Novel Low-Temperature K2CO3-based Composite Sorbents for Direct CO2 Capture from Ambient Air
It is well known that CO2 is the major anthropogenic greenhouse gas, which contributes to global climate change. Potassium carbonate is a solid inorganic chemisorbent, which reacts with atmospheric CO2 in the presence of water vapor forming potassium bicarbonate. However, bulk potassium carbonate is not widely used as a material for CO2 capture due to low reaction rate and insufficient mechanical strength. These problems can be solved by dispersing K2CO3 in pores of a support material. Recently, it was shown that K2CO3/-Al2O3 composite is a promising material for absorbing CO2 directly from ambient air [1-4]. However, this material needs to be heated up to 300oC in order to be fully regenerated due to interaction between the active component and the porous support, which results in formation of potassium dawsonite KAlCO3(OH)2 [1, 2]. In this work we report the preparation and properties of K2CO3-based composite sorbents of atmospheric CO2 which can be efficiently regenerated at T=150-200C. Relations between phase composition of the composite sorbents and their CO2 sorption/desorption properties will be analyzed. We will also discuss the effect of relative air humidity on CO2 absorption capacity of the composite materials. The results of testing the performance of the composite sorbents under conditions of temperature-swing adsorption cycling will be presented as well.
The study was supported by Russian Science Foundation (project № 17-73-10068).