Melamine Mediated Synthesis Of Nitrogen-rich Polymer And Carbon Microspheres For CO₂Adsorption

Ultramicroporous nitrogen-rich polymer microspheres were synthesized by an extended stober method using resorcinol, formaldehyde, melamine as raw materials. The resulting nitrogen-rich carbon microspheres were obtained by a direct pyrolysis process or by a combined process of pre-oxidation and carbonization. The CO2adsortion performance of as-synthesized polymer and carbon microspheres were evulated. The major conculsions are summaried as follows:1) Monodisperse polymer microspheres were obtained in a wide condition. The optimum condition were as follows:the concentration was15wt%, reaction temperature was120℃, the reaction time was8h, RF precursor polymerization time was3h, M/F was1/3.2) The particle size and nitrogen content were determined by the ratio of M/R. The particle size of polymer were ranged from10μm to2μm as the ratio of M/F increasing from0to3, while nitrogen content increased from0to34wt%.3) The intrinsic ultraporosity of polymer were contributed by the RMF3D network. The pore volume increased as the increasing of M/F ratio. The highest surface area of polymer could reach395.1m2/g at the M/F ratio of1.5, while the pore volume was0.107cm3/g and pore size of0.35nm. The small pore size and basic nitrogen functionality incorporated into RMF should be the guarantees for high uptakes of CO2. The adsorption capacity of polymer for CO2could reach2.5mmol/g at273K and1.8mmol/g at298K. Furthermore, the polymer microspheres showed high selectivity to CO2from N2.4) The carbon microspheres were obtained by a direct pyrolysis process. The surface areas of carbon microspheres could reach826m2/g which were higher than polymer due to the release of small molecules. The nitrogen content reached12.5wt%. The CO2uptake of carbon micropsheres maintained4.5mmol/g at273K and3.3mmol/g at298K.5) The carbon microspheres were also obtained by the pre-oxidation and carbonization process.The nitrogen content could reach23.3wt%. The high nitrogen content were benefit to CO2uptake and other applications such as electrochemical performance.