Properties Of Water Solutions Research Articles

Carboxymethyl hydroxypropyl guar gum physicochemical properties in dilute aqueous media

We investigate carboxymethyl hydroxypropyl guar gum (CMHPG) solution properties in water and NaCl, KCl, and CaCl2 aqueous solutions. The Huggins, Kraemer, and Rao models were applied by fitting specific and relative viscosity of CMHPG/water and CMHPG/salt/water to determine the intrinsic viscosity [η]. The Rao models yielded better results (R2 = 0.779–0.999) than Huggins and Kraemer equations. [η] decreased up to 84% in salt solution over the range 0.9–100 mM compared to water. Salt effects screened the CMHPG charged side groups chains leading to a compacted structure. In 0.9 mM NaCl(aq), the hydrodynamic coil radius (Rcoil) was 28% smaller and 45% smaller in 100 mM NaCl solution relative to water. Similar decreases were seen in KCl and CaCl2 solutions. KCl and CaCl2 were more effective than NaCl. CMHPG is salt-tolerant and shows comparatively less viscosity change than native guar gum, with modest reduced viscosity increases with CMHPG dilution at all salt concentrations. The electrostatic interactions were effective up to 100 mM salt. The activation energy of viscous flow for CMHPG solutions was computed and compared to measured xanthan gum and several literature values. These data show that the barrier to CMHPG flow is higher than for xanthan gum.

Properties of water solutions. The effective molality

Textbooks and research articles referring to properties of water solutions commonly state that Raoult’s law requires the diminution of vapor pressure of solutions of non-volatile solutes to be proportional to the mole fraction of solutes and that most solutions do not obey the law. This is wrong; twice. First: Raoult expressed concentrations in moles of solute per 100 mol of solvent, not in molar fractions; the two quantities are not related linearly. Second: The decrease in vapor pressure is linearly related to the effective molality of solute particles in adherence with the law as originally stated by Raoult and with the same slope for all solutes. In water solvent, molality is currently defined as moles of solute-derived particles in 55.509 mol (1.000 kg) of solvent. If a solute binds strongly with some water molecules, the bound waters become part of the solute and move as one unit with it, as noted by Einstein in 1906. Bound waters are no longer serving as solvent and are not available for binding with any additional solute. Hence, there are fewer than 55.509 mol of solvent and the effective molality of solutes changes accordingly. The importance of this was pointed out in 1912 by Arrhenius, in 1921 by Scatchard and in 1947 by Robinson. Neither they nor anyone else yet provided measures of these changes. The present work does so. Linearity is maintained up to the point where one half of the total water is bound. Past this, additional solute must remove water equally from free and from bound waters and linearity with the effective molality is no longer possible.

A rationale for non-linear responses to strong electric fields in molecular dynamics simulations.

Many approaches for calculation of the field-dependent electric properties of water solutions rely on the Onsager and Kirkwood theories of polar dielectrics. Such basic theories implicitly consider the electric field intensity to fulfill the so-called 'weak field conditions', i.e. to produce a linear response in the system. In this work we made use of molecular dynamics simulations to investigate possible non-linear effects induced by high intensity electric fields, specifically continuous wave bursts with nanosecond duration, comparing them with the ones predicted by the theory. We found that field intensities above 0.15 V nm-1 produce remarkable nonlinear responses in the whole 100 MHz-100 GHz frequency window considered, with the onset of higher order polarization signals, which are the clear fingerprint of harmonic distorsions. That non-linear response turned out to depend on the considered frequency. We finally show that MD outcomes are consistent with a modelization based on an extended formulation of the Langevin function including a frequency-dependent parameter.

