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

## TL;DR

A new nanocomposite material was developed to efficiently extract and detect trace amounts of heavy metals from water samples.

## Contribution

A green-synthesized alginate-coated cobalt ferrite nanocomposite was introduced for sensitive and eco-friendly heavy metal preconcentration.

## Key findings

- The Alg/CoFe2O4-NC method achieved low detection limits for Cd, Mn, Ni, and Pb.
- The nanocomposite was characterized for structure, morphology, and stability.
- The method is rapid, reusable, and suitable for trace metal analysis in aqueous samples.

## 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).

A natural polymeric ferrite adsorbent enables efficient dispersive solid-phase extraction, providing a rapid, reusable, and environmentally friendly analytical approach for the sensitive preconcentration of trace heavy metals from aqueous samples.