The Fractionation And Characterization Of New Novel Organic Electrolyte Lignin And Study On It’s Application

The energy needs of our society, are currently over-dependent on the utilizationof fossil resources which are quickly decreasing. Biomass as a renewable carbonresource has attracted considerable attention, to build new environmental friendlymaterials, chemicals and energy.The lignocellulose is the largest biomass resource. However, it is composed ofcomplex molecules with three-dimensional stiff structural characteristics such ascellulose, hemicelluloses and lignin making it difficult to be fractionated, therefore,the development of mild and clean pretreatments to selectively fractionatelignocelluloses is still a challenge towards a foundation of cost-competitivebiorefinery.Based on the concept of “biomass-to-biodiesel” in our laboratory, this thesisfocused on the development of a low-cost and highly efficient pretreatment oflignocellulose to separate it in its main components, as well as extraction of lignin andits characterization. For that purpose, the lignocellulose was treated in an organicelectrolyte solution, studied the separation and characterization of the resultantproducts, especially lignin as it is a green catalyst in CO₂fixation. The main researchcontents of the manuscript are divided as follows:1. Corn stover and spruce thermomechanical pulp were selected as lignocellulosematerials source. Such materials were treated using as organic electrolyte solution amixture of cheap aprotic organic solvents with a ionic liquid （such as EmimAc,NH4Ac and LiAc）. The organic solvent to ionic liquid molar ratio was fixed to20%.The pretreatment was performed at140oC. The influence of the organic electrolytesolution composition and the dissolution time on the ability to separate thelignocellulose components were examined. The results showed that the sugar yields ofregeneration materials using an organic electrolyte solution with different polaraprotic solvents and EmimAc were almost the same. Moreover, the hydrolysis ofcarbohydrates in pretreated substrates reached almost full conversion within24h andthe use of an organic electrolyte solution of EmimAc and DMSO allowed a highlignin removal ability.2. By means of extraction, using an enzymatic hydrolysis methodology; wecould easily separate the lignin components. Two fractions were obtained: the Enzymatic hydrolysis lignin （EHL） and ionic liquid extracted lignin （IEL）. The twolignin samples were characterized by Fourier transform infrared （FT-IR） andthermogravimetric analysis （TGA）, nuclear magnetic resonance （1H NMR,2D13C-1HNMR,31P NMR）, gel permeation chromatography （GPC）, and other methods. Forexample,31P NMR analysis of EHL shows that the contents of aliphatic hydroxylgroups, phenolic hydroxyl groups and carboxylic groups are2.96mmol/g,0.30mmol/g, and0.09mmol/g, respectively.3. Based on the31P NMR characteristics of the lignin structure obtained from theenzymatic hydrolysis, we conducted a preliminary exploration of its potentialapplication in CO₂fixation.As conclusion, we developed a low cost method to completely dissolvedlignocellulose materials through using an organic electrolyte solution. As a result, ahighly efficient separation of the lignin materials in mild conditions and itssubsequently activation were achieved. The structural elucidation of the lignin wasalso accomplished. The methodologies used during this research work provide animportant platform for the homogeneous process of biomass and its utilization.