Aqueous Solution Research Articles

Nickel Nanoparticles as a Sustainable Catalyst for the Synthesis of 2H‐Pyran Derivatives under Microwave Irradiation, and their Anti‐Inflammatory Activity

AbstractThis study includes an environmentally and effectively green method for the synthesis of novel 2H‐pyran derivatives 4 a–h via a one‐pot reaction of different aromatic aldehydes 1 a–h with ethyl cyanoacetate (2) and 2‐acetylphenyl‐4‐tolylsulfonate (3) in the presence of nickel oxide nanoparticles (NiO NPs) as a green catalyst in an aqueous mixed solution (EtOH: H2O, 1 : 3 ratio) using microwave irradiation. The structure of all prouducts were confirmed by spectral data and elemental analysis. All compounds were investigated for anti‐inflammatory activity compared with celecoxib as a reference drug. The obtained results indicate that 2‐[4‐(4‐tosyl oxy phenyl)‐3‐cyano‐2‐oxo‐2H‐pyran‐6‐yl]phenyl 4‐tolylsulfonate (4 b) is the most anti‐inflammatory effective, which showed after 5 h., significantly inhibited inflammation compared with the carrageenan alone group (P < 0.0001)., and when compared to the treated group with celecoxib, inflammation was inhibited 42.38 % for compound 4 b compared to celecoxib 48.39 % simultaneously. Moreover, its histopathological examination was studied and showed a significant attenuation of inflammation and edema. The results indicated that pyran derivatives could serve as promising lead compounds for further optimization as anti‐inflammatory agents.The present protocol offers several advantages, such as inexpensive, easy work, pure products, shorter reaction times, excellent yields, environmental friendliness, and easy reuse of the catalyst several times.

Stretchable supramolecular hydrogel with instantaneous self-healing for electromagnetic interference shielding control and sensing

Conductive hydrogels possess instantaneous self-healing and adhesive properties have generated great excitement in the fields of sensing and electromagnetic interference (EMI) shielding. In this study, we ingeniously designed hydrogel-based soft materials with high conductivity by using poly(vinyl alcohol) (PVA), positively charged Ti3C2Tx MXene and thioctic acid (TA) as source materials. Through concentration-induced ring-opening polymerization of TA monomers in an aqueous solution of potassium hydroxide (KOH), supramolecular poly(potassium thioctate) (poly(PT)) was obtained. Then, the multifunctional poly(PT)/PVA/p-MXene hydrogel with exceptional stretchability, substrate-adhesion and self-healing capability was achieved through abundant dynamic bonds, including disulfide bonds, hydrogen bonds, coordination bonds and electrostatic interactions. The hydrophobic main chains within poly(PT) provide robust protection against the oxidative degradation of MXene. This hydrogel shows outstanding strain sensing and extraordinary EMI shielding effectiveness (SE) of 48.56 dB caused by the inner structure, conductivity, and water content. Interestingly, the EMI SE can be regulated by reabsorbing moisture from the air, thereby enabling the reuse of dried hydrogel. Furthermore, the EMI SE can be dynamically modulated through controlled deformations, confirming the potential application for electromagnetic waves (EMWs) sensing. This innovative approach not only simplifies the fabrication of multifunctional materials but also expands the applications of adhesive hydrogels with conductivity.

A highly efficient and environmentally friendly approach to utilizing Quercus suber pericarp subfractions to remove metallic cations from aqueous solutions

Increasing water contamination from metal cations is a significant environmental challenge for humans. This has sparked extensive research into the development of adsorbents with superior removal efficiencies. This study assessed the adsorption capacity of crude and lignocellulosic fractions obtained from the pericarp of Quercus suber acorns, specifically focusing on the removal of Pb(II), Cd(II), Ni(II), and Cu(II) ions from aqueous solutions. The lignocellulosic fraction was separated from the crude fraction after extraction of cell wall polysaccharides using water and alkaline solutions. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the crude and lignocellulosic fractions. Data from equilibrium adsorption experiments were analyzed using the Langmuir and Freundlich isotherm models. The study found that the lignocellulosic fraction removed Pb(II) ions more efficiently than the crude fraction, with qmax values of 500.0 mg.g−1. Crude fractions exhibited a considerable retention potential for Cd(II), Ni(II), and Cu(II) ions with qmax values of 95.2 mg.g−1, 333.3 mg.g−1 and 200 mg.g−1 respectively. Crude and lignocellulosic fractions extracted from the acorn Q. suber pericarps could be environmentally friendly biosorbents for the removal of metal cations from aqueous solutions.

