Preparation, characterization of Ca/Al carbonate pellets with TiO2 binder and CO2 sorption at elevated-temperature conditions

High-temperature CO2 capture using a Ca/Al carbonate sorbent, made of Ca–Al–CO3 powder and a TiO2 binder, was studied. Calcium aluminates were synthesized by the coprecipitation of Ca2 +, Al3 +, and CO32 − under alkaline conditions. The results showed that TiO2 nanoparticles significantly improved surface area and cyclic stability of sorbents in thermogravimetric analysis (TGA) and reactor. Six types of Ca / Ti pellets were prepared, using a Ca–Al–CO3/TiO2 weight ratio of 1–6:1. These granules gave a very stable CO2 uptake, to 80% of their full capacity, for 10 cycles, compared to only 35% using Ca–Al–CO3. A possible reaction scheme for stabilizing the CaO microstructure for multi-cycle experiments is described.