CN111672472B

CN111672472B - Preparation method of degradable wood adsorption material

Info

Publication number: CN111672472B
Application number: CN202010582078.4A
Authority: CN
Inventors: 李玉柱; 罗屹东; 刘耀春; 彭湃
Original assignee: Foshan Southern China Institute For New Materials
Current assignee: Shuimu Shanhai Technology Foshan Co ltd
Priority date: 2020-06-23
Filing date: 2020-06-23
Publication date: 2022-05-27
Anticipated expiration: 2040-06-23
Also published as: CN111672472A

Abstract

The invention provides a preparation method of a degradable wood adsorption material, which comprises the steps of cutting, lignin removing, hemicellulose removing, cleaning, freeze drying and carbonizing treatment, the prepared wood adsorption material is stable in structure, good in rebound resilience, excellent in degradation performance, strong in adsorption force and environment-friendly, and the rebound resilience of the material is still kept above 95% after 10000 times of cyclic experiments (50% of compression ratio). Can effectively solve the problems that the preparation cost of the adsorption material in the prior art is high, the adsorption material is easy to be damaged by external force, the recovery cost is increased, the environmental pollution is easy to cause, and the adsorption effect is poor.

Description

Preparation method of degradable wood adsorption material

Technical Field

The invention relates to the field of preparation of adsorption materials, in particular to a preparation method of a degradable wood adsorption material.

Background

Currently, marine pollution is increasing, and among them, petroleum pollution is particularly serious. There are two main routes of petroleum pollution in the ocean: in marine transportation, a tanker crash causes some or all of the oil to flow into the ocean; oil leakage from offshore production platforms and pipelines. After the oil reaches the ocean, crustaceans and fishes in the polluted area die rapidly, seabirds are difficult to survive, and according to statistics, the number of seabirds dying from the oil pollution per year is hundreds of thousands, while crustaceans and fishes cannot be counted at all. In addition, the opaque oil film reduces the light permeability, so that the photosynthesis in the polluted sea area is seriously influenced, and the oxygen production of the ocean is reduced on one hand; on the other hand, algal overgrowth also affects and restricts the growth and reproduction of marine animals, thereby having a significant impact on the entire marine ecosystem. Aiming at petroleum pollution, the main method still adopts a fence to surround the petroleum on the surface of the sponge, so as to avoid large-area diffusion, and then a sewage disposal ship is used for collecting the petroleum, but a high-efficiency petroleum pollution adsorption method is not available at present, and synthetic polymer sponge such as polyurethane, polystyrene foaming materials and the like is adopted in the adsorbed materials, so that the materials have good oil absorption effect and good reusability, but have poor biodegradability; the gel material is adopted for adsorption, the preparation cost is high, the gel material is easy to damage by external force, the recovery cost is increased, the environmental pollution is easy to cause, and the material is not beneficial to recycling.

For example, patent No. CN109092260A discloses a petroleum adsorption degradation material and a preparation method thereof, wherein the material is a silica-carbon nanotube-kapok fiber derivative composite material loaded with titanium dioxide nanowires, but the adsorption effect in this scheme is poor, the preparation cost is high, and the degradability is poor.

In combination, in the field of preparation of the adsorption material, the development of the degradable, efficient, low-cost and reusable environment-friendly adsorption material has important significance.

Disclosure of Invention

The invention provides a preparation method of a degradable wood adsorbing material, which aims to solve the problems of poor degrading performance, unsatisfactory adsorbing effect and high preparation cost of the adsorbing material in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a degradable wood adsorption material comprises the following steps:

s1, cutting the collected wood as required;

s2, soaking the cut wood in a lignin removal solution;

s3, soaking the wood subjected to lignin removal in a hemicellulose removal liquid;

s4, cleaning the wood from which the hemicellulose is removed;

s5, drying the cleaned wood, and removing water in the wood;

and S6, carbonizing the dried wood to obtain the adsorbing material.

Optionally, the wood in step S1 is balsa and/or paulownia; the cut was 50 mm.

