The capture of carbon dioxide by transition metal aluminates, calcium aluminate, calcium zirconate, calcium silicate and lithium zirconate

Abstract

The capture of CO 2 by transition metal (Mn, Ni, Co and Zn) aluminates, calcium aluminate, calcium zirconate, calcium silicate and lithium zirconate was carried out at pre-and post-combustion temperatures. The prepared metal adsorbents were characterized by Xray diffraction (XRD), scanning electron microscope (SEM), surface area analysis and acidity/alkalinity measurements. The different experimental variables affecting the adsorbents ability to capture CO 2 , such as the mol ratio of metal ions, the pressure of CO 2 , the exposure time and the temperature of the adsorbent were also investigated. Calcium zirconate captured 13.85 wt-% CO 2 at 650°C and 2.5 atm and calcium silicate captured 14.31 wt-% at 650°C. Molecular sieves (13X) and carbon can only capture a negligible amount of CO 2 at high temperatures (300°C-650°C). However, the mixed metal oxides captured reasonable amount of CO 2 at these higher temperatures. In addition, calcium aluminate, calcium zirconate, calcium silicate and lithium zirconate adsorbents captured CO 2 at both pre and post-combustion temperatures. The trend for the amount of captured carbon dioxide over the adsorbents was calcium aluminate < lithium zirconate < calcium zirconate < calcium silicate.

Thermodynamic and Kinetic Analyses of the CO2 Chemisorption Mechanism on Na2TiO3: Experimental and Theoretical Evidences

“…Among these materials, different alkaline ceramics have been reported as good solid candidates for CO 2 sorbents in terms of large CO 2 sorption capacity and high operating temperatures. − Some of the alkaline ceramics most studied are lithium silicates (Li 8 SiO 6 , Li 4 SiO 4 , and Li 2 SiO 3 ), − lithium zirconates (Li 8 ZrO 6 , Li 6 Zr 2 O 7 , and Li 2 ZrO 3 ), …”

Sodium-promoted iron catalysts prepared on different supports for high temperature Fischer–Tropsch synthesis

“…Indeed, a new broad band appears at 1090 cm −1 which might be assigned to symmetric stretching bands of carbonates [33]. This might be a result of the strong interaction of iron with alumina leading to the aluminates which have strong ability to capture CO 2 [34]. The presence of sodium also results in the appearance of addi- tional bands at 1078, 984 and 884 cm −1 , which might be explained by the formation of surface sodium carbonates [32].…”

Lithium and calcium based perovskite type oxides for ethylic transesterification

“…However, the CO 2 vibration peaks are observed in the spectrum at 1620-1500 cm −1 , corresponding to C O bond [38,42], most notably for Li 2 ZrO 3 and CaLiZrO 3 oxides. Some studies have found that Li 2 ZrO 3 is a good adsorbent of CO 2 [42][43][44]. In these studies, a mechanism of reaction at high temperature proposes the formation of Li 2 CO 3 on the surface and a dense ZrO 2 shell in the middle covering the unreacted Li 2 ZrO 3 .…”

“…In these studies, a mechanism of reaction at high temperature proposes the formation of Li 2 CO 3 on the surface and a dense ZrO 2 shell in the middle covering the unreacted Li 2 ZrO 3 . The effects of CO 2 sorption promote the Li + and O 2− formation in the reversible reaction with Li 2 ZrO 3 [42][43][44]. Therefore, the mass changes observed for oxides containing lithium in the TGA at 500-800 • C may be attributed to chemical structural transformations, which occur due to adsorbed atmospheric CO 2 according to FT-IR analysis.…”