Sorption of Gaseous Ammonia by Clay Minerals as Influenced by Sorbed Aqueous Vapor and Exchangeable Cations1
- James M. Brown and
- W. V. Bartholomew2
Ammonia sorption by homoionic clay systems containing small amounts of adsorbed aqueous vapor was investigated by manometric techniques employing equilibrium measurements in a special sorption apparatus.
Sorption isotherms from this investigation indicated that there is considerable interaction between ammonia sorption and moisture levels of the clays. At ammonia pressures below 60 to 100 mm. Hg, “dry” bentonite and halloysite sorbed more ammonia than comparable moist clays. At higher ammonia pressures, moist clays sorbed more ammonia than “dry” clays with the greatest amount of sorption occurring at the higher moisture levels.
There was evidence of competition between aqueous vapor and ammonia for sorption sites on the clays. The kind of cation on the exchange complex also exerted an influence on ammonia sorption by moist clay, the mechanism of influence probably arising in part through alteration of the quantity and nature of the water of hydration.
The same order of influence of exchangeable cations on ammonia sorption occurred with the moist clays as was previously reported for dry clays, i.e., Al-clay > Ca-clay > K-clay.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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