Ultraviolet-visible Spectroscopy Research Articles

Studies of Structural and Optical Properties of Nickel Chloride and Glycine Doped Potassium Hydrogen Phthalate (KHP) Crystal

A semi-organic single crystal of potassium hydrogen phthalate (KHP, K(C6H4COOH.COO)) doped with Nickel Chloride (NiCl2) and Glycine (C₂H₅NO₂) was successfully harvested at room temperature to enhance the characteristics of KHP using a slow evaporation approach. The concentration of 1 mol % of Nickel Chloride and 6 mol % Glycine was used during the fabrication of the Nickel Chloride and Glycine doped KHP single crystal. Powder X-Ray diffraction (XRD), ultraviolet visible spectroscopy (UV-Vis), and Fourier transform Infrared (FTIR) analysis were used to analyze the grown single crystal. Powder XRD investigation verified an orthorhombic crystal structure and lattice parameter .To evaluate optical energy band gap and optical transparency using UV-Vis spectral. According to, FTIR analysis, and dielectric studies, it is evident that the crystal modification noticeably by adding dopant.

Silver Doped Polypyrrole Nanocomposite-based Gas sensor for Enhanced Ammonia Gas Sensing Performance at Room Temperature

Nanocomposite, which comprise organic and inorganic materials have gained increasing interest in the application for enhanced sensing response to both reducing and oxidation gases. In this study, a nanocomposite is chemical polymerization synthesized by reinforcing Ag nanoparticles with different concentration doped into the matrix of Polypyrrole (PPy). This nanocomposite is used as a sensing platform for ammonia detection with different concentration (ppm). The homogeneous distribution of Ag nanoparticles onto the PPy matrix provides a smooth and dense surface area, further accelerating the transmission of electrons. The synergistic effect of PPy@Ag matrix is responsible for the outstanding conductivity, compatibility and catalytic power of the proposed gas sensor. The structure, morphology, and surface composition of as-synthesized samples were respectively, examined via X-ray diffraction, field emission scanning electron microscopy, Ultraviolet-visible spectroscopy, Thermogravimetric analysis and Fourier transform infrared spectroscopy. The results indicated that sensor based on the PPy@Ag5 (2 gm) nanocomposite showed the highest response toward ammonia as compare to pure PPy at room temperature with a response value is 58 % to 100 ppm. Overall, the obtained findings demonstrated that the PPy@Ag nanocomposite are promising materials for gas sensing applications in environmental monitoring.

Dielectric Characteristics of Iridium Substituted Co0.05-xTi0.95O2 Dilute Magnetic Semiconductors for Electrical Device Applications

In the current study, a cost effective solid-state method have been used to prepare iridium (Ir) substituted and cobalt doped titanium dioxide (TiO2) dilute magnetic semiconductors (DMS) materials {i.e.; IrxCo0.05-xTi0.95O2; 0.00 ≤ x ≤ 0.05 DMS}. The impact of Ir substitution on structural, optical and dielectric properties for the prepared IrxCo0.05-xTi0.95O2; 0.00 ≤ x ≤ 0.05 DMS samples have been investigated using X-ray diffractometer, ultraviolet-visible spectroscopy and LCR (inductor, capacitor and resistor) meter, respectively. The structural analysis confirms the tetragonal rutile phase formation with space group p42/mnm-136, while the values of band gap energy increase with increasing Ir concentrations in prepared DMS materials and band gap value approaches the band gap energy of void band gap materials for large applications. The dielectric constant and tangent loss have been studied as a mapping of frequency (20Hz - 20MHz) at room temperature. Both the dielectric constant and tangent loss linearly decrease with increase in applied frequency and become stable at high frequency values, therefore, these DMS materials could be beneficial for storage and electrical device applications.

