جستجوی مقالات مرتبط با کلیدواژه « FT-IR » در نشریات گروه « علوم پایه »

The effect of cationic surfactant chain length on chromium VI (Cr(VI)) adsorption behavior on Magnetic NanoParticles (MNPs) was examined in this work. To alter the surface of MNPs, we used a variety of alkyl trimethylammonium bromide surfactants, such as cetyltrimethylammonium bromide (C16TAB), tetradecyl trimethylammonium bromide (C14TAB), and decyl trimethylammonium bromide (C10TAB). Aqueous solutions containing known amounts of Cr(VI) were used in the adsorption studies. Fourier Transform InfraRed (FT-IR) spectrophotometry, transmission electron microscopy (TEM), and powder X-ray diffractometry (XRD) were used to analyze the Functionalized MNPs (CnTAB@MNPs). In order to evaluate the impacts of several parameters on chromium removal efficiency (RE), we conducted statistically planned batch experiments. These parameters included surfactant chain length, initial chromium concentration, solution pH, interaction time, adsorbent dose, and added salt. Our findings showed that the adsorption capacity of magnetic nanoparticles for Cr(VI) was considerably impacted by the chain length of the cationic surfactant. Compared to MNPs functionalized with shorter alkyl chains, those functionalized with longer alkyl chain surfactants showed better adsorption capabilities. Additionally, we found that the adsorption efficiency was influenced by a number of variables, including pH, the chemical reduction of Cr(VI) to Cr(III), and the interactions between the negatively charged Cr(VI) ions and the cationic surfactant via electrostatics. Using CnTAB@MNPs, Cr(VI) was effectively removed at low pH values; however, removal was negatively impacted by a rise in pH. After 7 minutes and 30 seconds of contact time, we reached an Cr VI, RE of 95.77% at pH = 4, nanoparticles dosage = 12 g/L, and initial [CrVI]= 98 mg/L.

Grevillea robusta is widely used in the carpentry industry due to its long life and strength but the saw dust wastage is just thrown out as manure. This work focuses on analyzing the properties of sub-fractions obtained from the pyrolysis of sawdust of Grevillea Robusta (GR). Pyrolysis was done in a top-loaded fixed bed pyrolysis reactor at 500˚ C temperature, a heating rate of 30° C/minute, and a particle size of 2-3 mm (average). Pyrolysis reactor temperatures were analyzed using Thermo-Gravimetric Analysis (TGA). The by-products were analyzed by techniques like Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FT-IR) spectroscopy, Gas Chromatography (GC), and Gas Chromatography coupled with Mass Spectrometry (GC/MS) techniques along with physiochemical characterization carried out using ASTM (American Society for Testing Materials) D-7544 standard. A thermal study reveals that the higher decomposition of biomass sample occurred in the temperature of 345-370 ˚C. There were 35 components found in the pyrolysis oil with varying carbon lengths of C3 – C44. The proximate and ultimate analysis responses clearly show that the calorific value of pyrolysis oil is increased by 112.88% than that of the biomass sample. Meanwhile other properties like fixed carbon, and nitrogen (N2) content increased whereas moisture content decreased in biochar than the biomass sample, which confirms the presence of hydrocarbons in the pyrolytic gas released out of the reactor. Sawdust, which is often considered a waste product in the forestry, furniture, and woodwork-based industries, can be converted into useful energy. The current study intends to investigate the various forms of energy, such as biofuels or biomass-based power generation. This conversion process can create new economic opportunities, including job creation in the biomass industry, reduced energy costs for businesses and households, and decreased dependence on imported energy sources. These analyses confirm that the by-products can be used efficiently as substitutes for conventional fuel.

This work reports on an inhibition and adsorption performance study of two quinazoline derivatives ((2-(2-chlorophenyl)-2,3-dihydroquinazolin-4(1H)-one) and (2-(2,4-dichlorophenyl)-2,3-dihydroquinazolin-4(1H)-one)) named ZB3 and ZB4, which were synthesized and examined using carbon nuclear magnetic resonance (13C NMR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The assessment of the corrosion prevention of these two compounds for MS in 1.0 M HCl was performed employing potentio-dynamic polarization (PDP) and (EIS) electronic impedance spectroscopy. The experiments performed showed that both derivatives operate well to prevent corrosion and their efficiencies exceed 85% at a concentration of 10-3. Moreover, it is discovered that the three chemicals' adsorption on the m-steel surface complies with Langmuir adsorption isotherm equation. The m-steel surface submerged in the corrosive solution was characterized by scanning electron spectroscopy (SEM) in conjunction with energy dispersive spectroscopy (EDS), spectroscopy using atomic force microscopy (AFM), X-Ray diffraction, and FTIR analysis. The findings showed that the examined inhibitors are well adsorbed, generating a barrier layer for the m-steel's surface. DFT calculations and Monte Carlo (MC) simulation were used to directly correlate the electronic and adsorption properties, respectively, with the experimental corrosion inhibition efficiencies obtained for quinazoline and its 2 investigated derivatives.

