Fumasep E-620(K) | 20 micron CEM

Fumasep® E-620 (K) is a non-reinforced cation exchange membrane (CEM) with very low resistance, high selectivity, and high stability across the full pH range (0–14). With a thickness of approximately 20 µm, it is designed for electrochemical applications requiring low ionic resistance and excellent dimensional stability.

Fumasep E-620 (K) membrane comes in either a 10 cm × 10 cm or 20 cm × 30 cm size sheet.

Note: Fumatech membranes are highly sensitive to differences in humidity and moisture content. Therefore, the membranes can vary by ±0.5 cm from the original cut sizes. Due to this sensitivity, the manufacturer expects wrinkles to potentially form. Soaking the membranes in deionized water will return the membranes to the full-size planar state according to the manufacturer.

Key Features

• Applications: Capacitive deionization (CDI) and other electrochemical applications
• Cation Exchange Membrane (non-reinforced)
• Stability Range (pH) at 25 °C: 0 – 14
• Thickness (dry): 17 – 23 micrometers (0.67 – 0.91 mil)
• Very low area resistance: < 1.0 Ω·cm² (in Na⁺ form)
• High selectivity: > 96%
• Available sizes: 10 cm × 10 cm, 20 cm × 30 cm

Fumasep E-620 (K) Technical Specification Sheet

Delivery
The membrane is a slightly brown color, delivered on a backing layer (colorless rigid PET foil). Carefully separate the membrane from the backing layer before use.

Handling and Storage
Keep the membrane package closed/sealed when unused. Store, handle, and process the membrane in a clean and dust-free area. Use only new and sharp knives or blades when cutting the membrane. Always wear protective gloves when handling the membrane. Handle with care — be sure not to puncture, crease, or scratch the membrane. Otherwise, leaks will occur. All surfaces that may come into contact with the membrane during inspection, storage, pretreatment, and mounting should not have sharp edges or angles.

Dry form: Storage for long time scales (> 12 months) may be done in the dry state (sealed container).
Wet form: Storage for short and medium time scales (hours up to several weeks) may be done in unsealed containers in 0.5 – 1.5 wt% NaCl solution or comparable neutral pH electrolytes. For longer storage periods, a sealed container is recommended using the aforementioned electrolyte with additional biocide to avoid biological fouling.

Pretreatment
The membrane is supplied in K-form and dry state, stabilized with polyethylene glycol (PEG) as protection against embrittlement. The PEG can be easily removed by soaking in deionized water (before or after assembly). If additional cleaning is required, rinse the membrane in either the application solution or deionized water according to the application requirement.

Important: Do not let the membrane dry out once hydrated, as micro-cracks may occur during shrinkage. Membranes will expand and contract based on water/electrolyte content.

If you have any concerns about storage, chemical stability, or pretreatment, please feel free to contact us for more information.