Determining the Transport Through Geomembranes of Various Permeants in Different Applications

Abstract

The widely different uses of geomembranes as barriers to the transport and migration of different gases, vapors, and liquids under different service conditions require a determination of permeability by test methods appropriate to the service. Geomembranes are nonporous and homogeneous materials that permeate gases, vapors, and liquids on a molecular scale by dissolution in the geomembrane and diffusion through the geomembrane. The rate of transmission of a given species, whether as a single permeant or in mixtures, is driven by its chemical potential or concentration gradient. Various methods to assess the permeability of geomembranes to single component permeants, such as individual gases, vapors, and liquids are described and data are presented. In addition, various test methods for the measurement of permeation and transmission through geomembranes of individual species in complex mixtures such as waste liquids are described and data are presented.

Viscoelastic (Non‐Fickian) Diffusion

“…The analysis of the permeant on the downstream side is required, due to the selective nature of the polymeric membranes, which result in species dependent transmission rates. 139 Analytical tools such as gas chromatography, 140 FTIR or GC mass spectroscopy for organics and atomic absorption for inorganics are often used to detect, identify and quantify the permeant. 141 August and Tatsky 142 measured the transmission rates of six solvents through a 1.0 mm thick HDPE geomembrane.…”

“…146 The results from this work and similar experiments with gasoline and HDPE geomembranes indicate that the strong selectivity by the geomembrane may lead to very different permeation rates for the components of mixtures. 139,[147][148][149] The results from these studies allow one to conclude that significant quantities of an organic can permeate through a geomembrane due to selective permeation, even when the organics are present at low concentration.…”

A Importância Das Plantas Alimentícias Não Convencionais (Pancs) Para a Sustentabilidade Dos Sistemas De Produção De Base Ecológica

“…Assim, percebe-se que o teor de cloreto difundido pela geomembrana de PEAD é mínimo. Este resultado é compatível com os resultados obtidos por Rowe et al (1995) e Haxo (1990) que demonstraram que a difusão de íons cloreto através da geomembrana é praticamente desprezível.…”

Non-Fickian diffusion in systems with complex interfaces

“…63 Analytical tools such as gas chromatography, 64 FTIR or GC mass spectroscopy for organics and atomic absorption for inorganics are often used to detect, identify and quantify the permeant. The analysis of the permeant on the downstream side is needed because of the selective nature of polymeric membranes, which result in different transmission rates for different chemical species.…”