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The search for alternative processes for the removal of sulfur compounds in fuels is a constant, as environmental legislation around the world is becoming increasingly rigorous regarding reductions in the fraction of these compounds in fuels. This study evaluated the adsorptive capacity of zeolite ZSM-35 pure and impregnated with 2.5% and 5% molybdenum in the removal of the thiophene, organosulfur compound, of a model gasoline. The materials were prepared via wet impregnation and characterized by XRD, SEM, thermal analysis (TG/DTG). Adsorption kinetics were performed at temperatures of 303 K and 313 K in a batch system under agitation of 140 rpm for 12 hours. The kinetics of adsorption was evaluated by kinetic models of pseudo first order, pseudo second order, intraparticle diffusion and Elovich. The results showed that the increase in temperature and the concentration of molybdenum in the structure of the zeolite has an influence on the increase of the sulfur removal efficiency of the gasoline.

The oxidative desulphurization is considerate one of the most promising methods to remove sulphurous compounds of fossil fuels, because it’s a process that can be realized under smooth conditions, ambient temperature and atmospheric pressure. The desulfurization process makes rusty compounds, where the sulfur goes from a divalent state to a hexavalent state, from this your extraction becomes possible using a solvent, for example the acetonitrile. The most used oxidant in this process is the hydrogen peroxide, having advantages, as your capacity of oxidize some compounds directly, thermal stability and the absence of problems with the mass transfer. The solid catalysts for the oxidative desulfurization are made with a base of transition metals. The molybdenum it’s a transition metal and your oxides can be used in great technologic application. The vanadium has a lot of applications as oxidative catalyst in chemical industries and also the environmental industries too. The reactions were carried out with 6 samples at a temperature of 60oC and 24°C ambient temperature, with and without catalysts, in order to analyze the efficiency of the process at different temperatures. The analyzes of the physico-chemical properties are of great importance to analyze possible changes because of the reactions. The proposed method to quantify the sulfur content was made, but because of the unsatisfying precipitation of the sulfurous compounds your efficiency could not be calculated. The oxidative desulfurization was found to be a method that does not affect the physico-chemical properties of the diesel engine, both the density and the viscosity remained in the pattern in all samples except when it was used in the MoO3 as catalyst, which caused an increase in its acidity level.

The concentrations of heavy metals in two kinds of Brazilian coals at 100° C (acid digestion) and at 850° C were studied (ashes the obtained in muffle furnace with and without addition of limestone). Data were analyzed by flame atomic absorption, using the air acetylene flame. For Pb, Zn, Ni, Mn and Cu the metal concentration obtained the acid digestion were higher than metal concentration were obtained in tests in the muffle furnace. This behavior observed in the muffle furnace occurs because these metals are fixed in stable sulfated compounds in the ashes, which are difficult to dissociate at flame temperature, and also due to the volatile character of the metals, mainly Pb and Zn. There was a constant concentration in the ashes in of Cr the acid digestion and muffle furnace tests. Results from tests using an XRD apparatus indicated, he formation of sulfated compounds in the ashes for both. coals. The analysis using microprobe electronic showed retention of metals like Ni, Mn, Cu, Fe, Ti and Ca. For both coals, the low mobility of most of the metals studied occured due to the alkaline pH of sulfated ashes. These metals in the ash from coal combustion in fluidized bed reactor were also studied and showed similar results, enabling a scale-up to pilot scale.