Introduction to electrodialysis technology and its development background来源： 作者: 阅读：93318 网友评论0条 Updated: 2011-03-03 14:35 Source: Author: Read: 93318 2010 0 comments
Electrodialysis (ED) technology is a type of membrane separation technology that alternates anion and cation exchange membranes between positive and negative electrodes and separates them with a special separator to form a desalination (desalination) and The two systems of concentration, under the action of a DC electric field, use the potential difference as the driving force, and use the selective permeability of the ion exchange membrane to separate the electrolyte from the solution, thereby achieving the concentration, desalination, refining and purification of the solution.
The research on electrodialysis technology began in Germany.In 1903, Morse and Pierce placed the two electrodes inside the dialysis bag and the external solution, and found that charged impurities could be quickly removed from the gel.In 1924, Pauli used Principle, improved Morse's experimental device, trying to reduce polarization and increase mass transfer rate. But it wasn't until Juda's first trial production of a highly selective ion-exchange membrane in 1950 that the electrodialysis technology entered the practical stage, which experienced three major innovations:
(1) Application with selective ion exchange membrane;
(2) Design a multi-compartment electrodialysis module;
(3) Adopt frequent inverted operation mode.
Nowadays, the performance of various aspects of the ion exchange membrane and the structure of the electrodialysis device are constantly innovated and improved. The electrodialysis technology has entered a new stage of development, and its application prospects are also broader.
The electrodialyzer is composed of main parts such as a separator, an ion exchange membrane, an electrode, and a clamping device. Ion exchange membranes have selective permeability to ions with different charges. The cation membrane only allows cations to pass through, and the anion membrane allows only anions to pass through, preventing cations from passing. Under the action of an external DC electric field, the ions in the water migrate directionally. Since the electrodialyzer is composed of multiple compartments, the anions and cations in the dilute compartment migrate to the adjacent thick compartment, thereby desalinating the brine. In the food and pharmaceutical industries, electrodialysis can be used to remove electrolyte ions from organic solutions. It has been successfully used in whey desalination, sugar desalination, and amino acid purification.
Electrodialysis, as an emerging membrane separation technology, plays an important role in natural water desalination, seawater concentration for salt production, and wastewater treatment. It has become a more mature water treatment method.
|Electrodialysis feedwater treatment equipment|
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