MASTER TEST METHODS
MTM 0265: CATION SALT SPLITTING CAPACITY AND
PERCENT REGENERATION : H form resins
Objective
To determine the total exchange capacity of cation exchange resins on a weight (eq/kg) and volume (eq/L) basis. Also determine the percent regeneration.
Area of Application
This procedure is applicable to strong acid cation resins with sulfonic acid functional groups in the hydrogen form.
Principle
A sample of resin is pretreated as for the Moisture Holding Capacity. A known weight and volume of resin is eluted with NaNO3 and the quantity of H determined by titration with NaOH. This provides the initial quantity of H present. The resin is then fully converted to the H form, the H is eluted with NaNO3, and the quantity of H is determined by titration with NaOH. This provides the strong acid, or salt splitting, capacity. This capacity is assumed equivalent to the total capacity for cation resins with sulphonic acid functional groups.
Equipment
Dewatering apparatus.
Source of vacuum, 40 ± 2 torr below atmospheric pressure.
Analytical balance, ± 0.001 g precision or better.
Ventilated oven, 105 ± 2 °C.
Desiccator.
Tared weighing dishes.
25 ml graduated cylinder, Kimble 20022-25 or equivalent.
Fritted glass filter tube.
1 L volumetric flask.
100 ml pipet.
Equipment for NaOH titration.
Reagents
1.0 N HCl.
0.5 N NaNO3.
0.1000 N NaOH, standardized.
Deionized water.
Phenolphthalein indicator solution (5 g/L), used only for manual titrations.
Master Test Method
1. Prepare resin by the Master Test Method procedure for MHC.
2. Measure and record the MHC (to nearest 0.1%).