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There isn't anyone anywhere who hasn't enjoyed the sweet taste of their
favorite soft drink on a hot day. However, few people know that the satisfying
flavor of those drinks is made possible in large part because of ion exchange
resins, manufactured by The Dow Chemical Company.
DOWEX resins are used in corn sweetener processing, and most of those sweeteners
are used in the global, multi-billion dollar soft drink industry. These
resins remove unwanted ions and other contaminants that occur in the syrup
stream. Separation resin allows the production of enriched fructose by separating
the syrup into bands as it moves through a column of resin beads. In addition,
Dow adsorbent replaces or supplements activated carbon systems, removing
impurities that cause off colors or bad flavors.
How Ion Exchange Resins Work
Ion exchange resins are charged to remove unwanted ions from the syrup stream.
This is an exact science that involves controlling bead size, porosity,
polymer cross-link, and other qualities that control how well the resin
purifies syrup. Ion exchange resins work by exchanging one type of ion for
another that has a greater attraction to active sites on the polymer chain.
For example, DOWEX 88 strong acid cation resin is initially loaded with
positive hydrogen ions. When syrup is pumped through a resin bed, the resin
will exchange its hydrogen ions for less desirable cations like calcium,
sodium, magnesium, and potassium. All of these elements occur naturally
in syrup, but are detrimental to its flavor. Because resins are porous,
ion exchange takes place within the beads and on the surface as the syrup
stream moves through resin. Deashing resins are called macroporous beads
because of the relatively large pores that allow syrup components to move
freely through the beads for efficient ion exchange.
The Dow Liquid Separations business is part of the Dow Specialty Chemicals
business. Dow is a leading science and technology company that provides
chemical, plastic and agricultural products and services to many essential
consumer markets. With annual sales of $19 billion, Dow serves customers
in 162 countries and a wide range of markets that are vital to human progress,
including food, transportation, health and medicine, personal and home care,
and building and construction, among others. Committed to the principles
of sustainable development, Dow and its 39,000 employees seek to balance
economic, environmental and social responsibilities.