Ultraviolet Spectroscopy Research Articles

Green synthesis of gold nanoparticles using Pelargonium Graveolens leaf extract: characterization and anti-microbial properties (An in-vitro study)

Background In recent years, there has been a notable increase in the level of attention devoted to exploring capabilities of nanoparticles, specifically gold nanoparticles AuNPs, within context of modern times. AuNPs possess distinct biophysical properties, as a novel avenue as an antibacterial agent targeting Streptococcus Mutans and Candida Albicans. The aim of this study to create a nano-platform that has the potential to be environmentally sustainable, in addition to exhibiting exceptional antimicrobial properties against Streptococcus Mutans as well as Candida Albicans. Methods this study involved utilization of Pelargonium Graveolens leaves extract as a cost effective and environmentally sustainable approach for the green synthesis of AuNPs. Subsequently, physicochemical characteristics were assessed employing a variety of analytical methods, including as transmission electron microscopy, X-ray diffraction, Field Emission Scanning Electron Microscope, Zeta potential, Ultraviolet visible absorption spectroscopy, and Energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The antimicrobial efficacy against Streptococcus Mutans and Candida Albicans was evaluated. Nanoparticles of various shapes, including hexagonal, spherical, semi-spherical, and triangular, were synthesized. These nanoparticles exhibited a mean particle size of 294nm and demonstrated low degree of aggregation. These nanoparticles exhibited long-term stability and were capable of facilely combining with diverse bioactive compounds. Results The study demonstrated that AuNPs which is synthesized by green methods display potent antimicrobial properties. Conclusion Utilization of Pelargonium Graveolens AuNPs may exhibit a promising potential as an antibacterial agent against Streptococcus Mutans and Candida Albicans. Nanoparticles (NPs) have the potential to serve as a novel approach for addressing pathogen infections as well as for biomedical, dental and pharmaceutical purposes in the future.

Structural, spectroscopic, fluorescent, and computational studies of binuclear copper (II) and zinc (II) complexes with an asymmetric salamo‐type ligand

Salamo‐type ligand H2L was designed and synthesized and reacted with Cu (II) and Zn (II) acetate, respectively, to obtain two binuclear Cu (II) and Zn (II) complexes: [Cu2(L)2]·2CH3OH (1) and [Zn2(L)2] (2) having the same coordination number but distinct geometries. Complex 1 is a Cu (II) complex containing two crystalline ethanol molecules, where two Cu (II) atoms are surrounded by two utterly deprotonated (L)2− parts, forming slightly twisted tetragonal pyramidal configurations of pentacoordinate. In complex 2, two utterly deprotonated (L)2− parts surround two Zn (II) atoms, forming pentadentate twisted triangular bipyramidal configurations. The complexes were elucidated via IR analyses and ultraviolet spectroscopy. Using DFT theoretical calculation, MEPs, IRI, and Hirshfeld surface analysis to investigate further the molecular interactions and reaction sites. Ultimately, the fluorescence characteristics of H2L and its complexes 1 and 2 were discussed.

Development of a certified reference material for D-phenylalanine with evaluation of enantiomeric purity.

D-Phenylalanine (D-Phe) is a small chiral organic molecule that is both an important pharmaceutical intermediate and used as a calibrator for quantifying amino acids in liquid chromatography-circular dichroism. We have developed a process for a national certified reference material (CRM) for D-Phe following ISO 17034:2016. The identity of D-Phe was confirmed using mass spectrometry (MS) and nuclear magnetic resonance (NMR), infrared, and ultraviolet (UV) spectroscopy. The absolute optical conformation was also determined using circular dichroism (CD) spectroscopy and optical rotation measurements. Impurities were identified via liquid chromatography (LC) with a UV-Vis detector and a charged aerosol detector (CAD) and LC-MS. Both mass balance and quantitative NMR were employed for value assessment, and the associated uncertainty was evaluated. The certified purity was determined to be 0.995 ± 0.003g/g, a validation that was confirmed by CD using L-Phe CRM as a calibrator. Twenty milligrams of raw material was packed in sealed brown glass tubes for storage, and no inhomogeneity was observed. Stability tests revealed that the D-Phe CRM remained stable at -20°C for at least 26months, at 4°C for at least 14days, and at 25°C and 60°C for at least 7days. The D-Phe CRM can be used to ensure the accuracy and reliability of D-Phe quantitation in the pharmaceutical field and also as a calibrator to ensure traceability to the International System of Units (SI) for L-Phe quantitation and protein purity analysis using LC-CD methods. The approach outlined in this paper also has potential for use in the development of other chiral CRMs.

