Methylene blue (MB) is a chemically stable and poorly biode-gradable contaminant in wastewater. In this work we used its decomposition reaction as a model to evaluate the photocatalytic activity of the as-prepared membranes. Typically, 8.0 mg of photocatalyst (pure TiO2 nanofibers and CNTs/TiO2 nanofiber membrane) was added to 100 mL of MB solution (3.0 mg/L). The resulting mixture was irradiated by a 10 W ultraviolet lamp (wavelength: 254 nm). The concentration of the MB solution was monitored at regular intervals of 10 min by a UV–vis spectrometer.