Abstract
DAC (Direct Air Capture) refers to low concentrations of CO2 in the atmosphere (about 400 ppm). In general, there are both physical adsorbents and chemical absorbers for high–concentration CO2 recovery materials for exhaust gas, however since DAC requires CO2 to be captured under extremely low CO2 partial pressure, zeolite and activated carbon, which are general physical adsorbents, have low CO2 capture efficiency and are not suitable as DAC materials. The author has found that sodium ferrite NaFeO2 promotes the reaction with CO2 in the air at room temperature in the presence of water vapor, and has proposed that its properties can be applied as a CO2 absorbing material in the air. In this paper, I also introduce the CO2 absorption characteristics of sodium manganate, which can be DAC by the same mechanism as sodium ferrite, and layered double hydroxide, which has a layered structure.
