Poly(ethylenimine)‐Functionalized Monolithic Alumina Honeycomb Adsorbents for CO₂ Capture from Air

Abstract

The development of practical and effective gas-solid contactors is an important area in the development of CO2 capture technologies. Target CO2 capture applications, such as postcombustion carbon capture and sequestration (CCS) from power plant flue gases or CO2 extraction directly from ambient air (DAC), require high flow rates of gas to be processed at low cost. Extruded monolithic honeycomb structures, such as those employed in the catalytic converters of automobiles, have excellent potential as structured contactors for CO2 adsorption applications because of the low pressure drop imposed on fluid moving through the straight channels of such structures. Here, we report the impregnation of poly(ethylenimine) (PEI), an effective aminopolymer reported commonly for CO2 separation, into extruded monolithic alumina to form structured CO2 sorbents. These structured sorbents are first prepared on a small scale, characterized thoroughly, and compared with powder sorbents with a similar composition. Despite consistent differences observed in the filling of mesopores with PEI between the monolithic and powder sorbents, their performance in CO2 adsorption is similar across a range of PEI contents. A larger monolithic cylinder (1 inch diameter, 4 inch length) is evaluated under conditions closer to those that might be used in large-scale applications and shows a similar performance to the smaller monoliths and powders tested initially. This larger structure is evaluated over five cycles of CO2 adsorption and steam desorption and demonstrates a volumetric capacity of 350 molCO2 m-3monolith and an equilibration time of 350 min under a 0.4 m s(-1) linear flow velocity through the monolith channels using 400 ppm CO2 in N2 as the adsorption gas at 30 °C. This volumetric capacity surpasses that of a similar technology considered previously, which suggested that CO2 could be removed from air at an operating cost as low as $100 per ton.

Parametrical Study on CO2 Capture from Ambient Air Using Hydrated K2CO3 Supported on an Activated Carbon Honeycomb

“…This indicates the influence of the CO 2 partial pressure on the total salt conversion. Furthermore, the capture capacity of our adsorbent was lower than the 0.7 mmol CO 2 /g ads reported by Sakwa-Novak et al 29 for their amine-based adsorbent. However, the difference in the active compound loading is also significant: 30.5 wt % for their poly(ethylenimine) and 5.58 wt % for our current K 2 CO 3 -based adsorbent.…”

Macroporous Silica with Thick Framework for Steam‐Stable and High‐Performance Poly(ethyleneimine)/Silica CO2 Adsorbent

“…Considering the chemisorption nature of CO 2 on amine‐based materials, the adsorbents can be most efficiently regenerated by temperature swing adsorption (TSA) . To design a practical TSA process that enables the separation of high‐purity CO 2 for sequestration/utilization, the saturated adsorbents should be regenerated under a CO 2 ‐rich atmosphere using primarily a thermal driving force (the separated CO 2 can be recycled as a purge gas) .…”

“…[15,32,33] Considering the chemisorption nature of CO 2 on aminebased materials, the adsorbentsc an be most efficiently regenerated by temperature swing adsorption (TSA). [22,31,42,46] To design ap ractical TSA process that enables the separation of high-purity CO 2 fors equestration/utilization, the saturated adsorbentss hould be regenerated under aC O 2 -rich atmosphere using primarily at hermald riving force (the separated CO 2 can be recycled as ap urge gas). [22,31] Unfortunately,arelatively high temperature (> 120 8C) mustb eu sed to desorb CO 2 under aCO 2 -rich atmosphere,inw hicht he significant deactivation of amines can occur through urea formation (i.e., dehydrative condensation between amines and CO 2 ).…”

Nano-Doped Monolithic Materials for Molecular Separation

“…The obtained limit of detection and quantification were 2.8 and 9.1 mg·L −1 , respectively. In addition, other reports have also been established in the use of alumina particles as monomeric units (raw materials) in the synthesis of monolithic adsorbents for the control of flue gases [120]. Contrary to the copolymerisation/polymerisation protocols described above, Li et al [121] modified the epoxide functional groups on the surface of poly(NIPAAm-co-GMA-co-EDMA) using an optimised amount of NaOH with homogeneously dispersed γ-Al 2 O 3 nanoparticles.…”