Ionic Liquid-based CO$_{2}$ Absorption Technology for Direct Air Capture

Carbon capture is one of the key technologies to combat climate change. Recently, we have presented a new absorption process based on ionic liquids (IL), which allows efficient separation of CO$_{2}$ from various gas streams. Contrary to other approaches, key feature of this process is the regeneration of the solvent at vacuum. Due to the negligible vapor pressure of IL, evaporative loss of solvent is avoided and thermal energy demand for desorption can be lowered.
In the framework of the German research project MethQuest (https://www.methquest.de/en/), we successfully demonstrated continuously capture of CO$_{2}$ from ambient air by a combination of temperature and pressure-swing absorption with IL (see Figure 1). Results from the experimental campaign illustrate that the system shows constant performance over more than 200 h providing CO$_{2}$ with a purity of 92 %. Moreover, we will give detail towards the specific energy demand, which is in the range of state-of-the-art technologies.