Chlorination of 3-acetyl-4-methylthioquinolin-2(1H)-one (1) with sulfuryl chloride may lead to 3-(2,2-dichloroacetyl)-4-methylthioquinolin-2(1H)-one (2). Whereas analytical and spectral results  for the product of this reaction evoked the proposal of obtaining 3-chloro-4-hydroxyquinolin-2(1H)-one (3), which was found by reduction of 3,3-dichloroquinolin-2,4-dione.  Density Functional Theory (DFT) and time-dependent density functional theory (TD-DFT) calculations of the electronic structure at the B3LYP/6-311++G (d,p) level of theory were used to investigate the geometries, linear polarizability ⟨Δ𝛼⟩, first order hyperpolarizability ⟨𝛽⟩, natural bonding orbital (NBO), molecular electrostatic potential contours (MEP&ESP), electrophilicity (ω), and UV-Vis spectra, in both ethanol and dioxane solvents for compound 3. The geometrical and energetic characteristics have been thoroughly studied to determine why compound 3 was formed instead of another expected result compound 2. At the same time, the thermo-chemical parameters, NMR, harmonic vibration frequencies, and equilibrium geometries were computed. The calculated acidity constant (pKa) for the protonated and deprotonated forms in ethanol for the present compound 3. Band maxima (λmax) and spectra intensities are reflected as blue and red shifts in the solvent dependence. The excited state was identified and contributed to the electronic configurations. Finally, DFT calculations were used to connect the structure-activity relationship (SAR) with real antibacterial results for compound 3.

Nano sized bimetallic oxide materials have been extensively studied worldwide because of their unique properties such as electrical conductivity, magnetic property and superior mechanical properties. The exercise objects the synthesis, characterization and studies like thermal and electrochemical study of the barium cerate (BaCeO3). The facial approach to preparing well dispersed nanocrystals of (BaCeO3) was prepared by oxalate precursor method. Barium oxalate and cerium oxalate precursors were prepared by direct dispersion of barium and cerium salt into oxalic acid solution separately. These precursors are undertaken for self-propagating combustion reaction under the influence of polyvinyl alcohol (PVA) fuel in the weight ration 1:1:5 to form BaCeO3 as required product. X-Ray diffraction (XRD) tool which is used to study the structural confirmation of prepared bimetallic oxide nanomaterials sample. The presence of a 100% peak (110) along with other reflections in the pattern confirms the sample. Morphological study of the sample was carried out by scanning electron microscope (SEM) tool. Bonding nature of the sample was well studied by Fourier transfer infrared (FT-IR) instrumentation. Metal confirmation in the prepared sample was identified by EDX analysis. Absorption variation was well analyzed by UV-Vis spectroscopy. Maximum absorption band at 425 nm signifies the sample phase. Raman spectroscopic (RS) study was undertaken to view its structural organization. Dynamic light scattering (DLS) study was implemented to know the size of the sample. Cyclic voltammetry (CV) and thermal gravimetric analysis (TGA) studies are also experimented to know the electrolytic and thermal behavior of the barium cerate sample. Complete decomposition of the sample takes place at 779.41oC records thermal stability.

