CO₂ capture using particulate silica aerogel immobilized with tetraethylenepentamine

A high capacity CO₂ sorbent was developed using high porosity hydrophilic and hydrophobic silica aerogel impregnated with tetraethylenepentamine (TEPA). Aerogel sorbents were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, and nitrogen adsorption porosimetry for confirming the TEPA loadings and examining the residual porosity after modification. The aerogel sorbents appear to shrink during the drying step of amine impregnation while the surface chemistry of the support is altering the TEPA distribution within the pores. The adsorption performance was tested under pure and low CO₂ partial pressure conditions at 75 C where the hydrophilic aerogel sorbents outperformed the hydrophobic sorbents. The 80 wt.% TEPA loaded hydrophilic sorbent achieved the largest capacity of 6.1 mmol/g in pure CO₂ while also attaining 3.5 mmol/g under a dry 10% CO₂/Ar stream. The sorbent also showed excellent cyclic stability having a working CO₂ sorption capacity of 5.1 mmol/g over 10 cycles.