The energy-intensive process of separating and purifying chemicals and gases is a major reason why industries such as plastics production cause so much pollution. UniSieve aims to reduce their carbon emissions and operational costs with its technology, which uses a high-precision membrane with special crystals that can filter specific molecules and ions.
Today, the Zurich-based startup announced it has raised $5.5 million in seed funding to test and expand its operational capabilities. The round, which UniSieve said was oversubscribed, included participation from the Amadeus Apex Technology Fund, Wingman Ventures, CIECH Ventures and Zürcher Kantonalbank.
UniSieve was founded in 2018 by ETH Zurich classmates Samuel Hess and Elia Schneider. In their work, they developed a way to integrate porous crystals called zeolite materials into polymeric membranes and use them for high-precision filters.
They also discovered how to make production scalable. UniSieve is already making sales and currently has more than 24 customers, including chemical and energy companies. UniSieve is currently focusing on CO2 capture and is also testing applications for separating hydrocarbons (organic compounds made from hydrogen and carbon).
Heavy industries, including plastics, chemical and gas plants, have outdated systems worth billions of dollars, Hess said. This often involves separation and purification processes that require a lot of thermal energy. UniSieve’s modular filters, which Hess compared to Nespresso capsules, can be integrated into existing production systems.

UniSieve’s membrane cartridges
UniSieve stands for “universal sieving” and the technology does not use thermal energy. Instead, the membranes separate chemicals, energy carriers and CO2 from flue gas based on size exclusion. To use another coffee-related metaphor, UniSieve’s membranes are like the coffee filters that keep your drink free of coffee grounds. Like Nespresso or printer manufacturers, UniSieve sells container separation systems and membrane replacement services.
When asked to explain what it means to “integrate zeolite materials into polymeric membranes” in layman’s terms, Hess explained that “it’s like adding special filters to a plastic membrane to make it work better at purifying water, filtering gases and performing other tasks.”
Hess and Schneider originally worked on water treatment membranes before they had their “lightbulb moment.” The two introduced zeolite materials, or porous crystals, into polymeric or plastic-like membranes. Hess explained that zeolites have a well-defined pore structure that can capture or selectively filter certain molecules or ions. When added to polymeric membranes, the combination results in better selectivity, permeability and stability, especially for gas separation.

Team UniSieve
One challenge UniSieve had to solve was that chemicals can vary in size by a fraction of an Angstrom (or one-tenth of a nanometer). This means that the filters must be extremely accurate. Hess said UniSieve’s ability to be fine-tuned means it can be adapted to many different applications, including separating gases other than CO2.
Hess said UniSieve competes with other new technologies such as distillation or amine scrubbing, which use special solvents to remove sour gas. “Compared to such systems, the UniSieve membrane solution is up to 90% more energy efficient and can be used on both a small and large scale. There are a few emerging companies that are also trying to enter the chemical purification market with membranes,” Hess said. “Due to operational constraints, widespread adoption of these competing membranes does not seem realistic.”
In a statement, Lukas Weder, founder of Wingman Ventures, said: “Tried, tested and ready to deploy, the UniSieve technology solution is perfectly positioned to help companies quickly build high-performance energy-efficient manufacturing processes.”