粉煤灰衍生硅酸锂吸附剂CO2捕集性能研究OA

The consumption of fossil fuels has led to a series of environmental issues due to CO2 emissions,drawing increasing attention to carbon capture and storage(CCS)technology.Lithium silicate(Li4SiO4)is considered a highly promising sorbents due to its high CO2 capture capacity,low regeneration temperature,and good thermal stability.However,its widespread application is limited by the high cost of silicon sources and insufficient cycling performance.Low-cost fly ash was used as silicon source to synthesize Li4SiO4 via solid-state and impregnation-precipitation methods,followed by modification with K2CO3 doping.The materials were characterized by testing methods such as XRF,XRD,and SEM.The results show that the sorbents prepared by the solid-phase method at 700 ℃(LS-700)possesses a rich pore structure and a high specific surface area of 1.584 2 m2/g,and exhibits the optimal sorption performance,with the CO2 sorption capacity remaining at 0.179 7 g/g after 10 cycles.After K2CO3 doping,the CO2 sorption rate increased to 0.054 5 g/(g·min),which is 1.4 times that of the undoped sample.Mechanistic studies revealed that the formation of a low-temperature eutectic layer between K2CO3 and Li2CO3 promoted CO2 diffusion and reduced the reaction activation energy.This study provides an effective strategy for developing low-cost and high-performance Li4SiO4-based sorbents,demonstrating significant value for enhancing CO2 capture efficiency from coal-fired flue gas.