Title

The Estimation of Free Aluminium and the Competition Between Fluoride and Humate Anions for Aluminium

Author Info

G. S.P. Ritchie, University of Western AustraliaFollow
M. P. Nelson, University of Western Australia
M. G. Whitten, University of Western Australia

Recommended Citation

Postprint version. Published in Communications in Soil Science and Plant Analysis, Volume 19, Issue 7-12, May 1, 1988, pages 857-871.

NOTE: At the time of publication, the author G.S.P. Ritchie was not yet affiliated with Cal Poly.

The definitive version is available at https://doi.org/10.1080/00103628809367980.

Abstract

Three equations for estimating the concentration of free aluminium, [Al³⁺], from the activity of free fluoride, (F^-), were compared to assess their suitability for estimating [Al³⁺] in acid soil solutions and in competition studies. We then studied the ability of humic acids to compete with F for Al by comparing the behaviour of the humic acids in the presence of F and Al with that of several carboxylic acids under the same conditions. All three methods of estimating [Al ] were limited in their applicability to acid soil solutions but were uitable for estimating [Al³⁺] in competition studies when equimolar quantities of Al_T and F_T were used. Humic acids extracted by NaOH and by Na₂H₂P₂O₇ decreased the amount of Al complexed with F by 21 -100% at pH 4 and 6 and ratios of Cmoles of humic acid: F>l. The Al humate complex precipitated when the Al: humic acid ratio was >1. Both humic acids appeared to be more effective than simple carboxylic acids at competing with F for Al.

Disciplines

Food Science | Nutrition

Copyright

1988 Taylor & Francis. This is an electronic version of an article published in Communications in Soil Science and Plant Analysis.