Bipolar Membrane (Fumasep, FBM-PK) for Electrodialysis and Electrolysis, CEEBMFBMPK

The Fumasep FBM-PK is a high-performance, reinforced bipolar membrane (BPM) that acts as an "electrochemical water splitter." While standard membranes move existing ions, the FBM-PK is designed to generate new protons (H+) and hydroxide (OH-) ions from water molecules at its internal junction. The PK reinforcement (PEEK mesh) is a critical feature, providing the mechanical stiffness needed to prevent delamination (the layers peeling apart) during high-pressure industrial applications.

The FBM-PK is essentially a "chemical sandwich" consisting of three distinct regions: (1) Cation-Exchange Layer: Selective for cations, allowing H+ to migrate toward the cathode. (2) Anion-Exchange Layer: Selective for anions, allowing OH- to migrate toward the anode. (3) Catalytic Interlayer: A thin region between the two layers containing a catalyst that accelerates the water-splitting reaction.

Bipolar Membrane Electrodialysis (EDBM): This is the most dominant application for the FBM-PK. It is used to convert waste salts into valuable acids and bases. It is able to convert sodium sulfate (Na2SO4) or sodium chloride (NaCl) into H2SO4/HCl and NaOH. It also can be used to help industrial plants recover process chemicals from their wastewater, closing the loop on chemical consumption.

Organic Acid and Amino Acid Recovery: In biotechnology and food processing, acids like Lactic, Citric, or Succinic acid are produced as salts during fermentation. The FBM-PK provides the H+ ions to "acidify" the salt into its pure form without the need to add liquid mineral acids, which would otherwise increase the salt volume of the stream.

Electrochemical Carbon Capture and Conversion: Modern carbon capture systems use the FBM-PK to manage pH gradients. The membrane is used to "regenerate" alkaline CO₂-capture solutions. By splitting water, the H+ ions release the captured CO2 from carbonate solutions, while the OH- ions regenerate the alkaline absorber.

pH Control in "Zero-Gap" Cells: FBM-PK is used in specialized electrochemical reactors to maintain local pH environments. This is particularly useful in water softening or selective metal recovery, where keeping one chamber acidic and the other basic is required to prevent scaling or to promote specific precipitation.

Use Note:

Please follow these guidelines to avoid irreversible membrane damage:

Correct Orientation: The membrane is polarized. The Cation-selective side (usually smoother/darker) must face the Cathode (-). The Anion-selective side must face the Anode (+). Warning: If installed backward, the membrane will not split water; it will act as a standard resistor, heat up rapidly, and likely delaminate (peel apart).

Pretreatment: Soak in 0.5 M NaCl or deionized water for 24 hours before assembly. Hydration: Once the membrane is wet, it must never dry out. If it dries, the different swelling rates of the two polymer layers can cause them to pull apart, destroying the catalytic junction.

Reference:

1. J. Disch, et al., Bipolar Membrane with Porous Anion Exchange Layer for Efficient and Long-Term Stable Electrochemical Reduction of CO2 to CO, Adv Energy Mater., 2023, 13, 2301614.
2. E. Hong, et al., Degradation of a Bipolar Membrane in a Hybrid Acid/Alkali Electrolyzer Studied by X-ray Computed Tomography, ACS Appl. Mater. Interfaces 2024, 16, 39, 52414–52422.