CO2 Separation by a New Solid K−Fe Sorbent

An inexpensive K−Fe-based sorbent using K 2 CO 3 and nanoporous FeOOH was developed, and its CO 2 separation performance was investigated in a fixed-bed tube reactor under differing conditions. Because of its high surface area and porous structure, FeOOH can increase CO 2 capture capability by more than 70 times compared to pure K 2 CO 3 . The sorption capacity of the K−Fe sorbent reaches its peak when its K 2 CO 3 content is 33.33 wt %, under the tested sorption conditions. The CO 2 sorption capacity of the sorbent increases with an increase of moisture in gas but decreases dramatically with the elevation of the sorption temperature. The total CO 2 capture capability of the K−Fe sorbent is ∼49 mg of CO 2 /g of sorbent at 60 °C in a 10 vol % moisture environment. The sorbent is regenerable, and its multicycle sorption capacity remains at ∼30 mg of CO 2 /g of sorbent when the regeneration temperature is 125 °C. Catalysis plays an important role in improving CO 2 desorption, thus reducing the energy required for the CO 2 separation technology.