TiO₂ modified magnesium-based adsorbents for intermediate-temperature CO₂ capture

A series of TiO₂-modified magnesium-based sorbents, for thermo-swing absorption process in intermediate-temperature working range (250~500℃), were prepared by precipitation, and characterized by XRD, SEM and N₂ absorption etc. The sorbents were evaluated by dynamic absorption-desorption cyclic tests. With the increase of TiO₂ amount, the crystallinity of the sample decreased, and the BET surface area also decreased due to the formation of MgTiO₃.When the TiO₂ content was 2%, uniform particle size (nanostructured spheres with 4.0~5.0μm in diameter) was obtained. The absorption capacity was stabilized from the second cycle of the absorption-desorption cyclic test, and the capacity could reach 6.64% after 50 cycles, suggesting good stability of the sorbent. This should be attributed to the formation of MgTiO₃, which provided a rigid framework for the sample and improved the dispersion of active species.