Adsorption separation of CO₂ from flue gas by hyperbranched solid-amine

Hyperbranched solid amine was prepared with KIT-6 type mesoporous silica, which was modified by tetraethylenepentamine (TEPA) using post-synthetic impregnation. The adsorption behavior of CO₂ on KIT-6(TEPA) was investigated using an adsorption column. The adsorption capacity of KIT-6(TEPA) for CO₂ increased with temperature at 303-343 K, but decreased as temperature increased at 343-353 K. The maximum adsorption capacity is 3.1 mmol g^-1 at 343 K. The mechanism of CO₂ adsorption on KIT-6(TEPA) is mainly chemical adsorption. The adsorption capacity is improved by moisture. It reaches 3.5 mmol·g^-1 in the presence of 12% water. The adsorption capacity is maintained after 20 cycles of adsorption and regeneration, indicating that the KIT-6(TEPA) is stable in a prolonged cyclic operation. Experimental breakthrough curves are fitted with a deactivation model, giving good agreement with experimental data.