NaNO2/MgO/titania spheres prepared via aerosol-assisted self-assembly (AASA) were used as sorbents for CO2 adsorption at moderate temperature. The titania framework as support would allow MgO to disperse well, thereby increasing the contact between MgO and NaNO2 to enhance carbonation. In this study, the effect of Mg/Ti molar ratio and NaNO2 addition amount on CO2 adsorption was investigated. Results showed that the sorbent prepared by AASA with Mg/Ti molar ratio of 2 following the introduction of 30 wt% NaNO2 presented ∼1 μm particle size with rough sphere surface morphology and mesoporous properties, where the surface area and pore volume were 72 m2/g and 0.18 cm3/g, respectively. With NaNO2 addition, the kinetics and capacity of CO2 adsorption significant increased. In the cyclic adsorption/desorption experiment, the superior stability over the NaNO2/MgO/titania spheres was mainly ascribed to the confined space suppressed the degree of the sintering effect. These results indicated the potential application of the nanochannel-restricted sorbent for rapid, high-capacity, and stable CO2 capture at moderate temperatures.
Keywords: CO2 capture; MgO; NaNO2; molten salts; titania.