Fabrication of a Reversible Fluorescence Sensor Based on Nitrogen‐Sulfur Co‐Doped Multiwalled Carbon Nanotubes for Detection of Mercury Ions: Experimental and DFT Insights

AbstractAn eco‐friendly approach involving hydrothermal treatment followed by thermal annealing was adopted for the preparation of nitrogen‐sulfur co‐doped multi‐walled carbon nanotubes (NS‐CNT@600) using melamine and thiourea as precursors. The prepared NS‐CNT@600 were characterized using X‐Ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), X‐Ray Diffraction (XRD), High‐Resolution Transmission Electron Microscopy (HR‐TEM), Ultraviolet and Visible Spectroscopy (UV‐Vis). They were applied for the fluorescent detection of Hg2+ ions in water. A fluorescence quenching sensor for sensitive and precise detection of Hg2+ ions was developed by making use of the sensitivity of NS‐CNT@600 to fluorescence quenching behavior caused by interaction with Hg2+ ions. Additionally, the selectivity of NS‐CNT@600 towards Hg2+ ions was thoroughly investigated in the presence of other interfering metal ions. There was a linear relationship between fluorescence intensity and Hg2+ concentration from 10 to 50 nM with a limit of detection (LOD) of 6.3 nM. The proposed method was also tested on real water samples with positive results. Physicochemical features and interaction mechanism of analyte‐material transduction were exclusively studied by combining fluorescence spectrophotometry and density functional theory (DFT) calculation techniques. The strategy provides an easy way to develop low‐cost, selective and sensitive probes for rapid fluorescent sensing of Hg2+ ions in aqueous solutions.

Characterization of MoS2:Nb sputtered thin films. An application as hole transport layer in Cu2ZnSnS4/Si tandem solar cells

MoS2:Nb films deposited by radio-frequency magnetron sputtering are investigated in view of their application in infrared (IR)-transparent contacts for tandem photovoltaic devices.This material is already known to give a good electrical contact with p-type chalcogenide semiconductors, which are typically grown onto opaque molybdenum metallic contacts and a MoS2 layer spontaneously forms at the back interface during the on-top semiconductor growth. Our study explores a different approach, which involves the direct growth of IR-transparent MoS2:Nb films via sputtering inside complete photovoltaic devices, like Cu2ZnSnS4 (CZTS)-based single junction solar cells and CZTS/Si tandem devices. Films deposited at different sputtering pressures are compared by analysing their microstructure, morphology, chemical composition, optical and electrical properties. The effects of post-deposition sulfurization treatments are also investigated. We find that MoS2:Nb films deposited at around 0.1 Pa exhibit compactness but show a notable sulfur deficit ([S]/[Mo]≈1.4), a significant sub-bandgap optical absorptance and lack of crystallinity. Increasing the Ar pressure to 1 Pa raises the [S]/[Mo] ratio to 2.2, yielding crystalline films with good IR-transparency, although with a porous morphology. Despite 0.5 wt% Nb-doping of the sputtering target, the as-deposited films demonstrate n-type conductivity likely due to uncontrolled impurities and intrinsic defects. Ultraviolet Photoemission Spectroscopy measurements suggest that films’ work function higher than 5 eV can be obtained with a post-deposition sulfurization, making these materials suitable as Hole Transport Layer in photovoltaic applications. A similar increase in work function is expected in the CZTS/MoS2 junctions, since the sputtered MoS2:Nb films undergo a sulfurization process needed to obtain the overlying polycrystalline CZTS absorber.CZTS solar cells produced with sputtered MoS2 and Transparent Conductive Oxides contacts on glass substrates, despite plagued by severe adhesion problems, show the potentiality to give efficiencies comparable to reference devices with standard Mo back contact. Fabrication of CZTS/Si tandem devices on textured silicon bottom cells yields a maximum efficiency of 4.4 %, primarily hindered by the low quality of the CZTS film on textured substrates. Nonetheless, optoelectronic characterizations based on both spectrophotometric and quantum efficiency measurements confirm a good IR transparency of the MoS2-based intermediate contacts and the desired electrical behaviour.

