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Reverse-osmosis separation of an aqueous solution of aniline on a flat-frame reverse-osmosis installation was studied for two types of industrial polymeric membranes in relation to the concentration and pressure of the solution in the intermembrane channel. The behavior of the main kinetic characteristics of separation was analyzed and explained for different physical conditions of the process.

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The paper presents the results of experimental data on the kinetic characteristics of ultrafiltration tubular elements, such as the output specific flow, retention coefficient, diffusion permeability coefficient, distribution coefficient. To study the purification of milk whey, we used tubular ultrafilters BTU 05/2 with membrane material fluoroplast (F), polyethersulfone (PESF), polysulfone (PS). For theoretical calculation of the retention coefficient, output specific flux, diffusion permeability coefficient, distribution coefficient, mathematical expressions were developed and empirical coefficients were obtained. The developed mathematical expression describes the experimental data with good reliability. The obtained experimental and calculated data can be used with high reliability in calculating mass-transfer fluxes of substances through a semi-permeable membrane, as well as in engineering methods for calculating and predicting efficiency, and using membrane processes for concentrating serum. The protein concentration in real milk whey was determined by formol titration. On the basis of the studies carried out, the dependence of the growth of the output specific flow on pressure was established, that the optimal pressure for concentrating milk whey on the ultrafiltration membranes we have chosen is 0.25 MPa. For three types of ultrafilters, the experimental value of the coefficient was within 99% for protein. For the theoretical calculation of the retention coefficient, a program in the MAXIMA language was developed and registered. Due to the method of applying the membrane to the reinforcing element, the membrane material polyethersulfone (PESF) and polysulfone (PS) have a substrate, due to which they sorb more substances on themselves, because of this, the diffusion permeability coefficient and the distribution coefficient are much higher than that of a filter element with membrane made of fluoroplastic (F), which does not have a substrate.

This paper presents the analyzed results of the study of structural and kinetic characteristics of ion-exchange membranes MA-40, MK-40, PC Acid 60 and CM(H) (RALEX®) during separation and concentration of copper-containing solutions in the electrodialysis process. In particular, the sizes of amorphous and crystalline regions of the membrane material structure and the degree of crystallinity were determined, the retention factor of cation Cu2+ and anions NO3- and SO42- were calculated. It was found that for mA-40 and MK-40 membranes the structure of the membrane material changes during water saturation, what in turn can affect the kinetics of mass transfer through the membrane. In addition a low sensitivity of membrane material to mechanical and thermal loads under cyclic operating conditions is detected. This is confirmed by the coincidence of diffraction angles at which peaks of dry and water-saturated samples of membranes are observed, and by a non-significant change in the x-ray degree of crystallinity of the membrane material within 5-7% in the smaller side for water-saturated samples. The data, which were obtained during this work, indicate a relatively good cleaning of copper-containing solutions by electrodialysis from extraneous ions (NO3- and SO42-) at high values of Cu2+ cations concentration. In the initial section, slightly less than 90% of Cu2+ cations are retained, while NO3- and SO42- anions remain significantly less – about 16.7% and 25.7%, respectively. It should be noted that the most optimal parameters of electrodialysis are required for maximizing the efficiency of concentration.

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