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BIOPHYSICS (53 journals)

Showing 1 - 52 of 52 Journals sorted alphabetically
Acta Biochimica et Biophysica Sinica     Hybrid Journal   (Followers: 5)
Advanced NanoBiomed Research     Open Access  
Annual Review of Biophysics     Full-text available via subscription   (Followers: 24)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 17)
BBA Advances     Open Access   (Followers: 4)
BBA Bioenergetics     Hybrid Journal   (Followers: 5)
BBA Biomembranes     Hybrid Journal   (Followers: 11)
Biochemical and Biophysical Research Communications     Hybrid Journal   (Followers: 17)
Biochemistry and Biophysics Reports     Open Access  
Biochimica et Biophysica Acta (BBA) - General Subjects     Hybrid Journal   (Followers: 12)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 6)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 12)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 10)
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics     Hybrid Journal   (Followers: 11)
Bioinspired, Biomimetic and Nanobiomaterials     Hybrid Journal   (Followers: 3)
Biophysical Chemistry     Hybrid Journal   (Followers: 8)
Biophysical Journal     Hybrid Journal   (Followers: 46)
Biophysical Reports     Open Access   (Followers: 5)
Biophysical Reviews and Letters     Hybrid Journal   (Followers: 5)
Biophysics     Hybrid Journal   (Followers: 8)
Biophysics Reports     Open Access  
BMC Biophysics     Open Access   (Followers: 4)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 6)
Current Topics in Biophysics     Open Access   (Followers: 2)
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 1)
European Biophysics Journal     Hybrid Journal   (Followers: 4)
Food Biophysics     Hybrid Journal   (Followers: 3)
Freshwater Biology     Hybrid Journal   (Followers: 31)
GSTF Journal of BioSciences     Open Access  
IEEE Life Sciences Letters     Hybrid Journal  
IEEE Nanotechnology Express     Hybrid Journal   (Followers: 18)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 3)
International Journal of Biochemistry and Biophysics     Open Access   (Followers: 1)
International Journal of Biophysics     Open Access  
Journal of Biopharmaceutical Statistics     Hybrid Journal   (Followers: 23)
Journal of Biophotonics     Hybrid Journal   (Followers: 1)
Journal of Biophysical Chemistry     Open Access   (Followers: 3)
Journal of Biophysics and Structural Biology     Open Access   (Followers: 2)
Journal of Medicine, Physiology and Biophysics     Open Access  
Journal of Physical Chemistry & Biophysics     Open Access  
Membranes and Membrane Technologies     Full-text available via subscription  
Nanomedicine Research Journal     Open Access  
Nanomedicine: Nanotechnology, Biology and Medicine     Hybrid Journal   (Followers: 5)
Natural Products and Bioprospecting     Open Access   (Followers: 2)
Nature Communications     Open Access   (Followers: 310)
PMC Biophysics     Open Access  
Progress in Biophysics and Molecular Biology     Hybrid Journal   (Followers: 1)
Progress in Physical Geography     Hybrid Journal   (Followers: 11)
Quarterly Reviews of Biophysics     Hybrid Journal   (Followers: 3)
Radiation and Environmental Biophysics     Hybrid Journal   (Followers: 3)
Research & Reviews : A Journal of Life Sciences     Open Access  
Statistics in Biopharmaceutical Research     Full-text available via subscription   (Followers: 15)
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Membranes and Membrane Technologies
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ISSN (Print) 2517-7516 - ISSN (Online) 2517-7524
Published by Springer-Verlag Homepage  [2537 journals]
  • MF-4SC Membranes Modified by Polyaniline for Potentiometric Determination
           of Saccharin and Sodium Ions in Aqueous Solutions

