CO2 Capture Behaviors of Amine-Modified Resorcinol-Based Carbon Aerogels Adsorbents

ABSTRACT

Activated carbon aerogel (CA)-based amine-loaded adsorbent has been successfully developed for CO₂ capture. The adsorbents were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), N₂ adsorption/desorption and thermogravimetric analysis (TGA). The CO₂ adsorption performance was tested by the fixed bed system at 5% CO₂ concentration. The effects of the mass ratio of KOH to CA, type of amine, amine loadings, addition of polyethylene glycol (PEG) or surfactants and adsorption temperature on the CO₂ capture performance of amine-loaded activated CA as well as the regeneration capability were examined. The results show that the adsorbents effectively remove 5% CO₂ from gas mixtures. The optimum adsorption temperature and amine loadings of polyethyleneimine (PEI)-loaded activated CA are 75°C and 55 wt.% respectively at the activation mass ratio KOH to CA of 1. Under these optimum conditions, the PEI-loaded activated CA reaches the highest adsorption capacity of 2.06 mmol g^–1 adsorbent. Addition of PEG facilitates the CO₂ adsorption. Suyadal’s and Yasyerli’s deactivation models both fit the experimental breakthrough curves of tetraethylenepentamine (TEPA)-loaded activated CA better than that of PEI-loaded activated CA. The adsorption kinetics nonlinear fitting results show that the adsorption process follows Bangham model.