Electrodialysis - Denki Touseki

When dialysis is performed on a colloid or polymer solution containing electrolytes, a direct current is passed through a membrane to increase the rate of dialysis removal of electrolytes. Currently, it is also used when handling only electrolyte solutions. Its applications include desalination, concentration, purification, washing, separation, recovery, and other operations. Electrodialysis usually uses a multi-chamber electrolytic cell separated by several membranes, and its efficiency depends on the performance of the membrane used. Membranes are divided into negative and positive membranes depending on the type of charge they have, the former being permeable to cations and the latter being permeable to anions. The selective permeability of ions and electrical conductivity are important electrochemical properties for evaluating the performance of a membrane. Negative membranes include parchment paper, collodion, cellophane, and unglazed boards, while positive membranes include bladder membranes, silk cloth, felt, and chrome gelatin membranes, but most of these do not have sufficient electrochemical properties. Ion exchange resin membranes have excellent properties and are used as diaphragms for industrial electrodialysis. [See other terms] Ion exchange membranes

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

電解質を含んだコロイドや高分子溶液を透析するとき，隔膜を通して直流を流し，電解質の透析除去速度を高める操作．現在では，電解質溶液のみを取り扱う場合にも用いられる．そして，その応用は脱塩，濃縮，精製，洗浄，分離，回収などの諸操作にわたっている．電気透析には通常数枚の隔膜で分離された多室電解槽が用いられ，その能率は用いられる隔膜の性能にかかっている．隔膜は膜のもつ電荷の種類により，陰性膜および陽性膜に分かれ，前者はカチオン透過性，後者はアニオン透過性を示す．このイオンの選択透過性と電気伝導率は，隔膜の性能を評価するうえで重要な電気化学的性質である．陰性膜にはパーチメント紙，コロジオン，セロハン，素焼き板など，陽性膜には，膀胱膜，絹布，フェルト，クロムゼラチン膜などがあるが，これらの大部分のものは，その電気化学的性質が十分ではない．イオン交換樹脂膜は，その性質がすぐれ，工業的な電気透析用隔膜として用いられる．[別用語参照]イオン交換膜

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