Wood vinegar modified charcoal, saline-alkali soil modifier containing wood vinegar modified charcoal and preparation methods of wood vinegar modified charcoal and saline-alkali soil modifier

Abstract

The invention relates to the technical field of modified biochar, in particular to wood vinegar modified biochar, a saline-alkali soil modifier containing the wood vinegar modified biochar and a preparation method of the wood vinegar modified biochar. The invention provides a preparation method of wood vinegar modified biochar, which comprises the following steps: cleaning and drying biochar, adding the biochar into wood vinegar, stirring at room temperature for 0.5-1 hour, adding a potassium permanganate solution, continuously stirring for 2.5-4 hours, carrying out solid-liquid separation, and collecting solids to obtain the wood vinegar modified biochar. The invention further provides the wood vinegar modified biochar, a saline-alkali soil modifier containing the wood vinegar modified biochar and a preparation method of the wood vinegar modified biochar. The saline-alkali soil improver has excellent sodium ion adsorption capacity and plant growth promoting capacity, inorganic acid, organic acid or various microbial strains do not need to be used in the preparation process, the preparation method is simple and feasible, and the saline-alkali soil improver can be widely applied to development and utilization of saline-alkali soil.

Description

Technical Field

[0001] The present invention relates to the technical field of modified biochar, and particularly relates to a wood vinegar modified biochar, a saline-alkali soil conditioner containing the same, and a preparation method thereof. Background Art

[0002] Biochar is a carbon-containing solid substance obtained by high-temperature pyrolysis of biomass raw materials under oxygen-limited conditions. It has a high carbon content, a large specific surface area, a rich microporous structure, and a small self-specific gravity. At the same time, the biochar surface also has rich functional groups such as hydroxyl, carboxyl, and carbonyl groups. These characteristics enable biochar to be widely used in aspects such as soil improvement, pollutant fixation, and improvement of the yield and quality of agricultural products. However, due to the limited number of functional groups, pores, and specific surface area on the surface of traditional biochar, its adsorption capacity for organic pollutants or metal ions is also affected. Therefore, enhancing its adsorption capacity by modifying biochar has become a research hotspot in the biochar industry. Currently, traditional biochar is mainly modified by chemical methods such as organic modification, loading metal ion modification, and acid-base modification. Among them, acid-base modification is one of the most commonly used chemical modification methods. However, acid-base modification requires the use of a large amount of highly dangerous chemical reagents such as strong acids and strong bases, which not only easily causes environmental pollution but also increases the difficulty of large-scale production.

[0003] The raw material of wood vinegar mainly comes from agricultural and forestry waste, and is composed of organic substances such as phenols, acids, aldehydes, and esters, as well as trace metal elements. It has a large output and is easily obtained, belonging to renewable energy substances. As a new type of green product, it is inexpensive, can effectively promote the recycling of resources, and has good application development prospects.

[0004] Saline-alkali soil is the general term for two types of soils, saline soil and alkaline soil. The fundamental reason for its formation is that the soil moisture condition is poor, and the salts are irregularly distributed in the vertical or horizontal direction, resulting in a high salt content in the surface soil. Saline-alkali soil has defects such as a high content of soluble salts, poor air permeability, poor water permeability, and easy surface hardening, which seriously affect the sustainable development of agriculture and animal husbandry in arid and semi-arid regions and lead to the deterioration of the ecological environment. Currently, there has been research on improving saline-alkali soil by applying wood vinegar to saline-alkali soil. However, due to the complex composition of wood vinegar, the effects of its use concentration and nutrient content on microorganisms in the soil need to be further evaluated. In addition, there has also been research on modifying traditional biochar by compounding wood vinegar with organic acids instead of traditional inorganic acids. However, this biochar modification method requires the compound use of wood vinegar and organic acids, and multiple microorganisms need to be added simultaneously to produce relatively ideal effects. Summary of the Invention

[0005] In view of this, the present invention provides a wood vinegar modified biochar, a saline-alkali soil conditioner containing the same, and a preparation method thereof. The saline-alkali soil conditioner has excellent sodium ion adsorption capacity and plant growth promotion ability, effectively solving the problem of difficult utilization of saline-alkali soil.

