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

Abstract

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 rege...