Effect of Alkali and 1,4-Butanediol Contents on the Extraction of Lignin and Lignin-Based Activated Carbon.

In the process of lignin extraction by the organic solvent method, the amount of alkali and the content of 1,4-butanediol are important conditions that affect lignin yield. The effects of alkali and alcohol contents on lignin recovery, removal rate, and structure were studied. In this reaction system, the removal rate of lignin increased with the increase of alkali content but decreased with the increase of alcohol content. Fourier transform infrared (FT-IR) analysis showed that the phenol hydroxyl group and the ether bond in lignin had different trends in different alkali and 1,4-butanediol environments, and four different infrared parameters in lignin had an obvious linear relationship. Gel permeation chromatography (GPC) results showed that high alkali content and high 1,4-butanediol content could lead to the fragmentation of lignin. In addition, lignin extracted from alkali-quantity factor series was selected to prepare activated carbon, CaCl was selected as the activator, and its effects were studied. Results showed that in the process of extracting lignin, on the one hand, NaOH content affects the functional groups of activated carbon by affecting the aromatic structure of lignin; on the other hand, the NaOH content affects the graphitization degree and specific surface area of activated carbon by affecting the removal rate and the molecular weight of lignin.