Novel carbon dioxide solid acceptors using sodium containing oxides

The use of solid acceptors for CO2 sequestration has been widely used in many new applications. Recent developments in the field are based in the use of synthetic CO2 acceptors for high-temperature applications (400-700degreesC), which include compounds Such as lithium zirconate (Li2ZrO3) and lithium orthosilicate (Li4SiO4)-Sodium-based oxides have been used in the past either as low-temperature (<250 degrees C) CO2 acceptors or as promoters for lithium-based acceptors. In this study we report the use of Na-based acceptors at high temperatures as an alternative for lithium based CO2 acceptors with the use of thermogravimetric (TGA), and X-ray diffraction (XRD) analysis. Na-based acceptors were prepared by the solid-state method, and the sorption/desorption property prepared included: Sodium titanate (Na2TiO3), sodium antimoniate (Na3SbO4), and sodium zirconate (Na2ZrO3). TGA experiments at 600 degrees C showed Na2ZrO3 to have the highest activity toward CO2 Sorption, followed by Na3SbO4 and Na2TiO3. In the second part of the study Li2ZrO3 and Li4SiO4 were prepared by the solid-state method for comparison purposes. Na2ZrO3 TGA data showed the highest sorption rate at 600 degrees C compared to Li4SiO4 and Li2ZrO3. However. regeneration performance was not as good as LOA and Li2ZrO3. In a two-cycle run Na2ZrO3 presented good sorption and regeneration performance. Experimental data showed that Na-based sorbents can be used as an alternative for solid CO2 acceptors at high temperatures and particularly Na2ZrO3 is a candidate to compete with current synthetic sorbents such as Li4SiO4 and Li2ZrO3 when costs of materials are involved.