Evaluation of granular activated carbon, shale and two organoclays for use as sorptive amendments in clay landfill liners

Shannon L. Bartelt-Hunt, James A. Smith, Susan E. Burns, Alan J. Rabideau

Research output: Contribution to journalArticlepeer-review

64 Scopus citations


Four materials with high sorptive capacities for organic compounds [granular activated carbon (GAC), shale, benzyltriethylammonium-bentonite (BTEA-bentonite), and hexadecyltrimethylammonium-bentonite (HDTMA-bentonite)] were evaluated for their use in compacted clay landfill liners by conducting laboratory sorption and permeability experiments with both a 0.002 N CaSO4 solution (to simulate the ionic strength of ground water) and a synthetic leachate. Results from equilibrium sorption experiments with 0.002 N CaSO4 indicate that all four amendments have a very high sorptive capacity for the three organic solutes tested: benzene, trichloroethylene, and 1,2-dichlorobenzene. GAC exhibited the highest sorptive capacity for all three solutes, followed by BTEA-bentonite, HDTMA-bentonite, and shale. Experiments conducted with synthetic leachate indicate that GAC and BTEA-bentonite did not exhibit competitive sorption effects with the synthetic leachate constituents, while shale did exhibit some competitive sorption effects between benzene and trichloroethylene and the synthetic leachate constituents. Permeability tests conducted on specimens composed of Ottawa sand, untreated bentonite, and either 3 or 9% amendment by weight were also performed. Results indicate that all amended specimens had a hydraulic conductivity less than or equal to 1 × 10-7 cm/s, with the exception of the specimen amended with 3% GAC, which had a measured conductivity value of 2 × 10-7 cm/s. Changing the permeant fluid to a synthetic leachate had little effect on the overall conductivity of the specimens. One-dimensional benzene transport simulations were performed to more completely evaluate how effective these materials would be if incorporated into a compacted clay liner. Simulations indicated that all proposed amendments would effectively retard the transport of benzene through the liner. Amending liners with 3 or 9% GAC or 3 or 9% BTEA-bentonite effectively eliminated benzene flux through the liner over a 100-year period. Liners amended with HDTMA-bentonite or shale also reduced the benzene flux exiting the liner over the simulation period, but to a lesser extent.

Original languageEnglish (US)
Pages (from-to)848-856
Number of pages9
JournalJournal of Geotechnical and Geoenvironmental Engineering
Issue number7
StatePublished - Jul 2005
Externally publishedYes


  • Activated carbon
  • Benzene
  • Clay liners
  • Leaching
  • Permeability
  • Shale
  • Sorption
  • TCE

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • General Environmental Science


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