Molybdenum retention by Kenyan soils
Abstract
Studies on the adsorption of molybdenum on sixteen Kenyan soils representing
seven soil orders showed that the adsorption was strongly dependent on the amount of
crystalline iron in the soil and on the pH measured in water of the soil. The maximum
amount of adsorption of molybdenum occurred at about the pI(. of molybdic acid.
The studies also showed that the adsorption conformed to the Langmuir adsorption
isotherm, with only two exceptions. There were also significant correlations between the
calculated adsorption maximum and the percentage organic carbon content, DCBextractable
iron, oxalate-extractable iron, DCB-extractable aluminum, DCB-extractable
manganese and the specific surface of the soil.
A surface complexation model, the constant capacitance model, was used to model
the adsoption data. The model predicted the right order of magnitude of the maximum
adsorption for these soils. However, it overestimated the significance of iron oxides in
the retention of molybdenum by Kenyan soils.
Citation
Master of ScienceSponsorhip
University of NairobiPublisher
The Faculty of Graduate Studies of The University of Guelph