TY - JOUR

T1 - Applicability of interfacial theories of surface tension to water-repellent soils

AU - Arye, Gilboa

AU - Bachmann, Jörg

AU - Woche, Susanne K.

AU - Chen, Yona

N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2006/9

Y1 - 2006/9

N2 - Most methods used to characterize the magnitude of soil water repellency consist of direct or indirect measurements of the initial advancing contact angle (θ) at the solid-liquid-vapor interface. Aqueous ethanol solutions (AETS) are commonly used as testing liquids having different liquid-vapor surface tensions (γLV); however, θ measurements using AETS have rarely been performed on water-repellent soils (WRS). Measurements of θ in this study were conducted using both the Wilhelmy plate method (WPM) and the CRM (weight-gain capillary rise method) for three natural and four hydrophobized WRS (water-repellent soils). The values of the Young equation (solid-vapor and solid-liquid surface tension) were calculated, and correlated with the Goods-Girifalco interaction parameter, Φ. The factor Φ was found to be a linear function of the solid-liquid surface tension: Φ = 1 - 0.011γSL, with no significant differences between soils. This relation was then used to formulate an ESIT (empirical equation of state of interfacial tension), suggesting that from one universal constant, θ can be predicted as function of γSV. The applicability of the ESIT approach to WRS was found to be inferior, in contrast to its successful use for ideal solid polymers. Nevertheless, it was found that for a water-WRS system, Φ was ∼0.6 rather than 1.0 as previously assumed. Applying Φ = 0.6 was successfully used in predicting γSV as well as the hydrophilic domain of θ vs. γLV for water and AETS.

AB - Most methods used to characterize the magnitude of soil water repellency consist of direct or indirect measurements of the initial advancing contact angle (θ) at the solid-liquid-vapor interface. Aqueous ethanol solutions (AETS) are commonly used as testing liquids having different liquid-vapor surface tensions (γLV); however, θ measurements using AETS have rarely been performed on water-repellent soils (WRS). Measurements of θ in this study were conducted using both the Wilhelmy plate method (WPM) and the CRM (weight-gain capillary rise method) for three natural and four hydrophobized WRS (water-repellent soils). The values of the Young equation (solid-vapor and solid-liquid surface tension) were calculated, and correlated with the Goods-Girifalco interaction parameter, Φ. The factor Φ was found to be a linear function of the solid-liquid surface tension: Φ = 1 - 0.011γSL, with no significant differences between soils. This relation was then used to formulate an ESIT (empirical equation of state of interfacial tension), suggesting that from one universal constant, θ can be predicted as function of γSV. The applicability of the ESIT approach to WRS was found to be inferior, in contrast to its successful use for ideal solid polymers. Nevertheless, it was found that for a water-WRS system, Φ was ∼0.6 rather than 1.0 as previously assumed. Applying Φ = 0.6 was successfully used in predicting γSV as well as the hydrophilic domain of θ vs. γLV for water and AETS.

UR - http://www.scopus.com/inward/record.url?scp=33748526851&partnerID=8YFLogxK

U2 - 10.2136/sssaj2005.0033

DO - 10.2136/sssaj2005.0033

M3 - Article

AN - SCOPUS:33748526851

VL - 70

SP - 1417

EP - 1429

JO - Soil Science Society of America Journal

JF - Soil Science Society of America Journal

SN - 0361-5995

IS - 5

ER -