Synthesis of porous carbon beads with controllable pore structure for volatile organic compounds removal

Abstract

Spherical porous carbon materials (SPCMs) have attracted considerable interest due to the excellent mechanical performance and abundant pore structure. In this work, porous carbon beads (PCBs) of around 1.5mm were synthesized via phase inversion route followed by carbonization. Specially, porous polymeric beads (PPBs) were obtained by injecting of polyvinylidene fluoride (PVDF) polymer solution containing phenolic resins into coagulation bath. The porous structure of PPBs can be adjusted by simply altering the composition of coagulation bath, which further determined the final microstructure of PCBs. Mercury porosimeter, SEM and N2 adsorption-desorption isotherms characterization revealed that the resultant PCBs possess uniform spherical shape, abundant macrospore and high mesoporosity. The sample obtained under the moderate phase inversion condition, i.e. PCBs-2, possesses highest BET surface area (1166m2/g), mesoporous pore volume (0.249cm3/g) and pore size (2.87nm). To present the removal performance of PCBs for volatile organic compounds (VOCs), the adsorption behaviors under static and dynamic conditions were investigated. The static adsorption result indicated that PCBs-2 exhibits the largest adsorption capacities for benzene (1.467g/g), toluene (1.229g/g), n-hexane (0.600g/g) and acetone (0.770g/g). Dynamic adsorption on thermogravimetric analyzer reveled that PCBs-2 presents higher adsorption capacity and faster adsorption kinetics for benzene vapor. Breakthrough curves obtained from fixed bed on PCBs-2 and commercialized granular activated carbon further confirms the enhanced adsorption capacity was achieved on PCBs-2. After 6 adsorption-desorption cycles, the steady dynamic adsorption capacity can be reserved with negligible change. These results imply that PCBs-2 has great potential as a promising candidate for the abatement of VOCs.