Advanced carbons in membranes and filtration

Graphene oxide and reduced graphene oxide membranes are the most technically advanced in-scope carbons in filtration, offering angstrom-level pore control for ion separation, desalination and gas separation. Layered graphene oxide membranes with sub-nanometre interlayer spacing sieve ions by size and charge, with ion rejection above 95% demonstrated in the laboratory and commercial scaling under way. Carbon nanotube membranes move water extremely fast through their smooth, hydrophobic interiors, with reported water flux 3 to 5 times higher than polymer membranes of equivalent rejection.

In gas separation, graphene and carbon nanotube membranes sieve molecules through engineered pores and channels, with carbon dioxide to methane selectivity above 150 shown in a 2024 pilot, which supports membrane-based carbon capture. Biochar-derived carbons are used in water-treatment filtration as a distinct in-scope material, while activated carbon falls outside scope. MXenes are emerging as a membrane material valued for ion selectivity and fouling resistance.

The total membrane filtration market, spanning all membrane types, was valued at about $7.51 billion in 2024. Within it, the nanoporous membrane market, which contains the carbon nanotube and graphene subset, was worth about $890 million in 2024 and is growing at roughly 7.8% a year to 2030. The dedicated graphene membrane market was about $250 million in 2024 and is forecast to grow far faster, at around 18.5% annually to 2033, as graphene and nanotube membranes move from pilot to early commercial use.