Search

CN-122011426-A - Method for preparing lignin in-situ light functional material by lignocellulose pretreatment and synchronous classification

CN122011426ACN 122011426 ACN122011426 ACN 122011426ACN-122011426-A

Abstract

The invention discloses a method for preparing lignin in-situ photo-functional material by synchronously grading lignocellulose pretreatment, which comprises the steps of realizing component disassembly by means of pretreatment organic solution high-solid pretreatment consisting of an alkaline catalyst, a solvation organic solvent and water, simultaneously carrying out in-situ solvation reaction on disassembled lignin by the solvation organic solvent while realizing component disassembly by means of alkali action fracture component linkage, inhibiting the shrinkage of disassembled lignin and strengthening the photo-functional effect of the disassembled lignin, simultaneously obviously inhibiting the removal of cellulose and hemicellulose, improving the retention of raw material carbohydrate, and then, realizing in-situ and controllable functional modification on lignin by means of 1-2wt% sodium hydroxide aqueous solution dissolution and water/organic solvent grading.

Inventors

  • TAN XUESONG
  • SU WANTING
  • ZHAO YI
  • XU YUANLONG
  • ZHANG YU
  • ZHUANG XINSHU

Assignees

  • 中国科学院广州能源研究所

Dates

Publication Date
20260512
Application Date
20260320

Claims (9)

  1. 1. The method for preparing the lignin in-situ light functional material by lignocellulose pretreatment and simultaneous classification is characterized by comprising the following steps of: (1) The high-solid pretreatment, namely uniformly mixing a pretreatment organic solution consisting of an alkaline catalyst, a solvated organic solvent and water with a lignocellulose raw material, and stacking for at least 3 days at room temperature under a high solid state with a material liquid-solid ratio of not more than 3 mL/g to obtain a high-solid pretreatment material, wherein the concentration of the alkaline catalyst in the pretreatment organic solution is (0.005-0.05) g/mL, the volume ratio of the solvated organic solvent to water is (0.05-0.4) mL/mL, and the solvated organic solvent is one or more of triethylene glycol, phenoxyethanol, glycerol formal, dihydro-levoglucosone, tetrahydrofurfuryl alcohol, dimethyl isosorbide and phenethyl alcohol; (2) Dissolving lignin, namely adding 1-2wt% of sodium hydroxide aqueous solution into the high-solid pretreatment material obtained in the step (1), stirring and extracting at room temperature, and carrying out solid-liquid separation to obtain lignin-rich lignin-dissolving reaction liquid and solid, wherein the solid is washed and dried to obtain enzymatic hydrolysis holocellulose residue which can be used for subsequent enzymolysis; (3) The lignin classification comprises the steps of dropwise adding an acidic regulator into the lignin-dissolving reaction liquid obtained in the step (2) until the system is just turbid and precipitated, obtaining the acidic lignin-dissolving reaction liquid, dropwise adding the acidic lignin-dissolving reaction liquid into an acidic aqueous solution, carrying out solid-liquid separation and purification to obtain a lignin-based photo-thermal conversion material, and then dropwise adding supernatant obtained through the solid-liquid separation into a reverse organic solvent, carrying out solid-liquid separation and purification to obtain the lignin-based anti-ultraviolet material.
  2. 2. The method according to claim 1, wherein the lignocellulosic feedstock in step (1) is a plant, forestry waste or processing waste having a particle size of 0.5-3.0 mm and containing at least cellulose and lignin.
  3. 3. The method according to claim 2, wherein the lignocellulosic feedstock is selected from more than one of pennisetum, miscanthus, wood chips, straw, bagasse, poplar, corn cobs.
  4. 4. The method according to claim 1, wherein the high solid state is achieved by means of press filtration, briquetting.
  5. 5. The method according to claim 1, wherein the basic catalyst is an inorganic base, an organic base or a strongly basic weak acid salt dissolved in an organic solution.
  6. 6. The method according to claim 5, wherein the basic catalyst is one or more selected from the group consisting of calcium hydroxide, sodium hydroxide, potassium hydroxide, ethylenediamine, triethylamine, ammonia water, sodium acetate, and disodium hydrogen phosphate.
  7. 7. The process according to claim 1, wherein 1-2 wt.% aqueous sodium hydroxide solution is added in step (2) in a volume of 10mL/g of high solids pretreatment material.
  8. 8. The method of claim 1, wherein the acidic regulator and the acidic aqueous solution in the step (3) are sulfuric acid, hydrochloric acid or phosphoric acid aqueous solutions with the acid content of 0.1-1 wt%, and the volume of the acidic aqueous solution is not less than 2 times of the volume of the acidulated lignin-dissolving reaction solution.
  9. 9. The method according to claim 1, wherein the reverse organic solvent is at least one selected from the group consisting of dimethyl carbonate, diethyl ether, dimethoxymethane, ethylene glycol dimethyl ether, acetone, ethanol, methyl acetate and isopropyl ether, and the volume of the reverse organic solvent is not less than 2 times the volume of the supernatant obtained by separation.

