R. E. Karamanos1, D. A. Rennie1
1Department of Soil Science, (Jniversity of Saskatchewan, Saskatoon, Sask. S7N 0W0.
Tóm tắt
Nitrogen isotopic fractionation during ammonium adsorption by clay colloids was shown to occur in two time-dependent stages. A rapid 15N enrichment of the NH4+ in solution was followed by a gradual depletion until, after an 8- to 10-h equilibrium period, the δa15N of the NH4+ in solution was approximately 1; this value was significantly lower than the initial value of 2.3 for the NH4Cl used in these experiments. The isotopic equilibrium constant (ke) for the ammonium adsorption reaction was greater than unity, and higher for the Ca2+- than K+-saturated clay colloids.
