The present research deals with the development of a new heterogeneous photocatalysis system for disinfection of bacteria from wastewater by using TiO2 graphene (TG) nanocomposite sensitized with tetrakis(4-carboxyphenyl)porphyrin (TCPP). The disinfection of wastewater using this photocatalyst is not reported in the literature yet. All the synthesized materials were thoroughly characterized by Raman, XRD, DRS, BET, and SEM analysis. The optimum content of graphene in the TiO2 graphene nanocomposite was determined by photocurrent responses of prepared photocatalysts. Subsequently, the photocurrent measurements demonstrate that the TiO2 graphene nanocomposite with 3% graphene content has higher photoactivity. Furthermore, sensitization of the TiO2 graphene nanocomposite with porphyrin (TGP) is successfully capable to develop a new type of photocatalyst system for disinfection of bacteria with moderate to high yields in visible light irradiation. (C) 2015 Elsevier B.V. All rights reserved.