Development of Alkali Nitrate-Containing Li4SiO4 for High-Temperature CO2 Capture

High efficiency alkali nitrate-containing Li 4 SiO 4 sorbents were synthesized by a hydration technique to improve their sorption performances at low CO 2 concentrations. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and thermogravimetric analyses were used to detect the characteristics of the samples. The results showed that the presence of KNO 3 and NaNO 3 induced small crystallite size, corrugated morphologies and the formation of eutectic phases, noticeably facilitating sorption processes. At the optimized additive amount of 0.035 mol %, NaNO 3 -containing Li 4 SiO 4 reached a maximum absorption capacity (≈34.6 wt %). Moreover, both alkali nitrate-containing Li 4 SiO 4 sorbents showed good cyclic properties, demonstrating their great potential for high-temperature CO 2 capture.