Adsorption characteristics of a clinoptilolite-rich zeolite compound for Sr and Cs

Johannes H. Sterba,Jan M. Welch,Florian Wallenko,Hannes Sperrer

doi:10.1007/s10967-018-6096-6

Johannes H. Sterba, Jan M. Welch + Show 2 more

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https://doi.org/10.1007/s10967-018-6096-6

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Abstract

The Sr and Cs adsorption capacities of LithoFill™, LithoGran™ and a competing clinoptilolite containing zeolite product were investigated by radioanalytical methods (85Sr and 134Cs gamma spectroscopy). The dependence of adsorption and adsorption rate on physical factors including temperature, available ions and time were assessed. In addition, the reversibility of adsorption under high ionic strength conditions was also examined. In general, cesium is more strongly adsorbed than strontium, adsorption yields are generally independent of temperature (from room temperature to 65 °C) and adsorption is relatively rapid (identical results for 2 or 5 day adsorption times). As expected, increasing the concentration of other ions in solution tends to reduce adsorption of cesium and strontium. In general, Cs adsorption ranges between 54.5 and 45.2 mg/g for LitoFill and LitoGran samples and between 36.9 and 24.4 mg/g for the competing product. For Sr adsorption, ranges are 30–21 mg/g and 7.3–6.7 mg/g respectively, leading to the conclusion that the higher content of clinoptilolite in the LitoFill/LitoGran samples results in better adsorption characteristics.

Highlights

ExperimentalZeolites, in the form of clinoptilolite ((Na,K,Ca)2-3Al3(Al,Si)2Si13O36Á12(H2O)) are well known as natural inorganic ion-exchangers [1–5] with applications in geochemical [6–8], agricultural [9] and decontamination/waste disposal [10–19] operations
The Sr and Cs adsorption capacities of LithoFillTM, LithoGranTM and a competing clinoptilolite containing zeolite product were investigated by radioanalytical methods (85Sr and 134Cs gamma spectroscopy)
Cesium is more strongly adsorbed than strontium, adsorption yields are generally independent of temperature and adsorption is relatively rapid

Summary

Introduction

ExperimentalZeolites, in the form of clinoptilolite ((Na,K,Ca)2-3Al3(Al,Si)2Si13O36Á12(H2O)) are well known as natural inorganic ion-exchangers [1–5] with applications in geochemical [6–8], agricultural [9] and decontamination/waste disposal [10–19] operations. As expected, increasing the concentration of other ions in solution tends to reduce adsorption of cesium and strontium. For Sr adsorption, ranges are 30–21 mg/g and 7.3–6.7 mg/g respectively, leading to the conclusion that the higher content of clinoptilolite in the LitoFill/LitoGran samples results in better adsorption characteristics.

Results

Conclusion