Preparation method of one-dimensional nano titanium dioxide in-situ composite biochar catalytic material
By in situ composite biomass with titanium dioxide in an alkaline hydrothermal environment, a one-dimensional nano titanium dioxide/biochar composite material is solved, and the problem of difficult degradation of antibiotic pollution is achieved is achieved efficient antibiotic degradation and material stability is improved.
Patent Information
- Application Number
- CN202510289394.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-12
- Publication Date
- 2025-06-13
AI Technical Summary
In the prior art, when dealing with antibiotic contamination, it is difficult to effectively degrade difficult-to-degrade antibiotic contaminants, and one-dimensional nanotitanium dioxide is prone to agglomeration in application, affecting its uniform dispersion and compatibility in matrix materials.
Through hydrothermal reaction in an alkaline environment, biomass and titanium dioxide are compounded in situ to form a one-dimensional nanotitanium dioxide/biochar composite material. This method not only improves the specific surface area and number of active sites of the material, but also improves the crystal structure through secondary pyrolysis technology and enhances the stability of the material.
The efficient degradation of antibiotics is achieved, and the degradation efficiency of pollutants is significantly improved through adsorption-catalytic synergistic cycle and electron transfer synergistic action, while enhancing the structural stability and photocatalytic performance of the material.
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Figure CN120132823A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a preparation method of a one-dimensional nano titanium dioxide in-situ composite biochar catalytic material, belonging to the technical field of functional materials and their preparation. Background Art
[0002] In recent years, the pollution of pharmaceutical compounds has posed a great threat to the sustainable development of the environment and human health. With the extensive use of antibiotics, antibiotics have been detected in surface water, groundwater, sediment, soil and livestock manure. Although the concentration of antibiotics in the water environment is very low, different from other pharmaceutical compound pollutants, antibiotics have strong biological effects on microorganisms, and most antibiotics are persistent pollutants that are difficult to degrade. Therefore, it is urgent to find an effective method to treat antibiotic pollution, and the effective degradation and mineralization of antibiotic pollutants have become a research hotspot in the field of water treatment.
[0003] Advanced oxidation technologies can directly mineralize antibiotics or generate a large number of strongly oxidizing free radicals to improve their biodegradability. Some commonly used advanced oxidation technologies for removing antibiotic pollution include photocatalysis, persulfate oxidation, ozonation and Fenton oxidation. Advanced oxidation processes (AOPs) are an important part of environmental pollution treatment technologies. By using AOPs processes, various strongly oxidizing reactive oxygen species (ROS) can be generated, such as hydroxyl radicals (·OH), sulfate radicals (SO 4 - ·) and singlet oxygen ( 1 O 2 ) etc., which can completely mineralize and remove organic pollutants.
[0004] In practical applications, one-dimensional nano titanium dioxide can also achieve the synergistic effect of photocatalysis and PMS (peroxymonosulfate) activation. The photo-generated electrons produced by light irradiation can not only directly participate in the reduction reaction of organic pollutants, but also promote the activation of PMS to generate more free radicals. At the same time, the free radicals generated by PMS activation can also synergistically act with the free radicals generated in the photocatalysis process to further improve the degradation effect on organic pollutants. This synergistic effect makes one-dimensional nano titanium dioxide have greater application potential in the treatment of refractory organic pollutants. Due to its high specific surface area and surface energy, one-dimensional nano titanium dioxide is prone to agglomeration, resulting in difficulty in being uniformly dispersed in the matrix material in practical applications. At the same time, when compounding with other materials, there may be problems with the compatibility with the matrix material, affecting the overall performance of the composite material.
[0005] In the present invention, under the high temperature, high pressure and alkaline environment of the hydrothermal reaction, new chemical bonds or coordination bonds may be formed between the biomass and the ions in the alkaline solution. Such chemical bonds can significantly change the electron cloud distribution and charge transport characteristics of the composite material, thereby endowing the material with unique electrical and optical properties. New binding modes can be formed between the polar functional groups generated on the biomass surface and the active sites on the surface of the one-dimensional nanostructure through interactions such as hydrogen bonds and chemical bonds. This interaction may not only promote the generation of new species with special activities in the system, but also endow these species with unique electronic structures and chemical activities. At the same time, the binding of polar functional groups to active sites can enhance the interfacial force between titanium dioxide and biomass, thereby improving the stability of the composite material.
