Epoxide-functionalization of polyethyleneimine for synthesis of stable carbon dioxide adsorbent in temperature swing adsorption

Abstract

Amine-containing adsorbents have been extensively investigated for post-combustion carbon dioxide capture due to their ability to chemisorb low-concentration carbon dioxide from a wet flue gas. However, earlier studies have focused primarily on the carbon dioxide uptake of adsorbents, and have not demonstrated effective adsorbent regeneration and long-term stability under such conditions. Here, we report the versatile and scalable synthesis of a functionalized-polyethyleneimine (PEI)/silica adsorbent which simultaneously exhibits a large working capacity (2.2 mmol g−1) and long-term stability in a practical temperature swing adsorption process (regeneration under 100% carbon dioxide at 120 °C), enabling the separation of concentrated carbon dioxide. We demonstrate that the functionalization of PEI with 1,2-epoxybutane reduces the heat of adsorption and facilitates carbon dioxide desorption (>99%) during regeneration compared with unmodified PEI (76%). Moreover, the functionalization significantly improves long-term adsorbent stability over repeated temperature swing adsorption cycles due to the suppression of urea formation and oxidative amine degradation.

Design of hyperporous graphene networks and their application in solid-amine based carbon capture systems

“…S35 †). 4,5,7,8,10,11,[13][14][15][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Here, it is worth noting that the pore volume of our exfGO samples is much higher than those reported in the literature for amine impregnation.…”

“…5b). 4,7,8,[13][14][15][21][22][23][24][25][26][27][28]32,33 Here it is worth noting that the capacity loss of z21% in our TEPA@exfGO sample is arguably smaller than the z40% capacity loss from TEPA@mesoporous silica capsules, under similar synthetic and experimental conditions.…”

“…Due to their ultrahigh pore volume, exfGO-D samples can accept a record high TETA loading of z10 g g À1 of sample, without any sign of surface wetting (Table S6 †). 4,7,8,[13][14][15][21][22][23][24][25][26][27][28] Indeed, SEM micrographs still show void spaces for a TETA loading as high as 7.0 g g À1 in the exfGO-D sample (Fig. S26 †).…”

“…4c, S30, Tables S6 and S8 †). 4,5,7,8,10,11,[13][14][15][20][21][22][23][24][25][26][27][28][29][30][31][32][33] These uptake capacities are further conrmed under a simulated ue-gas stream of z100 ml min À1 , consisting of only 15% of CO 2 in N 2 , bubbled through water. A CO 2 capture of 35-40 wt% from the ue-gas is attained at 75 C ( Fig.…”

Carbon‐based adsorbents for post‐combustion capture: a review

“…The basic chemistry of CO 2 adsorption on immobilized amines is very similar to amine scrubbing (typical chemisorption), which is responsible for its high CO 2 uptake in PCC conditions. Deactivation is a concern for amine‐based adsorbents, which can be alleviated by controlled regeneration or modification of the amines Metal‐organic frameworks (MOFs).…”