Zinc Chloride Activated Mesoporous Carbon Nanospheres with Extremely Large Surface Area as Potential Adsorbents for Fuel Desulfurization

Porous carbon nanosphere (PCNS) with extremely large surface area and mesoporous structure was synthesized as a high-performance adsorbent for dibenzothiophene (DBT), a model sulfur compound in fuels. The structural and textural properties of PCNS were characterized by N2 sorption and transmission electron microscope, and the results indicated that the activated PCNS possessed the nanospherical morphologies and superior porosity with high surface area (~3000 m g) and large pore size (> 2 nm). The influence factors on the adsorption capacities of PCNS were systematically investigated, including pore structures, adsorption temperature, contact time and adsorbent dosage. The PCNS material activated with a ZnCl2/carbon mass ratio of 4 : 1 had the highest adsorption capacity at room temperature with a adsorbent concentration of 0.4 g L. The adsorption data at equilibrium depicted a Freundlich isotherm, and the adsorption kinetics indicated that the adsorption process obeyed a pseudo-second-order rate equation. The adsorption rate was controlled by three rate-determining steps. Additionally, PCNS could be regenerated by heating at 350 ̊C in N2 atmosphere and the regenerated adsorbent also exhibited a good adsorption capacity for DBT.