SBA-15 mesoporous silica was functionalizedwith polyethylenimine and was used as a substrate for CO2adsorption. The synthesized material, denoted SBA-15-PEI,was characterized by means of X-ray diffraction, thermogravimetricanalysis, and N2 adsorption/desorption at 77 K, inorder to prove that polymer chains efficiently filled the poresof functionalized samples. CO2 adsorption isotherms on SBA-15-PEI were evaluated at T = (298, 313, 328, and 348) K forpressures up to 100 kPa by means of a volumetric technique.The experimental data showed a significant dependence of theCO2 adsorption capacity on temperature, with the highestcapacity encountered at the highest temperature explored.Despite this unusual behavior, CO2 adsorption on SBA-15-PEI was satisfactorily modeled by means of the Sips isotherm. Themodeling effort allowed to evaluate the isosteric heat of adsorption as a function of the fractional coverage of SBA-15-PEI. Thecomparison between the results obtained in the present work and those relative to CO2 adsorption on “benchmark” microporoussubstrates, such as 13X zeolite and Cu-BTC metal organic framework, allowed us to highlight significant analogies and differenceswith those other solids, giving interesting hints on the possible applications of SBA-15-PEI.
|Titolo:||CO2 Adsorption on Polyethylenimine-Functionalized SBA-15 Mesoporous Silica: Isotherms and Modeling|
|Data di pubblicazione:||2014|
|Appare nelle tipologie:||1.1 Articolo in rivista|