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The current study proposed a novel simple and environmentally friendly approach for producing silver nanoparticles (AgNPs) using an extract of Moringa oleifera leaves (MOL) and optimizing the different experimental factors required for the formation and stability of AgNPs. The formation of nanoparticles was confirmed by a color change from yellow to reddish-brown with a surface plasmon resonance band at 412 nm. The morphology, size, and elemental composition of AgNPs were investigated by zeta potential dynamic light scattering, field emission scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, and transmission electron microscopy analysis, which showed crystalline and spherical AgNPs. The identification of functional groups was supported by Fourier-transform infrared spectroscopy. The photocatalytic activities of AgNPs were assessed in the degradation of organic Malachite green (MG) dye in the aqueous solution. Two kinetic adsorption models, the pseudo-first-order model and the pseudo-second-order model, and three isotherm models, the Langmuir, Freundlich, and Temkin, were used to mathematically characterize the MG degradation process. The pseudo-second-order kinetics and the Freundlich isotherm model were found to be in good agreement with the experimental data. As a result of their synergistic interaction with the MOL extract solution, the photocatalytic activity of AgNPs increases and they can successfully adapt to the photodegradation of organic dyes in industrial effluents.

The performance and response characteristics of simulated optical biosensor have been greatly enhanced in this work. The results were obtained by evaluating three different structures, each varying in the number of holes surrounding the cavity. The guidecavity coupling’s structural and dimensional characteristics were varied for an effective comparative study. The high sensitivity quality of this optical biosensor was achieved using large transmission rate. The results showed sensitivity around 800 nm/RIU in the first version, 800 nm/RIU in the second version, and 700 nm/RIU in the last version. Furthermore, the design parameters were optimized by finite difference time domain (FDTD) method. [ABSTRACT FROM AUTHOR]

Dyes are responsible for major environmental issues globally due to their toxicity, large-scale production, and extensive use in various industrial sectors. Pollution caused by hazardous dyes is mainly due to textile waste, which is constantly discharged into the aquatic system, often causing harm to humans and affecting water quality. In recent years, the removal of dyes from industrial textile wastewater has been a major challenge. Numerous technologies and methods have been developed to remove dyes from wastewater and meet clean water requirements. In this study, the effectiveness of activated carbon prepared by chemical activation of jujube stones for textile wastewater treatment was investigated. The effects of the concentration of H3PO4 and the carbonization temperature on the activated carbon's properties were studied. Several physicochemical methods, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction, methylene blue index, Boehm titration, iodine index and pH point of zero charge, were considered to characterize the produced adsorbents. To assess the quality of the two studied textile effluents (Mustard and Violet), the following parameters were used: biological oxygen demand (BOD), chemical oxygen demand (COD), turbidity, suspended particles and dissolved solids, before and after treatment with the produced activated carbon. Untreated wastewater analysis revealed high values for almost all parameters: pH > 9, COD of 302.72 mg/L and 230.68 mg/L for Mustard and Violet effluent, respectively. Both effluents from an industrial textile factory exhibited a COD/BOD ratio higher than three, which restricts their biodegradability. Examination of the effect of contact time and activated carbon dosage on the treatment of the two effluents showed that 4 g/L of activated carbon and 60 min of contact time were sufficient for optimal treatment, resulting in pollutant removal rates of 81.03 and 84.65% for the Violet and Mustard effluents, respectively. The results of this research highlight the efficiency of activated carbon derived from jujube stones as a cost-effective adsorbent for the treatment of real textile wastewater. [ABSTRACT FROM AUTHOR]

