Surface molecular design of organic–inorganic mesoporous hybrid materials for CO2 capture

Recent advances in direct air capture by adsorption

“…So far, various aminosilanes including aminomethyl- (C1), 273 2-aminoethyl- (C2), 273 3-aminopropyl- (APS), 120,125,126,134,273–287 4-aminobutyl- (C4), 273 5-aminoamyl- (C5), 273 N -methylaminopropyl- (MAPS), 274 N -butylaminopropyl- (NBAPS), 288,289 3-amino-3-methylbutyl- (AMBS), 127 tert -butylaminopropyl- (TBAPS), 127 N -cyclohexylaminopropyl- (CHAPS), 127 N -phenylaminopropyl- (PHAPS), 288 N , N -dimethylaminopropyl- (DMAPS), 274 3-(2-aminoethylamino)propyl- (DI), 134,287,290–292 3-(2-aminopropylamino)propylsilane ( l -propyl), 134 N , N ′-bis(3-trimethoxysilpropyl)urea (UREA), 275 3-[2-(2-aminoethylamino)ethylamino]propyl- (TRI), 114,120,128,129,287,293–295 3-(2-aminoethylamino)methylsilane (CH 2 DETA), 296 bis(2-aminoethyl)amine (B-ethyl), 134,296 bis(2-aminopropyl)amine (B-propyl), 134 and TREN, 121,134,260 have been tested for their ability to capture CO 2 from ultradilute concentrations of gas mixtures. In general, primary amines have higher amine efficiencies than secondary and tertiary amines due to the entropy effect, 274,288 which has led to the widespread use of APS for capturing CO 2 under ultradilute conditions.…”

“…A later study explored three nonpolar, two dipolar-aprotic, and three polar-protic solvents for amine grafting, confirming the high correlation between the solvent polarity and hybrid properties. 285 More specifically, the CO 2 capacities and efficiency of grafted amines depend on the interactions between the support matrix and solvents (Fig. 11b).…”

“…The efficient assembly of amine-grafted adsorbents relies on supports with a high specific surface area, adjustable pore structure, and rich surface hydroxyl groups. Most amine-grafted CO 2 adsorbents use ordered mesoporous silicas as supports, such as MCM-41, 124,297 pore-expanded MCM-41, 124,275,277,293 MCM-48, 352 SBA-15, 122,123,125,127,128,134,145,265,273,276,281,285,287,292,300 KIT-6, 298,299 and MCF. 274 Understanding the effect of the pore structure of siliceous supports on amine grafting and CO 2 adsorptive performance is essential.…”

Preparation of polybenzimidazole‐based mixed matrix membranes containingmodified‐COK‐12 mesoporous silica and evaluation of the mixed‐gas separation performance

“…It is worth mentioning that several porous fillers such as silica, zeolite, MOF, carbon nanostructures, and so on, have been explored for improving both CO 2 permeability and selectivity in MMMs 28 . Among these fillers, the ordered mesoporous silicas (OMS) are considered the most relevant, versatile, easy‐to‐synthesize, and useful filler for CO 2 separation and capture processes 29 …”

“…28 Among these fillers, the ordered mesoporous silicas (OMS) are considered the most relevant, versatile, easy-to-synthesize, and useful filler for CO 2 separation and capture processes. 29 OMS are silicon dioxide-based materials that exhibit 2D and 3Dporous structures with specific ordered pore arrangement (hexagonal, cubic, lamellar, etc.) and pore sizes ranged 2-50 nm.…”