Silanol-rich platelet silica modified with branched amine for efficient CO2 capture

Abstract

In this work, we report a new route to improve the CO 2 adsorption performance of solid amine adsorbents. Platelet mesoporous silicas with abundant surface silanols were prepared by emulsion synthesis followed by simple solvent extraction. These silanol-rich silica particles were then functionalized with branched polyethyleneimine (BPEI) by grafting or impregnation to prepare CO 2 adsorbents. Silanol-rich silicas grafted with BPEI exhibited 70% higher amine density and 47% higher CO 2 adsorption capacity than its calcined counterpart. The adsorbent achieved a maximum CO 2 adsorption efficiency up to 13.82 mmol CO 2 / g-BPEI. Adsorbed species found in the infrared spectra suggested that silanols may contribute to the enhanced CO 2 adsorption efficiency on grafted amines. Silanol-rich silica functionalized with BPEI retained more porosity than its calcined counterparts, which may account for its superior CO 2 adsorption capacity. Silanol-rich silica impregnated with amines achieved the highest CO 2 adsorption efficiency ever reported (5.65 mmol/ g, 526.7 mg/ g-BPEI). Adsorption kinetic modeling confirmed that silanol-rich adsorbent provides better CO 2 diffusion pathways. These potential benefits of silanol-amine interaction, coupled with platelet mesoporous structure and branched polyamine chains, opens a new pathway to high-performance adsorbents for CO 2 capture.

High iodine adsorption by polyethyleneimine impregnated nanosilica sorbents

“…Overall, our results seem to show that iodine adsorption takes place mostly in the mesopores for low-medium PEI contents and outside of the porosity or at the pore mouth when the pores are getting totally filled with PEI. Consistently with our results, literature studies also indicate optimum organic loadings in the range 30-50 wt% in the case of CO2 adsorption by PEI-silica materials [24,[32][33][34]. At higher PEI contents, the diffusion of CO2 was found to be severely hindered by the high concentration of PEI molecules in the porosity.…”

The dynamic CO2 adsorption of polyethylene polyamine-loaded MCM-41 before and after methoxypolyethylene glycol codispersion

“…[1][2][3] Solid amine adsorption technology, with weak corrosivity, highly efficient adsorption performance and low regeneration energy consumption, is recognized as an effective method. [4][5][6][7] So far the study of amine-loaded solid sorbents mainly focuses on immobilizing amines onto the inner surface of porous supporting materials, such as metal-organic frameworks (MOFs), [8][9][10][11][12][13] mesoporous molecular sieves, 14-22 silicas [23][24][25][26][27][28][29][30][31] and so on. [32][33][34][35][36][37][38][39][40] Chen et al incorporated polyethyleneimine (PEI) into mesoporous zeolite 13X prepared by pore-expanding original micropores; due to PEI-dispersion in mesopores, the CO 2 adsorption capacity for PEI-modied 13X reached 80 mg g À1 at 100 C under a pure CO 2 atmosphere.…”

Impacts of nano-scale pore structure and organic amine assembly in porous silica on the kinetics of CO2 adsorptive separation

“…However, most studies focused on tailoring of the pore structure are aiming to mainly modifying the pore size and pore volume of cylindrical pores: Therefore, the design of pore shape to further modify the loading of organic amines in pores, which is also important for releasing free pore space along with the modifying of pore properties, should also be considered and remains to be explored. Moreover, a few studies reported that the changes of amine assembly can also significantly influence the sorption performance [26,27]; however, the design and fabrication of sorbents with arranged amine assembly are still challenging. More importantly, the influence of nano pore structure and amine assembly on sorption and desorption kinetics, which is of great importance for the future design of sorbents, is also unclear.…”