جستجوی مقالات مرتبط با کلیدواژه « s » در نشریات گروه « شیمی »

This study investigates water treatment for drinking water production using an integrated system combining the internal loop airlift technique and electrocoagulation. Synthetic solutions with defined turbidities were prepared for experimentation. The airlift reactor comprises two compartments, the Riser and the Downcamer, with aluminum electrodes powered by a variable-potential DC generator. Energizing the electrodes releases Al3+ at the anode and OH- and hydrogen at the cathode, facilitating the electrocoagulation-flotation process. Qualitative analysis indicates an increase in floating foam with treatment time and electrolyte conductivity. The system's performance was evaluated by monitoring parameters such as turbidity, pH, conductivity, and oxidizability, demonstrating a significant reduction in suspended and organic matter. Treatment with NaCl and CaCl2 electrolytes resulted in removal efficiencies of 94% and 88% for turbidity, and 58.92% and 75% for organic matter, respectively. These results were confirmed by analyzing the IR spectra of the sludge post-treatment. This integrated approach shows promise for effective surface water treatment, offering potential for practical application in drinking water production systems.

This exploration chiefly examines the equilibrium solubility and the dissolution thermodynamics of glycine in aqueous solutions containing ammonium chloride and ammonium sulphate. The solubilities were examined from 288.15 K to 308.15 K temperatures engaging analytical gravimetric method. Salting-in or salting-out effects serves as principal factors for the disparity of solubilities in the electrolytic medium. The obtained solubilities were employed to estimate the thermochemical features of the investigational mixtures. Afterwards, calculations of the free energies, associated with solvation and various thermochemical properties within the aqueous electrolytic environment were also done. Also, this study explicated various non-covalent interactions including the solubility and stability of amino acid, by considering short-range interactions such as solute–solvent, solvent–solvent, and acid–base interactions. The present work reveals that the physical properties of aforementioned electrolytes and the size of the glycine are the main factors for the variation of thermochemical properties. The study provides detail about the molecular interactions and energetics that govern the solubility behaviour of amino acids in diverse environments.

SiO2 is considered a promising candidate for future high-power energy Li-ion batteries thanks to its affordability and accessibility, low discharge potential (0.7 V vs. Li+/Li), and high specific capacity of 1965 mAh g-1. Rice husk naturally contains SiO2 in the form of nanoparticles, making it a reasonably priced anode material with a high silica content. In this study, amorphous and porous SiO2/C anode materials are successfully synthesized by calcinating rice husk with NaOH, an activating agent. The prepared anode materials exhibited a surface area of 210 m2 g-1 with pore sizes ranging from 50 to 100 nm. In addition, SiO2 particles were coated by a 3-5 nm carbon layer to depress volume expansion and thus enhance cycling performance. The SiO2/C anode provided a capacity of 1625.3 mAh g-1 in the 1st cycle and maintained around 645 mAh g-1 in the following 50 cycles. The optimal negative/positive capacity ratios were determined in coin cells and the high-capacity pouch cells (4x6 cm2, 40 mAh) were further assembled to demonstrate a potential application of SiO2/C in high-power Li-ion batteries.

This paper analyzes the computational aspects of a planar non-fullerene acceptor, specifically indenoindene (IDTIC-4F), in the context of organic solar cell production. The B3LYP/6-31G(d,p) and TD-B3LYP/6-31G(d,p) methods are identified for predicting optoelectronic properties, with calculations comparing HOMO and LUMO energies, Egap, λmax to experimental results. Illustrative techniques, including TDM, RDG, ELF analysis, and hole/electron isosurface, depict electronic excitation processes and electron-hole positioning. The study evaluates IDTIC-4F as an electron donor alongside fullerenes and their derivatives, revealing varied Voc values (0.754 to 1.254 V). Emphasizing IDTIC-4F's substantial potential, the research suggests its promising viability as an electron donor for solar cell integration

