Pub Date : 2023-06-05DOI: 10.1134/S2517751623030046
V. V. Gil, V. D. Ruleva, M. V. Porozhnyy, M. V. Sharafan
Ion-exchange membranes with high specific selectivity to singly charged ions are in demand in various industries. One of the ways to increase the specific selectivity can be the formation on the membrane surface of a thin layer with a charge opposite to the charge of membrane fixed groups. The possibility of forming such a layer due to the specific interaction of calcium ions with the sulfonate groups of the membrane during treatment with a high-intensity electric current in a CaCl2 solution has been investigated. The ability of heterogeneous (MK-40, Ralex CMH) and homogeneous (CMX, CJMC-5) sulfonated cation-exchange membranes to specifically adsorb calcium ions on their surface has been studied. It has been shown that the CMX membrane exhibits this ability to the greatest extent, which is due to a higher density of (-{text{SO}}_{3}^{ - }) groups on its surface compared to other studied membranes. It has been found that formation of a thin positively charged layer on the surface of the CMX membrane increases the membrane permselectivity coefficient ({{P}_{{{{{text{N}}{{{text{a}}}^{{text{ + }}}}} mathord{left/ {vphantom {{{text{N}}{{{text{a}}}^{{text{ + }}}}} {{text{C}}{{{text{a}}}^{{{text{2 + }}}}}}}} right. kern-0em} {{text{C}}{{{text{a}}}^{{{text{2 + }}}}}}}}}}) by 69%. Moreover, the presence of such a layer does not lead to an increase in undesirable water splitting, which occurs when widely used polyelectrolytes with amino groups are applied as modifiers.
对单电荷离子具有高选择性的离子交换膜在各种工业中都有需求。提高比选择性的方法之一是在膜表面形成与膜固定基团电荷相反的薄层。在CaCl2溶液中用高强度电流处理时,由于钙离子与膜的磺酸基的特定相互作用,形成这样一层的可能性已经被研究过。研究了非均相磺化阳离子交换膜(MK-40、Ralex CMH)和均相磺化阳离子交换膜(CMX、CJMC-5)表面对钙离子的特异性吸附能力。研究表明,CMX膜最大程度地表现出这种能力,这是由于与其他研究膜相比,其表面上的(-{text{SO}}_{3}^{ - })基团密度更高。研究发现,在CMX膜表面形成一层薄的正电荷层,使膜的透性选择系数({{P}_{{{{{text{N}}{{{text{a}}}^{{text{ + }}}}} mathord{left/ {vphantom {{{text{N}}{{{text{a}}}^{{text{ + }}}}} {{text{C}}{{{text{a}}}^{{{text{2 + }}}}}}}} right. kern-0em} {{text{C}}{{{text{a}}}^{{{text{2 + }}}}}}}}}})提高了69%. Moreover, the presence of such a layer does not lead to an increase in undesirable water splitting, which occurs when widely used polyelectrolytes with amino groups are applied as modifiers.
{"title":"Study of the Specific Adsorption of Calcium Ions on the Surface of Heterogeneous and Homogeneous Cation-Exchange Membranes to Increase Their Selectivity to Singly Charged Ions","authors":"V. V. Gil, V. D. Ruleva, M. V. Porozhnyy, M. V. Sharafan","doi":"10.1134/S2517751623030046","DOIUrl":"10.1134/S2517751623030046","url":null,"abstract":"<p>Ion-exchange membranes with high specific selectivity to singly charged ions are in demand in various industries. One of the ways to increase the specific selectivity can be the formation on the membrane surface of a thin layer with a charge opposite to the charge of membrane fixed groups. The possibility of forming such a layer due to the specific interaction of calcium ions with the sulfonate groups of the membrane during treatment with a high-intensity electric current in a CaCl<sub>2</sub> solution has been investigated. The ability of heterogeneous (MK-40, Ralex CMH) and homogeneous (CMX, CJMC-5) sulfonated cation-exchange membranes to specifically adsorb calcium ions on their surface has been studied. It has been shown that the CMX membrane exhibits this ability to the greatest extent, which is due to a higher density of <span>(-{text{SO}}_{3}^{ - })</span> groups on its surface compared to other studied membranes. It has been found that formation of a thin positively charged layer on the surface of the CMX membrane increases the membrane permselectivity coefficient <span>({{P}_{{{{{text{N}}{{{text{a}}}^{{text{ + }}}}} mathord{left/ {vphantom {{{text{N}}{{{text{a}}}^{{text{ + }}}}} {{text{C}}{{{text{a}}}^{{{text{2 + }}}}}}}} right. kern-0em} {{text{C}}{{{text{a}}}^{{{text{2 + }}}}}}}}}})</span> by 69%. Moreover, the presence of such a layer does not lead to an increase in undesirable water splitting, which occurs when widely used polyelectrolytes with amino groups are applied as modifiers.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4550710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-05DOI: 10.1134/S2517751623030034
M. A. Brovkina, N. A. Kutenko, N. V. Loza
A series of composite ion-exchange membranes based on an heterogeneous cation-exchange MK‑40 membrane and polyaniline is obtained under the conditions of electrodiffusion of a monomer and an oxidizing agent. The process of polyaniline synthesis on the membrane surface is accompanied by recording of chronopotentiograms and pH of the solution leaving the desalination compartment. The initial cation-exchange MK-40 membrane and obtained composites based on it are studied by voltammetry and chronopotentiometry in solutions of NaCl, CaCl2, and MgCl2 in the same flow-type electrodialysis cell, in which the composites are obtained. To calculate the transport numbers of counterions in the membranes in solutions of CaCl2 and MgCl2 by chronopotentiometry, the apparent fraction of the conductive membrane surface in a solution of NaCl is calculated based on the experimental data on the potentiometric transport numbers of counterions in the membrane. The conditions for the synthesis of polyaniline on the surface of an heterogeneous MK-40 membrane which result in the preparation of samples with selectivity to singly charged ions are found out.
{"title":"Electrochemical Behavior of Polyaniline-Modified Cation-Exchange Heterogeneous Membranes in Solutions Containing Mono- and Bivalent Cations","authors":"M. A. Brovkina, N. A. Kutenko, N. V. Loza","doi":"10.1134/S2517751623030034","DOIUrl":"10.1134/S2517751623030034","url":null,"abstract":"<p>A series of composite ion-exchange membranes based on an heterogeneous cation-exchange MK‑40 membrane and polyaniline is obtained under the conditions of electrodiffusion of a monomer and an oxidizing agent. The process of polyaniline synthesis on the membrane surface is accompanied by recording of chronopotentiograms and pH of the solution leaving the desalination compartment. The initial cation-exchange MK-40 membrane and obtained composites based on it are studied by voltammetry and chronopotentiometry in solutions of NaCl, CaCl<sub>2</sub>, and MgCl<sub>2</sub> in the same flow-type electrodialysis cell, in which the composites are obtained. To calculate the transport numbers of counterions in the membranes in solutions of CaCl<sub>2</sub> and MgCl<sub>2</sub> by chronopotentiometry, the apparent fraction of the conductive membrane surface in a solution of NaCl is calculated based on the experimental data on the potentiometric transport numbers of counterions in the membrane. The conditions for the synthesis of polyaniline on the surface of an heterogeneous MK-40 membrane which result in the preparation of samples with selectivity to singly charged ions are found out.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4550717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-05DOI: 10.1134/S2517751623030058
N. V. Loza, N. A. Kutenko, N. A. Kononenko, Yu. M. Volfkovich, V. E. Sosenkin
Comprehensive characterization of basic MK-40 and Ralex CMH heterogeneous cation-exchange membranes and composite membranes with polyaniline based on them is performed including the determination of specific electrical conductivity and diffusion permeability; measurement of current–voltage curves in solutions of sodium, calcium, and magnesium chlorides and hydrochloric acid and curves of distribution of water with respect to the bond energies and effective pore radii as well as assessment of the transport structural parameters of a microheterogeneous model. The time of synthesis of polyaniline on the surface of cation-exchange membranes for obtaining samples with an anisotropic structure and asymmetric electric transport properties is determined by successive diffusion of a solution of an oxidizing agent and a monomer through the membrane into water. It is shown based on the analysis of the electric transport properties, structural characteristics, and model transport structural parameters of the membranes in solutions of singly and doubly charged ions that the obtained materials are promising for use in the processes of electrodialysis desalination of multicomponent solutions.
{"title":"Transport Properties and Structure of Anisotropic Composites Based on Cation-Exchange Membranes and Polyaniline","authors":"N. V. Loza, N. A. Kutenko, N. A. Kononenko, Yu. M. Volfkovich, V. E. Sosenkin","doi":"10.1134/S2517751623030058","DOIUrl":"10.1134/S2517751623030058","url":null,"abstract":"<p>Comprehensive characterization of basic MK-40 and Ralex CMH heterogeneous cation-exchange membranes and composite membranes with polyaniline based on them is performed including the determination of specific electrical conductivity and diffusion permeability; measurement of current–voltage curves in solutions of sodium, calcium, and magnesium chlorides and hydrochloric acid and curves of distribution of water with respect to the bond energies and effective pore radii as well as assessment of the transport structural parameters of a microheterogeneous model. The time of synthesis of polyaniline on the surface of cation-exchange membranes for obtaining samples with an anisotropic structure and asymmetric electric transport properties is determined by successive diffusion of a solution of an oxidizing agent and a monomer through the membrane into water. It is shown based on the analysis of the electric transport properties, structural characteristics, and model transport structural parameters of the membranes in solutions of singly and doubly charged ions that the obtained materials are promising for use in the processes of electrodialysis desalination of multicomponent solutions.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4218882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-05DOI: 10.1134/S2517751623030071
V. P. Makrushin, V. K. Chernikov, I. S. Levin, A. A. Kossov, S. M. Matson
The thermo-oxidative stability and gas transport properties of poly(4-methyl-2-pentyne) (PMP) samples of the mixed configurational composition (50% cis-units) in the presence of phenolic antioxidants Irganox 1076, Irganox 1010, Vulkanox BHT, and Rianox 1520 differing in the nature and structure of substituents on the benzene ring is studied. The annealing of PMP films at 140°С demonstrates that the films with the added Irganox 1076 and Irganox 1010 maintain the strength and stability of gas transport properties for at least 150 h of total heating after moderate decrease in permeability (∼30%) for the first 48 h of heating. PMP films with Vulkanox BHT and Rianox 1520 upon 48 h of heating at 140°С show an increase in gas permeability coefficients, indicating the onset of polymer degradation, and after 100 h of heating they are destroyed. The wide-angle X-ray diffraction of the films with the most effective stabilizers Irganox 1076 and Irganox 1010 reveals a decrease in interchain distances upon annealing which provides evidence for an increase in the packing density of macromolecules as a result of thermally activated relaxation.
{"title":"Effect of Introduction of Phenolic Antioxidants on the Thermo-Oxidative Stability and Gas Permeability of Poly(4-methyl-2-pentyne)","authors":"V. P. Makrushin, V. K. Chernikov, I. S. Levin, A. A. Kossov, S. M. Matson","doi":"10.1134/S2517751623030071","DOIUrl":"10.1134/S2517751623030071","url":null,"abstract":"<p>The thermo-oxidative stability and gas transport properties of poly(4-methyl-2-pentyne) (PMP) samples of the mixed configurational composition (50% <i>cis</i>-units) in the presence of phenolic antioxidants Irganox 1076, Irganox 1010, Vulkanox BHT, and Rianox 1520 differing in the nature and structure of substituents on the benzene ring is studied. The annealing of PMP films at 140°С demonstrates that the films with the added Irganox 1076 and Irganox 1010 maintain the strength and stability of gas transport properties for at least 150 h of total heating after moderate decrease in permeability (∼30%) for the first 48 h of heating. PMP films with Vulkanox BHT and Rianox 1520 upon 48 h of heating at 140°С show an increase in gas permeability coefficients, indicating the onset of polymer degradation, and after 100 h of heating they are destroyed. The wide-angle X-ray diffraction of the films with the most effective stabilizers Irganox 1076 and Irganox 1010 reveals a decrease in interchain distances upon annealing which provides evidence for an increase in the packing density of macromolecules as a result of thermally activated relaxation.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4218158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-05DOI: 10.1134/S2517751623030095
Yu. A. Zakharova, V. G. Sergeyev
Significant increase of ion selectivity has been observed for Nafion membranes modified by poly(diallyldimethylammonium chloride) (PDADMAC) in the presence of lower aliphatic alcohols and NaCl. It has been found that addition of the salt into the alcohol-containing modification solutions results not only in decrease of diffusional permeability towards vanadyl ions P but also in simultaneous two- to threefold growth of proton conductivity σ in comparison with the membranes modified in the alcohol-water solutions in the absence of the salt. As a result, ion selectivity of the membranes calculated as σ/P ratio has been increased in ∼4 orders of magnitude as compared with pristine Nafion 112 membrane. Conceivable mechanism of the ion selectivity increasing is proposed for the membranes modified by PDADMAC in the presence of lower aliphatic alcohols and NaCl.
{"title":"Modification of Nafion Membranes by Polycation in the Presence of Lower Alyphatic Alcohols and Salt","authors":"Yu. A. Zakharova, V. G. Sergeyev","doi":"10.1134/S2517751623030095","DOIUrl":"10.1134/S2517751623030095","url":null,"abstract":"<p>Significant increase of ion selectivity has been observed for Nafion membranes modified by poly(diallyldimethylammonium chloride) (PDADMAC) in the presence of lower aliphatic alcohols and NaCl. It has been found that addition of the salt into the alcohol-containing modification solutions results not only in decrease of diffusional permeability towards vanadyl ions <i>P</i> but also in simultaneous two- to threefold growth of proton conductivity σ in comparison with the membranes modified in the alcohol-water solutions in the absence of the salt. As a result, ion selectivity of the membranes calculated as σ/<i>P</i> ratio has been increased in ∼4 orders of magnitude as compared with pristine Nafion 112 membrane. Conceivable mechanism of the ion selectivity increasing is proposed for the membranes modified by PDADMAC in the presence of lower aliphatic alcohols and NaCl.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4218251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.1134/S2517751623020051
V. G. Polevaya, A. A. Kossov, S. M. Matson
In this work, poly(4-methyl-2-pentyne) (PMP) with quaternary ammonium salts has been functionalized in order to increase CO2 selectivity. Functional groups have been introduced by a two-stage method: (i) bromination of the initial polymer and (ii) addition of tertiary alkylamines, namely trimethylamine (TMA) and trimethylamine (TEA). It has been established that the optimal amount of introduced functional groups, while maintaining the mechanical properties of the polymer, is up to 5 mol %. The results of organoelemental analysis and IR spectroscopy confirm the PMP functionalization. X-ray diffraction patterns of the samples indicate an increase in the interchain distance in the series initial PMP–brominated PMP–functionalized PMP. TGA data confirm high thermal and thermal-oxidative stability. The coefficients of permeability, solubility, and diffusion of PMP samples containing TMA and TEA salts have been determined for individual gases. An increased ideal selectivity for the separation of gas pairs CO2/N2 by 2–3 times and CO2/CH4 by 1.5–2 times has been achieved while maintaining the permeability at a high level.
{"title":"Synthesis and Properties of Poly(4-Methyl-2-Pentyne) Containing Quaternary Ammonium Salts with Methyl and Ethyl Substituents","authors":"V. G. Polevaya, A. A. Kossov, S. M. Matson","doi":"10.1134/S2517751623020051","DOIUrl":"10.1134/S2517751623020051","url":null,"abstract":"<p>In this work, poly(4-methyl-2-pentyne) (PMP) with quaternary ammonium salts has been functionalized in order to increase CO<sub>2</sub> selectivity. Functional groups have been introduced by a two-stage method: (i) bromination of the initial polymer and (ii) addition of tertiary alkylamines, namely trimethylamine (TMA) and trimethylamine (TEA). It has been established that the optimal amount of introduced functional groups, while maintaining the mechanical properties of the polymer, is up to 5 mol %. The results of organoelemental analysis and IR spectroscopy confirm the PMP functionalization. X-ray diffraction patterns of the samples indicate an increase in the interchain distance in the series initial PMP–brominated PMP–functionalized PMP. TGA data confirm high thermal and thermal-oxidative stability. The coefficients of permeability, solubility, and diffusion of PMP samples containing TMA and TEA salts have been determined for individual gases. An increased ideal selectivity for the separation of gas pairs CO<sub>2</sub>/N<sub>2</sub> by 2–3 times and CO<sub>2</sub>/CH<sub>4</sub> by 1.5–2 times has been achieved while maintaining the permeability at a high level.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S2517751623020051.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5037050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.1134/S2517751623020075
D. L. Zagorskiy, I. M. Doludenko, D. R. Khairetdinova
The paper considers the specific features of obtaining metal nanowires by matrix synthesis based on track membranes. The first part of the work considers the main ideas of the method and reviews the published sources devoted to producing nanowires of various types—single-component (from one metal) and multicomponent (from two or several metals). Variants of obtaining homogeneous structures (so-called alloyed nanowires) and heterogeneous structures (so-called layered nanowires) are considered for the latter case. A series of specific features of the electrodeposition method in the case of carrying out the process in a limited volume of membrane pores is considered. The second part of the work considers the experimental results obtained by the authors upon studying the electrodeposition of nanowires made of an iron–nickel alloy. The aim is to find a relationship between the conditions of the synthesis of nanowires and their structure and elemental composition. The features of the electrodeposition of nanowires are investigated and their topography is studied by electron microscopy (with elemental analysis); X-ray method is applied for studying the structure. So-called abnormal electrodeposition of iron is detected. The dependence of the integral elemental composition of the obtained nanowires on the pore diameter and growth voltage is discussed. Data on the nature of distribution of elements along the length of the nanowires are obtained; it is shown that the nonuniformity of the composition is determined by the conditions of production (in particular, different diffusion mobilities of ions in narrow pore channels) as well as depends on the voltage and diameter of the pore channels. Based on the X-ray diffraction data, the type of the lattice (FCC) is determined, and the nature of the change in the lattice parameter is shown which is presumably associated with the difference in the ionic radii of metals.
{"title":"Features of the Process of Galvanic Deposition of Metals into the Pores of Ion Track Membranes","authors":"D. L. Zagorskiy, I. M. Doludenko, D. R. Khairetdinova","doi":"10.1134/S2517751623020075","DOIUrl":"10.1134/S2517751623020075","url":null,"abstract":"<p>The paper considers the specific features of obtaining metal nanowires by matrix synthesis based on track membranes. The first part of the work considers the main ideas of the method and reviews the published sources devoted to producing nanowires of various types—single-component (from one metal) and multicomponent (from two or several metals). Variants of obtaining homogeneous structures (so-called alloyed nanowires) and heterogeneous structures (so-called layered nanowires) are considered for the latter case. A series of specific features of the electrodeposition method in the case of carrying out the process in a limited volume of membrane pores is considered. The second part of the work considers the experimental results obtained by the authors upon studying the electrodeposition of nanowires made of an iron–nickel alloy. The aim is to find a relationship between the conditions of the synthesis of nanowires and their structure and elemental composition. The features of the electrodeposition of nanowires are investigated and their topography is studied by electron microscopy (with elemental analysis); X-ray method is applied for studying the structure. So-called abnormal electrodeposition of iron is detected. The dependence of the integral elemental composition of the obtained nanowires on the pore diameter and growth voltage is discussed. Data on the nature of distribution of elements along the length of the nanowires are obtained; it is shown that the nonuniformity of the composition is determined by the conditions of production (in particular, different diffusion mobilities of ions in narrow pore channels) as well as depends on the voltage and diameter of the pore channels. Based on the X-ray diffraction data, the type of the lattice (FCC) is determined, and the nature of the change in the lattice parameter is shown which is presumably associated with the difference in the ionic radii of metals.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4739972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.1134/S2517751623020038
L. P. Didenko, V. N. Babak, L. A. Sementsova, T. V. Dorofeeva, P. E. Chizhov, S. V. Gorbunov
The regularities of steam conversion of ethane and methane–ethane mixtures containing 5, 10, and 15% ethane in a reactor with a membrane in the form of a Pd–6% Ru foil with a thickness of 30 μm and a NIAP-03-01 nickel catalyst are investigated. The reaction is studied under the following conditions: 773 and 823 K, feed space velocities of 1800 and 3600 h−1, and steam/feed ratios of 3 and 5. Steam conversion of ethane was studied in a temperature range of 773–853 K. Comparative experiments in a conventional reactor show that, in the membrane reactor, the conversion of the feedstock by the reaction of steam conversion with the formation of H2 and CO2 increases and its hydrocracking decreases. Evacuation of the permeate leads to an increase in the yield of H2 and CO2. When decreasing the steam/feed ratio from 5 down to 3, hydrocracking of the feedstock and rate of formation of carbon deposits increase. The optimum conditions for steam conversion of ethane and methane–ethane mixtures are T = 773–853 and 773 K, respectively, 1800 h–1 and steam/feed ratio of 5. The found regularities are similar to those earlier obtained for other types of feedstock (propane–methane mixtures, propane, n-butane, a mixture simulating the average composition of associated petroleum gas) in this membrane reactor.
{"title":"Steam Conversion of Ethane and Methane–Ethane Mixtures in a Membrane Reactor with a Foil Made of a Pd–Ru Alloy","authors":"L. P. Didenko, V. N. Babak, L. A. Sementsova, T. V. Dorofeeva, P. E. Chizhov, S. V. Gorbunov","doi":"10.1134/S2517751623020038","DOIUrl":"10.1134/S2517751623020038","url":null,"abstract":"<p>The regularities of steam conversion of ethane and methane–ethane mixtures containing 5, 10, and 15% ethane in a reactor with a membrane in the form of a Pd–6% Ru foil with a thickness of 30 μm and a NIAP-03-01 nickel catalyst are investigated. The reaction is studied under the following conditions: 773 and 823 K, feed space velocities of 1800 and 3600 h<sup>−1</sup>, and steam/feed ratios of 3 and 5. Steam conversion of ethane was studied in a temperature range of 773–853 K. Comparative experiments in a conventional reactor show that, in the membrane reactor, the conversion of the feedstock by the reaction of steam conversion with the formation of H<sub>2</sub> and CO<sub>2</sub> increases and its hydrocracking decreases. Evacuation of the permeate leads to an increase in the yield of H<sub>2</sub> and CO<sub>2</sub>. When decreasing the steam/feed ratio from 5 down to 3, hydrocracking of the feedstock and rate of formation of carbon deposits increase. The optimum conditions for steam conversion of ethane and methane–ethane mixtures are <i>T</i> = 773–853 and 773 K, respectively, 1800 h<sup>–1</sup> and steam/feed ratio of 5. The found regularities are similar to those earlier obtained for other types of feedstock (propane–methane mixtures, propane, <i>n</i>-butane, a mixture simulating the average composition of associated petroleum gas) in this membrane reactor.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4739979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.1134/S2517751623020087
V. V. Zhmakin, S. Yu. Markova, V. V. Teplyakov, M. G. Shalygin
This work is devoted to the evaluation of xenon permeability coefficients for a wide range of polymeric membrane materials, as well as the primary experimental verification of the calculation results for materials used in the production of gas separation membranes. The solution of the problem of O2/Xe mixture separation as a base for xenon-containing waste medical gas mixtures where it is possible to recover xenon for its reuse has been emphasized. The xenon permeability coefficients have been evaluated using a correlation approach that relates the molecular properties of a gas to gas permeability, and available literature data on the permeability of other gases. The results obtained make it possible to distinguish two main groups of membrane polymers in the Robeson diagram for O2/Xe gas pair: xenon-selective (polysiloxane-based rubbers and highly permeable functional polyacetylenes) and oxygen-selective (polyimides, PIMs, perfluorinated polymers). Industrial composite membrane MDK with a selective layer of silicone copolymer and laboratory composite membranes based on PSf and PVTMS have been experimentally investigated. The obtained data demonstrate satisfactory convergence of the experimental values with the estimated ones. Based on the results obtained, MDK membrane can be recommended as xenon-selective for xenon recovery (α(Xe/O2) = 3.1).
{"title":"Potential of Polymer Membranes for Xenon Recovery from Medical Waste Gas Mixtures","authors":"V. V. Zhmakin, S. Yu. Markova, V. V. Teplyakov, M. G. Shalygin","doi":"10.1134/S2517751623020087","DOIUrl":"10.1134/S2517751623020087","url":null,"abstract":"<p>This work is devoted to the evaluation of xenon permeability coefficients for a wide range of polymeric membrane materials, as well as the primary experimental verification of the calculation results for materials used in the production of gas separation membranes. The solution of the problem of O<sub>2</sub>/Xe mixture separation as a base for xenon-containing waste medical gas mixtures where it is possible to recover xenon for its reuse has been emphasized. The xenon permeability coefficients have been evaluated using a correlation approach that relates the molecular properties of a gas to gas permeability, and available literature data on the permeability of other gases. The results obtained make it possible to distinguish two main groups of membrane polymers in the Robeson diagram for O<sub>2</sub>/Xe gas pair: xenon-selective (polysiloxane-based rubbers and highly permeable functional polyacetylenes) and oxygen-selective (polyimides, PIMs, perfluorinated polymers). Industrial composite membrane MDK with a selective layer of silicone copolymer and laboratory composite membranes based on PSf and PVTMS have been experimentally investigated. The obtained data demonstrate satisfactory convergence of the experimental values with the estimated ones. Based on the results obtained, MDK membrane can be recommended as xenon-selective for xenon recovery (α(Xe/O<sub>2</sub>) = 3.1).</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4739670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.1134/S251775162302004X
O. V. Lebedeva, T. V. Raskulova, S. A. Beznosyuk, A. V. Ryabykh, L. V. Fomina, E. I. Sipkina
Hybrid organic-inorganic membranes based on tetraethoxysilane and orthophosphoric acid-doped copolymers of 4-vinylpyridine (4-VP) and 2-hydroxyethyl methacrylate (HEMA) have been formed by the sol-gel synthesis method. The membranes are characterized by high values of exchange capacity and proton conductivity. An increase in the proton conductivity of hybrid organo-inorganic membranes compared to the initial copolymer can be associated with the generation of crystallization water during the formation of a silicon dioxide fragment, which follows from quantum-chemical modeling of the local structure of the membrane. The latter includes an organic part from the copolymerization product of 4-VP with HEMA (44 atoms) and an inorganic part of 27 atoms, repeating the structure of the silicon dioxide block.
{"title":"Structural Features of 4-VP-HEMA-SiO2 Hybrid Membranes and Their Proton Conductivity","authors":"O. V. Lebedeva, T. V. Raskulova, S. A. Beznosyuk, A. V. Ryabykh, L. V. Fomina, E. I. Sipkina","doi":"10.1134/S251775162302004X","DOIUrl":"10.1134/S251775162302004X","url":null,"abstract":"<p>Hybrid organic-inorganic membranes based on tetraethoxysilane and orthophosphoric acid-doped copolymers of 4-vinylpyridine (4-VP) and 2-hydroxyethyl methacrylate (HEMA) have been formed by the sol-gel synthesis method. The membranes are characterized by high values of exchange capacity and proton conductivity. An increase in the proton conductivity of hybrid organo-inorganic membranes compared to the initial copolymer can be associated with the generation of crystallization water during the formation of a silicon dioxide fragment, which follows from quantum-chemical modeling of the local structure of the membrane. The latter includes an organic part from the copolymerization product of 4-VP with HEMA (44 atoms) and an inorganic part of 27 atoms, repeating the structure of the silicon dioxide block.</p>","PeriodicalId":700,"journal":{"name":"Membranes and Membrane Technologies","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4739969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}