Том 1, № 1 (2019)

The paper presents the results of the development of a unit for calculating mass transport in a membrane gas separation apparatus in the Aspen Plus environment. The created user model has been verified by comparing the results of the calculation of separation characteristics with available experimental data for two cases. In the first case, the calculation results were compared with experimental data on the separation of the ternary H₂O/EtOH/N₂ (13.3/5.5/81.2 mol %) vapor–gas mixture simulating the stream from the stripping column of a laboratory membrane vapor separation unit with a plate-and-frame membrane module for ethanol recovery from fermentation broth. It has been shown that the calculated concentrations of the components in the retentate and permeate streams are close to the experimental values obtained in the separation of the ternary vapor–gas mixture. In the second case, the calculation results were compared with experimental data obtained upon the separation of a binary N₂/CH₄ gas mixture (99/1 mol %) simulating a stream with a low content of an easily penetrating impurity component using a radial membrane module. It has been found that the calculated concentration of CH₄ in the retentate is noticeably less than in the experiment, especially at high stage cuts, a difference that is associated with the increasing influence of the longitudinal mixing of components at low speeds of the mixture in the channels of the membrane module, which deteriorates the separation characteristics of the apparatus with respect to the removal of impurities and requires additional consideration of the deviation from the plug-flow mode in computational mathematical models used for this case.

Membrane technologies, in particular, electrodialysis, are increasingly being used to stabilize and condition juices and wines. This work is aimed at finding environmentally appropriate “mild” methods for regeneration of anion-exchange membranes that are used in these processes. It has been shown that the fouling of anion-exchange membranes by grape wine components leads to an increase in both their electrical resistance by 30 or more times and thickness. The behavior of the resistance and its values in grape juice and wine for the investigated membranes are similar, apparently, due to the similar chemical composition of these liquid media. Treatment with NaCl solutions leads to partial degradation of the formed colloidal particles as a result of to the salting-out effect. The higher the salt concentration in the regenerating solution, the closer the conductivity values of the regenerated membranes are to the original values. The thinner the membrane and the larger its pores, the faster and more complete the regeneration process. If the contact time of anion-exchange membranes with wine does not exceed 70 h, salt regeneration can almost completely restore their selectivity. For example, in the case of homogeneous AMX-Sb membrane, the transport numbers of the counterion Cl⁻ in the initial and regenerated samples differ by no more than 1%. In the case of heterogeneous MA-41P membrane, this difference increases to 3%.

The optical properties of track-etched membranes, obtained by irradiating a poly(ethylene terephthalate) film on a synchrotron through a mask with regularly spaced holes of 1 μm in diameter and subsequent chemical etching, have been investigated. These objects can be used as a template for fabricating regular plasmon resonance systems and two-dimensional photonic crystals.

The modification of a nylon microfiltration membrane with silver compounds for the disinfection of drinking water under dynamic conditions has been carried out, and the antibacterial properties of the modified membranes have been studied. It has been revealed that the initial microfiltration membrane is not capable of complete removal of microorganisms from water. It has been determined that membrane modification with the silver compounds leads to the complete disinfection of the water. In this case, the modification does not lead to a significant decrease in the specific productivity of the membranes. Insoluble silver salts are distributed on the membrane surface in the form of particles from 0.1 to 5 μm. Depending on the type of the silver compound used for the treatment of membranes, the silver content ranges from 5.11 to 9.06 wt %. The most uniform distribution of silver over the entire membrane surface and the maximum content are achieved by treating the membrane with an AgNO₃ solution.