(159e) Densitiy Funtional Theory Study of CO2 Sequestration On Magnesium-Based Adsorbents

Formation of permanent surface carbonates using alkaline-earth elements is promising mechanism for CO2 sequestration because this method can prevent potential leakage after sequestration. Although for this surface carbonation, CO2 molecules should be bound on the surface of metal oxides such as calcium and magnesium oxides, normally such metal oxides are bound to a silicate mineral such as calcium silicate and magnesium silicate. In this study, we apply density functional theory (DFT) to investigate the structure and the adsorption energy of CO2 on magnesium-rich silicates such as olivine (Mg2SiO4) that has been known to provide high reactivity with low cost. For this, the crystal structure of olivine is simulated and compared to the experimental structure, and then olivine (001) surface is generated. Once the geometry-optimized olivine surface is prepared, CO2 molecules are adsorbed to specify the probable adsorption site and adsorbed geometry. DFT calculations are performed using Dmol3 with GGA PBE and DND basis set. The adsorption mechanism will be presented at various conditions such as CO2 surface coverage and surface morphology.