HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ishiguro, M. Search for Related Content PubMed Articles by Ishiguro, M. Agricola Articles by Ishiguro, M.

Ion Transport in Soil with Ion Exchange Reaction: Effect of Distribution Ratio

The National Research Institute of Agricultural Engineering, 2-1-2, Kannondai, Tsukuba, Ibaraki, 305, Japan

*Corresponding author.

ABSTRACT

Exchanging ionic-solute transport through soil columns is significantly affected by ion exchange reaction. The breakthrough curve (BTC) for the input ion based on time or pore volume shifts to the right as the ion-exchange capacity increases or the input ion concentration decreases. The shapes of the BTCs with different mean breakthrough times are easily compared when the BTCs are normalized by the mean breakthrough times. The influence of the distribution ratio, D_g, the ratio of the amount of ions adsorbed in the soil to that in the solution in a unit volume of the soil, on normalized BTCs with nonlinear exchange isotherms was evaluated. The cases studied here involved ion exchange in a binary system at a constant total concentration under steady-state water-flux conditions. The BTCs were calculated and interpreted using a normalized, one-dimensional advective-dispersive equation. It was determined that the effect of the nonlinear isotherm on the BTC increases as D_g increases. It was also shown that, when D_g is much greater than unity, an increase in D_g has no effect on the BTC. These results were confirmed with experimental data on actual soil columns of an allophanic Andisol. When the BTCs had a similar nonlinear exchange isotherm and Péclet number, the deviations among them were easily interpreted by the D_g values.

Contribution of the National Research Institute of Agricultural Engineering, Japan.

Received for publication October 23, 1991.