Editorial

4 pages, 191 KiB

Open AccessEditorial

by Natalia Pismenskaya and Victor Nikonenko

Membranes 2021, 11(11), 814; https://doi.org/10.3390/membranes11110814 - 26 Oct 2021

Cited by 2 | Viewed by 1713

Synthetic ion exchange membranes (IEMs) are made from organic, inorganic, or mixed and composite materials [...] Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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12 pages, 4348 KiB

Open AccessArticle

Purification of Methylsulfonylmethane from Mixtures Containing Salt by Conventional Electrodialysis

by Xinlai Wei, Yaoming Wang, Haiyang Yan, Ke Wu and Tongwen Xu

Membranes 2020, 10(2), 23; https://doi.org/10.3390/membranes10020023 - 01 Feb 2020

Cited by 9 | Viewed by 4246

Abstract

Methylsulfonylmethane (MSM) is one of the main sources of sulfur for living bodies, but it is hard to obtain as a pure compound. Conventional electrodialysis (CED) is a mature technology that can be used for the separation and purification of biochemical products. In [...] Read more.

Methylsulfonylmethane (MSM) is one of the main sources of sulfur for living bodies, but it is hard to obtain as a pure compound. Conventional electrodialysis (CED) is a mature technology that can be used for the separation and purification of biochemical products. In this study, the purification of MSM from mixtures containing salt was performed by CED. The effects of operating conditions such as operation voltage drop, feed MSM concentration, and electrolyte salt concentration on the separation performances were investigated. The results showed that the current efficiency reached 74.0%, and the energy consumption could be 12.3 Wh·L⁻¹. As for the recovery rate and desalination rate, the highest recovery rate could be 97.4%, and the desalination rate was 98.5%. Based on process energy consumption calculation, the total cost of the whole process was estimated at only 2.34 $·t⁻¹. Thus, CED is highly efficient and cost-effective for the separation and purification of MSM. Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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20 pages, 9228 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Systematic Study of the Impact of Pulsed Electric Field Parameters (Pulse/Pause Duration and Frequency) on ED Performances during Acid Whey Treatment

by Guillaume Dufton, Sergey Mikhaylin, Sami Gaaloul and Laurent Bazinet

Membranes 2020, 10(1), 14; https://doi.org/10.3390/membranes10010014 - 11 Jan 2020

Cited by 20 | Viewed by 3122

Abstract

Processing acid whey is still a challenge for the dairy industry due to its high lactic acid and mineral contents. Their removal processes represent a high investment and running cost in addition to significant production of polluting effluents. A previous study showed that [...] Read more.

Processing acid whey is still a challenge for the dairy industry due to its high lactic acid and mineral contents. Their removal processes represent a high investment and running cost in addition to significant production of polluting effluents. A previous study showed that the use of electrodialysis with the application of pulsed electric fields (PEFs) was sufficiently efficient to produce dryable acid whey with reduced scaling issues during the process. In the present work, eight PEF conditions using different pulse/pause durations and frequencies were tested for 1) process optimization and 2) understanding of the underlying mechanisms involved in PEF process improvements. Best results were obtained for PEF conditions (5 s/5 s) and (15 s/15 s) with almost complete scaling mitigation and minimal energy consumption (5.3 ± 0.4 Wh/g of lactic acid vs. 9.33 ± 1.38 Wh/g for continuous current). Longer pause times also led to better divalent ion demineralization at the expense of sodium elimination induced by stronger affinity with the membrane and longer retention times. For the first time, PEF parameters of relatively low frequencies (<1) were studied in sub-limiting current conditions on a complex solution such as acid whey. Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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15 pages, 1941 KiB

Open AccessArticle

Neutralization Dialysis for Phenylalanine and Mineral Salt Separation. Simple Theory and Experiment

by Anton Kozmai, Elena Goleva, Vera Vasil’eva, Victor Nikonenko and Natalia Pismenskaya

Membranes 2019, 9(12), 171; https://doi.org/10.3390/membranes9120171 - 10 Dec 2019

Cited by 13 | Viewed by 2822

Abstract

A simple non-steady state mathematical model is proposed for the process of purification of an amino acid solution from mineral salts by the method of neutralization dialysis (ND), carried out in a circulating hydrodynamic mode. The model takes into account the characteristics of [...] Read more.

