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Effect of temperature and hydroxy aluminum interlayers on the adsorption of trace radioactive cesium by sediments near water‐cooled nuclear reactors
Author(s) -
Elprince A. M.,
Rich C. I.,
Martens D. C.
Publication year - 1977
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr013i002p00375
Subject(s) - adsorption , caesium , ion exchange , clay minerals , partition coefficient , aluminium , chemistry , ion , mineralogy , inorganic chemistry , nuclear chemistry , materials science , metallurgy , chromatography , organic chemistry
The adsorption of 137 Cs by sediments from the Savannah River Plant follows a theoretically expected linear relationship between ln Kd * and l/ T where Kd * and T are the equilibrium distribution coefficient (Cs adsorbed, meg g −1 /Cs + in solution, meq ml −1 ) and the temperature in kelvins, respectively. The slope of these plots decreases after removal of hydroxy Al interlayers with citrate pretreatment. Hydroxy Al interlayers thus make Cs + adsorption more temperature dependent. This thermal effect of hydroxy Al interlayers becomes more significant in sediments containing a nonswelling 2:1–2:2 intergrade clay mineral than in those containing a swelling 2:1–2:2 intergrade clay mineral. The phenomenon is explained by considering hydroxy Al interlayers as a source of hydronium ions H 3 O + which compete with Cs + for exchange positions in wedge zones. An increase in temperature favors an increase in H 3 O + ions, which in turn favors less adsorption of Cs + . Aside from their thermal effect the positively charged hydroxy aluminum polymeric groups drastically decrease the cation exchange capacity and consequently the adsorption of cesium.