Harmaline and harmine, are the major ß-carbolines present in the seeds of the Peganum harmala L. These compounds are known as herbal active principals with potential use in pharmaceutical and medicine. To assess the growth inhibitory effect of phyto-alkaloids, harmaline and harmine, on cancer cell lines. The P. harmala L.’s alkaloids were extracted by acidic/basic extraction method and identified by two methods, Fourier Transform Infra-Red Spectroscopy (FTIR) and High-Performance Liquid Chromatography (HPLC). breast cancer cell lines, MDA_MB_231, were subjected to different concentration (1–100 μg. mL -1) of the P. harmala extract at different time courses (24h, 48h). Methylthiazol Tetrazolium (MTT) test, the half maximal inhibitory concentration (IC50) and the morphological changes through optical microscopy were evaluated cell lines, the P. harmala extract decreased cell viability in longer time exposure in a dose dependent manner. The more concentrated extract led to higher motility of MDA-MB-231 at 24h.It was observed that 30 μg. mL -1 is the minimum lethal dose that kills approximately 50% of cells at 24 hours in MDA-MB-231 cell line (IC50). The morphological observation ensured the apoptosis nature of P. harmala on cells as their membrane kept intact and no membrane permeabilization was observed. The results revealed that the P. harmala extracts decreased significantly growth rate and cell survival of cancer cell lines. higher growth inhibition of MDA-MB-231 cell line by the P. harmala extract was confirmed.

In this study for wastewater remediation, we aimed to prepare Environmentally Sensitive Hydrogels (ESHs) with specific properties to remove copper (Cu2+) from wastewater. ESHs were prepared with inter-complex and amphoteric properties by the free radical polymerization method. We prepared two monomers, vinylpyrrolidone (VP) and Methacrylic Acid (MA). N,N'-methylenebisacrylamide was a cross-linker agent to prepare ESHs for binding Cu2+ to remove from wastewater. To characterize the structural behavior of synthesized ESHs, we used FT-IR. Thermal properties were investigated by using TGA. We used Scanning Electron Microscopy (SEM) micrographs for morphologic studies. Swelling and diffusion studies were performed at different pH, temperatures, and salt solutions. The amphoteric property and inter-complex formation between VP and MA were monitored by UV spectroscopy. In the Cu2+ bindings onto ESH experiments, a Langmuir-type (L) adsorption was observed regarding the Giles classification system. Binding parameters such as equilibrium constant (KL), monolayer coverage (Qm), and maximum fractional occupancy (FO%) were calculated as 0.16 L 1/gESH, 30 MgCu2+1/gESH, and 81%, respectively. We found a powerful electrostatic effect between the ionic part of ESH and cationic Cu2+. These interactions denote the removal of cationic heavy metals and organic toxic wastes for water treatment.

Sargassum Vulgare was used as an effective biosorbent for the removal of Fe3+ from aqueous solutions. Results for batch operation are presented for biosorption onto algal biomass, raw and modified with HNO3, HCl, NaCl, and CaCl2. NaCl was selected as the best modifier for the algae surface for the improvement of the sorption capacity. Optimum biosorption conditions were determined as a function of contact time, biomass dosage, initial metal concentration, and temperature.
The Langmuir isotherm yields high regression values for a maximum monolayer sorption capacity of the modified biomass of 30.52 mg/g at optimum conditions (pH = 2, dose = 5 g/L, t = 120 min, and T= 298 K). This represents an increase of more than 50 % concerning the raw algae. The kinetics of sorption followed the pseudo-first-order rate equations and is fast enough to prove the technique feasible. The thermodynamic parameters showed that the adsorption of Fe3+ using algal biomass was feasible, spontaneous, and exothermic. Modified algae could be regenerated once using 0.001M EDTA solution, and a recovery of 90% of Fe3+ was obtained. Fourier Transform InfraRed (FT-IR) spectroscopy and Scanning Electron Microscopy (SEM) were used to characterize the surface of modified algae.

