Mechanochemical synthesis of AgI–BiOI@g-C3N4 heterojunction for the efficient degradation of cationic dye RhB under visible light irradiation

Abstract

The direct release of large quantities of textile dyes into natural water highlights the urgent need for effective pollution treatment strategies. In this situation, photodegradation emerges as a crucial and environmentally friendly technique for protecting the environment. In this study, a simple mechanochemical synthesis protocol was used for the preparation of a heterojunction based on the combination of AgI–BiOI and g-C₃N₄. The heterojunction was characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy combined with Energy Dispersive X-ray Spectroscopy (SEM/EDX), Fourier Transform Infrared Spectroscopy (FTIR), and Diffuse Reflectance Spectroscopy (DRS). The results of these studies demonstrated the successful formation of the heterojunction, which had excellent structural, textural, and optical properties. To better understand the degradation process of RhB dye over the photocatalyst, a thorough investigation of key parameters such as catalyst dosage, pH, initial dye concentration, scavenger, and reutilization was carried out. The heterojunction with the ratio (AgI–BiOI/g-C₃N₄ = 0.8) demonstrated remarkable efficiency in the degradation of RhB dye. Notably, the apparent degradation rate was found to be 14.5 times greater than that reached with the g-C₃N₄ alone. This significant enhancement in degradation performance suggests the potential of the synthesized heterojunction as an effective catalyst for environmental remediation applications.