No abstract

Sorption characteristics of Cs+ and Sr++on montmorillonite and kaolinite type clays and soil fractions from various regions of Turkey were studied using the batch method. 137Cs and 90Sr were used as tracers. Concentrations of Cs+ and Sr++ ions ranged from 10-8to 10-2 mol/1; natural groundwater was used and the grain size of the solid particles was < 20 yμm. Equilibrium was reached in 4 - 7 days for Cs+and 7 - 11 days for Sr++. The distribution coefficient, RD, increased with decreasing grain size, suggesting mainly a surface phenomenon. The sorption isotherms were non-linear suggesting at least two different sorption processes. The sorption was found to be predominantly reversible. Cs+ was sorbed much stronger than Sr++in all samples. © 1988, Walter de Gruyter. All rights reserved

A comprehensive study has been carried out of the yield pattern of fission products formed in thermal neutron-induced fission of 235 U. An isotope separator on-line a nuclear reactor was used for rapid separation of the fission products. At a target temperature of 2400 Q C all fission elements, with the exception of the little volatile transition elements zirconium, niobium, molybdenum, technetium, ruthenium, and rhodium, are released. Their isotopes are then available for study which means that a very complete mapping of the yield distribution is within reach. In the analysis the delay between production and measurement and the overall separator efficiency for three consecutive elements -the one under study and its parent and grandparentare taken into account. Independent and/or cumulative yields have been obtained for 195 nuclear species, among them 83 isomeric states.

Batch experiments were performed to study the sorption behaviour of Ba2+ ion on three different clay minerals determined to be predominantly kaolinite, montmorillonite and mixed chlorite-illite. Synthetic groundwater was used and the concentration of Ba2+ ion was in the range of 10-8 to 10-4 N. Grain sizes of the solid particles were all <38 μm. Cation exchange capacities were obtained using the silver-thiourea (AgTU) method. The variation of RD values was studied as a function of contact time, shaking rate, Ba2+ ion concentration, v/m ratio and pH. The saturation time varied with each type of clay; about 6, 8 and 12 days of shaking time were necessary for chlorite-illite mixed clay, kaolinite and montmorillonite respectively. Shaking rate affected only the rate of sorption and not the saturaton RD values. Sorption was found to be reversible on kaolinite and partly reversible on montmorillonite and chlorite-illite clays. The variation of RD as a function of Ba2+ ion concentration exhibited characteristic inverse S-shaped curves suggesting the presence of at least two different types of exchange sites. Sorption of Ba2+ ion was observed to depend on pH and v/m ratio. The sorption isotherms were found to fit Freundlich and Dubinin-Radushkevich type isotherms well. © 1990

The sorptlon desorptlon behavlour of Cs ion in the concentration region of 10-8 to 10-4 meqml-I have been studied using clay and soil fractions from various regions of Turkey. The sorption curves for all the material studied show similar behaviour indicating at least two different sorption processes. One with high and the other with low distribution coefficients. The results of desorption studies indicate that Cs cation is to a large extent attached to the solid material in a reversible manner. The adsorption isotherms were found to be nonlinear in all cases. The increase of R D values with decreasing particle size in most cases, suggests that sorption and or exchange is primarily a surface phenomenon in the clay and soil fractions studied.