Optionally, in step S2, the mass percentage concentration of the lignin removal liquid is 3% to 20%, and the lignin removal liquid is hypochlorite and/or chlorite; the soaking temperature is room temperature, the soaking time is 8-72h, and the content of lignin needs to be detected by an HPLC method after soaking, so that the content of lignin after soaking is ensured to be less than 3%.

Optionally, in step S3, the hemicellulose removal liquid is a mixed solution of strong alkali liquor, sulfite and bisulfite, and the concentration of the strong alkali liquor is in the range of 1.0-5.0mol/L, and the concentration of the sulfite and bisulfite is in the range of 0.1-1.0 mol/L; the soaking temperature is 80-100 ℃, the soaking time is 2-8 h, and the content of hemicellulose is detected by an HPLC method after soaking, so that the content of hemicellulose after soaking is ensured to be less than 5%.

Optionally, in the step S4, the cleaning is performed by firstly using a weak acid aqueous solution under the ultrasonic-assisted condition, wherein the mass fraction of the weak acid is 5-50%, and the cleaning time is 20-60 min; and then cleaning for 3-5 times by using deionized water until the color of the deionized water is not changed.

Optionally, the drying in step S5 is freeze drying, and the freeze drying temperature is-50 ℃ and the freeze drying time is 8-24 h.

Optionally, the carbonization process in step S6 is: the wood is placed in a tube furnace, protective atmosphere is started, the temperature is raised from room temperature to 200-plus-300 ℃ at the temperature raising rate of 25-35 ℃/min, the temperature is maintained for 2-6h under the condition of 200-plus-300 ℃, then the temperature is raised to 900-plus-1100 ℃ at the temperature raising rate of 10-20 ℃/min, and the temperature is maintained for 2-6h at the temperature of 900-plus-1100 ℃.

Compared with the prior art, the invention has the beneficial technical effects that:

1. the invention adopts wood as the basic raw material, has the advantages of wide material source, simple process, easy preparation and strong operability, and is suitable for large-scale production.

2. According to the method, the wood is soaked by the lignin removal liquid and the hemicellulose removal liquid, so that the lignin content is effectively ensured to be less than 3%, the hemicellulose content is ensured to be less than 5%, a cellulose framework and a directional arrangement structure thereof are reserved, the wood is carbonized at high temperature, the freeze drying step is combined, the structure of the material is more stable, the wood adsorption material with good rebound resilience, excellent degradation performance and strong adsorption force is obtained, and the rebound resilience of the material is still kept to be more than 95% after 10000 times of cycle experiments (50% compression ratio).

3. The wood adsorption material prepared by the invention can adsorb various organic and/or inorganic materials, has the advantage of wide applicability, is environment-friendly in preparation process, is harmless to the environment in the use process, and accords with sustainable development.

Drawings

The invention will be further understood from the following description in conjunction with the accompanying drawings.

FIG. 1 is a graph showing the oil adsorption rate of an adsorbent prepared according to one embodiment of the present invention;

FIG. 2 is a SEM photograph of an adsorbent material prepared according to one embodiment of the present invention;

FIG. 3 is a graph showing the change in weight of wood before and after treatment with different solutions in accordance with one embodiment of the present invention;

FIG. 4 is a graph showing the petroleum adsorption rate of the adsorbent prepared in comparative example 1 according to the present invention;

FIG. 5 is a graph showing the petroleum adsorption rate of the adsorbent prepared in comparative example 2 according to the present invention;

FIG. 6 shows the petroleum adsorption rate of the material purchased in comparative example 3 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The invention relates to a preparation method of a degradable wood adsorption material, which is described in the following examples according to figures 1-6:

example 1:

s1, cutting the collected wood according to requirements;

s2, soaking the cut wood in a lignin removal solution;

s4, cleaning the wood from which the hemicellulose is removed;

s5, drying the cleaned wood, and removing water in the wood;

and S6, carbonizing the dried wood to obtain the adsorbing material.

