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In this study the catalytic ability of green synthesized nickel oxide nanoparticles (NiO NPs) is investigated for degradation of methyl orange as a hazardous environmentally contamination in water. The NiO NPs was prepared at ambient conditions using the antioxidant content of Punica granatum L. (pomegranate) juice extract and their bio-reducing ability were studied in details. This process is entirely green process, free from toxic and hazardous solvent. The biosynthesized NiO NPs were in nano scale and their morphology, sizes, surface area and optical properties were characterized using field emission scanning electron microscope (FE-SEM), BET surface area analysis, thermogravimetric analysis, energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD) and ultraviolet–visible spectroscopy (UV–Vis). The biosynthesized NiO NPs were found to be active catalysts, particularly with the reducing agents for instance sodium borohydride, for the degradation of the toxic organic dyes such as methyl orange (MO) in contaminated water. The NiO NPs are stable and reusable for reducing MO to its leuco-form, in a short time, in an aqueous medium in the absence of reducing agents. This method is much cheaper than the other methods. The catalytic activity of NiO NPs can be explained by its small size, compared with the bulk materials, which produce numerous active sites due to its big surface area per unit volume.

The development of green-based nanomaterials as antimicrobial agents offers a sustainable and safe alternative to conventional antibiotics, aligning with both environmental and public health priorities. The paper wasp ( Parapolybia escalerae ) is a novel species known for its unique honey, which has not been previously explored for its potential in green nanotechnology and biomedical applications. In this study, paper wasp honey was used to prepare silver nanoparticles (H-Ag NPs), which serves a dual role as both the reducing and stabilizing agent. The structural, morphological, and optical characteristics of the biosynthesized nanoparticles were assessed using UV-Vis double beam spectroscopy, X-ray diffraction (XRD) pattern, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). Additionally, the antibacterial potential of the synthesized H-Ag NPs was evaluated against gram-positive bacteria Staphylococcus aureus (ATCC 6538), Staphylococcus aureus MRSA, and multidrug-resistant gram-negative bacteria Acinetobacter baumannii by determining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth microdilution method. Notably, MIC and MBC of this nanoparticle against S. aureus (ATCC 6538) and S. aureus MRSA strains were found to be 17.5 µg/mL. Additionally, at lesser doses (8.5 µg/mL), these nanoparticles can inhibit the growth of the Gram-negative bacteria A. baumannii . The novel feature of this method lies in its environmentally friendly and sustainable approach, as it avoids the use of hazardous chemicals typically employed in conventional synthesis methods.

This research introduces a pioneering green method for synthesizing zinc oxide nanorods (ZnO NRs) on a glass substrate using Thymus kotschyanus plant extract. The study delves into the intricate effects of ammonium hydroxide and precursor concentrations on the morphology, size, alignment, and crystalline structure of ZnO NRs. Through systematic experimentation, it was found that specific concentrations of these substances play vital roles in the formation and properties of the nanorods. Notably, a low concentration of the precursor coupled with a high concentration of ammonium hydroxide led to well-aligned hexagonal ZnO NRs with a remarkable aspect ratio. Variations in these concentrations were also found to influence the length, diameter, and alignment of the nanorods. The findings were corroborated using a diverse array of analytical techniques, including transmission and scanning electron microscopy, x-ray diffraction, UV–vis spectroscopy, and energy-dispersive x-ray analysis. The UV–vis spectra provided further insights into the optical properties and band gap energy of the ZnO NPs, while EDX analysis confirmed the elemental composition. This work represents a significant advancement in eco-friendly nanomaterial synthesis, providing detailed insights into the controlled fabrication of aligned ZnO NRs. Its innovative approach and extensive investigation into influencing factors make it a valuable contribution to the field of nanoscience.

