THE SORPTION CAPACITY OF MOSSES AND LICHENS OF ZAURALIE IN RELATION TO LEAD IONS

The purpose of the study is mosses and lichens of the Kurgan region for use as sorbents of heavy metals. The sorption of lead ions (II) is studied on the native and mechanochemically activated samples of true moss (Pleurozium schreberi), white moss (Sphagnum fuscum), lichen genus cladonia: cladoniaforest (Cladonia sylvatica) and cladonia horned (Cladonia cornuta), growing in the ecologically clean districts of Zauralie. The concentration of lead ions in model solutions has been measured ionometrically (ion-selective electrode – XC-Pb-001). The specific surface area of natural sorbents has been determined using the classical dynamic method of low-temperature adsorption of inert gases (Sorbi®-MS device). Sorption isotherms have been obtained. The sorption kinetics has been studied. Equilibration time varies from 30 to 45 min. It is shown that the maximum sorption of lead ions (is) on white moss (a=0.25 mmol/g). The mathematical treatment of sorption isotherms has been fulfilled, actual values of empirical constants of Freundlich’s and Langmuir’s equations and correlation coefficients have been calculated. Langmuir’s model is most suitable to describe the sorption processes. All the used sorbents are macroporous. The mechanochemical activation of moss and lichen with solid sodium hydrogen carbonate leads to an increase in the sorption of lead ions (II) by 2–3 times, which is an indirect confirmation of the ion-exchange mechanism of sorption.