Environmentally benign fabrication of superparamagnetic and photoluminescent Ce,Tb-codoped Fe3O4-gluconate nanocrystals from low-quality iron ore intended for wastewater treatment

Abstract

At present, wastewater treatment is a fundamental ecological problem since contaminated organics, such as dyes, stand as a foremost and rising cause of water pollution. Accordingly, legislation directed toward ensuring the elimination of toxic dyes from wastewater is becoming ever more rigorous, making the progress of more effective nanomaterials for degrading toxic dyes a critical challenge for chemists. A capable technique to address this problem utilizes metal ion-doped semiconductors to catalytically photodegrade the stable bonds in these dye molecules. Despite extensive research in this area, the invention of an efficient doped semiconductor system remains a key challenge. Herein, we have advanced the previous study by designing a fluorescent-superparamagnetic-photocatalytic Ce,Tb-codoped Fe₃O₄ nanocrystals with an amorphous carbon coating via an unsophisticated single-pot D-glucose mediated hydrothermal reduction method using a single iron precursor (FeCl₃·6H₂O) obtained from gathered iron ore tailings- a mining waste that characteristically symbolizes a major environmental hazard. Such trifunctional nanocrystal formations were verified using X-ray diffraction (XRD), FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis, and transmission electron microscopy (TEM) imaging. XPS and XRD analyses confirmed the efficient doping of lanthanide ions into the Fe₃O₄ host lattice. Photoluminescence (PL) spectra showed that the doped nanocrystals with a precise dopant ratio displayed a strong cyan light emission. Furthermore, time-correlated single-photon counting (TCSPC) measurements indicated how the dopant percent variation in Fe₃O₄ influenced their corresponding average lifetime values. The magnetization measurements demonstrated the superparamagnetic behavior with variated magnetic saturation values, which were established to be dependent on the doping effect. Samples with an appropriate doping ratio were established to be more efficient for the photodecomposition of Rhodamine B under visible light irradiation with remarkable recyclability and structural stability. Such trifunctional nanocrystals may find many biomedical applications, such as cancer detection and drug delivery, and the technique we used can be extended to the synthesis of other nanomaterials based on lanthanide ion-doped materials and metal oxides.