Abstract:

Lignin is a natural phenolic polymer abundant in corn stover. It plays an important role in the synthesis of
adsorbents, dye dispersants, concrete water-reducing agents and many others in the field of chemical industry. In this work,
we developed a method to extract lignin from corn stover by means of alkaline solubilization, alcohol precipitation and
acid separation. Box-Behnken design was applied to optimize the extraction process. The highest lignin yield achieved
was 69.71% under the condition of 2.40 mol/L NaOH at 74 ℃ for 3.10 hours. The resulting lignin was analyzed by using
thermogravimetry (TG), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy.
This lignin was decomposed mainly between 130 and 500 ℃. Some of its functional groups formed a cross-linked complex
with thermal stable structures. The maximum UV absorption occurred at 282 nm. This lignin is very reactive and suitable for
polymer synthesis and modification. Thus, this study provides a new way of utilizing corn stover.

Key words: lignin, corn stover, alkaline solubilization-alcohol precipitation-acid separation, characterization