《DOWEX MARATHON WBA-2 Engineering Information》.pdf

Dow Liquid Separations DOWEX Ion Exchange Resin DOWEX MARATHON WBA-2 Engineering Information July 2003 DOWEX MARATHON WBA-2 Weak Base Anion Exchange Resin General Information DOWEX* MARATHON* WBA-2 resin is a high capacity, macroporous, weak base anion exchange resin of uniform bead size distribution. It is based on a styrene-divinylbenzene copolymer matrix with dimethylamine functional groups. DOWEX MARATHON WBA-2 is specifically designed to give high throughput and economical operation in both water and non-water applications. It is particularly effective when used at flow rates of 25 bed volumes/hour (3 gpm/ft3) or less, providing high capacity of up to 1.25 eq/l (30 kgr/ft3) or more. In addition, its high physical strength and small bead size make it more resistant to bead breakage. Weak base anion resins are used in demineralizer systems for two reasons: 1. They have a higher total exchange capacity and regenerate more efficiently than strong base anion resins. This makes weak base resins more economical to operate on waters containing significant levels of chloride and sulfate. 2. They have better elution of naturally occurring organic species relative to strong base resins. The high reversibility to organics, aided by the absence of large beads, leads to a good resistance to fouling with adequate caustic ( 80 g/l or 5 lbs/ft3) and gives protection to the strong base anion resin typically used downstream. DOWEX MARATHON WBA-2 may be used in a simple two stage plant giving good quality water but without removal of silica or carbon dioxide. For full demineralization, the resin may be used in combination with a strong base anion resin such as DOWEX MARATHON A in a separate vessel, or combined with DOWEX MARATHON A LB in a single vessel as a layered bed. The tailored bead sizes of DOWEX MARATHON WBA-2 and DOWEX MARATHON A LB result in an excellent separation of the two resins. With such a combination of weak and str