Dry Carbonate Sorbents for CO Capture from Flue Gases: Role of Support in Adsorption Efficiency and Thermal Stability.

This study presents the results of an investigation of carbonate-containing sorbents for CO capture with natural support materials-kaolin and calcium carbonate-at various loadings of the active phase of NaCO. The effects of the support type on the distribution of the active component, phase composition, and pore structure of the sorbents were studied. It was found that a NaCO loading of 25 wt.% provides the best balance between sorption capacity and technological feasibility. The thermal stability and regeneration capacity of the sorbents were evaluated under high-temperature conditions, revealing high thermal stability of the NaCO/CaCO system up to 1000 °C, along with its durability over multiple adsorption-desorption cycles. Kinetic studies on the NaCO/CaCO sorbent using the shrinking core model demonstrated that the overall CO chemisorption process is controlled by surface chemical reaction at temperatures below 50 °C. The obtained results demonstrate the high potential of CaCO-based sorbents for practical applications in low-temperature CO capture technologies. A promising direction for the use of such sorbents within CCUS is the development of integrated systems, where CO capture is combined with its conversion into valuable products (e.g., methane, methanol, formic acid) through catalytic processes.