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History of Electrodeionization

Electrodeionization (EDI) history extends back to the mid-1970’s in the USA. Possibly back to Argonne National Labs in the 1950’s as a scientific novelty. However, the first working EDI modules were made by Harry O’Hare in 1977 and 1978, and were tested by the Southern Research Institute (SRI).  The concept was “filled-cell ED”, an attempt to use the ED concept to accomplish other goals.

First electrodeionization module 1977
First electrodeionization module 1977

One goal of “electronic water purification” was to do continuous membrane softening of water. Another was to deionize water, which ED could not do effectively.

Electrodialysis (ED) was first made successful by Ionics Corp in the 1950’s and 1960’s with the advent of ion-selective membranes and the concept of EDR. However, while EDR is beneficial for making drinking water from seawater it was not good for deionizing water, replacing mixed bed ion exchange resins, or for making ultrapure water.

“Filled-cell ED” was developed both by a group under Arthur Goldstein at Ionics in Massachusetts and by O’Hare in California. Goldstein and Ionics abandoned the concept as not commercially interesting, but O’Hare persisted. Harry O’Hare formed “HOH Water Technologies” in 1979 based on his success in the lab. He then applied for the first EDI patent in 1981, which was granted in 1984.

The Ionics group quit and moved to Millipore, just up Highway 128 from Ionics, where they were supported in the development of EDI. This group began patenting EDI in 1985-86 (Oren et al.). Millipore divided its EDI technology in to laboratory (Elix, Millipore) and industrial (Ionpure, which is spun out as the Ionpure division in the mid-1990’s).

O’Hare pioneered and patented several novel concepts for EDI:

  • thin cell EDI, for better performance (Electropure and Millipore fought this in court)
  • filled concentrate, for electrical efficiency (Electropure found it fouled too easily, and abandoned the “all-filled” design)
  • cylindrical EDI, for better sealing

    Cylindrical electrodeionization module development
    Cylindrical electrodeionization module development

HOH Water Technologies later went public, and was eventually renamed Electropure Inc., after a change in control. In 2005, SnowPure Water Technologies was formed as a management buyout of the electrodeionization portion of Electropure Inc., separating from Micro-Imaging Technology (Laserpure).

Early EDI models were expensive to make and sell. Early adopters of the electrodeionization technology built electrodeionization systems mostly for high-value-added applications like pharmaceutical water.

Robert Glegg, who built Glegg Water and started E-Cell Corporation, can be credited will selling the vision worldwide that “all mixed beds will be replaced by electrodeionization”. He sold licenses and used his charisma and influence to propagate this notion. Glegg purchased a license from HOH, and from this and collaboration with Asahi in Japan developed the E-Cell™ EDI product line.

Electrodeionization module history and development
Electrodeionization module history and development

Today, SnowPure’s brand Electropure™, Suez’s brand E-Cell™, and Evoqua’s brand Ionpure™ dominate the electrodeionization module markets worldwide. SnowPure offers a variety of EDI products from laboratory to power generation.

Electropure electrodeionization modules 2018
Electropure electrodeionization modules 2019