De Novo Ion-Exchange Membranes Based on Nanofibers

The unique functions of nanofibers (NFs) are based on their nanoscale cross-section, high specific surface area, and high molecular orientation, and/or their confined polymer chains inside the fibers. The introduction of ion-exchange (IEX) groups on the surface and/or inside the NFs provides de novo ion-exchangers. In particular, the combination of large surface areas and ionizable groups in the IEX-NFs improves their performance through indices such as extremely rapid ion-exchange kinetics and high ion-exchange capacities. In reality, the membranes based on ion-exchange NFs exhibit superior properties such as high catalytic efficiency, high ion-exchange and adsorption capacities, and high ionic conductivities. The present review highlights the fundamental aspects of IEX-NFs (i.e., their unique size-dependent properties), scalable production methods, and the recent advancements in their applications in catalysis, separation/adsorption processes, and fuel cells, as well as the future perspectives and endeavors of NF-based IEMs.

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Shape of Confined Polymer Chains

Journal de Physique II ◽

10.1051/jp2:1997136 ◽

1997 ◽

Vol 7 (3) ◽

pp. 433-447 ◽

Cited By ~ 29

Author(s):

C. E. Cordeiro ◽

M. Molisana ◽

D. Thirumalai

Keyword(s):

Polymer Chains ◽

Confined Polymer ◽

Confined Polymer Chains

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Microstructure determines water and salt permeation in commercial ion exchange membranes

10.26434/chemrxiv.6987248.v3 ◽

2018 ◽

Author(s):

Ryan Kingsbury ◽

Shan Zhu ◽

Sophie Flotron ◽

Orlando Coronell

Keyword(s):

Energy Efficiency ◽

Ion Exchange ◽

Electrolyte Solutions ◽

Polymer Chains ◽

Salt Transport ◽

Mixing Energy ◽

Electrochemical Processes ◽

Highly Correlated ◽

Salt Diffusion ◽

Exchange Membrane

Ion exchange membrane (IEM) performance in electrochemical processes such as fuel cells, redox flow batteries, or reverse electrodialysis (RED) is typically quantified through membrane selectivity and conductivity, which together determine the energy efficiency. However, water and co-ion transport (i.e., osmosis and salt diffusion / fuel crossover) also impact energy efficiency by allowing uncontrolled mixing of the electrolyte solutions to occur. For example, in RED with hypersaline water sources, uncontrolled mixing consumes 20-50% of the available mixing energy. Thus, in addition to high selectivity and high conductivity, it is desirable for IEMs to have low permeability to water and salt in order to minimize energy losses. Unfortunately, there is very little quantitative water and salt permeability information available for commercial IEMs, making it difficult to select the best membrane for a particular application. Accordingly, we measured the water and salt transport properties of 20 commercial IEMs and analyzed the relationships between permeability, diffusion and partitioning according to the solution-diffusion model. We found that water and salt permeance vary over several orders of magnitude among commercial IEMs, making some membranes better-suited than others to electrochemical processes that involve high salt concentrations and/or concentration gradients. Water and salt diffusion coefficients were found to be the principal factors contributing to the differences in permeance among commercial IEMs. We also observed that water and salt permeability were highly correlated to one another for all IEMs studied, regardless of polymer type or reinforcement. This finding suggests that transport of mobile salt in IEMs is governed by the microstructure of the membrane, and provides clear evidence that mobile salt does not interact strongly with polymer chains in highly-swollen IEMs. <br>

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Ion Exchange Kinetics. A Nonlinear Diffusion Problem

The Journal of Chemical Physics ◽

10.1063/1.1744149 ◽

1958 ◽

Vol 28 (3) ◽

pp. 418-424 ◽

Cited By ~ 228

Author(s):

F. Helfferich ◽

M. S. Plesset

Keyword(s):

Ion Exchange ◽

Nonlinear Diffusion ◽

Diffusion Problem ◽

Ion Exchange Kinetics ◽

Exchange Kinetics

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Sodium, Silver and Lithium-Ion Conducting β″-Alumina + YSZ Composites, Ionic Conductivity and Stability

Crystals ◽

10.3390/cryst11030293 ◽

2021 ◽

Vol 11 (3) ◽

pp. 293

Author(s):

Liangzhu Zhu ◽

Anil V. Virkar

Keyword(s):

Ion Exchange ◽

Electrochemical Impedance ◽

Ionic Conductivities ◽

Lithium Ion ◽

Co2 Corrosion ◽

Ionic Conductors ◽

Ion Conductor ◽

Sensor Applications ◽

Potential Applications ◽

Ion Conducting

Na-β″-alumina (Na2O.~6Al2O3) is known to be an excellent sodium ion conductor in battery and sensor applications. In this study we report fabrication of Na- β″-alumina + YSZ dual phase composite to mitigate moisture and CO2 corrosion that otherwise can lead to degradation in pure Na-β″-alumina conductor. Subsequently, we heat-treated the samples in molten AgNO3 and LiNO3 to respectively form Ag-β″-alumina + YSZ and Li-β″-alumina + YSZ to investigate their potential applications in silver- and lithium-ion solid state batteries. Ion exchange fronts were captured via SEM and EDS techniques. Their ionic conductivities were measured using electrochemical impedance spectroscopy. Both ion exchange rates and ionic conductivities of these composite ionic conductors were firstly reported here and measured as a function of ion exchange time and temperature.

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Ion exchange kinetics of magnetic alginate ferrogel beads produced by external gelation

Carbohydrate Polymers ◽

10.1016/j.carbpol.2014.04.009 ◽

2014 ◽

Vol 111 ◽

pp. 198-205 ◽

Cited By ~ 10

Author(s):

Vânea Ferreira Torres Teixeira ◽

Nádia Rosa Pereira ◽

Walter Ruggeri Waldman ◽

Ana Luiza Cassiano Dias Ávila ◽

Victor Haber Pérez ◽

...

Keyword(s):

Ion Exchange ◽

External Gelation ◽

Ion Exchange Kinetics ◽

Exchange Kinetics ◽

Kinetics Of

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Kinetics of alkali ion exchange of irradiated glasses

MRS Proceedings ◽

10.1557/proc-792-r2.5 ◽

2003 ◽

Vol 792 ◽

Author(s):

Michael I. Ojovan ◽

William E. Lee

Keyword(s):

Ion Exchange ◽

External Irradiation ◽

Glass Temperature ◽

Ion Exchange Kinetics ◽

Radiation Induced ◽

Exchange Kinetics ◽

Induced Changes ◽

Kinetics Of ◽

Alkali Ion

ABSTRACTThe kinetics of alkali ion exchange of irradiated glasses were investigated using the structural energy barrier model for ion exchange of glasses. Derived rates of alkali ion exchange depend both on irradiation dose D(Gy) and dose rate q(Gy/s) illustrating that some effects cannot be simulated by external irradiation and require in-situ measurements. Higher D and q lead to increased ion exchange rates. Significant changes occur in the activation energies demonstrating a 4 – 6 times decrease depending on glass composition. Radiation-induced changes are higher at relatively low temperatures and are diminished by increased glass temperature. Numerical estimations show that changes in alkali ion exchange kinetics occur at D far below damaging doses.

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