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Potassium Fixation by Amorphous Aluminosilica Gels
Author(s) -
Reeuwijk L. P.,
Villiers J. M.
Publication year - 1968
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/sssaj1968.03615995003200020023x
Subject(s) - chemistry , potassium , alkali metal , saturation (graph theory) , cation exchange capacity , amorphous solid , ion exchange , inorganic chemistry , mineralogy , ion , crystallography , organic chemistry , geology , mathematics , combinatorics , soil science , soil water
Synthetic aluminosilica gels fixed potassium in varying amounts against replacement by common alkali and alkaline earth cations; the larger the solvated size of the replacing cation the greater was the amount of K retained. Replacing power thus followed the lyotropic series NH 4 > Na > Ba > Ca > Mg. The amounts of K fixed against exchange by a particular ion increased with total cation‐exchange capacity (in turn dependent on gel composition) and with the pH value at which K‐saturation originally took place. A marked increase in capacity to fix K was shown to result from drying the gels prior to K‐saturation. Drying presumably increased the rigidity of channels in the gel structure which restrict the passage of larger hydrated cations and which, as with zeolites, are responsible for the fixation phenomenon. For xerogels, wet‐ and dry‐fixation measurements yielded results of the same order of magnitude.