Effect of K2CO3 doping on CO2 sorption performance of silicate lithium- based sorbent prepared from citric acid treated sediment

In this paper, a low-cost and environmental-friendly leaching agent citric acid (C6H8O7) was used to treat the sediment of Dianchi Lake (SDL) to synthesize lithium silicate (Li4SiO4) based CO2 sorbent. The results were compared with that treated with strong acid. Moreover, the effects of preparation conditions, sorp-tion conditions and desorption conditions on the CO2 sorption performance of prepared Li4SiO4 were sys-tematically studied. Under optimal conditions, the Li4SiO4 sorbent was successfully synthesized and its CO2 sorption capacity reached 31.37% (mass), which is much higher than that synthesized from SDL trea-ted with strong acid. It is speculated that the presence of some elements after C6H8O7 treatment may pro-mote the sorption of synthetic Li4SiO4 to CO2. In addition, after doping with K2CO3, the CO2 uptake increases from the original 12.02% and 22.12% to 23.96% and 32.41% (mass) under the 20% and 50% CO2 partial pressure, respectively. More importantly, after doping K2CO3, the synthesized Li4SiO4 has a high cyclic stability under the low CO2 partial pressure.(c) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.