Choline chloride-based deep eutectic solvents for extraction of cellulose from sugarcane bagasse

Plant biomass or lignocellulose is the most abundant renewable material that is primarily composed of polysaccharides (cellulose and hemicelluloses) and an aromatic polymer of lignin. Sugarcane bagasse is a large-volume agriculture residue produced from the sugar industry in Thailand and rich in cellulose (40-50%). Recently, the fractionation of cellulose from sugarcane bagasse has been attractive and gained great attention in the field of green and sustainable chemistry. In recent years, deep eutectic solvents (DESs) have been used in various fields, especially in the chemistry of extraction and separation of components from biomass due to being considered as green solvents and environmentally friendly technology. In addition, DESs are easy to prepare with a short preparation time, low cost, biodegradable, low toxic, and recyclable. DESs can be formed between hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA). In the present work, choline chloride (ChCl)-based deep eutectic solvents was used as the HBA and different types of acid compounds used as the HBD to extract the cellulose fiber. DESs were prepared by heating on a hotplate at 100 °C for 30 min under stirring conditions. Sugarcane bagasse was pretreated using liquid hot water (LHW) at 170 °C for 40 min in a hydrothermal reactor. After that, it was treated with DESs at 130 °C for 3 h to separate lignin from sugarcane bagasse fiber to get cellulose-rich. Experiments revealed that the DESs treatment (various acidic compounds) were able to remove lignin and hemicellulose. Moreover, the chemical structures of the obtained cellulose were characterized by Fourier-transform infrared spectroscopy (FT-IR) and X-Ray Diffraction (XRD).