Study on structure and pyrolysis behavior of lignin derived from corncob acid hydrolysis residue

The structure and pyrolysis charateristics of lignin isolated from corncob acid hydrolysis residue (CAHL) were studied. Characteritic bands corresponding to guaiacyl and syringyl groups were detected by FTIR, and CAHL particle was polygonal in shape with multiple conchoidal fracture surface. Result of TGA showed that CAHL underwent thermo-degradation at a wide temperature range of 180–850 °C, and two mass loss peaks were observed at 237 °C and 340 °C. Evolution of methanol and phenols were mainly detected at 150–420 °C, while CO2, CO and CH4 appeared to be the main gaseous products at temperature above 400 °C. Py-GC/MS analysis showed that phenolic compounds, mainly consisting of guaiacol- and syringol-type, were generated from cracking of arylglycerol-β-ether (β-O-4) linkage in CAHL. SEM analysis showed that portoins of CAHL char appeared brittle with conchoidal fractures at 550–750 °C, and vesicle was observed due to plastic formation above 850 °C.

► Lignin isolated from corncob acid hydrolysis residue (CAHL) is characterized.
► CAHL particle is polygonal and bands corresponding to guaiacyl and syringyl groups are detected.
► CAHL undergo thermo-degradation at 180–850 °C and two mass loss peaks are observed.
► Evolution of methanol and phenols at 150–420 °C, while that of CO2, CO and CH4 mainly above 400 °C.
► CAHL char appears brittle at 550–750 °C, and vesicle is formed above 850 °C.