[0006] To solve the above technical problems, the present invention provides a preparation method of wood vinegar modified biochar. The steps include: cleaning and drying the biochar, adding it to the wood vinegar, stirring at room temperature for 0.5 - 1 h, adding potassium permanganate solution and continuing to stir for 2.5 - 4 h, separating the solid and liquid, and collecting the solid to obtain the wood vinegar modified biochar.

[0007] The wood vinegar modified biochar provided by the present invention uses wood vinegar and potassium permanganate to modify the surface of the biochar in sequence. The acidic wood vinegar can not only increase the specific surface area and pore volume of the biochar, but also the organic substances such as phenols, acids, aldehydes, and esters contained in it interact with the hydroxyl groups, carboxyl groups, and carbonyl groups on the surface of the biochar, increasing the number of functional groups on the surface of the biochar. Secondly, while potassium permanganate consolidates the framework structure of the biochar and enables it to maintain a high sodium ion adsorption capacity, the high-valent manganese element will be reduced to manganese dioxide by a large number of oxygen-containing functional groups on the surface of the biochar and attached to the surface of the biochar, thereby further improving the sodium ion adsorption capacity of the biochar, and indirectly promoting the germination and growth of crops.

[0008] Preferably, the biochar is corn straw biochar and / or wheat straw biochar, and the wood vinegar is straw wood vinegar.

[0009] The corn straw biochar or wheat straw biochar is prepared as follows: The crushed corn straw or wheat straw is calcined at a high temperature of 450 - 550 °C in a tube furnace for 5 - 8 h under oxygen-limited conditions, cooled and then crushed and sieved again to obtain the biochar. The acidic by-product obtained from the preparation of the biochar is used as the straw wood vinegar.

[0010] Preferably, the particle size of the wood vinegar modified biochar is not greater than 200 μm.

[0011] Preferably, the addition amount of biochar in each liter of wood vinegar is 30 - 40 g.

[0012] Preferably, the volume ratio of the potassium permanganate solution to the wood vinegar is 1:5 - 8, and further preferably 1:6.

[0013] Preferably, the concentration of the potassium permanganate solution is 0.1 - 0.2 mol / L, and further preferably 0.12 mol / L.

[0014] The above-mentioned preferred volume ratio of potassium permanganate solution to wood vinegar liquid and the concentration of potassium permanganate solution can not only ensure that a certain number of functional groups are retained on the surface of the biochar, but also enable the generated manganese dioxide to adhere to the surface of the biochar as much as possible, thereby greatly improving the adsorption of sodium ions by the biochar.

[0015] The second aspect of the present invention provides a wood vinegar liquid-modified biochar, which is prepared according to the above preparation method.

[0016] The third aspect of the present invention provides a saline-alkali soil conditioner, comprising 40-60 parts of the above-mentioned wood vinegar liquid-modified biochar, 5-12 parts of Bacillus licheniformis, and 1-1.5 parts of dodecyl dimethyl benzyl ammonium bromide.

[0017] Among them, the preservation number of the Bacillus licheniformis is CGMCC No. 32787. This Bacillus licheniformis is an electroactive microorganism, which can improve the adsorption performance of sodium ions through electron transfer, and can survive normally in the harsh saline-alkali soil, has a certain preventive effect on soil compaction, and has a strong plant growth-promoting ability.

[0018] Electroactive microorganisms are a special type of microorganisms that can transfer electrons outside the cell and conduct direct or indirect electron exchange with electron donors or acceptors in the environment. This ability makes electroactive microorganisms play an important role in bioelectrochemical systems, such as converting the chemical energy of organic matter into electrical energy in microbial fuel cells, degrading pollutants in bioremediation technologies, and promoting the metal corrosion process.