This paper describes a comparative study concerning the molecule 1-methyl-2-[(E)-2-(4-methylphenyl) ethenyl]-4-nitro-1H-imidazole (EMENI). The study involved experimental analysis using high-resolution X-ray diffraction and DFT calculations using the B3LYP functional, along with the 6–311G(d,p) basis set. An accurate depiction of the molecular electron charge density distribution in the compound was achieved using Hansen and Coppens' multipolar model. The study also involved a topological analysis of the total electron density and the location of critical points of the bond, which helps in evaluating the molecular reactivity. Additionally, Hirshfeld surface (HS) and reduced density gradient (RDG) analyses were conducted to explore the specific intermolecular interactions responsible for the stiffness of the molecular arrangement in the compound's packaging. The analyses revealed that H...H interactions significantly influenced the intermolecular contacts, comprising 34.3% of the total interactions as indicated by the 2D fingerprint plots. Furthermore, the study included an exploration of charge transfer and establishment of the electronic characteristics of EMENI through Frontier molecular orbitals (FMO) analysis and HOMO-LUMO energies. Finally, the current study involved an in-silico investigation using molecular docking to evaluate the biological activity of the compound studied. This investigation showed that the title compound exhibits exceptional antiprotozoal activity against Trichomonas

The present study aims to identify effective bioactive compounds from Caralluma europaea as potential inhibitors of EGFR. Five Caralluma europaea compounds previously evaluated for their ability to inhibit cell proliferation were tested against EGFR and compared to the industry standard inhibitor Erlotinib. In this instance, these derivatives were focused on docking studies, which discovered the specific interactions of the identified phytocompounds with EGFR. Three phytocompounds (Hesperetin, Quercetin, and Myricetin) were shown to have the highest total scores and the best energies (lowest energy level) among compounds coming from the contribution of several interactions with EGFR. These three phytochemical compounds may have a greater inhibitory potential for the EGFR than the reference control, Erlotinib. Thus, Hesperetin was able to dock deeply within the EGFR binding region, resulting in a favorable binding interaction as well as improved total scores and docking energies, which were crucial in stabilizing the docking complex conformation. The results showed that Hesperetin had an excellent ADMET profile. The current findings forecast that the natural compound Hesperetin could be a better drug candidate for pancreatic cancer and non-small cell lung cancer, and further in vitro and in vivo studies may demonstrate its therapeutic potential.

In this project, we modified the biochar adsorbent using iron oxide nanoparticles coated with humic acid to remove methylene blue, a cationic dye. The prepared adsorbent was characterized using various analytical techniques, including Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller surface area measurement (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The magnetic properties were determined using a vibrating sample magnetometer (VSM). Surface adsorption experiments were conducted to investigate the factors influencing the surface adsorption of methylene blue by the prepared biochar adsorbent in aqueous environments. Various parameters such as solution pH, contact time, adsorbent dosage, and initial dye concentration, were examined. The results of surface adsorption analysis at different concentration revealed that the adsorption behavior on the adsorbent could be accurately described by the Langmuir isotherm and the elovich kinetic equation. The isotherm parameters for surface adsorption were also determined.

Within the present work the adsorption behavior of hydroxychloroquine drug onto B24N24 nanocage, and doped B24N24 nanocage with Si aend Al have been investigated by B3LYP density functional at the 6-31G (d, p) level. To improve the interaction strength drug adsorption on the B24N24 nanocage, substituted a boron atom with aluminum and silicon. The electronic and geometric virtues in terms of adsorption arrangement, frontier molecular orbitals, adsorption energy, gap energy, chemical hardness, dipole moment, chemical potential, and density of state (DOS) and the quantum theory of atom in the molecule (QTAIM) analyses are calculated. Results showed that the negative absorption energy incrased and the electronic properties of Al-doped BN were improved for drug absorption. Therefore, the study of the drug release mechanism is indicating that in the low pH of the cells the tendency of the drug to release in the target cells increases.

Renewable energy, like solar energy, has become a viable solution to the scarcity, environmental degradation and greenhouse effects associated with fossil fuels. Many techno-industries are now developing reliable and affordable sustainable energy technology to convert sunlight into electricity and reduce greenhouse gas emissions and nuclear by-products. In this research, eight metal-free organic phenothiazine and phenoxazine-based dyes of the D-A-π-A architecture were studied theoretically using DFT and TD-DFT techniques for usage as dye-sensitized solar cells (DSSCs). The effects of π-spacers on the structural, electrical, photovoltaic, and optical characteristics of the designed dyes were examined. The results showed that PO dyes have lower band gaps (ΔEg) than PZ dyes, which means 2-[3-(10H-phenoxazin-3-yl)furan-2-yl]-10H-phenoxazine pushed electrons towards the acceptor unit readily than 2-[3-(10H-phenothiazin-3-yl)furan-2-yl]-10H-phenothiazine. And that thieno[3,4-b]pyrazine contributed to the lowering of band gaps (ΔEg) than thieno[3,2-b]thiophene, thus, enhancing the photoelectronic properties of the dyes. The band gaps ΔEg of the dyes ranged from 1.48 to 1.88 eV; Open-circuit voltage (V_OC) values ranged from 0.60 to 0.98 eV and light-harvesting efficiency (LHE) values from 0.6583 to 0.9444. Molecular, optical, and most photovoltaic parameters supported PODB, POTB and PZDT dyes as most suitable candidate for DSSC application.

