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The rapid discharge of antibiotic pollutants from pharmaceutical industries into natural water sources poses a significant threat to human health and the environment. Conventional water treatment methods often fail to effectively remove these contaminants, leading to a pressing need for eco-friendly degradation approaches. This study focused on synthesizing pure and iron-doped zinc sulfide (ZnS) nanoparticles using a microwave-assisted technique in aqueous solution to evaluate their photocatalytic efficiency in degrading the antibiotic cephalexin. High-resolution transmission electron microscopy (TEM) characterized the synthesized nanoparticles, revealing crystalline structures approximately 5 nm in size. The photocatalytic capacity was assessed using a spectrophotometric method, demonstrating that both pure and iron-doped ZnS nanostructures exhibit higher efficiency in degrading cephalexin under UV irradiation. These findings underscore the potential of ZnS nanostructures for photocatalytic applications in environmental remediation, particularly in degrading resistant antibiotic pollutants, highlighting their role in addressing organic pollution in water sources. 

The use of semiconductor materials, specifically TiO2, for photocatalysis of organic pollutants has gained global interest as an effective method for contaminant removal from wastewater. Titanium dioxide (TiO2) is a widely studied photocatalyst and is considered one of the best for wastewater treatments due to its high stability, affordability, and nontoxicity. The discharge of wastewater from the textile industries, which constitutes around 20% of total textile effluent, has become a significant environmental concern, posing a threat to both the aquatic ecosystem and human health. We aimed to investigate the photodegradation of organic dyes like Amaranth (AM), Methyl Orange (MO), and Quinoline Yellow (QY), individually and in combination, in an aqueous suspension with varying concentrations of TiO2. Results indicate a significant degradation of all three dyes in the multicomponent, with approximately 40% degradation in the presence of the 0.050 g/L TiO2 after 360 min. These findings suggest that TiO2 has a significant potential as a nanocatalyst in complex matrices. 

Semiconductor Zn-based nanomaterials have emerged as promising agents for the photocatalytic degradation of organic pollutants in wastewater treatment. However, achieving efficient synthesis protocols capable of rapidly producing small structures directly in aqueous environments remains challenging. Microwave-assisted synthesis presents a viable solution by enabling one-step particle generation swiftly and directly in water through increased pressure, thereby easily elevating the boiling point. This study investigates the microwave-assisted one-step synthesis of pure and iron-doped ZnS nanoparticles and assesses their efficacy in photodegrading Quinoline Yellow (QY) in aqueous suspensions. The results demonstrate a significant degradation of QY in the presence of 1% iron-doped ZnS nanoparticles, achieving approximately 66.3% degradation with 500 ppm of doped nanoparticles after 270 min. These findings highlight the considerable potential of 1% iron-doped ZnS nanoparticles as effective nanocatalysts. 

Magnesium oxide (MgO) nanoparticles (NPs) have gathered significant attention in recent years due to their promising antimicrobial properties and potential applications in various fields. These nanoparticles exhibit unique physicochemical characteristics, including a high surface area-to-volume ratio and exceptional stability. These attributes enable MgO nanoparticles to interact effectively with microorganisms, making them potent agents against a wide range of bacteria, fungi, and even some viruses. The antimicrobial activity of MgO nanoparticles is primarily attributed to their ability to produce reactive oxygen species (ROS) upon contact with moisture or biological fluids. These ROS, such as superoxide ions and hydroxyl radicals, inflict oxidative stress on microbial cells, leading to membrane damage, protein denaturation, and DNA disruption. Furthermore, MgO nanoparticles have shown low toxicity towards mammalian cells, making them attractive candidates for biomedical applications, including wound healing, drug delivery systems, and surface coatings for medical devices. The crystal size of MgO nanoparticles plays a crucial role in their antimicrobial properties, as smaller particles tend to exhibit enhanced antimicrobial activity due to their larger surface area, which facilitates greater interaction with microorganisms. Overall, MgO nanoparticles possess immense potential as antimicrobial agents, offering a novel approach against microbial infections. Based on the above, the present paper describes the development of a reproducible and cost-effective size-controlled synthesis route for nanoscale MgO as a function of crystal size. Nanoscale MgO was produced through the thermal decomposition of Mg-carbonate hydrate precursor (hydromagnesite) synthesized in aqueous phase and 80:20 ethanol:water mixture. The formation of the MgO phase, with an average crystallite size between 14.7 and 25.9 nm, was evidenced by X-Ray Diffraction (XRD), Infrared Spectroscopy (FT-IR), and Transmission Electron Microscopy (TEM) analyses. Thermogravimetric analyses were used to monitoring the weight loss percentage and the evolution from the precursor to the desired structure. 

Abstract The actual incorporation of dopant species into the ZnS Quantum Dots (QDs) host lattice will induce structural defects evidenced by a red shift in the corresponding exciton. The doping should create new intermediate energetic levels between the valence and conduction bands of the ZnS and affect the electron-hole recombination. These trap states would favour the energy transfer processes involved with the generation of cytotoxic radicals, so-called Reactive Oxygen Species, opening the possibility to apply these nanomaterials in cancer research. Any synthesis approach should consider the direct formation of the QDs in biocompatible medium. Accordingly, the present work addresses the microwave-assisted aqueous synthesis of pure and doped ZnS QDs. As-synthesized quantum dots were fully characterized on a structural, morphological and optical viewpoint. UV-Vis analyzes evidenced the excitonic peaks at approximately 310 nm, 314 nm and 315 nm for ZnS, Cu-ZnS and Mn-ZnS, respectively, Cu/Zn and Mn/Zn molar ratio was 0.05%. This indicates the actual incorporation of the dopant species into the host lattice. In addition, the Photoluminescence spectrum of non-doped ZnS nanoparticles showed a high emission peak that was red shifted when Mn 2+ or Cu 2+ were added during the synthesis process. The main emission peak of non-doped ZnS, Cu-doped ZnS and Mn-doped ZnS were observed at 438 nm, 487 nm and 521 nm, respectively. Forthcoming work will address the capacity of pure and Cu-, Mn-ZnS quantum dots to generate cytotoxic Reactive Oxygen Species for cancer treatment applications. 

ABSTRACT This work presents the synthesis of selenium-based nanoparticles via microwave-assisted heating and their subsequent characterization using UV-vis Spectroscopy (UV-Vis), high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray spectroscopy (EDX), techniques. Ongoing research includes the study of the nanoparticles capacity to generate reactive oxygen species (ROS).