[0006] Therefore, the present invention prepares a one-dimensional nano-titanium dioxide / biochar composite material that can be used for activating PMS, photocatalysis, and PMS-photocatalysis synergistic action. The adsorption of biochar enriches the antibiotics on the catalyst surface, making it easier for free radicals to come into contact with and react with antibiotic molecules. At the same time, the free radicals generated by photocatalysis and PMS activation can timely degrade the antibiotics adsorbed on the surface, preventing the adsorption sites on the biochar surface from being saturated, thereby realizing the synergistic cycle of adsorption-catalysis, improving the overall degradation efficiency, effectively combining the advantages of the two, giving full play to the photocatalytic performance of the composite material, and the obtained composite material has significant improvements in terms of functional groups, pore properties, surface active sites, catalytic degradation ability, etc. Summary of the Invention
[0007] Aiming at the disadvantages of the above-mentioned prior art, the present invention provides a preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material. Specifically, it includes the following steps:
[0008] (1) Crush and screen the biomass raw material, wash and dry it, then mix it with an alkaline solution and stir until the solution becomes thick.
[0009] (2) Add titanium dioxide to the solution in step (1) and carry out hydrothermal treatment.
[0010] (3) After the hydrothermal treatment is completed, pour out the supernatant, carry out centrifugal washing, discard the supernatant, soak the precipitate with hydrochloric acid, then carry out centrifugal washing until it is neutral, dry it, and finally carry out secondary pyrolysis to obtain the catalytic material.
[0011] Preferably, the alkaline solution in step (1) is one or several of potassium hydroxide solution, sodium hydroxide solution, calcium hydroxide solution, and aluminum hydroxide solution mixed in any proportion, and the concentration of the alkaline solution is 0.01 - 20 mol / L.
[0012] More preferably, the alkaline solution in step (1) is potassium hydroxide solution.
[0013] Preferably, in step (1), the solid-liquid ratio of the biomass to the alkali solution is 1:5 to 50:250, with the unit: g:ml.
[0014] Preferably, in step (1), the diameter of the sieve used for sieving is 2 mm, and the drying conditions are drying at 40 - 150 °C for 1 - 60 h.
[0015] Preferably, the mass ratio of the biomass to the titanium dioxide is 0.5:1 to 5:1.
[0016] Preferably, the biomass raw material is agricultural waste.
[0017] More preferably, the biomass is corn straw.
[0018] Preferably, in step (2), the reaction vessel used for hydrothermal treatment is a reaction kettle with a polytetrafluoroethylene lining, and the volume is selected to be 100 - 300 ml.
[0019] Preferably, in step (2), the hydrothermal treatment is carried out in a forced-air drying oven, and the hydrothermal treatment conditions are: treating at 80 °C - 220 °C for 12 - 48 h.
[0020] Preferably, in step (3), the conditions for centrifugation treatment are: centrifuging at a speed of 4000 - 8000 rpm for 10 - 30 min.
[0021] Preferably, in step (3), the concentration of the hydrochloric acid is 0.01 - 10 mol / L, and the drying temperature is 60 - 120 °C.
[0022] Preferably, in step (3), the conditions for secondary pyrolysis are: in an N 2 atmosphere, the reaction heating rate is 2 - 10 °C / min, and the reaction is carried out at 300 - 700 °C for 1 - 4 h.
[0023] The technical effects of the present invention:
[0024] (1) The present invention innovatively provides a brand-new idea and approach for synthesizing a biomass-based one-dimensional nano titanium dioxide advanced oxidation catalytic material. Compared with the prior art, the manufacturing process of the present invention has remarkable simplicity and high efficiency, and can greatly reduce the manufacturing cost of similar materials.
[0025] (2) In an alkaline hydrothermal environment, the present invention can precisely control the growth of titanium dioxide on the biomass along a specific crystal plane by regulating key parameters such as temperature, reaction time, and alkali solution concentration, thereby forming a one-dimensional nanostructure with unique advantages. This one-dimensional nanostructure has a higher specific surface area, can provide more active sites, and at the same time has a shorter electron transport path, which is conducive to the rapid separation and transport of photo-generated carriers, and significantly improves the catalytic activity of the material.
