Properties Of Aqueous Solutions Research Articles

Synthesis and dilute aqueous solution properties of cationic antistatic surfactant functionalized with hydroxyl and ether groups

Abstract Polyester fibers tend to generate and accumulate electrical charges under friction and induction. This significantly affects the production and use process and even poses the risk of electric shocks and fire. Quaternary ammonium salt surfactants with a positive charge can be adsorbed on negatively charged polyester fibers and have excellent antistatic properties. Therefore, we have synthesised a cationic antistatic surfactant functionalised with hydroxyl and ether groups: N-hexadecyl-N,N-dimethyl-N-butanoxy glycerol ether ammonium chloride (HDBGA). The structure was characterized by 1H NMR, FTIR and ESI/MS. The excellent properties of HDBGA in aqueous solution were investigated by measuring the Krafft point (TK), surface tension, conductivity, and steady-state fluorescence. Also antistatic tests were carried out. The results show that the TK of HDBGA is below 0 °C indicating that it can still be applied in cold water. The new quaternary ammonium compound could effectively decrease the surface tension of aqueous solution to 31.28 mN m−1, where the critical micelle concentration (CMC) at 298.15 K was 3.83 × 10−4 mol L−1. In addition, the static electricity and static half-life values of the polyester cloths treated with the HDBGA solutions were also measured, as well as the effects on the fabric properties. The product exhibited excellent antistatic properties and satisfactory wash resistance, and the fabric fibers were not damaged.

Assessment of the robustness of MIL-88A in an aqueous solution: Experimental and DFT investigations

The stability of metal organic frameworks (MOFs) in a water-rich environment is a topic of significant importance, especially for adsorption and water purification applications. MIL-88A containing iron ions and fumaric acid ligands, was synthesized through a water-based viable strategy. The robustness of MIL-88A in aqueous solutions was studied experimentally, through evaluating the chemical, thermal, and hydrolytic stability of this compound by varying the conditions and properties of aqueous solutions. Different characterization techniques were employed to explore the features of the synthesized MIL-88A such as XRD, SEM, FTIR, TGA, UV–vis DRS, zeta potential, and MP-AES measurements. The electronic structure was studied on a model nanocrystal with density functional theory (DFT) calculations. The MIL-88A structure was drastically affected in basic medium as confirmed by the characterization techniques used. MIL-88A became completely amorphous upon exposure to boiling water. The hydrolytic stability results showed that MIL-88A loses gradually its structural integrity in each water cycle.

Tribological properties of bis(2-hydroxyethyl)ammonium oleate in glycerol and polyethylene glycol aqueous solutions

The use of eco-friendly water-based lubricants can benefit manufacturing processes and the health of operating personnel while reducing environmental pollution. This study investigates the tribological properties of bis(2-hydroxyethyl)ammonium oleate protic ionic liquid (PIL) as a potential additive to enhance tribological properties in aqueous solutions of glycerol and polyethylene glycol. The studied concentration of bis(2-hydroxyethyl)ammonium oleate was in the range of 0.1 to 1.5 wt%. The base fluids contained 50 wt% glycerol and 12 wt% polyethylene glycol, respectively. The physicochemical properties, wettability, and corrosion-prevention ability were evaluated. Lubricity was investigated using a ball-on-plate configuration in reciprocation mode and a four-ball tribometre. The wear scars were analysed using optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The introduction of PIL into the base fluids enhanced their wettability and ability to prevent corrosion. Furthermore, the PIL improved the wear and reduced the friction coefficient of both fluids. Moreover, their load-carrying ability was enhanced. Based on the observed results, friction and wear reduction mechanisms were suggested.

