Tailoring Physicochemical Properties of V2O5 Nanostructures: Influence of Solvent Type in Sol-Gel Synthesis.

The influence of different solvents, including aqueous and nonaqueous types, on the physicochemical properties of V2O5 nanostructures was thoroughly investigated. Various characterization techniques, such as XRD, XPS, FTIR, Raman spectroscopy, UV-vis DRS, SEM, TEM, and BET, were employed to analyze the obtained materials. Additionally, the adsorption properties of the synthesized V2O5 nanostructures for methylene blue were examined, and kinetic parameters of adsorption were calculated. The results demonstrate that the morphology of the obtained crystals can be finely controlled by manipulating water concentration in the solution, showcasing its profound impact on both the structural characteristics and adsorption properties of the nanostructures. Furthermore, the structural changes of the resulting V2O5 material induced by solvents show strong impacts on its photocatalytic properties, making it a promising photocatalyst.

Laser-Treated MXene as an Electrochemical Agent to Boost Properties of Semitransparent Photoelectrode Based on Titania Nanotubes.

In this study, Ti3C2Tx underwent laser treatment to reshape it, resulting in the formation of a TiO2/Ti3C2Tx heterojunction. The interaction with laser light induced the formation of spherical TiO2 composed of an anatase-rutile phase on the Ti3C2Tx surface. Such a heterostructure was loaded over a titania nanotube (TNT) layer, and the surface area was enhanced through immersion in a TiCl4 solution followed by thermal treatment. Consequently, the photon-to-electron conversion efficiency exhibits a 10-fold increase as compared to bare TNT. Moreover, for the sample produced with optimized conditions, five times higher photoactivity is observed in comparison to bare TNT. It was shown that under visible light irradiation the most photoactive heterojunction based on the tubular layer reveals a substantial drop in the charge transfer resistance of about 32% with respect to the dark condition. This can be attributed to the narrower band gaps of the modified material and improvement of the separation efficiency of the photogenerated electron-hole pairs. Overall results suggest that this investigation underscores TiO2/Ti3C2Tx as a promising noble-metal-free material that enhances both the electrochemical and photoelectrochemical performances of electrode materials based on TNT that can be further used in light-harvesting applications.

Separation of non-racemic mixtures of enantiomers by achiral chromatography.

The phenomenon of partial separation of enantiomeric mixtures in achiral chromatography (ACh) has already been documented for a wide variety of chiral compounds. It is attributed to the so-called effect of self-disproportionation of enantiomers (SDE). However, quantitative description of the SDE mechanism underlying adsorption of enantiomers on achiral surfaces is still incomplete, which hinders the application of that technique for large-scale separations. In this study, a mechanistic model for description of retention behavior of SDE-phoric compounds in silica-based ACh has been developed along with a procedure for fast determination of the model parameters. The model assumes formation of associates of chiral molecules, which occurs due to homo and hetero-chiral interactions in the adsorbed phase. The ability of the model to reproduce band profiles was verified for enantiomeric mixtures of three structurally different chiral compounds.

Removal of Phosphorus with the Use of Marl and Travertine and Their Thermally Modified Forms-Factors Affecting the Sorption Capacity of Materials and the Kinetics of the Sorption Process.

The paper presents new reactive materials, namely marl and travertine, and their thermal modifications and the Polonite® material, analyzing their phosphorus removal from water and wastewater by sorption. Based on the experimental data, an analysis of the factors influencing the sorption capacity of the materials, such as the material dose, pH of the initial solution, process temperature, surface structure, and morphology, was performed. Adsorption isotherms and maximum sorption capacities were determined with the use of the Langmuir, Freundlich, Langmuir-Freundlich, Tóth, Radke-Praunitz, and Marczewski-Jaroniec models. The kinetics of the phosphorus sorption process of the tested materials were described using reversible and irreversible pseudo-first order, pseudo-second order, and mixed models. The natural materials were the most sensitive to changes in the process conditions, such as temperature and pH. The thermal treatment process stabilizes the marl and travertine towards materials with a more homogeneous surface in terms of energy and structure. The fitted models of the adsorption isotherms and kinetic models allowed for an indication of a possible phosphorus-binding mechanism, as well as the maximum amount of this element that can be retained on the materials' surface under given conditions-raw marl (43.89 mg P/g), raw travertine (140.48 mg P/g), heated marl (80.44 mg P/g), heated travertine (282.34 mg P/g), and Polonite® (54.33 mg P/g).

Viscosity Approximation of PDMS Using Weibull Function.

The viscosity of a fluid is one of its basic physico-chemical properties. The modelling of this property as a function of temperature has been the subject of intensive studies. The knowledge of how viscosity and temperature variation are related is particularly important for applications that use the intrinsic friction of fluids to dissipate energy, for example viscous torsional vibration dampers using high viscosity poly(dimethylsiloxane) as a damping factor. This article presents a new method for approximating the dynamic viscosity of poly(dimethylsiloxane). It is based on the three-parameter Weibull function that far better reflects the relationship between viscosity and temperature compared with the models used so far. Accurate mapping of dynamic viscosity is vitally important from the point of view of the construction of viscous dampers, as it allows for accurate estimation of their efficiency in the energy dissipation process.

Hydrophobic UV-Curable Powder Clear Coatings: Study on the Synthesis of New Crosslinking Agents Based on Raw Materials Derived from Renewable Sources.

Methods for the synthesis of urethane acrylates used as new crosslinking agents for hydrophobic UV-curable powder clear coatings were developed. In the synthesis of urethane acrylates, isophorone diisocyanate, glycerin, xylitol, polyethylene glycol and polysiloxane KF-6000, as well as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, were used. In order to increase the functionality of urethane acrylates, glycerin and xylitol derived from renewable sources were introduced. The chemical structure of the urethane acrylates was verified by IR spectroscopy. UV-curable powder clear coatings were obtained through a combination of urethane acrylates with unsaturated polyester resins. The thermal behavior and crosslinking density were examined using DMA. The obtained coatings were evaluated by performing the following tests: roughness, gloss, scratch resistance, hardness, adhesion to steel and water contact angle. As part of this research, high hydrophobicity and scratch resistance of UV-curable powder clear coatings were developed, which are a VOC-free and economically attractive alternative method for low thermal resistance surface protection, such as for composites, wood and wood-based materials.