[0026] (3) Further, through the secondary pyrolysis process, the crystal structure of the one-dimensional nano-titanium dioxide can be further improved, significantly enhancing its crystallinity and effectively reducing crystal defects. This not only significantly improves the catalytic performance of the catalytic material but also enhances its structural stability, thereby greatly improving the degradation ability of pollutants.
[0027] (4) The process involved in the present invention has wide applicability and can be applied to a variety of biomass raw materials and titanium dioxide precursors. By flexibly adjusting process parameters, one-dimensional nano-titanium dioxide / biochar composites that meet the diverse requirements of different application fields can be prepared, which have extremely high practical value and application potential. Description of the Drawings
[0028] Figure 1 XRD patterns of the catalysts prepared in Examples 1-5. Detailed Embodiments
[0029] The present invention will be further described in detail below with reference to the drawings and specific embodiments, but the protection scope of the present invention is not limited to the content described.
[0030] Example 1
[0031] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0032] (1) Weigh 1 g of washed and dried corn straw biomass powder and put it into a beaker containing 50 mL of potassium hydroxide alkali solution with a concentration of 1 mol / L, and stir it on a magnetic stirrer to make it a thick solution.
[0033] (2) Weigh 1 g of nano-titanium dioxide and add it to the solution in step (1), transfer the mixture to a 100 ml polytetrafluoroethylene-lined high-pressure reaction kettle, and place the reaction kettle in a forced-air drying oven at 180 °C for hydrothermal reaction for 24 h.
[0034] (3) After the reaction is completed, take out the reaction kettle, pour out the supernatant, centrifuge and wash the precipitate, and discard the supernatant; soak the filtered precipitate in 0.1 mol / L hydrochloric acid for 24 h, then wash it with water until neutral, dry it, and finally, in an N 2 atmosphere, heat it to 500 °C at a rate of 10 °C / min and keep it at this temperature for 2 h to obtain the catalyst.
[0035] Example 2
[0036] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0037] (1) Weigh 3 g of washed and dried corn straw biomass powder and put it into a beaker containing 150 mL of a mixed alkali solution of potassium hydroxide and sodium hydroxide with a concentration of 1 mol / L. Stir it on a magnetic stirrer to make it a thick solution.
[0038] (2) Weigh 1 g of nano-titanium dioxide and add it to the solution in step (1). Transfer the mixture to a 200 ml polytetrafluoroethylene-lined autoclave, and place the autoclave in a forced-air drying oven at 200 °C for hydrothermal reaction for 12 h.
[0039] (3) After the reaction is completed, take out the autoclave, pour out the supernatant, centrifuge and wash, and discard the supernatant; soak the precipitate obtained by filtration in 1 mol / L hydrochloric acid for 12 h, then wash it with water until neutral, dry it, and finally, under a N 2 atmosphere, heat it to 500 °C at a rate of 5 °C / min and keep it at this temperature for 2 h to obtain the catalyst.
[0040] Example 3
[0041] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0042] (1) Weigh 5 g of washed and dried corn straw biomass powder and put it into a beaker containing 250 mL of a sodium hydroxide alkali solution with a concentration of 1 mol / L. Stir it on a magnetic stirrer to make it a thick solution.
[0043] (2) Weigh 1 g of nano-titanium dioxide and add it to the solution in step (1). Transfer the mixture to a 300 ml polytetrafluoroethylene-lined autoclave, and place the autoclave in a forced-air drying oven at 120 °C for hydrothermal reaction for 16 h.
[0044] (3) After the reaction is completed, take out the autoclave, pour out the supernatant, centrifuge and wash, and discard the supernatant; soak the precipitate obtained by filtration in 0.1 mol / L hydrochloric acid for 24 h, then wash it with water until neutral, dry it, and finally, under a N 2 atmosphere, heat it to 700 °C at a rate of 10 °C / min and keep it at this temperature for 2 h to obtain the catalyst.