Lead ions are an efficient neurotoxic metal that results in serious disorders for human beings, including poisoning, kidney and liver disorders, hepatitis, anaemia, encephalopathy, and nephritic syndrome. The low-cost and eco-friendly biocomposite from Zea mays sponge (ZMS) biomass encapsulated using Na-alginate in the cross-linked matrix (ZMS/Na-alginate) as a biosorbent. A statistical approach uses full factorial design space to optimize the best conditions for preparation beads. The effect of concentrations (w/v, g/100 mL) of Na-alginate (X1), ZMS biomass (X2), and CaCl2 cross-linker (X3) retesting for Pb(II) ions elimination from the aquatic medium in batch mode. The supreme values optimized for X1, X2, and X3 are relevant to 4.5%, 2.5%, and 1.97%. After optimization using response surface methodology, the maximum lead removal by ZMS/Na-alginate biocomposite was 97.11%. The ZMS/Na-alginate biocomposite was characterized using scanning electron microscopy and attenuated total reflection spectroscopy to investigate physical and chemical modification in the structure during the biosorption system. Therefore, the synthesized ZMS/Na-alginate beads show considerable stability during 5 consecutive adsorption–desorption cycles. This approach study demonstrates that the optimized condition affects the removal of lead ions. The findings support using the modified raw biomass as a potential absorbent for heavy metal ions removal from aqueous media. [ABSTRACT FROM AUTHOR]

In this work, the microstructural and mechanical properties of treated Ti-6Al-4V alloy were investigated. Ekabor II boriding first treatment was carried out in this alloy for the formation of boride layers, and then a powder technique treatment with niobium was realized as a second treatment to form niobized layers. Scanning Electron Microscopy, Optical Microscopy, and X-ray diffraction were used to observe the obtained microstructures. It revealed that titanium alloy treated is composed of a" lamellar and ß phase stabilized by niobium. Besides, the microstructure of Ti-6Al-4V alloy is composed of a + ß phases. The microstructure contained two layers, which are differed in phase composition. The outer layer contained niobium (Ti-Nb), while the inner layer contained a mixture of titanium borides (TiB2 and TiB). The presence of niobium caused an increase in the micro hardness of the outer layer in comparison to the sample without niobium. The average values of indentation Vickers hardness (HV) obtained were equal to 1728 ± 50. Niobium presence has remarkable influence on the mechanical properties of inner layer of titanium borides (TiB2 and TiB). Moreover, the fracture toughness of the phase composition of the treated area was investigated. [ABSTRACT FROM AUTHOR]

Bacterial resistance to different antimicrobial agents is growing with alarming speed, especially when bacterial cells are living in biofilm. Hybrid nanoparticles, synthesized through the green method, hold promise as a potential solution to this challenge. In this study, 66 actinomycete strains were isolated from three distinct marine sources: marine sediment, the algae Codium bursa, and the marine sponge Chondrosia reniformis. From the entirety of the isolated strains, one strain, S26, identified as Saccharopolyspora erythrea, was selected based on its taxonomic position and significant antimicrobial activity. Using the biomass of the selected marine Actinobacteria, the green synthesis of eco-friendly silver carbonate nanoparticles (BioAg2CO3NPs) is reported for the first time in this pioneering study. The BioAg2CO3NPs were characterized using different spectroscopic and microscopic analyses; the synthesized BioAg2CO3NPs primarily exhibit a triangular shape, with an approximate size of 100 nm. Biological activity evaluation indicated that the BioAg2CO3NPs exhibited good antimicrobial activity against all tested microorganisms and were able to remove 58% of the biofilm formed by the Klebsiella pneumoniae kp6 strain.

Traditional chemical synthesis, which involves the use of dangerous protocols, hazardous solvents, and toxic products and catalysts, is considered environmentally inappropriate and harmful to human health. Bearing in mind its numerous drawbacks, it has become crucial to substitute conventional chemistry with green chemistry which is safer, more ecofriendly and more effective in terms of time and selectivity. Elaborating synthetic protocols producing interesting new compounds using both microwave heating and heterogeneous non-toxic catalysts is acknowledged as a green approach that avoids many classical chemistry-related problems. In the current study, β-enaminones were used as precursors to the synthesis of modified 4-hydroxy-2-quinolone analogues. The synthesis was monitored in a benign way under microwave irradiation and was catalyzed by bismuth chloride III in an amount of 20 mol%. This method is privileged by using a non-corrosive, non-toxic, low-cost and available bismuth Lewis acid catalyst that has made it more respectful to the demands of green chemistry. The synthesized compounds were obtained in moderate to good yields (51-71%) and were characterized by 1 H, 13 C NMR, and IR spectroscopy as well as elemental analysis. Compound 5i was subjected to a complete structural elucidation using the X-ray diffraction method, and the results show the obtention of the enolic tautomeric form., Competing Interests: The authors declare that they have no competing interests., (This journal is © The Royal Society of Chemistry.)