Toward Reliable Conformational Energies of Amino Acids and Dipeptides─The DipCONFS Benchmark and DipCONL Datasets.

Simulating peptides and proteins is becoming increasingly important, leading to a growing need for efficient computational methods. These are typically semiempirical quantum mechanical (SQM) methods, force fields (FFs), or machine-learned interatomic potentials (MLIPs), all of which require a large amount of accurate data for robust training and evaluation. To assess potential reference methods and complement the available data, we introduce two sets, DipCONFL and DipCONFS, which cover large parts of the conformational space of 17 amino acids and their 289 possible dipeptides in aqueous solution. The conformers were selected from the exhaustive PeptideCS dataset by Andris et al. [ J. Phys. Chem. B 2022, 126, 5949-5958]. The structures, originally generated with GFN2-xTB, were reoptimized using the accurate r2SCAN-3c density functional theory (DFT) composite method including the implicit CPCM water solvation model. The DipCONFS benchmark set contains 918 conformers and is one of the largest sets with highly accurate coupled cluster conformational energies so far. It is employed to evaluate various DFT and wave function theory (WFT) methods, especially regarding whether they are accurate enough to be used as reliable reference methods for larger datasets intended for training and testing more approximated SQM, FF, and MLIP methods. The results reveal that the originally provided BP86-D3(BJ)/DGauss-DZVP conformational energies are not sufficiently accurate. Among the DFT methods tested as an alternative reference level, the revDSD-PBEP86-D4 double hybrid performs best with a mean absolute error (MAD) of 0.2 kcal mol-1 compared with the PNO-LCCSD(T)-F12b reference. The very efficient r2SCAN-3c composite method also shows excellent results, with an MAD of 0.3 kcal mol-1, similar to the best-tested hybrid ωB97M-D4. With these findings, we compiled the large DipCONFL set, which includes over 29,000 realistic conformers in solution with reasonably accurate r2SCAN-3c reference conformational energies, gradients, and further properties potentially relevant for training MLIP methods. This set, also in comparison to DipCONFS, is used to assess the performance of various SQM, FF, and MLIP methods robustly and can complement training sets for those.

Study on the effect of radiation-resistant resin on water radiolysis

In recent years, the use of radiation-resistant resins of polyimide and polyether ether ketone becomes increasing as vessels for irradiation and unsealed radioisotope experiments. However, in our radiolysis experiments, the possibility of interaction between radiolysis products of water and the resin was found, suggesting concerns that the resin may affect reactions in water in radiation fields. To clarify the interaction, dichromate (Cr2O72−) reduction and hydrogen peroxide (H2O2) formation in γ-radiolysis of water were compared with and without the resin. The Cr2O72− reduction amount in aqueous solution with the resin became larger than that without the resin at the same dose, indicating the promotion of Cr2O72− reduction by the resin. On the other hand, the H2O2 formation in pure water with and without an electron scavenger were almost independent of the presence of resin. These suggested the interaction between hydroxyl radical and the resin in contact with water in radiation fields.

Dissolution of EAF slag minerals in aqueous media: Effects of sonication on brownmillerite and gehlenite

The accumulation of electric arc furnace slag (EAFS) in landfills has been causing severe environmental problems. This study examines the dissolution properties of EAFS minerals, including brownmillerite and gehlenite, essential for their possible use in resource recovery. An investigation was conducted to compare the effects of sonication and stirring on mineral dissolution while also assessing the usage of citrate as a complexing agent for gehlenite. Synthetic brownmillerite and gehlenite minerals were dissolved in aqueous solutions at room temperature using a 1:100 g/ml ratio. The dissolved elements were measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), while zeta potential and X-ray Photoelectron Spectroscopy (XPS) were used to assess changes in surface chemistry. Brownmillerite had significant dissolution extents, with Al and Ca dissolving up to 16 % and 8 %, respectively, in contrast to gehlenite, which dissolved less than 2 % under similar conditions. Sonication significantly increased the dissolution of brownmillerite by up to 100 %, although its impact on gehlenite dissolution varied depending on the duration of time. Besides, adding citrate enhanced the leaching of Al and Ca from gehlenite by facilitating complexation. XPS data demonstrated differences in elemental ratios on brownmillerite and gehlenite surfaces affected by the method used and the presence of citrate. Lastly, the dissolution extents of Al and Ca from EAFS were up to 12 %, depending on time and mixing method, with a preference for sonication over stirring. In conclusion, this study showed that minerals in EAFS have distinct dissolution characteristics, and sonication and citrate can considerably enhance dissolution

