Adsorption of uranyl ion on modified alumosilicate minerals
2006
Matijasevic, S.,Institut za tehnologiju nuklearnih i drugih mineralnih sirovina, Beograd (Serbia) | Dakovic, A.,Institut za tehnologiju nuklearnih i drugih mineralnih sirovina, Beograd (Serbia) | Stojanovic, M.,Institut za tehnologiju nuklearnih i drugih mineralnih sirovina, Beograd (Serbia)
In this chapter, the investigation results of adsorption of uranyl ion on different modifications of zeolitic mineral clinoptilolite are presented. Adsorption was investigated at different amounts of solid phase in suspension, different concentrations of uranyl ion in solution, as well as at different pH values. The modified clinoptilolite samples were obtained by treatment of clinoptilolite with acid: hydrochloric as well as with modification of mineral with surface active organic substances: primary ammine (octadecyl ammine) and quaternary ammonium ions (octadecyldimethylbenzyl ammonium ions and hexadecylthreemethyl ammonium ions). Starting and modified clinoptilolites were characterized by chemical analysis, XRPD analysis, thermal (DTA/TGA) analysis, IR spectroscopy, and by determination of cation exchange capacity, while starting and nonadsorbed amounts of uranyl ion were determined by fluorometric method. Uranyl ion adsorption experiments on natural unmodified zeolitic mineral showed that uranyl ion adsorption was low (adsorption index 35%), and that treatment of clinoptilolite with acids as well as with surface active substance significantly increased the adsorption of uranyl ion. For organozeolites, it was determined that the highest adsorption of uranyl ion was achieved on organozeolite in which all inorganic cations at zeolitic surface were replaced with organic cations. Kinetics of adsorption showed that adsorption of uranyl ion begins very fast and that the most of uranyl ion was adsorbed in the first 30 minutes. Practically, there were no changes in uranyl ion adsorption within next 72 hours.
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