CN115477785A - Preparation method of lignin/nano-cellulose aerogel - Google Patents
Preparation method of lignin/nano-cellulose aerogel Download PDFInfo
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- C08J2497/00—Characterised by the use of lignin-containing materials
- C08J2497/02—Lignocellulosic material, e.g. wood, straw or bagasse
Abstract
The invention provides a lignin/nano-cellulose aerogel and a preparation method and application thereof, belonging to the technical field of environment-friendly materials. The invention takes industrial lignin with wide source and nano-cellulose with excellent compatibility in the paper industry as precursors to prepare the lignin/nano-cellulose aerogel with hydrophobic property. After the lignin and the nanocellulose are fully crosslinked by adding the crosslinking agent, the porous aerogel is prepared by adopting a freeze-drying technology, and then the aerogel is subjected to hydrophobic modification to obtain a lignin/nanocellulose aerogel sample with hydrophobic property. The aerogel product prepared by the method is green and environment-friendly, has biodegradability and biocompatibility, is simple in industrial preparation process, is easy to produce in an enlarged manner, and has remarkable ecological and environment-friendly benefits. The development of the aerogel further expands the huge potential of the lignin/nano-cellulose aerogel in the field of oil-water separation, and has important significance for high-value utilization of lignin.
Description
Technical Field
The invention relates to the technical field of environment-friendly materials, in particular to a preparation method of lignin/nano-cellulose aerogel.
Background
With the rapid development of world economy and the continuous improvement of human life quality, the demand of human beings for oil increases, and the problem of environmental pollution caused by oil leakage in the processes of obtaining oil and transporting is accompanied, so that the marine ecosystem, water resources and even human health and safety are seriously threatened. Meanwhile, the environment pollution situation of the industrial wastewater containing oily sewage or non-polar organic solvent in China is not optimistic. Therefore, the problem of water quality pollution of oily sewage and industrial wastewater is effectively solved.
The traditional method for recovering petroleum has poor effect on separating oil drops and oil-water emulsion. Researchers have used composite materials such as hydrophobic and oleophilic adsorption materials, bioremediation materials, membrane materials, curing agents and the like to separate the organic pollutants from water, and have recycled the organic pollutants through the prior art. The cellulose-based aerogel is a solid with a three-dimensional porous network structure with porous interconnection and branched nanometer, and has remarkable advantages in the fields of adsorption materials, building materials, bionic matrixes, oil-water separation and the like due to the characteristics of high porosity, light weight and the like.
In recent years, the only animal cellulose in nature, ascidian nanocellulose (TCNCs), has attracted considerable attention for its unique properties. The nano cellulose generated by the sea squirt tunic has wider length distribution, is between 500nm and 2 mu m, has the length-diameter ratio of more than 75, has the excellent characteristics of Young modulus as high as 143GPa, high crystallinity, porosity of more than 99 percent and the like, has the advantages of clean components, natural reproducibility, no toxicity, biodegradability and the like, and is a potential raw material for preparing medical bionic materials, optical materials, reinforced composite materials, template materials and biosensors.
The invention takes nano-cellulose as a basic skeleton, takes lignin as a filler, adds a cross-linking agent for full cross-linking, and adopts a freeze-drying technology to prepare the lignin/nano-cellulose aerogel. And then the aerogel sample is subjected to hydrophobic modification, so that the hydrophobic modified aerogel sample is proved to have good oil-water separation capacity and recycling availability.
The aerogel product prepared by the invention is green and environment-friendly, has biodegradability and biocompatibility, is simple in process preparation flow, is easy to produce in an enlarged mode, and has remarkable ecological and environment-friendly benefits. The development of the aerogel further expands the huge potential of the lignin/nano-cellulose aerogel in the field of oil-water separation, and has important significance on high-value utilization of lignin.
Disclosure of Invention
The invention aims to solve the technical problem of providing a preparation method of lignin/nano cellulose aerogel.
The invention is realized by the following steps:
the invention firstly provides a preparation method of lignin/nano-cellulose aerogel, which comprises the steps of taking nano-cellulose as a basic skeleton, taking lignin as a filler, adding a cross-linking agent for full cross-linking, preparing the lignin/nano-cellulose aerogel by adopting a freeze drying technology, then soaking the lignin/nano-cellulose aerogel in an electronic fluorinated liquid (such as AK-225) containing dopa as a hydrophobic material for hydrophobic modification, and finally standing at normal temperature to completely volatilize an organic solvent so as to obtain an aerogel product with hydrophobic property.
The method specifically comprises the following steps:
(1) Mixing alkali lignin and nano cellulose, and uniformly dispersing in deionized water;
(2) Adding a cross-linking agent into the mixture obtained in the step (1) and stirring to completely cross-link the lignin and the nano-cellulose to obtain a lignin/nano-cellulose mixture;
(3) Freeze-drying the lignin/nanocellulose mixture obtained in the step (2) to obtain a lignin/nanocellulose aerogel sample;
(4) Performing hydrophobic modification on the aerogel sample obtained in the step (3): firstly, putting a dopa monomer into a synthesis tube, adding N-N-Dimethylformamide (DMF) solvent into the synthesis tube to dissolve the dopa monomer, then weighing a certain amount of initiator Azobisisobutyronitrile (AIBN) and adding the initiator into the synthesis tube, and finally adding perfluorooctyl ethyl acrylate (PFOE) into the synthesis tube. Repeated freezing-vacuumizing-unfreezing cycles are performed to remove oxygen in the synthesis tube and fill high-purity N 2 Protecting Dopamine (DOPAM) from being oxidized by oxygen in the air. Then reacted for 24h at 70 ℃ under an oil bath. And after the reaction is finished, dissolving the reactant in the electronic fluorination solution firstly to remove impurities by filtration, dripping the solution into methanol to generate white precipitate, and drying the precipitate in a vacuum drying oven for 24 hours to obtain the fluorine-containing dopa copolymer.
Secondly, according to the influence of different fluorine contents on the surface energy of the fluorine-containing dopa copolymer, the hydrophobic property of the material is further influenced, and the fluorine-containing dopa polymers with different fluorine contents are prepared. The relative content of fluorine in the copolymer is measured by ion chromatography, and the content of fluorine is determined according to the size of a contact angle. And finally, dispersing the fluorine-containing dopa copolymer by taking the electronic fluorinated liquid as an organic solvent, wherein the weight ratio of the fluorine-containing dopa copolymer is as follows: electron fluorination liquid =1:50 to prepare an electronic fluorinated liquid containing the dopa copolymer as a hydrophobic material; and soaking the obtained aerogel sample in the hydrophobic material, then placing the aerogel sample in a normal-temperature environment, and obtaining the lignin/nano-cellulose aerogel sample with hydrophobic performance after the organic solvent of the electronic fluorination liquid is completely volatilized.
Further, the method comprises the following steps:
the nano-cellulose in the step (1) is one of bacterial nano-cellulose and TCNCs.
The lignin in the step (1) is one of alkali lignin, enzymatic hydrolysis lignin, lignosulfonate and lignin carboxylate.
The mass ratio of the lignin to the nanocellulose in the step (1) is preferably 1:3 to 1:1.
the cross-linking agent in the step (2) is polyethylene glycol diglycidyl ether PEGDGE.
The addition amount of the cross-linking agent in the step (2) is 1/2-1/3 (volume amount) of the addition amount of the alkali lignin.
And (3) adding a cross-linking agent into the mixture obtained in the step (2), and stirring at 45-75 ℃ for 1-4 h.
And (4) the electronic fluorination liquid is AK-225.
