Solutions Of Surface-active Substances Research Articles

Bubble Formation and Motion in Liquids—A Review

In flotation, a bubble acts as a carrier for attached particles. The properties of the gas–liquid interface of the bubble are one of the main factors determining the bubble motion and flotation efficiency. Monitoring of the bubble motion may deliver interesting information about the state of the gas–liquid interface. In the case of pure liquids, a bubble surface is fully mobile, while the presence of surface-active substances (e.g., surfactants) causes diminishing bubble velocity due to the retardation of the interface fluidity. The theoretical prediction of the terminal velocity value for the bubble has been investigated for over a century, delivering a number of various models describing bubble motion in a liquid. This narrative review is devoted to the motion of the bubble in stagnant liquids and is divided into three main sections describing: (i) experimental techniques for tracking bubble motion, (ii) bubble motion and shape deformation in clean water, and (iii) bubble motion in solutions of surface-active substances.

Получение микродисперсного тканеспецифического децеллюляризованного матрикса из суставного хряща свиньи

A method for obtaining a microdispersed tissue-specific matrix from decellularized porcine articular cartilage while maintaining morphological and functional properties of the extracellular matrix with no signs of cytotoxicity was developed. The cartilage particle size distribution in suspension after cryogenic grinding was determined using laser diffraction analysis. The range of sizes of the obtained cartilage microparticles suggests the possibility of their administration by injection (<220 μm). The combination of stages, including three freeze/thaw cycles (–196/37°C) followed by treatment with solutions of surface-active substances (surfactants), sodium dodecyl sulfate and Triton X-100, and DNase resulted in the complete removal of non-decellularized microparticles. The residual DNA content was 9.11 ± 1.13 ng/mg of tissue. The effectiveness of surfactant washing was assessed by the cytotoxicity of the matrix on the culture of human adipose derived mesenchymal stromal cells (hADSCs). To assess the hemocompatibility of the obtained samples, their hemolytic activity was studied in vitro. The adhesion and proliferation of hADSCs on the matrix surface were studied on day 21 of cultivation. The matrix did not exhibit hemolytic activity and cytotoxicity with respect to hADSCs. hADSCs in the samples were actively proliferating on the matrix surface. The biocompatibility and hemocompatibility of the obtained matrix in vitro indicate its potential for application in cartilage regenerative medicine.

Influence of Dispersed Systems on Exploratory Well Drilling

Results of theoretical, laboratory and stand study which enabled to recommend solutions of surface active substances while well drilling, taking into account mining and geological conditions of a number of Ukrainian regions are given. It was determined that addition of surface active substances to the drilling fluid during rotary drilling by hard-face and diamond cores makes it possible to increase drilling rate.

UV Absorbance of Aqueous DNA

The UV absorption spectra of water with different electric charge (potential) were obtained. It was shown that UV absorption spectra of water with negative electric charge (potential) have the sharp peaks with maximum in the range 190 – 200 nm and UV absorption spectra of water with positive electric charge (potential) have the wide peaks with maximum in the range 200 – 220 nm. It was asked to explain this absorption. It was also established that UV absorption spectra of water solutions of surface inactive substances have sharp peaks with a maximum in the range 190 – 200 nm and UV absorption spectra of solutions of surface active substances have the wide peaks with a maximum in the range 200 – 220 nm. The UV absorption spectra of DNA solutions, which were prepared on the water with different electric charge (potential), were obtained. It was shown that these spectra are dependent on the electric charge (potential) of water used. It was proposed that UV absorption spectra of aqueous DNA reflect mostly the spectral properties of charged water or charged cuvette.

Modeling of the kinetics of pyrene-bromide phosphorescence in aqueous-micellar media

This work is devoted to a study of the processes of an increase in the phosphorescence intensity upon photoirradiation of pyrene bromide in aqueous-micellar solutions of surface-active substances. The method of mathematical modeling of the pyrene bromide triplet state deactivation processes is used to determine the rate constant of phosphorescence quenching of pyrene bromide solubilized in sodium dodecyl sulfate micelles by oxygen.

Thermodynamic Characteristics of Micelle Formation in Aqueous Solutions of Surface-Active Substances

A phenomenological model of micelle formation in aqueous solutions of surface-active substances is suggested. The model is based on the hypothesis according to which the molecular solution—micellar solution transition is a third-order phase transition. Analytic interrelations between micellar solution characteristics were obtained, and an equation for its thermodynamic potential formulated. An analytic description of the influence of micelle formation on the velocity of sound in solution was suggested.

