Turnera diffusa and its novel application in the synthesis of ZnO semiconductor nanoparticles with high photocatalytic power

Water effluents are excessively contaminated by organic dyes, causing significant damage to the flora and fauna. In this research, photocatalysis was used for the removal of three organic dyes, methylene blue (MB), methyl orange (MO), and rhodamine B (RhB). ZnO nanoparticles biosynthesized through an eco-friendly route were used as photocatalysts, employing extracts of Turnera diffusa as the reducing agent of the metallic precursor in these nanoparticle syntheses. The nanoparticles were characterized to know their structure by Attenuated Total Reflectance Spectroscopy (ATR-IR), X-ray Diffraction (XRD), and X-ray Emitted Photoelectron Spectroscopy (XPS). Thermogravimetric Analysis (TGA) was used to evaluate the thermal behavior, the BET method was used to evaluate the specific surface area, the morphology was analyzed by Transmission Electron Microscopy (TEM), and finally, the TAUC model was used to obtain the energy gap by UltraViolet-Visible spectroscopy (UV-Vis) spectra. The photocatalytic activity results presented a 100% degradation in 180 and 50 min for MB and MO dyes, respectively. And a 77% degradation for RhB at 180 min. This indicates that the biosynthesized NPs are adequate for removing contaminants found in water.