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Nataliya A Mishchuk

Nataliya A Mishchuk
Institute of Colloid and Water Chemistry, Ukraine · Electrochemistry of Disperse Systems

Professor, Doctor of Sciences

About

146
Publications
19,603
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1,946
Citations
Additional affiliations
March 2005 - September 2005
University of Granada
Position
  • Professor
September 2002 - November 2002
Aix-Marseille Université
Position
  • Professor
January 2001 - December 2001
Max Plank Institute for Colloid and Surface Chemistry
Position
  • Professor

Publications

Publications (146)
Article
Experimental data on the freezing rate and formation of cylindrical and spherical gas inclusions occurring in ice during the cooling of distilled water being in equilibrium with air at different initial temperatures of water and air and during the nonuniform cooling of a vessel with water have been obtained. The shape, size, and location of emergin...
Article
The forces of interaction between hydrophilic disperse particles in a humidified dispersion have been analyzed. The minimum volume fraction of water, which is acceptable for the application of DLVO theory formulas in computing the interaction between particles, was determined. It is shown that the formation of thin restricted water layers in gaps b...
Article
This study deals with the possibility of inactivation of micromycetes under the influence of electric field with intensity 100–185 V/cm and the temperature increased to 45–65°C. The regularities of the filtration process of Candida albicans micromycetes on the bed of AB-17 anion-exchange granules placed into electric field have been established. Th...
Article
Electrofiltration of the particles of cation exchanger KU-2-8 and anion exchanger AV-17 pounded to the size (1–4) μm through a granulated cation exchanger KU-2-8 was investigated. The interval of electric field strength and flow velocities of a filtered liquid, which achieves a stable 99% degree of decontamination, is determined. Features of the im...
Article
Full-text available
The relationships of coefficients of molecule diffusion, viscosity, thermal capacity, thermal conductivity and other properties of water as a function of temperature and pressure have been analyzed. It is shown that the main regularities of changes in water characteristics, including qualitative differences of its behavior from the rest of molecula...
Article
The paper has analyzed relationships between lengths of covalent and hydrogen bonds and characteristic distances between oxygen atoms in water and ice, and also density of water and its isobaric and isothermal compressibility on temperature and pressure. It is shown that regularities of changes in properties of water are determined by the features...
Article
The dependence of the attraction energy of particles on the formation of thin layers on their surface with characteristics different from those of dispersion medium has been investigated. It is shown that at local reduction of the water density or formation of gaseous interlayer on the surface of hydrophobic particles, their attraction at small dis...
Article
The article has proposed a new method of intensification of the dehydration of clayey dispersion based on the use of an electrochemically active diaphragm. Analyzed was impact of a carbon diaphragm on the distribution of the field tension in a cell and the electroosmotic transport of the liquid at different pH of the porous solution. Optimal condit...
Article
The paper has investigated the efficiency of dehydration of two-component dispersion system in its mechanical treatment and additional effect of the electric field. It is shown that at the presence of a gel-like organic component substantially making difficult the process of removing liquid, the degree of dehydration noticeably decreases. For achie...
Article
The paper carries out a theoretical and experimental research of the electrohydrodynamic transport of the dye ions in the intermembrane channel. The paper has established main regularities of processes that go on and determined optimal conditions for separation of the effluent and concentrated dye.
Article
The paper deals with the investigation of dehydration of dispersed systems at combination of pressure and the electric field. Main regularities of processes taking place have been established and analyzed and determined optimal conditions of removing liquid.
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Full-text available
The article gives experimental data on the rate of water freezing and formation of cylindrical and spherical gas inclusions appearing in ice during cooling of water, which is in equilibrium with the atmosphere. Proposed are theoretical models describing changes of the aggregate state of water, concentration of gas and formation of porous ice. The a...
Article
The two-layer spherical cell model to describe the equilibrium electrical potential distribution between strongly charged particles in a monodisperse system is proposed. It is shown that the general solution of the Poisson-Boltzmann equation can be obtained by a combination of its solutions in the approximation of the excluded co-ions for the inner...
Data
Potential drop distribution in a system comprising ion�exchange membranes, a diaphragm, and an ion�exchange resin layer has been experimentally studied and theoretically analyzed. It has been estab� lished that the potential drop is redistributed in the system due to not only different electrical resistances of its elements, but also their concentr...
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Potential drop distribution in a system comprising ion�exchange membranes, a diaphragm, and an ion�exchange resin layer has been experimentally studied and theoretically analyzed. It has been estab� lished that the potential drop is redistributed in the system due to not only different electrical resistances of its elements, but also their concentr...
Article
A model of collision and collection of Brownian submicron particles based on the creation of a convective-diffusion layer near a bubble surface and overcoming the energy barrier created by particle/bubble interaction is developed. Simple analytical expressions describing the rate of collision and collection efficiency are obtained. The collision an...
Article
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A theoretical model of the electroosmotic and hydrodynamic flow in cylindrical and rectangular microchannels, after the application of a stepwise and sinusoidal voltage, is presented. The analytical and numerical analysis, performed for transient processes and a few types of periodical and aperiodical modes, shows the qualitative peculiarities of t...
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A micropump based on strong polarization of ion-exchange beads and corresponding actuation by electroosmosis of the second kind was designed and fabricated. Experimental results from operation with AC and DC voltage showed a close to second order relationship between flow and voltage, in good agreement with theory. The difference between experiment...
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Peculiarities of the particle interaction and the kinetics of Brownian coagulation in diluted and concentrated disperse systems and their dependence on the characteristics of disperse medium, the size and surface properties of particles have been analyzed. Keywordsdisperse system–Brownian coagulation–kinetics–colloid chemistry–stability–attraction...
Article
The present article focuses on the analysis of experimental data and interpreting of the influence of water depletion near hydrophobic particles and nanobubbles formed on their surface or in the space between them on van der Waals and electrostatic components of interparticle interaction. It is shown that the difference between simplified and more...
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The paper contains theoretically substantiated conditions of hydrodynamic regulation of the pH of the porous solution in concentrated aqueous dispersion systems without introduction to them of aggressive chemical reagents. The provision of optimal pH values makes it possible to raise the electrokinetic potential of disperse particles and, according...
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The mechanisms of generation of aerosols at water surface and their dependences on the local state of the atmosphere and water bodies, and also on the transport processes in the atmosphere have been studied. The possible disperse and chemical compositions of aerosols and their main determining factors and also the role of aerosols in the interactio...
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Linear and nonlinear electrophoresis of conducting and nonconducting spherical disperse particles is studied. A comparative analysis is performed for the regularities of nonlinear electrophoresis in the stationary and pulsed modes at small and large Peclet numbers.
Article
The review addresses the peculiarities of concentration polarization caused by an electric current passing through conducting and around nonconducting charged materials. The conditions of emergence of an induced space charge of large density and thickness behind an electrical double layer, leading to strong non-linearity of electroosmosis and elect...
Article
Using uranium and copper, entered in parallel, as an example, experimental investigations of the mechanisms of removal of these ions from soils with different exchange and buffer capacities have been performed. The experiments revealed that the simultaneous action of electrochemical, physicochemical, and chemical factors cause an essential nonunifo...
Article
Full-text available
A microfluidic pump based on electroosmosis of the second kind was designed and fabricated. Experimental results using DC and AC voltages showed a close to second-order relationship between flow and voltage, in good agreement with theory. The experimental flow rates were considerably lower than the predicted maximum for the micropumps, which can be...
Article
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We have developed a theoretical model describing electromigration processes in the soil with a low exchange capacity. We have also investigated features of electromigration of ions in the galvanostatic and potentiostatic modes with a different ratio of electromigration mobilities of cations and anions present in the soil and that of a substituting...
Article
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We have proposed and theoretically substantiated the hydrodynamic method of regulating the pH during electric treatment of moisture-containing disperse systems, namely: clay-containing sludge and various types of soils. We have conducted experimental verification of the proposed method and theoretical analysis of the obtained data. It is shown that...
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We have investigated the kinetic curves of hydrogen peroxide decomposition of copper chloride and potassium bichromate. It has been shown that depending of the pH value and the phase state of the solution the decomposition rate may vary tens of times. We have conducted a theoretical analysis and modeling of obtained regularities.
