Method for separating cellulose and lignin from plant fiber raw material by utilizing ion liquid

Abstract

The invention relates to the field of treatment of plant fibers and particularly relates to a method for separating cellulose and lignin from a plant fiber raw material by utilizing ion liquid. According to the invention, the method comprises the following steps of: 1) mixing DMSO (Dimethylsulfoxide) and the ion liquid according to a mass ratio of 1: 4-9 to be used as a solvent, and adding the plant fiber raw material; 2) dissolving at 80 to 140 DEG C for 4-48 hours to obtain a reaction mixed liquid; 3) filtering and separating the reaction mixed liquid by a stainless steel filter screen or a nylon filter cloth, adding water into the obtained filtrate, and depositing a mixed extract of the cellulose and the lignin; 4) washing and extracting a mixed extract of the cellulose and the lignin by a water / DMSO mixed solvent, and filtering to obtain mixed liquid of a cellulose solid and lignin / DMSO / water; 5) drying the cellulose solid to obtain a cellulose product; and 6) decompressing and distilling the mixed liquid of the cellulose / DMSO / water to obtain a cellulose product. The method, provided by the invention, is simple, feasible and high in purity of the obtained cellulose.

Description

technical field [0001] The invention relates to the field of plant fiber treatment, in particular, the invention relates to a method for separating cellulose and lignin from plant fiber raw materials by using ionic liquid. Background technique [0002] With the increasingly serious consumption of fossil resources and environmental pollution, as well as the gradual enhancement of the concept of sustainable development and environmental protection awareness, the research and development of products and related processes prepared from renewable biomass resources have attracted more and more attention from the world. The potential amount of woody biomass is very sufficient. The plant fiber raw material produced by photosynthesis is about 180 billion tons per year, which is equivalent to 10 times the total annual energy consumption in the world. Therefore, it is imperative to replace fossil resources with woody biomass resources. . The main components of plant fiber raw material...

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Problems solved by technology

None of the above involves the cellulose purification process and the lignin extraction method;

[0005] The 2005 patent (application number: PCT / FI2004 / 000476) disclosed a method for dissolving lignocellulosic raw materials with ionic liquids, but did not effectively separate and regenerate lignin or cellulose

[0006] In the patent whose application number is 200910012002.1, it is mentioned that a mixture of imidazole compounds and water is used as a solvent to dissolve and separate plant materials. During the separation and extraction of lignin and cellulose, it was found that water was added to the ionic liquid as a solvent, which had a low dissolving ability for plant materials, so that the extraction rate of lignin and cellulose was very low; at the same time, according to the patent The dissolution time given can not achieve good results

Therefore, carry out experiment by the condition that this patent gives, can not obtain good effect

[0007] In addition, when only ionic liquids are used to dissolve plant materials, due to the high viscosity of ionic liquids, it is difficult to achieve solid-liquid separation through filtration after the reaction, which brings great difficulties to subsequent separation operations. Therefore, in order to To overcome the above-mentioned problems, the inventors of the present invention have carried out experimental investigations on the screening of diluents, the reasonable mass ratio of diluents and ionic liquids, and the impact on subsequent separation operations of lignin and cellulose

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