Removal of sulphur from model gasoline by CuAgY zeolite: equilibrium, thermodynamics and kinetics

Abstract

In this study, the removal of thiophene from cyclohexane using ion-exchanged Y zeolites was investigated in a batch system by performing static tests. The effects of initial sulphur concentration, contact time and adsorption temperature on the removal efficiency were studied. Changes to the adsorbents before and after the adsorption were characterized by ICP-AES, XRD, N₂ physisorption, SEM, and TEM. The highest sulphur adsorption capacity of 60.98 mgS g⁻¹ for CuAgY was achieved at 323 K. The equilibrium data were well fitted by the Sips model and the kinetics of the adsorption process could be described by the pseudo-second-order model. Thermodynamic parameters were obtained from the models and indicated that the adsorption was spontaneous and exothermic. Modeling results also showed that the Marquardt's Percent Standard Deviation (MPSD) and the Sum of the Squares of the Errors (SSE) provided the best fitting results for isotherm and kinetic models, respectively. In addition, it was found that CuAgY could maintain 84.5% of the capacity for sulphur after twice regeneration.