Main content area

CO2 Adsorption on Amine-Functionalized Periodic Mesoporous Benzenesilicas

Sim, Kyohyun, Lee, Nakwon, Kim, Joonseok, Cho, Eun-Bum, Gunathilake, Chamila, Jaroniec, Mietek
ACS Applied Materials & Interfaces 2015 v.7 no.12 pp. 6792-6802
X-radiation, adsorption, carbon dioxide, composite polymers, nitrogen, nuclear magnetic resonance spectroscopy, polyethyleneimine, porosity, porous media, silica, sorption isotherms, spinning, stable isotopes, surface area
CO₂ adsorption was investigated on amine-functionalized mesoporous silica (SBA-15) and periodic mesoporous organosilica (PMO) samples. Hexagonally (p6mm) ordered mesoporous SBA-15 and benzene-PMO (BPMO) samples were prepared in the presence of Pluronic P123 block copolymer template under acidic conditions. Three kinds of amine-containing organosilanes and polyethylenimine were used to functionalize SBA-15 and BPMO. Small-angle X-ray scattering and nitrogen adsorption isotherms showed that these samples featured ordered mesostructure, high surface area, and narrow pore size distributions. Solid-state ¹³C- and ²⁹Si cross-polarization magic-angle spinning NMR spectra showed chemical linkage between amine-containing modifiers and the surface of mesoporous materials. The chemically linked amine-containing modifiers were found to be on both the inner and outer surfaces. N-[3-(trimethoxysilyl)propyl]ethylenediamine-modified BPMO (A2-BPMO) sample exhibited the highest CO₂ uptake (i.e., ∼3.03 mmol/g measured on a volumetric adsorption analyzer) and the fastest adsorption rate (i.e., ∼13 min to attain 90% of the maximum amount) among all the samples studied. Selectivity and reproducibility measurements for the A2-BPMO sample showed quite good performance in flowing N₂ gas at 40 mL/min and CO₂ gas of 60 mL/min at 25 °C.