Nataša Tot

The optimization of BiVO₄-based structures significantly contributes to the development of a global system towards clean, renewable, and sustainable energies. Enhanced photocatalytic performance has been reported for numerous doped BiVO₄ materials. Bi³⁺-based compounds can be easily doped with rare earth (RE³⁺) ions due to their equal valence and similar ionic radius. This means that RE³⁺ ions could be regarded as active co-catalysts and dopants to enhance the photocatalytic activity of BiVO₄. In this study, a simple microwave-assisted approach was used for preparing nanostructured Bi_1−xEu_xVO₄ (x = 0, 0.03, 0.06, 0.09, and 0.12) samples. Microwave heating at 170 °C yields a bright yellow powder after 10 min of radiation. The materials are characterized through X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible–near-infrared diffuse reflectance spectroscopy (UV-Vis-NIR DRS), photoluminescence spectroscopy (PL), and micro-Raman techniques. The effects of the different Eu³⁺ ion concentrations incorporated into the BiVO₄ matrix on the formation of the monoclinic scheelite (ms-) or tetragonal zircon-type (tz-) BiVO₄ structure, on the photoluminescent intensity, on the decay dynamics of europium emission, and on photocatalytic efficiency in the degradation of Rhodamine B (RhB) were studied in detail. Additionally, microwave chemistry proved to be beneficial in the synthesis of the tz-BiVO₄ nanostructure and Eu³⁺ ion doping, leading to an enhanced luminescent and photocatalytic performance.

The optimization of BiVO₄-based structures significantly contributes to the development of a global system towards clean, renewable, and sustainable energies. Enhanced photocatalytic performance has been reported for numerous doped BiVO₄ materials. Bi³⁺-based compounds can be easily doped with rare earth (RE³⁺) ions due to their equal valence and similar ionic radius. This means that RE³⁺ ions could be regarded as active co-catalysts and dopants to enhance the photocatalytic activity of BiVO₄. In this study, a simple microwave-assisted approach was used for preparing nanostructured Bi_1-xEu_xVO₄ (x = 0, 0.03, 0.06, 0.09, and 0.12) samples. The materials are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible-near infrared diffuse reflectance spectroscopy (UV-Vis-NIR DRS), photoluminescence spectroscopy (PL), and micro-Raman techniques. Effects of the different Eu³⁺ ion concentrations incorporated into the BiVO₄ matrix on the formation of the monoclinic scheelite or tetragonal zircon-type BiVO₄ structure, on the photoluminescent intensity, on the decay dynamics of europium emission, and photocatalytic efficiency in degradation of Rhodamine B, were studied in detail.

This work reports the rapid aqueous microwave-assisted synthesis of monoclinic scheelite BiVO₄ nanoparticles and their behavior under visible light. X-ray diffraction (XRD) confirms phase-pure BiVO₄ with an average crystallite size of ~19 nm, consistent with transmission electron microscopy (TEM) observations, while N₂ sorption yields a BET surface area of 7.5 m²/g. UV–Vis diffuse reflectance spectroscopy (DRS) indicates a direct band gap of 2.55 eV. We evaluated the effects of catalyst dosage and initial Acid Orange 7 (AO7) concentration on visible-light degradation efficiency. Up to 77% removal was achieved within 120 min, with kinetics following a pseudo-first-order model (R² ≈ 0.970–0.996). Under the tested conditions, BiVO₄ also exhibited a modest antibacterial effect against Escherichia coli (~0.5 log reduction). These findings demonstrate that microwave-synthesized BiVO₄ is a multifunctional material and provides a quantitative baseline for practical wastewater treatment studies under visible light.

This work presents the synthesis, characterization, and multifunctional properties of bismuth vanadate (BiVO₄) nanoparticles prepared by a rapid and eco-friendly microwave-assisted method. X-ray diffraction (XRD) confirmed the formation of monoclinic scheelite-type BiVO₄ with an average crystallite size of ~19 nm. Transmission electron microscopy (TEM) revealed nearly uniform nanoscale morphology, while Fourier-transform infrared spectroscopy (FTIR) verified the presence of characteristic Bi–O and V–O vibrational modes. Nitrogen adsorption–desorption analysis (BET) indicated a specific surface area of 7.5 m²/g, consistent with a non-porous or weakly porous material. UV–Vis diffuse reflectance spectroscopy (DRS) determined a band gap of 2.55 eV, confirming visible-light activity. Photocatalytic performance was evaluated through the degradation of Acid Orange 7 (AO7) under visible-light irradiation. Effects of catalyst dosage and the initial concentration of pollutant Acid Orange 7 on photocatalytic degradation efficiency, were explained in details. Catalyst loading and initial dye concentration strongly influenced efficiency, achieving up to 77% removal within 120 minutes and well fitting to pseudo-first-order kinetics. In addition, the BiVO₄ nanoparticles exhibited notable antibacterial activity against Escherichia coli, attributed to synergistic effects of reactive oxygen species generation and direct surface interactions with bacterial membranes. These findings demonstrate that microwave-synthesized BiVO₄ is a multifunctional material with strong potential for integrated wastewater purification and disinfection applications.

The increasing volume of waste, particularly paper, plastics and metals, necessitates innovative technological solutions for efficient sorting and recycling. Conventional waste management systems rely on manual separation and inefficient processes, leading to resource loss and environmental pollution. This study explores the integration of advanced sensor technologies to enhance waste classification and optimize material recovery. Optical sensors, spectrophotometry, and hyperspectral imaging enable precise material identification based on optical properties, improving sorting accuracy and reducing contamination. Inductive and electromagnetic sensors enhance metal detection, while ultrasonic sensors facilitate material classification by density and structure. The implementation of these sensor-based automation systems significantly increases recycling efficiency, reduces landfill dependency, and promotes resource circularity. By leveraging advanced sensor technologies, this approach supports circular economy principles, minimizes environmental impact, and contributes to the development of smart and sustainable urban waste management systems.