Premium
Replaceability of Ammonium Fixed in Clay Minerals as Influenced by Ammonium or Potassium in the Extracting Solution
Author(s) -
Hanway J. J.,
Scott A. D.,
Stanford G.
Publication year - 1957
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/sssaj1957.03615995002100010008x
Subject(s) - vermiculite , chemistry , ammonium , salt (chemistry) , potassium , bentonite , ion , sodium , nuclear chemistry , inorganic chemistry , materials science , geology , organic chemistry , paleontology , composite material
Fixed NH 4 in vermiculite and bentonite was completely released by distillation in NaOH solutions. Small amounts of K in the solutions, however, blocked this release of NH 4 . If the amount of K was in excess of 2 K ions per 100 Na ions, no fixed NH 4 was released from vermiculite. With smaller amounts of K present, the amount of fixed NH 4 released decreased as the K/Na ratio in solution was increased. In an equilibrium NaCl extraction, small amounts of either fixable ion, NH 4 or K, in the solution prevented the release of fixed NH 4 . There was no blocking from the NH 4 in the NaOH distillations since it was lost from the alkaline systems. In the salt solutions, NH 4 was more effective than K in blocking the release of fixed NH 4 . The blocking effect of a gixen fixable/nonfixable ion ratio in the neutral salt solutions increased as the amount of salt extractant per gram of mineral was increased. This is due to the preferential adsorption of the fixable cations. Higher K/Na ratios were required to block the release of fixed NH 4 in neutral salt solutions than in alkaline solutions. Ten K ions per 100 Na ions in NaCl were not as effective as 2 K ions per 100 Na ions in NaOH. Higher K/Na or NH 4 /Na ratios were required to block the release of fixed NH 4 from bentonite than from vermiculite. The NH 4 /Na ratio required to completely prevent the release of fixed NH 4 from bentonite by NaCl was 0.04 as compared to 0.02 for vermiculite.