Titanium dioxide nanotubes TNTs were synthesized by anodization in a fluoride-based electrolyte, TNTs are commonly working as photocatalytic under ultraviolet UV irradiation via its wide bandgap, and it was expanded under visible light irradiation by doping with other metals or metals oxides, herein TNTs were doped by copper oxides Cu2O and CuO to produce copper oxides /titanium oxide nanotubes CuOx /TNT. The prepared catalysts (TNTs and CuOx/TNT) were characterized by XRD, FTIR, SEM and, EDX, while catalysts activity was investigated for oxidization of Dibenzothiophene DBT under ultraviolet UV and visible light VL irradiations, the feedstock is model fuel (heptane contains DBT as a sulfur component) was oxidized by hydrogen peroxide H2O2. Results showed that TNT has a moderate catalysis effect under UV irradiation and a low catalysis effect under VL irradiation. CuOx/TNT catalyst exhibited good sensitivity for VL radiation. The study investigated the effect of initial DBT concentration, oxidant dosage, reaction temperature, contact time, and type of irradiation on oxidation desulfurization ODS reaction by using TNT and CuOx/TNT catalysts, the results showed that DBT removal efficiency was increasing with temperature (56.2, 80.4 and 91.2 at 40,50, and 60 °C respectively at 100 minutes) and oxidant amount ( 66.4, 80.4, and 86.1 by adding 5,10,15 ml of oxidant respectively at 100 minutes) while it decreases with the increasing initial BDT concentration (94.8, 80.4, and 86.1 when using 100,150, and 200 ppm as initial DBT concentration at 100 minutes). The kinetics calculations exhibited that ODS reaction under VL irradiation follows pseudo-first-order reaction at CuOx/TNT catalyst with reaction rate constants of 0.00076, 0.0108, and 0.0141 min-1 at 40,50, and 60°C respectively, the activation energy for the reaction is 26.8 kJ/mol, negative ΔS (-0.218 kJ/mol.K) and positive ΔH and ΔG for DBT oxidation under UV irradiation. تفاصيل المقالة

Cobalt and Molybdenum oxides supported on graphene catalyst CoMo/G were prepared then its activity for hydro-desulfurization reaction HDS was examined in this research. The catalyst was characterized by X-ray diffraction XRD, Fourier transform infrared spectroscopy FTIR, and energy dispersive spectroscopy EDS while surface morphology was tested by scanning electronic microscopy SEM and atomic force microscopy AFM. The texture properties (specific surface area and pore volume) are measured by the Brunauer, Emmett and Teller BET method. The catalyst activity investigation was conducted by heavy naphtha HDS reaction in a fixed bed reactor, this study investigated the effect of temperature (250-325) ºC, Liquid Hourly Space Velocity LHSV (3-6) hr.-1 and hydrogen partial pressure (1-1.3) MPa while gas/oil ratio was kept a constant 50 ml/ml, these variables’ impact was designed and analyzed by Taguchi design of experiment DOE with using MINITAB software. The results showed that sulfur removing percentage SR% increases with both increasing of temperature and hydrogen partial pressure whereas LHSV has the opposite effect on SR%. HDS reaction kinetics parameters were estimated by experiment results employing Levenberg-Marquardt and SPSS software version 20; the results showed the HDS reaction which followed 1.863 order, reaction rate constant and activation energy, is 32.309 kJ/mol. تفاصيل المقالة