Bioactive secondary metabolites from an endophytic fungus Aspergillus sp. CCH-1E from Catharanthus roseus

This study focused on the bioactive secondary metabolites of an endophytic fungus Aspergillus sp. CCH-1E from Catharanthus roseus. The secondary metabolites from Aspergillus sp. CCH-1E were isolated by using various chromatographic methods [such as normal-phase and reversed-phase chromatography and high-performance liquid chromatography(HPLC)], and their structures were identified by various spectroscopic methods [e.g., ultraviolet(UV) spectroscopy, infrared(IR) spectroscopy, nuclear magnetic resonance(NMR) spectroscopy, and high-resolution electrospray ionization mass spectrometry(HR-ESI-MS)]. Twelve compounds were yielded and identified from Aspergillus sp. CCH-1E, which are chermesinone H(1), chermesinone I(2), chermesinone B(3), 8,11-didehydrochermesinone B(4), chermesinone C(5), chermesinone A(6), chevalone B(7), barbacenic acid(8), 3,6,8-trihydroxy-3,5,7-trimethyl-3,4-dihydroisocoumarin(9), 5-hydroxy-2-methoxy-7-methyl-1,4-naphthoquinone(10), 1-hydroxy-6,8-dimethoxy-3-methylanthracene-9,10-dione(11), and 7-drimen-9α,11,12-triol(12). Among them, compounds 1 and 2 are new compounds. The growth inhibition effects of all compounds were evaluated against non-small cell lung cancer cell lines A549 and NCI-H1650, as well as human cervical cancer cell line HeLa by using methylthiazolyldiphenyl-tetrazolium bromide(MTT). Compound 7 significantly inhibited the growth of three tumor cells with the IC_(50) values of 1.22-2.43 μmol·L~(-1), respectively. Compounds 1-6 showed moderate cell growth inhibition with the IC_(50) values of 16.24-35.28 μmol·L~(-1).

Effects of rosmarinic acid covalent conjugation on the allergenicity and functional properties of egg white protein

Polyphenols can form complexes with proteins, potentially enhancing the properties of egg white protein (EWP) by altering its structure. This study aimed to explore the effect of covalent conjugating with rosmarinic acid (RA), a bioactive polyphenol found in various edible Lamiaceae herbs, on the structure, allergenicity, and functional properties of EWP. The successful preparation of EWP-RA conjugates was confirmed through RA binding equivalent analysis. Fluorescence spectroscopy, Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD), and ultraviolet (UV) absorption spectroscopy collectively indicated that the covalent conjugation with RA led to significant structural alterations in EWP. Furthermore, the conjugation of RA markedly enhanced the antioxidant capacity of EWP, as evidenced by its improved ability to scavenge DPPH and ABTS+ radicals. Enzyme-linked immunosorbent assay (ELISA) results indicated a substantial reduction in the binding capacity of EWP-RA conjugates to IgG and IgE, indicating a decrease in the allergenic potential of EWP. Moreover, the incorporation of RA was associated with an increase in the absolute zeta potential, protein flexibility, and free sulfhydryl content of EWP, alongside a reduction in surface hydrophobicity. The findings also revealed that RA enhanced the emulsifying activity, emulsion stability, foaming ability and foaming stability of EWP. Furthermore, the storage performance of EWP improved after conjugation with RA. In conclusion, the covalent conjugation of EWP with RA not only diminished its allergenic potential but also improved its functional properties through structural modification. This study posits that such an approach could be an effective strategy for enhancing the functional properties of EWP while concurrently mitigating its allergenic potential, thereby offering promising applications in the formulation of future food products.

