Bio-oil is a new liquid fuel produced by fast pyrolysis

which is a promising technology to convert biomass into liquid. Pyrolytic lignin extracted from bio-oil

a fine powder

contributes to the instability of bio-oil. The paper presents the structural features of three kinds of pyrolytic lignin extracted from biooil with different methods(WIF

HMM

and LMM). The pyrolytic lignin samples are characterized by Fourier transform infrared spectrometer(FTIR) and X-ray photoelectron spectroscopy(XPS). FTIR data indicate that the three pyrolytic lignin samples have similar functional groups

while the absorption intensity is different

and show characteristic vibrations of typical lignocellulosic material groups O—H(3340-3380 cm

-1

)

C—H(2912-2929 cm

-1

) and C=O(1652-1725 cm

-1

). Comparison in the region(3340-3380 cm

-1

) indicates that WIF has more O—H stretch groups than HMM and LMM. The carbon spectra are fitted to four peaks:C1

C—C or C—H

BE 283.5 eV;C2

C—OR or C—OH

BE 284.5-285.8 eV;C3

C=O or HO—C—OR

BE 286.10-287.10 eV;C4

O—C=O

BE 287.5-287.7 eV. The absence of C1

C—C or C—H indicates the dominant polymerization structure of aromatic carbon in pyrolytic lignin samples. For HMM and WIF

C2a and C2b can not be separated

so there is no free hydroxyl group in the samples. The oxygen peaks are also fitted to four peaks:O1

—OH

BE=530.3 eV;O2

RC=O

BE=531.45-531.72 eV;O3

O—C=O

BE=532.73-533.74 eV;O4

—H2O

BE 535 eV. The absence of O1 and O

4

indicates that little hydroxyl groups and adsorbed

water are present in the samples.