Development of an amine-impregnated polymer aerogel for CO2 capture

Abstract

The synthesis and characterization of amine-impregnated polymer aerogels for CO2 capture represents a groundbreaking advancement in combating the urgent challenges of carbon dioxide (CO2) emissions and climate change mitigation. The traditional way of synthesizing aerogels for CO2 capture is to use a one-step gelation process without functionalizing the aerogel, which, to some extent, has low CO2 capture capacity and kinetics. This study finds a method of synthesizing the functionalized aerogel, which has high CO2 adsorption capacity, faster kinetic, and is more stable. The polymer aerogel was developed using an oil-water emulsion polymerization method, followed by freeze-drying. It was impregnated with a mono-ethanolamine (MEA) solution to enhance CO2 adsorption. The performance of the amine-impregnated poly (AAm-co-AAc) aerogels was tested in a continuous adsorption column filled with aerogel. The adsorption results showed the amine-impregnated aerogels having an amine equilibrium uptake value of 40% had significantly improved CO2 capture capacity up to 2.34 mmole g−1 at 1 bar pressure, 25 °C reaction temperature, and 10 ml/min flow rate. The polymeric aerogel has a very fast adsorption rate, as it can capture 90% of its maximum capacity within just 10 minutes. Then the kinetic data of the CO2 adsorption was modelled and found to best fit on both pseudo-1st and 2nd-order kinetic models, proposing that the adsorption mechanism on aerogel was controlled by surface diffusion and chemisorption. Furthermore, the isotherm data were evaluated and observed to be best represented by the Langmuir isotherm model, suggesting monolayer formation on the aerogel. After five adsorption-desorption cycles, the amine impregnated poly (AAm-co-AAc) aerogel was able to preserve the initial capacity without a significant decrease. These findings underscore the immense ability of amine-impregnated poly (AAm-co-AAc) aerogels as highly efficient adsorbents for CO2 capture, thus offering a speedy adsorption process and showing stable regeneration capacity, thereby exhibiting greater industrial application potential.