Magnetic Iron Oxide and Ferrite Nanomaterials for Electrochemical Sensing and Remediation of Hazardous Water Contaminants

Abstract

Toxic metals, metalloids, pesticides, drug residues, dyes and pathogens occur together in natural and waste waters, and the health-based guideline values for several of them sit at the µg/L level. Meeting such limits calls for sensitive measurement and for treatment that can be recovered and reused, yet the two are usually studied apart. Magnetic iron oxides, spinel ferrites and their hybrids can serve both purposes: a tunable surface supplies recognition or binding, and magnetism allows preconcentration and recovery. This critical narrative review sets reported performance against drinking-water guideline values. An Au-decorated MnFe 2 O 4 electrode, for example, detected As(III) at 3.37 µg/L against a 10 µg/L guideline, and PEI-functionalised Fe 3 O 4 adsorbed up to 60.98 mg/g Pb(II). We relate material design (Fe 3 O 4 /γ-Fe 2 O 3 , MFe 2 O 4 , core–shell and carbon hybrids) to electrochemical transduction and to removal mechanisms, and we draw on characterisation data (SEM, TEM, EDS, XRD, FTIR) to show what the materials actually are. In the six primary studies examined closely, only one used real water, none reported ecotoxicity, one measured metal leaching, and regeneration was followed for five cycles at most. We propose a sensor-guided, recoverable workflow and minimum reporting standards. Magnetic nanomaterials look most credible as application-specific, recoverable components; sustainability claims need direct evidence.

Abstract as supplied by the indexing source. © the authors / publisher.