Article
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The conditions for the hydrodynamic regulation of pH in disperse systems, which influence the surface charge of disperse particles, as well as the solubility of salts of heavy metals and their electrostatic adsorption and electromigration mobility are theoretically substantiated. Experimental verification of the developed theoretical model performe...
Article
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A hypothesis on the impact of water density at hydrophobic surfaces on the electrostatic component of their interaction is proposed. A theoretical model of the double electric layer and wedging pressure at variable density and consequently water permittivity has been developed. It was shown that reduction of permittivity at interphase surfaces dete...
Article
Theoretical analysis of the competing electromigration and hydrodynamic transport of OH-ions during the cathode chamber washing has been performed. The minimum washing rate preventing the penetration of OH-ions into soil has been determined. Fast pumping of the liquid allows us to replace the acidic solution used to neutralize OH-ions generated on...
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The profiles and velocities of electroosmotic flows at spherical and cylindrical metal surfaces are experimentally studied. Main differences are established between electroosmotic flows at the surfaces of ionite granules and particles with electronic conductivity.
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Photodestruction and adsorption of dyes in aqueous suspensions of nanopowders of titanium dioxide of anatase modification was studied. The photocatalytic activity of titanium dioxide nanopowders was examined in relation to the dispersity of particles and pH of the medium.
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Electroosmotic flow developing in a system of ionite granules is investigated. It is established that, at small intergranule distances, a rise in the number of granules decelerates the flow, while their contact reduces the flow velocity almost to zero.
Article
The paper presents a kinetic model developed for ozone dissolution in water and taking into account convective and diffusion processes occurring in the vicinity of floating bubbles that contain an ozone-air mixture. It was shown that the gradient of ozone concentration in a convective-diffusion layer and consequently the rate of ozone transfer from...
Article
An hypothesis regarding the impact of water density near hydrophobic surfaces on the electrostatic component of their interaction was offered. A theoretical model of the electric double layer and the interparticle interaction under conditions of the variable density and, consequently, variable dielectric permittivity of water has been developed. It...
Article
Conditions of soil pH regulation were analyzed and theoretically substantiated allowing us to increase the rate and degree of soil decontamination from heavy metals and radionuclides. Experimental testing of a theoretical model developed was conducted in the process of decontamination of kaolinite and a mixture of montmorillonite and sand. The obta...
Article
Both from the experimental and theoretical viewpoints it is of fundamental importance to know precisely which are the fluid flow characteristics in a (cylindrical, say) closed cell under the action of an externally applied electric field, parallel to the cell axis. This is so because in many cases the experimental determination of the electrophoret...
Article
Full-text available
Very small bubbles which partially coat the surface of particles influence whether or not heterocoagulation between a particle and a bubble occurs. The electrostatic and van der Waals forces of interaction between particles and bubbles were calculated as a function of electrolyte concentration, particle size, and the size and distributions of these...
Article
A theoretical model of the EOF established in a wide capillary after the application of a stepwise voltage has been developed. Both periodical and aperiodical flow regimes were studied with arbitrary pulse/pulse or pulse/pause durations and amplitudes. The numerical analysis performed for a few types of periodical regimes showed the peculiarities o...
Article
A theoretical model of the EOF and hydrodynamic flow in wide closed cylindrical capillaries, after the application of a stepwise voltage, is developed. Analytical expressions have been obtained as a sum of the solutions for the direct flow and backflow in both periodical and aperiodical regimes with arbitrary pulse/pulse or pulse/pause durations an...
Article
We have developed a model for water disinfection, which has taken into account convection-diffusion processes at the surface of emerging bubbles containing the ozone-air mixture and interaction of dissolved ozone with bacteria and ozone with organic impurities. Kinetic curves have been obtained for the concentration of dissolved oxygen, the degree...
Article
A study has been made of the interactions between non-deformed charged spherical droplets in concentrate emulsions. Based on Albers-Overbeek model, which was restricted to electrostatic effects, we calculate the repulsive interaction energy by taking also into account a quantity β that depends on the distance between the surfaces of the droplets an...
Article
Theoretical analysis of interparticle interaction in the presence of dissolved gases is carried out. It is shown that, depending on the type of interacting macrobodies and the location of gas inclusions, the van der Waals forces can change not only their values but even their sign. Regularities of change of interparticle interaction as a function o...
