Amine-impregnated carbon aerogels with ultra-high pore volume synthesized by pH adjusting for efficient CO2 Capture

Carbon aerogels with ultra-high pore volume and meso/macro pores were successfully synthesized by using silica hard templating combined sol–gel method by controlling the pH value of the initial reaction solution. High loadings (65–80 wt%) of TEPA (tetraethylenepentamine) and PEI (polyethyleneimine) were impregnated into CA with a high pore volume of 5.7 cm3/g for CO2 adsorption, respectively. The effects of amine loading, CO2 concentration, adsorption temperature, and moisture on the CO2 adsorption performance of the amine-loaded CA sorbents were comparatively investigated. The results showed that the CA with ultra-high pore volume enabled excellent CO2 adsorption capacity and fast kinetics (5.93 mmol/g and 4.70 mmol/g within 2.5 min for the case of TEPA and PEI respectively at 75 °C under 10% dry CO2). The sorbents exhibited good recycle-ability both in dry and humid conditions. Under humid conditions, the diffusion resistance of the sorbents at the initial stage of CO2 adsorption was observed. This study suggests that CA with large pore size could be utilized as promising amine sorbent for post-combustion CO2 capture.