Synthesis, characterization, and kinetic approach of a polyvinyl chloride embedded-thiosemicarbazide sequestering agent for efficient uranium adsorption from aqueous solution

A new promising polyvinyl chloride embedded-thiosemicarbazide sequestering agent (PVC-TSC), was exploited to separate U(VI) from its water solution. Specifications for PVC-TSC were carried out efficaciously using respective performances such as BET, TGA, 1H NMR, SEM-EDX, 13C NMR, FT-IR, XPS, and GC–MS analyses, which assure a satisfactory synthesis. Variables like initial pH, agitation duration, temperature, starting U(VI) concentration, PVC-TSC dosage, co-existing ions, and eluting agents have all been fine-tuned by experimental optimization. In conditions of 298 K, pH 4.5, 30 min of agitation, and 0.63 × 10−3 mol/L uranium ions, the maximal sorption competence of PVC-TSC is 30 mg/g. Based on the adsorption-distribution isotherm estimation, the experimental value of 30.12 mg/g is similar to the theoretical value that Freundlich came up with. However, Langmuir's value is higher and more in line with the practical data. Modeling of the U(VI) kinetics adsorption by PVC-TSC yielded a theoretical retaining capacity of 29.66 mg/g for first-order (PFO) modeling and 32.051 mg/g for second-order (PSO) modeling, as suggested by a hybrid PFO and PSO kinetic model. By taking into account the thermodynamical factors ΔS° (−0.063 kJ/mol.K), ΔH° (−16.2 kJ/mol), and ΔG°, the adsorption evolution was anticipated to be exothermic, spontaneous, and best performed at down temperatures. From a cost perspective, eluting the loaded PVC-TSC composite with 0.5 M H2SO4 yields a 90 % efficiency rate for U(VI) ions.

Synthesis and characterisation of visible light-responsive Fe-doped BiOCl NPs and their application for the remediation of textile dye by LED irradiation

ABSTRACT In the present research work, Fe-doped bismuth oxychloride (Fe-doped BiOCl) photocatalyst is synthesised through the precipitation technique, and the mineralisation of textile dye is investigated in the presence of light-emitting diode (LEDs) irradiation (400–700 nm). The prepared photocatalysts were characterised through various spectroscopic techniques for the detailed morphological, elemental and surface properties. The UV–vis absorbance maxima of Fe-doped BiOCl by UV-Vis was near 358 nm, while the band gap was 4.8 eV which is comparatively higher than the average value. Fourier transform infrared spectra showed typical bands of Fe doped BiOCl at 506 cm−1, 1601, 2337 and at 3565.0 cm−1. From the X-ray diffraction (XRD) pattern, the crystalline nature of the Fe-doped nanocomposite was confirmed whose calculated crystallite size was 41.12 nm. The major and sharp two theta peaks of XRD were at 11.95°, 24.07°, 25.81°, 32.46°, 33.39°, 36.47°. The microscopic technique showed that the size of the nanocomposite was 200–400 nm which was in the form of small nanosheets. The energy dispersive X-ray spectroscopy (EDS) showed peaks for Bi, O, Cl and Fe 36.91%, 26.48%, 36.37% and 0.24%, respectively, indicating the formation of the nanocomposite. The BET surface area of the Fe-doped BiOCl photocatalyst was 10.224 m2/g, while the pore volume was 0.065 cc/g. Further, the potential of the developed photocatalytic nanocomposite was evaluated for the photocatalytic degradation of the ethyl violet dye from the aqueous solutions. Various optimisation parameters have been discussed, and it has been found that 89% of the dye was degraded in 125 min with a 5.11 × 10−4 s−1 rate constant. The photocatalyst had shown excellent reusability and stability during the degradation of ethyl violet. The photocatalytic activity of Fe-doped BiOCl was compared with other photocatalysts and current literature and exhibited enhanced efficiency.

