Preparation and performance evaluation of resin-derived carbon spheres for desulfurization of fuels

A polystyrene-based ion-exchange resin was employed as the precursor for preparation of resin-derived carbon spheres (RCSs) through KOH activation with various impregnation ratios. Pore structure, yield and hardness, surface functional groups of the samples and their adsorption performance towards dibenzothiophene (DBT) were investigated. The RCSs with large surface areas (up to 2696 m²/g) and total pore volumes (up to 1.46 cm³/g) exhibited larger adsorption capacities than a commercial activated carbon, F400. Polanyi-Dubinin-Mane (PDM) model was applied to fit the adsorption data, which proved that micropore filling was involved during the adsorption process. Moreover, a good linear relationship was observed between the extra-micropore volume and adsorption capacity. Intra-particle diffusion (IPD) model was used to describe the kinetic data of DBT onto the adsorbents. The adsorption processes were divided into three stages according to the different diffusion parameter. The selective adsorption towards DBT in the presence of competing compounds was also investigated and the high selectivity of the RSCs towards DBT may be attributed to the large quantity of acidic oxygen-containing groups.