Novel Carbon Dioxide Solid Acceptors Using Sodium Containing Oxides

Abstract

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 (400–700°C), 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°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 was examined by TGA. In the first part of the study sodium acceptors prepared included: Sodium titanate (Na₂TiO₃), sodium antimoniate (Na₃SbO₄), and sodium zirconate (Na₂ZrO₃). TGA experiments at 600°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°C compared to Li₄SiO₄ and Li₂ZrO₃. However, regeneration performance was not as good as Li₄SiO₄ 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.

Keywords:

• CO₂ sorbent
• High temperature CO₂ sequestrian
• NaZrO₃
• Na‐based CO₂ absorbent

Acknowledgments

This research was supported by Consejo Nacional de Ciencia y Tecnología (CONACYT‐México) and Centro de Investigación en Materiales Avanzados (CIMAV) under contract 40118‐Y. The help of Virginia Collins during the technical revision of the manuscript is gratefully appreciated.