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A method is developed for calculating the values of concentration polarization during the separation of an aqueous solution containing anionic surfactants for ultrafiltration membranes with ideal and non-ideal rejection coefficients in a wide range of changes in the values of the diffusion Peclet number.

The kinetic and thermal processes occurring during the separation of model solutions using electrodialysis equipment have been investigated. The design drawbacks of the developed apparatus that can affect the efficiency and quality of the solutions separation have been revealed.

The electrodialysis method is used to recover iron, nickel and copper from waste water generated in the manufacture of printed circuit boards. The objects of study were ion-exchange membranes PC Acid 60 (PCCell GmbH) and CM (H) RALEX® (MEGA) and model solutions containing heavy metal ions (Fe3+, Ni2+, and Cu2+) and SO42– и NO3– anions. The time dependences of the retention coefficients of the Fe3+, Ni2+, and Cu2+ cations were constructed, the degree of treatment of the solutions to remove the SO42– и NO3– anions was determined, and the ion fluxes and ion transport numbers were calculated. On separating solutions containing one and all three salts of the target metals, the retention coefficients of Ni2+ and Cu2+ cations differ significantly, whereas those of Fe3+ cations, on the contrary, differ by no more than 2–3%. On separating a multicomponent three-salt solution, the retention coefficients of Ni2+ and Cu2+ cations are decreased in comparison with the corresponding values for single-salt solutions. For the purpose of exhaustive metal recovery, the electrodialysis separation of multicomponent solutions is the most efficient method, as applied to Fe3+ and Cu2+ cations.

The paper presents a mathematical description of the electrodialysis process of chemical industrial wastewater separation and the method of calculating some technological parameters of the electrodialysis apparatus, taking into account the Spiegler friction theory. A sample calculation of these technological parameters for the case of treatment of wastewater containing nickel ions is presented.

This study is devoted to the development of a mathematical model of electromembrane separation of copper-containing solutions in copper plating industry based on the solution of the Nernst–Planck and Poisson–Boltzmann equations. The model tracks the dependence of the volumetric permeate flows and solution concentration on the time of the electromembrane process. The mathematical model allows us to calculate the concentration at the outlet of the electromembrane apparatus, specific outlet flow of the solvent, and energy consumption for membrane separation of solutions. The equations of the model allow for mass transfer and solution flow hydrodynamics in the intermembrane channel. The adequacy of the mathematical model was verified by comparing the calculated and experimental data on the change in the concentration of the desired substance in the retentate relative to pressure at a constant current density.

A method of heat calculation of an electrodialysis device is presented. The paper presents the calculation of heat distribution on construction elements of an electrodialysis device on the example of separation of an aqueous CuSO4 solution. The method will be useful in the development and primary calculations of laboratory electrodialysis units.

A method for predicting and calculating friction coefficients and kinetic characteristics for electrodialysis separation of industrial solutions containing nickel ions was developed. Approximations for predicting friction coefficients that could then be used to calculate kinetic characteristics for electrodialysis separation of industrial solutions were obtained using the developed method. The discrepancy between experimental and theoretically calculated data was estimated in most instances at ≤ 5%, indicating that the developed method was acceptable for use.

Methodology allowing to calculate and analyze the current density, current output, working area of the membranes, the throughput capacity of the plant, the voltage expended on the electrodialysis process, the number of sections in the electrodialysis unit and a number of other parameters, important for separating industrial solutions and waste water of chemical industries, is proposed in this paper. It is estimated that the calculated process parameters correspond to the data obtained during laboratory studies within ±10 %.

A comparative analysis of the structural evolution of MGA-95 and ESPA1 polymer composite porous films is performed by plotting the radial distribution functions of atoms using empirical X-ray scattering intensity curves and the thermophysical parameters of melting are calculated using data from differential scanning calorimetry (DSC). In the case of the water-saturated MGA-95 sample, the atomic density in the first coordination sphere of the cellulose acetate macromolecule is shown to decrease due to the breaking of intramolecular hydrogen bonds. The atomic density of coordination spheres with radii corresponding to the lattice parameters decreased suggesting spatial disorder of the macromolecules. The DSC data for the MGA-95 film (the enthalpies of melting of the dry and water saturated samples are ΔH = 8.57 and 6.55 J/g, respectively) suggests that sorption of water molecules leads to a decrease in the degree of crystallinity due to a change in the crystalline fractions in the polycrystals. In the case of the ESPA1 composite film, a decrease in the radius and an increase in the atomic density of the first coordination sphere are indicative of the orientational disorder of amorphous phase molecules upon the sorption of water. The appearance of additional coordination spheres with R2 = 3.88 and R3 = 5.26 A in the swollen ESPA1 sample suggests the quantitative redistribution of crystal phases in the substrate material. A detailed analysis of endothermic peaks on the DSC curve shows that the ratio of low- and high-temperature phases varies from 64% : 36% in the dry sample up to 51% : 49% in the water saturated sample at almost identical enthalpies of melting of ΔH = 12.18 and 11.66 J/g, respectively.

