MEASUREMENT AND INTERPRETATION OF ZEOLITE NAA BUILDER PERFORMANCE

Ion exchange isotherms are commonly used to describe the distribution of ions between a solid and liquid phase under equilibrium conditions. In the detergent industry, the Ca-Na-zeolite A isotherm can be utiliz ed to determine the builder performance of zeolite NaA under a specifi c set of experimental conditions. In this paper, we demonstrate how th e Ca-Na-zeolite A isotherm is developed and utilized in measuring and interpreting the calcium exchange capacity score of zeolite NaA. Owing to the large number of testing parameters that affect the equilibrium distribution of calcium between the zeolite and solution phases, and hence the calcium exchange capacity score of the zeolite, a recommenda tion is made as to a standard set of test conditions that provide for both analytical precision and convenience. With this approach, builder performance differences between any two zeolites can then easily be m easured and assessed. As an extension to the isotherm principles devel oped in this paper, the prediction of zeolite performance in real dete rgent systems is illustrated. Particular attention is given to the mor e efficient utilization of the ion exchange capacity of zeolite NaA by the recently developed concentrated detergent systems.