ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis of magnetic Fe₃O₄@SiO₂ nanoparticles decorated with polyvinyl alcohol for Cu(II) and Cd(II) ions removal from aqueous solution

Ali Akbar Asgharinezhad, Mohsen Esmaeilpour, and Majid Ghahraman Afshar

Chemistry and Process Research Department, Niroo Research Institute, Tehran, Iran

E-mail: mesmaeilpour@nri.ac.ir

Received: 5 August 2023  Accepted: 27 January 2024

Abstract:

This work describes fabrication of Fe₃O₄@SiO₂ core–shell nanoparticles functionalized with polyvinyl alcohol (PVA) and its application for the removal of Cu(П) and Cd(П) ions. Surface chemistry and morphology during functionalization of Fe₃O₄@SiO₂ NPs were evaluated utilizing Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, vibration sample magnetometer, transmission electron microscope, field emission scanning electron microscope, and dynamic light scattering. The performance of the PVA-modified magnetic nanoparticles for Cu(П) and Cd(П) ions removal was evaluated by changing five process variables: contact time of adsorbent, temperature, pH, adsorbent dosage, and initial concentration. The highest removal efficiency was observed at a pH value of 7, an adsorbent dose of 15 mg, an initial concentration of 0.5 mmol/L, and a contact time of 25 min for Cu(II), while these values are 7, 15 mg, 0.4 mmol/L, and 20 min for Cd(II), respectively. The adsorption equilibrium is well explained by Langmuir adsorption isotherms which namely monolayer adsorption. The adsorption isotherm studies of the novel adsorbent in removing target ions from wastewater showed that the maximum adsorption amounts of Cu(П) and Cd(П) were 1.57 and 0.99 mmol/g at 35 °C. According to the calculated parameters and fitting model, the kinetics adsorption data are well fitted to the pseudo-second-order kinetic model which suggests that the main rate-determining step was chemisorption’s. According to the results, the prepared composite possesses excellent adsorption efficiency to be applied for the preconcentration of target heavy metal ions in the field of water treatment. The new adsorbent is completely separated from the aqueous solution under external magnetic field for five consecutive cycles without significant loss of activity.

Keywords: Fe3O4; SiO2 nanoparticles; Polyvinyl alcohol; Removal of heavy metal ions; Adsorption isotherms; Adsorption kinetics; Magnetic separation

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-024-03350-4

Chemical Papers 78 (6) 3799–3814 (2024)