Canadian Journal of Chemical Engineering, Vol.98, No.7, 1495-1500, 2020
High-temperature CO2 adsorption over Li4SiO4 sorbents derived from different lithium sources
Li4SiO4 is a promising sorbent for high temperature CO2 capture. It could be synthesized from three different Li sources (LiNO3, LiOH, and Li2CO3) by using the solid state reaction method. The effects of Li sources on the structure and CO2 adsorption/desorption properties of Li4SiO4 sorbents were analyzed in this work. The results showed that Li4SiO4 sorbents could be synthesized at a lower temperature by using LiNO3 and LiOH as the starting materials, which could reduce the sintering during the synthesis process and increase the surface area of synthesized Li4SiO4. During the CO2 adsorption/desorption cycles, Li4SiO4 sorbents derived from LiNO3 and LiOH presented higher initial CO2 adsorption capacities than those from Li2CO3. After 15 cycles, the adsorption efficiency of Li4SiO4 derived from LiNO3 showed no or slight decrease, while that from LiOH rapidly decreased to 20% of the initial value. This was because Li4SiO4 derived from LiNO3 had high surface area and porosity before CO2 adsorption/desorption cycles, and its surface area even increased after cycles. However, the surface area of Li4SiO4 derived from LiOH decreased greatly due to serious sintering. For Li4SiO4 derived from Li2CO3, its morphology and surface area were almost unchanged before and after CO2 adsorption/desorption cycles.