Species discrimination of β-phenylethylamine, NaCl and NaOH based on Ultraviolet spectroscopy and principal component analysis combined with improved clustering by fast search and find of density peaks algorithm

This paper aimed at putting forward an approach integrating the improved clustering by fast search and find of density peaks (I-CFSFDP) algorithm with Ultraviolet (UV) spectroscopy for identifying the species of NaCl, NaOH, β-phenylethylamine(PEA) and their mixtures. For solving the issue that the clustering precision of the CFSFDP algorithm relies on the density forecast of the dataset and the manually selection of the truncated distance dc. The idea of kernel density forecast was adopted to the I-CFSFDP algorithm. The I-CFSFDP algorithm can observe the clusters of arbitrary shapes and use an adaptive method to evaluate the truncated distance dc, thereby generating more accurate clusters and identifying the core points in the clusters effectively. The dimensions of the UV spectra was reduced with principal component analysis (PCA), and the results of PCA were invoked as the input of the I-CFSFDP algorithm. Meanwhile, the effect of PCA-I-CFSFDP was evaluated by recall, accuracy, F-Score and precision. Besides, the DBSCAN and PCA-CFSFDP algorithms were used to compare with the PCA-I-CFSFDP algorithm. All of the classification outcomes displayed that the PCA-I-CFSFDP algorithm has better performance than the DBSCAN and PCA-CFSFDP algorithms. Therefore, the PCA-I-CFSFDP algorithm integrated with UV spectroscopy is a simple, quick and credible identification approach for detecting PEA, NaCl, NaOH and the mixtures.

Controllable preparation of YPrO3 photocatalystvia sol-gel method with enhanced photocatalytic performance under ultraviolet light

In this work, an ultraviolet light-driven YPrO3 photocatalyst was successfully synthesized via the sol-gel method, utilizing yttrium nitrate hexahydrate (Y(NO3)3·6H2O) and praseodymium nitrate hexahydrate (Pr(NO3)3·6H2O) as the yttrium and praseodymium sources, respectively, with oxalic acid dihydrate (H2C2O4·2H2O) serving as an auxiliary solvent. In addition, the prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy(XPS), thermogravimetric and differential scanning calorimetry (TG-DSC), ultraviolet visible diffuse reflectance spectroscopy (UV VisDRS), and an electrochemical workstation. Also, the photocatalytic activity of YPrO3 samples was explored by using methyl orange (MO) solutionas a model pollutant to simulate wastewater under varying synthesis temperatures and illumination durations. The material with the highest degradation efficiency was subjected to cycling and recovery experiments to assess its stability. Furthermore, the photocatalytic mechanism of YPrO3 was investigated. Experimental results revealed that pure YPrO3 samples could be effectively synthesized at calcination temperatures ranging from 850 °C to 1000 °C, with the sample prepared at 900 °C exhibiting the optimal photocatalytic activity. This sample possessed an average grain size of 4–5 μm. Under UV light irradiation for 90min, the YPrO3 sampleprepared at 900°Cachieved approximately 80 % degradation of methyl orange at an initial concentration of 5 mg/L. After five consecutive cycles, the degradation rate remained as high as 70.39 %, with no change in the crystal structure, indicating excellent stability. The photocatalytic mechanism of YPrO3 was found to involve the synergetic effect of superoxide radicals and photogenerated holes in degrading pollutants. In conclusion, YPrO3could be a promising photocatalyst with excellent performance, holding broad application prospects.