The specific preparation method of the fluorine-containing dopa copolymer in the step (4) is as follows: firstly, accurately weighing 10g of borax (Na) in sequence 2 B 4 O 7 ·10H 2 O) and 4g NaHCO 3 And 100ml of deionized water was added to a 250ml beaker for uniform dissolution, 5g of dopa hydrochloride monomer (DOPAM-HCl) was added to the beaker, 4.7ml of methacrylic anhydride and 25ml of Tetrahydrofuran (THF) were thoroughly mixed and added to the solution, 1M NaOH was added dropwise to the beaker solution prepared so that the pH of the solution =8, and finally the solution was allowed to bubble overnight for reaction. And (3) carrying out suction filtration on the dopa crude product obtained by the reaction by using a suction bottle to remove borax, standing and layering the dopa crude product, collecting a lower solution, adding 50ml of ethyl acetate into the lower solution, fully shaking the lower solution uniformly, standing and layering the dopa crude product, collecting the lower solution, and adding the prepared 6M HCl solution to make the pH of the lower solution less than 2. 50ml of ethyl acetate (C) were then added 4 H 8 O 2 ) Extracting, collecting the upper layer solution, extracting the lower clear solution twice with 50ml ethyl acetate, collecting the upper layer solution for each extraction, and adding anhydrous magnesium sulfate (MgSO) 4 ) And sealing and standing for 12 hours, and performing suction filtration to remove anhydrous magnesium sulfate solids. The resulting solution was rotary-evaporated to 25ml at room temperature, and 225ml of n-hexane (C) was added 6 H 14 ) Lightly shaking by handAnd then putting the dopa monomer into a refrigerator at 4 ℃ for recrystallization for 12 hours, and then transferring the dopa monomer into a vacuum drying oven at 45 ℃ for drying for 12 hours to fully remove n-hexane in the solution, so that the high-purity dopa monomer is obtained. Then 0.1g of the synthesized dopa monomer is weighed and put into a synthesis tube, 2ml of N-N-Dimethylformamide (DMF) solvent is added into the synthesis tube to dissolve the dopa monomer, a certain amount of initiator Azobisisobutyronitrile (AIBN) is weighed and added into the synthesis tube, and finally perfluorooctyl ethyl acrylate (PFOE) is added into the synthesis tube. Repeated freezing-vacuumizing-unfreezing cycles are performed to remove oxygen in the synthesis tube and fill high-purity N 2 Protecting Dopamine (DOPAM) from being oxidized by oxygen in the air. The reaction was then carried out at 70 ℃ under an oil bath for 24h. And after the reaction is finished, dissolving the reactant in the electronic fluorination liquid, filtering to remove impurities, dripping the solution into methanol to generate white precipitate, and drying in a vacuum drying oven for 24 hours to obtain the fluorine-containing dopa copolymer.
Secondly, the invention also provides the lignin/nano-cellulose aerogel prepared by the preparation method.
Finally, the invention provides the use of said lignin/nanocellulose aerogel in oil-water separation.
The invention has the following advantages: the invention takes industrial lignin with wide source and nano-cellulose with excellent biocompatibility in the paper industry as precursors to prepare the lignin/nano-cellulose aerogel with hydrophobic property. After the lignin and the nanocellulose are fully crosslinked by adding the crosslinking agent, the porous aerogel is prepared by adopting a freeze-drying technology, and then the aerogel is subjected to hydrophobic modification to obtain a lignin/nanocellulose aerogel sample with hydrophobic property.
The method has the advantages of simple and convenient process flow, easy amplification production, low cost, complete material framework structure, and obvious low-carbon energy and environmental protection benefits. The prepared lignin/nano cellulose aerogel has a developed hierarchical pore structure, high porosity, good oil-water separation capacity and cyclic availability, shows an excellent separation effect on oil-containing wastewater, oil drops and emulsion oil-water separation treatment, has excellent recycling performance, further expands the amplified application of the porous aerogel in the small oil-water separation fields of difficult-to-separate oil drops, emulsion and the like, is expected to further realize green, low-carbon, environment-friendly, low-cost and recycling industrial production in the future, and accords with the 'double-carbon' policy under the existing policy.
Drawings
The invention will be further described with reference to the following examples and figures.
Fig. 1 is an internal structural analysis of aerogels composed of TCNCs and lignin in different proportions: (C, C-1, C-2) schematic macroscopic and microscopic structural representation of aerogels prepared from pure TCNCs; (A1, A1-1, A1-2) macroscopic and microscopic schematic views of sample A1; (A2, A2-1, A2-2) macroscopic and microscopic representations of sample A2; (A3, A3-1, A3-2) macroscopic and microscopic schematic of sample A3.
Figure 2 is a performance display of aerogel A2: testing the water contact angle of the aerogel (a); aerogel hydrophobicity test (b); oil-water separation experiment of aerogel and observation of the amount of oil droplets in the liquid before and after treatment under an optical microscope (c).
Fig. 3 shows the separation efficiency of four substances filtered 10 times.