In this study, the structure optimized and calculations of the electronic properties for the study of two compounds which are 2 is Diethyl {5-[(2-hydroxy-5-methylphenyl) carbonyl] -2-thioxo-1,2,3,4-tetrahydropyrimidin-4-yl}-phosphonate (2), compound 4 is Diethyl {6-amino -1-(4-chlorophenyl) -5-cyano-3- [(2-hydroxy-5-methylphenyl)carbonyl] -1,2- dihydropyridin-2-yl]}phosphonate (4) have been performed by using the DFT method at the B3LYP/6-311++G (d, p) theory level. UV-Vis spectra, in both methanol and dioxane solvents, have been employed for two compounds 2 and 4 by density functional time-dependent theory (TD-DFT) calculations at the same level of calculation. The method of Coulomb-attenuating (CAM-B3LYP) and Corrected Linear Response Polarizable Continuum Model (CLR) PCM studied for theoretically obtaining the absorption electronic spectra in the gas phase, methanol, and dioxane, respectively; indicate a good agreement with the observed spectra and FT-IR, vibrational spectra were calculated. The GIAO method calculated the 1H and 13C NMR chemical shifts theoretically values which reflect better coincidence with the experimental chemical shifts. The dihedral angles result of calculations shows that two compounds 2 and 4 are non-planar. The stability of the two compounds 2 and 4, the hyper conjugative interactions, and the delocalization of the atomic charges was analyzed with the Natural Orbital Bond analysis (NBO). The relocation of electronic density and electronic structures were discussed. Studied functional density local descriptors, (MEP) Molecular Electrostatic Potential, molecular border orbitals, and absorption spectral. Analysis of the global descriptors revealed that compound 4 is the most reactive with an energy difference between the border orbital of ΔEgap = 3.605 eV. Furthermore, this compound 4 is the less stable, the softest, and has the greatest electronic exchange capacity of the other compound 2 studied. Studied by DFT calculations (SAR) structure-activity relationship and contacted with practical antimicrobial results for compounds 2 and 4.

Bisphenol-A, formaldehyde, and epichlorohydrin form hexafunctional epoxy resin. The curing behavior of resin has been evaluated by using five different hardeners viz. diethyl triamine, triethyl tetraamine, phenalkamine, polyamido amines, and polyamides. The resin was further characterized by epoxy equivalent weight, hydrolyzable chlorine content, volatile content, viscosity and rise in viscosity, weight average molecular weight, and Fourier Transform InfraRed (FT-IR).  spectroscopy The hexafunctional epoxy resin was used for the preparation of jute and glass-reinforced composites. All composites were characterized by their mechanical properties, thermal properties, and chemical resistance.

Our present study provides a detailed knowledge on structure and spectroscopic properties of 2-ethyl-2-phenyl malonamide. The optimized geometrical parameters, vibrational wavenumbers and electronic spectra have been theoretically done by Density Functional Theory (DFT) employed with B3LYP 6-311++G(d,p) basis set. The experimental vibrational wavenumbers were characterized by Fourier transform infrared (FT-IR) and Fourier Transform Raman (FT-Raman) spectroscopy were recorded in the region 4000-400 cm-1. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts have been calculated using Gauge Independent Atomic Orbital (GIAO) method. The UV-Vis spectrum was recorded in gas phase and compared with theoretical spectrum. Other molecular properties such as Natural Bond Orbital (NBO) analysis was also carried out to determine stability and charge delocalization, molecular electrostatic potential surface was generated to study the electrophilic and nucleophilic sites of the title compound, Finally the calculated theoretical findings show good agreement with observed spectra to confirm the structure of 2-ethyl-2-phenyl malonamide.

ZnS-MoS2 Nanocomposite was synthesized by a cost-effective and eco-friendly hydrothermal approach to investigate the structural and optical properties of ZnS-MoS2 nanocomposite powder comparing with the pure ZnS and MoS2. The structural, morphological and optical absorption properties of prepared powder samples were characterized by Powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), Diffusion reflectance spectrophotometer (DRS), FT-IR-Fourier transform infrared spectroscopy. Powder XRD results show both cubic phase and hexagonal phase structures of ZnS and MoS2. The average crystallite size lies between 20 nm to 25 nm for hydrothermally prepared nanocomposite. The dislocation density and lattice strain were also calculated. The surface morphology of the prepared nanocomposite shows spherical hexagonal flowers with agglomerations. With coupling of ZnS-MoS2, there is a slight variation in the energy band gap that slightly shifted from 3.61 to 3.57 eV and it is found to be red-shifted. The characteristic frequencies related to ZnS-MoS2 nanocomposite and other precursors related molecules are disclosed from FT-IR spectra.

The (3,5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)(phenyl)methanone (DPPPM) were synthesized by using rapid and recyclable reaction media polyethylene glycol-400 (PEG-400) and catalytic amount of acetic acid. This method gives remarkable advantages such as simple workup and a greener method by avoiding hazardous and toxic solvents. The computational calculations for title compound have been carried out by using DFT method with B3LYP hybrid functional and 6-311++G (d, p) basis set. The structural parameters like bond lengths, bond angle, and dihedral angles were obtained from the optimized molecular geometry and discussed. This structural analysis shows, the DPPPM molecule has non-planar structure and possess C1 point group symmetry. The infrared vibrational spectral bands assignments were made by correlating experimental findings with the computed data and results shows good agreement. The electronic spectral properties were explored using the time-dependent density functional theory (TD-DFT) in the gas phase and two different polarity solvents. This obtained theoretical UV-Visible absorption results are in acceptable concurrence with the UV-Visible absorption experimental results. The solvent effect on wavelength of absorption also been reported. The frontier molecular orbital, MESP and global chemical reactivity parameters for the title molecule in the gas phase were reported and discussed. Theses result shows molecule possesses good strength and stability.

