Polyamine nanogel particles spray-coated on carbon paper for efficient CO₂ capture in a milli-channel reactor

In this work, we report a proof-of-concept study on CO₂ adsorbents synthesized by a thermally initiated free-radical copolymerization and then coated onto carbon paper and poly tetra fluoroethylene via a spray coating approach. A milli-channel reactor was employed to support the obtained materials for efficient CO₂ capture with wet conditions, short cooling and heating cycles (303–348 K). CO₂ uptake and release performance of the materials were measured and compared with that of the polyamine-based materials prepared by other methods. CO₂ adsorption and desorption kinetics can be greatly enhanced when using the spray coating approach, especially for carbon paper as supporter. The CO₂ adsorption capacity of the spray-coated carbon paper reaches 80% of its maximum value in only 4.37 ± 0.7 min. Moreover, its adsorption rate (114.6 mg/(g∙min) at 303 K) and desorption rate (239.9 mg/(g∙min) at 348 K) were 81.2% and 81.5% higher than those of the polyamine-impregnated carbon paper, respectively (12% CO₂ at atmospheric pressure). Their largest increases of 71% and 67% were achieved by adjusting the concentration of polyamine nanogel particles deposited on the carbon paper surface. The prepared material also presents stable recyclability over 10 wet adsorption–desorption cycles and the aging experiments. The results obtained in this study indicate that the synthesized materials can serve as promising energy-efficient solid adsorbents for CO₂ capture.