scholarly journals Preparation of PVA-Based Hollow Fiber Ion-Exchange Membranes and Their Performance for Donnan Dialysis

Membranes ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 4
Author(s):  
Mitsuru Higa ◽  
Yuriko Kakihana ◽  
Takehiro Sugimoto ◽  
Kakuya Toyota
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Anion Exchange ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Fiber Type ◽  
Outer Diameter ◽  
Ion Exchange Membranes ◽  
Donnan Dialysis ◽  
Exchange Membrane

Hollow fiber type cation-exchange (C-HF) membranes and hollow fiber type anion-exchange (A-HF) membranes were prepared from poly (vinyl alcohol) (PVA)-based copolymer with cation-exchange groups and by blending PVA and polycation, respectively, by a gel fiber spinning method. In order to control the water content of the hollow fiber membranes, the membranes were cross-linked physically by annealing, and then cross-linked chemically by using glutaraldehyde (GA) solutions at various GA concentrations. The outer diameter of C-HF and A-HF membranes were ca. 1000 μm and ca. 1500 μm, respectively, and the thickness of the membranes were ca. 170 μm and 290 μm, respectively. Permeation experiments were carried out in two Donnan dialysis systems, which included mixed 0.1 M NaCl and 0.1 M CaCl2/C-HF /3 × 10−4 M CaCl2 and mixed 0.1 M NaCl and 0.1 M NaNO3/A-HF/3 × 10−4 M NaNO3 to examine ionic perm selectivity of the membranes. In the Donnan dialysis experiments using C-HF membranes, uphill transport of the divalent cations occurred, and, in the case of A-HF membranes, uphill transport of NO3− ions occurred. C-HF and A-HF membranes had about half of the flux in the uphill transported ions and also about half of the selectivity between the uphill transport ions and driven ions in comparison with those of the commercial flat sheet cation-exchange membrane (Neosepta® CMX) and anion-exchange membrane (Neosepta® AMX). Yet, IEC of C-HF and A-HF membranes were about one fifth of CMX and less than half of AMX, respectively. Since hollow fiber membrane module will have higher packing density than a flat membrane stack, the hollow fiber type ion-exchange membranes (IEMs) prepared in this study will have a potential application to a Donnan dialysis process.

scholarly journals Custom-Made Ion Exchange Membranes at Laboratory Scale for Reverse Electrodialysis

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 145 ◽  
Author(s):  
Liliana Villafaña-López ◽  
Daniel M. Reyes-Valadez ◽  
Oscar A. González-Vargas ◽  
Victor A. Suárez-Toriello ◽  
Jesús S. Jaime-Ferrer
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Anion Exchange ◽  
Structural Modification ◽  
Anion Exchange Membrane ◽  
Laboratory Scale ◽  
Cation Exchange Membrane ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis ◽  
Exchange Membrane

Salinity gradient power is a renewable, non-intermittent, and neutral carbon energy source. Reverse electrodialysis is one of the most efficient and mature techniques that can harvest this energy from natural estuaries produced by the mixture of seawater and river water. For this, the development of cheap and suitable ion-exchange membranes is crucial for a harvest profitability energy from salinity gradients. In this work, both anion-exchange membrane and cation-exchange membrane based on poly(epichlorohydrin) and polyvinyl chloride, respectively, were synthesized at a laboratory scale (255 c m 2) by way of a solvent evaporation technique. Anion-exchange membrane was surface modified with poly(ethylenimine) and glutaraldehyde, while cellulose acetate was used for the cation exchange membrane structural modification. Modified cation-exchange membrane showed an increase in surface hydrophilicity, ion transportation and permselectivity. Structural modification on the cation-exchange membrane was evidenced by scanning electron microscopy. For the modified anion exchange membrane, a decrease in swelling degree and an increase in both the ion exchange capacity and the fixed charge density suggests an improved performance over the unmodified membrane. Finally, the results obtained in both modified membranes suggest that an enhanced performance in blue energy generation can be expected from these membranes using the reverse electrodialysis technique.

scholarly journals Inorganic Pseudo Ion Exchange Membranes—Concepts and Preliminary Experiments