In the present work, synthesis and DFT study of 2-(4-fluorophenyl)-5-phenyl-1,3,4-oxadiazole is reported. The 6-311++G (d,p) basis set was used to optimize the molecular structure of the title compound using the DFT/B3LYP method.The structural parameters, bond length, and bond angle were studied. The fundamental vibrational wavenumbers and intensities were computed, and the observed and calculated wavenumbers were found to be in excellent agreement.  In order to decide the reactivity and possible site for electrophilic and nucleophilic, Frontier molecular orbital (HOMO-LUMO) energies, global reactivity descriptors, molecular electrostatic potential as well as Mulliken charges were calculated using the same theory. The obtained results indicates that the compound possess good kinetic stability. The molecular electrostatic potential surface analysis shows that the nitrogen atom oxadiazole ring is the binding site for electrophilic attack.

PVC/NiFe2O4/Fe2O3 compositewas successfully synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). Also, the catalytic activity of PVC/NiFe2O4/Fe2O3 has been considered in the synthesis of two arylidene barbituric acid derivatives. The FT-IR and XRD results confirmed the synthesis of PVC/NiFe2O4/Fe2O3 composite. According to Scherre equation and the main peak at about 2θ = 41.72º, the average crystalline size of the nanoparticles determined at about 75 nm. Catalytic activity results show that the as-prepared composite is as an efficient catalyst. This study suggests that other PVC composites could be explored as a new catalyst for synthesis of other arylidene barbituric acids.

It was shown that the structure and particle size of zirconia nanoparticles has been controlled through the homogeneous precipitation process by using templates. Hexamine as the template led to ZrO2 nanoparticles with tetragonal structure, whereas coffee extract favored monoclinic structures. Field Emission Scanning electron microscopy (FeSEM), Transmission electron microscopy (TEM) measurements, Infrared and Raman analysis were used to view how the structure may possibly affect their spectrum characteristic.  Using these pure m- and t-ZrO2 phases as catalyst, were studied photocatalytic degradation of ciprofloxacin (CIP). Higher degradation efficiency (50%) of the drug was observed at pH5.5 after 15 min using t-ZrO2 phase.

In the present work, the objective is to determine the potential use of natural materials, Luffa cylindrica cords for the removal of Chrome (VI) through the adsorption batch process under different experimental conditions. The determination of the concentrations of Chrome (VI) has been performed using a UV - visible spectrophotometer. Adsorption studies were carried out under various parameters such as contact time, pH, initial concentration, and temperature. The results obtained show that Luffa cylindrica cords/Chrome (VI) have an adsorption capacity of 29.98 mg/g. The adsorption process was rapid and reached equilibrium in 60 min of contact at 343K and pH 7.7. The different adsorption models Langmuir, Freundlich, Temkin, and Elovich were used for the mathematical description of the adsorption equilibrium, and it was found that the very well - equipped experimental data for the Langmuir model (R2=0.9700), the pseudo-first-order and pseudo-second-order kinetic models were applied to the experimental data. The experimental data fitted very well the pseudo-second-order kinetic model (R2= 0.982) and also followed the model of intraparticle diffusion (Kdif vary from 0.687 to 4.040 mg/(g min1/2) for concentrations between 25 and 150 mg/L), whereas diffusion is not the only rate - control step. The thermodynamic parameters study shows that the negative value of ΔH° (-11.49 kJ/mol) indicated that the adsorption of Chrome (VI) on Luffa Cylindrica cords was exothermic, the reaction was accompanied by a decrease in entropy (- 0.033 kJ/K. mol). The Gibbs free energy increased from -0.171 to -1.722 kJ/mol, respectively for Chrome (VI) when the temperature was increased from 296 to 343 K. The studied system shows that the adsorption process is spontaneous. The physical properties of the biosorbent were determined by FT-IR analysis and X-RD.