SOME FACTORS AFFECTING THE INTERACTIONS OF ORGANOPHILIC CLAY-MINERALS WITH RADIOIODINE

Sorption and desorption of radioiodine (I-125(-)) were measured with different particle size fractions (mostly clay) of Cretaceous clay and vermiculite treated with hexadecylpyridinium (HDPY+). Furthermore, the interactions of I-125(-), Cs-134(+) and Ca-45(2+) with differently saturated HDPY-clays were studied using the batch method. Highest iodide sorption (R(D) approximate to 12000 ml.g(-1)) was observed in the medium size (0.2-0.6 mu m) clay fractions. The iodide sorption was found not to be directly correlated to the alkylammonium ion incorporation into the samples of the different grain size fractions. A good correlation between HDPY+ supply and I-125(-) distribution ratios has been observed in non-fractionated clay samples. Tests with partially saturated HDPY-vermiculite revealed simultaneous sorption of both, cationic (Cs-134(+), Ca-45(2+)) and anionic (I-125(-)) radionuclides.