Document Type : Full research article
Author
Assocate Professor Department of Chemical Engineering, Payam Noor Uiversity, Tehran, Iran
Abstract
Heavy metals such as lead, nickel, and cadmium present in industrial wastewater pose serious environmental and public health risks. In this study, magnetic iron oxide nanoparticles with a crystallite size of 18 nm were synthesized via a co‑precipitation method and evaluated for the simultaneous removal of Pb(II), Ni(II), and Cd(II) from aqueous solutions. Characterization was performed using X‑ray diffraction (XRD), optical microscopy, and magnetization measurements. Batch adsorption experiments were conducted at 25 °C to investigate the effects of pH (3–9), adsorbent dosage (0.3–1.0 g/L), and contact time (5–30 min). The key novelty of this work is the achievement of high removal efficiencies under acidic conditions (pH = 3) without any surface modification: 97% for Pb(II), 98% for Ni(II), and 91% for Cd(II), indicating strong potential for treating acidic industrial effluents without pH adjustment. Increasing the pH to 9 reduced the removal efficiencies to 45% for Pb(II), 58% for Ni(II), and 41% for Cd(II).The optimal adsorbent dosage was determined to be 0.5 g/L; higher dosages reduced efficiency due to particle agglomeration. Adsorption equilibrium was reached within 25–30 minutes. Kinetic data showed an excellent fit with the pseudo‑second‑order model, while equilibrium data were well described by the Langmuir isotherm, indicating monolayer chemisorption on homogeneous adsorption sites. The maximum adsorption capacities were 3.42, 7.28, and 1.41 mg/g for Pb(II), Ni(II), and Cd(II), respectively. Rapid magnetic separation and reusability make these nanoparticles an efficient and cost‑effective adsorbent for the treatment of industrial wastewater.
Keywords
- Iron oxide nanoparticles
- heavy metal removal
- wastewater treatment
- adsorption
- magnetic separation
- industrial effluent
Main Subjects
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