Alginate-coated cobalt ferrite nanocomposite for preconcentration of heavy metals using dispersive solid phase extraction

Abstract

Environmental pollution is becoming increasingly severe due to the widespread release of harmful substances, including heavy metals (HMs). HMs are of particular concern because they persist in the environment and bioaccumulate in living organisms, resulting in various health complications and ecological damage. In the current work, cobalt ferrite nanoparticles (CoFe₂O₄-NPs) were synthesized via a green sol–gel method using an aqueous extract of M. indica leaves. The synthesized CoFe₂O₄-NPs were used to fabricate an alginate-coated nanocomposite (Alg/CoFe₂O₄-NC) via an in situ method. The synthesized CoFe₂O₄-NPs and Alg/CoFe₂O₄-NC were characterized using advanced analytical techniques to assess their crystalline structure, crystallite size, degree of crystallinity, surface functionality, morphology, topography, surface charge, stability, and zeta size distribution. Alg/CoFe₂O₄-NC was employed to develop a novel dispersive solid-phase extraction (DSPE) method for simultaneous detection of cadmium (Cd), manganese (Mn), nickel (Ni), and lead (Pb) by flame atomic absorption spectrometry. Many experimental factors, including pH, nanocomposite dose, sample volume, eluent composition, eluent concentration, and eluent volume, were examined to maximize efficiency. The developed Alg/CoFe₂O₄-NC/DSPE/FAAS method showed limits of detection (LODs) for Cd (0.047 µg L⁻¹), Mn (0.23 µg L⁻¹), Ni (0.028 µg L⁻¹), and Pb (0.107 µg L⁻¹).