Article
Analysis of polarization processes at electrokinetic remediation of clay soils and evaluation of the contribution of various components into the transport of charged contaminants are performed. The peculiarities of soil decontamination at constant and pulse voltages are investigated using kaolinite and mixture of montmorillonite and sand contaminat...
Article
A study has been made of the interactions between non-deformed charged spherical droplets in concentrate emulsions.Based on Albers–Overbeek model, which was restricted to electrostatic effects, we calculate the repulsive interaction energy by taking also into account a quantity β that depends on the distance between the surfaces of the droplets and...
Article
Full-text available
Analytical solution to the system of differential equations describing the coagulation kinetics in Brownian dilute disperse systems is obtained. The effect of the reversibility of aggregation in the secondary minimum on the coagulation kinetics in the primary minimum is analyzed. It is shown that experimental conditions can substantially affect the...
Article
Full-text available
Electroosmosis of the second kind at the surfaces of one and two granules of a cationite and an anionite are studied by experimental methods. Dependences of the velocity of electroosmotic flow on the electric field strength, electrolyte concentration, and distance between the granules are measured. It is shown that the angular distribution and the...
Article
The electrostatic interactions in concentrate water-oil (W/O) emulsions, in which nondeformed droplets undergo electrostatic and Van der Waals interactions, were investigated. It was observed that as in W/O emulsion, the thickness of the electric double layer is of same order, such that the electrostatic energy was calculated with a correction fact...
Article
The physicochemical features of electrochemical decontamination of kaolinite slimes containing radionuclides (117Cs, 90Sr, and U) and heavy metals (Co) were studied. It is shown that the reagents-intensifiers (acetic acid, disodium ethylenediamine tetraacetate) are rather efficient in the decontamination process. The contribution of various compone...
Article
Theoretical model of concentration polarization in the system 'diaphragm-ionite' is developed and its influence on electroosmotic transport of liquid through the membrane is analyzed. Theoretical calculations are compared with experimentally measured velocities of electroosmotic flowing. Obtained results can be used for intensification of water pur...
Article
The simplest singlet–doublet emulsions (SDE) exhibit singlet–doublet quasi-equilibrium (s.d.e.) and slow coalescence between doublets. Orthokinetic coagulation and creaming may be eliminated using low-density contrast emulsions. The investigation of the evolution in time of the total number of droplet in such emulsions at SDE was recommended as a s...
Article
Full-text available
A two-stage thermochemical synthesis of colloidal-sized magnetic iron crystals is developed. Main dependences of magnetic properties of the obtained iron crystals on the composition of an initial solution and crystallization conditions are disclosed.
Article
The regularities of the influence of UV radiation on the process of ozone decomposition in water and air and on kinetics of ozone dissolution are analyzed. The kinetic model of organic compounds decomposition under joint action of ozone and UV radiation was developed. The kinetic curves of organic compounds degradation and a change of ozone concent...
Article
The kinetic model of ozone dissolution in water that takes into account convective-diffusion processes near the surface of bubble and the bulk reaction between ozone and organic substances was developed. The obtained kinetic curves of organic matter degradation and change of ozone concentration in water and ozone/air mixture were compared with expe...
Article
The peculiarities of droplet interaction and the possibility of their aggregation and disaggregation are analyzed for a dilute emulsion when the interaction between two droplets is not affected by the influence of other droplets. On the basis of Muller's model of dou-blet fragmentation, the characteristic time of this process (frag-mentation time τ...
Article
A theory of concentration polarization of a thin electrical double layer (DL) on a spherical particle is developed for the regime of large Peclet numbers which is realized in strong electric fields. In this regime, the concentration field arising outside DL is estimated under influence of diffusion and convection. According to the theory developed,...
Article
The conditions dependent on wetting film stability (WFS) for differeent flotation modes created by the enhancement of the particle bubble inertial interaction by the free movement of the bubble surfaces were studied. The modes of flotation dynamics were determine by the WFS which in turn effects the mechanism that control the flotation domain. The...
