Experimental study on the separation of bagasse lignin and cellulose by using deep eutectic solvent based on alkaline pretreatment

As a waste biomass resource with abundant production, sugarcane bagasse is rich in cellulose and hemicellulose with relatively low ash and lignin content, and it is important to effectively separate the three major elements of sugarcane bagasse to achieve its high-value utilization. Treating bagasse by using deep eutectic solvents (DESs) is an important method for separating lignin and cellulose. Such technique, which requires mild conditions, has been extensively investigated. In this study, choline chloride (ChCl) was used as the hydrogen bond acceptor, and lactic acid (La) was used as the hydrogen bond donor to synthesize La/ChCl. Alkali-treated bagasse was treated with La/ChCl to remove lignin. The optimal experimental conditions were bagasse:DES ratio of 1:25, temperature of 110 °C, and treatment time of 12 h. The lignin removal rate was 86.7%, and the cellulose content and yield were 85.3% and 89.1%, respectively. Treating alkali-pretreated bagasse with DES efficiently separated cellulose, lignin, and hemicellulose. This study laid the foundation for obtaining high-content cellulose and provided a new method for an efficient utilization of waste bagasse resources.