separating hydrogen from CO2? (The two gases are often part of industrial gas separation byproducts, and purified hydrogen is critical for clean energy fuel cells.)

The scientists completed an additional set of experiments and found that the membrane achieved a record-breaking selectivity of 1,800, meaning it allows hydrogen to pass through 1,800 times more easily than CO2. In addition to its selectivity, the crosslinked polyamines can be made into industrial thin-film composite membranes, demonstrating its potential for commercialization. It also self-heals, and remains stable under extreme conditions.