Adsorption of Dibenzothiophene by Walnut Shell-Activated Carbon/Chitosan/Iron Nanocomposite: Kinetics, Equilibrium, Thermodynamics and Mass Transfer Modeling

Removing sulfur and sulfur compounds from liquid fuel is one of the most important research topics. In this research, activated carbon was prepared by chemical activation from walnut shells, then modified by iron nanostructure and chitosan separately and together, and used to remove dibenzothiophene from isooctane fuel. BET, EDX-SEM, and FTIR analyses were used to investigate the adsorbent. Equilibrium experiments showed that the adsorption process is a single layer, and the maximum adsorption capacity is 285.71 and 178.57 mg of dibenzothiophene per gram of adsorbent modified by iron nanostructure and per gram of adsorbent modified by iron nanostructure and chitosan, respectively. The results of kinetic data showed that the pseudo-second-order kinetic model is consistent with the experimental result. To determine mass transfer parameters, the mathematical model of film-pore-surface diffusion model was used by MATLAB software and it was observed that external mass transfer and pore diffusion stages are more important.