This study explores the optical properties of polyethylene oxide (PEO) modified with natural dye extracted from hollyhock (HH) flowers. This study is a green chemistry approach to reduce the optical band gap of PEO polymer. The UV-vis analysis of the HH dye demonstrated absorption spanning from UV to visible regions of the electromagnetic spectrum. Fourier transform infrared spectroscopy (FTIR) analysis identified significant transmittance bands linked to the OH, NH, and C = O functional groups of HH dye. The shifts and intensity changes in FTIR bands of the doped PEO indicate interactions between PEO and HH dye functional groups. A shift was observed in the absorption edge from 5.6 eV for clean PEO to 2.6 eV for dye-doped film. The addition of HH dye resulted in an increase in the optical dielectric constant, suggesting a rise in the localized density of energy states within the forbidden band separating the valence bands (VBs) and conduction bands (CBs). The refractive index of doped PEO was found to be 1.73 which is greater than that of pure PEO (1.27). The optical band gap determination based on Tauc’s model was found to decrease from 5.3 eV for pure PEO to 2.4 eV for dye-doped PEO film. The study identified the dominant type of electron transition, a complex topic in condensed matter physics involving electrons crossing the band gap.

Concrete is a composite material widely used in construction. Waste slag smelting (pyrometallurgical) (steel slag (SS)) is a molten liquid melt of silicates and oxides created as a by-product of steel production. It is a complex solution of silicates and oxides. Steel slag recovery conserves natural resources and frees up landfill space. Steel slag has been used in concrete to replace fine and coarse particles (gravel). Three hundred thirty-eight data points were collected, analyzed, and modeled. It was determined which factors influenced the compressive strength of concrete with steel slag replacement in the modeling phase. Water/cement ratio was 0.3–0.872, steel slag content 0–1196 kg/m 3 , fine aggregate content 175.5–1285 kg/m 3 , and coarse aggregate content (natural aggregate) 0–1253.75 kg/m 3 . In addition, 134 data were collected regarding the electrical conductivity of concrete to analyze and model the effect of SS on electrical conductivity. The correlation between compressive strength and electrical conductivity was also observed. This research used a linear regression (LR) model, a nonlinear regression (NLR) model, an artificial neural network (ANN), a full quadratic model (FQ), and an M5P tree model to anticipate the compressive strength of normal strength concrete with steel slag aggregate substitution. For predicting the electrical conductivity, the ANN model was performed. The compressive strength of the steel slag was raised based on data from the literature. Statistical techniques like the dispersion index and Taylor diagram showed that the ANN model with the lowest RMSE predicted compressive strength better than the other models.

Zinc oxide (ZnO) nanorods have been extensively investigated, owing to their extraordinary applications in numerous fields, spatially microchip technology, solar cells, sensors, photodetectors, photocatalysts and many others. Recently, using ZnO nanorods, as photocatalysts, are receiving increasing attention in environmental defense applications. This mini review summarizes some remarkable applications for ZnO nanorods. First, the various chemical and physical procedures that were used to produce ZnO nanorods are identified through symmetric matrices and heterogeneous structures, then the authors explain how to use these methods to produce ZnO nanorods. This mini review, also, discusses the applications of ZnO nanorods in many fields, especially in field release, emission properties, and electron transference. Last but not least, the appropriate conclusions for future research using ZnO nanorods have been successfully explained.

ZnO nanorods were synthesized via CBD method on a seed layer coated substrate. Prior to growth, a glass substrate was seeded with the biosynthesized ZnO nanoparticles using Thymus Kotschyanus extract. XRD confirmed that for the sample within higher precursor concentration, the (100) peak is noticeably shorter, and the majority of the nanorods are grown in the (002) plane, indicating crystal growth are along the c-axis. However, the nanorods are mostly aligned along the (100), (002), and (101) planes for samples at 0.02 and 0.05 Mol precursor concentrations. The presence of ZnO nanorods within hexagonal-wurtzite structure, is favored orientation along the c-axis. As the precursor concentrations of the seed layer increased from 0.02 to 0.1 Mol, the dispersion of ZnO nanoparticles became denser, the maximum absorption peaks red-shifted, from 395 to 420 nm, and the bandgap energy of the biosynthesized ZnO decreased from 3.59 to 3.38 eV, with increasing precursor concentrations. Graphical abstract

