scholarly journals Correlation between Computed Ion Hydration Properties and Experimental Values of Sugar Transfer through Nanofiltration and Ion Exchange Membranes in Presence of Electrolyte

Computation ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 42 ◽  
Author(s):  
Alessio Fuoco ◽  
Sylvain Galier ◽  
Hélène Roux-de Balmann ◽  
Giorgio De Luca
Keyword(s):  
Ion Exchange ◽  
Hydration Number ◽  
Ionic Exchange ◽  
Hydration Energy ◽  
Ion Exchange Membranes ◽  
Ion Hydration ◽  
Hydration Properties ◽  
Solute Fluxes ◽  
Hydration Energies ◽  
Experimental Values

The widespread use of nanofiltration and electrodialysis membrane processes is slowed down by the difficulties in predicting the membrane performances for treating streams of variable ionic compositions. Correlations between ion hydration properties and solute transfer can help to overcome this drawback. This research aims to investigate the correlation between theoretically evaluated hydration properties of major ions in solution and experimental values of neutral organic solute fluxes. In particular, ion hydration energies, coordination and hydration number and the average ion-water distance of Na+, Ca2+, Mg2+, Cl− and SO42− were calculated at a high quantum mechanics level and compared with experimental sugar fluxes previously reported. The properties computed by simple and not computationally expensive models were validated with information from the literature. This work discusses the correlation between the hydration energies of ions and fluxes of three saccharides, measured through nanofiltration and ionic-exchange membranes. In nanofiltration, the sugar flux increases with the presence of ions of increasing hydration energy. Instead, inverse linear correlations were found between the hydration energy and the sugar fluxes through ion exchange membranes. Finally, an empirical model is proposed for a rough evaluation of the variation in sugar fluxes as function of hydration energy for the ion exchange membranes in diffusion experiments.

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.

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

Interpolymer ion exchange membranes for CapMix process

Desalination ◽  
2020 ◽  
Vol 482 ◽  
pp. 114384
Author(s):  
Katarzyna Smolinska-Kempisty ◽  
Anna Siekierka ◽  
Marek Bryjak
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Membranes

A comprehensive review on the synthesis and applications of ion exchange membranes

Chemosphere ◽  
2021 ◽  
pp. 130817
Author(s):  
Shanxue Jiang ◽  
Haishu Sun ◽  
Huijiao Wang ◽  
Bradley P. Ladewig ◽  
Zhiliang Yao
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Membranes ◽  
Comprehensive Review

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.

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