Detailed Description
Comparative example 1
(1) Dispersing pure TCNCs into 10ml of deionized water, stirring the mixture for 12 hours by a magnetic stirrer at normal temperature, and then carrying out ultrasonic oscillation on the stirred mixture by an ultrasonic cleaner to ensure that the mixture is uniformly dispersed;
(2) Adding 1.5ml of a cross-linking agent PEGDGE, and continuously stirring for 1h at 45 ℃ to completely cross-link lignin and nano-cellulose to obtain a lignin/nano-cellulose mixture;
(3) Preparing a lignin/nano cellulose aerogel sample by freeze drying;
(4) Performing hydrophobic modification on the aerogel sample obtained in the step (3): firstly, accurately weighing 10g of borax (Na) in sequence 2 B 4 O 7 ·10H 2 O) and 4g NaHCO 3 Adding 100ml deionized water into 250ml beaker, dissolving uniformly, adding 5g saltAcid dopa monomer (DOPAM-HCl) was added to the solution after thoroughly mixing 4.7ml of methacrylic anhydride and 25ml of Tetrahydrofuran (THF) in a beaker, the pH of the solution was adjusted to =8 by adding 1M NaOH drop wise to the beaker solution, and finally allowed to bubble overnight. And (3) carrying out suction filtration on the dopa crude product obtained by the reaction by using a suction bottle to remove borax, standing and layering the dopa crude product, collecting a lower solution, adding 50ml of ethyl acetate into the lower solution, fully shaking the lower solution uniformly, standing and layering the dopa crude product, collecting the lower solution, and adding the prepared 6M HCl solution to make the pH of the lower solution less than 2. 50ml of ethyl acetate (C) were then added 4 H 8 O 2 ) Extracting, collecting the upper layer solution, extracting the lower clear solution twice with 50ml ethyl acetate, collecting the upper layer solution for each extraction, and adding anhydrous magnesium sulfate (MgSO) 4 ) And sealing and standing for 12 hours, and performing suction filtration to remove anhydrous magnesium sulfate solid. The resulting solution was rotary-evaporated to 25ml at room temperature, and 225ml of n-hexane (C) was added 6 H 14 ) After being slightly shaken by hands, the solution is placed in a refrigerator at 4 ℃ for recrystallization for 12 hours, and then the solution is transferred to a vacuum drying oven at 45 ℃ for drying for 12 hours, so that n-hexane in the solution is sufficiently removed, and the high-purity dopa monomer is obtained. Then weighing 0.1g of the synthesized dopa monomer, putting the dopa monomer into a synthesis tube, adding 2ml of N-N-Dimethylformamide (DMF) solvent into the synthesis tube to dissolve the dopa monomer, weighing a certain amount of initiator Azobisisobutyronitrile (AIBN), adding the initiator Azobisisobutyronitrile (AIBN) into the synthesis tube, and finally adding perfluorooctyl ethyl acrylate (PFOEA) into the synthesis tube. Repeated freezing-vacuumizing-unfreezing cycles are performed to remove oxygen in the synthesis tube and fill high-purity N 2 Protecting Dopamine (DOPAM) from being oxidized by oxygen in the air. Then reacted for 24h at 70 ℃ under an oil bath. And after the reaction is finished, dissolving the reactant in the electronic fluorination solution firstly to remove impurities by filtration, dripping the solution into methanol to generate white precipitate, and drying in a vacuum drying oven for 24 hours to obtain the fluorine-containing dopa copolymer.
Secondly, according to the influence of different fluorine contents on the surface energy of the fluorine-containing dopa copolymer, the hydrophobic property of the material is further influenced. Preparing the fluorine-containing dopa polymer with different fluorine contents, measuring the relative fluorine content in the copolymer by using ion chromatography, determining the fluorine content according to the contact angle, and when the fluorine content is 33.6%, optimizing the hydrophobic property.
And finally, dispersing the fluorine-containing dopa copolymer by taking the electronic fluorinated liquid as an organic solvent, wherein the weight ratio of the fluorine-containing dopa copolymer is as follows: electron fluorination liquid =1:50 to prepare an electronic fluorinated liquid containing the dopa copolymer as a hydrophobic material; and soaking the obtained aerogel sample in the hydrophobic material, then placing the aerogel sample in a normal-temperature environment for 20min, and obtaining a lignin/nano-cellulose aerogel sample C with hydrophobic performance after the organic solvent of the electronic fluorination liquid is completely volatilized.
