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REACTIONS OF AMMONIA WITH SOIL, III SORPTION OF AQUEOUS NH 3 BY HOMOIONIC SOIL CLAYS
Author(s) -
ASHWORTH J.,
PYMAN M. A. F.
Publication year - 1979
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1979.tb00961.x
Subject(s) - sorption , chemistry , aqueous solution , inorganic chemistry , ammonia , ion exchange , soil water , clay minerals , titration , nuclear chemistry , adsorption , ion , mineralogy , geology , organic chemistry , soil science
Summary Homoionic clay suspensions were equilibrated at 25°C with aqueous NH, (0.01 to 0.30 M) by agitating for several days. Using clays extracted from three different soils, sorption of NH 3 , measured by titration, followed the order Na > Ca > NH 4 ‐clay. The difference in NH 3 sorption between Na‐clay and NH 4 ‐clay was matched by an increase in Na + ion concentration in the aqueous phase of suspensions of Na‐clay treated with NH 3 , but there was no such effect with Ca‐clay. Sorption of NH 3 on NH 4 ‐clay in aqueous suspension is considered due to proton donation at sites of pH‐dependent charge, and the additional sorption on Na‐clay to displacement of Na + by NH 4 + ions. The additional sorption on Ca‐clay seems largely due to co‐ordination of Ca 2+ ions with molecular NH. Exchangeable cations affect NH 3 sorption differently when an aqueous phase is present than when dried homoionic materials are treated with NH 3 gas.