scholarly journals Factors Influencing the Formation of Sodium Hydroxide by an Ion Exchange Membrane Cell

Batteries ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 34
Author(s):  
Jimmy Aurelio Rosales-Huamani ◽  
Juan Taumaturgo Medina-Collana ◽  
Zoila Margarita Diaz-Cordova ◽  
Jorge Alberto Montaño-Pisfil
Keyword(s):  
Ion Exchange ◽  
Sodium Hydroxide ◽  
Linear Trend ◽  
Electrolytic Cell ◽  
Electrolysis Time ◽  
Operational Parameters ◽  
Graphite Electrodes ◽  
Exchange Membrane ◽  
Membrane Cell ◽  
Production Cell

The present study aimed to evaluate the factors that influence the formation of sodium hydroxide (NaOH) by means of an electrolytic cell with ion exchange membranes. To achieve this experiment, the NaOH production cell had to be designed and built inexpensively, using graphite electrodes. The operational parameters in our study were: initial NaOH concentration, applied voltage, and temperature. All experiments were carried out using model NaCl solutions with a concentration of 40 g/L for 150 min. The results of the experiment were that the NaOH concentration, conductivity, and pH presented an increasing linear trend with the electrolysis time. Finally, it was possible to obtain the efficiency level of the electric current in our investigation, which was an average of 80.2%, that indicated good performance of the built cell.

Microstructure determines water and salt permeation in commercial ion exchange membranes

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>

The role of ion exchange membrane in vanadium oxygen fuel cell

2021 ◽  
Vol 629 ◽  
pp. 119271
Author(s):  
Jiří Charvát ◽  
Petr Mazúr ◽  
Martin Paidar ◽  
Jaromír Pocedič ◽  
Jiří Vrána ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Ion Exchange ◽  
Ion Exchange Membrane ◽  
Exchange Membrane ◽  
Oxygen Fuel

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 Transparent Ion-Exchange Membrane Exhibiting Intense Emission under a Specific pH Condition Based on Polypyridyl Ruthenium(II) Complex with Two Imidazophenanthroline Groups

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 400
Author(s):  
Hajime Kamebuchi ◽  
Satoshi Tamaki ◽  
Atsushi Okazawa ◽  
Norimichi Kojima
Keyword(s):  
Ion Exchange ◽  
Emission Intensity ◽  
Density Functional ◽  
Emission Spectra ◽  
Density Functional Theory Calculations ◽  
Ion Exchange Membrane ◽  
Quantum Yields ◽  
Relative Emission Intensity ◽  
Nafion Film ◽  
Exchange Membrane

The development and the photophysical behavior of a transparent ion-exchange membrane based on a pH-sensitive polypyridyl ruthenium(II) complex, [(bpy)2RuII(H2bpib)RuII(bpy)2](ClO4)4 (bpy = 2,2′-bipyridine, H2bpib = 1,4-bis([1,10]phenanthroline[5,6-d]-imidazol-2-yl)benzene), are experimentally and theoretically reported. The emission spectra of [(bpy)2RuII(H2bpib)RuII(bpy)2]@Nafion film were observed between pH 2 and pH 11 and showed the highest relative emission intensity at pH 5 (λmaxem = 594.4 nm). The relative emission intensity of the film significantly decreased down to 75% at pH 2 and 11 compared to that of pH 5. The quantum yields (Φ) and lifetimes (τ) showed similar correlations with respect to pH, Φ = 0.13 and τ = 1237 ns at pH 5, and Φ = 0.087 and τ = 1014 ns and Φ = 0.069 and τ = 954 ns at pH 2 and pH 11, respectively. These photophysical data are overall considerably superior to those of the solution, with the radiative- (kr) and non-radiative rate constants (knr) at pH 5 estimated to be kr = 1.06 × 105 s−1 and knr = 7.03 × 105 s−1. Density functional theory calculations suggested the contribution of ligand-to-ligand- and intraligand charge transfer to the imidazolium moiety in Ru-H3bpib species, implying that the positive charge on the H3bpib ligand works as a quencher. The Ru-Hbpib species seems to enhance non-radiative deactivation by reducing the energy of the upper-lying metal-centered excited state. These would be responsible for the pH-dependent “off-on-off” emission behavior.

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