My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in SSSAJ

  1. Vol. 48 No. 1, p. 39-45
     
    Received: Mar 2, 1982
    Published: Jan, 1984


 View
 Download
 Alerts
 Permissions

doi:10.2136/sssaj1984.03615995004800010007x

Potassium-Calcium Exchange in a Multireactive Soil System: I. Kinetics1

  1. P. M. Jardine and
  2. D. L. Sparks2

Abstract

Abstract

The kinetics of K exchange were investigated in Ca-saturated samples from the Ap horizon of an Evesboro soil from Delaware. Biphasic kinetics characterized the first-order plots for K adsorption and desorption at 283 and 298K with the two simultaneous reactions being attributed to exchange sites with varying reactivity for K and Ca ions. The rapid reaction was ascribed to exchange sites of the soil that are readily accessible to cation exchange reactions, whereas the slow reaction was attributed to exchange sites that are difficultly accessible to cation exchange reactions. Confirmation of the hiphasic kinetics was achieved through the use of cetyltrimethylammonium bromide (CTAB). Parabolic diffusion plots for K adsorption and desorption at 283 and 298 K indicated that an intraparticle diffusion process may be rate limiting for the difficultly accessible sites of the soil. The initial deviation from linearity of the parabolic plots for K desorption suggested that film diffusion may be rate limiting for desorption on readily accessible sites of the soil that form strong bonds with Ca ions. At 313 K the initial rapid kinetics of exchange was no longer present, and the exchange process was described by a single first-order reaction. The parabolic plots at 313 K suggested that this phenomenon could possibly be attributed to the finite rate at which the polymer structure of soil organic matter changes in response to the adsorption and desorption of the two reacting cations.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America

Facebook   Twitter