Study On The Preparation And CO₂ Adsorption Of MgO Modified Mesoporous Materials

As one kind of key greenhouse gas, carbon dioxide with its increasing high emission is changing human's living environment. Mesoporous silica has been studied and applied in carbon dioxide capture field for its high surface area and uniform pore size distribution. Now the researches on carbon dioxide adsorption capacity of mesoporous silica focused mostly on incorporating amino groups, however the hydro-thermal stability doesn't satisfy the requests of industrial applications. As a typical acidic gas, it is likely to increase the carbon dioxide adsorption capacity of material by adding basic sites on mesoporous silica. In this paper the magnesium oxide modified mesoporous silicawas synthesized to increase its carbon dioxide adsorption capacity.Mesoporous silica was synthesized in acidic condtion by using triblock copolymer P123 as template and TEOS as silica source. XRD TEM and N2 adsorption-desorption analysis were used to characterize the structure of the material. It is shown that the synthesized material owns high surface area and uniform pore size, which are typical characteristics of mesoporous material. The magnesium oxide modified materials were synthesized by one-step method and impregnating method, separately. The structure and carbon dioxide adsorption capacity of the samples were studied.N2 adsorption-desorption isotherms indicate that the modified samples possess typical mesoporous material structure. Comparing with the original mesoporous material, the surface area and pore volume of the MgO modified sample synthesized by impregnating decrease, while the average pore size increases. The capacity of carbon dioxide adsorption for the modified material is higher than the original mesoporous materials, which indicates that magnesium oxide is benefical for the capacity of carbon dioxide adsorption. The surface area, pore volume and average pore size of the modified material synthesized by one-step method increase than the original mesoporous material, which is helpful to improve the adsorption capacity. The capacity of carbon dioxide adsorption is obvious higher than the original mesoporous material. In a word, the introduction of magnesium oxide is conductive to increase the capacity of carbon dioxide adsorption.