Sulfated (5wt.%) ZrO2 and non-sulfated ZrO2 modified by NH4VO3 using incipient wetness impregnation technique to achieve a loading of 5wt.% V2O5 were thoroughly characterized by means of X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy, N2 sorptiometry, particle size analyzer and pyridine-FT-IR that was used to investigate the acidity of the samples. Degradation of direct blue-1 (DB) dye was tested for the effectiveness of the samples. The results revealed that DB degradation was highly improved with V supported on ZrO2-SO4 and showed a conversion comprises of 95% after UV irradiation (emitting at 365 nm) for 60 min exceeding that of SO4 free ZrO2 sample (68%) obtained at the same period of illumination. This was due to the large surface area (183 m 2 g-1), small crystallites size and presence of basic sites namely O2 − and OH − moieties, those take part in the reaction as additional oxidizing agents. The photocatalytic degradation of DB was found to follow first order rate kinetics. More information on the activity, surface texturing, kinetics and TOC removal were well evaluated, compared and discussed for all samples.