[0019] The saline-alkali soil conditioner provided by the present invention, which contains the above-mentioned wood vinegar liquid-modified biochar, Bacillus licheniformis, and dodecyl dimethyl benzyl ammonium bromide, has an obvious improvement effect on saline-alkali soil. This is because Bacillus licheniformis can use the wood vinegar liquid-modified biochar as a nutrient source, thereby promoting plant germination and root growth. At the same time, the addition of a small amount of dodecyl dimethyl benzyl ammonium bromide can accelerate the reproduction rate of Bacillus licheniformis, thereby enhancing the plant growth-promoting effect. Through the synergistic cooperation of the wood vinegar liquid-modified biochar, Bacillus licheniformis, and dodecyl dimethyl benzyl ammonium bromide, the saline-alkali soil conditioner has excellent sodium ion adsorption ability and growth-promoting ability at the same time, effectively improving the problem that saline-alkali soil is difficult to develop and utilize.

[0020] Preferably, the effective viable count in the saline-alkali soil conditioner is 10 8 -10 10 cfu / g.

[0021] The fourth aspect of the present invention provides a preparation method of the above-mentioned saline-alkali soil conditioner, specifically: mixing the wood vinegar liquid-modified biochar, Bacillus licheniformis, and dodecyl dimethyl benzyl ammonium bromide evenly in proportion to obtain the saline-alkali soil conditioner.

[0022] Beneficial effects obtained by the present invention: The soil conditioner for saline-alkali soil provided by the present invention only needs to use the wood vinegar-modified biochar in combination with Bacillus licheniformis and a trace amount of dodecyl dimethyl benzyl ammonium bromide to simultaneously have excellent sodium ion adsorption capacity and plant growth promotion ability. Moreover, during the preparation process, inorganic acids and organic acids are not required, and multiple microbial strains do not need to be added simultaneously. The preparation method is simple and feasible, and it can be widely applied to the development and utilization of saline-alkali soils, especially saline-alkali soils under sodium ion stress. Specific embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following specific embodiments are used to further elaborate on the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] In the following examples and comparative examples, the Bacillus licheniformis used was obtained in the following manner:

[0025] The dilution plate coating method was adopted to isolate microorganisms from saline-alkali soil samples using an LB medium with a salt content of 5%. Strains with larger colony diameters were selected for cultivation in LB liquid medium. The soaking method was used to determine the effects of the strains on the germination and growth of wheat seeds on a 1% salt-containing plate. One strain with good salt tolerance and growth promotion effects was obtained. After molecular biological identification, it was identified as Bacillus licheniformis, and its 16S rDNA is shown in SEQ ID NO.1. This strain forms a biofilm at the anode after 24 hours of inoculation under an electric field of 0.5 mA and is an electroactive microorganism.

[0026] Bacillus licheniformis was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on November 25, 2024, with the deposit number CGMCC No. 32787 and the deposit address being No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0027] The corn straw biochar or wheat straw biochar used was prepared according to the following method: The corn straw or wheat straw was crushed into blocks with a size of 2 - 4 cm, placed in a tube furnace, heated to 500 °C at a heating rate of 10 °C / min under a nitrogen atmosphere for 6 hours of high-temperature calcination, cooled and then crushed through a 200-mesh sieve to obtain biochar. The acidic by-product obtained from the preparation of biochar was used as straw wood vinegar.

[0028] Example 1

[0029] The present invention provides a wood vinegar-modified biochar, which is prepared according to the following method:

[0030] The corn straw biochar was ultrasonically cleaned in water, filtered, dried, cooled, and then dispersed in the straw wood vinegar solution at a ratio of 35 g / L, and stirred at room temperature for 0.8 h. Then, a 0.12 mol / L potassium permanganate solution was added at a ratio of 1:6 (potassium permanganate solution: wood vinegar solution), and stirring was continued for 3 h. After that, solid-liquid separation was carried out and the solid was collected, dried, cooled, and sieved to obtain the wood vinegar solution-modified biochar with an average particle size of 152 μm.

