Structural Implications in Cesium Sorption

Reversibility of radiocaesium sorption on illite

“…Sorption of trace amounts of radiocaesium on illitic-type clay minerals in the natural environment has often been described as largely "irreversible," as most of the radiocaesium becomes fixed in the interlayers between the platelets of the minerals (Page and Baver, 1939;Jacobs and Tamura, 1960;Tamura and Jacobs, 1960;Sawhney, 1964;Comans and Hockley, 1992), minimising the transfer of radiocaesium into the ecosystem. However, observations on radiocaesium partitioning in anoxic freshwater sediments (Evans et al, 1983;Comans et al, 1989;Comans, 1999;De Koning et al, 2000) and the persistence of radiocaesium in water, fish, and plants after the Chernobyl accident (Jonsson et al, 1999;Smith et al, 1999;Smith et al, 2000), indicate that radiocaesium sorption must remain at least partly reversible.…”

State of the Art Report on High-Level Waste Tank Closure

“…Illite has been known as a selective sorbent for cesium for decades [Tamura, 1961;Tamura, 1963;Tamura and Jacobs, 1960;Cowser, et al, 1966;Kaplan, et al, 1999]. Illite has a relatively low equivalent exchange capacity, but the interlayer spacing between silicate sheets in the crystalline is well matched to the cesium ion diameter.…”

“…The chemistry and composition of Portland cement are discussed in great detail elsewhere [Conner, 1990;IAEA, 1993;Lea, 1970;Soroka, 1979;Bye, 1983;Ghosh, 1983;Taylor, 1990]. The main points of interest for cement stabilization/solidification are: 1) the alkaline (high pH) environment of the cement matrix, 2) the formation of calcium hydroxide as a normal cement hydration product, and 3) the relatively low hydraulic conductivity (permeability) of a cemented material relative to soil.…”

Adsorption behavior of radioactive cesium by non-mica minerals

“…Soil is composed of various components, including minerals, clay minerals, metal oxides/hydroxides, and organic materials. Cesium at a low concentration is strongly sorbed on micalike minerals of sediments [11][12][13]. Kozai et al have examined the Cs fallout on soils collected in Fukushima, Japan, and they found that not only mica-like minerals, but also minerals other than mica-like minerals (nonmica minerals) probably fixed the deposited radioactive Cs in the soil [14].…”