Comparison of soil specific surface area through N2, H2O and EGME adsorption. (5632)
Authors:
P. Castiglione* - Montana State University J.M. Wraith - Montana State University D. Or - University of Connecticut
Abstract:
Soil specific surface area (SA) is often referred to as an operational concept, as its estimate strongly depends on sample preparation and measuring technique. In particular, the results obtained with adsorption methods depend on organic matter content and species of native cations, which both affect the mechanics of adsorption of the chosen probe molecule. We tested three common methods for measuring SA, namely dinitrogen gas, EGME, and water vapor adsorption, on mono-ionic and organic matter-free systems. The results were compared to reference values of SA obtained directly from particle size distribution and soil mineralogy. Nine sand-clay mixtures and six soils of varying texture from Montana (USA) were used. Soils were pre-treated to remove organic matter and most metal hydroxides then
saturated with Ca. Values of SA estimated with different methods were correlated to each other and to relevant soil properties such as clay content and cation
exchange capacity. The results showed that water vapor and EGME SA estimates are in close agreement in absence of organic matter. Also, a reasonable estimation of SA for the investigated soils could be inferred from the air-dried soil water content.
Speaker Information: Paolo Castiglione, Montana State University, 818 Leon Johnson Hall, MSU, Bozeman, MT 59715; Phone: 406-994-7737; E-mail: [email protected]
Session Information: Wednesday, November 3, 2004, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 2810)
Keywords: surface area; adsorption; EGME; water vapor