Influence of LaMnO3 Nanocrystallite Size on its Optical and Raman Spectra

: In the current study, nanocrystalline LaMnO3 perovskite was prepared by combustion method and annealed at different annealing temperatures. The X-ray diffraction (XRD) patterns provided evidence that the structure formed has a Rhombohedral structure with R3 ̅c space group. The remarkable growth in the crystallite size, reduction in microstrain, and dislocation density were observed with annealing temperature. Ultraviolet-visible spectroscopy was used to determine the optical band gap by the Tauc-plot method. The optical band gap was found to be 3.5 ± 0.4eV and 2.9 ± 0.5eV for 600°C and 1200°C annealed samples, respectively. The observed results were influenced by crystallite size. Raman spectra of the LaMnO3 nanocrystallites revealed five Raman-active modes, like out-of-phase rotation modes and bending mode of MnO6 octahedra. Moreover, the intensity of vibrational modes also varied significantly with annealing temperature.

Polymeric Schiff base containing phenylhydrazine and 2-thiobarbituric acid: Synthesis, characterization, antibacterial and antifungal studies

Polymeric Schiff base ligand (MFT) derived from 2-hydroxyacetophenone, phenylhydrazine, formaldehyde, and 2-thiobarbituric acid was synthesized via condensation reaction. The synthesized MFT ligand was complexed with the metal acetates of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) to form a polymeric Schiff base-metal complexes. The ligand and its metal polychelates were characterized by Fourier transform infra red (FT-IR), Ultraviolet-visible spectroscopy (UV-vis.), X-ray diffraction (XRD), Proton nuclear magnetic resonance spectroscopy (1H NMR), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and Electron paramagnetic resonance spectroscopy (EPR). The EPR spectrum of MFT-Cu(II) supported a distorted octahedral or square-planar geometry. The synthesized materials were also screened against bacterial (S. aureaus, S. mutans, B. cereus, S. pyrogenes, S. viridans, S. epidermids, C. xerosis, E. coli, K. pneumonia, P. vulgaris, P. aeruginosa) and fungal strains (A. niger, F. oxysporum, and A. oryzea). Moreover, the MFT-Zn(II) complex have demonstrated good thermal stability, as well as strong antibacterial and antifungal activities compared to the ligand and other metal polychelates.

Annealing construction of in situ heterojunction for photocatalytic degradation of bisphenol A

Here, we report the synthesis of bismuth oxyiodide (BiOI) photocatalysts with oxygen vacancy defects by a one-pot solvothermal method followed by annealing in a nitrogen atmosphere. This method allows the oxygen vacancy concentration to be tuned and provides new insights into defect engineering of photocatalytic materials. We found that the Bi2O3/BiOI heterojunction formed after annealing at 400°C significantly improves the photocatalytic performance, which provides a new strategy for the optimal design of structures for efficient photocatalysts. Using a combination of characterization techniques such as X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), as well as density-functional theory (DFT) calculations, we have elucidated the photocatalytic mechanism of the Bi2O3/BiOI heterojunctions, highlighting their role in facilitating the photogenerated charge-carrier separation and transfer. The optimized A-B40 samples exhibited photocatalytic degradation efficiencies of up to 99.7% for bisphenol A (BPA), highlighting their potential for remediation of environmental pollutants. This study presents a method for the preparation of high-performance BiOI-based photocatalysts, which offers valuable theoretical and experimental prospects for the development of eco-friendly photocatalytic materials.

Preparation of polyvinyl alcohol/carboxymethyl cellulose sodium/chitosan paper-based antimicrobial indicator cards using mixed anthocyanin with stability-colorimetric sensitivity: Monitoring freshness of carp

In this study, an anthocyanin solution with both high stability and sensitivity was successfully prepared through a blending method, and the optimal ratio was determined. Ultraviolet-visible spectroscopy analysis demonstrated that an increase in the proportion of black bean peel anthocyanins resulted in a deeper color and a more pronounced color change effect. Moreover, the stability of the blended anthocyanins was markedly enhanced with an increase in the proportion of purple cabbage anthocyanins, resulting in a slower decomposition rate under light, temperature, oxidation, and varying pH conditions. The blended anthocyanins, employed as a pH indicator, were utilized to prepare an antibacterial indicator card. It was observed that the mechanical properties of the coated paper remained unaltered by the ratio of the mixed pigments. The mixed pigments enhanced the stability of the antibacterial indicator card with respect to environmental fluctuations while facilitating more rapid and sensitive color transitions in the presence of ammonia and under disparate pH conditions. The application of indicator cards with five different anthocyanin ratios to fish resulted in a shelf life extension of 1–2 days compared to the control group and enabled real-time monitoring of fish freshness. A comprehensive evaluation demonstrated that the optimal indicator performance was attained when the mass ratio of black bean peel anthocyanins to purple cabbage anthocyanins was 1:1.