STRUCTURE AND RHEOLOGICAL PROPERTIES OF WATER SOLUTIONS OF SODIUM CARBOXYMETHYL STARCH OBTAINED IN SOLID PHASE

Synthesis of the sodium salt of carboxymethyl starch was carried out by modification of corn starch in the solid phase. It was determined that moistening of the reaction mixture by small quantities of water, alcohols, and their water solutions caused a considerable increase in the degree of substitution of obtained products. By varying the ratio of the initial reagents and nature of solvent for moistening of reaction mixture samples of the sodium salt of carboxymethyl starch with the degree of substitution from 0.12 to 0.95 have from obtained. It was shown that the degree of substitution in obtaining product depended not only on the ratio of initial reagents but also on the nature of the used solvent. The morphology and structure of samples of the sodium salt of carboxymethyl starch have been investigated. By method of rotational, viscometry rheological properties of water solutions of the sodium salt of carboxymethyl starch was investigated and it was determined that with increasing degree of substitution dynamical viscosity of their solutions has increased

ОПРЕДЕЛЕНИЕ КОМПЛЕКСА ТЕПЛОФИЗИЧЕСКИХ СВОЙСТВ ВОДНЫХ РАСТВОРОВ БОРНОЙ КИСЛОТЫ ПРИ ПАРАМЕТРАХ ХАРАКТЕРНЫХ ДЛЯ АВАРИЙНОГО РЕЖИМА ВВЭР

The article presents the results of experimental studies of the thermophysical (density, viscosity) and physicochemical (degree of acidity - pH) properties of water solutions of boric acid. A review of the available literature data on the effect of the properties of boric acid solutions on heat removal from the reactor core is presented. It has been established that the available information is very general and does not cover the entire range of parameters (temperature, pressure, acid concentration) characteristic of a possible emergency at a nuclear power plant with a VVER reactor. Methods and facilities for conducting experimental studies are described. The results of experimental studies are presented. The density of aqueous solutions of boric acid with a concentration of 2.5-450 g/kg H2O at a temperature of 25-130 °C was determined. The dependence of the investigated characteristic on temperature and concentration was also obtained. The results of an experimental study of the kinematic viscosity of water solutions of boric acid with a concentration of 2.5-200 g/kg H2O at a temperature of 25-90 °C were obtained. The total error in measuring the viscosity of aqueous solutions of boric acid did not exceed 2 %. The pH values of water solutions of boric acid in the temperature range 25-50 and concentrations of 2.5-450 g/kg H2O were determined. The dependence for calculating the degree of acidity of boric acid is obtained. Experimental data on the thermophysical and physicochemical properties of water solutions of boric acid can be used to refine the results of calculations of emergency heat removal processes in a reactor facility, carried out using both one-dimensional calculation programs and three-dimensional CFD codes.

Decrease in the activity of irradiated graphite and liquid radioactive waste

Nowadays, the problem of nuclear waste deactivation is very urgent. The method proposed consists of exposing the aqueous solution of radionuclide to powerful nanosecond electromagnetic pulses by placing the treated solution between two electrodes connected to the outlets of the generator. Single-pole current pulses with a length of 1 ns, an amplitude of more than 5 kV, and a repetition frequency of 1 kHz are used. Such pulses can be obtained from the generator units with an amplitude of 5 kV to 15 kV. They have a pulse capacity of 1 to 4 MW, and the mains capacity is below 50 W. The pulse action leads to radiolysis of water and accelerated decay of radionuclides. As a result of radiolysis, hydrated electrons, hydrogen atoms, and various radicals are formed that causes precipitation of radionuclides, such as 137Cs and 90Sr. The description of several experiments and results of experimental investigations of the influence of powerful nanosecond electromagnetic pulses on the properties of water solutions with radioactive nuclides 137Cs and 90Sr and on items of irradiated graphite is presented. Under the influence of pulses on real liquid waste and aqueous solutions, radioactive nuclides in water are reduced by 5 to 50 times during 15 minutes. The effect described is preserved for 20 days. The reduction of beta activity twice during 25 min is observed in big blocks of the irradiated graphite. Flow-through unit for processing of liquid waste is developed, tested, and patented (RU 2726145. MPK G21F 9/28, July 7, 2020). This technology can be used to treat emergency solutions with tritium at Fukushima NPP. of the irradiated graphite.

