Characterization of ZSM-5 modified with niobium pentoxide: the study of thiophene adsorption

zsm-5 adsorbents impregnated with nb2o5 were applied in the sulfur removal in the form of thiophene, refractory substance of difficult removal of liquid fuels. for this purpose, a model fuel containing iso-octane contaminated with thiophene in concentrations of 877.5 to 1155 ppmw was prepared. the samples were characterized by x-ray diffractometry (xrd), fourier transform infrared (ftir) and fourier transform-raman (ft-raman) spectroscopies for confirmation of the adsorbents, being prioritized the adsorption study with that containing 5 wt.% of niobium pentoxide, because it showed a greater capacity for removal of thiophene. the best results of adsorption were achieved at 353 k, a longer time to reach equilibrium was observed. under these conditions, the best kinetic fitting was achieved using the equation of pseudo-second order, demonstrating the domain of the phenomenon of chemisorption. while under lower temperatures, the diffusion model presented a better approximation of the experimental results. also, the increasing of temperature did enhance spontaneous processes.