The Study In Hydrolysis Of Cellulose And Hemicellulose From Luffa Fibers By Plasma Acid

Plasma acid was obtained by treating distilled water with dielectric barrier discharge. Ithas many advantages over traditional inorganic acid with the properties of lower cost andachieved easily. It is a green and environmentally friendly method to hydrolyze biomass fibers.In this paper, the plasma acid was achieved and applied to hydrolyze hemicelluloses，celluloseand luffa fibers through an orthogonal experiment L25（53）. The hydrolysis sample wascharacterized by DNS method, High-performance liquid chromatography (HPLC) andFourier transformed infrared spectroscopy (FTIR). The main conclusions of this article wereas follows:5ml distilled water was treated by dielectric barrier discharge (power80w, discharge gap8mm) for different time. The pH values were tested and the relation curve was drawn. Theresults showed pH value varied dramatically from6.83to1.66during the initial dischargeprocess (10s-90s). And it changed slightly after90s with1.66to1.35. Obviously, the pHvalue was affected by discharge time greatly at first and then the influence weakened.The plasma acid (pH=1.42) was acquired by dielectric barrier discharge (power80w,discharge gap8mm, discharge time120s). The pH value was tested every hour and thevariation curve was drawn. It showed the pH value hardly fluctuated within2hours and itfaded generally and tended to be neutral.Plasma acid was applied to hydrolyze hemicellulose through an orthogonal experimentL25（53）. The hydrolysis sample was analyzed by DNS method, High-performance liquidchromatography (HPLC) and Fourier transformed infrared spectroscopy (FTIR). The resultsshowed that pH2.81of plasma acid,100℃and50min were assigned as an optimalhydrolysis condition by plasma acid. Under this condition, the hemicellulose was hydrolyzedto produce monosaccharides including xylose, glucose, and galactose with the mole ratiobeing17:3:1. The yield of xylose was38.67%. It was more efficient than sulfuric acidhydrolysis method. The results of hydrolysis kinetics showed the hydrolysis rate ofhemicelluloses to produce xylose was much faster than the degradation of xylose. Cellulose (0.1g) was hydrolyzed by plasma acid (10ml) and the hydrolysis sample wasanalyzed by DNS method, HPLC and FTIR. The optimum conditions were as follows: the pHof plasma acid was1.42, the hydrolysis temperature was80℃and the hydrolysis time was50min. The hydrolysis sample contained glucose and xylose with the mole ratio being50:1.And the yield of glucose was46.05%. Therefore, the cellulose can be hydrolyzed to produceglucose efficiently.Luffa fibers were pretreated by atmospheric dielectric barrier discharge (power110w,discharge gap6mm, discharge time10s) to remove a small amount of hemicelluloses andlignin in order to contribute to be hydrolyzed by plasma. An an orthogonal experiment L25（53）was applied to get the optimum conditions. The result showed the pH1.66of plasmaacid,100℃and50min were considered to be the optimum hydrolysis condition. Thehydrolysis sample contained glucose, xylose and mannose with the mole ratio being213:6:1.And the yield of glucose was58.38%. It can be concluded from he results of hydrolysiskinetics that the higher the temperature was, the more dramatical the hydrolysis process wasand the shorter of the time to reach to hydrolysis balance.