In this study, Manganese (Mn) and Nickel (Ni) doped on titanium dioxide (TiO2) were loaded on Multi-Walled Carbon Nanotubes (MWCNTs). These catalysts were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), X-ray energy dispersive spectrometer/Mapping (EDS/Map), Brunauer, Emmett, Teller (BET)/Barrett, Joyner, Halenda (BJH) and Diffuse Reflectance Spectroscopy (DRS) methods. A batch reactor was designed and photoactivity of these materials prepared under visible light irradiation was tested using dibenzothiophene (DBT). The Response Surface Methodology (RSM) based on Box-Behnken Design (BBD) was used to evaluate parameters including catalyst mass (g), time (h) and dopant percentage (wt%). The best point for maximum degradation efficiency was obtained under optimum conditions for Mn/TiO2/MWCNTs and Ni/TiO2/MWCNTs catalyst masses of 0.25 and 0.22 (g), time of 5.30 and 4.56 (h), and dopant percentage of 4.22 and 7.82 (wt%) with an efficiency of 92.82 and 98.26%, respectively. Under optimal conditions for the degradation of DBT sulfur, was investigated desulfurization of gas condensate. The highest desulfurization efficiency was obtained by Ni/TiO2/MWCNTs catalyst at 89.11%. The results of kinetic studies show that the Blanchard model has the best agreement with the experimental data. [GRAPHICS] .