Permeation and diffusion of environmental pollutants through flexible polymers

Abstract

SynopsisPermeation and diffusion characteristics of high density polyethylene (HDPE), elasticized polyolefin, and polychloroprene membranes have been determined for various organic pollutants at 22 and 50°C. A standard ASTM permeation cell method was used to measure the permeation rate while an immersion/weight gain method was used to obtain the diffusion coefficient. Thickness-dependent permeation rates were determined for HDPE membranes. An equimolar mixture of various permeants was also used to see the possibility of synergistic effects by combination of permeants. The experimental results are discussed in relation to the suitability of HDPE membranes in severe environments.

Resistance of barrier elastomers to hazardous organic liquids

“…However, concentration dependence of diffusion does exist with some of the polymer-solvent systems. As a rough approximation, the diffusion coefficients D, have been estimated from the Fickian model by using the relationship, [13][14][15][16][17][18] …”

Diffusion and solubility coefficients determined by permeation and immersion experiments for organic solvents in HDPE geomembrane

“…Several researchers have conducted immersion tests to obtain the solubilities of chemical in polymer membranes [10,11,15]. In their studies, solubility S i was estimated using the equilibrium sorption data as follows…”

“…(2) are assumed to be equal to the solubility, S i (ML −3 ), of organic solvent in polymer membrane at any time. By plotting C i against the square root of time, the diffusion coefficient, D i (L 2 T −1 ), of organic solvent in polymer membrane with initial thickness of L can be estimated using the sorption curve as follows [2,[7][8][9][10][11]16,17]:…”

“…The immersion method is a simple and expedient gravimetric test [6,11]. In contrast to the ASTM F739 method, both surfaces of geomembrane sample are in contact with the tested chemical for immersion method.…”

“…The geomembranes sample is immersed in a sealed container and weighted at specified time intervals. Several researchers have estimated the diffusion and solubility coefficients of organic solvents in geomembrane using the gravimetric test [2][3][4][7][8][9][10][11].…”