Magnetic Nanostructures for the Removal of Emerging Organic and Inorganic Pollutants: An Overview of Applications in Contaminated Water

TL;DR

This paper reviews magnetic nanomaterials for water treatment, showing high efficiency in removing pollutants like dyes, pharmaceuticals, and heavy metals.

Contribution

The paper provides a comprehensive overview of synthesis methods and performance metrics for magnetic nanomaterials in water remediation.

Findings

Magnetic nanomaterials achieved up to 100% removal of organic contaminants like dyes and pharmaceuticals in lab conditions.

Adsorption capacities for heavy metals like Pb(II) reached 909.1 mg·g−1 with 90–99% efficiency.

Synthesis methods like coprecipitation and green methods were compared for their impact on particle size and magnetic properties.

Abstract

Magnetic nanomaterials (MNMs) have been adopted as effective platforms for water remediation owing to their excellent surface-area-to-volume ratios, tunable surface chemistry, and magnetic separability. This review highlights the recent progress made in the synthesis, properties, and environmental applications in the removal of organic and inorganic contaminants using magnetic nanoparticles (MNPs) and one-dimensional magnetic nanofibers. Demonstrated removal rates of organic contaminants such as dyes, pharmaceuticals, and pesticides are often up to 85–100% under laboratory conditions, with adsorption capacities of 580 mg·g−1 for melanoidin, 397.43 mg·g−1 for Congo Red, and 392.64 mg·g−1 for tetracycline. For heavy metals such as As(V), Cd(II), Cr(VI) and Pb(II), efficiencies are generally between 90–99% with maximum adsorption capacities of 909.1 mg·g−1 for Pb(II). In particular, the review compares major synthesis routes such as coprecipitation, hydrothermal, solvothermal, thermal decomposition, sol–gel, microwave, and green methods by evaluating their effect on particle size (6–50 nm), magnetic properties (saturation magnetization up to ~101 emu·g−1), and removal performance. The four principal mechanisms are described in this paper—adsorption, filtration, transformation, and photocatalysis—giving special emphasis to the advantages of magnetic recovery and advanced oxidation processes. Although most studies remain at the laboratory scale, MNMs demonstrate strong potential for scalable wastewater treatment, provided that toxicity, life-cycle impacts, and matrix effects are carefully evaluated.

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