The wood in the step S1 is balsa and/or paulownia, and balsa and/or paulownia are preferred as the test in this embodiment, because it has the advantages of wide raw material, easy preparation and good prepared product, but it does not limit the variety of wood used in the present invention; the cutting size is 50mm, in the embodiment, the wood is subjected to specification cutting, so that the portable and easy-to-operate adsorbing material can be prepared, and the adsorbing material can play the best adsorbing effect when being used; in the step S2, the mass percentage concentration of the lignin removal liquid is 3% -20%, and the lignin removal liquid is hypochlorite and/or chlorite; the soaking temperature is room temperature, the soaking time is 8-72h, and the content of lignin needs to be detected by an HPLC method after soaking, so that the content of lignin after soaking is ensured to be less than 3%; in the step S3, the hemicellulose removing liquid is a mixed solution of strong alkali liquid, sulfite and bisulfite, the concentration range of the strong alkali liquid is 1.0-5.0mol/L, and the concentration range of the sulfite and bisulfite is 0.1-1.0 mol/L; the soaking temperature is 80-100 ℃, the soaking time is 2-8 h, the content of hemicellulose is detected by an HPLC method after soaking, and the content of hemicellulose after soaking is ensured to be less than 5%; in the step S4, the cleaning is carried out by firstly adopting weak acid aqueous solution under the condition of ultrasonic assistance, wherein the mass fraction of weak acid is 5-50%, and the cleaning time is about 20-60 min; then, cleaning for 3-5 times by using deionized water until the color of the deionized water is not changed; in the step S5, the drying is freeze drying, the freeze drying temperature is-50 ℃, and the freeze drying time is 8-24 h; the carbonization process in step S6 is: the wood is placed in a tube furnace, protective atmosphere is started, the temperature is raised from room temperature to 200-plus-300 ℃ at the temperature raising rate of 25-35 ℃/min, the temperature is maintained for 2-6h under the condition of 200-plus-300 ℃, then the temperature is raised to 900-plus-1100 ℃ at the temperature raising rate of 10-20 ℃/min, and the temperature is maintained for 2-6h at the temperature of 900-plus-1100 ℃.

Example 2:

this example should be understood to include all the features of one of the previous examples and further optimize it on the basis thereof, in particular to provide a method for preparing a degradable wood adsorption material, comprising the following steps:

s1, cutting balsa into 50mm by 50mm samples;

s2, soaking the wood in a sodium hypochlorite aqueous solution with the concentration of 5% for 48 hours at room temperature, wherein the lignin content is 0.1% after soaking;

s3, soaking the whitened wood in a mixed solution of sodium hydroxide and sodium sulfite, wherein the concentration of the sodium hydroxide is 2.5mol/L, the concentration of the sodium sulfite is 0.4mol/L, the soaking temperature is 95 ℃, the soaking time is 5 hours, and the content of hemicellulose after soaking is 1.1%;

s4, in an ultrasonic cleaning machine, firstly cleaning the wood for 20min by using an acetic acid aqueous solution with the mass fraction of 5%, and then cleaning the wood by using deionized water for 60 min;

s5, freeze-drying the cleaned wood at-50 ℃ for 24 hours;

s6, putting the wood into a tube furnace, heating the temperature from room temperature to 260 ℃ at a heating rate of 25 ℃/min under the protection of argon atmosphere, preserving the heat for 3h, then heating to 1000 ℃ at a heating rate of 10 ℃/min, and preserving the heat for 6 h.

Example 3:

this example should be understood to include at least all of the features of any of the foregoing examples and further optimized on the basis thereof, and in particular provides a method for preparing a degradable wood adsorbent material, comprising the steps of:

s1, cutting the tung wood into samples of 50mm by 50 mm;

s2, soaking the wood in a 10% calcium hypochlorite aqueous solution at room temperature for 36h, wherein the lignin content is 0.6% after soaking;

s3, soaking the whitened wood in a mixed solution of potassium hydroxide and sodium sulfite, wherein the concentration of potassium hydroxide is 2.0mol/L, the concentration of sodium sulfite is 0.6mol/L, the soaking temperature is 85 ℃, the soaking time is 6 hours, and the content of hemicellulose after soaking is 1.3%;

