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| Titel |
Biochar production from coffee residues: Optimization of surface characteristics and sorptive behavior |
| VerfasserIn |
Kalliopi Fotopoulou, Ioannis D. Manariotis, Hrissi K. Karapanagioti |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101825
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| Publikation (Nr.) |
 EGU/EGU2015-1064.pdf |
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| Zusammenfassung |
| Biochar with high surface area is a promising sorbent for environmental remediation and is
produced by heating biomass in an oxygen-limited environment. Knowing the surface
characteristics increases our understanding of biochar interactions with pollutants. The
hypothesis of the present study is that by controlling pyrolysis conditions, the surface
characteristics and subsequently the sorption behavior of produced biochars can be
optimized. Coffee residues were dried overnight at 50oC and then pyrolized into a gradient
furnace at 850oC. Different solid/oxygen ratios during pyrolysis were tested as well as the up
scaling of the process. The biochars produced were systematically characterized for their
surface characteristics such as BET surface area, open surface area, pore and micropore
volume, and average pore size. The effect of pyrolysis on the biochar suspension pH was
examined with the mass addition technique that involves the addition of increasing
amounts of the biochar to bottles containing 0.1 M NaNO3. FTIR analysis was
used in order to determine the functional groups of the coffee residue and of the
biochars. The macrostructure of the biochars was visualized by Scanning Electron
Microscopy (SEM). Total Carbon (TC) in the samples was determined by Carlo Erba
Elemental Analyzer CHNS, EO 1108 after calibration with standard samples. The
sorption behavior of produced biochars was tested with two different pollutants
(Hg(II), phenanthrene) using batch reactors with the same initial single-compound
solution and the same mass of coffee residue and different biochars. The biochars
produced exhibited a wide range of surface area from 21 to 770 m2/g and open
surface area due to macropores from 21 to 65 m2/g. This suggests that the surface
area in the biochars with high surface area results from the formation of pores.
Actually for the biochar with the highest surface area, it was calculated that up to
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