Synthesis, and Characterization of Silver Nanoparticles Functionalized with a Chalcone for Potential Antioxidant Activity

Silver nanoparticles (AgNPs) possess unusual optical, electrical, and catalytic properties. Hence, they are promising candidates in biomedical applications due to their shape and high surface area. Therefore, in present study, AgNPs were functionalized by using chalcone derivative as reducing and capping agent. The synthesized chalcone derivative was characterized by Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR), and mass spectroscopic techniques (MS). The resulting AgNPs were thoroughly characterized by different techniques, including ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), and FTIR. The monodispersed AgNPs were produced with 49.5 ±6 nm diameter based on DLS results, and TEM results showed a spherical shape with a size of 30±5 nm. Also, the absorption peak at 394 nm in the UV-Vis spectrum confirmed the production of AgNPs. The biological applications of both chalcone derivative and AgNPs as antioxidant agents were evaluated. The obtained results were promising for the development of antioxidant drugs derived from silver nanoparticles functionalized chalcone derivative with hydroxy and methoxy substituents.

Enhanced Fenton-Photocatalytic Degradation of Rhodamine B over Cobalt Ferrite Nanoparticles Synthesized by a Polyvinylpyrrolidone-Assisted Grinding Method.

A simple grinding method using polyvinylpyrrolidone (PVP) as a capping agent is introduced to synthesize CoFe2O4 nanoparticles. The effects of calcination temperature (ranging from 450 to 850 °C) on the structural, morphological, physical, and optical properties of the materials are investigated using various techniques, including thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), N2 adsorption isotherm, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), and vibrating sample magnetometry (VSM). The presence of PVP significantly suppresses the agglomeration of the materials, resulting in a nanocrystalline size of 18 nm for a sample calcined at 650 °C, which is approximately 38% smaller than that of the sample synthesized without PVP. Among the materials studied, the sample calcined at 650 °C exhibits unique properties, including optimal average pore size, specific surface area, and band gap energy, contributing to its superior photocatalytic degradation of rhodamine B via the Fenton reaction. Systematic experiments are performed to investigate the effects of pH, catalyst dosage, dye, and H2O2 concentrations and competitive anions on the rhodamine B degradation. Additionally, the Fenton photodegradation of RhB on CoFe2O4 is well-fitted to the first-order kinetic model. The redox pairs of Co(III)/Co(II) and Fe(III)/Fe(II) in the CoFe2O4 spinel structure might facilitate the formation of Fenton radicals, contributing to the decomposition of RhB through a proposed four-step mechanism. Notably, the material exhibits a strong magnetic response and maintains its excellent performance over five cycles, demonstrating the high potential for reusability as a photocatalyst.

Use of BODIPY and BORANIL Dyes to Improve Solar Conversion in the Fabrication of Organic Photovoltaic Cells Through the Co-Sensitization Method

This work addresses the implementation of the co-sensitization technique to increase the energy efficiency of organic dye-sensitized solar cells (DSSCs). Fluorescent dyes derived from boron complexes— (BORANIL) and (BODIPY)— were successfully synthesized and used as co-sensitizers in different volume percentage ratios to verify the most effective concentration for photon capture through these sensitizers. The dyes were optically characterized using ultraviolet–visible spectroscopy (UV-VIS) and Fourier transform infrared (FTIR), analyzing them through the optical performance of each hybrid combination of dyes, an optimization of the photon collection capacity in the tests performed in a volume percentage ratio of 25:75 or 1:3. The morphology and surface roughness of the electrodes were analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Through electrochemical characterizations, it was found that the highest photovoltaic conversion efficiency was obtained with the ATH1005 (D) dye mixed with ATH032 (G) in the proportion of 25%:75% or DG 1:3, with efficiency (η) of 3.45%, against 2.43% and 1.90% for DG 1:1 and DG 3:1 cells, respectively. Cells with BODIPY dyes also present higher conversion efficiencies compared to BORANIL cells. The results corroborate the presentation of organic solar cells as a viable option for electricity generation.

