Epoxide-functionalization of polyethyleneimine for designing extra-stable carbon dioxide adsorbent via temperature swing adsorption

Abstract

Amine-containing porous materials have been extensively investigated as an adsorbent for post-combustion $CO_2$ capture due to their effective capturing ability of low-concentration $CO_2$ (ca. 15%) from a wet flue gas. However, earlier studies have focused primarily on the carbon dioxide uptake of adsorbents, and have not demonstrated effective adsorbent regeneration and long-term stability under such conditions. Here we report the scalable synthesis of a functionalized-polyethyleneimine/silica adsorbent which simultaneously exhibits a large $CO_2$ working capacity as well as long-term stability in a practical temperature swing adsorption process (regeneration under 100% $CO_2% at %120 ^\circ C$). We demonstrate that the functionalization of polyethyleneimine (PEI) with 1,2-epoxybutane reduces the heat of adsorption and enhances $CO_2$ desorption properties during regeneration. Moreover, the functionalization significantly improves long-term adsorbent stability over repeated TSA cycles due to the suppression of urea formation and oxidative amine degradation.