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

•Nanogel particles are deposited onto carbon paper by a spray coating method.•CO2 adsorption-desorption experiments are performed in a milli-channel reactor.•The adsorbent exhibits fast CO2 adsorption rate and desorption rate.•The adsorbent presents good stability under wet conditions. 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.