SUEZ Water - Water Technologies & Water

Ionics Ion Exchange Membranes

Ionics ion exchange membranes are homogeneous ion exchange films cast in sheet form on reinforcing synthetic fabrics such as polypropylene and polyester cloth. The membranes are typically used in Ionics ED and EDR stacks but are also available for sale individually.

Ionics* membranes are made with monomer formulations developed by our membrane chemists cast continuously on various support structures. They are each selective for allowing either anions or cations to pass through them. SUEZ - Water Technologies & Solutions has been making homogeneous ion exchange membranes for 70 years since the invention of the technology by Ionics Corp. in 1948.


General Membrane Characteristics

  • Low electrical resistance
  • High permselectivity
  • Rugged construction and high burst strength
  • Excellent long-term stability up to 70°C
  • Long-term resistance to aqueous acid solutions
  • High dimensional stability
  • High resistance to fouling by organic materials


Ionics ion exchange membranes have certifications below. See individual membrane fact sheets for specific certifications.

  • NSF 61 - Drinking Water
  • 21CFR175,176,177,178,182 – Food Contact Materials
  • EU 1935/2004 – Food Contact Materials
  • EU 10/2001 - Food Contact Materials
  • BSE/TSE EMEA/410/1 – No Materials of Animal Origin

Membranes by Application

Nonwoven Cloth Membranes

To improve performance of our ion exchange membranes, we discontinued use of a woven acrylic cloth and replaced it with a nonwoven polyester cloth. First, the nonwoven cloth membranes have lower electrical resistance. This means that when used, the voltage required to achieve a target product TDS can be lower. This can result in lower power consumption by the ED or EDR plant. Since the membranes are made of a nonwoven cloth, they will not generate “strings” hanging on the exterior of the stack as the edge of the membranes become dry, as happens with the use of woven cloths.

Here is an enhanced picture showing the texture comparison of the two membrane types: Woven acrylic cloth Nonwoven polyester cloth These membranes are NSF 61 certified as the woven acrylic cloth membranes were.

Nonwoven Polypropylene Membranes

SUEZ will also convert the remaining membranes which use woven cloths to a nonwoven structure. AR103P and CR61P are cast on woven polypropylene cloth, and typically used in food and beverage applications. These membranes will be directly replaced by AR103N and CR61N. The ‘N’ type cloth is a thin nonwoven polypropylene cloth that will provide a superior membrane product with lower power consumption and smoother surface to reduce scaling and other deposits. SUEZ will work with all current customers to ensure a smooth transition to the new membranes. 

Thinner Membranes

As part of our new generation of ED and EDR stack designs, the Ionics V Series, SUEZ is producing thinner membranes that fit in our recessed spacer design to further improve electrical resistance for more efficient ED and EDR operation. These membranes can also be used in existing MkIV stack hardware to provide lower power consumption and/or expanded capacity. 750 cells of membranes will fit in the space that 600 cells of the thicker membranes occupy.


Fact Sheets

Membrane Selection Guide

SUEZ’s ion exchange membranes are ion selective membranes comprised of cross-linked co-polymers of vinyl monomers and containing quaternary ammonium anion exchange groups or sulfonic acid cation exchange groups.

See the Ionics Ion Exchange Membranes Factsheet

Membrane Fact Sheets