Confined effect of water solution of ciprofloxacin in carbon nanotubes studied by Raman and Fourier Transform Infrared Spectroscopy methods

In this work we refer the properties of water solution of ciprofloxacin confined in single wall carbon nanotubes. Ciprofloxacin is well-known antibiotic applied against Gram-positive and Gram-negative bacteria. We study the influence of the size of nanotubes and their structure on interactions with the drug water solution. Analysis of Raman spectroscopy of the carbon nanotubes shows that the higher amorphousness of carbon nanotubes, which increase bio-capability of materials, is associated with their semiconductor’s properties. We used FT-IR spectroscopy to define the structure of confined ciprofloxacin, and we can assume what vibrations of functional group in the ciprofloxacin molecule have been suppressed by confining in the pores. ciprofloxacin, carbon nanotubes, drug delivery, raman spectroscopy, FT-IR.

Correlation and prediction of thermodynamic properties of dilute solutes in water up to high T and P. IV. Simple fluids He, Ne, Ar, Kr, Xe, Rn, H2, N2, O2, CO, CH4 - Re-parametrization

Fugacity coefficients of dilute aqueous solutions of six noble gases and simple fluids H2, N2, O2, CO, CH4 have been re-evaluated from ambient conditions (298 K, 0.1 MPa) to high temperatures (up to 2000 K) and water densities (up to 1500 kg m–3). The main goal of the reevaluation is to provide an agreement within 1% with experiment-based values of the vapor-liquid distribution constants, KD, which are known for simple fluids (except Rn) in water with high precision all the way to the critical point of water at 647.096 K. As before, the approach is based on a correlation developed for the function, A12∞=V2∞/κTRT, and includes known constraints: second virial coefficients at low water densities, hard sphere behavior at high water densities, near-critical principles, and corresponding-states relations. A comparison with literature data at subcritical (Henry's and vapor-liquid distribution constants) and supercritical temperatures (fugacity coefficients) is made.

Physical properties of water solutions at high dilutions of basic substances

Physical properties of water solutions at high dilutions of basic substances

ВПЛИВ ЕЛЕКТРОМАГНІТНОГО ВИПРОМІНЮВАННЯ МІЛІМЕТРОВОГО ДІАПАЗОНУ НА ОПТИЧНІ ВЛАСТИВОСТІ ГЕМОГЛОБІНУ

The biological activity of millimeter electromagnetic radiation (MEMR) has long been known that is the basis for its use in medicine. But the primary biophysical mechanisms of this factor at the molecular level remain poorly understood and debated. Because of it the features of the influence of microwave radiation on the optical properties of water solutions of hemoglobin with the aim to characterize the certain structural state of hemoglobin were investigated in this research. The object of the study was the optical properties of aqueous solutions of human hemoglobin in the concentration range of 7 and 15 μM and in the temperature range 10–40°C. The optical spectra were recorded by using a BiospecMini (Shimadzu) spectrophotometer in the wavelength range of 190–1100 nm. In order to increase the accuracy of the analysis of spectral data the spectra were normalized relative to the baseline which was taken as a line that ran parallel to the horizontal axis due to the minimum value of the optical density in the absorption spectrum. The values of the absorption maxima and the optical density were used as the main parameters of the absorption spectra. The B-spline function was used to more accurately determine these parameters. Microwave exposure of hemoglobin solutions was performed at wavelength of 7,1 mm with power that calculated to be approximately 6mW. This power of electromagnetic radiation corresponds to the conditional limit range between thermal and non-thermal action of this factor. The dependence of the optical properties of hemoglobin in the spectral range of heme absorption on temperature was analyzed and effects of microwave radiation on the optical properties of hemoglobin solutions were considered in frame of hypochromic effects induced by temperature. It was revealed that the parameters of the absorption spectrum of an aqueous solution of hemoglobin depend on temperature. The optical density in the Sore band and the spectral bands of the oxygenated form of hemoglobin decreases upon temperature increase. The observed temperature hypochromic effect is associated with increased protein aggregation. The effect of MEMR leads to a small but statistically significant hypochromism in the spectra of hemoglobin absorption that testifies an increase in protein aggregation under the action of this physical factor which cause the changes in the hydration of protein molecules. This effect depends on the protein concentration and is not detected at low concentrations.

