Study On Modified Silicon-based Mesoporous Materials For CO₂Adsorption And Capture

Many scientific reports show that human intervention has caused Earth’s currenttemperature and climate changes, and this is a matter of immense concern. TheReports by Intergovernmental Panel on Climate Change （IPCC） suggest that CO₂isthe most important greenhouse gas due to its greatest effect on global warming andclimate changes. CO₂Capture and Storage is one of the most effective measures forgreenhouse carbon oxide emission reduction.The mean body of this paper aims to research capture and separation CO₂usingmodified silicon-based mesoporous materials through adsorption method. By way ofX ray photoelectron spectroscopy （XPS）, X ray diffraction （XRD）, energy dispersivespectrometer （EDS）, transmission electron microscope （TEM） and scanning electronmicroscope （SEM）, the analysis result of experiments indicated that acetic acid leadimpregnated on a silicon surface into PbO by roasting. In this study, CO₂adsorption inthe presence and absence of H2O was investigated on different modified silicon-basedmesoporous materials including lead oxide modified silica gel （PbO/Silica gel）, leadoxide modified SBA-15（PbO/SBA-15）, as well as lead oxide modified MCM-41（PbO/MCM-41）. It is shown that the reason these modified silicon-based mesoporousmaterials adsorb CO₂is that there is a chemical reaction tetween CO₂and PbO scattedon the silica-based mesoporous materials at the existence of water, and the CO₂adsorption quantity is proportional to the amount of and PbO. In the experiments themaximum CO₂adsorption amount of three adsorbents inculuding PbO/Silica gel,PbO/SBA-15and PbO/MCM-41reached to240.86mg·g^-1,229.89mg·g^-1and273.93mg·g^-1respectively. The results show that, with the increasing of PbO loaded.Modified silicon-based adsorbents can adsorb more CO₂, but at the longer timerequired to reach adsorption equilibrium, which will be meanless for caputre CO₂rapidly. The study shows that lead oxide modified silicon-based porous materialscapture CO₂fastest when PbO dispersed as a monolayer, meanwhile, the equilibriumCO₂adsorption capacity of PbO/Silica gel, PbO/SBA-15and PbO/MCM-41is116.38mg·g^-1,163.54mg·g^-1and184.79mg·g^-1respectively.The CO₂concentration that is over2%in enclosed chamber will be unsuitablefor healthy.13.03%of the CO₂content of the raw gas is uesd to test penetration experiment in modified silicon adsorbents. The result shows these three kinds ofadsorbents, PbO/Silica gel, PbO/SBA-15and PbO/MCM-41, can make CO₂concentration of gas mixture under2%for a long time in the water vapor condition,and the CO₂adsorption capacity of gas mixture by these three adsorbents is58.4mg·g^-1,80.6mg·g^-1and102.2mg·g^-1respectively, which indicates the adsorbentsprepared by this method can not only rapidly adsorb pure CO₂gas, but also cancapture CO₂from low carbon content of mixture and they are new adsorbents beingapplied to capture CO₂in enclosed chamber.Chemical adsorbent is always much harder to be regenerated. In this paper, thesilica-based-functionalized adsorbents that adsorbed maximumly can be regeneratedat380℃for3hours under the protection of nitrogen. It is found that regeneratedabsorbents have a good effect of adsorption for capture and store carbon dioxide afterseveral cyclings. So lead oxide modified silicon-based porous materials are ideal CO₂capture and separation adsorbents.