Adsorption of Fluoride Ions Using Si–Al–Mg Layered Double Hydroxides

ABSTRACT Removal of fluoride ions from water environments has become a research topic because high concentrations of fluoride ions in drinking water are harmful to the human body. The adsorption of fluoride ions by a Si – Al – Mg layered double hydroxide (LDH) was investigated in this study. The prepared adsorbent had a hydrotalcite-like LDH structure, which was decomposed by calcination and reconstructed upon contacting water. The adsorption process followed pseudo-second-order kinetics. Granulation of the adsorbent for application to chromatographic operation decreased the adsorption rate constant. Adsorption of fluoride ions was high at 7 < pHeq <10 and decreased at higher pHs. The adsorption mechanism involved ion exchange between the fluoride ions in aqueous solution and chloride ions in the adsorbent as well as physisorption via van der Waals forces. The adsorbent was selective towards fluoride ions over nitrate and sulfate ions, although the adsorption of fluoride ions was suppressed in the presence of chloride, carbonate, and phosphate ions. Chromatographic operation using the granulated adsorbent with an alumina-based binder was characterized by slow kinetics, necessitating a low flow rate for the feed solution. The prepared adsorbent was also used to selectively adsorb fluoride ions from simulated wastewater produced by the semiconductor manufacturing process.

Heat Capacity of Acetone and Its Aqueous Solutions at High Temperatures and Pressures

Heat Capacity of Acetone and Its Aqueous Solutions at High Temperatures and Pressures

Volume Effects in Interactions between L-Histidine and Pyridine Monocarboxylic Acid Isomers in an Aqueous Buffer Solution

Volume Effects in Interactions between L-Histidine and Pyridine Monocarboxylic Acid Isomers in an Aqueous Buffer Solution

Thermochemistry of the Dissolution of Copper Tetra-3-carboxyphtalocyanine in Aqueous Solutions of KOH at 298.15 K

Thermochemistry of the Dissolution of Copper Tetra-3-carboxyphtalocyanine in Aqueous Solutions of KOH at 298.15 K

Conductometric Properties and UV–Vis Spectroscopic Study of L-Glutamic Acid in Aqueous Solutions of L-Arabinose and D-Xylose in the Temperature Range of 293.15–313.15 K at Atmospheric Pressure

Conductometric Properties and UV–Vis Spectroscopic Study of L-Glutamic Acid in Aqueous Solutions of L-Arabinose and D-Xylose in the Temperature Range of 293.15–313.15 K at Atmospheric Pressure

Relationship between Coefficients of Activity and Dielectric Constants in Aqueous Solutions of Alkali Metal Fluorides

Relationship between Coefficients of Activity and Dielectric Constants in Aqueous Solutions of Alkali Metal Fluorides

Application of High-Resolution Infrared Thermography to Study the Effects of Technologically Processed Antibodies on the Near-Surface Layer of Aqueous Solutions

Application of High-Resolution Infrared Thermography to Study the Effects of Technologically Processed Antibodies on the Near-Surface Layer of Aqueous Solutions

Defect Engineering of Ultrasmall TiO2 Nanoparticles Enables Highly Efficient Photocatalysts for Solar H2 Production from Woody Biomass.

The conversion of woody biomass to H2 through photocatalysis provides a sustainable strategy to generate renewable hydrogen fuel but was limited by the slow decomposition rate of woody biomass. Here, we fabricate ultrasmall TiO2 nanoparticles with tunable concentration of oxygen vacancy defects (VO-TiO2) as highly efficient photocatalysts for photocatalytic conversion of woody biomass to H2. Owing to the positive role of oxygen vacancy in reducing energy barrier for the generation of •OH which was the critical species to oxidize woody biomass, the obtained VO-TiO2 achieves rapid photocatalytic conversion of α-cellulose and poplar wood chip to H2 in the presence of Pt nanoclusters as the cocatalyst. As expected, the highest H2 generation rate in α-cellulose and poplar wood chip system respectively achieve 1146 and 59 μmol h-1 g-1, and an apparent quantum yield of 4.89% at 380 nm was obtained in α-cellulose aqueous solution.