Description

Method for preparing lignin in-situ light functional material by lignocellulose pretreatment and synchronous classification Technical Field The invention relates to the technical field of biomass high-valued comprehensive utilization, in particular to a method for preparing lignin in-situ light functional materials by lignocellulose pretreatment and synchronous classification. Background The optical functional material plays a vital role in the fields of energy, environment, health and the like. For example, the photo-thermal conversion material can efficiently convert light energy into heat energy, and is the core of solar seawater desalination, photo-thermal treatment, deicing and other technologies. The ultraviolet resistant material is widely applied to sunscreens, coatings and polymer stabilizers to resist damage caused by ultraviolet radiation. Currently, the mainstream materials in the field depend on inorganic semiconductors, noble metals or fossil-based synthetic polymers, and there are general problems of high cost, large environmental footprint, poor biocompatibility or unsustainable sources, and the development of green substitutes derived from renewable resources is needed. Lignocellulose is the most abundant renewable resource on earth, and its efficient use is an important cornerstone for constructing sustainable society. Lignin is used as one of three main components, has a unique molecular structure of aromatic ring and conjugated functional group, and provides a basic framework for efficient broadband light absorption, so that the lignin becomes an ideal precursor for preparing light functional materials (anti-ultraviolet and photo-thermal conversion). However, traditional biomass utilization strategies generally follow a "separation followed by modification" pattern. In order to prepare functional lignin materials, lignin is often extracted from biomass by various methods (e.g., cooking, organic solvents, DES methods, etc.), and then given specific functions by chemical modification, high temperature carbonization, or compounding with other materials. The traditional mode has the defects that firstly, the process is lengthy and complex, a plurality of independent reaction units are involved, high energy consumption and high cost are caused, secondly, the natural active structure of the lignin is easy to be damaged or uncontrollable condensation reaction occurs in the lignin extraction process, the difficulty of subsequent functional modification is increased, and finally, the mode usually only focuses on a single component, and the high-value utilization of all components of cellulose, hemicellulose and lignin in lignocellulose is difficult to realize, so that resource waste is caused. Therefore, development of a new technical route is needed. Disclosure of Invention The invention aims to provide a method for synchronously preparing lignin in-situ light functional materials by lignocellulose pretreatment and classification, which solves the problems of complex process, high cost, incapability of synchronously realizing pretreatment and functionalization and the like in the prior art. The invention is realized by the following technical scheme: a method for preparing lignin in-situ light functional material by lignocellulose pretreatment and simultaneous classification, which comprises the following steps: (1) Uniformly mixing a pretreatment organic solution consisting of an alkaline catalyst, a solvating organic solvent and water with a lignocellulose raw material, stacking at room temperature for at least 3 days under a high solid state with a material liquid-solid ratio of not more than 3 mL/g, breaking chemical bonds among lignocellulose components, and in-situ solvation modification of disassembled lignin fragments to obtain a high-solid pretreatment material, wherein the concentration of the alkaline catalyst in the pretreatment organic solution is (0.005-0.05) g/mL, the volume ratio of the solvating organic solvent to water is (0.05-0.4) mL/mL, the solvating organic solvent is alcohol or aldehyde capable of carrying out solvation reaction with lignin, and solvent groups are grafted into lignin molecules, and the alcohol or aldehyde comprises one or more of triethylene glycol, phenoxyethanol, glycerol formal, dihydro-levoglucosone, tetrahydrofurfuryl alcohol, dimethyl isosorbide, phenethyl alcohol and the like; (2) Dissolving lignin, namely adding 1-2wt% of sodium hydroxide aqueous solution into the high-solid pretreatment material obtained in the step (1), stirring and extracting at room temperature to enable lignin components subjected to in-situ solvation modification to be fully dissolved in a liquid phase, and carrying out solid-liquid separation to obtain lignin-rich lignin-dissolving reaction liquid and solid, wherein the solid is washed and dried to obtain enzymatic hydrolysate residue (cellulose and hemicellulose) of comprehensive cellulose, which can be used for subsequent