THE NATURE AND CONDITIONS OF FORMATION OF THERMOELECTRIC PROPERTIES IN NATURAL AND ARTIFICIAL LAYERED ALUMOSILICATES

The review analyzes the physical and che­mi­cal properties of modified natural and artificial layered aluminosilicates, which form the basis for the emergence of thermoelectric properties in materials based on them. It represented the main methods of modification and analysis of structural and thermoelectric properties of these materials. Chemical modi­fication of layered aluminosilicates is carried out by the reaction of solid aluminosilicate with concentrated aqueous solutions of metal hydroxides of groups I and II, their silicates, or phosphoric acid. The products of such interaction are called geopolymer. This name used to describe the reaction of the transformation of amorphous aluminosilicate into crystalline products during the interaction the solid pro­duct with concentrated alkali solutions of me­tals from the groups I and II, or the formation of composites and gel systems. The change in particle size, acidity of the media and impurity exchangeable cations in layered aluminosilicates significantly affects its acid-base and catalytic properties in aqueous solutions. The use of aqueous solutions increases the effect of hydrolytic processes on the number of hydroxide groups in the composition of the mineral, which are responsible for the adsorption pro­perties and create the possibility of oxidative-destructive catalysis with the participation of the mineral. The ion-exchange capacity of layered aluminosilicates depends on the degree of their dispersion. The increasing degree of the Perdispersion level increases the ion-exchange capacity of the material. It is also possible to modify layered aluminosilicates with phosphoric acid, which can form polymers. Using phosphoric acid allows high temperatures over 900 C to change the electrical properties of minerals. The priority directions for strengthening the properties of heat-to-electricity conversion through the development of composite materials based on layered aluminosilicates using metal nanoparticles, silicon carbide, carbon, graphene, graphene-like materials, and metal oxides embedded in the aluminosilicate matrix have been established.

2-Butanol Aqueous Solutions: A Combined Molecular Dynamics and Small/Wide-Angle X-ray Scattering Study

Structural properties of 2-butanol aqueous solutions at different concentrations have been studied using small- and wide-angle X-ray scattering and molecular dynamics simulations. The experimental structure factors have been accurately reproduced by the simulations, allowing one to explain their variation with concentration and to achieve a detailed description of the structural and dynamic properties of the studied systems. The analysis of experimental and computational data has shown that 2-butanol, the simplest aliphatic chiral alcohol, tends to form aggregates at a concentration above 1 M, affecting also both the structural and dynamic properties of the solvent.

Hierarchical MXene/Polypyrrole-Decorated Carbon Nanofibers for Asymmetrical Capacitive Deionization

Membrane capacitive deionization (MCDI) has emerged as a promising electric-field-driven technology for brackish water desalination and specific salt or charged ion separation. The use of carbon-based or pseudocapacitive materials alone for MCDI usually suffers from the drawbacks of low desalination capacity and poor cycling stability due to their limited accessible adsorption sites and obstructed charge-carrier diffusion pathways. Therefore, developing a hybrid electrode material with multiple charge storage mechanisms and continuous electron/ion transport pathways that can synergistically improve its specific capacitance and cycling durability has currently become one of the most critical technical demands. Herein, we developed a novel hierarchically architectured hybrid electrode by first spinning MXene into polyacrylonitrile (PAN)-based carbon nanofibers (MCNFs) to obtain a highly conductive carbon nanocomposite framework. The excellent spatial support structure can effectively prevent the dense packing of Cl-- and DBS--doped polypyrrole (PPy) molecular chains during the following electrodeposition process, which not only ensures the efficient transport of electrons in the continuous hybrid carbon nanofibrous skeleton but also provides abundant accessible sites for ion adsorption and insertion. The obtained self-supporting membrane electrodes (MCNF@PPy+Cl- and MCNF@PPy+DBS-) have the advantages of outstanding specific capacitance (318.4 and 153.9 F/g, respectively), low charge transfer resistance (10.0 and 5.3 Ω, respectively), and excellent cycling performance (78% and 90% capacitance retention ratios, respectively, after 250 electrochemical cycles). Furthermore, the asymmetrical membrane electrodes showed a superior desalination capacity of 91.2 mg g-1 in 500 mg/L NaCl aqueous solution and obvious divalent ion (Ca2+, Mg2+) selective adsorption properties in high-salt water from the cooling towers of thermal power plants.

Simulation case studies of aqueous formate solution for geological carbon storage

Carbon storage in geologic formations has been considered an important technology that reduces the carbon intensity of industrial processes based on fossil fuels. Carbon capture and storage (CCS) conventionally uses carbon dioxide (CO2) as a carbon carrier. However, various shortcomings of the conventional CCS are related to the physical properties of CO2, such as low carbon density at low to moderate pressure, low mass density, low viscosity, immiscibility with water, and corrosivity. In particular, CO2 injection often results in inefficient use of pore space in the formation under geophysical heterogeneities.This paper presents case studies of using aqueous formate solution as carbon-bearing water for geological carbon storage. Properties of aqueous formate solutions were measured. Experimental results showed that the formate solubility in 102,600-ppm NaCl + CaCl2 brine ranged from 30 wt% to 35 wt% between 25 and 75 °C. Viscosities of 30 wt% formate solutions in the brine were approximately 12 cp at 25 °C, 5 cp at 50 °C, and 3 cp at 75 °C with Newtonian behavior.Numerical reservoir simulations were performed for an aquifer and an oil reservoir. Simulation results consistently showed that the formate injection case resulted in more stable fronts of oil and water displacement. The more stable fronts yielded the oil recovery and carbon storage that were insensitive to the injectant breakthrough. This is a substantial advantage of using formate as a carbon carrier for controlling the risk of CCS associated with the permeability heterogeneities and their impact on the subsurface flow regime.The case study of enhanced oil recovery and carbon storage in an oil reservoir showed that the net present value (NPV) of the formate injection case would be equivalent to that of the CO2 injection case when the cost of CO2 electrochemical reduction (ECR) into formate was $269/t-CO2 for year 20. The breakeven cost of CO2 ECR for the formate injection case was $575/t-CO2 for year 20. Although the estimated CO2 ECR costs are sensitive to many factors, they are not unrealistically higher than the current costs of CO2 ECR reported in the literature.

