CO2 Separation by a New Solid K−Fe Sorbent

Abstract

An inexpensive K−Fe-based sorbent using K2CO3 and nanoporous FeOOH was developed, and its CO2 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 CO2 capture capability by more than 70 times compared to pure K2CO3. The sorption capacity of the K−Fe sorbent reaches its peak when its K2CO3 content is 33.33 wt %, under the tested sorption conditions. The CO2 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 CO2 capture capability of the K−Fe sorbent is ∼49 mg of CO2/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 CO2/g of sorbent when the regeneration temperature is 125 °C. Catalysis plays an important role in improving CO2 desorption, thus reducing the energy required for the CO2 separ...