Volume 14, Nº 4 (2024)

The problem of separation and recovery of volatile organic compounds (VOC) vapors is important both from the point of view of reducing the negative anthropogenic impact on the environment and from the point of view of resource conservation. The main classes of VOCs are, first of all, aliphatic, aromatic and oxygen-containing hydrocarbons. A significant source of VOC emissions of various natures are waste gas process flows (or off-gases) of petrochemical industries (polymerization processes, hydrotreating, isomerization, dehydrogenation, etc.). The capture and recovery of VOC vapors is implemented mainly using recovery technology and decomposition technology.

This review is devoted to a brief overview of modern technologies for the removal and recovery of VOCs from vapor-gas mixtures. The technology of membrane separation of vapor-gas mixtures, including promising membrane materials, is considered in detail. This technology allows for the selective separation of VOCs, and the purified main gas flow can be returned to the production cycle, if necessary, without additional preparation.

The rapidly developing field of portable energy sources requires the search and development of effective materials for such devices. To improve the safety of the most common metal-ion batteries (lithium- and sodium-ion), instead of a liquid electrolyte, it is proposed to use a gel-polymer electrolyte with unipolar conductivity based on a Nafion-like electrolyte (Inion), plasticized with aprotic solvents. The work presents the results of a study of the thermal stability, molecular structure and supramolecular packing, as well as ionic conductivity of the Inion membrane in lithium and sodium forms, plasticized with propylene carbonate, using methods of simultaneous thermal analysis, IR spectroscopy, small-angle X-ray scattering and impedance spectroscopy.

The use of cation-exchange membranes as polymer electrolytes in lithium metal batteries can inhibit dendrite formation during battery operation. Solvation of the membranes leads to an increase in ionic conductivity, but the mechanical properties, which also affect dendrite growth, are significantly degraded. In the present work, the mechanical strength and volumetric stability of Nafion®-117 membranes in Li⁺⁺ form solvated by a mixture of ethylene carbonate and propylene carbonate were improved by introducing nanosized zirconium dioxide particles into the membrane matrix by in situ method. It is shown that the introduction of 3.8 wt.% ZrO₂ leads to a ~28-fold increase in Young’s modulus compared to the unmodified membrane. At the same time, the volumetric stability of the membranes during solvation increases by ~3.4 times. However, the ionic conductivity of the membranes decreases after the introduction of dopant and is 3∙10^–⁴, 5∙10^–⁶ and 2.7∙10^–⁶ S/cm at 25°C for the membrane without dopant and containing 3.8 wt.% and 6.7 wt.% zirconium dioxide, respectively.

Color indication of anthocyanins, FTIR spectroscopy, measurement of surface contact angle values, determination of specific electrical conductivity, as well as voltammetry and parallel measurement of pH of desalted solutions were used to analyze the fouling characteristics of aliphatic (CJMA-3, CJMC-3) and aromatic (AMX-Sb, CMX-Sb) ion-exchange membranes used in electrodialysis tartrate stabilization of wine material. It has been shown that polyphenols form complexes with metal ions on the surface and in the subsurface layers of cation-exchange membranes, which do not interfere with the transfer of cations. Foulants affect the magnitude of limiting currents and enhance water splitting at the surface of all studied membranes, and also reduce the electrical conductivity of anion-exchange membranes. The use of a pulsed electric field instead of a continuous direct electric current, traditional for electrodialysis, weakens the negative impact of foulants on membranes’ electrical conductivity. These data can be useful for selecting membranes and current modes when carrying out electrodialysis tartrate stabilization of wine materials.