CO2 Sorption Properties of Nano-Sized Zirconia-Based Sorbents Promoted with Alkali Metal Carbonates

To investigate the CO2 sorption and regeneration properties of Zr-alkali metal sorbents for CO2 capture from flue gas at a temperature range of 30 degrees C to 150 degrees C, various sorbents were prepared by impregnating commercial or nano-sized zirconium oxide (ZrO2) with sodium carbonate (Na2CO3) or potassium carbonate (K2CO3). Commercial Zr-potassium sorbent (KZr(C)I30) had a very low CO2 sorption rate but excellent regeneration properties. On the other hand, a new nano-sized Zr-potassium sorbent (KZr(S)I30), which was made using ZrO2 prepared by sol gel method as a support, had an enhanced CO2 sorption rate due to an improved textural properties of the sorbent. In the case of sodium carbonate, the CO2 sorption rate of the nano-sized Zr-sodium sorbent (NaZr(S)I30) was considerably less than that nano-sized Zr-potassium sorbent (KZr(S)I30) despite a high CO2 capture capacity. Nonetheless, all Zr-based sorbents promoted with alkali metals showed excellent CO2 capture capacities without deactivation due to the exclusive formation of alkali metal bicarbonates without any other by-products.