Insights into amine-resin matching strategy for CO2 capture: Adsorption performance tests and Mechanistic investigation

Abstract

The solid amine adsorbents are potential candidates as materials for post-combustion capture technologies. The type of organic amine and porous material are the key factors influencing the amine-based solid adsorbent performance. Furthermore, there has been relatively little research on the matching mechanism between organic amines and porous materials. This study aims to investigate the effect of the degree of matching between different organic amines and porous materials (X-5 resin) on the performance of CO2 capture. The results indicated that 30 wt% TETA was the highest matching degree with X-5 and had the maximum CO2 adsorption of 205.48 mg/g at 30 ℃. The matching degree between the four amines and the X-5 resin followed TETA > TEPA > PEHA > PEI. Since TETA has the simplest molecular structure, it can be conveniently dispersed in the X-5 pores, which not only significantly improves the utilization of active sites but also prevents the phenomena of agglomeration or sintering. Meanwhile, X-5-30TETA has the highest adsorption energy Eads (−85.22 kJ/mol) and the smallest spatial potential resistance, decreasing the mass transfer resistance effectively, thus further increasing the adsorption capacity. Furthermore, the adsorption kinetics results showed that the Avrami model can relatively accurately predict the experimental results of X-5-TPHI CO2 adsorption. Finally, the in situ DRIFTS indicated that the CO2 adsorption reaction over X-5-30TETA followed predominantly an amphipathic centipede mechanism. This work provides a new idea for the investigation of the matching mechanism between organic amines and porous materials.