Synthesis and photocatalytic activity of Ag/AgCl for removal of BTX vapors under visible light: modeling by ANN

Abstract Among volatile organic compounds, benzene, toluene, and xylene (BTX) are the most harmful organic compounds and the removal of these harmful compounds is mandatory. In the current study, Ag/AgCl composite was successfully synthesized via deposition–precipitation along with the photoreduction method. The scanning electron microscopy, x-ray powder diffraction, photoluminescence spectroscopy, Fourier transform infrared spectra, and ultraviolet-visible diffuse reflectance spectroscopy were employed to characterize the synthesized products. The photocatalytic property of the products was investigated by evaluating on photodegradation of BTX vapors under the radiation of visible light. The results showed that Ag/AgCl exhibits enhanced visible-light photocatalytic activity compared with AgCl. The strong surface plasmon resonance of metal Ag nanoparticles anchored on the AgCl surface can be responsible for the enhanced visible-light photocatalytic activity of the Ag/AgCl. The influence of the basic operational parameters such as type of BTX, the concentration of BTX, photocatalyst shape, relative humidity, and radiation time on the removal efficiency of BTX was studied. The data obtained from removal tests were modeled by a three-layered feed-forward artificial neural network. The optimized ANN architecture was strong at predicting the removal efficiency of the BTX contaminants with R2 > 0.99 and a very low mean square error. The sensitivity analysis using Garson’s method displayed that all explored process parameters influence the photocatalytic removal of the BTX contaminants. The obtained ANN model is used to predict the photodegradation of BTX at different conditions.

Nanoparticle-protein interactions: Spectroscopic probing of the adsorption of serum albumin to graphene oxide‑gold nanocomplexes surfaces

Graphene oxide‑gold nanocomposites (GO-AuNCPs) are promising candidates in nanomedicine. They will inevitably bind with biomolecules such as serum albumin (SA) in the body while they enter the organism. The interaction between GO-AuNCPs and human serum albumin (HSA)/bovine serum albumin (BSA) were investigated by using multispectroscopic methods, elucidating the binding principles through molecular simulations. The results of ultraviolet-visible (UV–vis) absorption spectroscopy and steady-state fluorescence spectroscopy indicated that GO-AuNCPs interacted with HSA/BSA with different degrees of interaction. The binding of GO-AuNCPs and HSA/BSA was a spontaneous endothermic reaction, and the quenching mechanism is static quenching. The binding constant (Ka) value of BSA binding to GO-AuNCPs at the same temperature was greater than that for HSA, indicating a stronger affinity of BSA for GO-AuNCPs. Molecular simulation revealed that the binding sites of GO-AuNCPs on HSA/BSA were located within the slits of the subdomains IB and IIIA, rather than within any known binding regions. This significant finding was validated by using of site markers phenylbutazone (PB) and flufenamic acid (FA). Synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, and circular dichroism (CD) spectroscopy showed that the conformation of HSA/BSA was altered upon the addition of GO-AuNCPs, resulting in slight structural changes of tryptophan and tyrosine residues. Although the secondary structure of HSA/BSA was changed, the α-helix remained dominant. The results provide a theoretical and experimental foundation for developing of safe and effective nanomaterials, which is of great theoretical significance.

Synthesis of a highly stable Mo-Fe bimetallic metal-organic framework and its catalytic activity for the selective oxidation of sulfides under mild conditions.