Application and Dyeing Process of Substantive Dye

This paper reports the studies available on the theory of substantive dye, the application properties of substantive dye and dye ability of fibers in relation to dye structure. Dyeing with substantive dyes and comparison with acid dyes; some properties of aqueous solutions of the substantive dyes; adsorption of substantive dyes from aqueous solution; distribution of a colloid between an interface and the distribution medium was discussed. The interaction between dye and fibre under given dyeing conditions was presented. Different researchers studied the process of dyeing with substantive or colloidal dyes and the factors which affect the dispersion and stability of the dye.

Ultrasonic Investigation of Thermodynamic and Electrochemical Properties of Aqueous Solutions of Ammonium Salts and Comparative Study Among the Chosen Salts

Ultrasonic Investigation of Thermodynamic and Electrochemical Properties of Aqueous Solutions of Ammonium Salts and Comparative Study Among the Chosen Salts

A New Force Field for OH- for Computing Thermodynamic and Transport Properties of H2 and O2 in Aqueous NaOH and KOH Solutions.

The thermophysical properties of aqueous electrolyte solutions are of interest for applications such as water electrolyzers and fuel cells. Molecular dynamics (MD) and continuous fractional component Monte Carlo (CFCMC) simulations are used to calculate densities, transport properties (i.e., self-diffusivities and dynamic viscosities), and solubilities of H2 and O2 in aqueous sodium and potassium hydroxide (NaOH and KOH) solutions for a wide electrolyte concentration range (0-8 mol/kg). Simulations are carried out for a temperature and pressure range of 298-353 K and 1-100 bar, respectively. The TIP4P/2005 water model is used in combination with a newly parametrized OH- force field for NaOH and KOH. The computed dynamic viscosities at 298 K for NaOH and KOH solutions are within 5% from the reported experimental data up to an electrolyte concentration of 6 mol/kg. For most of the thermodynamic conditions (especially at high concentrations, pressures, and temperatures) experimental data are largely lacking. We present an extensive collection of new data and engineering equations for H2 and O2 self-diffusivities and solubilities in NaOH and KOH solutions, which can be used for process design and optimization of efficient alkaline electrolyzers and fuel cells.

Structural and Optical Properties of Rhodamine Dye Aqueous Solutions and Thin Films

Structural and Optical Properties of Rhodamine Dye Aqueous Solutions and Thin Films

THE EFFECT OF MECHANOACTIVATION AND MICROWAVE EFFECTS ON THE SURFACE PROPERTIES OF WATER AND AQUEOUS SOLUTIONS

Most food mixtures, where the liquid acts as a dispersion medium, are formed with the participation of water and aqueous solutions,. The formation of stable surface interactions in disperse systems with the participation of water is based on overcoming the forces of surface tension at the interface between the phases. The aim of the research is to analyze the effect of mechanical activation during stirring and microwave exposure on the surface properties of water and aqueous solutions. The object of the research is distilled water, bottled “Berdovskaya taiga” drinking water, an aqueous solution of NaCl (3.33%), an aqueous solution of NaCl (3.33%) with the addition of 1% flour with stirring. The main research method is the method of capillary rise of liquid in a tube of small cross section, partially immersed in liquid. It has been established that both mechanical and electromagnetic effects change the surface energy of water and aqueous solutions. But their influence is ambiguous. Surface tension during mechanical activation by stirring decreases to a certain minimum for different time intervals for different solutions, and then increases to a certain level. The retention time of the reduced surface energy of distilled water after stirring at a frequency of 100 rpm is 60–80 s. There is a tendency for a noticeable effect of impurities on the surface tension. The more complex the solution and the higher the concentration of impurities, the lower its surface energy. According to the results of the research, for technological purposes, for example, dough kneading, it is recommended to mechanically process (mix) solutions for dough kneading for 60–70 s or microwave treatment for no more than 20 s.