Evaluation of bubble column dehumidifier using magnesium chloride desiccant

With growing emphasis on indoor air quality and energy conservation, the development of sustainable and efficient dehumidification systems has become increasingly crucial across various industries. Liquid desiccant dehumidification system (LDDS) offers a more efficient alternative to conventional methods by utilizing low-grade waste heat. Most direct-contact liquid dehumidification systems use expensive desiccants such as LiCl and LiBr. Our research focuses on exploring MgCl2, prevalent in saltwater bitterns, as a cheaper, less toxic alternative. The core principle of this system involves passing air through a column filled with the MgCl2 aqueous solution, leveraging the hygroscopic properties of MgCl2 to remove moisture from the air stream effectively. Various parameters such as hole size, air flow rate and desiccant concentration are investigated. We further developed a numerical model for the dehumidification process considering the rise time of the bubbles in the desiccant solution and mass transfer in the bubble. After dehumidification, the diluted desiccant solution can be revived using low-grade heat. Use of seawater bitterns, with major component as MgCl2, shows potential for building an environmentally friendly and cost-effective dehumidification system.

The effect of Al and Zr content on corrosion of AlNiCoCuZr high-entropy alloys in a 5 wt% NaCl solution

High-entropy alloys are attractive structural materials for the design of apparatus for various chemical technologies due to their relative ease of production, corrosion resistance and high values of mechanical properties (hardness, strength). In the present work, the influence of aluminum and zirconium content on the corrosion resistance of Al(20−35)-Ni(5−15)-Co(15−30)-Cu(20−35)-Zr(5−40) high-entropy alloys was studied experimentally for the first time. Corrosion tests were performed in a 5 wt% NaCl aqueous solution during 1500 h at 298 K. It is established that the electronegative metals included in the alloy - Al and Zr are passivation components and with increasing their content in AlNiCoCuZr composition the corrosion rate in the studied conditions is decreased. It is shown that degradation of alloys occurs mainly as a result of nickel and cobalt hydroxide formation, the solubility of which is several orders of magnitude higher than that of aluminum hydroxide and zirconium hydroxide.

Synthesis, Surface Activity, Emulsifiability and Bactericidal Performance of Zwitterionic Tetrameric Surfactants

In this paper, a series of tetrameric surfactants (4CnSAZs, n = 12, 14, 16) endowed with zwitterionic characteristic were synthesized by a simple and convenient method and their structures were characterized by FT-IR, 1H NMR and elemental analysis. Their physicochemical properties were studied using the Wilhelmy plate method, fluorescence spectra and dynamic light scattering technique. 4CnSAZs have higher surface activities and tend to adsorb at the air/water surface rather than self-assembling in aqueous solution. The thermodynamic parameters obtained from surface tension measurements show that both processes of adsorption and micellization of 4CnSAZs are spontaneous and that the micellization processes of 4CnSAZs are entropy-driven processes. Both adsorption and micellization of 4CnSAZs are inclined to occur with the increase of alkyl chain length or temperature. For 4C12SAZs, there are only small-size aggregates (micelles), while the large aggregates (vesicles) are observed at the alkyl length of 4CnSAZs of 14 or 16. This shows that the alkyl chain length for oligomeric surfactants has a greater sensitivity for aggregate growth. The aggregate morphologies obtained from the calculated values of critical packing parameter (p) for 4C14SAZs and 4C16SAZs can be supported by the DLS measurement results. The test results obtained by the separation-water-time method show that 4CnSAZs have good emulsification performance and that the prepared emulsions appear to exit in the form of multiple emulsions. In addition, 4CnSAZs have good antibacterial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The present study reveals the unique behavior of a zwitterionic tetrameric surfactant and may give new insights into molecular design and synthesis of a high degree of surfactants with different structure characteristics for potential application in various industrial fields.

Fabrication of Kaolin Loaded Chitosan Hybrid Nanofibers for Recovery of Precious Palladium Cations from Aqueous Solution

Fabrication of Kaolin Loaded Chitosan Hybrid Nanofibers for Recovery of Precious Palladium Cations from Aqueous Solution