Enhancement of CO2 Adsorption/Desorption Properties of Solid Sorbents Using Tetraethylenepentamine/Diethanolamine Blends

摘要

Mesocellular silica foam was impregnated with tetraethylenepentamine (TEPA), diethanolamine (DEA), and their mixtures and examined as sorbents for CO_(2) capture. The sorbents were characterized by N_(2) physisorption, elemental analysis, and Fourier transform infrared spectroscopy. The effects of amine blending on the CO_(2) uptake, working capacity, and heat of adsorption were investigated and discussed. The experimental results showed that the heat of adsorption decreased with increasing DEA-to-TEPA ratios, but the CO_(2) uptake improved by the blending of TEPA and DEA. Furthermore, the DEA/TEPA blend considerably improved the regeneration properties of the sorbents. Mesocellular silica foam loaded with a mixture of 40 wt % TEPA and 30 wt % DEA exhibited a CO_(2) adsorption uptake of 5.91 mmol/g at 50 °C and 100 kPa with a heat of adsorption of 80 kJ/mol. Additionally, these sorbents demonstrated high cyclic stability and high selectivity toward CO_(2)/N_(2) separation. In situ infrared spectroscopy investigations revealed that CO_(2) adsorption occurred predominantly through the formation of carbamate species for both TEPA and DEA.