Separation of Mineral Raw Material in the Activated Aqueous Dispersions of Air

The results of investigations into physical-chemical processes proceeding in the dispersed air bubbles in the solutions of surface-active substances are presented. It is established that a specially prepared activated aqueous dispersion of air interacts actively with minerals which attach on the surface of bubbles. A new pneumatic flotation machine and devices adapted to the existing flotation machines are created to obtain dispersion. Using apatite, fluorite, sylvinite, copper-nickel, and antimony ores as an example, the efficiency of their separation is shown under stated conditions.

Displacement of oil by a solution of an active and a passive additive

A study is made of the frontal displacement of oil from a homogeneous porous medium by a solution of an active additive in the presence in the flow a component (referred to as the passive additive) that does not directly influence the ratio of the mobilities of the water and the oil but does interact with the active additive, changing its adsorbability and (or) its distribution between the phases [1]. Such a situation arises when oil is displaced by solutions of surface-active substances and other reactants, whose effectiveness in application is significantly reduced by their adsorption by the porous medium (if the adsorbed matter itself does not reduce the mobility of the water, as in the case of the polymer in [2]). Under these conditions, it may be worth adding to the solution of the surface-active substance some cheap ballast substance that does not change the ratio of the mobilities of the phases but is capable of “taking away” from the surface-active substance some of the adsorption centers on the surface of the porous skeleton. Another example of a passive additive is provided by salts dissolved in water that influence the distribution of the active impurity between the water and the oil; this occurs in the case of displacement by carbonated water due to the dependence of the solubility of carbon dioxide gas in water on the mineralization of the water [3]. In the present paper, an investigation is made of the structure of the displacement front, and a technique is developed for constructing a self-similar solution in the case when the adsorbability of the passive additive and its distribution between the phases do not depend on the concentration of the active additive.

Turbulent flows of solutions of surface-active substances

Not only polymers, but also some surface-active substances have the capacity to reduce the hydrodynamic resistance in the turbulent regime of a fluid. From the point of view of stability against mechanical destruction, the addition of surface-active substances has certain advantages over polymers; in particular, they are capable of recovering their hydrodynamic effectiveness having passed through pumps and local points of resistance [1]. The basic possibility of reducing drag by the addition of surface-active substances was demonstrated in [2–6]. It was later shown that a reduction in the drag of liquids could be achieved only by micelle-forming surface-active substances [5, 7], in solutions of which spherical and platelike micelles, respectively, are formed at the critical concentrationsCm1 andCm2 for micelle formation. The values ofCm1 andCm2 depend both on the molecular structure of the surface-active substances as well as on external factors such as the temperature, the presence in the solution of electrolytes, polar organic substances, and so forth. The connection established in [5, 7] between the reduction in the drag and the value ofCm2 suggests that the reduction in the turbulent friction will also depend on the above factors. It is therefore possible to control processes of turbulent transfer in a fluid as well as the drag. However, this possibility has not been sufficiently studied. In [1–7], the influence of surface-active substances on the drag was investigated. First data on the velocity profiles in solutions of surface-active substances were given in [9, 10]; they are not sufficiently complete. In the present work, we made measurements of the velocity profiles and the turbulence intensity in solutions of surfaceactive substances, and we have calculated the generation of turbulence energy and the dissipation of the energy of the averaged motion. We have studied the influence of electrolytes and the temperature on the reduction in the drag and give the results of full-scale experiments.

脂質の酸化と生体への影響

It is well known that the lipids carrying unsaturated fatty acids are susceptible to oxidation or peroxidation resulting free radical formation.Lipid peroxide or free radical gives generally the damage on cell membrane structure, especially on enzyme system.From these reasons, the relations between clinical symptoms and oxidized serum or organs have recently been investigated. The relations on several organs are described as follows : 1) Lung. Lung is the most active organ synthesizing phospholipids, because the inside of alvolis are wetted by the solution of surface active substance so called pneumosurfactant to decrease the surface tension of water layer on the surface of alvolis. If we give O3 or NO2 gas to rats or rabbits by respiration they die more faster without the administration of tocopherols than the animals in normal conditions.2) Liver. In liver disease, the peroxide value of serum is in parallel to the condition of disease. It is recommended to decrease its value even in the case of surgery operation with large amounts of blood transfusion.3) Brain. In adult brain, the deposit of yellow pigments on the surface of brain tissue is found. The pigments are identified as fuchsin bases which are attributed to the condensation between malondialdehyde, product from lipid peroxidation and amino compound. But unfornutately, the relation between the formation of fuchsin base, so called lipofuscin and the deterioration of the functions of brain has never been clarified.There are a few procedures to assay the content of peroxided products in serum or organs.Thiobarbituric acid method (TBA) is widely utilized according to its easiness, but this method has many defects or doubts to measure the peroxidized products.According to Tappel et al, the procedure for fluorescent spectra has been developed, which is due to the fluorescent product formation between malonaldehyde and amino compounds.

