Wet ball-milling method to prepare nanocrystalline Li₄SiO₄ materials for CO₂ capture at high temperatures

A wet ball-milling method followed by calcination was adopted to prepare nanocrystalline Li₄SiO₄ materials by using different silicon and lithium sources. X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) were applied to characterize the structure and morphology of the as-prepared Li₄SiO₄ materials. CO₂ uptakes and recycle stability of the prepared Li₄SiO₄ materials were investigated on a thermogravity (TG) analyzer. Absorption equilibrium of 27.9% was achieved within 10 min at 550℃ and CO₂ partial pressure of 2.5×10⁴ Pa. The prepared nanocrystalline Li₄SiO₄ material kept the original absorption properties after 5 capture-regeneration cycles, indicating the good cycle stability. A mixture of 25% CO₂-25% N₂-50% He was introduced through the Li₄SiO₄ absorption bed, showing that CO₂ can be efficiently captured at 550℃. The adsorption capacity showed no significant decrease in the presence of 10% humidity.