Development of hybrid amine-functionalized MCM-41 sorbents for CO2 capture

In consideration of the increasing warming trends worldwide, the development of highly efficient CO2 adsorbents becomes of vital importance. In this paper, a novel hybrid 3-aminopropyltrimethoxysilane (APTS) and tetraethylenepentamine (TEPA) modified MCM-41 sorbent was synthesized by a two-step method. APTS was first grafted onto the MCM-41, and then TEPA was impregnated. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and N-2 adsorption-desorption techniques. CO2 adsorption-desorption experiments were performed in a self-assembled fixed bed reactor under ambient pressure. The effects of hybrid amine loadings, adsorption temperatures, and influent velocities on CO2 sorption were investigated. Among the composites synthesized, MCM-41 modified with 30 wt.% APTS and 40 wt.% TEPA (MCM-41-APTS30%-TEPA40%) showed maximum adsorption capacity of 3.50 mmol-CO2/g-sorbent. The MCM-41-APTS30%-TEPA40% sorbent exhibited well cyclic regenerability after ten adsorption-desorption cycles. Further, the adsorption kinetics of MCM-41 and MCM-41-APTS30%-TEPA40% were studied. CO2 adsorption was a two-stage process, and the Avrami model could fit well with the experimental data of MCM-41-APTS30%-TEPA40%. (C) 2014 Elsevier B.V. All rights reserved.