Composite Molecular Sieve ZSM-5/MCM-48-Based Impregnation Modification for Efficient Adsorption of CO2

Micro/mesoporous materials are low-cost functional materials with the potential for CO2 adsorption. Modifying micro/mesoporous materials is significant for enhancing CO2 adsorption and their high-value utilization. Herein, the micro/mesoporous material of composite molecular sieve ZSM-5/MCM-48 (ZM) was synthesized by a two-step crystallization method using cetyltrimethylammonium bromide as a template, tetraethyl orthosilicate as a silicon source and ZSM-5 seed as part of silicon aluminum source. Tetraethylenepentamine (TEPA) and polyethyleneimine (PEI) were used as impregnation modifiers to modify ZM with amine groups. The results showed that with the increase of amine loadings, both ZM-T60 (Impregnated with TEPA) and ZM-P60 (Impregnated with PEI) functionalized adsorbents exhibited the best adsorption capacities of 4.97mmol & sdot;g(-1) and 3.28mmol & sdot;g(-1) at 60, respectively, when the loading of ZM sample was 60%. The adsorption kinetic analysis showed that the adsorption of CO2 by ZM-T60 and ZM-P60 was a chemisorption-dominated process accompanied by physical adsorption. After 10 adsorption/desorption cycles, the CO2 adsorption capacity of ZM-T60 and ZM-P60 decreased by 8.7% and 2.6%, respectively. This work demonstrates that impregnation modification of the composite molecular sieve to achieve efficient CO2 adsorption has practical application significance.