Abstract: 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 O₄ indicates that little hydroxyl groups and adsorbed water are present in the samples.

Key words: bio-oil, pyrolytic lignin, Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy

摘要： 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 O₄ indicates that little hydroxyl groups and adsorbed water are present in the samples.

关键词: bio-oil, pyrolytic lignin, Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy