Preparation of Li4SiO4 Sorbents for Carbon Dioxide Capture via a Spray-Drying Technique

Various synthesis methods, such as the combustion method, sol–gel method, impregnated suspension, precipitation, etc., have been previously proposed for the production of efficient Li4SiO4 sorbents. During these methods, the mixture of the precursors of Li and Si were usually dried through the oven, water bath, or oil bath, which are all energy-consuming and slow processes. To produce Li4SiO4 sorbents quickly and efficiently, the spray-drying technique was employed in this work. The spray-dried sorbents exhibited both excellent CO2 capture capacity and cyclic stability during the multiple cycles, indicating that the spray-drying method was effective for the preparation of efficient and durable Li4SiO4 sorbents for high-temperature CO2 removal. Especially, the sorbent using lithium tartrate as the Li source achieved a considerable first-cycle CO2 sorption capacity of ∼0.275 g of CO2/g of sorbent and still held the capacity of ∼0.248 at the 50th sorption/desorption cycle under the realistically low CO2 concentration of 15 vol %. The excellent performance of the sorbent was demonstrated to be attributed to the corresponding small crystallite size of Li4SiO4, high surface area, large pore volume, and rich porosity.