The Study Of Wood Fiber Cell Dissolved With [BMIM] Cl-H₂O System

As the increasing depletion of coal, oil and other petrochemical resources and thedemand for energy continues to increase, crop stalks and other natural lignocellulosic biomassas renewable energy, has begun to attract more and more attention. Cellulose, hemicellulosefrom straws can be converted into fuel ethanol and sugar, and lignin can be used to producepolymer materials, so the crop stalks has broad application in many area. But the separation ofthe three constituents from straws needs complex preprocessing. Preprocessing techniques indealing with existing conditions, environmental pollution, and other aspects of the productioncosts, has many problems.In order to provide a viable reference to straw pretreatment technology, this paper choosethe soybean straw as raw materials, and the ionic liquid-water as a solvent, pretreated thestraw under relatively mild conditions. And then we analyzed the content of the threeconstituents, and the change of cellular microstructure before and after pretreatment instraws.At the same time, enzymatic hydrolysis of the straw residue were analyzed. Theresults were as follows:Pretreated with different concentrations of [BMIM]Cl-H2O system under90oC for8h,the three components are dissolved. As the [BMIM]Cl concentration decreased, dissolvingcapacity of the components s first increased and then decreased, and the componentsdissolved the most at80%. Pretreated with80%[BMIM]Cl-H2O system under90oC, and thetime extended from1h to8h, cellulose and lignin dissolved more in2h. As time extended, thedissolving ability of constitutes decreased and didn‘t change any more after8h. Rising thetemperature could improve dissolving capacity too, and it didn‘t change remarkably after120oC.Pretreated with [BMIM]Cl-H2O mixtures could remove part of the lignin, opening the pitmembranes and increasing specific surface area that increased the accessibility of celluloseand hemicelluloses. Meanwhile, the cellulose crystallinity declined and that make it moreeasily for enzymatic hydrolysis. The saccharification yield was71.1%when the soybeanstraw was pretreated with80%[BMIM]Cl-H2O mixture at90oC for8h, while the rawmaterial was21.0%.