Example 2
(1) Mixing alkali lignin and ascidian nanocellulose (TCNCs) according to a mass ratio of 1:3, dispersing the mixture into 10ml of deionized water, stirring the mixture for 12 hours by a magnetic stirrer at normal temperature, and then carrying out ultrasonic oscillation on the stirred mixture by an ultrasonic cleaner to ensure that the mixture is uniformly dispersed;
(2) Adding 1.75ml (about half of the volume of the alkali lignin) of a crosslinking agent PEGDGE, and continuously stirring at 55 ℃ for 2h to completely crosslink the lignin and the nanocellulose to obtain a lignin/nanocellulose mixture;
(3) Preparing a lignin/nano-cellulose aerogel sample by freeze drying;
(4) Performing hydrophobic modification on the aerogel sample obtained in the step (3): a fluorodopa copolymer (same as comparative example 1) was prepared and the ratio of fluorodopa polymer: electron fluorination liquid =1:50 to prepare an electronic fluorinated liquid containing the dopa copolymer as a hydrophobic material; and soaking the obtained aerogel sample in the hydrophobic material, then placing the aerogel sample in a normal-temperature environment for 25min, and obtaining a lignin/nano-cellulose aerogel sample A1 with hydrophobic property after the organic solvent of the electronic fluorination liquid is completely volatilized.
Example 3
(1) Mixing alkali lignin and nano cellulose according to the weight ratio of 1:1, dispersing the mixture into 10ml of deionized water after mixing, stirring the mixture for 12 hours by a magnetic stirrer at normal temperature, and then carrying out ultrasonic vibration on the stirred mixture by an ultrasonic cleaner;
(2) Adding 2.0ml of a cross-linking agent PEGDGE, and continuously stirring for 3 hours at 65 ℃ to completely cross-link lignin and nanocellulose to obtain a lignin/nanocellulose mixture;
(3) Performing freeze drying to obtain a lignin/nano-cellulose aerogel sample;
(4) Performing hydrophobic modification on the aerogel sample obtained in the step (3): a fluorodopa copolymer (same as comparative example 1) was prepared and the ratio of fluorodopa polymer: electron fluorination liquid =1: preparing electronic fluorinated liquid containing the dopa copolymer as a hydrophobic material according to the mass ratio of 50; and soaking the obtained aerogel sample in the hydrophobic material, then placing the aerogel sample in a normal-temperature environment for 30min, and obtaining a lignin/nano-cellulose aerogel sample A2 with hydrophobic property after the organic solvent of the electronic fluorination liquid is completely volatilized.
(5) And (3) carrying out an oil-water separation test on the oil emulsion mixture (the volume ratios of chloroform/water, n-heptane/water, benzene/water and cyclohexane/water are all 1) of the sample A2 in the step (4) by an oil-water separation device.
Example 4
(1) Mixing alkali lignin and nano cellulose according to the ratio of 3:1, dispersing the mixture into 10ml of deionized water after mixing, stirring the mixture for 12 hours by a magnetic stirrer at normal temperature, and then carrying out ultrasonic vibration on the stirred mixture by an ultrasonic cleaner;
(2) Adding 2.25ml of a cross-linking agent PEGDGE, and continuously stirring for 4 hours at 75 ℃ to completely cross-link lignin and nano-cellulose to prepare a lignin/nano-cellulose mixture;
(3) Performing freeze drying to obtain a lignin/nano-cellulose aerogel sample;
(4) Performing hydrophobic modification on the aerogel sample obtained in the step (3): a fluorodopa copolymer (same as comparative example 1) was prepared and the ratio of fluorodopa polymer: electron fluorination liquid =1: preparing electronic fluorinated liquid containing the dopa copolymer as a hydrophobic material according to the mass ratio of 50; and soaking the obtained aerogel sample in the hydrophobic material, then placing the aerogel sample in a normal-temperature environment for 35min, and obtaining a lignin/nano-cellulose aerogel sample A3 with hydrophobic property after the organic solvent of the electronic fluorination liquid is completely volatilized.
