Synthesis of Hierarchically Ordered Porous Silica Materials for CO2 Capture: The Role of Pore Structure and Functionalized Amine

Abstract

Hierarchically ordered porous silica materials (HSMs) with a micro/mesoporous structure were successfully prepared with the sol-gel method using dextran, dextran/CTAB, and CTAB as templates. The obtained hierarchically structured silica was successfully modified with amine groups through post-grafting and one-pot methods. Their architectural features and texture parameters were characterized by XRD, N2 adsorption–desorption isotherms, SEM, TEM, FTIR, and TGA techniques. The results demonstrated that the pore structure depended on the reaction temperature and the amount of CTAB added in the synthesis procedure. A series of porous silica with hierarchical pore structures possessed abundant micropores, ordered mesopores, and a tunable surface area and pore volume. After modification, the ordered structure of the hierarchical porous silica almost disappeared due to the presence of amine groups in the pore channel. Furthermore, to explore the effect of pore structures and amine groups on CO2 adsorption performance, before and after amine modification of HSMs, adsorbents were evaluated regarding the capacity of collecting CO2 for comparison. According to these results, the varying microporous content, pore size distribution, and density of the amine groups were important factors determining the capacity of CO2 capture.

Aminosilane-Modified Ordered Hierarchical Nanostructured Silica for Highly-Selective Carbon Dioxide Capture at Low Pressure

“…Such hierarchical porous structures can exhibit characteristics that include interconnected porosity of various length scales, large surface area and pore volumes, enhanced mass transport properties, easily accessible surface sites, selective accessibility, variable chemical composition, and low density, which are highly sought after in energy and gas storage applications. 35,36 Mainly, such materials consist of carbon, yet porous OHNS also possesses ordered macropore arrays with particulate silica in the walls, together with interconnected mesopores from the voids of the sintered silica particles, 37 thus resulting in an interconnected multimode porosity with high potential in adsorption, separation, and catalysis. 36 To the best of our knowledge, there is no report on carbon capture using OHNS-based adsorbents to date.…”

“…Indeed, hierarchical structures have demonstrated advantages of synergistic interactions, high surface area, and multiple functionalities in applications including catalysis, separations, gas sensing and monitoring, environmental and water remediation, and biosensing. , Accordingly, in this work, we combined the robustness of silica with multiporosity via fabricating and functionalizing ordered hierarchical nanostructured silica (OHNS) supports. Such hierarchical porous structures can exhibit characteristics that include interconnected porosity of various length scales, large surface area and pore volumes, enhanced mass transport properties, easily accessible surface sites, selective accessibility, variable chemical composition, and low density, which are highly sought after in energy and gas storage applications. , Mainly, such materials consist of carbon, yet porous OHNS also possesses ordered macropore arrays with particulate silica in the walls, together with interconnected mesopores from the voids of the sintered silica particles, thus resulting in an interconnected multimode porosity with high potential in adsorption, separation, and catalysis . To the best of our knowledge, there is no report on carbon capture using OHNS-based adsorbents to date.…”

A Comparative Loading and Release Study of Vancomycin from a Green Mesoporous Silica

“…Stretching and bending vibrations of surface hydroxyl groups are put into evidence by the existence of a broad peak between 3600 and 3200 cm −1 , as well as a small peak appearing at 1631 cm −1 [ 53 ]. At approximately 1050 cm −1 , we can see the sharp peak that corresponds to asymmetric stretching vibrations of Si-O-Si, complementing the adsorption band at 795 cm −1 , which is characteristic of symmetric stretching vibrations belonging to the same siloxane group [ 54 ]. At 958 and 438 cm −1 , we can see the peaks associated with rocking and stretching vibrations that occur in the Si-O bond of the silanol functional group [ 55 ].…”

Recent Advances on Porous Siliceous Materials Derived from Waste

“…Many studies focus on CO 2 adsorption by porous SiO 2 since CO 2 is the most important “greenhouse” gas derived from the combustion of power plants, metallurgy, cement, chemical production, and human activities, which produces negative effects, such as global warming and the relative environmental consequences [ 216 ]. For this purpose, Xu et al [ 217 ] reported the synthesis of mesoporous SiO 2 from the biomass of a power plant created from a mixture of wheat straw, corn straw, and forestry waste (in 5:2:3 ratio).…”