Mesoporous Silica Supported Polyethyleneimine for CO2 Capture from Air
6 Pages Posted: 3 Jun 2019
Date Written: October 21, 2018
The relative potential of mesoporous silica supported polyethyeleneimine type composites for CO2 direct from air capture (DAC) is investigated via isothermal static fixed volumetric CO2 sorption studies (30, 50 & 75 °C) and the thermogravimetry (20, 40, 50 & 60 °C) of their isothermal processing when fed a 400 ppm CO2 in Ar gas blend. The data derived from the static volumetric dosing technique was found useful for a basic assessment, however it was also found to substantially underestimate the likely capacity of the sorbents achievable during realistic CO2 DAC processing. The thermogravimetry results were found to be directly useful to assess the relative performance of different composites. Branched rather than linear PEI, and larger pore volume support materials, were found to be preferred for the application. The sorption kinetics and capacities of siliceous meso-cellular foam and branched polyethyleneimine composites were found to improve with temperature up to 50 °C. The composite incorporating the greatest amount of the PEI (80 % mesopore volume equivalents) exhibited 1.8 mmol/g CO2 capacity after 55 hours exposure to the gas feed at 50 °C.
Keywords: Capturing CO2 from the air or oceans, GHGT-14, CO2 capture, adsorption, polyethyleneimine, PEI, air.
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