s4, in an ultrasonic cleaning machine, cleaning the wood by using 20% acetic acid water solution for 30min, and then cleaning the wood by using deionized water for 30 min;

s5, freeze-drying the cleaned wood at-50 ℃ for 24 hours;

s6, putting the wood into a tube furnace, heating the temperature from room temperature to 200 ℃ at a heating rate of 35 ℃/min under the protection of nitrogen atmosphere, preserving the heat for 4h, then heating to 1050 ℃ at a heating rate of 10 ℃/min, and preserving the heat for 5 h.

Example 4:

s1, cutting balsa into 50mm by 50mm samples;

s2, soaking the wood in a sodium hypochlorite aqueous solution with the concentration of 10% for 30h at room temperature, wherein the lignin content is 0.5% after soaking;

s3, soaking the whitened wood in a mixed solution of potassium hydroxide and sodium bisulfite, wherein the concentration of potassium hydroxide is 2.0mol/L, the concentration of sodium sulfite is 0.6mol/L, the soaking temperature is 85 ℃, the soaking time is 6h, and the content of hemicellulose after soaking is 1.8%;

s5, freeze-drying the cleaned wood at-50 ℃ for 24 hours;

s6, placing the wood into a tube furnace, heating the temperature from room temperature to 250 ℃ at a heating rate of 30 ℃/min under the protection of nitrogen atmosphere, preserving the heat for 6h, then heating to 1000 ℃ at a heating rate of 10 ℃/min, and preserving the heat for 6 h.

In order to more clearly understand the effects of the adsorbent material prepared in the present application, the following comparative examples were also provided.

Comparative example 1:

the preparation method of an adsorbing material in the comparative example is as follows:

s1, cutting balsa into 50mm by 50mm samples;

s4, in an ultrasonic cleaning machine, cleaning the wood with 20% acetic acid water solution for 30min, and then cleaning the wood with deionized water for 30 min;

s5, freeze-drying the cleaned wood at-50 ℃ for 24 hours;

and S6, modifying the freeze-dried material to obtain the adsorbing material.

Comparative example 2:

the preparation method of the adsorbing material in the comparative example is as follows:

s1, cutting balsa into 50mm by 50mm samples;

s2, soaking the wood in a 25% sodium hypochlorite aqueous solution at room temperature for 30h, wherein the lignin content is 5% after soaking;

s3, soaking the whitened wood in a mixed solution of potassium hydroxide and sodium bisulfite, wherein the concentration of potassium hydroxide is 2.0mol/L, the concentration of sodium sulfite is 2.5mol/L, the soaking temperature is 95 ℃, the soaking time is 6h, and the content of hemicellulose after soaking is 15%;

s4, washing the wood with deionized water for 30 min;

s5, freeze-drying the cleaned wood at-50 ℃ for 24 hours;

s6, heating the freeze-dried material from room temperature to 150 ℃ at a heating rate of 10 ℃/min, washing and keeping the temperature for 2h at 150 ℃, then heating to 600 ℃ at a heating rate of 20 ℃/min, and keeping the temperature for 1h at 600 ℃ to obtain the adsorbing material.

Comparative example 3:

a degradable material allegedly having an oil-adsorbing effect was purchased in the market as comparative example 3.

The wood-based adsorbent materials prepared in examples 2 to 4, the adsorbent materials prepared in comparative examples 1 to 2, and the alleged degradation material purchased in comparative example 3 were subjected to degradation test analysis, and the results are shown in table 1.

TABLE 1

As can be seen from the data analysis in Table 1, the wood adsorbing material prepared by the method has excellent degradation performance, and the degradation performance of the wood adsorbing material is obviously superior to that of the material which is randomly purchased in the market and is declared to have degradability.

The wood-based adsorption materials prepared in examples 2 to 4, the adsorption materials prepared in comparative examples 1 to 2, and the allegedly degraded material purchased in comparative example 3 were subjected to compression test analysis (10000 cycles), and the results are shown in table 2.