A novel Mo-Fe bimetallic metal-organic framework [Fe2(4,4'-bipy)Mo2O8]·2H2O (1) was synthesized and characterized by X-ray single crystal diffraction, infrared spectroscopy (IR), thermogravimetric analysis (TGA), ultraviolet-visible spectroscopy (UV-vis), and its magnetic properties were studied. The compound demonstrates insolubility in most solvents and exhibits significant chemical stability across a wide pH range. Typically, exceptional selectivity and efficient conversion of sulfides to sulfoxides using 1 with H2O2 have been verified under ambient conditions.

Synthesis, characterization, and biological activity of silver nanofibers essential oils of prunus dulcis

Background Prunus dulcis possesses various beneficial qualities, including liver-protective, cardio metabolic, antimicrobial, anti-inflammatory, and anxiety-reducing properties. Furthermore, the oil is a fantastic moisturizing cream for hair and skin, to it can help prevent stretch marks and ultraviolet-visible spectroscopy damage. These biological applications highlight the importance of developing nanotechnology applications for P. dulcis almond oils. Materials and methods In this study, essential oils derived from the fruit of the almond tree (P. dulcis) were employed as reducing agents for producing silver nanofibers (AgNFs). Synthesized AgNFs were characterized using ultraviolet-visible spectroscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. The biological activities of (AgNFs) were examined. Results The current study showed the absorption of synthesized (AgNFs) at 415 nm. Scanning electron microscopy analysis showed the nanofibers average diameter varied from 200 nm to 10 nm. The biological activities of (AgNFs) were evaluated using minimum inhibitor concentration, half-maximal inhibitory concentration (IC50), and flow cytometry tests. The cell cycle test of (AgNFs) showed it arrested with S-phase of two types of human cancer cells (HepG2 liver cancer cells and MDA-MB-231 breast cancer cells). Conclusion These antibacterial and anticancer properties of AgNFs highlight the increased medicinal value of essential oils when coupled with AgNFs produced from almond essential oil.

Fabrication of BiVO4/Ag2CrO4 heterojunction composites modified with graphene oxide for enhanced photoelectrochemical and photocatalytic performance.

A novel GO/BiVO4/Ag2CrO4 heterojunction photocatalyst was prepared by depositing Ag2CrO4 on the highly active (040) facet of BiVO4, followed by incorporating graphene oxide (GO) through an in situ precipitation method. This synergistic modification of BiVO4 by Ag2CrO4 and GO results in excellent photocatalytic performance, with a degradation efficiency of 94.6% coupled with a maximum rate constant of 0.223 min-1, which is 2.40, 2.19 and 0.66 times higher than that of BiVO4, Ag2CrO4, and BiVO4/Ag2CrO4, respectively, for the degradation of ciprofloxacin (CIP) under visible light irradiation. The degradation efficiency of ciprofloxacin was evaluated using total organic carbon (TOC) analysis. Under investigated conditions, the GO/BiVO4/Ag2CrO4 photocatalyst achieved a TOC reduction of 63.4%. The enhanced photocatalytic performance is attributed to the beneficial role of GO in facilitating electron transport for photo-charge carrier migration, leading to strong interfacial coupling between BiVO4 and Ag2CrO4, which in turn promotes efficient charge separation and transfer. The physicochemical properties of the fabricated heterojunction photocatalysts were characterized using X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX) analysis, Brunauer-Emmett-Teller (BET) analysis, Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) emission spectroscopy, while the photoelectrochemical properties of the fabricated photocatalyst were investigated through electrochemical impedance spectroscopy (EIS), Mott-Schottky plots, and photocurrent response analysis. The scavenging experiment was conducted to confirm the role of H+ and ·O2 - in the photocatalytic degradation of ciprofloxacin, which aids in proposing probable degradation mechanism for ciprofloxacin under visible light irradiation. Hence, this study offers an effective strategy for fabricating heterojunction photocatalysts aimed at enhancing the photodegradation of pollutants in wastewater.

