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Bipolar Electrodialysis Membrane Layers

Bipolar electrodialysis membranes (EDBM) are specialized membranes used in bipolar electrodialysis processes to enhance the separation of ions.


The BPED membranes are designed to facilitate the conversion of salts into their corresponding acids and bases, making them highly effective for various industrial applications.

The bipolar membranes are composed of two distinct layers: a cation-exchange layer and an anion-exchange layer. This unique structure enables the simultaneous separation and transformation of ions, making it a powerful tool for a range of industrial applications.

Bipolar Electrodialysis Membranes Working Principle

The working principle of bipolar electrodialysis membranes is based on the phenomenon of water dissociation. 


The bipolar layer in the middle creates a junction where water splitting occurs, generating hydrogen ions (H⁺) and hydroxide ions (OH⁻), further facilitating ion separation and transformation.​​

The bipolar electrodialysis membrane layers are formed by two combined ion exchange membranes: Cation-Exchange Membranes (CEMs) and Anion-Exchange Membranes (AEMs). Depending on the charge, in electrodialysis applications, these membranes allow for negatively charged ions (anions) to pass through while positively charged ions (cations) or vice versa.

These two layers combined create the Bipolar Membrane (BPM) which is the key component of bipolar electrodialysis.

In the picture below we can find an example of the working principle of DESALT bipolar electrodialysis membrane layers, formed by two single cation and anion ion-exchange membrane layers:

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BIPOLAR Electrodialysis Membrane Stack and Modules Working Principle and Applications

Electrodialysis with bipolar membrane (EDBM) is a technology capable of producing acid and base solutions from the corresponding saline solution used as a feed.


The repeating unit (typically named triplet) of an EDBM system consists of a sequence of three channels hosting the electrolyte solutions separated by three ion-exchange membranes: anion (AEM), cation (CEM), and bipolar (BPM).  Furthermore, two electrodes and an electrode rinse solution (ERS) are used to convert electricity into ionic current.


When an electric potential is applied between the two electrodes, the water dissociation reaction takes place in the interlayer of the bipolar membrane, resulting in the production of protons and hydroxide ions. Due to the applied electric field, the ions are driven to opposite sides of the BPM based on their charge. Consequently, acidic and alkaline solutions are produced. A schematic representation of an EDBM stack applicaiton is provided below:

BPED NA2SO4export.png

In the drawing above, DESALT bipolar membrane stacks are used for Sodium sulphate recovery using bipolar electrodialysis (BPED).


Bipolar electrodialysis is an innovative and efficient process that capitalizes on the unique properties of bipolar membranes to transform and separate ionic species. This method is particularly valuable in industries where sodium sulphate is either a valuable product or a waste by-product that needs to be managed.

Some more applications of bipolar electrodialysis (EDBM) are found in the lithium industry, desalination plants, and CO2 capturing plants. For more information about the use of bipolar electrodialysis for your industry, kindly get in touch with our team.

Water Texture

Bipolar Electrodialysis Membrane Features


Ion-Exchange Capacity

  • High capacity for efficient ion separation and transformation.

  • Optimized for selective passage of specific ions, facilitating precise chemical processes.



  • Long-lasting performance with resistance to chemical and mechanical degradation.

  • Capable of withstanding harsh operating conditions and repeated cycling.


Electric Resistance

  • Low electric resistance to ensure efficient ion transport and minimize energy consumption.

  • Designed to provide optimal conductivity, enhancing overall process efficiency.


Advanced Tech

  • Incorporation of cutting-edge materials and design features.

  • Enhanced water-splitting capabilities for improved conversion of salts into acids and bases.

Bipolar Electrodialysis Membrane Layers Specifications

For all the technical data about our bipolar electrodialysis membrane layers and for more info about DESALT-EDBM test equipment you can get in touch with our team. We will guide you in the selection of the most suitable BPM and test unit for your application.

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