Synthesis of functionalized mesoporous silica and its performance for CO2 adsorption

Mesoporous silica was synthesized with the mixture of cationic cetyltrimethylammoium bromide (CTAB) and anionic water-soluble sodium polyacrylate (NaPAA) as template at room temperature, and was further modified with polyethyleneimine (PEI) or magnesium nitrate to get PEI-loaded or MgO-loaded mesoporous silica adsorbents for CO2. The physical properties and CO2 adsorption capacity of as-prepared adsorbents were determined by X-ray powder diffraction (XRD), N2 adsorption-desorption, CO2 static adsorption and temperature programmed desorption. The results indicated that the mesoporous silica possessed high specific surface area, large pore volume and uniform pore structure. The modifiers of PEI and MgO were uniformly dispersed in the channels of the modified mesoporous silica. The adsorption capacities of the PEI-loaded and MgO-loaded mesoporous silica adsorbents for CO2 were enhanced significantly. The highest CO2 adsorption capacity of PEI-loaded mesoporous silica was achieved at 16.7% PEI loading, while an MgO loading of 20% gave the MgO-loaded mesoporous silica the highest CO2 adsorption capacity.