A Novel TEPA-Load or PEI-Load Beta/KIT-6 Composite and their Application to CO2 Adsorption

Abstract

An amine-modified Beta/KIT-6 (BK) micro/mesoporous composite for CO2 capture was synthesized using nonionic tri-block copolymer pluronic (P123) as a template, tetraethyl orthosilicate (TEOS) as a silicon source and Beta zeolite as part of silicon aluminum source by a two-step hydrothermal crystallization method. BK was modified by Tetraethylenepentamine (TEPA) or polyethyleneimine (PEI) to obtain solid amine adsorbent. The structure, uniformity and physical properties of the sample were characterized by FTIR, nitrogen adsorption/desorption and elemental analysis methods and CO2 adsorption/desorption behavior of adsorbents and regeneration performance were investigated by thermal gravimetric analysis (TGA). Experimental results showed that with the increase of amine loading the CO2 adsorption capacity of samples increased first and then decreased at [Formula: see text]C, TEPA-loaded BK and PEI-loaded BK both presented the largest saturated CO2 adsorption capacity when the amine loading reached 60%, and the maximum values were 4.21[Formula: see text]mmol[Formula: see text]g[Formula: see text] and 2.72[Formula: see text]mmol[Formula: see text]g[Formula: see text], respectively. BK-TEPA-60 and BK-PEI-60 reached the maximum adsorption capacity at [Formula: see text]C and [Formula: see text]C. The adsorption kinetics analysis showed that the adsorption process of amine-modified BK was dominated by both physical and chemical adsorption. After five cycles of adsorption/desorption, BK-PEI-60 kept better stability with the equilibrium adsorption capacity of exhibited just 2.9% attrition, whereas a 9.2% decrease was obtained for BK-TEPA-60. Compared with other amine-modified solid materials, the materials we designed show good CO2 adsorption performance, indicating that they are promising efficient adsorbents for CO2 capture.