Sustainable Removal of Methyl Violet from Aqueous Solution Using Banana Peel Extract-Modified Magnetite Adsorbent

Abstract

The textile industry generates large volumes of dye-containing effluents, with Methyl Violet (MV) among the most toxic and persistent pollutants due to its carcinogenicity and resistance to degradation. In this study, a green adsorbent based on magnetite (Fe₃O₄) modified with Banana Peel (BP) extract was synthesized via reverse co-precipitation, where BP functions simultaneously as a natural reducing, stabilizing, and surface-functionalizing agent. Structural characterization using X-Ray Diffraction (XRD) and Fourier-Transform Infrared (FTIR) spectroscopy confirmed the crystalline spinel structure of Fe₃O₄ and the incorporation of organic functional groups (-OH, C=O) from BP onto its surface. Adsorption experiments demonstrated a maximum capacity of 135 mg·g^-1 for MV at pH 6.0, with data fitting well to the Langmuir isotherm model, indicating monolayer adsorption. Furthermore, Fe₃O₄-BP achieved over 95% MV removal in simulated wastewater and could be magnetically separated and reused. These findings emphasize the dual role of agricultural waste as both a sustainable reagent in nanoparticle synthesis and as a performance enhancer for adsorption, underscoring the potential of Fe₃O₄-BP as a cost-effective and eco-friendly material for wastewater treatment.