Aloe vera leaf (Aloe barbadensis) iron-oxide nanoparticles improved growth performance, immune response and survival of African sharptooth catfish (Clarias gariepinus) challenged with Aeromonas hydrophilia

ABSTRACT Nano-sized essential minerals and nutrients synthesized from plant extracts are being explored for their impact on growth, immune stimulation, and overall fish health. This study evaluated the growth performance, health, and survival of African catfish, Clarias gariepinus, particularly when challenged with Aeromonas hydrophila. Biosynthesized Aloe vera leaf iron oxide nanoparticles (ANP) were confirmed by ultra-violet spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscopy as nanoparticles. The ANPs were added to the basal diet at 0, 40, 80, 120, and 160 mg/kg, forming five treatments. The fish were fed to apparent satiation twice daily for 84 days. Results showed that dietary ANP improved weight gain, specific growth rate, protein efficiency ratio, and feed conversion ratio significantly with increasing levels of the nanoparticles. Fish fed 160 mg/kg ANP diet had a weight gain of 102.12 ± 18.91 g, while fish fed the control diet had a weight gain of 78.89 ± 22.2 g. Fish quality indices, including head-to-body percentage, visceral-somatic ratio, and flesh ratio, were similar (p > .05) across treatments. Supplementation of ANP improved significantly fish carcass quality and survival rate compared to the control diet. Fish fed nanoparticle diets had significantly different (p < .05) moisture, ash, and protein contents across all treatments. The fat content decreased with increasing nanoparticle levels, with the control diet showing the highest value (14.54%) and 160 mg/kg ANP diet the lowest (12.94%). Dietary ANP also improved carcass iron and zinc contents significantly. Additionally, ANP increased packed cell volume, red blood cells, white blood cells, hemoglobin, and erythrocyte sedimentation count more than the control diet. Alanine transferase, aspartate transferase, catalase, and superoxide dismutase levels increased with ANP in the diets. Fish-fed ANP diets had higher (p < .05) total serum protein than fish fed the control diet. ANP diets reduced blood glucose levels significantly, and cholesterol levels decreased marginally with increasing nanoparticle levels. Conclusively, ANP positively influenced the growth, immunity, and survival of C. gariepinus.

Ultraviolet visible spectral water chemical oxygen demand detection method based on two deep neural network model

Water resources are precious resources around the world, but pollution is becoming increasingly severe. While the degree of damage to water caused by organic pollutants is reflected by chemical oxygen demand, which is also an important indicator for hydrological monitoring. Therefore, accurate measurement of chemical oxygen demand is necessary. The rapid development of water quality detection by ultraviolet visible spectrum analysis as an efficient, convenient, and pollution-free new water quality detection method has been achieved. When we were processing ultraviolet visible spectral absorbance data, various environmental factors can affect the chemical oxygen demand light absorption value, thus affecting the accuracy of detection. So there are some goals, such as more comprehensively extracting the feature wavelength and reducing the interference to achieve better detection results. It is expected that the model can be applied to a portable water quality detection device. It is necessary to consider detection time, reduce model training parameters, and improve detection speed. Therefore, this article proposes Competitive Adaptive Weighted Sampling-Convolutional Neural Network-Long Short-Term Memory and Competitive Adaptive Weighted Sampling-Convolutional Long Short-Term Memory models for detecting chemical oxygen demand in water. To verify the effectiveness of the proposed model, the model was trained on the experimental dataset and the detection results of all models involved in the article were compared. It can be confirmed that the application of these two proposed algorithms results in less detection time and higher accuracy in concentration detection.

The dynamics and transport of ozone in the gas and liquid phase generated by air surface microdischarge plasma at atmospheric pressure

AbstractThis contribution focuses on the spatial‐temporal behavior and reactive pathways of O3 produced by a surface air microdischarge in the gas and liquid phase using ultraviolet absorption spectroscopy. The findings demonstrate that mode transition from ozone to nitrogen oxide over time is observed at a constant input power higher than ~0.60 W/cm2. Due to the long‐lived characteristic and ionic wind, the perpendicular distribution of O3 is almost uniform. The maximum penetration depth is around 5 mm, and the gas–liquid mass transfer efficiency is approximately 0.4‱ at a depth of 1 mm, when the treatment time is 10 min. The mass transfer of O3 between gas and liquid phases is dominated by the liquid convention induced by ionic wind.

