Correlation between structural rearrangement of hydrotalcite-type materials and CO2 sorption processes under pre-combustion decarbonisation conditions.

Abstract: Alkali-promoted hydrotalcite-based materials have showed CO₂ sorption capacity up to 1.6 mmol⋅g⁻¹ when CO₂ separation is carried out at relatively high temperature (300–500 °C) and high partial pressure of steam and CO₂, conditions that are prevalent in pre-combustion CO₂ capture conditions. In addition to CO₂ breakthrough experiments in situ XRD experiments have allowed identifying magnesium carbonate crystalline phase formation during CO₂ sorption. The alkali promoted hydrotalcite-based material (Mg/Al ratio 2.9) has revealed that high CO₂ capacities can potentially be achieved by using the extra storage capacity offered by the presence of excess magnesium oxide that can be converted into magnesium carbonate. The use of this extra capacity in Pressure Swing Adsorption process is further discussed. [Copyright &y& Elsevier]