Carbon capture by DEA-infused hydrogels

Abstract

Escalating global temperatures have spurred the development of various CO2 sorbents. Liquid amines are the most widely employed sorbent but they exhibit multiples drawbacks including low absorption capacity, high regeneration energy and degradation of the amine. This work presents the performance of an entirely new CO2 absorbent that is prepared by simply adding commercial or synthesized hydrogels into a solution of a standard liquid amine, diethanolamine (DEA) solution with a low concentration (5.0 wt. %, 10.0 wt. % and 20.0 wt. %) to generate DEA-infused hydrogels. This new material can rapidly capture CO2 even with relatively low amounts of DEA Higher overall uptake has been achieved compared to the commonly used DEA solutions. Moreover, hydrogels with various crosslinking degrees were prepared and employed for preparing the DEA infused hydrogels. It was found that the overall CO2 absorption was largely independent of the crosslinking degree, but the absorption kinetics generally improved with a higher crosslinking degree. In addition, breakthrough experiments demonstrate the outstanding performance of this proposed material for CO2 removal from flue gas. The absorption capacity of the DEA-infused hydrogels is well maintained after multiple regeneration cycles especially with the addition of polyethylenimine (PEI) so the hydrogels can easily be recovered and reused. This new material shows promise as a new CO2 absorbent in the CO2 capture industry.