A Nernst-Planck analysis on the contributions of the ionic transport in permeable ion-exchange membranes to the open circuit voltage and the membrane resistance in reverse electrodialysis stacks

2017 ◽  
Vol 238 ◽  
pp. 134-141 ◽  
Author(s):  
A.A. Moya
Keyword(s):  
Ion Exchange ◽  
Open Circuit Voltage ◽  
Ionic Transport ◽  
Membrane Resistance ◽  
Open Circuit ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis

scholarly journals Use of the Microheterogeneous Model to Assess the Applicability of Ion-Exchange Membranes in the Process of Generating Electricity from a Concentration Gradient

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 406
Author(s):  
Denis Davydov ◽  
Elena Nosova ◽  
Sergey Loza ◽  
Aslan Achoh ◽  
Alexander Korzhov ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Power Density ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Transport Numbers ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis ◽  
Two Samples ◽  
Microheterogeneous Model ◽  
Experimental Values

The paper shows the possibility of using a microheterogeneous model to estimate the transport numbers of counterions through ion-exchange membranes. It is possible to calculate the open-circuit potential and power density of the reverse electrodialyzer using the data obtained. Eight samples of heterogeneous ion-exchange membranes were studied, two samples for each of the following types of membranes: Ralex CM, Ralex AMH, MK-40, and MA-41. Samples in each pair differed in the year of production and storage conditions. In the work, these samples were named “batch 1” and “batch 2”. According to the microheterogeneous model, to calculate the transport numbers of counterions, it is necessary to use the concentration dependence of the electrical conductivity and diffusion permeability. The electrolyte used was a sodium chloride solution with a concentration range corresponding to the conditional composition of river water and the salinity of the Black Sea. During the research, it was found that samples of Ralex membranes of different batches have similar characteristics over the entire range of investigated concentrations. The calculated values of the transfer numbers for membranes of different batches differ insignificantly: ±0.01 for Ralex AMH in 1 M NaCl. For MK-40 and MA-41 membranes, a significant scatter of characteristics was found, especially in concentrated solutions. As a result, in 1 M NaCl, the transport numbers differ by ±0.05 for MK-40 and ±0.1 for MA-41. The value of the open circuit potential for the Ralex membrane pair showed that the experimental values of the potential are slightly lower than the theoretical ones. At the same time, the maximum calculated power density is higher than the experimental values. The maximum power density achieved in the experiment on reverse electrodialysis was 0.22 W/m2, which is in good agreement with the known literature data for heterogeneous membranes. The discrepancy between the experimental and theoretical data may be the difference in the characteristics of the membranes used in the reverse electrodialysis process from the tested samples and does not consider the shadow effect of the spacer in the channels of the electrodialyzer.

scholarly journals Using a microheterogeneous model to assess the applicability of ion-exchange membranes in the process of reverse electrodialysis

2021 ◽  
Vol 8 (2) ◽  
pp. 20218205
Author(s):  
A. N. Korzhov ◽  
A. R. Achoh ◽  
S. A. Loza ◽  
E. N. Nosova ◽  
D. V. Davidov ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Open Circuit Potential ◽  
Transport Number ◽  
Storage Conditions ◽  
Open Circuit ◽  
Transport Numbers ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis ◽  
Two Samples ◽  
Microheterogeneous Model

This paper shows the possibility of using a microheterogeneous model to describe the properties of ion-exchange membranes and calculate the characteristics of a reverse electrodialyzer from the data obtained. We studied the properties of eight samples of heterogeneous cation exchange membranes (two samples of each type of membrane). The samples differed in the year of issue and storage conditions. It is shown that for heterogeneous ion-exchange membranes MK-40 and MA-41, the samples' properties can differ significantly. The counterions transport numbers calculated within the framework of the microheterogeneous model for Ralex membranes differ insignificantly. The counterion transport number in 1 mol/L sodium chloride solution is 0.96 for Ralex CM and 0.98 ± 0.01 for Ralex AMH. For the MK-40 membrane, the transport number in the same solution is 0.94 ± 0.04, and for the MA-41 membrane, it is 0.85 ± 0.1. The possibility of calculating the transport numbers and predicting the open-circuit voltage based on simple physicochemical measurements allows selecting the best membrane pairs for the reverse electrodialysis process. Comparison of the open-circuit potential value calculated using the obtained transfer numbers with experimental data showed that in the case of using Ralex membranes, the difference between the experimental and calculated values is 2%. The calculated value of the open circuit potential was 0.19 V/membrane pair or 1.69 V for the investigated reverse electrodialyzer with nine pair chambers.

scholarly journals The Effect of the NaCl Bulk Concentration on the Resistance of Ion Exchange Membranes—Measuring and Modeling

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1946 ◽  
Author(s):  
Joost Veerman
Keyword(s):  
Ion Exchange ◽  
Membrane Resistance ◽  
Ion Exchange Membranes ◽  
High Concentration ◽  
Reverse Electrodialysis ◽  
Low Concentrations ◽  
Nacl Concentration ◽  
Data Points ◽  
Membrane Contact ◽  
Almost All