Example 5
Physical characterization of the sample is carried out by adopting a scanning electron microscope (figure 1), aerogel samples (C, A1, A2 and A3) prepared by lignin and TCNCs in different proportions are measured, and a macro microstructure morphology test is carried out on the aerogel samples. As can be seen from C, C-1, C-2, the microscopic morphology of the aerogel consisting of pure TCNCs is relatively disordered and does not form a significant lamellar structure. The combination of the fibers is disordered and irregular. While the aerogel containing lignin of A1, A2 and A3 has a regular layered structure. Wherein the layered structure is not evident in A1, A3 and A2. Particularly, A3, due to the increase of the lignin content, the skeleton formed by TCNCs is reduced, so that a honeycomb-like structure is formed in the aerogel, and the structure cannot improve the elastic property of the aerogel. Compared with A1 and A2, the laminated structure is obvious. Wherein, TCNCs form the inner skeleton of the aerogel, and lignin plays a filling role, and the cellulose skeletons become pillars for supporting each layer of skeletons and play a spring-like role. Compared with A1, the content of TCNCs in A2 is greatly reduced, so that the preparation cost of the aerogel is undoubtedly greatly reduced, the layered structure is clearer, and the elasticity of the aerogel is further improved.
Example 6
5ml of distilled water was mixed with 5ml of chloroform, n-heptane, benzene and cyclohexane to prepare a mixture of four oil emulsions of chloroform/water, n-heptane/water, benzene/water and cyclohexane/water, and 0.01ml of Tween 80 was added as a surfactant to mix them uniformly. The contact angle of the surface of the aerogel sample A2 is tested by using a contact angle analysis measuring instrument, an experimental iron stand is used as a support, a three-jaw clamp is used for clamping the upper part of a disposable injector, and a measuring cylinder is placed below the injector and used for collecting small liquid drops, so that an oil-water separation device is assembled to perform an oil-water separation test (shown in figure 2). As shown in fig. 2 (a), after the measurement of the aerogel sample, the water contact angle of the surface of the aerogel can reach 140 °, which reaches the general hydrophobic standard. As can be seen from fig. 2 (b), when a drop of water is dropped on the surface of the aerogel using a dropper, the drop of water stays on the surface of the aerogel completely, and the interface is clearly visible. The aerogel has hydrophobic properties. To test the oil-water separation performance of the aerogel, the aerogel was cut into an appropriate shape (diameter =1.5 ± 0.1cm, height =1.8 ± 0.1 cm) and placed at the bottom of a 5ml disposable syringe, the oil-water separation test was performed by a gravity separation method by pouring the oil emulsion mixture into the syringe, and then the separated droplets were squeezed into a measuring cylinder below, and the number of oil droplets in the liquid before and after the treatment was observed under an optical microscope, thereby testing the oil-water separation ability of the sample. From fig. 2 (c), it can be found that the oil droplets before separation are completely distributed in the water, and after separation, the oil droplets are completely disappeared, which can prove that the aerogel has very excellent oil-water separation ability. And according to the mechanical property and the high elasticity of the aerogel, after oil drops are absorbed, a mechanical extrusion mode can be adopted to recover the sample. Compared with other oil-water separation materials, the material has the greatest advantages of low cost and recycling.
Example 7
Chloroform (Chloroform), N-heptane (N-heptane), benzene (BTX), cyclohexane (CYH) were mixed with distilled water at a ratio of 1:1 are prepared into oil emulsion mixtures respectively, and 0.01ml of Tween 80 is added as a surfactant. An experimental iron stand is used as a support, the upper part of a disposable injector is clamped by three clamping claws, a measuring cylinder is arranged below the injector and used for collecting small liquid drops, so that the oil-water separation device is assembled, and the oil-water separation and recycling efficiency of A2 is tested (shown in figure 3). As shown in the attached figure 3, the oil-water separation and recycling efficiency tests of the mixture of four oil emulsions, namely chloroform/water, n-heptane/water, benzene/water and cyclohexane/water, show that after the surfactant is stabilized and the oil emulsion is separated, the aerogel is washed by ethanol, and the oil-water separation efficiency is always kept above 90% after the aerogel is repeatedly used for 10 times, which shows that the aerogel sample shows good recycling efficiency and high oil-water separation efficiency in the oil-water separation process, and has wide application prospects in the field of oil-water separation.
While specific embodiments of the invention have been described, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, as equivalent modifications and variations as will be made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the appended claims.
