Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Organic Chemistry

The current research work reports the preparation of an organic based composite structure as a novel catalyst for the photocatalytic desulfurization of a petroleum gas oil fraction. The preparation of the composite material had contained two subsequent steps. In the first one a polystyrene polymer was prepared via the high internal phase emulsion polymerization technique. The formation of polymer structure has been then verified through the Fourier Transform infrared (FT-IR) analysis. The molecular weight of the polymer was also determined and was found to be 68 x 104 g/ mole. The second step of obtaining the composite structure had been then executed, in which different percentages of zinc metal nanoparticles were loaded onto the polystyrene (catalyst support). The electroless platting technique was the utilized method during the step of loading the metallic zinc particles on the support. The energy band gap measurements and surface characteristics of the prepared composites were afterward determined. The photocatalytic activity of the prepared composites versus the desulfurization of gas oil was next tested. Nearly one-fifth of the sulfur content of the gas oil feedstock had been removed by the composite which included zinc metal as 50% of its composition. The effect of the styrene concentrations in the polymers which are the support layers in the two prepared composites (contain 50% Zn), on their photoactivity was then studied. The composite which made of a polymer of a higher molecular weight had exhibited better desulfurization rate under constant operating conditions.This composite was then forward for the next stage in which the effect of the different desulfurization parameters were studied. Particularly the effect of using oxidizing agent during the sulfur removal as well as the reaction time and catalyst dose were the main investigated variables. Oxidative desulfurization using a catalyst dose of 10 g/L for 3h had exhibited the highest level of desulfurization about 30 wt. %. The ultimate desulfurization of the gas oil was acquired via a subsequent solvent extraction process using acetonitrile. A maximum desulfurization percentage of 97% was obtained using solvent-to-feed ratio (S/F) of 4:1 based on cross-extraction sequence. The sulfur content in the final product after the presented method has been 285 ppm of 7570 ppm for the started feedstock gasoil

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