TABLE 2

As can be seen from table 2, after 10000 cycles of experiments (50% compression ratio) of the wood adsorbing material prepared in the present application, the rebound resilience of the material is still maintained above 95%, while the difference between the comparative example 1 and the examples is that modification treatment is performed, the rebound resilience of the prepared adsorbing material is only 82.1%, the difference between the comparative example 2 and the implementation is that process parameters are changed, the rebound resilience of the prepared material is 76.4%, and the rebound resilience of the comparative example 3 is only 63.8, which indicates that the wood adsorbing material in the present application can obtain the material with the rebound resilience of 95% in the present application only in a complete process, and the overall stability ratio is excellent.

In addition, as can be seen from the analysis in fig. 1 and fig. 4 to 6, the adsorption rate of petroleum in the wood adsorbent prepared in the present application is significantly higher than that in comparative examples 1 to 3. The method shows that after high-temperature carbonization, the sample retains the laminated structure of the wood, and because lignin and hemicellulose are basically removed, an arch-shaped sponge structure is obtained instead of a latticed charcoal structure, so that the sample has good toughness and adsorbability, and the adsorption rate of the material can be effectively improved on the whole.

In combination, the wood adsorption material has strong adsorbability, is harmless to the environment and human body, and has wide application value.

The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims

1. The preparation method of the degradable wood adsorption material is characterized by comprising the following steps:

s1, cutting the collected wood according to requirements;

s2, soaking the cut wood in a lignin removal solution;

s4, cleaning the wood from which the hemicellulose is removed;

s5, drying the cleaned wood, and removing water in the wood;

s6, carbonizing the dried wood to obtain an adsorbing material;

wherein the drying in the step S5 is freeze drying, the freeze drying temperature is-50 ℃, and the freeze drying time is 8-24 h;

the carbonization process in step S6 is: the wood is placed in a tube furnace, protective atmosphere is started, the temperature is raised from room temperature to 200-plus-300 ℃ at the temperature raising rate of 25-35 ℃/min, the temperature is maintained for 2-6h under the condition of 200-plus-300 ℃, then the temperature is raised to 900-plus-1100 ℃ at the temperature raising rate of 10-20 ℃/min, and the temperature is maintained for 2-6h at the temperature of 900-plus-1100 ℃.

2. The method for preparing a degradable wood-based adsorbent material according to claim 1, wherein the wood in step S1 is balsa and/or paulownia; the cut was 50 mm.

3. The method for preparing a degradable wood-based adsorbent material according to claim 1, wherein the mass percentage concentration of the lignin removal solution in step S2 is 3% -20%, and the lignin removal solution is hypochlorite and/or chlorite.

4. The method for preparing a degradable wood-based adsorption material according to claim 1, wherein the hemicellulose removal liquid in step S3 is a mixed solution of strong alkali solution, sulfite and bisulfite, and the concentration of strong alkali solution is in the range of 1.0-5.0mol/L, and the concentration of sulfite and bisulfite is in the range of 0.1-1.0 mol/L.

5. The method for preparing a degradable wood-based adsorption material according to claim 1, wherein the cleaning in step S4 is performed by first cleaning with a weak acid aqueous solution under the ultrasonic-assisted condition, wherein the mass fraction of the weak acid is 5-50%, and the cleaning time is 20-60 min; and then cleaning for 3-5 times by using deionized water until the color of the deionized water is not changed.

6. The method for preparing the degradable wood adsorption material according to claim 3, wherein the soaking temperature is room temperature, the soaking time is 8-72h, and HPLC method is used for detecting the lignin content after soaking, so as to ensure that the lignin content after soaking is less than 3%.

7. The method for preparing a degradable wood adsorbing material according to claim 4, wherein the soaking temperature is 80-100 ℃, the soaking time is 2-8 h, and the content of hemicellulose is detected by HPLC after soaking, so that the content of hemicellulose after soaking is less than 5%.