Molecular sieving offers industry a way to turn down the heat
A factory can spend considerable energy making a useful chemical, then spend still more separating it from the other substances travelling through its pipes. Even after that, some valuable material can leave in mixed gas streams because recovering it is difficult or expensive.
For Zurich-based UniSieve, those mixtures represent an opportunity. Its membranes sort molecules through openings far too small to see, offering an alternative to some of the heating and cooling used in industrial separation.
On 8 October 2026, the company announced a $9 million Series A to expand deployment. With its technology tested in industrial settings, UniSieve is working towards wider commercial use, where consistent manufacturing and sustained performance will determine how far it can grow.
How molecular-sieving membranes separate industrial gases
Take propylene, a raw material used to make polypropylene, the plastic found in food containers, household goods and car components. During polypropylene production, plants remove gas streams to prevent unwanted substances accumulating. These streams can contain reusable propylene alongside other hydrocarbons, including propane.
Because propylene and propane have similar boiling points, separating them through conventional distillation can demand substantial equipment and energy. Distillation repeatedly brings vapour and liquid into contact, progressively concentrating the components according to how readily they evaporate.
Recovering propylene from a suitable outgoing stream allows it to return to production. That can reduce the amount of fresh raw material a plant needs and keep useful molecules from being lost.
UniSieve approaches the separation through molecular size. Its membranes contain porous crystals whose openings can distinguish between molecules differing by fractions of an ångström. One ångström is one ten-billionth of a metre: a scale at which a tiny difference determines which molecule gets through.
Gas enters a cartridge, and a pressure difference drives selected molecules across the membrane. Others remain on the original side, creating two streams that can be routed towards recovery or further processing.
The separation itself needs no boiling. The complete installation may still require compression, cooling or gas preparation, so its energy savings depend on the whole system. It can also work alongside existing distillation equipment, recovering material or relieving a bottleneck.
UniSieve’s founders and the challenge of manufacturing membranes
UniSieve was founded in 2018 by ETH Zurich classmates Samuel Hess and Elia Schneider, now chief executive and chief technology officer respectively. Their work involved incorporating porous crystalline materials into polymer membranes.
Molecular sieves already existed, as did industrial membranes. The founders’ challenge was to combine precise separation with the flexibility, durability and manufacturing methods needed for practical equipment.
As with a kitchen sieve, the openings help determine what passes through, but producing that selectivity across an industrial membrane is a demanding materials problem. Defects can allow unwanted molecules through, undermining the separation that worked in a small laboratory sample.
The European Commission’s account of UniSieve’s development describes mechanically stable, flexible membranes compatible with standard cartridges, with pore sizes adjustable for different applications.
UniSieve also supplies the surrounding system, combining equipment, licensing and service. Its proposition reaches from the crystalline material inside the membrane to the connections that bring a unit into operation at a factory.
Industrial trials: from chemical recovery to carbon capture
Developing the material and establishing whether it works in a factory have required successive rounds of manufacturing development and field testing.
Between December 2020 and November 2022, the European Union-funded GREENMEM project helped scale membrane fabrication for initial pilot customers. The Commission reported that pilot testing demonstrated improvements in energy use, costs and product recovery.
An April 2023 seed round raised $5.5 million for further pilots and production capacity. UniSieve said it had already tested its separation technology with industrial partners and secured additional pilot agreements.
Carbon capture then provided a demanding proving ground. In March 2024, the company reported that its “Trift” pilot had extracted carbon dioxide from a Swiss waste-to-energy plant, where its membranes had been deployed throughout 2023.
The trial put the membranes into an operating incinerator’s exhaust stream, testing their resilience beyond controlled laboratory mixtures. UniSieve reported reliable operation, although its announcement did not disclose capture rates, energy consumption or membrane lifetime.
The company now lists more than five demonstration units on its website. Its latest funding announcement describes olefin separation—the chemical family that includes propylene—and point-source carbon capture as having reached pre-commercial maturity.
These applications offer different environmental benefits. Chemical recovery can reduce material losses and separation energy, while carbon capture concentrates CO₂ for subsequent handling. Capturing the gas does not itself prevent its eventual release: the climate outcome also depends on energy use and what happens to the recovered CO₂, including whether it is permanently stored.
What UniSieve’s $9 million Series A will fund
The Series A brings UniSieve’s reported total funding to $25 million. Orano Venture Fund, managed by Supernova Invest, led the round, alongside investors including Amadeus APEX Technology Fund, Founderful, Zürcher Kantonalbank and Guenat Holding.
The money will support wider deployment in existing markets and expansion into additional industrial applications. UniSieve has not disclosed a detailed spending breakdown or production target.
Delivering that expansion means reproducing performance across manufactured membranes and installations; a challenge its competitors are also addressing.
UniSieve’s competitors in gas separation and carbon capture
US-based Ardent Process Technologies, formerly Compact Membrane Systems, targets propylene recovery with Optiperm. Its membranes use facilitated transport, exploiting chemical interactions to help olefins cross the membrane. Ardent reports industrial demonstration with plastics producer Braskem and engineering for a first commercial installation.
In carbon capture, Membrane Technology and Research offers its Polaris polymer membranes. Developed with US Department of Energy support, the platform has been demonstrated at Wyoming’s Dry Fork Station. In April 2026, MTR announced a $27 million investment to accelerate deployment of its industrial separation and carbon capture technologies.
UniSieve’s distinction lies in its crystalline molecular-sieving approach, but the available evidence does not establish that it outperforms these alternatives. Each system must be assessed against the gas mixture, required purity, recovery rate and operating costs of a particular installation.
For plant operators, that comparison also includes the established equipment already on site. A membrane must tolerate the incoming gas, maintain separation performance and last long enough for recovered materials and energy savings to justify its installation and replacement costs.
The practical promise is straightforward: keeping more useful material in circulation while spending less energy separating it. UniSieve’s next stage will show how consistently its molecular precision can deliver those benefits in the everyday running of a factory.
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