Photo Catalysis Desulfurization at Copper Oxides /Titanium Oxide Nanotubes Under UV and Visible Light Irradiation

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.