Geomembranes containing powdered activated carbon have the potential to improve containment of chlorinated aromatic contaminants.
Breakthrough across high-density polyethylene (HDPE) was measured for 2,3',4',5-tetrachlorobiphenyl and a higher-solubility surrogate, 1,2,4-trichlorobenzene. Addition of powdered activated carbon (0.14 g carbon/cm(3) membrane) reduced pseudo-steady-state flux through thin HDPE membranes by approximately 60%. Breakthrough curves for activated carbon-containing membranes were best described by a model in which sorption to the carbon was limited by the rate of diffusion from the bulk membrane to the carbon particle surfaces. Field-scale estimates based on this model show a substantial (over 10 orders of magnitude) reduction in flux for the activated carbon-containing HDPE compared with pure HDPE. The flux of 2,3',4',5-tetrachlorobiphenyl through a composite membrane with thin layers of poly(vinyl alcohol) (PVA) with 0.05 g carbon/cm(3) and pure HDPE was 69% lower than expected for a similar layered membrane without the sorptive scavenger. This flux reduction was achieved with less than a third of the carbon used in the HDPE case, an improvement that is likely the result of better solute uptake in the hydrophilic PVA layer.
Surdo
Erin M
EM
Department of Civil Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Cussler
Edward L
EL
Novak
Paige J
PJ
Arnold
William A
WA
D000096:Acetone / Q000737:chemistry; D002606:Charcoal / Q000737:chemistry*; D004058:Diffusion; D004777:Environment; D004785:Environmental Pollutants / Q000302:isolation & purification*; D006841:Hydrocarbons, Aromatic / Q000302:isolation & purification*; D006846:Hydrocarbons, Halogenated / Q000302:isolation & purification*; D007700:Kinetics; D008567:Membranes, Artificial; D008956:Models, Chemical; D020959:Polyethylene / Q000737:chemistry; D011142:Polyvinyl Alcohol / Q000737:chemistry; D011208:Powders; D014867:Water / Q000737:chemistry
D004785:Environmental Pollutants; D006841:Hydrocarbons, Aromatic; D006846:Hydrocarbons, Halogenated; D008567:Membranes, Artificial; D011208:Powders; D014867:Water; D000096:Acetone; D002606:Charcoal; D020959:Polyethylene; D011142:Polyvinyl Alcohol