Use of small-amplitude oscillatory shear rheometry to study the flow properties of pure and potassium-doped Li2ZrO3 sorbents during the sorption of CO2 at high temperatures

It has been previously recognized that the addition of lithium/potassium carbonates salts to pure Li2ZrO3 improves significantly the diffusion of CO2 uptake and, consequently, the CO2 sorption capacity. This effect has been associated with the formation of a eutectic molten carbonate layer on the outer surface of the reactant Li2ZrO3 particles. The present work proposes for the first time the use of small-amplitude oscillatory shear (SAOS) rheometry to determine the rheological properties of pure Li2ZrO3 and K-doped Li2ZrO3 under CO2 atmosphere and understand the interplay between these properties and the CO2 absorbed. The results have shown that the rheological parameters (storage modulus, G′; loss modulus, G″; and phase angle, δ) of the samples depend on the type of carbonate mixture and the extent of diffusion and sorption of CO2.