In this work, we tested the effectiveness of phenyl-1-propylquinoxaline-2(1H)-one (PRQX), a novel quinoxaline analogue, as a corrosion inhibitor for carbon steel (C-S) in a 1M HCl electrolyte. Incorporating numerous techniques, such as scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy, we examined the inhibitory properties of PRQX. PRQX maximum anti-corrosion efficiency was determined to be 97.7% at 10-3 M dose at 303 K temperature. PRQX displayed a mixed-type inhibitor effect, slowing anodic and cathodic corrosion processes, as indicated by PPD tests. The PRQX molecule binds to the C-S surface in compatibility with the Langmuir adsorption model. Uv-visible analysis of the inhibited electrolyte clearly reveals the complexation of the Fe2+ with the PRQX molecule. Additionally, using density functional theory (DFT) and molecular dynamics simulation (MDS), conceptual analysis of the PRQX molecule's most reactive sites and its adsorption process were carried out.

Brown seaweed is a biosorbent for textile dyes from industrial effluent, but the presence of pigments and particle size restricts its adsorption capabilities and kinetics. Here, we fabricated seaweed Sargassum wightii as carbonated ash (SWCA) for cationic (methylene blue (MB), crystal violet (CV), safranin (SAF)) and anionic dyes (congo red (CR)). Biosorbent SWCA contains hydroxyl, primary amines, carboxyl, OH, C-O, C≡C-H, C=C, C-C≡C, C-N, N-H, and other functional groups. The pyrolysis process transformed the several types of oxygen in the seaweed waste into carbon-oxygen single bonds, which functioned as a bonding chain. The X-ray diffraction (XRD) spectra of SWCA diffractograms show that the structure is crystalline. As the calcite peak grows stronger, the Ca (OH)Cl peaks become weaker. The scanning electron microscope (SEM) image showed that organic carbonization caused SWCA pores. Strong energy dispersion x-ray (EDX) signals for C, O, Na, S, Cl, K, and Ca indicate SWCA has been carbonized. This investigation showed that when the concentration of SWCA was increased from 0.5 to 2 g/L, the quantity of MB, CV, SAF, and CR adsorbed dyes decreased significantly.

This study investigates the catalytic potential of five recently synthesised symmetrical azine ligands in combination with various metal salts in situ for the synthesis of phenoxazinone synthase. UV spectrometry was used to analyse the resulting complexes, all of which exhibited remarkable efficiency in catalysing the oxidation of aminophenol to phenoxazinone under ambient conditions. In particular, the pairing of the ligand L1 and CuCl2 in a 1:1 molar ratio ([1L/1M]) showed the highest catalytic performance. These results offer promising prospects for the application of these complexes as effective catalysts in various chemical processes. Furthermore, a Density Functional Theory investigation of the chemical reactivity of these ligands was carried out to determine various widely recognised quantum chemical descriptors, including hardness, chemical potential, electrophilicity indices and molecular orbital theory analysis. The study aimed to characterise nucleophilic, electrophilic, electron accepting and electron donating compounds.

This work aimed to study the temperature dependant solubility of sulfasalazine (Sulf) in binary solutions of polyethylene glycol (PEG) 600 and 1,2, propanediol using the saturation shake flask method between 298.15 K and 313.15 K. Generally, sulf solubility increased with the elevation of temperature and mass fraction of the co-solvent. The highest drug solubility was observed in pure PEG-600 (56.67 ×10-3 mol L-1) while the lowest drug solubility was observed in pure water (0.14 ×10-3 mol L-1). Drug solubility in pure 1,2 propanediol was 3.56 ×10-3 mol L-1. The same results were observed at each temperature. Thermodynamic analysis indicates endothermic solubilization in aqueous mixtures in each of the investigated binary solvent mixtures. Overall, the findings of this work suggest that the various co-solvents could be used to solubilize poorly water-soluble drugs such as Sulf. The experimental solubility data of Sulf were regressed using the van’t, the mixture response surface, the Jouyban-Acree, the Jouyban-Acree-van’t Hoff, and the modified Wilson models.