[0045] Example 4
[0046] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0047] (1) Weigh 1 g of washed and dried corn straw biomass powder and put it into a beaker containing 50 mL of a calcium hydroxide alkali solution with a concentration of 5 mol / L. Stir it on a magnetic stirrer to make it a thick solution.
[0048] (2) Weigh 1 g of nano-titanium dioxide and add it to the solution in step (1). Transfer the mixture to a 100 ml polytetrafluoroethylene-lined high-pressure reaction kettle, and place the reaction kettle in a forced-air drying oven at 220 °C for hydrothermal reaction for 36 h.
[0049] (3) After the reaction is completed, take out the reaction kettle, pour out the supernatant, centrifuge and wash, and discard the supernatant; soak the precipitate obtained by filtration in 0.5 mol / L hydrochloric acid for 36 h, then wash it with clear water until neutral, dry it, and finally, under N 2 atmosphere, heat it to 700 °C at a rate of 5 °C / min and hold for 2 h to obtain the catalyst.
[0050] Example 5
[0051] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0052] (1) Weigh 3 g of washed and dried corn straw biomass powder and put it into a beaker containing 250 mL of aluminum hydroxide alkali solution with a concentration of 10 mol / L, and stir it on a magnetic stirrer to make it a thick solution.
[0053] (2) Weigh 1 g of nano-titanium dioxide and add it to the solution in step (1). Transfer the mixture to a 300 ml polytetrafluoroethylene-lined high-pressure reaction kettle, and place the reaction kettle in a forced-air drying oven at 200 °C for hydrothermal reaction for 24 h.
[0054] (3) After the reaction is completed, take out the reaction kettle, pour out the supernatant, centrifuge and wash, and discard the supernatant; soak the precipitate obtained by filtration in 0.5 mol / L hydrochloric acid for 36 h, then wash it with clear water until neutral, dry it, and finally, under N 2 atmosphere, heat it to 500 °C at a rate of 10 °C / min and hold for 2 h to obtain the catalyst.
[0055] The surface structure properties of the catalysts prepared in Examples 1 to 5 are shown in Table 1.
[0056] Table 1
[0057]
[0058] Comparative Example 1
[0059] A preparation method of a porous biochar material, comprising the following steps:
[0060] (1) Weigh 3 g of washed and dried corn straw biomass powder and add it to 150 mL of potassium hydroxide solution with a concentration of 1 mol / L, completely dissolve it to present a thick state, transfer the mixed solution to a 200 mL polytetrafluoroethylene inner liner, carry out hydrothermal reaction at 200 °C for 12 h, take out the reaction kettle after the reaction is completed, centrifuge and wash, and discard the supernatant.
[0061] (2) Immerse the precipitate obtained in step (1) in 0.1 mol / L dilute hydrochloric acid for 24 h, perform the same centrifugation and washing operations until neutral, dry the obtained product at 105 °C, and finally heat it to 500 °C at a heating rate of 5 °C / min under N 2 atmosphere and keep it at this temperature for 2 h to obtain the catalyst.
[0062] Comparative Example 2
[0063] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0064] (1) Weigh 5 g of washed and dried corn straw biomass powder and put it into a beaker containing 250 mL of potassium hydroxide solution with a concentration of 5 mol / L, place the beaker on a magnetic stirrer and stir for 24 h to make it a thick solution, centrifuge and wash, and discard the supernatant.
[0065] (2) Immerse the obtained product in 1 mol / L dilute hydrochloric acid for 12 h, wash it with deionized water until neutral, and dry it; weigh 3 g of the above-treated biomass and 1 g of titanium dioxide, mix them with deionized water, transfer the mixed solution to a 300 mL polytetrafluoroethylene inner liner high-pressure reaction kettle, and place the reaction kettle in a forced-air drying oven at 200 °C for hydrothermal reaction for 20 h.
[0066] (3) Take out the reaction kettle after the reaction is completed, discard the supernatant, centrifuge and wash, and dry; finally, heat the dried product to 500 °C at a rate of 10 °C / min under N 2 atmosphere and keep it at this temperature for 2 h to obtain the catalyst.