Claims (10)
1. A preparation method of lignin/nano-cellulose aerogel is characterized by comprising the following steps: the method comprises the following steps:
(1) Mixing lignin and nano-cellulose, and uniformly dispersing in deionized water;
(2) Adding a cross-linking agent into the mixture obtained in the step (1) and stirring to completely cross-link the lignin and the nanocellulose to obtain a lignin/nanocellulose mixture;
(3) Freezing and drying the lignin/nano-cellulose mixture in the step (2) to prepare a lignin/nano-cellulose aerogel sample;
(4) Performing hydrophobic modification on the aerogel sample obtained in the step (3): preparing a dopa monomer through an amidation reaction, synthesizing a fluorine-containing dopa copolymer by using a free radical copolymerization method, and finally preparing an electronic fluorinated liquid of the fluorine-containing dopa copolymer as a hydrophobic material; and soaking the obtained aerogel sample in the hydrophobic material, then placing the aerogel sample in a normal-temperature environment, and obtaining a lignin/nano-cellulose aerogel sample with hydrophobic property after the organic solvent of the electronic fluorination liquid is completely volatilized.
2. The method for preparing lignin/nanocellulose aerogel according to claim 1, characterized by:
the nano-cellulose in the step (1) is preferably one of bacterial nano-cellulose and TCNCs.
3. The method for preparing lignin/nanocellulose aerogel according to claim 1, characterized in that:
the lignin in the step (1) is one of alkali lignin, enzymatic hydrolysis lignin, lignosulfonate and lignin carboxylate.
4. The method for preparing lignin/nanocellulose aerogel according to claim 1, characterized in that:
the mass ratio of the lignin to the nanocellulose in the step (1) is 1:3 to 1:1.
5. the method for preparing lignin/nanocellulose aerogel according to claim 1, characterized in that:
the cross-linking agent in the step (2) is polyethylene glycol diglycidyl ether PEGDGE.
6. The method for preparing lignin/nanocellulose aerogel according to claim 1, characterized in that:
and (3) adding a cross-linking agent into the mixture obtained in the step (2), and stirring at 45-75 ℃ for 1-4 h.
7. The method for preparing lignin/nanocellulose aerogel according to claim 1, characterized in that:
and (4) the electronic fluorination liquid is AK-225.
8. The method for preparing lignin/nanocellulose aerogel according to claim 1, characterized by:
the specific preparation method of the fluorine-containing dopa copolymer in the step (4) is as follows:
A. preparing a dopa monomer;
B. and synthesizing the fluorine-containing dopa copolymer by taking azobisisobutyronitrile as an initiator and using perfluorooctyl ethyl acrylate and a dopa monomer.
9. A lignin/nanocellulose aerogel produced by the method of any one of claims 1 to 8.
10. Use of the lignin/nanocellulose aerogel according to claim 9 in oil-water separation.
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|---|---|---|---|---|
| CN116606481B (en) * | 2023-05-04 | 2023-11-28 | 安徽省安瑞机电科技有限公司 | Thermal insulation aerogel composite and its use in sensor housings |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160168363A1 (en) * | 2014-06-27 | 2016-06-16 | Api Intellectual Property Holdings, Llc | Nanocellulose-polymer composites, and processes for producing them |
| CN109054101A (en) * | 2018-07-06 | 2018-12-21 | 福建农林大学 | A kind of super-hydrophobic magnetic Nano cellulose and preparation method thereof |
| CN112480464A (en) * | 2020-11-19 | 2021-03-12 | 华南理工大学 | Hydrophobic lignin/cellulose aerogel oil-water separation material and preparation method and application thereof |
-
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- 2022-08-23 CN CN202211017246.0A patent/CN115477785A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160168363A1 (en) * | 2014-06-27 | 2016-06-16 | Api Intellectual Property Holdings, Llc | Nanocellulose-polymer composites, and processes for producing them |
| CN109054101A (en) * | 2018-07-06 | 2018-12-21 | 福建农林大学 | A kind of super-hydrophobic magnetic Nano cellulose and preparation method thereof |
| CN112480464A (en) * | 2020-11-19 | 2021-03-12 | 华南理工大学 | Hydrophobic lignin/cellulose aerogel oil-water separation material and preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| 宁登文: ""海鞘纳米纤维素气凝胶的制备及其性能研究"", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》, pages 016 - 2297 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116606481B (en) * | 2023-05-04 | 2023-11-28 | 安徽省安瑞机电科技有限公司 | Thermal insulation aerogel composite and its use in sensor housings |
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