Novel Pore-Expanded MCM-41 for CO₂ Capture: Synthesis and Characterization

Abstract

Recently, amine-functionalized mesoporous silica materials have attracted considerable attention as a promising chemical sorbent for postcombustion CO2 capture applications. However, the grafting of amines in the conventional MCM-41 support induces the subsequent reduction of surface area and pore volume of the sorbents, affecting the CO2 adsorption-desorption kinetics significantly. To mitigate this problem, expensive pore expansion agents have been used to increase the pore size as well as the pore volume. The present study provides an innovative approach to the development of novel pore-expanded MCM-41 without the application of any swelling agent. The average pore size (~30 nm) obtained in our work is remarkably higher than the values (9 to 10 nm) reported in the literature. On the basis of the fundamental understanding of micelle properties under different alkaline conditions, a mechanism for the pore expansion process is proposed. The outcome (1.2 mmol/g) of the preliminary CO2 adsorption studies carried out on the novel support material grafted with monoamine silane is very promising.

APTES grafted ordered mesoporous silica KIT-6 for CO2 adsorption

“…CCS is important to mitigate the global warming and its consequences by capture of CO 2 from large anthropogenic sources. Aqueous alkanolamines and chilled ammonia based absorption process [5,6], membrane separation process [7,8], novel cryogenic process [9], algal biomass process [10,11] and porous solid adsorption process [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] are most commonly used for CO 2 capture. Among these processes aqueous alkanolamine especially monoethanolamine (MEA) and diethanolamine (DEA) based absorption process is well known with significant commercial application for CO 2 capture.…”

“…Adsorption is an alternate and cost effective CO 2 capture process. In the recent years microporous activated carbon [22,23], metal organic frameworks (MOFs), zeolites [24,25] and amine functionalized silica and foams based adsorption processes [12][13][14][15][16][17][18][19][20][21][26][27][28][29] have shown strong potential for CO 2 capture.…”

“…MCM, SBA, MSU, silica foam and KIT-6 types have attracted great attention of a large community of researchers for catalysis [33,34], support [35], radiotherapy [36], drug delivery [37] and acidic gas separation [12][13][14][15][16][17][18][19][20][21] applications. It is well known that CO 2 adsorption capacity is directly proportional to accessible amine groups on the silica surface.…”

“…Loading of amino silane depends on the various conditions like surface area, pore volume, pore size, grafting temperature, physical properties of the material and grafting solvent. In most of the literature, mesoporous silica was grafted in anhydrous solution [12][13][14][15][16][17][18][19][20]. However, amine loading increases in presence of water.…”

Tailoring amine functionalized hybrid ceramics to control CO2 adsorption

“…The CO 2 sorption capacity usually decreases for amine grafted silica with temperature as observed for double-walled silica nanotubes and pore expanded mesoporous silica grafted with amines [51,60]. This is expected since only strong amine -CO 2 interactions will contribute to the sorption capacity at higher temperatures.…”