A surfactant modified solid amine adsorbent to enhance CO2 adsorption performance

Abstract

Solid-amine adsorbents are promising CO2 post-combustion adsorption materials to mitigate global warming. As one of the most important evaluation criteria, the CO2 adsorption capacity of the adsorbent was determined by both kinetic and thermodynamic factors, while high temperature is good for mass transfer and low temperature is advantageous for equilibrium to move towards adsorption. In this study, surfactants were added into polyethylenimine (PEI) cryogel to enhance mass transfer and reduce the adsorption temperature, thereby promoting its adsorption capacity. With the addition of polyethylene glycol (PEG200), the CO2 adsorption capacity reached a maximum value of 6.48 mmol/g at 65 °C, and the amine efficiency reached a maximum value of 0.52 mol C/mol N at 45 °C. Further characterization revealed that the addition of PEG not only enhanced the mass transfer, but also changed the chemisorption mechanisms, which were very similar to the effects of water. Besides, PEG would form hydrogen bonds with the PEI polymer network and showed stable regeneration capacity, thereby exhibiting a greater application potential.