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Pyrene Sorption to and Extraction from Corn Stover Char

Pyrene Sorption to and Extraction from Corn Stover Char. Tom Holm Mike Machesky John Scott. Biochar preparation. Corn stover Pyrolysis 450°C 550°C 750°C N 2 atmosphere. usepa-16 pah content of corn stover char. See John Scott’s Poster!!. Sorption isotherm 450° char.

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Pyrene Sorption to and Extraction from Corn Stover Char

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  1. Pyrene Sorption to and Extraction from Corn Stover Char Tom Holm Mike Machesky John Scott

  2. Biochar preparation • Corn stover • Pyrolysis • 450°C • 550°C • 750°C • N2 atmosphere

  3. usepa-16 pah content of corn stover char See John Scott’s Poster!!

  4. Sorption isotherm 450° char r2 0.96

  5. sorption isotherms, fresh char

  6. Bioavailability-related Experiments • Mild extractions with 2-hydroxypropyl-b- cyclodextrin (HPCD) • HPCD-extractable PAHs correlate well with • Bioavailability • Biodegradation • Poor correlation with total PAH content

  7. Hpcd-extractable pyrene450° char Native pyrene

  8. Artificial aging • Hale et al. (2011) • 40% field capacity (moisture) • Incubate 1 month • Freeze/Thaw • 60°C • 110°C

  9. Sorption isotherms,aged and fresh 750° Char

  10. Hpcd-extractable pyrene450° char, fresh & aged

  11. Hpcd-Extractable pyrene550° char, fresh & aged

  12. Conclusions, pah sorption • PAHs sorb strongly to corn stover char • Freundlich isotherm • 6 < Log K < 7 for fresh char • For native PAHs, solubility << 1 ng/L

  13. Conclusions, pah bioavailability • Small fraction of pyrene is bioavailable (HPCD-extractable) • 10-15% 450° char • 1-3% 550°, 750° chars

  14. Conclusions, char aging • (Artificial) aging has small effects on PAH sorption • DLog K for pyrene ≤ 0.5 • Aging effect on PAH bioavailability • 450° char: decrease • 550° char: large decrease (?) • 750° char: no effect

  15. Water-soluble black carbon DOC 9.8 mg/L pH 9.2

  16. Absorbance Spectum,water extract of cs450

  17. Fluorescence Excitation-Emission Spectra CS450 Water Extract Groundwater, Champaign Co.

  18. Base titration, water extract of CS450

  19. Aknowledgements • Will Gillespie, ISWS, for corn stover • B. K. Sharma & Wei Zheng for biochar pyrolysis • Jill O’Connell for assistance with experiments • Illinois Sustainable Technology Center for project support

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