A numerical model has been established to get insight the mechanism of phenol removal from water through adsorption/photodegradation dual process over activated carbon titania composite catalysts (AC-TiO2). AC-TiO2 catalysts were obtained through a straightforward coating of a homemade AC with titania nanoparticles (TiO2-NPs), and their textural characterization revealed the presence of titania nanoparticles (TiO2-NPs) scattered at the external macroporosity of the microporous AC support material. A new mathematical approach were established to comprehensively take into account the bulk/por /surface diffusion rate of the pollutant before adsorption within the microporous catalyst, and then intrinsic photodegradation near the externally located and UV accessible TiO2-NPs. Under different experimental conditions and using catalysts of different titania contents, the simulated kinetics readily fit well the experimental profiles, suggesting the actual application of the model to describe the adsorption/photodegradation dual process driven by the composite catalysts.