Fossil fuels continue to be major energy sources and the reduction of CO₂ emission from energy production is crucial to the stabilization of greenhouse gas concentration in earth atmosphere.  High temperature sorbents have gained interests because of the energy and cost savings in removing CO₂ at high temperature in processes such as IGCC.  Lithium orthosilicate, or Li₄SiO₄, has been shown to have high CO₂ adsorption capacity and faster kinetics than Li₂ZrO₃ [1].  However, long term stability of the adsorption capacity of Li₄SiO₄ in cyclic operation has not been verified.  Attrition of sorbent particles due to volume expansion upon CO₂ uptake and high mobility of lithium are likely to negative impact the life time of Li₄SiO₄ sorbents.  In this work various porous substrates, such as porous silica, are doped with Li₄SiO₄ and the resulting sorbents, along with unsupported Li₄SiO₄, are tested for both CO₂ capacity and their durability in cyclic adsorption.  Adsorption capacity and kinetics data are presented and the effects of the porous substrates are discussed in terms of both enhanced mass transfer efficiency and sorbent stability.

1. KATO, M., et al., Carbon dioxide absorption by lithium orthosilicate in a wide range

of temperature and carbon dioxide concentrations. JOURNAL OF MATERIALS SCIENCE LETTERS, 2002. 21: p. 485– 487.