The application of modified walnut shell with magnetite nanoparticles as an adsorbent for the removal of organic dye fuchsin from aqueous solutions

Hard walnut shells, once considered waste, have emerged as valuable materials for environmental applications. Traditional adsorbents for dye removal, like activated carbon, face limitations such as low adsorption capacity and environmental concerns. This study explores the potential of walnut shells modified with magnetite nanoparticles (Walnut Shell@Fe3O4) as an eco-friendly adsorbent for fuchsin dye removal. Key objectives include characterizing the modified walnut shell using techniques like FT-IR, SEM, BET, XRD, XPS, and TEM. The adsorption performance shows a capacity of 204.08 mg/g and a removal rate of 99.10%. The study investigates the effects of pH, contact time, adsorbent dosage, dye concentration, ionic strength, and temperature on the adsorption process. Kinetics and isotherm analyses reveal that the adsorption follows pseudo-second-order kinetics and conforms to the Langmuir isotherm model. Thermodynamic parameters indicate that increased temperature enhances adsorption, confirming an endothermic process. Overall, the magnetite nanoparticle-modified walnut shell demonstrates an effective and rapid method for removing fuchsin dye from water, addressing the limitations of traditional adsorbents.