Article
The presence of dissolved gas, in the form of very small bubbles in the aqueous phase between a solid particle interacting with a microbubble, and/or on the surface of the particle, modifies the van der Waals interaction forces. The change in the character of the latter appears similar to the action of hydrophobic forces. Neglecting these changes c...
Article
Full-text available
The laws of the interaction between a gas bubble and a hydrophobic solid particle were studied. The range of the system parameters that can ensure the heterocoagulation of the particle and the bubble was determined.
Article
A theoretical model of the nonstationary concentration polarization of the diaphragm was developed. Both the electric field voltage at the diaphragm and electroosmotic flow rate were shown to depend markedly on the common polarization phenomena in the experimental cell. The theoretical and experimental time dependences of current and electroosmotic...
Article
Full-text available
The presence of dissolved gas, in the form of very small bubbles in the aqueous phase between a solid particle interacting with a microbubble, and/or on the surface of the particle, modifies the van der Waals interaction forces. The change in the character of the latter appears similar to the action of hydrophobic forces. Neglecting these changes c...
Article
The dynamics of the adsorption process at the surface of a growing bubble is described for a diffusion-controlled adsorption mechanism. The model is linked with the measuring procedure in maximum bubble pressure experiments as it is programmed in standard tensiometers. As a result the pressure– gas flow rate dependence is obtained which is the basi...
Article
Full-text available
Using the cell model approach, a distribution of the equilibrium electric potential is obtained within an electrolyte solution being the continuous phase of a concentrated disperse system. The distribution is a solution of the Poisson–Boltzmann problem for a spherical cell. A method, which was developed in earlier works of Dukhin, is employed to de...
Article
Whether or not a particle is captured by a rising bubble during flotation is determined, to a large degree, by the hydrophobic force of attraction. The origins of the latter force have remained obscure, despite the early insights of flotation scientists. Recent evidence indicates that the surface properties of the solid substrate, the type and conc...
Article
Full-text available
Nonstationary concentration polarization of membranes was analyzed theoretically. Desalination and transport of single- and double-charged ions through MK-40 cation-exchange membrane was studied in the stationary and pulse modes with the fixed voltage. Main generalities in the changes of the pH and conductivity of desalinated solution as well as co...
Article
The article focuses on the principles of strong concentration polarisation of flat and curved interfaces including the phenomenon of the limiting current. It is shown both theoretically and experimentally that electroosmosis of the second kind near the curved interface causes an important change of characteristics of concentration polarisation and...
Article
The processes of attachment and detachment of small or medium-sized particles to relatively large bubbles during microflotation are considered in terms of the heterocoagulation theory. Calculations are made for the conditions that the surface potentials are of similar sign and constant, that one of the surface potentials is small, that hydrophobic...
Article
Electrodialysis is an effective method of water desalination. However, the efficiency of the method is limited by the concentration polarization of the ion-exchange membranes. Applying an electric field with special pulse characteristics can diminish the effect of the concentration polarization. A theoretical analysis is carried out for galvanostat...
Article
An analysis of the adsorption process during the deadtime period in maximum bubble pressure experiments is performed. The adsorption dynamics is calculated for the actual surface area increase of a bubble in a surfactant solution, which depends on characteristic system parameters such as the length and diameter of the capillary and the surfactant's...
Article
Full-text available
The laws of heterocoagulation between a bubble and a dispersed particle were studied. The range of the system parameters that ensure the stability of the resultant aggregates was determined.
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The peculiarities of concentration polarisation of ion-exchange particles in the conditions of electrokinetic phenomena of the second kind are analysed. It is shown that the theoretical model of concentration polarisation has to include the process of water dissociation. The region of parameters that corresponds to the maximum manifesta-tion of wat...
Article
The flotation rate of particles of different size and with different contact angles, provided by surface modification of the surface of broken quartz particles, with single monodisperse bubbles was investigated. A monotonic increase of collection efficiency was observed with increasing particle size at high particle hydrophobicity where attachment...
Article
A theory for the coupling of flocculation, coalescence and floc fragmentation in dilute, polydisperse oil-in-water emulsions with narrow droplet size distributions is proposed. For the first time, the strong decrease in the total droplet concentration in dilute oil-in-water emulsions at singlet–doublet quasi-equilibrium and at negligible multiplet...