The interaction between resveratrol and catalase was studied by multispectral method and molecular docking simulation

In this research, we delved into the interaction mechanism between Resveratrol (RES) and Catalase (CAT) utilizing a suite of advanced analytical techniques, including multispectral analysis and molecular docking simulation. A comprehensive assessment of their binding characteristics, modalities, distances, and the subsequent impact on CAT's secondary structure was conducted through fluorescence spectroscopy, ultraviolet spectroscopy, circular dichroism, three-dimensional fluorescence spectroscopy, synchronous fluorescence spectroscopy, and molecular docking simulation. By employing the Stern-Volmer equation to determine KSV and Kq values, Our findings indicate that the RES-CAT interaction results in static fluorescence quenching, By conducting experiments, the binding constant KA and the number of binding sites n for CAT and RES were determined, with the number of binding sites n being close to 1, indicating the presence of a specific binding site between CAT and RES. Parameters at 298 K. The negative values of ΔH and ΔS suggest that van der Waals forces and hydrogen bonding are predominant in mediating the interaction between CAT and RES. The negativity of ΔG indicates the spontaneity of the reaction. The Fӧrster resonance energy transfer theory calculation revealed a binding distance of 4.917 nm, substantiating the occurrence of non-radiative energy transfer between RES and CAT. Furthermore, the UV-VIS absorption spectrum, synchronous fluorescence spectrum, three-dimensional fluorescence spectrum, and circular dichroism analyses collectively demonstrated that RES induces alterations in CAT's secondary structure, augmenting the polarity around tryptophan (Trp) residues, reducing hydrophobic interactions, and bolstering hydrophilicity. This work offers novel insights into the antioxidant mechanisms of resveratrol within biological systems and holds significant theoretical and practical implications for the medical application and development of resveratrol.

Rapid and accurate quantification of trypsin activity using integrated infrared and ultraviolet spectroscopy with data fusion techniques

Proteases play a crucial role in industrial enzyme formulations, with activity fluctuations significantly impacting product quality and yield. Therefore, developing a method for precise and rapid detection of protease activity is paramount. This study aimed to develop a rapid and accurate method for quantifying trypsin activity using integrated infrared (IR) and ultraviolet (UV) spectroscopy combined with data fusion techniques. The developed method evaluates the enzymatic activity of trypsin under varying conditions, including temperature, pH, and ionic strength. By comparing different data fusion methods, the study identifies the optimal model for accurate enzyme activity prediction. The results demonstrated significant improvements in predictive performance using the feature-level data fusion approach. Additionally, substituting the spectral data of the samples in the validation sets into the best prediction model resulted in a minimal residual difference between predicted and true values, further verifying the model's accuracy and reliability. This innovative approach offers a practical solution for the efficient and precise quantification of enzyme activity, with broad applications in industrial processes.

A novel water-in-deep eutectic solvent microemulsions for chemical polishing of single crystal KDP