Amphiphilic Copolymers Derived from Butanosolv Lignin and Acrylamide: Synthesis, Properties in Water Solution, and Potential Applications

In this work, a series of amphiphilic lignin-acrylamide copolymers was synthetized via a grafting fromapproach using α-butoxylated organosolv lignin. This lignin is obtained in high yield via a mild organosolv extraction with butanol and contains a well-defined modified β-O-4 structure that allows for site-selective modification of the primary alcohol in the γ-position. The modified lignin was then used as a precursor of amphiphilic copolymers by reaction with acrylamide, either via free radical polymerization or via atom transfer radical polymerization after converting the lignin into a suitable macroinitiator. The effect of the synthetic method and acrylamide/lignin ratio on the final properties was studied and compared. Relevant solution properties, in particular, shear viscosity and interfacial and surface tension, showed that different synthetic methods and polymer compositions allow a tuning of the solution behavior toward specific potential applications, such as emulsion stabilization or enhanced oil recovery. Furthermore, it was preliminarily shown that the obtained polymers may potentially display low cytotoxicity, further increasing the possibilities for applications.

Preliminary evaluation of amphiphilic block polyelectrolytes as potential flooding agents for low salinity chemical enhanced oil recovery

Amphiphilic block polyelectrolytes are known for their remarkable thickening properties in water solution, originating from their ability to self-assemble into large micellar aggregates. This makes them promising flooding agent for chemical enhanced oil recovery (cEOR). However, to the best of our knowledge, they have not yet been directly investigated for this purpose. In this work, a survey of relevant properties for EOR (rheology, filterability and emulsification), and laboratory scale oil recovery experiments, were performed on water solutions of polystyrene-block-poly(methacrylic acid) amphiphilic block polyelectrolytes, and compared with a commercial partially hydrolyzed polyacrylamide (HPAM), to evaluate the real potential in EOR applications for the first time. It was found that the recovery of amphiphilic block copolymers in low salinity brine (0.2% concentration of NaCl) is remarkably higher than that of HPAM at comparable weight concentration and shear viscosity, despite a much lower molecular weight. Effect of salinity and emulsification properties of the studied polymers have also been preliminarily investigated. Our results suggest that the recovery mechanism of these polymers differs from the traditional mechanism of polymer flooding, possibly due to emulsification of the oil. In conclusion, the studied amphiphilic block polyelectrolytes show promise as chemical agents in low salinity polymer flooding.

Correlation and prediction of thermodynamic properties of dilute solutes in water up to high T and P. III. Polar and aromatic solutes H2S, C6H6, C7H8, CH3SH, SO2, HCN, acetone, NH3, CH3NH2, CH3OH, C2H5OH, phenol

Fugacity coefficients of twelve polar or aromatic species at infinite dilution in water (H2S, benzene C6H6, toluene C7H8, methanethiol CH3SH, SO2, HCN, acetone (CH3)2CO, NH3, methylamine CH3NH2, methanol CH3OH, ethanol C2H5OH and phenol C6H5OH) have been evaluated from ambient conditions (298 K, 0.1 MPa) to high temperatures (up to 2000 K) and water densities (up to 1500 kg m–3). The approach is based on a correlation developed for the function, A12∞=V2∞/κTRT, and includes known constraints: second virial coefficients at low water densities, hard sphere behavior at high water densities, near–critical principles, and corresponding–states relations. A comparison with literature data at subcritical (Henry's and vapor–liquid distribution constants) and supercritical temperatures (fugacity coefficients) is made.

Effects of Organic Materials Obtained from Different Tree Species on Some Chemical Parameters of Water Quality (Study Case of Andirin-Akifiye Forest Management Unit)

