Preparation of polystyrene-based activated carbon spheres and their adsorption of dibenzothiophene

Polystyrene-based activated carbon spheres (PACS) were prepared by steam activation and their adsorption performance to a sulfur-containing dibenzothiophene (DBT) was studied. The textural structure of PACS was characterized by scanning electron microscopy, N₂ adsorption, thermal gravimetric, and aqueous adsorption. Results showed that PACS with BET surface areas up to 979-1672 m²/g were obtained. The BET surface areas and pore volumes increased with activation time and steam flow rate except for the volume of narrow micropores (< 0.7 nm). The maximum adsorption capacity of PACS to DBT was 109.36 mg/g and the adsorption capacity was related to the volume of narrow micropores, independent of surface area and total pore volume. Irreversible adsorption existed between DBT and PACS. The larger the volume of the narrow micropores, the higher the desorption temperature and the larger the amount of sulfur retained after heating.