Synthesis, Modification, and Application of Hollow Mesoporous Carbon Submicrospheres for Adsorptive Desulfurization

Hollow mesoporous carbon submicrospheres (HMCNs) have been successfully synthesized via a facile silica-assisted sol–gel strategy, which were further treated with KOH or/and HNO3 to obtain four adsorbents with different structures and surface properties for the removal of dibenzothiophene (DBT). KOH activation can effectively adjust the micro/mesoporous structure by increasing the number of micropores, and HNO3 oxidation can modify the surface properties by introducing oxygen-containing functional groups. HMCNs treated with KOH first and then HNO3 are the best for DBT removal with the adsorption capacity of 33.20 mg S·g–1, which is nearly 45% higher than that of activated carbon with the same treatment. Notably, the adsorption equilibrium can be achieved within only 5 min, much faster than active carbon owing to the existence of abundant mesopores favorable to the diffusion of DBT. The negative ΔG° from thermodynamics result suggests it is a favorable and spontaneous adsorption process.