Mineral substance concentrations are very important in terms of the levels of chemical quality in drinking water. A highly important source of minerals in water comes from the litter layer of the forest floor which is also a source of organic matter. This research investigates the contribution of organic litter formed in pure pine, cedar and beech forests to the quality parameters of water in the Andirin District of Kahramanmaraş province. A total of 90 organic matter samples were systematically collected from three different forest ecosystems. Some chemical properties of water solution were obtained from the organic matter using the ICP-OES device. This revealed that aluminum, boron, zinc, iron, cadmium, calcium, cobalt, magnesium, manganese, nickel and potassium parameters were present in the water. In addition, pH, EC and temperature measurements were taken. The results revealed lower amounts of chemicals in the waters obtained from the dead vegetation covers of the beech forests, showing elements such as aluminum, iron, magnesium, cobalt, and nickel levels to be 0.146 mg; 0.114 μg; 5.54 mg; 0.0006 μg and 0.0054 μg, respectively, compared to waters obtained from cedar and pine forest ecosystems. It was found that different organic materials had significantly different mineral concentrations affecting the chemical quality of the water. However, waters affected by the dead vegetation cover of the forest ecosystem were determined to comply with the standards of drinking and irrigation water according to current regulations. 

Influence of a Constant Magnetic Field on Some Properties of Water Solutions

The effect of a static magnetic field with induction up to 7 T on the concentration of dissolved molecular oxygen, the concentration of hydrogen peroxide, the redox potential, and the electrical conductivity of aqueous solutions with a low concentration of active impurities is studied. It was shown that the concentration of dissolved molecular oxygen in water under the exposure of a magnetic field with induction up to 7 T does not change significantly, while the concentration of hydrogen peroxide increases linearly. It has been established that the pH value of water with field amplification in this induction range tends to decrease within 10%. With an increase in induction, an increase in the redox potential of water is observed. The change in its value is approximately 7 mV/T. It was shown that, with an increase in induction up to 2 T, the electrical resistivity of the water under study drops to about 0.6 MΩ cm, while at higher values of induction it practically does not change.

Correlation and prediction of thermodynamic properties of dilute solutes in water up to high T and P. II. Normal fluids CO2, C2H4, C2H6, C3H8, n-C4H10, i-C4H10, functional groups CH3 and CH2

Fugacity coefficients of dilute aqueous solutions of six species belonging to normal fluids (CO2, C2H4, C2H6, C3H8, n-C4H10, i-C4H10) as well as functional groups CH3 and CH2 have been evaluated from ambient conditions (298 K, 0.1 MPa) to high temperatures (up to 2000 K) and water densities (up to 1500 kg m−3). The basis of the approach is a correlation developed for the function, A12∞=V2∞/κTRT, that includes known constraints: second virial coefficients at low water densities, hard sphere behavior at high water densities, near-critical principles, and corresponding-states relations. A comparison with literature data at subcritical (Henry's and vapor-liquid distribution constants) and supercritical temperatures (fugacity coefficients) is made. For aqueous CO2, the agreement with literature data is generally satisfactory. It is shown that for other solutes existing disagreements can be traced mostly to the values of the second cross virial coefficients employed in the literature models, suggesting the room for improvement of existing recommendations.

Herbal Shampoos Based on Vegetable Waste Production

Currently, much attention is paid to the development of consumer products based on secondary resources, in particular using production waste. One of the perspective directions of using of plant waste products is their use for making shampoos. This article presents the results of studying of influence of tinctures of blueberry leaves tall (Vaccinium corymbosum) and seed buckwheat grass (Fagopyrum esculentum) on the index of quality of the developed shampoos. An anionic surfactant (SLES, IFRAPON LOS 2 N 70 trademark) was introduced into the composition of the developed shampoo. This is due to variety of causes, for example, it has a more gentle effect on the scalp and hair compared to other sorts of surfactants. Physicochemical parameters characterizing the basic properties of water solutions of anionic surfactants, such as foam number, foam stability, pH, and conditional viscosity, are determined. It was determined that optimal concentration of anionic surfactant for introducing shampoo into the composition is 0.02 % (mass). It was also determined that optimal condition of tincture of blueberry leaves and tincture of buck-wheat grass in the composition of shampoo is 10 % (vol.). Thus, the introduction of tinctures of said plant raw materials into shampoos provides technological index of shampoos at the level of indicators established in GOST 31696-2012, and the biologically active substances contained in tinctures certainly have a positive effect on the scalp and hair of consumers

Determination of the physicochemical properties of boric acid for VVER emergency modes

