In this study, photocatalytic degradation of an organic azo dye, Acid Red 1, has been measured under UV irradiation in an aqueous dispersion of TiO2 to find optimal conditions for a photocatalytic membrane reactor (PMR) operation. Furthermore, to separate and recover the anatase TiO2 photocatalyst, low-pressure microfiltration using hollow fiber membranes was applied. Since the main limitation in dead-end microfiltration with hollow fibers is the formation of an external specific deposit on the outer surface of the membrane, cake layer formation was also studied. The changes in various parameters, including decolorization, chemical oxygen demand, total organic carbon, pH and turbidity of the solution were measured and analyzed during the process. Experimental results indicate that the solutions containing the model azo dyes could be successfully decolorized using the photocatalytic process studied.(c) 2013 Elsevier B.V. All rights reserved.