Investigation of CO2 adsorption performance of polyethyleneimine charged mesoporous silica materials

Within the scope of the project, the synthesis of amine group impregnated silica materials, which are known to have high CO2 adsorption capacity in gas phase systems, is carried out. The effect of silica support material type (MCM-48 or MSN), calcination state of the support material, surfactant addition to calcined samples and amine group loading ratio (50% and 70% by weight) on the structure of adsorbents are investigated. For the characterization of amine impregnated silica materials, methods such as x-ray diffraction, nitrogen and carbon dioxide sorption, FT-IR spectroscopy, scanning electron microscopy are used. Considering the analyzed samples, it was determined that, despite the preservation of the crystalline structure, a decrease in characteristic plane peak intensities occurred as a result of the penetration of polyethyleneimine into the pores in the support material with the addition of the amine group. However, a decrease in the surface area was observed due to the clogging of the pores as a result of doping polyethyleneimine on the support materials. In scanning electron microscope images in which the morphological structure was examined, it was determined that MSN-based silica support materials had a characteristic rod-like structure, while MCM-48-based materials were spherical in shape and the surface was covered by PEI with amine loading. When the CO2 holding ability of adsorbents as a gaseous pollutant was examined, it was found that the PEI-loaded support materials had low capacity (UC-MCM-48: 0.48 mmol/g, MCM-48: 0.36 mmol/g, UC-MSN: 0.26 mmol/g, C-MSN: 0.50 mmol/g), after the addition of the amine group to the structure, maximum adsorption capacity values for UC-MCM-48-50PEI and UC-MSN-50PEI were obtained as 2.26 mmol/g and 3.31 mmol/g, respectively.