CO 2 chemisorption and cyclability analyses in α−Li 5 AlO 4 : effects of Na 2 CO 3 and K 2 CO 3 addition

Lithium aluminate (α−Li 5 AlO 4 ) was synthesized and mixed with potassium carbonate or sodium carbonate. The addition of these alkaline carbonates was produced during or after the synthesis process. The CO 2 chemisorption was evaluated using dynamic, isothermal, and cyclic thermogravimetric analyses. The presence of the K or Na in α−Li 5 AlO 4 changes the sorption properties in a wide temperature range. K‐ and Na‐Li 5 AlO 4 samples, when the alkaline carbonates were added 10 wt% presented better CO 2 capture properties, capturing 37−39 wt% at 660 °C and ∼50 wt% at 710 °C, for doped samples prepared mechanically or synthetically, respectively. The results revealed that the weight gained on α−Li 5 AlO 4 mixed with K‐ or Na‐carbonates was attributed to the formation of the eutectic phases. These materials would be suitable for CO 2 capture over a wide temperature range depending on the application process. Nevertheless, the cyclic experiments showed important variations in their respective efficiencies, depending on the temperature. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd