关键词: 苎麻骨, 对甲苯磺酸, 纤维素, 脱胶

Abstract: Lignocellulosic biomass is a green and degradable carbon neutral resource that contains components such as cellulose to provide sustainable raw materials for the production of biofuels and chemicals. Ramie bone is a cellulose-rich agricultural waste mainly composed of cellulose, lignin and hemicellulose. Cellulose, hemicellulose and lignin are physically and chemically cross-linked and entangled with each other to form a dense supramolecular complex structure that resists damage from the outside world. The complex structure of biomass dictates that it needs to be treated to break the barrier of biomass against depolymerization and to achieve separation of cellulose and other components. The p-toluenesulfonic acid is an acid hydrotropes solvent that forms a colloid with lignin at its hydrophobic end to dissolve lignin, and dissociates hydrogen ions from the hydrophilic end to attack hemicellulose, leaving the cellulose as a solid residue. However, previous studies have tended to focus on the extraction and characterization of lignin using p-toluenesulfonic acid, with less attention being paid to the solid fraction of cellulose. In this study, we used p-toluenesulfonic acid combined with hydrogen peroxide in a one-step treatment of ramie bone to investigate the effects of p-toluenesulfonic acid concentration, hydrogen peroxide concentration, temperature and time on the degumming effect. The results showed that 95.90% of the lignin in ramie bone was dissolved and the cellulose content increased to 80.79% with 75% mass concentration of p-toluenesulfonic acid and 3% volume fraction of H2O2 at 75°C for 80 min, which was 37.61% higher than the original sample. Due to the removal of non-fibrous components, the thermal stability of ramie bone was improved and the surface changed from smooth to rough. Meanwhile, the results of infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis indicated that the combination of p-toluenesulfonic acid and hydrogen peroxide disrupted the structure of ramie bone and promoted the dissolution of lignin. This provides a simple and effective way for the utilization of ramie bone.

Key words: ramie bone, p-toluenesulfonic acid, cellulose, degumming