[0067] Comparative Example 3
[0068] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0069] (1) Weigh 5 g of washed and dried corn straw biomass powder and put it into a beaker containing 250 ml of potassium hydroxide solution with a concentration of 1 mol / L, place the beaker on a magnetic stirrer and stir for 24 h to make it a thick solution, centrifuge and filter, and discard the supernatant.
[0070] (2) Immerse the obtained product in 0.1 mol / L dilute hydrochloric acid for 12 h, wash it with deionized water until neutral, and then dry it; weigh 3 g of the above-treated biomass and 1 g of titanium dioxide, and under N 2 atmosphere, heat it to 500 °C at a heating rate of 10 °C / min and hold for 2 h to obtain the catalyst.
[0071] Comparative Example 4
[0072] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0073] (1) Weigh 3 g of cleaned and dried corn straw biomass powder and 1 g of titanium dioxide, add them to deionized water to completely dissolve, transfer to a polytetrafluoroethylene inner liner, carry out hydrothermal reaction at 200 °C for 20 h, centrifuge, filter and dry.
[0074] (2) Put the obtained solid product into a quartz boat, and under N 2 atmosphere, heat it to 500 °C at a heating rate of 10 °C / min and hold for 2 h to obtain the catalyst.
[0075] Comparative Example 5
[0076] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0077] Weigh 3 g of cleaned and dried corn straw biomass powder and 1 g of titanium dioxide, mix them evenly and put them into a quartz boat, and under N 2 atmosphere, heat it to 500 °C at a heating rate of 10 °C / min and hold for 2 h to obtain the catalyst.
[0078] Comparative Example 6
[0079] A preparation method of a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, comprising the following steps:
[0080] Mix 1 g of cleaned and dried corn straw biomass powder, 1 g of titanium dioxide and 50 mL of 1 mol / L potassium hydroxide evenly and put them into a quartz boat, and under N 2 atmosphere, heat it to 500 °C at a heating rate of 10 °C / min and hold for 2 h to obtain the catalyst.
[0081] Effect Example
[0082] The following further illustrates the present invention in combination with examples and comparative examples. (Taking ciprofloxacin as a representative pollutant of antibiotics), a method for activating PMS to catalytically degrade ciprofloxacin under light conditions, comprising the following steps:
[0083] Prepare a ciprofloxacin solution with a concentration of 30 mg / L. Take 50 ml and place it in a 50 ml quartz glass tube. Add 0.01 g of the catalytic material respectively and place it under different light conditions for reaction. Add a magnetic stir bar to each quartz glass tube and stir at 500 r / min. React in the dark for one hour. After reaching the adsorption-desorption equilibrium, add PMS to the system to initiate the reaction, and at the same time turn on the light source switch for photocatalytic reaction. Sample every 30 min. Take 3 ml of each sample. After centrifugation and filtration, take the supernatant and filter it through a 0.22 μm membrane. Measure the absorbance of ciprofloxacin in the filtered solution with a UV-spectrophotometer at a wavelength of 278. According to the formula: D = (A 0 -A) / A 0 × 100% (where A 0 is the absorbance of the initial ciprofloxacin solution; A is the absorbance of the solution after sampling and filtering the membrane after reacting for a certain time), calculate the degradation rate. After 180 min of degradation, the performance study of the composite materials under different conditions for catalytic degradation of ciprofloxacin under light conditions is shown in Table 2 below:
[0084] Table 2
[0085] Materials prepared under different conditions Degradation rate Example 1 92.6％ Example 2 96％ Example 3 93.4％ Example 4 91.6％ Example 5 90.2％ Comparative Example 1 32.6％ Comparative Example 2 57.4％ Comparative Example 3 48.9％ Comparative Example 4 63.1％ Comparative Example 5 44.8％ Comparative Example 6 52.6％
[0086] The above table shows the degradation rates of ciprofloxacin by different preparation materials in Examples 1-5 and Comparative Examples 1-6. Examples 1-5 are composite materials obtained by hydrothermal reaction of biomass and titanium dioxide in an alkaline solution followed by secondary pyrolysis. Different ratios of biomass to titanium dioxide, hydrothermal reaction temperatures, and pyrolysis times will have a certain impact on the degradation efficiency, but the impact is relatively small. Some functional groups in biomass, such as hydroxyl groups and carboxyl groups, can interact with the active sites on the surface of the nanostructure through hydrogen bonds, chemical bonds, etc., making the combination between one-dimensional nano-titanium dioxide and biochar closer, improving the stability of the composite material, and making one-dimensional nano-titanium dioxide less likely to agglomerate or undergo crystal transformation under different environmental conditions.
