Influence of the K‐, Na‐ and K‐Na‐carbonate additions during the CO₂ chemisorption on lithium oxosilicate (Li₈SiO₆)

Abstract

Lithium oxosilicate (Li 8 SiO 6 ) was synthesized and mechanically mixed with potassium carbonate, sodium carbonate, or a mixture of both. While the product sample composition was characterized using X-ray diffraction, the CO 2 chemisorption was evaluated using dynamic (30-800 °C), isothermal (350-650 °C) and cyclic thermogravimetric analyses. The presence of the K, Na, or K-Nacarbonates in Li 8 SiO 6 changes the sorption properties in a wide temperature range. K-, Na-, K-NaLi 8 SiO 6 samples captured a maximum weight of 32 wt% at 400 °C, 42 wt% at 550 °C, and 38 wt% at 600 °C, respectively. The results revealed that the weight gained on Li 8 SiO 6 mixed with K-, Na-and K-Na-carbonates was attributed to the formation of the eutectic phases. These materials would be suitable for CO 2 capture over a wide temperature range depending on the application process. Nevertheless, the cyclic experiments showed important variations in their respective effi ciencies, depending on the temperature.

CO2 chemisorption and cyclability analyses in α−Li5AlO4: effects of Na2CO3 and K2CO3 addition

“…At these temperatures, the final weight increases were 11.2 and 11.5 wt%, respectively. A similar isothermal behavior had been already reported on the K‐doped Li 8 SiO 6 in the same temperature range . In that case, the explanation given to the isotherms was as follows.…”

“…Some of the lithium ceramics, previously mentioned, have been doped adding different carbonates such as K 2 CO 3 , Na 2 CO 3 , MgCO 3 and CaCO 3 . The addition of these carbonates favors the formation of eutectic phases on the carbonate external shell, improving the CO 2 chemisorption kinetics and efficiencies, compared with their respective alkali pure ceramics – . Thus, the aim of the present work was to produce K‐ or Na‐doped Li 5 AlO 4 samples, as these mixtures would improve the CO 2 chemisorption rates due to the Li 2 CO 3 ‐K 2 CO 3 or Li 2 CO 3 ‐Na 2 CO 3 eutectic phase formations, resulting in a partial molten shell that facilitates the CO 2 diffusion throughout the external shell.…”

Fabrication of Lithium Silicates As Highly Efficient High-Temperature CO2 Sorbents from SBA-15 Precursor

“…In addition, Li 8 SiO 6 (Li-SBA15-10) synthesized from the SBA-15 precursor also resulted in a higher CO 2 uptake (62.0 wt %) comparing to previous literature reports. 14,24 Therefore, these two excellent sorbents, Li-SBA15-4 and Li-SBA15-10, were further comprehensively investigated in the following sections.…”

Performance of Li4SiO4 Material for CO2 Capture: A Review

“…In the process of CCS, CO 2 is captured from flue gas and stored for utilization and sequestration instead of being released to the environment directly. Recent studies have found that various lithium-based materials, such as LiFeO 2 [6], Li 2 CuO 2 [7], Li 2 ZrO 3 [7,8,9], Li 8 SiO 6 [10,11], and Li 4 SiO 4 [9], are capable of effective CO 2 capture. Among these materials, Li 4 SiO 4 , with a variety of applications [12,13], has better application potential, owing to its higher CO 2 sorption capacity, cyclic stability than LiFeO 2 , Li 2 CuO 2 , and Li 8 SiO 6 , and lower cost than that of Li 2 ZrO 3 [9].…”