Enhancement of CO2 absorption in Li4SiO4 by acidification and eutectic doping

Li4SiO4 absorbent is one of the most promising CO2 absorbents to alleviate the global warming crisis. However, Li4SiO4 absorbents produced by the traditional solid-state method exhibit poor absorption capacity under realistic low CO2 concentrations. In this work, a two-step modification method was carried out involving acidification to enhance the porosity of absorbents and reducing the resistance of gas diffusion through eutectic doping, aiming to produce modified solid-state Li4SiO4 absorbents with superior performance under a low CO2 concentration. The results showed that the conversion of acidified absorbents is 1.5 times higher than the original solid-state absorbents. It was found that the 10 wt % Na2CO3-doped absorbents well maintain a high conversion (>85%) during 20 multiple absorption–desorption cycles (absorption at 550 °C under 15 vol % CO2 for 30 min and desorption at 700 °C under pure N2 for 10 min). It is believed that the greatly improved pore structure by the acidification and the formati...