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Sorption of Cesium by Soils and Its Displacement by Salt Solutions
Author(s) -
Coleman N. T.,
Lewis R. J.,
Craig Doris
Publication year - 1963
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1963.03615995002700030023x
Subject(s) - vermiculite , montmorillonite , sorption , chemistry , ion exchange , leaching (pedology) , inorganic chemistry , potassium , illite , kaolinite , caesium , divalent , clay minerals , ion , salt (chemistry) , soil water , mineralogy , adsorption , geology , organic chemistry , paleontology , soil science
Cesium was sorbed by montmorillonite, illite, and kaolinite in quantities corresponding to exchange saturation and was displaced readily on leaching with 1 N KCl or CaCl 2 . Vermiculite and heated (600°C., 12 hours.) K‐montmorillonite bound Cs tightly against displacement by CaCl 2 and AlCl 3 , but not by KCl or NH 4 Cl. Prolonged leaching with 1 N KCl removed 97.5% of the Cs sorbed by heated K‐montmorillonite, while 1 N CaCl 2 eventually displaced 88%. Potassium and Rb sorbed on vermiculite were displaced more rapidly by Ca or Mg than by monovalent ions, but this was not the case with heated K‐montmorillonite. The exchange‐displacement behavior of Cs on vermiculite and heated K‐montmorillonite suggests that this ion is unique in that its sorption in interlayer spaces leads to interplanar distances which admit K and NH 4 ions but greatly restrict the entry of Ca. Cesium, then, is not expected to follow the “fixation‐release” rules that have been developed for K and NH 4 . Heated montmorillonite samples leached with mixtures of CsCl and other salts sorbed more Cs when the complementary ion was Ca or Al than when it was K or NH 4 . Differences were especially pronounced at low equivalent fractions of Cs in the leaching solution, showing a larger preference by exchange sites for Cs over divalent than over monovalent ions. Apparent “specific sorption” of Cs against exchange with CaCl 2 occurred at quite large Cs saturations.