A stable solid amine adsorbent with interconnected open-cell structure for rapid CO2 adsorption and CO2/CH4 separation

Abstract

A novel stable porous solid amine adsorbent with three-dimensional interpenetrating network structure was prepared by polymerization of divinylbenzene using high internal phase emulsion (HIPE) template method, and followed by further introducing polyethyleneimine (PEI) by impregnation-crosslinking method. Fixed bed dynamic adsorption experiment proved that under wet condition, the former exhibited not only a higher capacity of 6.22 mmol/g but also a better adsorption kinetics process with faster adsorption rate and longer lag in breakthrough point, which makes it potential to be used in gas separation. In CO2/CH4 separation experiment, PolyHIPE-PE30-4 showed a CO2/CH4 separation selectivity of 253 at 298 K and 1 bar, and meanwhile exhibited an extra-high operating capacity. The pure methane productivity of PolyHIPE-PE30-4 was 24.1 mmol/g from CO2/CH4 (80:20, v/v) mixed gas, 4.5 times to that of PE30-4 gel (5.36 mmol/g). Significantly, PolyHIPE-PE30-4 could maintain an excellent regeneration performance after at least 7 cycles, while PolyHIPE-P30 exhibited a remarkably decrease in adsorption capacity after only three adsorption-desorption process in wet condition, demonstrating the advantage of impregnation-crosslinking method for amine functionalization. The superior CO2 adsorption capacity and regeneration stability, combined with its superior adsorption kinetics property make it a broad prospect in the field of CO2/CH4 separation.