Vacuum-assisted synthesis of spherical activated carbon using coal tar pitch with low softening point by copolymerization

Abstract Coal tar pitch with a softening point (SP) of 78 °C is mixed with divinylbenzene (DVB) and then spheroidized by suspension method in dimethyl silicone oil for 1 h. During the spheroidization process, the mixtures of pitch and DVB are copolymerized due to vinyl in DVB. After vacuum-assisted heat treatment, the copolymer spheres can be stabilized completely and then carbonized directly at high temperature under Ar atmosphere without melting and deformation. After activation using steam at 850 °C for 1.5 h, spherical activated carbon (SAC) with smooth surface and specific surface area SBET = 520 m2 g−1 can be prepared. Further studies show that mesopore volume of the SAC is 0.29 cm3 g−1, which accounts for 72.5% of the total pore volume. The good spherical morphology, smooth surface and rich pores (micropores and mesopores) can be attributed to appropriate copolymerization and vacuum-assisted treatment.