In this study, an optimized QuEChERS method combined with ultra-high-performance liquid chromatography (UHPLC) was employed to quantify residue levels. The amount of diazinon pesticide in peach and cherry samples at days after use with the permitted dose of 25 g was 1.66 mg/kg for peach samples and 1.82 mg/kg for cherry samples. The first-order kinetic model describes the loss patterns in all products, with half-lives of 1.8 days for the peach samples and 1.9 days for the cherry samples. Method validation was achieved based on the recovery percentage values obtained from the samples for inter-day repeatability RSDs% (n=21) for peach samples 13.2% and cherry samples 15.6%. The method validation was obtained recovery values from the samples for intera-day repeatability RSDs% (n=7) was achieved based on the 92.5–106.2% recovery for the peach samples with RSD ≤7.1%, and was achieved based on the 92.0–102.0% recovery for cherry samples with RSD ≤5.2%. The proposed UHPLC method could selectively separate diazinon pesticides from peach, and cherry samples. Furthermore, the method in this research employed can be adapted for studying other pesticide compounds with low concentrations in fruits, water, and soil, highlighting the versatility of the method employed.

Tributyltin is well recognized as an environmental endocrine disruptor and is listed as a priority substance that requires extended monitoring by the European Water Framework Directive (2000/60/EC). At the same time, due to their high pathogenicity, producing hormonal, immune, metabolic and reproductive dysfunctions, other butyltin species (e.g. monobutyltin, dibutyltin and tetrabutyltin) are consistently monitored in marine and freshwater aquatic ecosystems; the European Chemicals Agency classified these butyltin species as potential carcinogens and toxic substances for the human reproduction. Several analytical techniques, including gas chromatography and high-performance liquid chromatography, have been used to determine organotin species in aquatic ecosystems. Because of their chemical properties, organotin compounds result poorly stable upon temperature and are thus unsuited for direct analysis through capillary gas chromatography, which is usually performed after a derivatization step. The procedure described in this paper allowed the detection of underivatized chlorinated organotin compounds through gas chromatography-triple quadrupole mass spectrometry. Importantly, the obtained spectra of chlorinated monobutyltin and dibutyltin are herein presented and the fragmentation patterns are identified for the first time. The method was successfully applied to evaluate organotin compounds in sediments, providing the speciation of organotin species. Taking advantage of a simplified procedure of sample treatment, this study provided an innovative protocol for the gas chromatography/mass spectrometry of phenyl and butyl-substituted organotin compounds in contaminated sediments, capable of improving the efficiency of the conventional analysis of organotin compounds.

Pesticides serve a crucial function in contemporary farming practices, safeguarding agricultural crops against pest infestations and boosting production outputs. However, indiscriminate use has caused environmental and human health damage. The aim of this study was to develop and validate a gas chromatography-flame ionization detection (GC-FID) methodology for the direct and routine analysis of spiromesifen residues in soil, leaves and tomato fruits. The proposed method prioritizes simplicity by avoiding derivatization steps, offering advantages over existing approaches that utilize lengthy multi-step extraction or derivatization prior to GC analysis. A key novelty of this work is the development of a QuEChERS extraction coupled directly to GC-FID without further clean-up or chemical treatment steps, rendering the method more convenient and accessible for routine monitoring applications. Factors evaluated included: sample solvent; inlet and column temperature profiles; inlet type; sample volume; and injection technique. Recovery and matrix effect studies were conducted by fortifying tomato, leaf, and soil matrices at three different concentrations (0.5, 1, and 10 µg/mL). Quadruplicate analyses (n=4) yielded mean recoveries of 98.74% (fruits), 93.92% (leaves), and 94.18% (soil), confirming efficient extraction. Matrix effects were negligible at -7.9%, -7.8% and -5.3%, respectively. Chromatographic linearity of developed GC-FID method was excellent over the 0.002-20 µg/mL range with R2 > 0.9979. The method demonstrated good precision, with inter- and intra-day RSD% ranging from 0.06-1.8%, below the 3% limit. GC-MS analysis confirmed spiromesifen identification. Under greenhouse conditions, residual levels were 1.39 mg/kg in soil, 8.24 mg/kg in tomato, and 3.39 mg/kg in leaves.