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

This Article Full Text (PDF) An erratum has been published 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 Lahav, N. Articles by Hochberg, M. Search for Related Content PubMed Articles by Lahav, N. Articles by Hochberg, M. Agricola Articles by Lahav, N. Articles by Hochberg, M.

Kinetics of Fixation of Iron and Zinc Applied as FeEDTA, FeHDDHA and ZnEDTA in the Soil¹

ABSTRACT

The disappearance of zinc and iron from soil solution after their addition as soluble metal chelates is attributed to adsorption and fixation. The value of the adsorption coefficient, K_d, was estimated from a batch experiment but because of the inaccuracy involved they were evaluated from the breakthrough curves of column experiments using Rehovot sand. FeEDDHA was neither adsorbed nor was its iron fixed by the soil to any significant extent.

The fixation of iron applied as FeEDTA was found to be a first order reaction. Assuming that the fixation reaction kinetics is similar in both the solution and the solid phase, then the reaction rate constant can be expressed as k = (k₁ + k₂K_d)/( + K_d), where k₁ and k₂ are the reaction rate constants in the liquid and solid phases, respectively. is the volumetric water content and is the bulk density. By using 5 different soil/water ratios, the values of k₁ and k₂ were found to be 0.0096 h^-1 and 0.087 h^-1, respectively. The value of k was also estimated from the breakthrough curve in a column experiment by using the relative effluent concentration under steady state condition (C/C_o)_s.

The adsorption of ZnEDTA was negligible under the present experimental conditions. Thus k = k₁ and is independent of the water content and bulk density. This was shown by comparing the results of the two experimental techniques. The value of k₁ thus found was 0.084 h^-1. The first order model of the fixation reaction of zinc applied as ZnEDTA is applicable for time periods up to 8 to 10 hours.

¹ Contribution from the Dep. of Soil and Water, The Faculty of Agriculture, Rehovot; The Hebrew Univ. of Jerusalem, Israel.

² Associate Professor and Graduate Student, respectively.

Received for publication September 27, 1974. Accepted for publication October 10, 1974.