Ion exchange membranes are used in different fields of energy and separation technology such as electrodialysis, reverse electrodialysis, and fuel cells. Important aspects are permselectivity, resistance, and water transport. In this paper, we focus on the effect of the bulk NaCl concentration on the membrane resistance. Data from 36 publications containing 145 datasets using 6 different methods for measuring membrane resistance were compared. This study showed that the membrane resistance is dependent on the method of measuring. Two probable causes are identified: the application of reference electrodes and the presence of direct electrode–membrane contact. In addition, three physical and three phenomenological membrane models were tested by fitting these to the datasets. First, fits in the resistance domain were compared with fits in the conductivity domain. Resistance fits are sensitive to fluctuations in low concentrations, whereas fits in the conductivity domain are subject to nonlinear responses at high concentration. Resistance fits resulted in higher coefficients of determination (R2). Then, the six models were compared. The 1-thread model with two fit parameters was in almost all cases a good start. More improvements were difficult to test due to the restricted number of data points in most of the used publications, although this study shows that the so-called Gierke model (with 4 parameters) fits better than the 3-thread model. Phenomenological models were also tested, but they did not lead to much better fits.

scholarly journals The Influence of Concentration and Temperature on the Membrane Resistance of Ion Exchange Membranes and the Levelised Cost of Hydrogen from Reverse Electrodialysis with Ammonium Bicarbonate

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 135
Author(s):  
Yash Dharmendra Raka ◽  
Robert Bock ◽  
Håvard Karoliussen ◽  
Øivind Wilhelmsen ◽  
Odne Stokke Burheim
Keyword(s):  
Ion Exchange ◽  
Waste Heat ◽  
Ammonium Bicarbonate ◽  
Operating Efficiency ◽  
Membrane Thickness ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis ◽  
Ohmic Resistance ◽  
Production Of Hydrogen ◽  
The Impact

The ohmic resistances of the anion and cation ion-exchange membranes (IEMs) that constitute a reverse electrodialysis system (RED) are of crucial importance for its performance. In this work, we study the influence of concentration (0.1 M, 0.5 M, 1 M and 2 M) of ammonium bicarbonate solutions on the ohmic resistances of ten commercial IEMs. We also studied the ohmic resistance at elevated temperature 313 K. Measurements have been performed with a direct two-electrode electrochemical impedance spectroscopy (EIS) method. As the ohmic resistance of the IEMs depends linearly on the membrane thickness, we measured the impedance for three different layered thicknesses, and the results were normalised. To gauge the role of the membrane resistances in the use of RED for production of hydrogen by use of waste heat, we used a thermodynamic and an economic model to study the impact of the ohmic resistance of the IEMs on hydrogen production rate, waste heat required, thermochemical conversion efficiency and the levelised cost of hydrogen. The highest performance was achieved with a stack made of FAS30 and CSO Type IEMs, producing hydrogen at 8.48× 10−7 kg mmem−2s−1 with a waste heat requirement of 344 kWh kg−1 hydrogen. This yielded an operating efficiency of 9.7% and a levelised cost of 7.80 € kgH2−1.

scholarly journals The permselectivity and water transference number of ion exchange membranes in reverse electrodialysis

2017 ◽  
Vol 523 ◽  
pp. 402-408 ◽  
Author(s):  
A. Zlotorowicz ◽  
R.V. Strand ◽  
O.S. Burheim ◽  
Ø. Wilhelmsen ◽  
S. Kjelstrup
Keyword(s):  
Ion Exchange ◽  
Transference Number ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis

Fast and Selective Ionic Transport: From Ion-Conducting Channels to Ion Exchange Membranes for Flow Batteries

2021 ◽  
Vol 51 (1) ◽  
pp. 21-46
Author(s):  
Klaus-Dieter Kreuer ◽  
Andreas Münchinger
Keyword(s):  
Ion Exchange ◽  
Hydration Shell ◽  
Ionic Transport ◽  
Ionic Species ◽  
Steric Effects ◽  
Ion Exchange Membranes ◽  
Specific Chemical ◽  
Aqueous Environments ◽  
Flow Batteries ◽  
Ion Conducting

This review discusses selective and fast transport of ionic species (ions and their associates) through systems as diverse as ion-conducting transmembrane proteins and ion exchange membranes (IEMs) in aqueous environments, with special emphasis on the role of electrostatics, specific chemical interactions, and morphology (steric effects). Contrary to the current doctrine, we suggest that properly balanced ion-coordinating interactions are more important than steric effects for selective ion transport in biological systems. Steric effects are more relevant to the selectivity of ionic transport through IEMs. As a general rule, decreased hydration leads to higher selectivity but also to lower transport rate. Near-perfect selectivity is achieved by ion-conducting channels in which unhydrated ions transfer through extremely short hydrophobic passages separating aqueous environments. In IEMs, ionic species practically keep their hydration shell and their transport is sterically constrained by the width of aqueous pathways. We discuss the trade-off between selectivity and transport rates and make suggestions for choosing, optimizing, or developing membranes for technological applications such as vanadium-redox-flow batteries.

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