Sol-gel Synthesis of MgAl2O4-stabilized CaO for CO2 Capture

Ca-based, MgAl2O4-stabilized sorbents for CO2 capture were prepared using a sol-gel approach. The chemical composition and morphology of the sorbents were characterized using scanning electron microscopy, X-ray diffraction and N2 adsorption analysis. The cyclic CO2 uptake of the materials was studied in a thermogravimetric analyzer and fluidized bed reactor. It was found that the calcium precursor and condensation catalyst strongly influenced the chemical composition and morphology of the sorbents and, in turn, their cyclic CO2 uptake capabilities. The material that was synthesized using Ca(CH3COO)2 as the calcium precursor and acetic acid as a condensation catalyst possessed the highest cyclic CO2 uptake, viz. 0.39 g CO2/g sorbent after 10 cycles of calcination and carbonation, a value that compares favorably to the CO2 uptake of the reference limestone of 0.18 g CO2/g sorbent.