Molybdenum Adsorption by Volcanic Italian Soils

Abstract

Molybdenum (Mo) adsorption was investigated on five soils from the Gauro and Roccamonfina volcanoes of Campania, a southern Italian volcanic region. The soils were characterized by different degrees of development. Molybdenum adsorption exhibited a maximum near pH 4–5 and decreased with increasing pH above 5. The constant capacitance model was able to fit Mo adsorption on the soils as a function of pH. A general regression model was used to predict a Mo surface complexation constant from routinely measured soil chemical parameters. The predicted Mo constant was used to predict adsorption on the soils, thereby providing a completely independent evaluation of the ability of the model to describe Mo adsorption. The prediction equation, developed from a set of soils primarily from California, was able to predict Mo adsorption on four out of five soils from Italy, suggesting wide applicability for describing Mo adsorption by soils of diverse mineralogy and parent material.

Keywords:

• Andisols
• constant capacitance model
• molybdate
• sulfate

Notes

¹Trade names and company names are included for the benefit of the reader and do not imply any endorsement or preferential treatment of the product listed by the U.S. Department of Agriculture.