Epoxide-Functionalization of Grafted Tetraethylenepentamine on the Framework of an Acrylate Copolymer as a CO2 Sorbent with Long Cycle Stability

Adsorptive capture of CO2 using amine-based adsorbents is a promising strategy for reducing energy penalty, while the stability of solid amines remains the most critical challenge. In this work, we propose a novel methodology to significantly extend the stability of CO2 adsorbents. By copolymerizing water-in-oil emulsion containing multiple acrylates with rich epoxide groups, we synthesize porous beads with a hydrophobic and robust framework to ensure long-term thermal and hydrothermal stabilities. We then graft tetraethylenepentamine on the framework via ring-opening reaction between the epoxide and amine groups to resist amine leaching and oxidation. Finally, we convert most of the remaining primary amines and some secondary amines of the grafted tetraethylenepentamine to secondary and tertiary ones through epoxide-functionalization to prevent urea formation and sulfur poisoning. With a nitrogen content of 10.0 mmol·g–1, the adsorbent achieves 2.03 mmol·g–1 CO2 uptake at 60 °C and, which remains constant when exposed to air at 90 °C for 12 h. After 1000 adsorption/desorption cycles, its adsorption capacity drops by 9.8% in a simulated flue gas containing O2, SO2, and water steam, showing a long-term lifespan in a complex environment.