HARNESSING BIOGENIC ZINC OXIDE NANOPARTICLES FOR ECO-FRIENDLY ADSORPTIVE DETOXIFICATION OF METHYLENE BLUE DYE

Excessive release of synthetic dye into the environment has been reported by researchers and poses a major problem for water quality; thus, it is important to investigate inexpensive and less harmful strategies for treatment. In this study, pre-synthesized ZnO nanoparticles prepared by plant-mediated green method were used as an adsorbent to remove methylene blue (MB) from aqueous medium. Batch Experiments showed that the extent of methylene blue removal varied significantly with pH (3-12), dye content (5-30 ppm), contact duration (0-40 min), and adsorbent dosage (5-20 mg). A fast uptake in the beginning was followed by a steady region when the surface became saturated. The kinetic plots fitted best to the pseudo-second order model (R²≈0.99), whereby implies that the rate is mainly controlled by surface interaction rather than mere diffusion. The precision of the kinetic model was additionally evaluated through statistical parameters such as mean squared error (MSE) and root mean squared error (RMSE), which demonstrated the superior correlation and fitting accuracy of the PSO model. Among the equilibrium models tested, the Freundlich isotherm described the empirical findings more suitably, pointing towards a heterogeneous adsorption surface in contrast to a monolayer. Under the optimum conditions, the ZnO nanoparticles removed MB efficiently, suggesting that such leaf-extract-derived nanomaterials can serve as a simple and greener option for dye-laden wastewater.