Graphene/TiO2/ZSM-5 composites synthesized by mixture design were used for photocatalytic degradation of oxytetracycline under visible light: Mechanism and biotoxicity

The mechanism of OTC degradation can be described as follows. At first, the OTC molecule was adsorbed onto the surface of GTZ material. The conduction band electron (e−) and valence band holes (h+) are generated when aqueous GTZ suspension is irradiated with visible light. The generation of (e−/h+) pair leading to the formation of reactive oxygen species. The OH radical and O2− can oxidize OTC molecular, resulting in the degradation and mineralization of the organics.