Pore-expanded MCM-41 for CO2 adsorption: Experimental and isotherm modeling studies

Abstract

In the current scenario, pore-expanded mesoporous silica materials are explored as promising supports for the art of amine tethering. Recently, our research group fabricated a pore-expanded MCM-41 (PE-MCM-41) through a cost-effective approach for carbon capture application. In the current work, adsorption isotherm measurements of pure CO2 on PE-MCM-41 are carried out at four different temperatures (30, 45, 60 and 75°C) under the pressure regime of 0–25bar using a Rubotherm magnetic suspension balance. Diffuse reflectance infrared spectroscopy (DRIFTS) analysis is carried out in order to get an insight into various surface functionalities that can exist on PE-MCM-41. The experimental CO2 uptake data are fitted to Langmuir, Sips, Toth and Langmuir multi-site models. To figure out the potential surface groups responsible for CO2 adsorption, patch-wise topography hypothesis is developed. The Langmuir multi-site isotherm model together with heat of adsorption calculations enlightens that CO2 adsorption on PE-MCM-41 occurs via both dispersion forces and hydrogen bonding.