About weak acid polishers
A weak acid cation exchange unit filled with ResinTech WACMP can be used as a polisher unit following a two bed cation and anion exchange train. From a typical operating cation and anion demineralizer train, the leakage from the anion unit will exist as sodium hydroxide or NaOH. This will tend to elevate the pH of the demineralizer effluent. To further remove the sodium and at the same time lower the pH to a more neutral number, a weak acid cation operating in the hydrogen cycle is used in the final position.
The weak acid cation unit should be designed with a 24 inch minimum bed depth, and be regenerated with 15 pounds per cubic feet of sulfuric acid (the waste acid from the strong acid cation exchange unit can be used for regeneration). The capacities realized with this unit range from between 10 to 20 kilograins per cubic foot when the operation is taken to an end point of 1%. The higher capacity of 20 kilograins per cubic foot will occur when the unit is operated at a kinetic flow rate of 2 gpm per cubic foot; 10 kilograins per cubic foot can be expected when the unit is operated at the higher kinetic flow rate of 4 gpm per cubic foot. Effluent quality will be 1 megohm at a minimum.