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      Abstract: ― MF-4SC membranes have been modified by polyaniline (PANI) with the oxidative polymerization method. The influence of the method of obtaining hybrid membranes and the content of PANI in them on the value of IEC, water uptake, and transport properties have been investigated. The characteristics of DP‑sensors (DP is Donnan potential) based on the obtained membranes in aqueous solutions containing saccharin and sodium ions at pH < 7 have been established. It is found that appearance of additional sorption centers in the form of amino groups and fragments with π-π conjugation when introducing PANI to membranes promotes the increase in the sensitivity of DP-sensors to saccharin ions. The use of MF-4SC/PANI membranes obtained by various methods makes it possible to reduce the correlation between the cross-sensitive DP-sensors responses and provides high accuracy of the simultaneous determination of saccharin and sodium ions in aqueous solutions.
      PubDate: 2021-11-01
       
  • Mathematical Modeling of Turbulent Transport of Particles in the Boundary
           Layer of a Tubular Membrane Element

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      Abstract: The paper deals with the problem of adapting the theory of turbulent transport of microparticles from the flow core to the surface of a tubular membrane during the separation of dispersed systems by ultrafiltration. The sizes of microparticles that are the most susceptible to transport have been determined. Mathematical models are proposed for determining the coefficient and intensity of turbulent deposition. Experimental data have been obtained that confirm the presence of particles, the sizes of which are most susceptible to deposition on the walls from the flow core by the example of ultrafiltration of spent engine oils.
      PubDate: 2021-11-01
       
  • Biomimetic Membranes without Proteins but with Aqueous Nanochannels and
           Facilitated Transport. Minireview

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      Abstract: Imitation of biological membranes and aqueous channels attracts more and more attention. In this review, we mention both the early and very recent papers in this area. Still, we concentrate our attention on less known biomimetic membranes, which are commercial nitrocellulose ultrafilters, impregnated by esters of fatty acids. Pores in filters are filled with lipid-like oils, but aqueous nanochannels are spontaneously formed on the inner pore surfaces with carboxylic groups fixed on nitrocellulose. This combination imitates the most fundamental barrier properties of biological membranes, including specific (per unit thickness) permeability of respiratory gases, transport of nonelectrolytes, water, and ions, cation/anion selectivity, electric impedance, etc. The activation energy for water transport in nanochannels is similar to that in aquaporin. In the presence of fatty acids and other carriers, it is possible to observe facilitated and coupled active counter transport of different metal cations in exchange to H+ and without any transmembrane pressure, voltage or ATP. When quinones are dissolved in oils, light-sensitive co-transport of electrons and H+ through oil is possible. In this case, redox-active substances are separated by the membrane. They are not mixed, but they still react. Small biomimetic membranes can be used as electrochemical drug sensors in drug detection and screening, medium size membranes—for smart transdermal drug -delivery, and large membranes—for industrial separation and purification. For example, after small modifications, they can be used for metal recovery, including radioactive strontium removal from nuclear waste accumulated and stored since the Cold War.
      PubDate: 2021-11-01
       
  • Composite Membrane Based on Track-Etched Membrane and Chitosan
           Nanoscaffold

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      Abstract: ― A method has been developed for modifying a polyethylene terephthalate (PET) track-etched membrane (TM) with a chitosan nanoscaffold to create a new composite membrane with individual properties. To provide increased adhesion and obtain a uniform nanoscaffold chitosan layer, a specially developed TM with an electrically conductive titanium layer was used as a counter electrode of the collector. The effect of solvent in the spinning solution on the chitosan nanoscaffold is considered. Thermal and chemical crosslinking was used to stabilize the chitosan nanoscaffold. The surface morphology of the composite membrane has been analyzed using scanning electron microscopy. The water and gas permeabilities of the composite membrane have been studied. The electrokinetic characteristics of the composite membrane have been investigated depending on the pH of a 0.01 M KCl solution, and the strength characteristics of the composite membrane have been studied. It has been shown that the resulting composite based on TM with titanium and chitosan nanoscaffold can be a platform for the fabrication of membrane-sorption materials.
      PubDate: 2021-11-01
       
  • Modeling of Film Distillation with Membrane Condenser for Treatment of
           Reverse Osmosis Concentrate under Vietnam Tropical Conditions

