Interaction of Pristine Hydrocalumite-Like Layered Double Hydroxides with Carbon Dioxide.

ABSTRACT

The layered double hydroxides (LDHs) of Ca2+ and trivalent cations, Al3+ and Fe3+, are single-source precursors to generate supported CaO, which picks up CO2 from the gas phase in the temperature range 350-550 °C. The supports are ternary oxides, mayenite, and Ca2Fe2O5. The uptake capacity of the Fe3+-containing LDH at 1.9 mmol g-1 is two times the capacity of the Al3+-containing LDH. The product of CO2 uptake is calcite CaCO3. It is observed that the intercalated chloride ions reduce the thermal penalty by inducing the early decomposition of CaCO3. In the case of the chloride-intercalated LDHs of Ca2+ and Fe3+, the CaCO3 formed is completely decomposed at 900 °C. This is in contrast with the CaCO3 formed from bare CaO, which shows no sign of decomposition at 900 °C under similar conditions. This work shows that the hydrocalumite-like LDHs are candidate materials for CO2 mineralization.