Innovative CO2 capture using energy-efficient adsorbers

Materials science meets climate protection: Thanks to novel membrane adsorbers, CO₂ can be recovered efficiently and cost-effectively from air and exhaust gases. In the SAFE-CO₂ project, several research institutes – coordinated by the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB – are now pooling their expertise to develop corresponding membrane modules for industry.

Good news for climate protection: The “climate killer” CO₂ can already be removed from the air and recovered today. The catch: The existing processes currently in use require a lot of energy and are therefore inefficient and not very cost-effective. That is why an interdisciplinary research team consisting of the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, the Institute of Polymer Chemistry at Saarland University, and the Center for Solar Energy and Hydrogen Research (ZSW) is now working on an innovative solution that is both environmentally friendly and economically viable. The key to this lies in novel adsorbents.

The challenge: Existing methods and their weaknesses

CO₂ capture can be based on chemical or physical-adsorptive processes. Common methods include flue gas scrubbing for point sources or direct air capture, also known as DAC. However, chemical processes present significant challenges, particularly the high energy requirements for regeneration. This is where the SAFE-CO₂ project partners come in. 

A new approach to more energy-efficient CO₂ capture

The project team led by Dr. Thomas Schiestel, head of the Membranes Group at Fraunhofer IGB, is focusing on developing new thermoresponsive membrane adsorbers that have a high CO₂ capacity, are stable over the long term, and can be regenerated at low temperatures. In doing so, the institute is drawing on its more than 40 years of experience in membrane development.

“Our goal is to develop polymer-based membrane adsorbers as a structured adsorber bed”, explains Tobias Götz, the lead researcher at IGB. “The use of membranes ensures a minimized pressure drop during air flow and thus during CO₂ adsorption. Furthermore, we reduce energy consumption by harnessing the full potential of thermoresponsive CO₂ adsorbers through their integration into an open-pored membrane. This benefits us in two ways – we reduce energy consumption and contribute to the fight against climate change by making recovered CO₂ reusable.”

Intelligent modules with thermoresponsive polymer systems as CO₂ adsorbers

The focus of Götz and his colleagues’ work at the IGB is on developing the porous structures and the module design. The adsorbents used in them come from the Institute of Polymer Chemistry at Saarland University.

“For the membrane modules, we will produce the thermoresponsive CO₂ adsorbents in the form of microgel and core-shell particles”, explains Prof. Dr.-Ing. Markus Gallei.

His area of expertise lies in so-called smart polymers”, i.e., materials that can respond to external stimuli from their environment – such as changes in the solvent, temperature, light exposure, or pH value, as well as mechanical, electrical, or magnetic stimuli.

“The materials we use in the SAFE-CO₂ project react to temperature changes. The resulting thermal phase transition can influence the binding properties of CO₂. This allows them to be used in IGB’s membrane modules as switches between adsorption and desorption to efficiently control CO₂ capture.” 

Another step in the SAFE-CO₂ project is the characterization of the membrane adsorbers used. ZSW in Stuttgart is contributing its expertise to this effort. It focuses on research and development in the field of renewable energy and on supporting the market introduction of new technological developments. ZSW has also been conducting research for more than 30 years on technologies for the direct capture of CO₂ capture from the atmosphere. In addition to developing its own liquid-based DAC technology, ZSW operates the “DACLab”, a test laboratory where various DAC approaches are investigated and evaluated in a technology-neutral manner under a wide range of climatic conditions worldwide. Like the Fraunhofer-Gesellschaft, the center sees itself as a bridge-builder between basic research and industrial practice.

“Our contribution to SAFE-CO₂ consists of extensively testing the materials used and evaluating how environmentally friendly and cost-effective they are compared to existing solutions”, says Dr. Marc-Simon Löffler, head of the renewable energy sources and processes division at ZSW.

Outlook: Long-term contribution to climate protection

The SAFE-CO₂ project, which has now been launched, will run until 2029. By then, the participants aim to demonstrate that direct CO₂ capture from the air is not only technically feasible but can also be achieved with low energy input, and that the developed solution can be used over an extended period.

IGB expert Götz sums it up: “In the long term, we want our technology to help offset unavoidable emissions. In doing so, we aim to focus on sustainable value chains that promote climate-neutral processes and support the transition to a more environmentally friendly economy.”

Funding

The SAFE-CO₂ project is funded by the German Federal Ministry of Research, Technology, and Space (BMFTR) as part of the CDRterra program. This program focuses on reducing CO₂ emissions. The goal is to achieve greenhouse gas neutrality by 2045. To this end, CDRterra supports the development of technologies and processes that permanently remove carbon dioxide from the atmosphere (Carbon Dioxide Removal). The SAFE-CO₂ project receives total funding of approximately 1,260,000 euros.

Source

Fraunhofer-Institute IGB, press release, 2026-06-22.

Supplier

Bundesministerium für Forschung, Technologie und Raumfahrt (BMFTR)
Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik (IGB)
Universität des Saarlandes
Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW)

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