[0031] Example 2

[0032] An embodiment of the present invention provides a wood vinegar solution-modified biochar, which is prepared by the following method:

[0033] The wheat straw biochar was ultrasonically cleaned in water, filtered, dried, cooled, and then dispersed in the straw wood vinegar solution at a ratio of 30 g / L, and stirred at room temperature for 0.5 h. Then, a 0.1 mol / L potassium permanganate solution was added at a ratio of 1:5 (potassium permanganate solution: wood vinegar solution), and stirring was continued for 2.5 h. After that, solid-liquid separation was carried out and the solid was collected, dried, cooled, and sieved to obtain the wood vinegar solution-modified biochar with an average particle size of 141 μm.

[0034] Example 3

[0035] An embodiment of the present invention provides a wood vinegar solution-modified biochar, which is prepared by the following method:

[0036] The corn straw biochar was ultrasonically cleaned in water, filtered, dried, cooled, and then dispersed in the straw wood vinegar solution at a ratio of 40 g / L, and stirred at room temperature for 1 h. Then, a 0.2 mol / L potassium permanganate solution was added at a ratio of 1:8 (potassium permanganate solution: wood vinegar solution), and stirring was continued for 3.5 h. After that, solid-liquid separation was carried out and the solid was collected, dried, cooled, and sieved to obtain the wood vinegar solution-modified biochar with an average particle size of 160 μm.

[0037] Example 4

[0038] An embodiment of the present invention provides a saline-alkali soil conditioner, which is prepared by the following method:

[0039] 50 parts of the wood vinegar solution-modified biochar prepared in Example 1, 10 parts of Bacillus licheniformis, and 1.2 parts of dodecyl dimethyl benzyl ammonium bromide were mixed evenly to obtain the saline-alkali soil conditioner.

[0040] Example 5

[0041] An embodiment of the present invention provides a saline-alkali soil conditioner, which is prepared by the following method:

[0042] Mix 40 parts of the wood vinegar modified biochar prepared in Example 2, 5 parts of Bacillus licheniformis, and 1 part of dodecyl dimethyl benzyl ammonium bromide evenly to obtain a saline-alkali soil conditioner.

[0043] Example 6

[0044] An embodiment of the present invention provides a saline-alkali soil conditioner, which is prepared according to the following method:

[0045] Mix 60 parts of the wood vinegar modified biochar prepared in Example 3, 12 parts of Bacillus licheniformis, and 1.5 parts of dodecyl dimethyl benzyl ammonium bromide evenly to obtain a saline-alkali soil conditioner.

[0046] Comparative Example 1

[0047] This comparative example provides a wood vinegar modified biochar, the preparation method of which is similar to that in Example 1, the difference is that only wood vinegar is used instead of potassium permanganate solution to modify the biochar, and the remaining steps and materials are the same as those in Example 1. The average particle size of the obtained wood vinegar modified biochar is 116 μm.

[0048] Comparative Example 2

[0049] This comparative example provides a wood vinegar modified biochar, the preparation method of which is similar to that in Example 1, the difference is that the concentration of the potassium permanganate solution used is 0.06 mol / L, and the remaining steps and materials are the same as those in Example 1. The average particle size of the obtained wood vinegar modified biochar is 132 μm.

[0050] Comparative Example 3

[0051] This comparative example provides a wood vinegar modified biochar, the preparation method of which is similar to that in Example 1, the difference is that the concentration of the potassium permanganate solution used is 0.3 mol / L, and the remaining steps and materials are the same as those in Example 1. The average particle size of the obtained wood vinegar modified biochar is 170 μm.

[0052] Comparative Example 4

[0053] This comparative example provides a wood vinegar modified biochar, the preparation method of which is similar to that in Example 1, the difference is that only potassium permanganate solution is used instead of wood vinegar to modify the biochar, and the remaining steps and materials are the same as those in Example 1. The average particle size of the obtained wood vinegar modified biochar is 100 μm.

[0054] Comparative Example 5

[0055] This comparative example provides a saline-alkali soil conditioner, the preparation method of which is similar to that in Example 4, the difference is that dodecyl dimethyl benzyl ammonium bromide is not added.

[0056] Comparative Example 6

[0057] This comparative example provides a saline-alkali soil conditioner, and its preparation method is similar to that of Example 4, except that dodecyl dimethyl benzyl ammonium bromide is replaced by cetyl trimethyl ammonium bromide.

