日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

There is an urgent need to reduce the concentration of carbon dioxide (CO₂) in the atmosphere as part of the measures to combat global warming. It is essential to reduce CO₂ emissions to prevent further increases in CO₂ concentration. However, it is impossible to capture CO₂ from all sources of CO₂ emissions. Therefore, direct air capture (DAC) of CO₂ from the atmosphere is also indispensable. This paper outlines both the reduction of CO₂ emissions and the direct capture of CO₂ from the atmosphere. First, the current issues regarding CO₂ capture technologies are introduced and membrane separation, which has recently attracted attention as a promising CO₂ capture technology, is highlighted. In this context, the CO₂ capture using “free-standing nanomembranes”, which we are promoting, is introduced. Considering the strong need for DAC technologies, this paper discusses the development of freestanding and nanometer-thick membranes for DAC and the current status of membrane performance improvement. Finally, the future potential of membrane-based DAC (m-DAC) is discussed.