Recycling of spent primary batteries for the synthesis of ZnO-based photocatalysts: the role of graphene

Abstract

Primary batteries, particularly alkaline and zinc–carbon (Zn-C) types, have a relatively short service life and are frequently discarded in landfills, leading to potential environmental risks and health concerns.To address this issue, we synthesized ZnO-based photocatalysts coupled with graphene, graphitic carbon (g-C₃N₄), and a graphene/g-C₃N₄ hybrid via a hydrothermal method, using ZnO, and graphene recovered from spent primary batteries. Techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and diffuse reflectance ultraviolet-visible spectroscopy (UV-vis DRS) have been employed to elucidate the strong influence of graphene on the crystal structure, surface morphology, optical characteristics, and photocatalytic performance of the synthesized composites. The results demonstrate that the ZnO/graphene catalyst exhibits 1.5- and 1.7-fold higher rifampicin degradation efficiency than ZnO/graphene/g-C₃N₄ and ZnO/g-C₃N₄ under the same conditions.