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Ion-Exchange Membranes for the Fabrication of Reverse Electrodialysis Device
Published on: July 20, 2021
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Chromium-Modified Heterogeneous Bipolar Membrane: Structure, Characteristics, and Practical Application in
1Faculty of Chemistry, Voronezh State University, 394018 Voronezh, Russia.
Membranes
|February 25, 2023
Summary
Chromium (III) hydroxide modification enhances bipolar ion exchange membranes for improved sodium sulfate conversion. The modified membranes yield higher acid and base production with reduced energy consumption and salt contamination.
Area of Science:
- Materials Science
- Electrochemistry
- Chemical Engineering
Background:
- Bipolar ion exchange membranes (BIEMs) are crucial for electrochemical processes like electrodialysis.
- The performance of BIEMs can be limited by their inherent properties, necessitating material modification.
- Chromium (III) hydroxide modification is explored as a strategy to enhance BIEM performance.
Purpose of the Study:
- To chemically modify the MB-2 bipolar ion exchange membrane using chromium (III) hydroxide.
- To investigate the impact of this modification on the membrane's morphology, composition, and electrochemical behavior.
- To evaluate the performance of the modified membrane in sodium sulfate conversion.
Main Methods:
- Chemical modification of MB-2 membrane via sequential treatment with chromium (III) salt and alkali.
- Characterization using scanning electron microscopy (SEM) and energy-dispersive analysis (EDA).
- Electrochemical performance evaluation including current efficiency, energy consumption, and salt contamination during sodium sulfate conversion.
Main Results:
- Chromium (III) hydroxide modifier forms a 30-50 micron thick layer at the cation/anion exchange layer boundary.
- Modified MB-2 membrane achieved significantly higher alkali (61%) and acid (57%) yields compared to unmodified MB-2 (38% and 30%).
- Reduced specific electrical conductivity and altered current flow pathways were observed in the modified MK-40 cation-exchange layer.
Conclusions:
- Chromium (III) hydroxide modification effectively enhances bipolar ion exchange membrane performance for sodium sulfate conversion.
- The modified membranes offer improved acid/base yield, reduced energy consumption, and lower salt contamination in products.
- Electrodialysis using chromium-modified bipolar ion exchange membranes is a promising practical application.
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