[0058] Comparative Example 7

[0059] This comparative example provides a saline-alkali soil conditioner, and its preparation method is similar to that of Example 4, except that the biochar used is not modified with wood vinegar and potassium permanganate.

[0060] Comparative Example 8

[0061] This comparative example provides a saline-alkali soil conditioner, and its preparation method is similar to that of Example 4, except that the biochar used is the wood vinegar-modified biochar prepared in Comparative Example 1.

[0062] Comparative Example 9

[0063] This comparative example provides a saline-alkali soil conditioner, and its preparation method is similar to that of Example 4, except that the biochar used is the wood vinegar-modified biochar prepared in Comparative Example 4.

[0064] Comparative Example 10

[0065] This comparative example provides a saline-alkali soil conditioner, and its preparation method is similar to that of Example 4, except that the electroactive microorganism Bacillus licheniformis is not added.

[0066] Test Example 1

[0067] The specific surface area, pore volume and pH of the wood vinegar-modified biochars obtained in Examples 1 to 3 and Comparative Example 1 and the corresponding original biochars were measured by the nitrogen adsorption method respectively, and the results are shown in Table 1.

[0068] Table 1

[0069]

[0071] As can be seen from Table 1, compared with the unmodified corn straw biochar or wheat straw biochar, the specific surface area and pore volume of the modified biochars obtained in Examples 1 to 3 are significantly increased, indicating that the preparation method of the wood vinegar-modified biochar provided by the present invention can successfully increase the specific surface area and pore volume of the biochar, and the modified biochar changes from alkaline to acidic, which is more suitable for the improvement of saline-alkali land. By comparing Example 1 and Comparative Example 1, it can be seen that further modification of the biochar with potassium permanganate solution can further increase the specific surface area of the biochar, but has no obvious effect on the pore volume.

[0072] Test Example 2

[0073] Prepare a 5 g / L Na2CO3 solution to simulate the leachate of saline-alkali soil under sodium ion stress, and test the improvement effects of the corresponding unmodified biochar, the saline-alkali soil improvers obtained in Examples 4 to 6 and Comparative Examples 5 to 9, specifically as follows: Take 200 mL of a 5 g / L Na2CO3 solution in a 500 mL conical flask, add 2 g of the saline-alkali soil improver respectively, seal the bottle mouth with a sealing film, place it in a constant temperature oscillator and shake for 24 h at a speed of 120 rpm. Take the supernatant, measure its sodium ion concentration with an atomic absorption spectrometer, and calculate the adsorption performance of the saline-alkali soil improver for sodium ions (calculated as Na2CO3) according to the following formula.

[0074]

[0075] , where C0 and C e respectively represent the initial concentration and the concentration at adsorption equilibrium of the Na2CO3 solution, V represents the solution volume, and m is the mass of the added saline-alkali soil improver. The calculation results are shown in Table 2.

[0076] Table 2

[0077]

[0078] It can be seen from the test results in Table 2 that the saline-alkali soil improver provided by the present invention has a much higher adsorption capacity for sodium ions than the unmodified biochar. Moreover, it can be seen from Comparative Example 5 that the addition of a small amount of dodecyl dimethyl benzyl ammonium bromide has no obvious effect on the sodium ion adsorption capacity of the modified biochar; it can be seen from Comparative Examples 8 and 9 that when only using wood vinegar or potassium permanganate solution to modify the biochar, the sodium ion adsorption capacity of the obtained modified biochar is significantly reduced, while when the two are used to modify the biochar successively, the sodium ion adsorption capacity of the obtained saline-alkali soil improver is significantly improved.

[0079] Test Example 3

[0080] Respectively add the modified biochar obtained in Examples 1 to 3, the saline-alkali soil improvers obtained in Comparative Examples 5 to 10 and Examples 4 to 6 to the saline-alkali land to be repaired at a dosage of 100 kg / mu. After rotary tillage, plant wheat 30 days later. At the same time, use the saline-alkali land without using any biochar or improver as a blank control. After 1 month of germination and growth, count the emergence rate and plant height of wheat. The results are shown in Table 3. Among them, the saline-alkali land used for testing is medium sodium soil.

