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Rate of Cation Exchange on Clay Minerals as Determined by Specific‐Ion Electrode Techniques
Author(s) -
Malcolm R. L.,
Kennedy V. C.
Publication year - 1969
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/sssaj1969.03615995003300020024x
Subject(s) - ion exchange , kaolinite , clay minerals , montmorillonite , vermiculite , cation exchange capacity , illite , chemistry , potassium , inorganic chemistry , sodium , mineralogy , ion , analytical chemistry (journal) , materials science , geology , environmental chemistry , soil water , soil science , organic chemistry , composite material
A cationic electrode (used as a potassium specific‐ion electrode and a sodium specific‐ion electrode were used to measure rates of cation exchange on clay minerals. The Ba‐K exchange rates for kaolinite, illite, and montmorillonite were rapid with >75% exchange being measured within 3 sec. Because this time interval represents response time of the specific‐ion electrode, the Ba‐K exchange on these clay minerals occurs at a faster rate than this and may be an instantaneous process. Ba‐K exchange on vermiculitic materials was characterized by both a rapid and a slow rate of exchange. A major part of the Ba‐K exchange in silt‐ and clay‐size vermiculite was found to be diffusion controlled. Ca‐K, Mg‐K, Ca‐Na, and Mg‐Na exchange rates were rapid for all vermiculites and other clay minerals used in the experiment. Only Poole vermiculite exhibited two rates of Ba‐Na exchange similar to those shown by all vermiculites during Ba‐K exchange. Ba‐Na exchange rates on all vermiculites except Poole were rapid.