Enhanced Cellulose Dissolution And Regeneration In Ionic Liquid

Rapid and efficient dissolution of natural cellulose in most solvents is still challenging due to its highly ordered crystalline structure.In this paper,an efficient cellulose dissolution system incorporating acid and 1-butyl-3-methylimidizolium chloride?BmimCl?was developed.The results showed that aqueous H₂SO₄ solution could enhance cellulose dissolution in BmimCl,however,severe hydrolysis and degradation of cellulose also occurred.Comparatively,dissolution with solid acid addition could avoid this phenomenon.Indeed,addition of solid acid?SA?both Amberlyst^?15 and Cs_xH_3–xPW₁₂O₄₀ was found to significantly enhance cellulose dissolution in BmimCl.In contrast to BmimCl system,SA/BmimCl system for cellulose dissolution had advantage of high efficiency,mild conditions and facile recovery of solvents.Characterization of the regenerated celluloses showed that SA/BmimCl is a non-derivatizing solvent for cellulose,which favored the complete dissolution of the natural cellulose.Therefore,SA/BmimCl systems is a promising and effective solvent system for biomass processing due to its low cost and environmentally friendliness,which would greatly broaden the utilization of lignocellulosic resources.Effect of anti-solvent on structure and enzymatic hydrolysis of the regenerated cellulose from IL was investigated,where water,ethanol,acetone and DMF were used as anti-solvent.The structure of the original and regenerated cellulose was characterized by degree of polymerization?DP?,X-ray diffraction?XRD?,environment scanning electron microscopy?SEM?,?Thermogravimetric?TGA and Fourier Transform Infrared Spectroscopy?FT-IR?analysis.The results showed that the crystalline cellulose I of the original cellulose was transformed into the crystalline cellulose II after regeneration.Compare to that of the original cellulose,crystallinity,DP,yield and thermostability of the regenerated celluloses using water,ethanol,acetone and DMF as anti-solvent were lowered,which closely correlated with the type of anti-solvent.In addition,the specific surface area and porosity of the regenerated celluloses increased.The structural change due to dissolution and regeneration are favorable to the following enzymatic hydrolysis,and ration of the released glucose in hydrolysate ranged from 21.64%to 30.25%.Among the investigated anti-solvents,the regenerated cellulose showed excellent properties using DMF/water?1/1,v/v?as anti-solvent,which provided a theoretical basis for efficient fabrication of cellulose derivatives.