High benzene adsorption capacity of micro-mesoporous carbon spheres prepared from XAD-4 resin beads with pores protected effectively by silica

The aim of this work was to prepare micro-mesoporous carbon spheres with high specific surface area and large volume of mesopores from porous styrene-co-divinylbenzene ion exchange resin Amberlite XAD-4 beads. Prior to the carbonization step, the mesoporous resin beads were protected by silica formed via impregnation of tetraethylorthosilicate followed by its hydrolysis and condensation. This was essential to obtain highly porous carbon spheres after silica removal that featured the specific surface area up to 1050 m² g⁻¹ and total pore volume up to 1.35 cm³ g⁻¹. Additional CO₂ activation resulted in micro-mesoporous carbon spheres and consequently boosted their adsorption capacity for benzene up to 21–24 mmol g⁻¹ at 20 °C and relative pressure close to unity. Moreover, carbon dioxide adsorption properties of the samples were studied, and the highest uptake of 4.5 mmol g⁻¹ at 0 °C and 1 bar pressure was obtained for the activated carbon. Our findings indicate that the activated carbon spheres exhibit a great potential for capture benzene and related volatile organic compounds.