CO₂ Sorption Kinetics of Scaled-Up Polyethylenimine-Functionalized Mesoporous Silica Sorbent

Abstract

Two CO2 solid sorbents based on polyethylenimine, PEI (M(n) ∼ 423 and 10K), impregnated into mesoporous silica (MPS) foam prepared in kilogram quantities via a scale-up process were synthesized and systematically characterized by a range of analytical and surface techniques. The mesoporous silica sorbent impregnated with lower molecular weight PEI, PEI-423/MPS, showed higher capacity toward CO2 sorption than the sorbent functionalized with the higher molecular weight PEI (PEI-10K/MPS). On the other hand, PEI-10K/MPS exhibited higher thermal stability than PEI-423/MPS. The kinetics of CO2 adsorption on both PEI/MPS fitted well with a double-exponential model. According to this model CO2 adsorption can be divided into two steps: the first is fast and is attributed to CO2 adsorption on the sorbent surface; the second is slower and can be related to the diffusion of CO2 within and between the mesoporous particles. In contrast, the desorption process obeyed first-order kinetics with activation energies of 64.3 and 140.7 kJ mol(-1) for PEI-423/MPS and PEI-10K/MPS, respectively. These studies suggest that the selection of amine is critical as it affects not only sorbent capacity and stability but also the energy penalty associated with sorbent regeneration.

Detection of Volatile Organic Compounds Using Microfabricated Resonator Array Functionalized with Supramolecular Monolayers

“…Mono-exponential equations (3a) and (3b) were applied to fit the real-time adsorption and desorption data. [47][48][49] …”

Kinetics of CO2 Adsorption/Desorption of Polyethyleneimine‐Mesoporous Silica

“…Among the adsorption techniques, capturing CO 2 on immobilized amine sorbents has been considered as one of the most promising approaches . So far, amines immobilized on mesoporous silica (MPS) have been shown to have the highest CO 2 adsorptivity, high desorption rate, negligible corrosion problems, and low energy consumption during regeneration , . To date, a series of amine‐supported mesoporous silicas have been prepared and investigated , , , , , .…”

Thermodynamics of CO2 Adsorption on Polyethyleneimine Mesoporous Silica and Activated Carbon

“…The most widely inorganic mesoporous support used till now is mesoporous silica [9][10][11][12][13][14][15]. Among the adsorption techniques, capturing CO 2 on amine immobilized on solid sorbents has been considered as a great promising approach [16][17][18][19]. So far, amines immobilized on mesoporous silica (MPS) have shown to have the highest CO 2 adsorptivity, high desorption rate, negligent corrosion problems, and low consumption of energy during regeneration [18,19].…”

“…Among the adsorption techniques, capturing CO 2 on amine immobilized on solid sorbents has been considered as a great promising approach [16][17][18][19]. So far, amines immobilized on mesoporous silica (MPS) have shown to have the highest CO 2 adsorptivity, high desorption rate, negligent corrosion problems, and low consumption of energy during regeneration [18,19]. Several amines supported mesoporous silica have been synthesized and studied [5,[9][10][11]15,18,20].…”

“…So far, amines immobilized on mesoporous silica (MPS) have shown to have the highest CO 2 adsorptivity, high desorption rate, negligent corrosion problems, and low consumption of energy during regeneration [18,19]. Several amines supported mesoporous silica have been synthesized and studied [5,[9][10][11]15,18,20]. Furthermore, when high molecular weight polyethyleneimine (PEI) is employed the volatilization and/or decomposition are expected to be minimal because of the relatively high melting temperature of such a high molecular weight material.…”