One-dimensional displacement of petroleum by aqueous solutions of sorption agents taking account of interlayer return flows

Experimental and theoretical investigations of the process of the displacement of petroleum by aqueous solutions of surface-active substances (surfactants), polymers, micelle solutions, and their combinations show that sorption phenomena can exert a considerable effect on the process of flooding [1, 2]. In some cases, they can lead to an appreciable lag of the front of the dissolved substance behind the carrier liquid and to the appearance of a second jump in the saturation of the displacing liquid [1, 3]. In [4] a mathematical model is proposed for the displacement of petroleum from a laminar stratum with isolated intercalculations of aqueous solutions of surfactants and polymers, taking account of sorption phenomena. In the present article, a study is made of the displacement of petroleum from a stratum by aqueous solutions of sorption agents, taking account of interlayer return flows of liquids.

Study of the turbulent flow of solutions of surface-active materials by means of a laser anemometer

The results of measurements carried out on the mean velocity profile in aqueous solutions of surface-active substances (SAS) are presented. It is shown that the introduction of SAS additives to a turbulent flow of liquid leads to a considerable change in the distribution of the mean-velocity profile over the whole flow cross section.

Strong adsorption from highly dilute solution: adsorption of sodium dodecyl sulfate from saturated ammonium sulfate solution

A method was devised to obtain a correct surface tension vs. equilibrium concentration curve for a very dilute solution of surface active substance, such as sodium dodecyl sulfate dissolved in an aqueous solution of saturated ammonium sulfate, where the decrease of the bulk concentration due to the adsorption is not negligible. Adsorption isotherm was obtained by applyingGibbs adsorption equation to the curve, and the pressure vs. area curve was plotted. The latter plot is in agreement with that directly measured for the spread film on saturated ammonium sulfate solution, the surface pressure of which was obtained by the extrapolation to time zero of the plot of log surface pressure vs. square root of time. The amount of calculated saturation value is in agreement with that directly measured by the radiotracer method. These agreements show the validity of the present method of obtaining surface tension and adsorption isotherms, together with the method of extrapolation to obtain the surface pressure vs. area curve for soluble film.

The velocity of air bubble ascending in aqueous solution of surface active substance and inorganic electrolyte

A series of measurements of falling velocities of glass sphere in an aqueous solution of sodium dodecyl sulfate and in pure water were carried out to elucidate the decrease in ascending velocity of air bubble in water due to the presence of surface active substance. From this, it was confirmed experimentally that the air bubble rises as a sphere and the air circulation inside the bubble is the sole factor in increasing rising velocity in the region of bubble radius from 0.03 to 0.07 cm, and that the circulation is actually suppressed by the adsorption of surface active substance.

The electrodialysis of the aqueous solution of surface active agent

A new electrodialysis method for the study of micelle formation on aqueous solution of surface active substance is proposed. This method has advantages among other procedures using semipermeable membrane, in that (1) the time required for the measurement is far less than that of any other methods, thus the membrane can be practically rendered to be semipermeable for micelles, and (2) it is not essentially required to add an inorganic salt to inhibit the micelle permeation, so we are able to know, without extrapolation, the behavior of surface active substance free from the salt influence. We observed a sharp break point on the dialysis curve, and found that the point corresponded with the accepted CMC value of 7.4 × 10−3 mol/l for sodium dodecyl sulfate.

The effect of surface active substances on the diffusion of water through membranes

According to the investigations of Jacques Loeb, the diffusion of water through membranes is a linear function of the solute, as would be expected according to the law of van't Hoff, only if the concentration of the salt solution is greater than M/16. In lesser concentrations than this the so-called “initial rate” of diffusion is represented by a curve having a maximum corresponding to a concentration varying from M/512 to M/256. If the concentration becomes greater the rate of diffusion decreases until a concentration of M/16 is reached. The experiments of Loeb, and of Bethe and Toropoff seem to indicate the identity of electro-osmosis and free osmosis in low concentrations, and in this way furnish the explanation of the influence of electrolytes on the rate of diffusion by the difference of effect of the ions on the quantity of charge on the Helmholtz double layer on the capillary walls. Grumbach has shown that surface active substances exert an influence on capillary electric forces and consequently on the diffusion potential. Our own investigations are concerned with the influence of surface active substances on the capillary kinetic phenomena. Collodion sacs of 50 cc. capacity were attached to upright manometer tubes of 2 mm. diameter. The sacs were made on the inside of a 50 cc. Erlenmeyer flask, coated twice with 4 per cent collodion, and dried for one-half hour after the first coating, and 4 to 5 hours after the second. The sacs were filled with electrolytes of M/32 concentration immersed in distilled water. In the case of a given electrolyte the manometer readings obtained with different sacs were relatively constant. Having established the normal rate of diffusion, the sacs were treated by filling them with solutions of surface active substances.