Plasma-assisted cellulose conversion to soluble saccharide

Conversion of cellulose to soluble saccharides is still a challenge due to the existence of strong intermolecular and intramolecular hydrogen bonds within the compound. Microcrystalline cellulose samples were treated by plasma-in-liquid under various diluted acid and alkaline solutions. Experiments were conducted with applied voltage and current at 1–2 kV and 6–8 A, respectively, with a bipolar pulse power supply at a pulse repetition rate of 30 kHz. The crystallinity index calculated by X–ray diffraction indicated that the crystallinity of cellulose decreased from 78% to 56%, while FTIR solid analysis showed that the strength of intermolecular hydrogen bonding was reduced after plasma treatment. From the liquid analysis, soluble sugar molecules were detected after plasma treatment. These results indicated that plasma treatment is effective to partially decompose the strong intermolecular hydrogen bond within cellulose, and further degrade certain amount of long-chain cellulose into smaller molecules such as soluble saccaride molecules.