The results of experimental research of physicochemical properties of water solutions of H3BO3 are presented in this article. The literature review about the influence of hydrogen ion exponent of H3BO3 solutions on its heat and mass transfer, and corrosiveness of an acid in the VVER reactor core in is given. It is found that the existing data does not cover the entire range of parameters (acid concentration, temperature and pressure) characteristic of a possible Loss-of-Coolant Accident (LOCA) at nuclear power plant with a VVER. The problem of the accumulation and crystallization of boric acid in case of LOCA and the operation of passive safety systems (such as hydro accumulators of the first, second and third stages, and a passive heat removal system) is formulated. Test equipment and techniques of research are described. The generalizing equations for the pH and acidity constant of hydrous solutions of H3BO3 in range of the concentration (5-100 gkg−1 H2O) and temperature (25-50 °C) has been obtained.

Изучение свойств системы "вода–анионный ПАВ–настойка плодов голубики"

This study is dedicated to the development of a new shampoo based on plant raw material using water tinctures of high-quality blueberry fruit Vaccinium corymbosum L. We used blueberry fruit of Bluecrop sort, the choice of this variety is based on its popularity and wide spread in the Republic of Belarus. This paper introduces a method of obtaining the tincture of blueberry fruit: the size of crushed raw material is 0.3--1.0 mm; the raw material : extractant ratio is 1 : 10; the extractant is drinking-water; the infusion time is 1 day. We analyzed the complex of biologically active substances in the tincture, contained in it, such as anthocyanins, tannins, carbohydrates, flavonoids. To choose the concentration of anionic SAA, i.e., water solution of sodium laureth sulfate, its foam forming properties in a concentration range of 0.01--5.00 % (ln c from --4.6 to 1.6) were previously determined. It was established that optimal concentration of SAA which provides foam forming properties on the required level for hygienic detergents is 0.02%. The effect of the tincture of blueberry fruit on the properties of water solutions that contain SAA was also investigated. Findings of research show that to meet the requirements for hygienic detergents, which means that the foam number of shampoo should be at least 100 mm, and foam stability should be not less than 80 %, the concentration of the tincture of high-quality blueberry fruit in solution of sodium laureth sulfate should be no more than 10 %.

Poly(2-propyl-2-oxazoline)s in Aqueous Methanol: To Dissolve or not to Dissolve

At room temperature, poly(N-isopropylacrylamide) (PNIPAM) is soluble in water and methanol, but it is not soluble in certain water/methanol mixtures. This phenomenon, known as cononsolvency, has been explored in great detail experimentally and theoretically in an attempt to understand the complex interactions occurring in the ternary PNIPAM/water/co-nonsolvent system. Yet little is known about the effects of the polymer structure on cononsolvency. To address this point, we investigated the temperature-dependent solution properties in water, methanol, and mixtures of the two solvents of poly(2-cyclopropyl-2-oxazoline) (PcyPOx) and two structural isomers of PNIPAM (Mn ∼ 11 kg/mol): poly(2-isopropyl-2-oxazoline) (PiPOx) and poly(2-n-propyl-2-oxazoline) (PnPOx). The phase diagram of the ternary water/methanol/poly(2-propyl-2-oxazolines) (PPOx) systems, constructed based on cloud point (TCP) measurements, revealed that PnPOx exhibits cononsolvency in water/methanol mixtures. In contrast, methanol acts as a cosolvent for PiPOx and PcyPOx in water. The enthalpy, ΔH, and temperature, Tmax, of the coil-to-globule transition of the three polymers in various water/methanol mixtures were measured by high-sensitivity differential scanning calorimetry. Tmax follows the same trends as TCP, confirming the cononsolvency of PnPOx and the cosolvency of PiPOx and PcyPOx. ΔH decreases linearly as a function of the methanol content for all PPOx systems. Ancillary high-resolution 1H NMR spectroscopy studies of PPOx solutions in D2O and methanol-d4, coupled with DOSY and NOESY experiments revealed that the n-propyl group of PnPOx rotates freely in D2O, whereas the rotation of the isopropyl and cyclopropyl groups of PiPOx and PcyPOx, respectively, is limited due to steric restriction. This factor appears to play an important role in the case of the PPOxs/water/methanol ternary system.