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

The layered double hydroxides (LDHs) of Ca 2+ and trivalent cations, Al 3+ and Fe 3+ , are single-source precursors to generate supported CaO, which picks up CO 2 from the gas phase in the temperature range 350-550 °C. The supports are ternary oxides, mayenite, and Ca 2 Fe 2 O 5 . The uptake capacity of the Fe 3+ -containing LDH at 1.9 mmol g -1 is two times the capacity of the Al 3+ -containing LDH. The product of CO 2 uptake is calcite CaCO 3 . It is observed that the intercalated chloride ions reduce the thermal penalty by inducing the early decomposition of CaCO 3 . In the case of the chloride-intercalated LDHs of Ca 2+ and Fe 3+ , the CaCO 3 formed is completely decomposed at 900 °C. This is in contrast with the CaCO 3 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 CO 2 mineralization.