Bio-synthesis of nano-zero-valent iron using barberry leaf extract: classification and utilization in the processing of methylene blue-polluted water

Abstract This study explores an eco-friendly and efficient approach to remediate water contaminated with methylene blue dye by leveraging green adsorption techniques. Specifically, we employed barberry leaf extract, a renewable biomass resource, as a reduction and capping agent to synthesize nano-zero-valent iron (nZVI) for targeted methylene blue dye adsorption. State-of-the-art analytical methods, including transmission electron microscopy (TEM), steady-state absorption spectroscopy, scanning electron microscopy (SEM), and X-ray crystallography, were employed to elucidate the structural and morphological properties of the synthesized nZVI. The study achieved a remarkable adsorption efficiency of 97.52% at optimal pH 7 and 30 °C conditions, highlighting its potential for real-world applications. Kinetic analysis revealed that the adsorption process follows a pseudo-first-order model, aligning well with the principles of biorefinery systems. The Freundlich isotherm model was effectively used to describe the adsorption process, with a maximum sorption capacity of 56.37 mg/L. Optimal system constants were also derived, offering valuable insights for scaling the process. Significantly, our nZVI showed high reusability, affirming its suitability as a cost-effective and environmentally responsible adsorbent. The methodology and findings of this study have promising implications for the biomass conversion industry, particularly in the design of sustainable water treatment technologies.