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      Abstract: This work is aimed at investigating a new process of film distillation with a membrane condenser (FDMC) for obtaining fresh water from a reverse osmosis concentrate. The behavior of a number of structural materials during their exposure for 4.5 months in the open air and in sea water has been investigated. In the Simulink/MATLAB program, a model of the FDMC unit with the possibility of using solar radiation as a renewable energy source has been built. The operation of the unit for one month was simulated and it was shown that the area of solar collectors has the greatest influence on the volume of water received during a month of operation. The area of the evaporator has little effect on the overall process performance, but it can reduce the initial costs while maintaining the same payback period. Modeling showed that the recovery of distilled water decreases by 2–3% (from ~71–72 to ~69%) with a decrease in the NaCl concentration of the output stream from 26 to 24 wt %. The mode with a lower concentration of the output solution was found to be optimal due to the absence of both the risk of pipeline clogging and the need for frequent flushing of the evaporating surface. The use of data on solar radiation for the most and least sunny months (April and November, respectively) shows a nonlinear drop (by 46–47%) in productivity for water, which is explained by both nonlinearity of the temperature dependence of water vapor pressure and a nonlinear relationship between the solar collector efficiency and radiation intensity and ambient temperature. Varying the temperature of the cold circuit shows that using a lower temperature increases the water productivity by 5–15%, while keeping the water recovery rate constant.
      PubDate: 2021-11-01
       
  • Perovskites Based on SrCo0.8Fe0.2O3 – δ (SCF) and
           Ba0.5Sr0.5Co0.8Fe0.2O3 – δ (BSCF) Oxides and Their Application as
           Membrane Materials and Electrodes for Solid Oxide Fuel Cells

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      Abstract: This review describes perovskites based on SrCo0.8Fe0.2O3 − δ (SCF) and Ba0.5Sr0.5Co0.8Fe0.2O3 − δ (BSCF) oxides, which are thought of as promising materials for catalytic membrane reactors and solid oxide fuel cells (SOFCs). Data on the oxygen permeability of disk-shaped and microtubular membranes based on SCF and BSCF oxides are discussed; special attention is paid to methods used to increase the oxygen permeability of membrane materials and improve their phase/structural stability. The review describes the electrochemical characteristics of promising cathode materials based on SCF and BSCF perovskites and provides a summary of the latest developments.
      PubDate: 2021-11-01
       
  • Peculiarities of Butane Transfer in Poly(4-Methyl-1-Pentene)

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      Abstract: The features of the butane transfer through homogeneous membranes 40–50 μm thick based on poly(4-methyl-1-pentene) (PMP) of various crystallinity degrees have been investigated in the temperature range from 10 to 80°C. It has been shown that in this temperature range, including Tg of the polymer, for continuous PMP membranes obtained by the melt technology there is a significant influence of butane activity, which was previously described in the literature for composite membranes based on PMP with thin selective layers formed from solutions. It has been noted that the degree of crystallinity of PMP has a significant effect on the permeability. Based on the experimental data, the temperature parameters have been calculated taking into account the exponential form of the dependence of permeability on the butane activity. Temperature dependences have been obtained in the absence of the influence of butane on the polymer, which have a nearly linear form in the Arrhenius coordinates, while practically coinciding for samples with different degrees of crystallinity.
      PubDate: 2021-11-01
       
  • Gas Transport and Separation Properties of Polynorbornene Treated with
           Elemental Fluorine in a Perfluorodecalin Liquid

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      Abstract: Surface modification of metathesis-based polynorbornenes (PNB) has been performed by means of direct fluorination. The treatment has been conducted in a flow type reactor in perfluorodecalin medium by fluorination mixture (4.9 vol % F2 + N2) for 30, 60, 120, and 240 min. Virgin and treated PNB films have been investigated by X-ray diffraction, IR spectroscopy, scanning electron microscopy (SEM), and X-ray energy dispersive spectroscopy (XEDS). The surface fluorination of PNB has been shown not to change location of broad reflexes on X-ray powder diffraction patterns and the samples retain amorphous nature. SEM and XEDS have demonstrated laminate structure of treated films and have shown gradual increase of the thickness of the fluorinated layers up to 6–7 µm according to both second electron contrast and concentration profile of fluorine. However, a slight decrease of thickness for the film fluorinated for 240 min has been observed that can be explained by its partial dissolution in the perfluorinated medium. IR spectroscopy has shown (i) an increase of concentration of fluorine- and oxygen-containing groups in the surface layers with increase of fluorination time and (ii) the fluorination is predominantly realized via hydrogen atoms at cis-C=C bonds of norbornene chain. The study of the gas transport and gas separation properties of surface-fluorinated PNB films has shown that the greatest modification effect is manifested for PNB films fluorinated for 30 min, while a further increase in the processing time (up to 240 min) does not lead to an improvement in the effective coefficients of permeability and separation selectivities. Similar patterns have been observed when studying the separation of model gas mixtures (He + CH4 and CO2 + CH4) for surface modified PNB films. At the same time, the separation factors increased from 13 to 47 for a He–CH4 mixture and from 12 to 23 for a CO2–CH4 mixture.
      PubDate: 2021-11-01
       
  • Parameters of Household Wastewater Treatment Using Composite Membranes
           with a Surface Layer of Cellulose Acetate

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      Abstract: Composite membranes based on nylon and cellulose acetate (CA) are synthesized by immersing a microporous nylon substrate into a 3% CA solution in acetone. The CA content in the membrane is 12–53% depending on the number of deposited surface layers. The results of studying the properties of the composite membranes show that the water uptake and total porosity of the membranes decrease with an increase in the number of CA layers; this finding is attributed to the compaction of the membrane structure. In addition, it is revealed that the contact angle of the membrane increases by 6.4°; this means that the hydrophilic properties of the membrane decrease. The deposition of the surface layer of CA leads to the smoothing of the porous and rough surface of the nylon membrane base and a decrease in the porosity. Tests on household wastewater treatment using a nylon–CA3 composite nanofiltration membrane are conducted. It is found that the specific flux of the nylon–CA3 membrane with respect to wastewater is 39.7 dm3/(m2 h) at a pressure of 0.7 MPa. According to the results of the study, it is determined that the average degree of purification using the nylon–CA3 membrane is 64.5%. The nylon–CA3 membrane exhibits a high selectivity for multivalent ions (70%) and a high degree of purification in terms of COD and BOD5 (~92%), which is not inferior to the characteristics of a commercial nanofiltration membrane.
      PubDate: 2021-11-01
       
  • Biomimetic Membranes with Aqueous Nanochannels. Phase Transitions and
           Oscillations

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      Abstract: Fatty acids in pores of nitrocellulose filter may be either in a gel or liquid crystal state. At the melting point, we observe large spontaneous oscillations both of transmembrane voltage and current. The effect is observed even when the membrane separates two aqueous solutions with the same composition. The relation with the Second Law of thermodynamics and the possibility of using the effect for electric energy generation is mentioned.
      PubDate: 2021-11-01
       
  • Preparation, Structure, and Properties of Track-Etched Membranes Based on
           Polylactic Acid

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      Abstract: New applications, in particular in medicine, require the creation of track-etched membranes (TMs) with fundamentally new properties. There are well-known TMs made from polycarbonate, polyimide, polypropylene, polyethylene terephthalate, polyethylene naphthalate, and polyvinylidene fluoride; that is, polymers characterized by high chemical resistance. This study focuses on the development of a membrane made of the biodegradable polymer polylactic acid (PLA). Films prepared from a 1% solution of polylactic acid with a molecular weight of Mw = 121000 g/mol were taken as the initial matrix for TM fabrication. The films were irradiated with 1.2-MeV Xe ions at a fluence of 3.1 × 107 cm−2 on an IC-100 cyclotron. Etching was carried out in NaOH solutions of various concentrations (0.1, 1, or 2 mol/L) with varying the temperature from 18 to 70°С and the treatment time from 5 to 30 min. It has been revealed that the optimal treatment conditions for irradiated PLA films are etching in 1 M NaOH at a temperature of 44°C. This mode, with a time variation from 10 to 30 min, makes it possible to obtain through pores with a diameter of 0.6 to 1.5 µm with channel geometry close to cylindrical. It has been found that an increase in the etching time over 20 min leads to a decrease in the roughness of both membrane sides.
      PubDate: 2021-09-01
      DOI: 10.1134/S2517751621050073
       
  • Stability of Properties of a Modified Anion-Exchange Membrane Obtained by
           Treating the Surface of a Commercial Sample with Bifunctional Polymer
           Containing Quaternary Amino Groups

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      Abstract: Modification of commercial ion-exchange membranes is the easiest and cheapest way to improve their properties. It has been shown that the treatment of the surface of the MA-41P membrane with a bifunctional polymer (copolymer based on polydiallyldimethylammonium chloride) not only reduces the generation of H+ and OH– ions but also contributes to an increase in the limiting current density and a reduction in the length of the current-voltage curve plateau compared to the initial membrane. These changes are signs of increased electroconvection at the surface of the modified membrane (MA-41PM). It has been found that the modified membrane exhibits stability for at least 100 h of operation in an overlimiting current mode. In an electric field, a partial separation of the modifier from the MA-41PM surface takes place as a result of which the rate of generation of H+/OH– ions gradually increases.
      PubDate: 2021-09-01
      DOI: 10.1134/S2517751621050036
       
  • The Utilization of Highly Mineralized Liquid Waste from a Chemical
           Desalination Water Treatment Plant of a TPP with the Generation of
           Electrical Energy by Reverse Electrodialysis

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      Abstract: Reverse electrodialysis (RED) technology is one of the promising directions of alternative energy based on electrochemical transformations. In this study, an industrial experiment on the utilization of highly mineralized alkaline liquid waste from a chemical desalination water treatment plant by RED technology is performed on an experimental pilot electromembrane unit at an operating TPP. The RED process with ion-selective cation- and anion-exchange membranes proceeds in the diffusion dialysis mode under the action of the concentration gradient of ionic current carriers. As a result, the specific power of the unit per unit area of the membrane pair of 0.36 W/m2 is recorded. The rate of diffusion dialysis transport of the electrolyte substance is 0.3–0.6 kg/h on average per an apparatus. The efficiency of the RED process with respect to the energy generation is 47%, the theoretical electromotive force is 0.12 V per chamber, and the potential energy storage (specific generated energy) is 1.8 kWh/m3 of highly mineralized liquid waste at f = 1/2.
      PubDate: 2021-09-01
      DOI: 10.1134/S251775162105005X
       
  • Influence of Protonation–Deprotonation Reactions on the Diffusion of
           Ammonium Chloride through Anion-Exchange Membrane

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      Abstract: Electrodialytic concentration of ammonium-containing liquid products of biochemical processing of municipal, industrial, and livestock wastewater is a promising method for obtaining cheap liquid fertilizers for agriculture. At the same time, it is known that electrodialysis of NH4Cl solutions fails to achieve the same high brine concentrations as in the case of other chlorides, for example, KCl. We show that the reason is high diffusion permeability of anion-exchange membranes (AEMs) to NH4Cl, which is due to the protonation–deprotonation reactions of ammonium coions during their transfer from an external solution to an internal AEM solution and vice versa. For the first time, a mathematical model of NH4Cl diffusion through AEM was proposed with allowance for these reactions. The experimental values of the diffusion permeability of an anion-exchange membrane AMX and a cation-exchange membrane CMX in NH4Cl and KCl solutions have been compared. between The results of calculating the diffusion permeability of the membrane AMX in NH4Cl solutions are in qualitative agreement with the experiment data.
      PubDate: 2021-09-01
      DOI: 10.1134/S2517751621050085
       