Physical properties of aqueous solutions of 1-propanol near its pequliar point

The work is devoted do the investigation of ultrasound absorption in aqueous solutions of 1- and 2-propanols near their peculiar points. It is assumed that the anomalous ultrasound absorption is caused by the formation of unstable nuclei of a new phase. It is noted, that the concentrations xp(MLS) and xp(US), where the intensities of molecular light scattering and ultrasound absorption take their maxima respectively as well as the point where the concentration curves for differ temperatures intersect are close to each other. A theoretical model for the ultrasound absorption by a nucleus is constructed. The characteristic size of nucleus and the typical time decay for its radial vibrations are estimated. The behavior of the ultrasound absorption coefficient is analyzed on resonance frequencies (f∼10 MHz) and ones removed from them (f≫10MHz). All characteristic experimental peculiarities of the resonance and classic absorption are reproduced with satisfactory accuracy in the framework of the model proposed.

Interface-engineered molybdenum disulfide/porous graphene microfiber for high electrochemical energy storage

Fiber-shaped supercapacitors (F-SCs) have received great interests in future portable electronics and wearable industries due to their high charging capacity, exceptional weavability and long lifespan. However, the stacked micro/nano-structure and poor faradaic activity of fibrous electrode that severely restrict the ion dynamic transport and redox charge storage bring obstacles of low energy density and practical applications. Herein, we report a novel F-SCs electrode made of hierarchical-ordered molybdenum disulfide/porous graphene core-shell microfiber (MoS2/PGF). The MoS2/PGF exhibits highly conductive porous core, large electroactive shell, C-Mo chemical bonds bridge and interface-engineered structure, creating smooth channels and exposed surface for boosting ion kinetics and faradic charge transfer. Significantly, the MoS2/PGF presents high capacitance of 1093 mF cm−2 and steady cycling property in H3PO4 aqueous solution. Moreover, the MoS2/PGF assembled solid-state F-SCs show large energy density of 85.4 µWh cm−2, temperature-dependent stability and good bending capability. Given those outstanding advantages, the F-SCs can be integrated into flexible substrates to power wearable electronic devices, which will remarkably contribute to the development of new energy technology and carbon neutrality fields.

Measurement and correlation of thermodynamics properties of aqueous solutions containing glycols. Part II: Excess molar enthalpy

In this work, excess molar enthalpies of binary liquid mixtures of {water + ethanol, or + ethylene glycol, or + diethylene glycol, or + triethylene glycol, or + poly(ethylene glycol) 200, or + poly(ethylene glycol)300, or + poly(ethylene glycol)400, or + poly(ethylene glycol)600, or + glycerol} have been determined as a function of composition using a microcalorimeter Thermal Activity Monitor (2277, Thermometric) at 298.15 K and atmospheric pressure. The results were fitted by the Myers-Scott equation, as a function of mole fraction. The values of excess molar enthalpies were exothermic and large. The excess partial molar enthalpies and excess partial molar enthalpies at infinite dilution were calculated. Moreover, the experimental results were used to test the applicability of the Wilson, NRTL and UNIQUAC models. The results of excess molar enthalpies were discussed in terms of molecular interactions.

Study on vapor-liquid equilibrium and microscopic properties of DL-proline, L-glutamic acid, and L-serine aqueous solutions.

The vapor–liquid equilibrium (VLE) in aqueous amino acid solutions is essential in chemical production, such as purification, isolation, or crystallization of amino acid intermediates. In this work, VLE of DL-proline, L-glutamic acid, and L-serine aqueous solutions was measured at pressures ranging from 4.82 to 102.58 kPa. The developed model was successfully applied to correlate experimental data with temperatures in the range of 298.15–382.75 K. Model parameters (h, , , , and ) were given. Moreover, the amino acid aqueous solution was investigated by Fourier transform infrared spectroscopy (FTIR). By analyzing infrared spectra, the strength of intermolecular interactions was obtained, and the structure–activity relationship between the microscopic interactions and the VLE was established.

Novel Moringa oleifera Leaves 3D Porous Carbon-Based Electrode Material as a High-Performance EDLC Supercapacitor.

