The impact of annealing temperature on photocatalytic degradation performance of rhodamine B by montmorillonite/zinc-oxide nanocomposite

This paper investigates the impact of annealing temperature on the photocatalytic degradation efficiency of rhodamine B (rhB) using a montmorillonite/zinc-oxide (MMT/ZnO) nanocomposite. The MMT/ZnO nanocomposites, synthesized through a chemical method, are annealed for one hour at 300°C, 500°C, and 700°C. The study involves a comprehensive analysis of sample composition, surface morphology, and structure using various analytical methods, including Energy Dispersive X-ray Spectroscopy (EDX), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and Fourier Transform Infrared Spectroscopy (FTIR). RhB degradation efficiency is assessed by monitoring changes in dye concentration in the solution after exposure to UVC radiation, measured with UV-Vis spectroscopy. By-products resulting from the photocatalysis process are identified through LCMS analysis. The results demonstrate that MMT/ZnO annealed at 500°C (referred to as MZ@500) exhibits the highest capability for rhB decomposition, achieving a remarkable 95.5% degradation efficiency with 10 ppm of rhB and 0.1 g/L of MZ@500. Furthermore, this composite effectively fragments the dye’s chromophore structure into smaller, ring-broken compounds.