  • Production of High-Purity Hydrogen by Steam Reforming of Associated
           Petroleum Gas in Membrane Reactor with Industrial Nickel Catalyst

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      Abstract: The features of steam reforming of a hydrocarbon mixture containing 71.8% СН4, 15.6% С2Н6, 10.2% С3Н8, and 2.4% С4Н10 in a membrane reactor with a 30 μm thick Pd–Ru alloy foil and the NIAP-03-01 industrial nickel catalyst have been investigated. The reaction was studied in the temperature range of 723–823 K at a steam/feed ratio of 5 and space velocities of 1800 and 3600 h−1. Comparison with the “nonmembrane” reaction showed that in the membrane reactor, the feedstock conversion to form H2 and CO2 increases and the yield of byproduct methane and carbon deposits decreases. With an increase in the rate of H2 recovery from the reaction mixture by permeate evacuation, the degree of conversion by the water gas shift reaction yielding H2 and CO2 increases. Under optimal conditions (773–823 K, 1800 h−1, permeate evacuation), high purity H2 is formed in an amount of about 0.8 mmol/(min gcat) and more than 80% of H2 is recovered from the reaction mixture. As the feed space velocity increases to 3600 h−1, the yield of hydrogen increases to 1.3 mmol/(min gcat) and 90% of H2 is recovered through the membrane. However, a high conversion of the feedstock into carbon deposits is observed in this case. In general, the results obtained show that it is possible to obtain high-purity hydrogen from associated petroleum gases by optimizing the conditions of steam reforming in a membrane reactor without preliminary isolation of C2+ alkanes from the feedstock.
      PubDate: 2021-09-01
      DOI: 10.1134/S2517751621050048
       
  • The Separation of Highly Mineralized Effluents Using Nanofiltration
           Membranes to Facilitate Their Further Utilization

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      Abstract: The problems of treatment of various mineralized effluents with the use of reverse osmosis and nanofiltration are considered. It is noted that concentrates from reverse osmosis plants, which have high concentrations of salts and organic substances and are difficult to utilize cause a serious environmental problem. It is proposed to use the separation of the concentrates to solutions containing their components depending on the value of their rejection using nanofiltration membranes. Thus, the concentrates from reverse osmosis plants after the treatment of wastewater, sludge water after dewatering of sludge, as well as concentrates from the municipal solid waste (MSW) landfill leachate treatment plants can be separated to solutions with a high concentration of organic substances and salines (containing ammonium salts), the volumes of which are 10–20-fold lower than the volumes of concentrates. It is demonstrated by way of example of the effluents from ion exchange softening plants, which are a mixture of sodium and calcium chlorides, how multicomponent solutions can be separated to highly concentrated solutions of sodium chloride and calcium chloride to reuse sodium chloride and purified water in production. A technology of separation of solutions is described, which utilizes the dilution of the concentrate with deionized water, which makes it possible to achieve the separation of the solutions to the components depending on their selectivity—the degree of their rejection by nanofiltration membranes.
      PubDate: 2021-09-01
      DOI: 10.1134/S2517751621050097
       
  • Influence of Titanium Dioxide Particles Percentage in Modifying Layer on
           Surface Properties and Current-Voltage Characteristics of Composite
           Cation-Exchange Membranes

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      Abstract: Ion-exchange membranes are widely used as a key element in electromembrane processes, in particular, in the electrodialysis processing of solutions for wastewater treatment, the production of valuable medicinal and nutritional products, and many other applications. One of the main limiting factors in the development of electromembrane technologies is a low rate of mass transfer. A solution to this problem can be intensification of electroconvective mixing of the solution at the membrane surface by surface modification. Samples of composite membranes were prepared by forming a modifying film of perfloursolfonic acid polymer with the embedded TiO2 particles of the various percentage on the surface of a heterogeneous cation-exchange membrane MK-40. It has been shown that this modification leads to a multiple increase in the electric charge and a change in the parameters of geometric inhomogeneity of the membrane surface. It has been found that the optimal combination of these characteristics is achieved in the case of a sample containing 3 wt % TiO2, which provides a maximum increase (by a factor of 1.5) in the limiting current density due to electroconvection, which occurs according to the mechanism of electroosmosis of the first kind. The same sample demonstrates the minimum threshold values of the potential drop required for the transition from equilibrium electroconvection to the non-equilibrium one.
      PubDate: 2021-09-01
      DOI: 10.1134/S2517751621050061
       
