Desorption of Polychlorinated Biphenyls from Contaminated St. Lawrence River Sediments with Supercritical Fluids

Wu Zhou, Gheorghe Anitescu, Lawrence L. Tavlarides

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Laboratory- and bench-scale polychlorinated biphenyl (PCB) desorption experiments using supercritical fluids are conducted on air-dried, contaminated St. Lawrence River sediments (SLRS) to demonstrate the remediation and scale-up potential of the process. Laboratory-scale desorption experiments reveal that PCB concentrations can be reduced from 2200 ppm to less than 5 ppm in 60 min (99.77% extraction efficiency) when supercritical CO2 with 5 mol % methanol is used at 118 bar and 323 K. Similar or better results are achieved at a bench-scale size of 2 L volume (400 × scale-up) under similar conditions. It is found that the PCB concentration in the sediments can be reduced from 1840 ppm to less than 5 ppm in ∼40 min (>99.73% extraction efficiency), The final PCB concentrations after 60 min of extraction are around 3 ppm, which is comparable with the final PCB concentrations of ∼4 ppm for the laboratory-scale experiments (when the supercritical fluid is CO 2MeOH). These results suggest that the scale-up factors are not significant over this range on the desorption processes of PCBs from real-world SLRS. A two-step linear driving force model is shown to predict well the benchscale desorption results when using a model obtained independently and the effective diffusion coefficients and mass-transfer coefficients determined from the laboratory-scale information.

Original languageEnglish (US)
Pages (from-to)397-404
Number of pages8
JournalIndustrial and Engineering Chemistry Research
Volume43
Issue number2
DOIs
StatePublished - Jan 21 2004

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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