Cesium exchange capacity

AMP-1 4.0 Microcrystalline ammonium molybdo-phosphate with cation exchange capacity of 1.2 mequiv/g. Selectively adsorbs larger alkali metal ions from smaller alkali metal ions, particularly cesium. 

Lim CH, Jackson ML, Koons RD, Helmke PA (1980) Kaolins Sources of differences in cation exchange capacity and cesium retention. Qays Clay Miner 28 223-229 Low PE (1981) The swelling of clay III Dissociation of exchangeable cation. Soil Sci Soc Amer J 45 1074-1078... 

For both cesium and barium sorption, there is reasonable agreement between the total concentrations of desorbed species and the ion-exchange capacities determined by isotopic redistribution. The small differences which exist could easily be due to the precision in the elemental analyses. (Also, the experimental technique would not have detected desorption of hydrogen ions.) The solid-phase concentrations of sodium, potassium, magnesium, calcium. 

Differences in Cation-Exchange Capacities and Cesium Retention, Clays Clay Min. 28, 223-229. 

C. H. Lim, M. L. Jackson, R. D. Koons, and P. A. Helmke, Kaolins Sources of differences in cation-exchange capacities and cesium retention. Clays and Clay Minerals 28 223 (1980). 

Silica is the base for an ammonium molybdophosphate exchanger which can be used for recovering cesium ions from acid solution (548, 549). Kaletka and Konecny also use silica gel as a support for insoluble nickel, copper, cadmium, or zinc hexa-cyanoferrates, which act as cation exchangers. They can remove traces of cesium ions even from strong nitric acid solution. Exchange capacities of the diflerent compounds were measured (550). ... 

Operation of the cesium catalyst at a much lower inlet temperature than the potassium-promoted catalyst achieved a sulfur dioxide conversion in the range 99.2-99.6%. This was comparable to a double-absorption plant but with a lower capital cost apart from increased heat exchange capacity and a slightly more expensive catalyst. It allows producers to use existing four-bed single-absorption units and meet environmental demands without the capital expense of a new plant. 

Example Shaking 50 mL of 0.001 Af cesium salt solution with 1.0 g of a strong cation exchanger in the H-form (with a capacity of 3.0 mequiv g ) removes the following amount of cesium. The... 

Therefore, based on available literature, the following sorption results were expected (l) as a result of the smectite minerals, the sorption capacity of the red clay would be primarily due to ion exchange associated with the smectites and would be on the order of 0.8 to I.5 mi Hi equivalents per gram (2) also as a result of the smectite minerals, the distribution coefficients for nuclides such as cesium, strontium, barium, and cerium would be between 10 and 100 ml/gm for solution-phase concentrations on the order of 10"3 mg-atom/ml (3) as a result of the hydrous oxides, the distribution coefficients for nuclides such as strontium, barium, and some transition metals would be on the order of 10 ml/gm or greater for solution-phase concentrations on the order of 10 7 mg-atom/ml and less (U) also as a result of the hydrous oxides, the solution-phase pH would strongly influence the distribution coefficients for most nuclides except the alkali metals (5) as a result of both smectites and hydrous oxides being present, the sorption equilibrium data would probably reflect the influence of multiple sorption mechanisms. As discussed below, the experimental results were indeed similar to those which were expected. 

If those sorption capacities were due to ion exchange, it would be expected that preparation of the cesium- and barium-saturated clays would have caused various counter ions such as those of sodium, potassium, magnesium, and calcium to be desorbed from the clay and to appear in. the 1.0 M solutions. The total... 

For each nuclide studied, the sorption distribution coefficients appeared to result from a minimum of two separate mechanisms. In all cases, one mechanism appears to be an ion-exchange phenomena associated with the silicate phases and appears to have a relatively much larger sorption capacity than the other mechanism. In the case of cesium (and probably rubidium) the second mechanism appears to also be related to the silicate phases and may or may not be an ion-exchange phenomena. However, for the other elements studied, the second mechanism appears to be related to the hydrous iron and manganese oxides and again may or may not be an ion-exchange process. 

For example, the equilibrium distribution of cesium and rubidium between sulfophenolic cation exchanger KU-I and neutral solution is characterized by the value ag = 1.5-1.6 while in alkaline solution = 1.8-2.0. In the latter case sorption capacity is 2.5-3.0 times as great as it is in neutral solution [34]. 

The recovery and purification of cesium-137 from Purex acid waste using a synthetic zeolite has been studied. Zeolite capacity and selectivity for cesium were determined. Stability of the synthetic zeolite to high radiation fields and chemical attack was adequately demonstrated. Kilocurie quantities of cesium-137 of 98+% chemical purity were prepared using zeolite ion exchange. 

Figure 2. Variations in cesium capacity with exchanger lot and loading cycle...

Potassium, sodium, calcium and other positively charged ions present in the channel are exchangeable and get replaced by heavy metal ions. Heavy metals present in wastewater (chromium, mercury, lead and cadmium) are effectively adsorbed on zeolites. Clinoptilolite is a widely used zeolite for wastewater treatment due to its higher selectivity and ion exchange capability to remove heavy metal ions including strontium and cesium (Grant et al. 1987). Vaca Mier et al. (2001) studied the selectivity of zeolite for the removal of various heavy metals and observed that zeolites show higher selectivity for lead ions followed by cadmium, copper and cobalt. Table 2.2 (Bailey et al. 1999) shows the some of the reported adsorption capacities of zeolites. 

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