Biosynthesis and photocatalytic performance of Cumin extract-mediated ZnO nanoparticles with mechanistic investigation of degradation pathways

The purpose of the study was to investigate novel and green-synthesized ZnO NPs derived from C. cyminum seeds for photocatalytic degradation of the Direct Yellow 86 dye under UV irradiation. The green catalyst cumin-derived Zinc Oxide NPs (GC-C-ZnO NPs) were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and X-Ray Diffraction (XRD). A Box-Behnken Design (BBD) determines optimal conditions for DY86 removal, achieving 94% efficiency at pH 11.0, dye concentration of 30 mg L^-1, catalyst dose of 0.12 g L^-1, and a time of 30 min. The predictive model was statistically validated by analysis of variance (ANOVA), confirming a high correlation coefficient (R² 0.99). Significance was also verified by [Formula: see text] 0.99 and [Formula: see text] 0.98 values. The model and all parameters exhibited exceptional statistical significance (F-value 281.00, P-value < 0.0001). Liquid chromatography-mass spectrometry (LC-MS) analysis confirms diminished peaks at m/z 318.70 after photocatalysis by the GC-C-ZnO NPs. This investigation successfully advanced an efficient, eco-friendly photocatalytic system for enhanced water and wastewater purification. The study demonstrates that GC-C-ZnO NPs provide an efficient and eco-friendly photocatalytic system for the removal of organic dyes from textile wastewater.