Rapid Correction of Turbidity Interference on Chemical Oxygen Demand Measurements by Using Ultraviolet-Visible Spectrometry

We developed a simple, rapid, and high-precision method to compensate for the turbidity interference in the measurement of water parameters using ultraviolet-visible spectrometry. By combining direct orthogonal signal correction (DOSC) with partial least squares (PLS), we corrected the full spectra (220 nm to 600 nm), significantly enhancing the accuracy of the water parameter calculations. First, DOSC was applied to filter out turbidity-related components, retaining only the spectral elements most closely associated with the target substance, without requiring a standard baseline for the turbidity effect. Then, 13 wavelengths were selected from the corrected full spectra to construct the discrete absorption spectra. Further, a PLS regression model was established based on the corrected discrete absorption spectra and their corresponding concentrations. In our experiment, this method effectively eliminated the blue shift and peak height reduction caused by turbidity, especially in shorter wavelengths, which are more sensitive to interference. Moreover, when applied to new samples, the correlation coefficients (R2) between the predicted and actual values improved from 0.5455 to 0.9997, and the root mean square error (RMSE) decreased from 12.3604 to 0.2295 after correction. Overall, the DOSC-PLS method, together with ultraviolet-visible spectrometry, posed a great potential for the precise monitoring of target water parameters in field studies.

Fabrication of 4-methoxyphenol chemical sensor with graphene oxide conjugated binary Co3O4/Y2O3 nanocomposite by linear sweep voltammetry

Combining binary metal nanoparticles (MNPs) with two-dimensional materials can create innovative nanocomposites with unique physical and chemical properties, which are particularly useful for developing efficient electro-chemical sensing systems. This study presents a unique approach for detecting and validating the hazardous substance 4-Methoxyphenol (4-MP) electrochemical approach with conjugated nanocomposite (NC). This approach utilizes an electrochemical sensor constructed on a glassy carbon electrode (GCE), modified with hybrid composite material including graphene oxide (GO) conjugated binary yttrium oxide (Y2O3) and cobalt oxide (Co3O4) as GO@Co3O4/Y2O3 NCs. After preparing the NCs using the solid-state chemical method, various techniques were used to characterize the materials by using various techniques including Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Ultraviolet–Visible Spectroscopy (UV/Vis), Brunauer–Emmett–Teller Surface Area Analysis (BET), and Transmission Electron Microscopy (TEM). Cyclic voltammetry (CV), linear sweep voltammetry (LSV), and impedance spectroscopy (EIS) were used to examine the electrochemical characterization and sensing application of the fabricated electrodes. Under standard laboratory circumstances, we used LSV to measure the 4-MP detection limit, which linear dynamic range (LDR) from 0.67 to 2.08 M. Based on the calibration curve’s slope, the sensor’s sensitivity was found to be 2.9 µAµM−1cm−2. It was calculated the limit of quantification (LOQ) of 0.19 M and a lower limit of detection (LOD) of 0.057 M. Compared to other modified electrodes for 4-MP detection, the composite electrode demonstrated superior electrocatalytic performance. The GO@Co3O4/Y2O3 NCs sensor demonstrates excellent selectivity, even among several interfering substances and metal ions. For optimization, different phosphate buffered saline (PBS) solutions with pH values ranging from 5.7 to 8.0 were used to evaluate the sensor activity. The sensor’s effectiveness in detecting unknown 4-MP concentrations was tested in various real-samples, including seawater, industrial wastewater, tap water, and well water, using a standard addition method. This study introduces a new approach for developing an electrochemical sensor aimed at monitoring environmental chemicals. The sensor incorporates cobalt nanoparticles on carbon materials to introduce the inorganic-carbon composite materials for the safety in environmental and healthcare applications on a large scale.

