Real-time Cr(VI) monitoring and remediation using Fe3O4 nanoparticles: Insights into Fe-Cr Spinels
Year: 2025
Type: article
Abstract: An analytical approach for the rapid and remote determination of Cr(VI) in water samples is demonstrated using Fe 3 O 4 nanoparticles and a cost-effective portable AC magnetometer. Cr(VI) reduction by surface Fe²⁺ leads to Fe/Cr precipitate formation, which alters the nanoparticles’ magnetic properties. Validation in natural water spiked with Cr(VI) showed a linear correlation between magnetic remanence and Cr(VI) concentrations from 0 to 10 mg/L, with a R 2 value of 0.99. Limitations of the method emerged at loadings above 10 mg/g, where extensive chromite (Cr x Fe 3-x O 4 ) coverage reduced the magnetic hysteresis area. Advanced characterization and DFT calculations revealed changes in spin-dependent properties, including magnetization reversal, electrical conductivity and magnetoresistance. This robust correlation between collective magnetic properties and Cr(VI) exposure enables, for the first time, milligram-per-liter detection via ultra-fast AC magnetometry, paving the way for real-time insight into redox processes in liquid environments and novel strategies for environmental remediation.
Institutions: Universitat Autònoma de Barcelona, Consejo Superior de Investigaciones Científicas, Institut de Ciència de Materials de Barcelona, Universidad Complutense de Madrid, Universidade de Santiago de Compostela, Aristotle University of Thessaloniki, Institut Català de Nanociència i Nanotecnologia, University of Catania, Institute for Microelectronics and Microsystems, Institució Catalana de Recerca i Estudis Avançats
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,350
OpenAlex ID: W4413371472