A simple non-steady state mathematical model is proposed for the process of purification of an amino acid solution from mineral salts by the method of neutralization dialysis (ND), carried out in a circulating hydrodynamic mode. The model takes into account the characteristics of membranes (thickness, exchange capacity and electric conductivity) and solution (concentration and components nature) as well as the solution flow rate in dialyzer compartments. In contrast to the known models, the new model considers a local change in the ion concentration in membranes and the adjacent diffusion layers. In addition, the model takes into consideration the ability of the amino acid to enter the protonation/deprotonation reactions. A comparison of the results of simulations with experimental data allows us to conclude that the model adequately describes the ND of a strong electrolyte (NaCl) and amino acid (phenylalanine) mixture solutions in the case where the diffusion ability of amino acids in membranes is much less, than mineral salts. An example shows the application of the model to predict the fluxes of salt ions through ion exchange membranes as well as pH of the desalination solution at a higher than in experiments flow rate of solutions in ND dialyzer compartments. Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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20 pages, 2462 KiB

Open AccessFeature PaperArticle

Concentration Dependencies of Diffusion Permeability of Anion-Exchange Membranes in Sodium Hydrogen Carbonate, Monosodium Phosphate, and Potassium Hydrogen Tartrate Solutions

by Natalia Pismenskaya, Veronika Sarapulova, Ekaterina Nevakshenova, Natalia Kononenko, Maria Fomenko and Victor Nikonenko

Membranes 2019, 9(12), 170; https://doi.org/10.3390/membranes9120170 - 10 Dec 2019

Cited by 15 | Viewed by 3340

Abstract

The concentration dependencies of diffusion permeability of homogeneous (AMX-Sb and AX) and heterogeneous (MA-41 and FTAM-EDI) anion-exchange membranes (AEMs) is obtained in solutions of ampholytes (sodium bicarbonate, NaHCO₃; monosodium phosphate, NaH₂PO₄; and potassium hydrogen tartrate, KHT) and [...] Read more.

The concentration dependencies of diffusion permeability of homogeneous (AMX-Sb and AX) and heterogeneous (MA-41 and FTAM-EDI) anion-exchange membranes (AEMs) is obtained in solutions of ampholytes (sodium bicarbonate, NaHCO₃; monosodium phosphate, NaH₂PO₄; and potassium hydrogen tartrate, KHT) and a strong electrolyte (sodium chloride, NaCl). It is established that the diffusion permeability of AEMs increases with dilution of the ampholyte solutions, while it decreases in the case of the strong electrolyte solution. The factors causing the unusual form of concentration dependencies of AEMs in the ampholyte solutions are considered: (1) the enrichment of the internal AEM solution with multiply charged counterions and (2) the increase in the pore size of AEMs with dilution of the external solution. The enrichment of the internal solution of AEMs with multiply charged counterions is caused by the Donnan exclusion of protons, which are the products of protolysis reactions. The increase in the pore size is conditioned by the stretching of the elastic polymer matrix due to the penetration of strongly hydrated anions of carbonic, phosphoric, and tartaric acids into the AEMs. Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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13 pages, 6093 KiB

Open AccessArticle

A Study of Ralex Membrane Morphology by SEM

by Elmara M. Akberova, Vera I. Vasil’eva, Victor I. Zabolotsky and Lubos Novak

Membranes 2019, 9(12), 169; https://doi.org/10.3390/membranes9120169 - 06 Dec 2019

Cited by 16 | Viewed by 4062

Abstract

A comparative analysis of the effect of the manufacturing technology of heterogeneousion-exchange membranes Ralex CM Pes manufactured by MEGA a.s. (Czech Republic) on the structural properties of their surface and cross section by SEM was carried out. The CM Pes membrane is a [...] Read more.

