IX Resin Development

Ion exchange was discovered by Thompson & Way in England in 1845 and first commercialised by The Permuit Company in 1913 for process water softening using a process developed in 1905 by the German Scientist Grans.

Cation exchange, based on the sulfonation of coal, was developed in 1935 with the first of the styrene based cation and anion exchange resins coming into the market place in 1940. These styrene-based resins are still being developed and improved with many resin producers in the market place.

In 1987, the Nobel Prize in chemistry was awarded to Charles Pederson, Donald Cram and Jean-Marie Lehm for the development of their host/guest or supramolecular ion exchange. For the first time resins had the ability to extract ions of the same charge through a multi-adsorption mechanism based not only on charge but, additionally, on size, chemistry and geometry. In 1988, the supramolecular technology was commercialised. The advantages of these new generation resins over the conventional styrene resins were:

• Higher pH tolerances
• Improved resistance to fouling
• Longer resin lifetimes
• Greater selectivity
• Some products required no regeneration with acid or base
• Superior kinetics

The University of Montana developed improvements to the supramolecular technology and in 1990 Purity Systems Inc. was formed to commercialise the technology. In December 1999 the inventors were awarded the first of their United States patents for WP-1® ion exchange resin. Technology and marketing rights were transferred to PSI. Further patents were subsequently granted on several other resins. Development of new resins and other novel materials continues today under PSI's Technology License with the University of Montana.

PSI resins are silica composite materials. The silica substrate acts as a robust bead for operating in acidic industrial processes and also provides a highly porous foundation for the attachment of various functional ligands.    

PSI resins are targeted at selected high value metals, or heavy metal impurity removal, and are designed to reject sodium, potassium, magnesium, chloride. Additional advantages that may translate to lower capital and operating costs include:

• Higher flow rates at comparative particle sizes
• Higher tolerance to suspended solids
• Wider pH operating ranges
• No swelling or shrinkage
• Shipped dry
• High temperature tolerance