Mesoporous Chitosan–SiO2 Nanoparticles: Synthesis, Characterization, and CO2 Adsorption Capacity

Mesoporous chitosan–SiO2 nanoparticles (NPs) were successfully synthesized. The prepared nanoparticles were characterized using TEM, FTIR, XRD, TGA, EDX, and (CHN) elemental analysis. From TEM micrograph, chitosan–SiO2 NPs were sphere-like, pretty uniformly distributed with coarse surface. The average size of chitosan–SiO2 NPs was determined as 211 nm with DLS, which was confirmed by TEM. The mesoporous structure of chitosan–SiO2 NPs was characterized with N2 adsorption/desorption measurements. BET surface area was 621 m2 g–1 and the total pore volume was 0.71 m3 g–1. CO2 adsorption was evaluated by a volumetric method. Chitosan–SiO2 NPs showed a maximum CO2 adsorption capacity of 4.39 mmol g–1 at 25 °C and a high selective separation capacity for CO2 over N2 (SCO2/N2 = 15.46). The influence of amines on carbon dioxide adsorption was discussed. Stable CO2 adsorption/desorption was confirmed after six cycles of experiments. Therefore, chitosan–SiO2 NPs exhibit great potential for CO2 capture.