The photocatalytic capabilities of the TiO2–GO membrane and control membranes in decomposing organic dyes were tested in temperature-controlled batch photodegradation experiments. As shown in Fig. 2(a), this system consists of a reactor with the membrane attached to a supporting stand in the reactor, a water bath (Neslab, Newington, NH) to maintain the reactor at a constant temperature, and a UV/sunlight source to conduct the photode- gradation experiments. The UV light was generated by a 150-W, built-in ballast UV lamp (Sigma-Aldrich, St. Louis, MO), and the sunlight was generated by a 70-W, full-spectrum light bulb (Blue- Max Lighting, Jackson, MI). Methylene blue (MB), a positively charged dye with a molecular weight of 284 Da, was selected as a representative organic contaminant. MB concentration was analyzed using a UV–vis spectrophotometer at a wavelength of 665 nm.