[0087] During the reaction of the materials in Examples 1 to 5, the mechanism of the catalytic degradation synergy is mainly as follows: 1. Adsorption-catalysis synergy: The adsorption of biochar enriches antibiotics on the surface of the catalyst, making it easier for free radicals to contact and react with antibiotic molecules. At the same time, the free radicals generated by photocatalysis and PMS activation can timely degrade the antibiotics adsorbed on the surface, preventing the adsorption sites on the biochar surface from being saturated, thus realizing the synergistic cycle of adsorption-catalysis; 2. Electron transfer synergy: Biochar serves as an electron transfer medium, promoting the rapid transfer of photo-generated electrons in one-dimensional nano-titanium dioxide, reducing the recombination of electron-hole pairs, and at the same time providing more electrons for the activation of PMS. This electron transfer synergy improves the photocatalytic efficiency and PMS activation efficiency, enhances the degradation ability of antibiotics, and improves the overall degradation efficiency.
[0088] The degradation efficiency of Examples 1 to 5 all reached more than 90%, and the structure was stable. After multiple cycles of ciprofloxacin degradation, the catalytic degradation efficiency basically remained unchanged. Comparative Examples 1 to 6 did not go through the complete steps of Examples 1 to 5, and the catalytic degradation efficiency of the prepared materials for ciprofloxacin was relatively low, with the highest only reaching 63.1%. After repeating several times, the degradation efficiency was lower than 20%, indicating that the structure of the materials was not stable enough. This may be because the interfacial binding force between biomass and one-dimensional nano-titanium dioxide is weak, hindering the separation of photo-generated carriers, and at the same time reducing the active sites required for PMS activation, resulting in a low final catalytic degradation efficiency.
[0089] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.
[0090] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material, characterized in that: The specific steps include: (1) crushing and sieving the biomass raw material, washing and drying it, mixing it with an alkaline solution, and stirring it to make the solution thick; (2) adding titanium dioxide to the solution obtained in step (1) and performing a hydrothermal treatment; (3) After the hydrothermal treatment is completed, the supernatant is poured out, centrifuged and washed, the supernatant is discarded, the precipitate is soaked in hydrochloric acid, centrifuged and washed again until neutral, dried, and finally subjected to secondary pyrolysis to obtain a catalytic material.
2. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: The alkaline solution in step (1) is one or more of potassium hydroxide solution, sodium hydroxide solution, calcium hydroxide solution and aluminum hydroxide solution mixed in any proportion, and the concentration of the alkaline solution is 0.01-20 mol / L.
3. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: In step (1), the solid-liquid ratio of the biomass to the alkaline solution is 1:5 to 50:250, in units of g:ml.
4. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: The mesh diameter of the sieve used for sieving in step (1) is 2 mm, and the drying condition is 40-150° C. for 1-60 h.
5. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: The mass ratio of biomass to titanium dioxide is 0.5:1 to 5:
1.
6. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: The reaction vessel used for the hydrothermal treatment in step (2) is a polytetrafluoroethylene-lined reactor with a volume of 100 to 300 ml.
7. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: The hydrothermal treatment in step (2) is carried out in a forced air drying oven, and the hydrothermal treatment conditions are: 80° C. to 220° C. for 12 to 48 hours.
8. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: The centrifugal treatment conditions in step (3) are: centrifugation at a speed of 4000-8000 rpm for 10-30 min.
9. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, characterized in that: The concentration of the hydrochloric acid in step (3) is 0.01-10 mol / L, and the drying temperature is 60-120°C.
10. The method for preparing the one-dimensional nano-titanium dioxide in-situ composite biochar catalytic material according to claim 1, Features: The conditions for the secondary pyrolysis in step (3) are: in a N2 atmosphere, the reaction temperature rise rate is 2 to 10°C / min, React at 300-700℃ for 1-4h.