News | April 17, 2006

DOWEX Ion Exchange Resins From Dow Liquid Separations Address Water Needs In Municipalities And In Commercial Applications

Selective Removal Technology Leads to High Removal Rates of Specified Substances

Midland, MI - As municipalities strive to comply with the United States Environmental Protection Agency (EPA) standards for reduced contaminant levels in drinking water in public water systems, and demand increases for mineral-free water for use in commercial and consumer applications, DOWEX ion exchange resins from Dow Liquid Separations, a business of The Dow Chemical Company, are at the forefront.

Based on Dow's advanced ion exchange treatment technologies, the diverse portfolio of DOWEX resins are able to selectively remove a wide variety of substances -- from nitrates to radium to spot-creating minerals -- often to levels well below the minimum requirements.

"As EPA regulations for trace contaminants in drinking water tighten and public health concerns for the presence of these chemicals rise, DOWEX resins are helping address these global needs for water treatment," said Brian Powers, DOWEX ion exchange marketing manager for the Americas. "Ion exchange is one of the most important technologies for selective contaminant removal from drinking water, and DOWEX resins offer several advantages, including higher capacity and improved selectivity."

At the Water Quality Association Aquatech show held in Rosemont, Illinois on March 29-31, 2006, Dow Liquid Separations highlighted the following products from its robust portfolio of ion exchange resins:

  • DOWEX NSR-1 resin, a triethylamine based nitrate selective resin from Dow Liquid Separations, used for the removal of nitrate from drinking water, is currently helping municipalities in the United States meet the EPA's Maximum Contaminant Level (MCL) value for nitrate of 10 parts per million (ppm) for public water systems.
  • DOWEX NSR-1 resins offer better selectivity for nitrates over other anions like sulfates and chlorides, allowing for more effective nitrate removal from drinking water. Hence, DOWEX NSR-1 is more suitable for cases in which the ratio of sulfate to nitrate is moderate to high, as compared to type I or type II strong base anion resins. Additionally, the DOWEX NSR-1 resin is certified under NSF/ANSI STD 61, which sets the standard for all materials that contact drinking water, making it the resin of choice for nitrate retention and removal from water streams. Additionally, DOWEX NSR-1 offers improved capacity and does not contribute more nitrates than were originally in the water.
  • DOWEX resins also play a key role in a number of metal management applications, including the removal of radium from groundwater. DOWEXTM RSC (Radium Selective Complexer) Resin, another ion exchange product from Dow Liquid Separations, is extremely effective at removing radium and barium from drinking water, helping municipalities comply with the EPA's MCL for radium and barium, which is 5pCi/L for the combined isotopes.
  • A full range of DOWEX resins are available for perchlorate removal, ranging from high capacity, low installation cost options to highly selective resins with much greater affinity for perchlorate and longer operating life.
  • DOWEX resins are also being used in a wide range of additional potable water applications, including trace contaminant removal of uranium, hexavalent chromium, chlorinated organics, solvents, and heavy metals.

Consumers Prefer Spot-Free
Dow's ion exchange resins also play a large role in time-saving solutions for consumer applications. DOWEX MB ion exchange resin is a 1:1 equivalent mixture of strong acid cation and strong base anion exchange resin. The product is a ready-to-use mixed resin for the economical production of spot-free water, water without the dissolved minerals whose residue is responsible for the occurrence of spots on surfaces. DOWEX MB typically produces between 500 and 700 gallons of spot free water/ cubic foot and is the ideal choice for single-use industrial applications and is typically discarded upon exhaustion.

"Consumer demand for time-saving solutions has expanded the way we view consumer products. Consumer applications that require separate rinse and dry steps are being simplified through the use of ion exchange resins for spot-free rinse. With mineral-free water in the rinse step, consumers can have a spot-free appearance while skipping the drying step. Home products and systems for window washing, car washing and pressure washing can all offer time-saving solutions by incorporating DOWEX MB," said Powers.

SOURCE: Dow