Phosphate adsorption in allophanic soils

A - Papers appearing in refereed journals

Imai, H., Goulding, K. W. T. and Talibudeen, O. 1981. Phosphate adsorption in allophanic soils. Journal of Soil Science. 32 (4), pp. 555-570.

AuthorsImai, H., Goulding, K. W. T. and Talibudeen, O.
Abstract

The kinetics and heats of phosphate adsorption were measured on the <2 μm Na‐saturated fractions of three allophanc‐rich soils from Japan. Between 50 and 2250 μmol P g−1 as sodium phosphate were added to the soil fractions at pH 5 and pH 7, and at initial concentrations of 5 and 25 × 10−4m to avoid aluminium phosphate precipitation.

An initial ‘instantaneous’ adsorption associated with exposed sites and, simultaneously, two inverse exponential rates of adsorption on internal and freshly forming external sites were observed. These rates are attributed to changes in the microstructure of allophane and to the desorption of organic matter held on allophanic surfaces. This interpretation is strongly supported by corresponding changes in the heats of adsorption with time. Calorimetry clearly indicates that when very large amounts of phosphate are added, new and very reactive surfaces are progressively exposed.

More phosphate was adsorbed when the soil was acid and when the soil contained less organic matter.

KeywordsSoil Science
Year of Publication1981
JournalJournal of Soil Science
Journal citation32 (4), pp. 555-570
Digital Object Identifier (DOI)doi:10.1111/j.1365-2389.1981.tb01729.x
Open accessPublished as non-open access
Output statusPublished
Publication dates
Online28 Jul 2006
Print01 Dec 1981
Copyright licensePublisher copyright
PublisherWiley
ISSN0022-4588

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