Microemulsion (ME) has been investigated as a chemical polishing (CP) fluid for effective polishing of single crystal potassium dihydrogen phosphate (KDP), perfectly avoiding the generation of mechanical stress. In this work, a water-in-deep eutectic solvent ME was proposed as the polishing fluid for CP of single crystal KDP. Deep eutectic solvent (DES) is formulated using n-octanol as hydrogen bond donor and methyltrioctylammonium chloride (MTOAC) as hydrogen bond acceptor, with a mass ratio of 2:1. The ME was prepared by mixing DES as the oil phase (12.5 %, wt.), a hydrochloric acid solution as the water phase (12.5 %, wt.), and isopropanol as the cosolvent (75 %, wt.), without adding any other surfactants. The properties of the ME were characterized by conductivity measurements and ultraviolet (UV) spectroscopy. The reactivity of ME with KDP was measured by the conductivity method, and it was higher at low pH values. A hydrochloric acid solution with a pH of 3 was selected as aqueous phase, considering its effects on particle size, salt loading, and static etching rate. The water content affects the polarity of ME and the final water content was determined to be 12.5 % to ensure high polarity of ME. The surface quality of the KDP crystals before and after polishing was examined using grazing incidence X-ray diffraction (GIXRD) analysis. The average roughness of the KDP crystal surface was decreased from 1.96 nm to 1.43 nm, and the root-mean-square (RMS) roughness was reduced from 2.81 nm to 1.86 nm, demonstrating a significant polishing effect. Finally, the polishing mechanism was elucidated in terms of the irreversible chemical reaction between the active components in the microemulsion and the KDP crystals.

Structural and Photometric Study of cool White Light Emitting Dy(III) Complexes Sensitized with β-diketone for Lighting Applications.

The present paper reports synthesis of five Dy(III) complexes with bidentate ligand (3-benzylidene-2,4-pentanedione) and auxiliary ligands i.e. 2,2'-bipyridyl (bipy), 4,4'-dimethyl-2,2'-bipyridyl (dmbipy), neocuproine (neo) and 1,10-phenanthroline (phen). The structural and photometric parameters of the complexes were investigated through 1H NMR, energy dispersive X-ray analysis, Fourier transform infrared, photoluminescence and ultra-violet visible spectroscopy. The optical energy gap values validated their role in semiconducting devices. These complexes exhibit suitable thermal stability revealing their utility in fabrication of white OLEDs. The emission profile of Dy(III) complexes displayed peaks at 575nm (yellow emission) and 484nm (blue emission) accredited to 4F9/2→4H13/2,15/2 transitions of dysprosium ion. The decay curve exhibit monoexponential behaviour suggesting the existence of one luminescent centre in dysprosium complexes. Moreover, their CCT and CIE coordinates value authenticate them as cool white light emitting complexes.

Fe(Ⅲ)-doped ZnIn2S4-modified graphene oxide in-situ for the degradation of tetracycline hydrochloride in simulated sunlight

To improve the efficiency of photocatalytic reactions, it is important to understand how to achieve fast directional migration and separation of photogenerated carriers at the interface. Here, Fe(III)-doped ZnIn2S4 (ZIS)-coated graphene oxide (GO) composite (GZF) was in-situ prepared via the low-temperature water bath method. Ultrathin Fe(III)-doped ZIS nanosheets were uniformly grown upright on the GO surface. The prepared samples were studied via, such as, X-ray diffraction, scanning electron microscopy combined with energy-dispersive spectroscopy, transmission electron microscopy, ultraviolet spectroscopy, N2 adsorption–desorption measurements, X-ray photoelectron spectroscopy, and electron spin resonance. Compared with ZnIn2S4 (ZIS)-coated graphene oxide (GZ), the GZF exhibit a 2.26-fold increase in the photocatalytic degradation performance of tetracycline hydrochloride (TCH) in simulated sunlight. Through density functional theory calculations, found that Fe(III) doping introduces new energy levels into ZIS, which effectively narrow its bandgap and thus enhance its light absorption efficiency. It was found that h+, ·O2−, and 1O2 were the major reactive oxygen species involved in the photocatalysis, and the effect of pH on the catalytic degradation of TCH was examined. Electron spin resonance and density functional theory results indicate that Fe(III) acts as an electron trap in the ZIS structure to promote the separation of photogenerated electron-hole pairs, which in turn enhances the photocatalytic efficiency of GZF-25.

