Low-cost CO₂ adsorbents based on magnesium-modified hierarchical porous silica

Abstract

A low-cost CO₂ adsorbent was synthesized using a hierarchically porous silica (MAR-22) obtained from industrial-grade precursors. Magnesium modification was carried out by template ion-exchange, resulting in a high dispersion in the material and a final Mg loading of 2.29 wt.%. The modification caused a slight loss of ordering in the structure without significantly compromising the material porosity. Consequently, the Mg-modified material exhibited a higher CO₂ adsorption capacity than the parent silica, reaching 0.89 mmol g^-1 at 1 bar. In conclusion, despite its minor effect on structural ordering, the incorporation of Mg species substantially improves CO₂ adsorption, validating this technique as an efficient alternative for carbon capture technologies.