This study aims to investigate the effect of waste steel slag (SS) as partially replaced with cement and fine aggregate on concrete for different mixes in terms of compressive strength (CS) and electrical resistivity (ER). SS is a molten mixture of silicates and oxides that solidifies upon cooling, a byproduct of the steel-making process. Before conducting the design experiments, the optimal percentage of SS in both powder and fine aggregate forms was established through seven different mixes. This aimed to examine the influence of various SS particle sizes on CS. Based on the results achieved, the optimum percentage and effective size of SS were selected to modify and investigate the effect of SS on three different mixes of conventional concrete (M25, M35, and M47) in terms of CS, ER, and concrete slump. The resistivity of each mixture was assessed by implementing four-probe (4P) and two-probe (2P) techniques, ranging from the initial stages of curing up until the 28 days of the curing. The exclusion of the wire probe in the 4P technique is evidenced by the findings, which indicate that 4P is superior to 2P in terms of ER detection accuracy. Computing the correlation between the 2P and 4P approaches is crucial to obtain the correct resistivity value. The concrete slump value and initial resistivity ( ρ o ) correlation model was developed. The results demonstrated that the concrete slump could be determined based on concrete with high accuracy, with the coefficient of determination ( R 2 ) 0.8 and 0.84 for 2P and 4P, respectively. Moreover, the findings also indicated that the CS of M25 concrete, when enhanced with SS, was 2.27% lower than that of M25 concrete without SS after 28 days of curing. In contrast, the CS of M35 concrete with SS modification was 6.74% higher than that of the unmodified M35 concrete. Similarly, for M47 concrete modified with SS, its CS was 12.8% greater than the original M47 concrete.

Concrete is a very flexible composite material that is extensively employed in the building industry. Steel slag is a waste material produced during steelmaking. It is formed during the separation of molten steel from impurities in steelmaking furnaces. Slag starts as a molten liquid melt and cools to a solid state. It is a solution of silicates and oxides that is rather complicated. Steel slag recovery is environmentally friendly since it conserves natural resources and frees up landfill space. Steel slag has been extensively utilized in concrete as a partial substitute for normal and crushed coarse aggregate to improve the mechanical qualities of normal-strength concrete, such as compressive strength. The researchers and suppliers investigated that using steel slag instead of normal coarse aggregate could save the environment and natural resources. Three hundred thirty-eight (338) data sets were gathered and evaluated in total. During the modeling procedure, the most significant factors affecting the compressive strength of concrete with steel slag replacement were considered, including the curing time of 1–180 days, the cement content of 237.35–550 kg/m 3 , the water-to-cement ratio of 0.3–0.872, the fine aggregate content of 175.5–1285 kg/m 3 , the steel slag content of 0–1196 kg/m 3 , and the coarse aggregate content of 0–1253.75 kg/m 3 . A credible mathematical model is needed to investigate the influence of steel slag as a partial replacement on concrete compressive strength. Mathematical models will help engineers and concrete industries mix a proper concrete mix design, including steel slag, to achieve a desired compressive strength without doing any experimental work. As a result, an artificial neural network (ANN), an adaptive network-based fuzzy inference system (ANFIS), a multivariate adaptive regression splines (MARS), and an M5P-tree model were presented in this research to predict the compressive strength of concrete with steel slag aggregate replacement. According to previous research findings, all percentages of steel slag improve compressive strength. According to statistical studies, the adaptive network-based fuzzy inference system model outperformed the other models in forecasting steel slag replacement compressive strength for normal strength concrete (ANN, MARS, and M5P-tree). It has a higher coefficient of determination of 0.99, a smaller mean absolute error of 0.74 MPa, a smaller root mean square error of 1.12 MPa, a smaller scatter index of 0.029, and a smaller objective of 0.93 MPa.