Adsorption of CO2 on Amine-Functionalized Y-Type Zeolites

Abstract

Commercially available Y-type zeolite with a Si/Al molar ratio of 60 (abbreviated as Y60) was modified by tetraethylenepentamine (TEPA) to study their characterizations and adsorption/desorption properties of CO 2 from gas streams. The surface nature of Y60 was changed after TEPA modification, which causes a significant enhancement in CO 2 adsorption capacity. The CO 2 adsorption capacity of Y60(TEPA) increased with the temperature at 30−60 °C but decreased with the temperature at 60−70 °C. The mechanism of CO 2 adsorption on Y60 is entirely a physical interaction but becomes mainly attributable to a chemical interaction after TEPA modification. The CO 2 adsorption capacity of Y60(TEPA) was influenced by the presence of water vapor and reached as high as 4.27 mmol of CO 2 /g of sorbent at a water vapor of 7%. The cyclic CO 2 adsorption showed that the adsorbed CO 2 could be desorbed from the surface of Y60(TEPA) at 75 °C for 4 h. The adsorption capacities and the physicochemical properties of Y60(TEPA) were preserved after 20 cycles of adsorption and regeneration, suggesting that the Y60(TEPA) can be stably employed in the prolonged cyclic operation and that they are possibly cost-effective sorbents for CO 2 capture from flue gas.