Potentiometric titration of natural clinoptilolites
Acid-base properties of zeolite tuffs of Cheboksary, Holin and Tedzamy deposits were studied by potentiomet-ric titration of their decationized forms with НС1 solution at concentration of background electrolyte 1 M and 0.1 M КС1. The acidity parameters of individual types of the clinoptilolite ion-exchange centers of have been calculated from the titration curves of the zeolites using the method of computer modelling of potentiometric titration data suggested earlier. The full ex­change capacities were determined by К<sup>+</sup> ion using static and dynamic methods. Potentiometric titration was carried out by the titration of the zeolites using one sample method. The clinoptilolites contain at least three types of the sorption centers. They differ in the acid strength expressed by the pK parameter and its dependence of the degree of neutralization Apk. The amount of strong acidic groups (pK<sub>1</sub> = 0.2) is 0.13-0.26 m-eq/g. The number of weak acid groups in the samples of clinoptilolites is different (pK<sub>2</sub> > 3 and pK<sub>3</sub> > 7).