Adsorção de tiofeno e derivados utilizando matrizes sólidas contendo nióbio

Abstract

In this work, were studied based materials rice hull ash (RHA) and ZSM-5 containing niobium pentoxide (Nb2O5), in the sulfur adsorption of liquid fuels. For this porpuse, model fuels was prepared containing iso-octane contaminated with thiophene, benzothiophenes and dibenzothiophene. The adsorbents obtained were characterized by the X-ray diffraction, infrared, scanning electron microscopy, nitrogen physisorption and thermal analysis techniques, was also prioritized the study of adsorption of S with those containing 5% niobium pentoxide, because of the greater thiophene removal capacity presented. The best results were achieved adsorption at 80 °C, after 50 minutes, achieving removals of 49 % and 79 % for the CCA and ZSM-5 based adsorbents, respectively. Under these conditions, the best fit was achieved using the kinetic equation of pseudo-second order, demonstrating mastery of the phenomenon of chemisorption. While under lower temperatures, the diffusion model showed better approximation of the experimental results. Moreover, the increased temperature favors the adsorption of spontaneous processes thiophene. For larger molecules (such benzothiophene and dibenzothiophene) was observed a reduction of the level of removal of S (around 84 %), indicating that the adsorbent materials have high selectivity so. This was confirmed in adsorption experiments binary solutions of thiophene, and dibenzothiophene benzothiophenes.