Biomass-based activated carbon has great potential in the use of its versatile 3D porous structures as an excellent electrode material in presenting high conductivity, large porosity, and outstanding stability for electrochemical energy storage devices. In this study, the electrode material develops through a novel consolidated carbon disc binder-free design, which was derived from Moringa oleifera leaves (MOLs) for electrochemical double-layer capacitor applications. The carbon discs are prepared in a series of treatments of precarbonized, chemical impregnation of zinc chloride, integrated pyrolysis of N2 carbonization, and CO2 physical activation. The physical activation temperatures applied at 650, 750, and 850 °C optimize the precursor potential. By optimizing the 3D hierarchical pore properties of the MOL750, the carbon disc binder-free design demonstrates optimal symmetric supercapacitor performance with a high specific capacitance of 307 F g–1 at a current density of 1 A g–1 in an aqueous electrolyte solution of 1 M H2SO4. Furthermore, the extremely low internal resistance (0.006Ω) of the carbon disc initiated excellent electrical conductivity. The supercapacitors also maintain their high capacitive properties in aqueous electrolyte solutions of 6 M KOH and 1 M Na2SO4, respectively. The results show that a novel consolidated carbon disc binder-free design can be obtained from biomass MOLs through a reasonable approach to develop superior electrode materials to enhance high-performance electrochemical energy storage devices.

Improving the antioxidant and anticancer potential of Cinnamomum cassia via fermentation with Lactobacillus plantarum

This study designed to investigate effect of fermentation by Lactobacillus plantarum on antioxidant and anticancer properties of Cinnamomum cassia aqueous solution. The optimum condition to produce high antioxidant activity was 107 CFU L. plantarum/10 g cinnamon at pH6 after 3 days of incubation at 35 °C. Fermented cinnamon showed an increase in ABTS, DPPH and H2O2 by 24.63, 58.31 and 60.27%, respectively over the control. Also, the total phenolic and flavonoid contents were increased, 8.15 to 11.40 mg GAE/g and 0.43 to 2.61 mg QE/g, respectively. The gallic acid, p-hydroxybenzoic acid, catechin and chlorogenic acid were increased by 37, 404, 11 and 98%, respectively. Also, anticancer activity was developed after fermentation. The increased antioxidant activity of fermented cinnamon could be attributed to the increase of some phenolics and flavonoids. Hence, cinnamon fermentation using L. plantarum is able to enhance its antioxidant and anticancer activities without producing toxic substances.

A Polymer Prodrug Strategy to Switch from Intravenous to Subcutaneous Cancer Therapy for Irritant/Vesicant Drugs.

Chemotherapy is almost exclusively administered via the intravenous (IV) route, which has serious limitations (e.g., patient discomfort, long hospital stays, need for trained staff, high cost, catheter failures, infections). Therefore, the development of effective and less costly chemotherapy that is more comfortable for the patient would revolutionize cancer therapy. While subcutaneous (SC) administration has the potential to meet these criteria, it is extremely restrictive as it cannot be applied to most anticancer drugs, such as irritant or vesicant ones, for local toxicity reasons. Herein, we report a facile, general, and scalable approach for the SC administration of anticancer drugs through the design of well-defined hydrophilic polymer prodrugs. This was applied to the anticancer drug paclitaxel (Ptx) as a worst-case scenario due to its high hydrophobicity and vesicant properties (two factors promoting necrosis at the injection site). After a preliminary screening of well-established polymers used in nanomedicine, polyacrylamide (PAAm) was chosen as a hydrophilic polymer owing to its greater physicochemical, pharmacokinetic, and tumor accumulation properties. A small library of Ptx-based polymer prodrugs was designed by adjusting the nature of the linker (ester, diglycolate, and carbonate) and then evaluated in terms of rheological/viscosity properties in aqueous solutions, drug release kinetics in PBS and in murine plasma, cytotoxicity on two different cancer cell lines, acute local and systemic toxicity, pharmacokinetics and biodistribution, and finally their anticancer efficacy. We demonstrated that Ptx-PAAm polymer prodrugs could be safely injected subcutaneously without inducing local toxicity while outperforming Taxol, the commercial formulation of Ptx, thus opening the door to the safe transposition from IV to SC chemotherapy.

Vitamin C-amino acid interactions in aqueous solutions: Volumetric and interfacial properties

Nature of interactions occurring in aqueous solutions have been studied to understand various phenomena such as protein stabilization, drug-delivery, and food preservation. These interactions have been studied by measuring physicochemical properties of mixed aqueous solutions. Herein, we have measured the volumetric and interfacial properties of vitamin C (VC) in aqueous solutions of amino acids (Glycine, Gly; L-Leucine, Leu). Volumetric were studied at temperatures (298.15 K to 313.15 K). Transfer volumes were obtained from infinite dilution partial molar volumes of VC in aqueous Gly-and Leu-solutions. Positive transfer volumes (∆tV2° and ∆tK2) were observed, which decreases as Gly > Leu, suggesting dominance of hydrophilic-ionic interactions. Double derivative, (∂2V2° /∂T2)P suggest chaotropic nature of VC in presence of amino acids. Nature of interactions influencing interfacial properties (contact angle and surface tension) has also been evaluated at 298.15 K. Solute-co-solute interactions not much influence the interfacial properties.