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Unexpected Highly Reversible Lithium-Silicate-Based CO₂ Sorbents Derived from Sediment of Dianchi Lake

Wang, Junya, Zhang, Taiping, Yang, Ying, Li, Min, Qin, Qingqing, Lu, Peng, Ning, Ping, Wang, Qiang
Energy & fuels 2019 v.33 no.3 pp. 1734-1744
carbon dioxide, fuels, hydrochloric acid, lakes, leaching, lithium, nitrates, nitric acid, sediments, silica, sorbents, sorption, temperature, thermogravimetry
In this work, Li₄SiO₄-based sorbents synthesized from sediment of Dianchi Lake for CO₂ capture are reported for the first time. The sediment of Dianchi Lake was leaching treated with different ratios of hydrochloric acid (HCl) and nitric acid (HNO₃), from which obtained SiO₂ was used for synthesis of Li₄SiO₄-based sorbents. The sorbents were all prepared by a solid-state reaction method using lithium nitrate (LiNO₃, analytical reagent grade) and obtained SiO₂, and their CO₂ capture performances were determined using a thermogravimetric method by a thermogravimetric analyzer. Influences of some important parameters, such as pretreatment conditions, synthesis conditions, and sorption conditions, on the CO₂ uptake capacity of Li₄SiO₄-based sorbents were thoroughly investigated. The results showed that sediment-derived Li₄SiO₄ exhibited the largest CO₂ uptake capacity of 27.93 wt %, reaching 76% of the theoretical value of 36.70 wt %. More importantly, it showed outstanding cycling stability and superior regeneration ability in both temperature swing sorption and pressure swing sorption procedures, which will have high potential for a practical high-temperature CO₂ sorbent.