Synthesis and characterization of fluorenone derivatives with electrical properties explored using density functional theory (DFT)

This study provides thorough computational and experimental assessments of four types of novel synthesized thiosemicarbazones. The compounds were effectively synthesized using a condensation reaction between thiosemicarbazide and fluorenone, producing a remarkable range of 70–88%. Additional chemical structures were examined utilizing spectroscopic methods, including Fourier-transform infrared spectroscopy (FTIR), NMR spectroscopy, and ultraviolet-visible spectroscopy. The computational analyses utilized DFT using the M06/6-311G (d, p) technique. The electrical characteristics, including the stability of orbitals via energy exchange between a donor and acceptor, can be evaluated by natural bond orbital (NBO) analysis. The nonlinear optical (NLO) properties were analyzed to detect any prohibited energy gaps. FTIR and UV-visible data were computed using the identical M06/6–311G (d, p) level of theory. The NBO test has confirmed the occurrence of charge separation due to the efficient transfer of electrons from the donor to the acceptor unit over the π bridge. The molecular chemical softness and hardness are dependable indications of a molecule’s chemical stability. A significant magnitude of the absolute value of polarizability and hyper-polarizability indicates considerable dispersion of electric charge. The outcomes derived from Density Functional Theory (DFT) generally align well with experimental findings.

Catalytic degradation of various dyes using silver nanoparticles fabricated within chitosan based microgels

Precipitation polymerization method was used to synthesize chitosan based poly[chitosan-N-isopropylmethacrylamide-acrylic acid] [P(CS-NI-AA)] microgel particles. Synthesized P(CS-NI-AA) microgel particles were utilized as micro-reactors for the fabrication of silver nanoparticles (AgNPs) inside the structure of microgels through chemical reduction of Ag+ ions using NaBH4 as reducing agent. P(CS-NI-AA) and Ag-P(CS-NI-AA) systems were analyzed using various characterization techniques like scanning electron microscopy (SEM), ultraviolet-visible (UV–visible) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Catalytic activity of Ag-P(CS-NI-AA) for individual and simultaneous degradation of various dyes like methylene blue (MB), Congo red (CR), brilliant blue (Bb), methyl orange (MO) and Rhodamine B (RB) was investigated in aqueous phase using NaBH4 as reductant. The Pseudo 1st order rate constant (k1) for dyes degradation were evaluated. The Ag-P(CS-NI-AA) hybrid system was observed to be efficient, low-cost and stable catalyst for quick degradation of dyes.

Development of an Attenuated Total Reflectance-Ultraviolet-Visible Probe for the Online Monitoring of Dark Solutions.

Optical spectroscopy is a valuable tool for online monitoring of a variety of processes. Ultraviolet-visible (UV-vis) spectroscopy can monitor the concentration of analytes as well as identify the speciation and oxidation state. However, it can be difficult or impossible to employ UV-vis-based sensors in chemical systems that are very dark (i.e., have a high optical density), requiring exceedingly short path lengths (for transmission approaches) or an effective means of backscattering (for reflectance approaches). Examples of processes that produce highly absorbing solutions and that would benefit significantly from the diagnostic potential of optical sensors include used nuclear fuel recycling and molten salt systems with high concentrations of dissolved uranium. Utilizing an attenuated total reflectance (ATR) UV-vis approach can overcome these challenges and allow for the measurement of solutions orders of magnitude more concentrated than transmission UV-vis. However, determining ideal sensor specifications for various processes can be time-consuming and expensive. Here, we evaluate the ability of a novel ATR-UV-vis probe to measure very concentrated solutions of Co(II) and Ni(II) nitrate as well as organic dyes (methylene blue, acid red 1, and crystal violet). This sensor design provides a modular method for exploring possible "path lengths" by altering the length of the ATR fiber that was submerged within solution during spectral measurements. Measurements within the ATR sensor cell were compared to measurements gathered by transmission UV-vis of samples within a commercially available 1 cm optical cuvette. The ATR-UV-vis probe was capable of measuring absorbance of solutions with a chromophore concentration 600 times greater than that in the 1 cm cuvette. Advanced data analysis in the form of multivariate curve resolution (MCR) was used to analyze the speciation of methylene blue over a large concentration range. The application of this novel ATR-UV-vis probe to the investigation of dark solutions is a promising avenue for use in online monitoring of nuclear processes.