The cesium ion adsorption by Turkish clays, i.e., bentonite, zeolite, sepiolite, and kaolinite, was investigated as a function of Cs 1 concentration, pH, time, and temperature using the Cs-137 radiotracer method. The analysis of some major and minor components of clays was performed with ED-XRF. Bentonite was shown to exhibit the highest capacity and sorption affinity toward Cs. The best fits for adsorption isotherms were with Freundlich and D-R models. The second order rate constant of cesium sorption was highest for kaolinite among the clays. Cesium adsorption proceeded essentially by ion exchange and partly by specific adsorption mechanisms. The results showed that especially bentonite and zeolite can be used as effective barrier materials for sorptive hindrance of an expanding Cs radioisotope plume.
ABSTRACT:The polymerization of acrylamide, initiated by a cerium (IV) [Ce(IV)] ammonium nitrate-methionine redox initiator system, was carried out in an aqueous solution at different reaction conditions. The dependence of molecular weight and polymerization yield on the concentration of Ce(IV), polymerization time, and temperature was determined. The molecular weight distributions (MWD) of the resulting polymers were examined using the HPLC method. Based on the HPLC results, optimum reaction conditions were determined that provided an opportunity to obtain a polymer that had a narrow MWD.
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