A membrane separation of solutions, along with other purification methods, plays an important role in the effective and ecological safety of food production enterprises and is used for softening and demineralization of water, separation, concentration and purification of technological solutions, as well as for other processes. An important problem of membrane and electromembrane separation methods is to increase the used membrane selectivity. Therefore, the aim of this work was to study the structure transformation effect of ion-exchange membranes on a separation processes efficiency of technological solutions and an ecological safety of food production enterprises using the methods of X-ray diffraction analysis and differential scanning calorimetry (DSC). The analysis of the calculated values of crystallinity degree (CD) by X-ray diffractograms allowed us to identify the different effect of water saturation on the studied membranes. The structure of their material changes, which in turn affects the transport characteristics of the membranes, the efficiency of separation and, ultimately, the environmental ecological safety food enterprises. The cation-exchange membrane MK-40L was characterized by an increase in CD by 5.83%, and the anion exchange membrane MA-41P on the contrary was characterized by a decrease in CD by 5.87%. The crystallite sizes were distributed in the range of 0.096-0.345 nm for the MA-41P membrane and 0.096-0.193 nm for the MK-40L membrane. During thermal studies by DSC one endothermic and exothermic sections were revealed on the obtained curves in the temperature range of 30-202 and 202-498 °C for the MK-40L membrane and 30-223 °C and 223-498 °C for the MA-41P membrane, respectively. The endothermic sections of the curves were characterized by one endothermic peak. Four or five pronounced exothermic peaks were registered on the exothermic sections. At the same time, the MK-40L membrane was characterized by more intense peaks in a water-saturated sample and the MA-41P membrane in the dry one.

The paper examines the specific output stream and the rate of detention of a semi-permeable ultrafiltration membranes, UPM, UAM150, UAM200 in the separation process, waste starch and syrup production JSC., the company "Krakhmaloprodukt" low-pressure baromembrane method. As a result of the analysis of experimental data, the dependence of the retention factor of ultrafiltration membranes UPM-K, UAM150, UAM20 at different concentrations of the dissolved substance was obtained and analyzed. For the theoretical calculation of the process of ultrafiltration separation technology solutions of starch and syrup production modified mathematical expression for the factor of detention and the specific output stream and the numerical values of the empirical coefficients. Ultrafiltration for the separation of waste starch and syrup production the technological scheme of purification, separating the main elements of which was the pre-filter, biofilter, cascade ultrafiltration apparatus, centrifugal and plunger pumps, as well as the adsorption column.The application expediency of the selected apparatus with flat chambers lies in the simplicity of their production technology and in the self-selection possibility of optimum type membranes. It is possible in the presented apparatuses to usemembranes of different types and in the course of the evaluation experiment to establish to what extent they correspond to the most important technological parameters of the process, such as specific output flow, retention factor and resistance to pollution. It is noted that the specific output flow of ultrafiltration membranes decreases with the increase of the initial concentration of the dissolved substance, as the viscosity of the solution increases and its osmotic pressure increases, and the decrease in the retention factor of ultrafiltration membranes is caused by the formation of diffusion boundary layers on the active layer of membranes.

An electroultrafiltration apparatus with flat chambers and a method for calculating the number of devices required for efficient separation of solutions, heating power, amount of heat, and total energy required for electroultrafiltrational demineralization and concentration of a protein in industrial solutions from biodegradable plastics production were designed.

Design of a flat-chamber type of electrobaromembrane device and procedure for calculating permeate flow rate and increased effective membrane area are developed for cleaning chemical, engineering, and food industry process solutions.

This work is devoted to the study of specific solvent stream in baro membrane separation processes in the biochemical industry. The main indicators, which characterize baromembranes technology, are productivity and quality division. Performance of baromembrane separation is estimated by the specific output or specific solvent stream, which is equal to the permeate flow per unit working area of the membrane per unit of time, and also determines the speed of the process of baromembrane division. This parameter depends on the material of the membrane, the nature of the solutes and their concentrations in the solution, the operating pressure, temperature and hydrodynamic processes. The article analyzed the specific solvent flow, which mathematically described by the equation based on Darcy's Law. This law establishes proportional dependence on the driving force of the process, the concentration and type of membrane. For the research was used following technique. The initial stage was to preliminary cleaning of membranes from impurities, checking the integrity of individual units, launching in work mode for a time period of 18 hours. Then there was a preliminary experience for the establishment of a permanent performance with a factor of retention membranes. After that was done a series of basic experiments, the results of which were used for calculate of specific solvent stream. As a result of investigations made certain conclusions. Specific solvent stream decreases with increasing concentration. In ultrafiltration membranes the specific solvent stream is higher than in reverse osmosis membranes. This phenomenon depends on the type of membrane. When the pressure increases the flow of the solvent and performance of baromembrane separation of solutions increases too. Specific solvent stream are influenced by concentrating polarization, gelation and sedimentation, which are formed as a result of increasing pressure and adsorption on the membrane surface.

Electrodialysis (ED) is applied in different fields of industry (Strathmann 2010). It has found wide application in water and wastewater treatment, stabilization of wine, whey demineralization and also for recovery of valuable components associated with the depuration of wastewater. New treatment processes can be designed by integration with other membrane processes as well as nanofiltration an reverse osmosis. Aim of the work is the study of electrodialysis process with some model salt solutions and the attempt to apply it to some industrial wastewater. Electrodialysis tests were mainly performed using model solutions containing nitrates, ammonia or metals. Few tests have been carried out on some real effluents as coke oven wastewater or olive mill wastewater, which were treated in the electrodialysis plant after reverse osmosis concentration. In the present paper some results about the ED treatment of solution containing high copper concentration will be shown.