A comparative analysis of the effect of the manufacturing technology of heterogeneousion-exchange membranes Ralex CM Pes manufactured by MEGA a.s. (Czech Republic) on the structural properties of their surface and cross section by SEM was carried out. The CM Pes membrane is a composite of a sulfonated ion-exchanger with inert binder of polyethylene and reinforcing polyester fiber. In the manufacture of membranes Ralex the influence of two factors was investigated. First, the time of ion-exchange grain millingvaried at a constant resin/polyethylene ratio. Second, the ratio of the cation-exchanger and the inert binder of polyethylene varied. It has been found that the membrane surface becomes more electrically homogeneous with the growth of the ion-exchanger loading and a decrease in its particle size. With an increase in the milling time of resin grainsfrom 5 to 80 min a more than 1.5-fold decrease in their radius and in the distance between them was revealed.Besides, there is a 1.5-fold decrease in the fraction, as well as in the size of pores and structure defects. The fraction of the ion-exchange phase on the membrane surface decreases by 7%. With an increase in the resin loading from 45 to 70 wt %, the growth of the fraction of conducting regions on the surface is almost twofold, while their sizes remain practically unchanged. More significant changes in the surface structure of the studied membranes are established in comparison with the cross section. An increase in the resin content in the membranes from 45 to 70 wt % corresponds to a 43% increment of its fraction on the cross-section.The increase in the ion-exchanger content of Ralex membranes is accompanied by the growth of the fraction of macropores and structure defects on the membrane surface by 70% and a twofold decrease in the distance between conducting zones. Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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18 pages, 1134 KiB

Open AccessArticle

How Molecular Weight Cut-Offs and Physicochemical Properties of Polyether Sulfone Membranes Affect Peptide Migration and Selectivity during Electrodialysis with Filtration Membranes

by Sabita Kadel, Geneviève Pellerin, Jacinthe Thibodeau, Véronique Perreault, Carole Lainé and Laurent Bazinet

Membranes 2019, 9(11), 153; https://doi.org/10.3390/membranes9110153 - 13 Nov 2019

Cited by 30 | Viewed by 7261

Abstract

Filtration membranes (FMs) are an integral part of electrodialysis with filtration membranes (EDFM), a green and promising technology for bioactive peptide fractionation. Therefore, it is paramount to understand how physicochemical properties of FMs impact global and selective peptide migration to anionic (A⁻ [...] Read more.

Filtration membranes (FMs) are an integral part of electrodialysis with filtration membranes (EDFM), a green and promising technology for bioactive peptide fractionation. Therefore, it is paramount to understand how physicochemical properties of FMs impact global and selective peptide migration to anionic (A⁻_RC) and cationic (C⁺_RC) peptide recovery compartments during their simultaneous separation by EDFM. In this context, six polyether sulfone (PES) membranes with molecular weight cut-offs (MWCO) of 5, 10, 20, 50, 100 and 300 kDa were characterized and used during EDFM to separate peptides from a complex whey protein hydrolysate. Surface charge, roughness, thickness and surface/pores nature of studied PES membranes were similar with small differences in conductivity, porosity and pore size distribution. Interestingly, global peptides migration to both recovery compartments increased linearly as a function of MWCO. However, peptide selectivity changed according to the recovery compartments and/or the peptide’s charge and MW with an increase in MWCO of FMs. Indeed, in A⁻_RC, the relative abundance (RA) of peptides having low negative charge and MW (IDALNENK and VLVLDTDYK) decreased (45% to 19%) with an increase in MWCO, while the opposite for peptides having high negative charge and MW (TPEVDDEALEK, TPEVDDEALEKFDK & VYVEELKPTPEGDLEILLQK) (increased from 16% to 43%). Concurrently, in C⁺_RC, regardless of MWCO used, the highest RA was observed for peptides having low positive charge and MW (IPAVFK & ALPMHIR). It was the first time that the significant impact of charge, MWCO and pore size distribution of PES membranes on a wide range of MWCO was demonstrated on EDFM performances. Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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14 pages, 1925 KiB

Open AccessArticle

Effect of Carbon Dioxide Loading on Removal of Heat Stable Salts from Amine Solvent by Electrodialysis

by Evgeniia Grushevenko, Stepan Bazhenov, Vladimir Vasilevsky, Eduard Novitsky, Maxim Shalygin and Alexey Volkov

Membranes 2019, 9(11), 152; https://doi.org/10.3390/membranes9110152 - 13 Nov 2019

Cited by 14 | Viewed by 3424

Abstract

Heat stable salts (HSS) formed and continuously accumulated in the amine-based solvents due to solvent degradation and impurities in the feed gas can dramatically change the efficiency of the amine scrubbing process. HSS can be removed by using different methods including membrane separation [...] Read more.

Heat stable salts (HSS) formed and continuously accumulated in the amine-based solvents due to solvent degradation and impurities in the feed gas can dramatically change the efficiency of the amine scrubbing process. HSS can be removed by using different methods including membrane separation such as electrodialysis (ED). In this work, we studied the effect of CO₂ loading of the lean 30 wt % monoethanolamine (MEA) solution on the efficiency of HSS removal and MEA loss. In the model MEA solution containing HSS on the level of 48 meq/L, the carbon dioxide concentration was varied from 0.2 down to 0 mole (CO₂)/mole (MEA). The reclaiming of model MEA solution was carried out by lab-scale two-stage ED unit when the concentrate stream after the first stage was additionally treated using ED (second stage) that allowed reducing MEA loss. It was shown that the decrease of carbon dioxide content from 0.2 down to 0 mole (CO₂)/mole (MEA) resulted in a substantial reduction of both parameters—the MEA loss and the specific power consumption with respect to extracted HSS (from 140 down 37 kJ per 1 g of recovered HSS anions). This can be explained by the drop in the total concentration of ions formed by the interaction of MEA solution with carbon dioxide. However, the change of CO₂ loading is associated with additional power consumption towards further solvent regeneration in the column. Based on the preliminary estimations of power consumption required for additional CO₂ stripping with the respect to the power consumption of ED stage, it seems that lean solvent CO₂ loading of 0.1 mole/mole provides an optimum for the power input at 25.9 MJ/kg(solvent). Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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16 pages, 2126 KiB

Open AccessArticle

Perfluorosulfonic Acid Membranes Thermally Treated and Modified by Dopants with Proton-Acceptor Properties for Asparaginate and Potassium Ions Determination in Pharmaceuticals

by Anna Parshina, Tatyana Kolganova, Ekaterina Safronova, Alexander Osipov, Ekaterina Lapshina, Anastasia Yelnikova, Olga Bobreshova and Andrey Yaroslavtsev

Membranes 2019, 9(11), 142; https://doi.org/10.3390/membranes9110142 - 30 Oct 2019

Cited by 10 | Viewed by 3025

Abstract

The influence of incorporation of the dopants with proton-acceptor properties into perfluorosulfonic acid cation exchange membranes (MF-4SC and Nafion), and their treatment conditions on the characteristics of Donnan potential (DP)-sensors (analytical signal is the Donnan potential) in the aqueous solutions containing asparaginate and [...] Read more.

The influence of incorporation of the dopants with proton-acceptor properties into perfluorosulfonic acid cation exchange membranes (MF-4SC and Nafion), and their treatment conditions on the characteristics of Donnan potential (DP)-sensors (analytical signal is the Donnan potential) in the aqueous solutions containing asparaginate and potassium ions in a wide pH range was investigated. A silica, surface modified by 3-aminopropyl and 3-(2-imidazolin-1-yl)-propyl groups, was used as the dopant. The membranes were subjected to mechanical deformation and thermal treatment at various relative humidities. The relationship between water uptake and diffusion permeability of membranes subjected to modification and treatment and the cross sensitivity of DP-sensors based on them to counter and co-ions was studied. The multisensory systems for the simultaneous determination of asparaginate and potassium ions in a concentration range from 1.0 × 10⁻⁴ to 1.0 × 10⁻² M and pH range from 4 to 8 were developed. An array of cross-sensitive DP-sensors based on MF-4SC membranes containing 3 wt.% SiO₂ modified by 10 mol.% 3-aminopropyl and 3-(2-imidazolin-1-yl)-propyl was used for the potassium asparaginate hemihydrate and magnesium asparaginate pentahydrate determination in Panangin^® (with an error of 2 and 4%, respectively). Full article

(This article belongs to the Special Issue Ion-Exchange Membranes and Processes)

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