Replaceability of Ammonium in Vermiculite with Acid Solutions1
- A. D. Scott,
- J. J. Hanway and
- A. P. Edwards2
NH4-saturated samples of Montana vermiculite were extracted with 1N Na, 1N K, and 0.1N acid solutions that varied in pH. In some cases, successive and continuous extractions with boiling solutions were used. In others, the vermiculite samples were leached or distilled with solutions at room temperature.
More NH4 was removed by the Na solutions as the pH of the extracting solution increased or decreased from neutrality. When the accumulation of replaced NH4 in the extracting solution was reduced by using alkaline solutions or by using the successive extraction method with the acid solutions there was an increase in the amount of NH4 removed. In a given extraction period the amount of NH4 removed by acid Na solutions increased linearily as the solution pH decreased.
More NH4 was removed by the K solutions as the pH of the extracting solution decreased. In the presence of a high concentration of a nonvolatile fixable cation (K) the alkaline solutions removed the least amount of NH4.
There was little effect of pH on the amount of NH4 removed by 0.1N acid solutions when the solution pH was above 3. When the pH of the acid solutions was decreased below 3, there was a rapid increase in the amount of NH4 removed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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