Adsorption of Cu(II) Ions from Aqueous Solutions using a Magnetite Biochar Composite Material

Water contamination from heavy metals, such as Cu(II) ions, poses severe threats to human health and the environment. This necessitates the development of efficient and eco-friendly treatment methods. In this study, a magnetite–biochar composite (MBC) was developed as an effective adsorbent for reducing Cu(II) ions from liquid waste. Biochar was produced through the pyrolysis of water hyacinth at 500 °C, while magnetite was synthesized using FeSO₄·7H₂O and FeCl₃·6H₂O with molar ratio of 1:2. The MBC was formed using a co-precipitation method and characterized by Fourier transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller, and vibration sample magnetometer instruments. FTIR analysis confirmed the presence of Fe–O bonds, and XRD detected Fe₃O₄ peaks, confirming the successful integration of magnetite into the composite. The MBC exhibited a surface area of 72.54 m²/g and a saturation magnetization of 19.10 emu/g. Optimal Cu(II) ion adsorption occurred at pH 6 and a contact time of 60 min. Adsorption kinetics followed the pseudo-second-order model, and isothermal analysis aligned with the Sips model, indicating an adsorption capacity of 75.73 mg/g. These results demonstrate MBC’s excellent potential as a sustainable and effective adsorbent for treating Cu(II)-contaminated wastewater, offering an environmentally friendly solution to heavy metal pollution.