Abstract
Novel titania supported activated carbon catalysts were prepared by a straightforward titania coating route of a microporous activated carbon (AC) derived from shea nut shells, and investigated in phenol photocatalytic degradation. The proposed coating method enables a fixation of the preformed titania anatase nanoparticles (TiO2 NPs) in the external porosity thus allowing their accessibility towards UV irradiation, without causing any reduction of the AC specific area. Interestingly, the coating treatment reshapes the porous texture of the as-prepared TiO2–AC composite materials resulting in an improvement of the adsorption capacity and the formation of an additional mesoporosity on the TiO2-AC surface. Photocatalytic experiments carried out in a batch reactor led to 97% elimination rate of phenol in an aqueous solution with the AC catalysts containing TiO2 NPs in the range from 11 to 34 wt%. The photodegradation performance of the TiO2–AC catalysts was maintained over several successive cycles, without the need of any regeneration treatment. Considering both the textural and microstructural features of the composite materials and their associated phenol removal kinetics, in this paper, we provide new insights into phenol photodegradation pathway involving an effective coupling of adsorption and photodegradation functionalities, resulting in a photo-assisted regeneration mechanism of the catalyst.