Adsorption Of Carbon Dioxide And Kinetics On Lithium Silicate Based Adsorbent

Nowdays,energy consumption is still dominated by fossil fuels such as coal,oil and natural gas.On the one hand,due to the non renewable nature of these fuels,their extensive use has created a serious energy crisis;on the other hand,these fossil fuels will produce a large number of pollutants during combustion,including CO₂,SO₂,and soot particles,which cause great harm to human health and environment.Among them,CO₂ has become one of the most important greenhouse gases.In recent years,the greenhouse effect and the environmental problems caused by it have been paid more and more attention;it has become a global problem that restricts the sustainable development of human beings.It is an effective method to control CO₂ emission and reduce the concentration of CO₂ in the atmosphere by trapping and storing CO₂ in a certain way.On the basis of the study of our group,this paper intends to study the influence of the preparation method and metal ion doping on the adsorption performance of lithium silicate adsorbent,the specific contents are as follows:?1?We prepared Li₄SiO₄-based adsorbents by traditional solid method with kaolin-SiO₂ as silicon source,lithium carbonate as the source of lithium and KNO₃ as potassium source,HTNs as aluminum source.Then we investigated the effects of K and Al doping on the adsorption properties of adsorbents.The morphologies and phase composition were analyzed by SEM and XRD.And CO₂ absorption performance was measured with a thermogravimetric analyzer.The experimental results show that the optimal doping amount of K is 0.4 wt.%,and the optimal doping amount of Al is 1.0 wt.%.K and Al co-doped sample 4K10Al-Li₄SiO₄ has the best CO₂ adsorption properties,the maximum adsorption capacity can reach 27.7 wt.%.?2?We prepared Li₄SiO₄-based adsorbents by impregnation-precipitation method with kaolin-SiO₂ as silicon source,lithium nitrate as the source of lithium and KNO₃ as potassium source,while HTNs as aluminum source.and then investigated the effects of K and Al doping on the adsorption properties of adsorbents.The samples were characterized by XRD,NMR and SEM.The experimental results indicate that the optimal doping amount of K is 0.8 wt.%,and the optimal doping amount of Al is 1.5wt.%.K and Al co-doped sample 8K15Al-Li₄SiO₄ has the best CO₂ adsorption properties,the maximum adsorption capacity can reach 32.4 wt.%.?3?The dynamic analysis was carried out by double shell model.And the adsorption process of CO₂ on lithium silicate adsorbent and the effect of doping modification on the adsorption process were discussed.The results show that the diffusion process is the rate controlling step of the adsorption process.Doping K and Al can significantly improve the diffusion rate of lithium...