الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The main trend of this work is based on the desulfurization of diesel fuel using photocatalytic materials. Among the well-known semiconductor, cadmium oxide (CdO), zinc oxide (ZnO) and titanium dioxide (TiO2) have been paid the greatest interest in the photo catalysis technology.
This study has focused on the preparation of various structures of nano-photocatalytic materials
• Two cadmium oxides (CdO) as well as Two zinc oxides (ZnO) nanoparticles were prepared via both the chemical precipitation and auto-ignition methods.
• Titanium dioxide (TiO2) nanoparticles were prepared in two different structures via the chemical precipitation method from trivalent and tetravalent Ti salts.
All the prepared metal oxides nanoparticles were fully characterized by XRD, TEM, SEM, surface area analysis, UV/Vis- Spectrophotometery and Photoluminescence. The prepared materials were then used as photocatalysts for the removal of sulfur compounds; one of the major harmful pollutants in diesel fuels.
At the first place and based on the photoluminescence (PL) spectra, the CdO which was prepared by the precipitation method was fund to be the most active under visible light than the others.
The higher photo activity of this structure is dependant on its low rate in the recombination of the hole/electron pairs. The freshly prepared CdO was then utilized in the catalytic photochemical desulfurization process where different parameters were studied and the optimum conditions were next determined.
Several factors have influenced the catalytic photochemical desulfurization process of diesel fuels. These factors are:
• The effect of light source.
• The effect of the catalyst dosage.
• Effect of adding Oxidizing agent with different strengths and concentrations, as well as, the mixed oxidizing agents.
• The operational time of irradiation.
After all the prior conditions were comprehensively studied, the optimum conditions were selected based on the noted maximum removal% of sulfur compounds. In particular, the optimum conditions were determined as 7g/L of the catalysts, reaction time of 3h and oxidizing agent-to feed ratio 1 to 1. These conditions were next applied to evaluate the activity of all the other prepared structures under visible light, UV irradiation and sunlight spectrum. The ultimate sulfur contents in the final diesel fuels were accomplished via the solvent extraction procedures. Eventually, a diesel fuel with a sulfur content of 45 ppm was obtained after the removal of 99.61 wt % of the sulfur compounds from the original feedstock (11500 ppm) under LHL in case of cross current solvent extraction after catalytic photochemical process.
Also, a catalytic photochemical desulfurization process using TiO2 nanoparticles (source IV) under UV irradiation was reported at the end of this work. A diesel fuel with a sulfur content of 25 ppm was obtained after the removal of 94.38 wt % of the sulfur compounds from the feedstock (445 ppm).This value was obtained through the utilization of the diesel fuel of the lowest sulfur content from the first stage as a secondary feed. A catalytic photochemical process using the TiO2 nanoparticles (source IV) under UV irradiation was used to attain this goal at the end of this work.
A maximum sulfur removal of 98.11% was obtained by using CdO under the sunlight.
Finally, the results of this study are promising in terms of obtaining an increased sulfur removal efficiency compared to only photochemical or photocatalytic process. Thus, the process which is developed here has the potential of being more efficient and economical in removing sulfur from diesel feedstock.