High Performance Ion Exchange Media

NNL is interested in developing ion exchange media with enhanced performance characteristics. Traditional mixed bed resins have an operating temperature range limited by the anion resin thermal stability. Anion capacity rapidly degrades at temperatures above ~140 °F. For applications in ultrapure water with very low ionic contaminates, thermal degradation of the anion capacity can be the limiting factor for media bed lifetime. The need to cool the water to be purified also creates parasitic losses for thermal hydraulic systems that operate at high temperatures. To overcome these challenges, NNL is seeking proposals to enhance critical capabilities of ion exchange media, including the following:

• Improved thermal stability to enable increased normal operating temperature (>~200 °F) and/or longer-lived media beds
• Increased total mixed bed ion exchange capacity (>0.8 milliequivalents per milliliter)

Prospective offerings should be accompanied by a description of the changes to typical resin characteristics (e.g. chemistry, structure) that would enable these improvements. The selected materials will be tested for both initial capacity and remaining capacity after being subjected to thermal treatments at varying temperatures and durations.

Candidates for consideration should also meet the other requirements in the Military Specification for ion exchange resins (MIL-DTL-24119D(SH)). The mixed resin should consist of cation resins in both the hydrogen and ammonium form and anion resins in the hydroxide form. Alternatively, a different type of media other than resin made from cross-linked polystyrenes could offer these improved capabilities and are encouraged to be submitted as well.

The ability to capture and retain particulates in the colloidal (sub-micron) to tens of microns range is also desirable. Proposals should provide discussion of total bed capacity for particulates in this range and potential ways to enhance this capacity.