Detection of powder samples based on UV Raman-fluorescence spectroscopy

Rapid and accurate analysis of powder samples is crucial for public safety and food security. Raman spectroscopy, noted for its many advantages, traditionally faces issues of low sensitivity and limited detection information when analyzing powder samples. This paper explores a detection method for powder samples using ultraviolet (UV) Raman-fluorescence spectroscopy. By leveraging the principles of Raman and fluorescence spectroscopy, a combined detection optical path was designed. Utilizing a 266 nm laser as the system light source, a UV Raman-fluorescence spectroscopy detection setup was constructed and seven representative powder samples were analyzed. The experimental results demonstrate that the setup effectively detects the Raman spectral features of inorganic powders like baking soda and extracts the fluorescence spectral features of organic powders such as 1,2,4,5-tetramethyltoluene. Additionally, it accurately analyzes the Raman and fluorescence spectral features of amino acids and glyphosate preparation powders. For complex powder samples with issues such as “substances with the same spectrum” and “complex and similar spectra”, UV Raman-fluorescence spectroscopy enhances spectral information dimensions, compensating for the limitations of traditional Raman spectroscopy. Furthermore, a convolutional neural network algorithm was employed to analyze the measured data of the seven powder samples increased the average recognition accuracy (AVG) from 62.53% to 98.41%. This improvement further validates the effectiveness of the proposed method in recognizing the properties of powder samples.

Detoxification of produced water from oil & gas industries using piperazine immobilized Green Fe nanoparticles

The biggest waste stream in the oil and gas sector is produced water. It is made up of both organic and inorganic wastes, both of which, if untreated, are extremely harmful to the environment. This study aims to use Fe-based nanoparticles in an attempt to detoxify produced water. Fe nanoparticles were prepared using green synthesis approach, and their stability was increased by piperazine immobilisation in a chlorinated environment. Experiments on detoxification were carried out under various circumstances in order to determine the effectiveness of detoxification. Variations in the feasible detoxification parameters, including the, the amount of Green Fe nanoparticles immobilised by piperazine, the pH of the reaction medium, the duration of the detoxification process were found to improve the detoxification efficiency. Using Ultra-violet visual ray spectroscopy and Fourier Transform Infrared Spectroscopy, the properties of the prepared Fe naoparticles were analyzed. Chemical and microstructural properties of the nanoparticles were studied using X-Ray Diffraction Spectroscopy, X-ray photoelectron spectroscopy (XPS), Field Emission-Scanning Electron Microscopy and Transmission Electron Microscopy. Detoxification experiments conducted in photocatalytic environment exhibited detoxification efficiency as high as 89.3 %.

Spectral-Sensing System for Distinguishing CH3OH and CD3OD.

Spectrally discriminating CH3OH and CD3OD, and even detecting CH3OH contents in the CD3OD solvent, are important yet have not been achieved so far, likely owing to their very similar chemical/physical properties. Herein, dynamic transesterification reactions, which can be achieved via two-step proton transfers, can be signaled via ultraviolet UV-visible (UV/vis) absorption and fluorescence spectroscopies under mild experimental conditions. Introduction of strong electron-withdrawing groups, such as -NO2, to the aromatic ring (benzoic acid moiety or phenol moiety) of carboxylate esters to activate the esters is important for transesterification reactions and is an intriguing method for modulating the selectivity of the spectral response. The rate constant of the transesterification reaction enhanced with increasing the total number of strong electron-withdrawing groups. Furthermore, the rate constants of esters in which substituent(s) are connected to the phenol moiety are higher than those of corresponding esters in which substituent(s) are connected to the benzoic acid moiety. In transesterification systems, added aliphatic amines mainly play two roles: (i) lowering the energy barrier of the first transesterification step via the formation of intermolecular hydrogen bonding in ternary systems and (ii) deprotonating the released 4-nitrophenol in UV/vis absorption spectral systems to generate an UV/vis absorption spectral signal reporter, i.e., nitrophenolate anions. As a result of the methanol-mediated transesterification reaction, spectral-sensing systems can be established for discriminating CH3OH and CD3OD and even detecting low CH3OH contents in the CD3OD solvent, owing to the kinetic isotope effect. This is the first example of spectral recognition between CD3OD and CH3OH.