[0081] Table 3

[0082]

[0083] As can be seen from the data in Table 3, after applying the saline-alkali soil conditioner provided by the present invention to the saline-alkali soil under sodium ion stress, the germination rate of wheat is as high as over 99.5%, and the plant height of wheat also increases significantly. When the trace dodecyl dimethyl benzyl ammonium bromide is not added to the saline-alkali soil conditioner (Comparative Example 5), the germination rate and plant height of the corresponding wheat both increase, indicating that the trace dodecyl dimethyl benzyl ammonium bromide can enhance the growth promotion effect on wheat; when the dodecyl dimethyl benzyl ammonium bromide is replaced with cetyl trimethyl ammonium bromide (Comparative Example 6), although the germination rate and plant height of the corresponding wheat are improved compared with Comparative Example 5, the improvement effect is not obvious, indicating that the dodecyl dimethyl benzyl ammonium bromide can significantly enhance the growth promotion effect on wheat; when the saline-alkali soil conditioner is prepared using unmodified biochar (Comparative Example 7), the germination rate and plant height of the corresponding wheat both decrease, which is because the sodium ion concentration in the saline-alkali soil is relatively high due to the use of unmodified biochar with wood vinegar, affecting the germination and growth of wheat; as can be seen from Comparative Example 8 and Comparative Example 9, when only wood vinegar or potassium permanganate solution is used to modify the biochar, although the germination rate and plant height of wheat are significantly higher than those of the blank control group, since less sodium ions in the soil are adsorbed by the biochar, the germination rate and plant height of wheat are still lower than those in Examples 4 to 6; as can be seen from Comparative Example 10, when the saline-alkali soil conditioner does not contain Bacillus licheniformis, the germination rate and plant height of wheat both decrease significantly, indicating that Bacillus licheniformis has a promoting effect on the germination and growth of crops.

[0084] The above is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A preparation method of wood vinegar modified biochar, characterized in that the steps Comprising: Wash and dry the biochar, add it to the wood vinegar solution, stir at room temperature for 0.5 - 1 h, add potassium permanganate solution and continue stirring for 2.5 - 4 h, separate the solid and liquid, and collect the solid to obtain wood vinegar-modified biochar.

2. The preparation method of the wood vinegar modified biochar according to claim 1, characterized in that, The biochar is corn straw biochar and / or wheat straw biochar, and the wood vinegar solution is straw wood vinegar solution.

3. The preparation method of the wood vinegar modified biochar according to claim 1, characterized in that, The particle size of the wood vinegar-modified biochar is not greater than 200 μm.

4. The preparation method of the wood vinegar modified biochar according to claim 1, characterized in that, The addition amount of biochar in each liter of wood vinegar solution is 30 - 40 g.

5. The preparation method of the wood vinegar modified biochar according to claim 1, characterized in that The volume ratio of the potassium permanganate solution to the wood vinegar solution is 1:5 - 8.

6. The preparation method of the wood vinegar modified biochar according to claim 1 or 5, characterized in that The concentration of the potassium permanganate solution is 0.1 - 0.2 mol / L.

7. A wood vinegar modified biochar, characterized in that, Prepared according to the preparation method described in any one of claims 1 - 6.

8. A saline-alkali soil conditioner, characterized in that, Comprising 40 - 60 parts of the wood vinegar-modified biochar described in claim 7, 5 - 12 parts of Bacillus licheniformis, and 1 - 1.5 parts of dodecyl dimethyl benzyl ammonium bromide.

9. The saline-alkali soil conditioner according to claim 8, wherein, The effective viable count of the saline-alkali soil conditioner is 10 8 -10 10 cfu / g.

10. A method for preparing the saline-alkali soil conditioner according to claim 8 or 9, characterized in that, Mix the wood vinegar-modified biochar, Bacillus licheniformis, and dodecyl dimethyl benzyl ammonium bromide evenly in proportion to obtain the saline-alkali soil conditioner.

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