  • Membrane Technologies for Decarbonization

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      Abstract: The deteriorating environmental situation has stimulated the world community to develop research related to the decarbonization of the economy and hydrogen energy. These two areas are essentially focused on membrane technologies, which play a crucial role in solving key tasks for these areas. This review is devoted to this research. The first part describes various membrane technologies aimed at capturing CO2 from the most common gas mixtures, primarily containing nitrogen, methane, and hydrogen. In recent years, studies related to the amine purification of CO2, including membrane technologies, and the use of porous membranes filled with ionic liquids has also been intensively developed. Electromembrane technologies are also being developed that allow not only capture of CO2 but also to process it into fuel or valuable chemicals. The course taken by several developed countries, including Russia, for the development of hydrogen energy includes the production, purification of hydrogen, and its conversion into energy. It should be noted that membrane technologies are fundamentally important for the development of each of these areas. Thus, the evolution of hydrogen is possible with the use of polymer membranes, and for deep purification and production of high-purity hydrogen by membrane catalysis; membranes based on palladium alloys are used. Finally, fuel cells are developed to produce energy from hydrogen, the most important part of which are proton or oxygen-conducting membranes.
      PubDate: 2021-09-01
      DOI: 10.1134/S2517751621050024
       
  • Influence of Ionic Liquid on Transport Properties of Hybrid Membranes in
           the Lactic Acid Dehydration Process

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      Abstract: Membranes have been developed for the pervaporative dehydration of lactic acid used for the production of biodegradable polymers: polylactides, polylactic acid, and medical plastics. Membranes were obtained by modifying poly-2,6-dimethyl-1,4-phenylene oxide with small amounts (5 wt %) of a new complex filler containing equal amounts of variegated star macromolecules having six polystyrene arms and six arms of the diblock copolymer poly-2-vinylpyridine-block-poly-tert-butylmethacrylate and the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The structure and physical parameters of the membranes were analyzed using thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy, and the density of the membranes was measured by the flotation method. The transport properties of the membranes were investigated in sorption experiments, as well as by pervaporation of a water–lactic acid mixture. It has been shown that the introduction of small amounts of the new modifier into the membrane alters the internal structure of membranes and favorably affects the transport properties of membranes, improving the total permeate flux and increasing the separation efficiency by more than 7 times; the separation factor reaches 2560 in the case of dehydration of lactic acid containing 25 wt % water.
      PubDate: 2021-09-01
       
  • Mathematical Modelling of a Nanoparticle Motion in a Membrane Pore under
           Action of Molecular Forces

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      Abstract: A mathematical model is developed to describe microfiltration on membrane filters with plane-parallel and cylindrical pores. Consideration is given to two cases of motion of Brownian particles having a radius R comparable to the radius of the filter channel a. Relations are presented for the dependence of the efficiency of particle deposition on the channel walls on the parameter \({{æ }} = R{{a}^{{ - 1}}}\) with different values of the molecular interaction constant and with allowance for the hydrodynamic factor. The results of modeling microfiltration on membrane filters with plane-parallel and cylindrical pores are compared. It is shown that there is a qualitative agreement between the main characteristics of the microfiltration process for these two types of membrane channel cross-section. It is established that the efficiency of purification on membrane filters with cylindrical pores is considerably more significant than the efficiency attained with plane-parallel pores.
      PubDate: 2021-07-01
       
 
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