2018 ◽  
Vol 8 (11) ◽  
pp. 2142 ◽  
Author(s):  
Joost Veerman ◽  
Damnearn Kunteng
Keyword(s):  
Energy Storage ◽  
Ion Exchange ◽  
Cation Exchange ◽  
Anion Exchange ◽  
Silver Chloride ◽  
Anion Exchange Membranes ◽  
Ion Exchange Membranes ◽  
Salt Solutions ◽  
Silver Plate ◽  
Exchange Membrane

Reverse electrodialysis (RED) is a method to produce electricity from the reversible mixing of two salt solutions with different concentrations. RED was first employed for energy generation using sea and river water. New fields of application are energy storage and heat-to-power conversion. In energy storage applications, a stack operates in ED mode during charge and in RED mode during discharge. In a heat-to-power system, the RED stack produces electricity and the outgoing solutions are returned to their original concentrations in a heat-driven regenerator. In both new applications, the salt solutions are circulated and there is a free choice of the combination of salt and membranes for optimal performance. However, classical polymer-based membranes have some disadvantages: they are less suited for operation at higher temperatures, have reduced permselectivity at higher concentrations, and are rather permeable to water, causing an imbalance of the feed waters. We developed a new concept of pseudo-membrane (PM): a metal sheet (sometimes covered with an insoluble salt) on which opposite electrochemical reactions occur at each side of the metal surface. Because a PM is dissolving at one side and growing at the other side during operation, the current should be inverted periodically. We tested a zinc sheet as a pseudo cation exchange membrane for Zn2+ ions and a silver chloride–covered silver plate as a pseudo anion exchange membrane for Cl− ions in three steps. First, a stack was built with Ag/AgCl membranes in combination with normal cation exchange membranes and operated with NaCl solutions. The next stack was based on Zn membranes together with normal anion exchange membranes. This stack was fed with ZnCl2 solutions. Finally, we tested a stack with zinc and Ag/AgCl pseudo-membranes with a ZnCl2 solution. The latter RED system worked; however, after standing for one night, the stack did not function and appeared to be damaged by redox reactions. This failure was the basis for general considerations about the possibilities of ED and RED hybrid stacks, consisting of a combination of classical and pseudo ion exchange membranes. Finally, we consider the possibility of using intercalation electrodes as a pseudo-membrane.

scholarly journals Evaluation of Electrodialysis Desalination Performance of Novel Bioinspired and Conventional Ion Exchange Membranes with Sodium Chloride Feed Solutions

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 217
Author(s):  
AHM Golam Hyder ◽  
Brian A. Morales ◽  
Malynda A. Cappelle ◽  
Stephen J. Percival ◽  
Leo J. Small ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Current Density ◽  
Feed Solution ◽  
Laboratory Scale ◽  
Cation Exchange Membrane ◽  
Limiting Current ◽  
Ion Exchange Membranes ◽  
Experimental Apparatus ◽  
Exchange Membrane

Electrodialysis (ED) desalination performance of different conventional and laboratory-scale ion exchange membranes (IEMs) has been evaluated by many researchers, but most of these studies used their own sets of experimental parameters such as feed solution compositions and concentrations, superficial velocities of the process streams (diluate, concentrate, and electrode rinse), applied electrical voltages, and types of IEMs. Thus, direct comparison of ED desalination performance of different IEMs is virtually impossible. While the use of different conventional IEMs in ED has been reported, the use of bioinspired ion exchange membrane has not been reported yet. The goal of this study was to evaluate the ED desalination performance differences between novel laboratory‑scale bioinspired IEM and conventional IEMs by determining (i) limiting current density, (ii) current density, (iii) current efficiency, (iv) salinity reduction in diluate stream, (v) normalized specific energy consumption, and (vi) water flux by osmosis as a function of (a) initial concentration of NaCl feed solution (diluate and concentrate streams), (b) superficial velocity of feed solution, and (c) applied stack voltage per cell-pair of membranes. A laboratory‑scale single stage batch-recycle electrodialysis experimental apparatus was assembled with five cell‑pairs of IEMs with an active cross-sectional area of 7.84 cm2. In this study, seven combinations of IEMs (commercial and laboratory-made) were compared: (i) Neosepta AMX/CMX, (ii) PCA PCSA/PCSK, (iii) Fujifilm Type 1 AEM/CEM, (iv) SUEZ AR204SZRA/CR67HMR, (v) Ralex AMH-PES/CMH-PES, (vi) Neosepta AMX/Bare Polycarbonate membrane (Polycarb), and (vii) Neosepta AMX/Sandia novel bioinspired cation exchange membrane (SandiaCEM). ED desalination performance with the Sandia novel bioinspired cation exchange membrane (SandiaCEM) was found to be competitive with commercial Neosepta CMX cation exchange membrane.

