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The influence of the structure of the surface cellulose acetate layer on the transport characteristics of ultrafiltration composite membranes is considered using the methods of IR spectroscopy and of scanning electron microscopy. The amorphous phase of ultrafiltration cellulose acetate composite membranes is formed at a certain stage of the technological cycle of obtaining a composite membrane. IR spectra are presented where the forms of the absorption bands of valence vibrations of hydroxylic groups at ν = 3339.14–3366.2 cm–1 alter the asymmetry parameter from ~1 for an air-dry sample and to 0.79 for a water-saturated one, which allows the assertion of formation of volumetric supermolecular structure of a cellulose acetate layer of an air-dry sample by two types of hydrogen bonds and dipole–dipole interactions of carbonyl groups. The decrease of the asymmetry parameter to 0.79 of the absorption bands of hydroxylic groups and of the intensity of absorption bands of methyl groups by 2.56, 3.3, and 3.8 times in water saturated samples of membranes occurs because of the destruction of supermolecular structure and reorganization of hydrogen bonds between the active groups of cellulose acetate and molecules of water. The data obtained by the method of scanning electron microscopy allow one to note that the surface layer of ultrafiltration membranes has an asymmetric pore structure. The surface layer of a membrane can be divided into two components: a selectively permeable layer with pores of small size and a pore substrate, in which the pores increase in their diameter as they approach the substrate.

A comparative study of the application of membrane, electromembrane and electrobaromembrane technologies for various industries in the field of wastewater treatment and technological solutions is presented. The principle of classification of membrane separation processes is formulated. The characteristic periods of the solvent transfer stimulation were determined. Based on the experimental data obtained on the permeability of the solvent through the MGA-80P and MGA-95 membranes, empirical dependences are proposed that describe the kinetic characteristics of the dependence from transmembrane pressure and temperature effects.

The article presents the results of a study of mass transfer in the process of electrochemical extraction of iron, magnesium and manganese ions from technological solutions. Mathematical expressions are obtained, and numerical values of empirical coefficients are determined for theoretical calculation of specific outflow, retention coefficient, and average mass transfer coefficients of the electrochemical membrane process of separation of technological solutions. The dependence of concentration polarization on solution flow rate, pressure gradient, and concentration is analyzed.

A flat-chamber electrobaromembrane apparatus with improved design and technological characteristics for wastewater treatment and differentiated ion extraction from industrial water systems was developed. A method allowing the total working area of the anodic and cathodic membranes, the sizes of the anodic and cathodic outlet flows, and other parameters of the membrane process to be calculated was presented. The design and technological parameters of the chamber and electrobaromembrane apparatus as a whole were calculated.

The paper presents experimental study of physical water condition and mass transfer in cellulose acetate and dynamic semipermeable membranes by infrared spectrometric and hydrodynamic methods. The authors found that OH-groups of cellulose acetate form a nonequilibrium grid of hydrogen bonds between molecules and their fragments in the amorphous phase of the semipermeable membrane in the air-dried sample. The water molecules adsorbed on active —OH and —C = O groups, particularly in the amorphous phase, create additional negative charge on the molecules of cellulose acetate resulting from the orientation of the water dipoles, which leads to electrostatic repulsion of broken, stranded molecule fragments and straightening of polymer molecule while breaking intermolecular hydrogen bonds. Thermogravimetric studies to find out the structural organization of hydrogen bonds and water condition in the samples of the semipermeable polymeric MGA-95 membrane showed that at temperatures in the air-dry and water-saturated samples the membrane degradation process starts and ends with mass loss and endothermic effect. The research proves the fact of dynamic membranes formation on the ultrafilters from water starch solutions. Due to the changes in condition and volume of water in the dynamic layer of the membrane, it is possible to change kinetic coefficients, i.e. to regulate the process of baromembrane separation of industrial water solutions. Electro-kinetic characteristics of reverse osmosis semipermeable membranes were studied. The experimental curves of the potential depending on sorption of sodium bicarbonate by MGA-95 and LSA-100 membranes were obtained. The discrepancy between the calculated and experimental data did not exceed 10 %. The method devised for determining the membrane potential in the process of sorption of sodium bicarbonate can be used as a testing methodology of polymeric semipermeable membranes.