Experimental study on Li₄SiO₄ adsorption capability for CO₂ capture

Li₄SiO₄ used as a revolving CO₂ absorbent at determinate temperature can be synthesized with SiO₂ and Li₂CO₃ by solid state reaction at high temperature. The crystal structure and microstructure of Li₄SiO₄ were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The CO₂-adsorption capability of Li₄SiO₄ was studied by TGA preliminarily, and then was tested in a small experimental apparatus. The results show that the CO₂-adsorption capability is influenced by the preparation temperature of Li₄SiO₄ synthesis, and it was the largest at 700 ℃. The maximum adsorption capability could achieve 34%. Besides, the adsorption capability increases as the adsorption temperature going up and longer time. When CO₂ concentration was 75%, 67%, 60%, the adsorption capability could respectively reach 6.68 mmol/g, 3.37 mmol/g, 2.02 mmol/g.