Organic solvent-assisted ethylenediamine pretreatment to improve the high-value utilization efficiency of corn stalk

Abstract

In order to achieve the goal of carbon neutrality, it is an important way and a great challenge to realize the full-component conversion of lignocellulosic biomass via bio-refinery. In this study, the pretreatment method of organic solvent-assisted ethylenediamine was used to separate cellulose, hemicellulose, and lignin in corn stalk. The effects of different organic solvents on the separation ability were studied, and the separated products were transformed into high-value products. Specifically, the structures of solid residue, regenerated hemicellulose, and regenerated lignin were analyzed and applied to pyrolysis saccharification (at 500℃ for 30 min), information anti-counterfeiting, and selective detection of Fe3+ respectively. The results showed that the lignin removal ratio of 1-butyl-3-lethylimidazolyl chloride/ethylenediamine (IL/EDA) system could reach 96.05 % under the pretreatment condition of 200℃ for 2 h, and the yield of Levoglucosan obtained from pyrolysis bio-oil reached 169.70 mg·g−1 with high selectivity. Moreover, IL/EDA pretreatment increased the nitrogen content of lignin and hemicellulose, enhanced the fluorescence intensity, and effectively realized selective detection and information encryption. Furthermore, Density functional theory (DFT) calculation proved that the addition of organic solvents was beneficial to the reaction between lignin and ethylenediamine (EDA). The Fukui function was used to explore the reaction site between EDA and lignin. In addition, the mass balance of the pretreatment process was also described. This study realized the high-value application of all components of lignocellulose and provided a new process for the efficient utilization of green carbon resources.