scholarly journals Thin Reinforced Ion-Exchange Membranes Containing Fluorine Moiety for All-Vanadium Redox Flow Battery

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 867
Author(s):  
Ha-Neul Moon ◽  
Hyeon-Bee Song ◽  
Moon-Sung Kang
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Electrical Resistance ◽  
Vanadium Redox Flow Battery ◽  
Ion Exchange Membranes ◽  
Redox Flow Battery ◽  
Flow Battery ◽  
Exchange Membrane ◽  
Vanadium Redox ◽  
Charge Discharge

In this work, we developed pore-filled ion-exchange membranes (PFIEMs) fabricated for the application to an all-vanadium redox flow battery (VRFB) by filling a hydrocarbon-based ionomer containing a fluorine moiety into the pores of a porous polyethylene (PE) substrate having excellent physical and chemical stabilities. The prepared PFIEMs were shown to possess superior tensile strength (i.e., 136.6 MPa for anion-exchange membrane; 129.9 MPa for cation-exchange membrane) and lower electrical resistance compared with commercial membranes by employing a thin porous PE substrate as a reinforcing material. In addition, by introducing a fluorine moiety into the filling ionomer along with the use of the porous PE substrate, the oxidation stability of the PFIEMs could be greatly improved, and the permeability of vanadium ions could also be significantly reduced. As a result of the evaluation of the charge–discharge performance in the VRFB, it was revealed that the higher the fluorine content in the PFIEMs was, the higher the current efficiency was. Moreover, the voltage efficiency of the PFIEMs was shown to be higher than those of the commercial membranes due to the lower electrical resistance. Consequently, both of the pore-filled anion- and cation-exchange membranes showed superior charge–discharge performances in the VRFB compared with those of hydrocarbon-based commercial membranes.

Determining time-weighted average concentrations of nitrate and ammonium in freshwaters using DGT with ion exchange membrane-based binding layers

2016 ◽  
Vol 18 (12) ◽  
pp. 1530-1539 ◽  
Author(s):  
Jianyin Huang ◽  
William W. Bennett ◽  
David T. Welsh ◽  
Peter R. Teasdale
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Anion Exchange ◽  
Weighted Average ◽  
Ion Exchange Membrane ◽  
Time Weighted Average ◽  
Exchange Membrane

Commercially-available AMI-7001 anion exchange and CMI-7000 cation exchange membranes were utilised as binding layers for DGT measurements of NO3–N and NH4–N in freshwaters.

scholarly journals Enhancing Ion Transfer in Overlimiting Electrodialysis of Dilute Solutions by Modifying the Surface of Heterogeneous Ion-Exchange Membranes

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Natalia Pismenskaya ◽  
Nadezhda Melnik ◽  
Ekaterina Nevakshenova ◽  
Kseniya Nebavskaya ◽  
Victor Nikonenko
Keyword(s):  
Mass Transfer ◽  
Surface Layer ◽  
Ion Exchange ◽  
Cation Exchange ◽  
Water Splitting ◽  
Anion Exchange ◽  
Membrane Surface ◽  
Anion Exchange Membrane ◽  
Cation Exchange Membrane ◽  
Exchange Membrane

The desalination of dilute NaCl solutions with heterogeneous Russian commercial and modified ion-exchange membranes was studied in a laboratory cell imitating desalination channels of large-scale electrodialysers. The modification was made by casting a thin film of a Nafion-type material on the surface of cation-exchange membrane, and by processing with a strong polyelectrolyte the surface of anion-exchange membrane. It was shown that the modifications resulted in an increase of mass transfer coefficient and in a decrease in water splitting rate, both by up to 2 times. The effect of mass transfer growth is explained by higher surface hydrophobicity of the modified membrane that enhances electroconvection. The decrease in water splitting rate in the case of cation-exchange membrane is due to homogenization of its surface layer. In the case of anion-exchange membrane the effect is due to grafting of quaternary ammonium bases onto the original membrane surface layer. The suppression of water splitting favors development of electroconvection. In turn, intensive electroconvection contributes to deliver salt ions to membrane surface and thus reduces water splitting.

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