Vinegar residue biomass charcoal as well as preparation method and application thereof

Abstract

The invention discloses vinegar residue biomass charcoal as well as a preparation method and application thereof, and belongs to a resource recycling technology. The preparation method of the biomass charcoal comprises the following steps: pyrolyzing vinegar residues under an anaerobic condition, and cooling to room temperature to prepare vinegar residue biomass charcoal; the pyrolysis temperature is 400-600 DEG C, and the pyrolysis time is 2-4 hours. The prepared vinegar residue is alkaline biomass charcoal which is large in specific surface area and high in adsorption capacity, has a porous structure and has an adsorption effect on heavy metal ions in a water body. The method not only can effectively utilize wastes, but also can react to purification of a water body environment, and solves the technical problem of low efficiency of adsorbing heavy metal ions by using vinegar residues in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of resource recycling, and specifically relates to vinegar residue biomass charcoal and a preparation method and application thereof. Background Art

[0002] Vinegar lees are mainly the residues left after fermentation of corn, sorghum and other grains or grain husks, which are the raw materials for making vinegar. They are the main by-products of my country's vinegar industry. Vinegar lees are rich in organic acids (such as acetic acid, lactic acid, tartaric acid, etc., about 2.08%) and cellulose (about 29.69%), and are usually used as animal feed, compost and soilless cultivation substrate. my country has abundant vinegar lees resources and a large annual output, but because of its high acidity, slow decay, deterioration and volatilization, it will produce odor and other disadvantages. It will not only affect the sanitation of the city, but also damage the ecological environment. If it is landfilled, it will greatly increase the disposal cost. Therefore, how to reasonably and efficiently dispose of and utilize the huge amount of vinegar lees resources has become one of the focuses of researchers in recent years.

[0003] At present, the removal of heavy metal ions in water bodies is mainly done by precipitating heavy metal ions through a series of chemical reagents. This method not only causes pollution caused by chemical reagents, but also costs a lot. Although this method is relatively simple to operate and has low cost, the precipitate generated requires subsequent treatment, and it is not effective for some heavy metal ions that are difficult to precipitate.

[0004] The removal of heavy metals in water by biochar is mainly based on adsorption, and its main mechanisms include: surface complexation, precipitation and C=Cπ electron bonding, etc.; the removal of heavy metals in soil is mainly based on passivation, and its main mechanisms include: ion exchange, electrostatic adsorption, coprecipitation and surface complexation, etc. The adsorption and fixation of heavy metals by many biochars is achieved by the joint action of multiple mechanisms, rather than a single mechanism. But no matter which mechanism, its principle is to change the existence form of heavy metals in the soil, reduce the exchangeable state content, so as to reduce its biological effectiveness and migration conversion rate, and weaken or eliminate the stress on organisms. Chinese patent CN114130357A discloses a preparation method and application of salt lake brine modified biochar, which uses biochar and salt lake brine to mix and dry to obtain salt lake brine modified biochar. Although salt lake brine modified biochar can effectively remove heavy metal ions, the adsorption performance of the biochar prepared by this method is not high, and it cannot adsorb too many heavy metal ions, which leads to the problem of low adsorption efficiency. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a vinegar lees biomass charcoal and a preparation method and application thereof, so as to solve the technical problem of low efficiency of adsorbing heavy metal ions using vinegar lees in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The invention provides a method for preparing vinegar lees biomass charcoal, comprising pyrolyzing the vinegar lees under anaerobic conditions and cooling to room temperature to obtain the vinegar lees biomass charcoal; the pyrolysis temperature is 400-600°C, and the pyrolysis time is 2h-4h.

[0007] Preferably, the pyrolysis temperature is 450° C. and the pyrolysis time is 3 h.

[0008] Preferably, the vinegar grains are washed and dried before pyrolysis.

[0009] Preferably, the cooled vinegar grains are further subjected to grinding, sieving and drying processes.

[0010] Preferably, the screening process includes passing through a sieve of 0.135 mm to 0.155 mm.

[0011] Preferably, the screening process includes passing through a 0.147 mm sieve.

[0012] Preferably, oxygen-free conditions include under a nitrogen or argon atmosphere.

[0013] The present invention also provides vinegar lees biomass charcoal prepared by the preparation method, which has a multi-microporous structure, a particle size of the vinegar lees biomass charcoal of 1 mm-5 mm, and a pH value of 6.5-8.

[0014] The present invention also provides the use of the vinegar residue biomass charcoal in adsorbing heavy metal ions in a heavy metal ion solution.

[0015] Preferably, the heavy metal ions include Pb 2+ , Hg 2+ or Cr 6+ .

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing vinegar lees biomass charcoal. The vinegar lees are pyrolyzed under anaerobic conditions, which can ensure that no unnecessary oxidation reaction occurs during the preparation of biomass charcoal due to the presence of oxygen, so that the structure of the vinegar lees biomass charcoal becomes porous, and then the surface of the vinegar lees biomass charcoal is rich in more negatively charged functional groups and aromatic compounds, providing more π electron pairs for the adsorption of heavy metal ions. The metal is complexed with the ionized oxygen-containing functional groups through ion exchange to achieve the adsorption of more metal ions, effectively improving the adsorption capacity of the vinegar lees biomass charcoal. It has been experimentally verified that the adsorption efficiency of the vinegar lees biomass charcoal is as high as 99.5%. The pyrolysis temperature is within the range of 400°C-600°C, which can ensure that the organic matter in the vinegar lees is fully carbonized, while avoiding excessive damage to the carbon structure or the generation of harmful substances due to excessively high temperatures; the pyrolysis time is controlled within 2h-4h, which can not only ensure the full progress of the carbonization process, but also improve production efficiency and reduce energy consumption. In addition, the raw material used in the preparation method of the present invention is vinegar lees, which is easy to obtain and greatly reduces the cost.

[0017] Furthermore, the pyrolysis temperature of 450 °C and the pyrolysis time of 3 h were conducive to the formation of biochar with a microporous structure, which is crucial for the adsorption of heavy metal ions.

[0018] Furthermore, washing and drying the vinegar dregs for pretreatment can remove impurities and improve the purity of the biochar, thereby enhancing its adsorption performance.

[0019] Furthermore, grinding treatment helps to break the biochar into smaller particles, increasing its contact area with heavy metal ions; screening treatment can remove particles that are too large or too small, ensuring that the particle size distribution of the biochar is uniform, which is beneficial to the adsorption effect; drying treatment helps to maintain the stability and adsorption activity of the biochar.

[0020] Furthermore, by screening with a sieve of a specific mesh size, the particle size of the biochar can be further controlled and its adsorption performance can be optimized.

[0021] Furthermore, pyrolysis under a nitrogen atmosphere can ensure the realization of an oxygen-free environment, which is beneficial to the preparation of biochar and the improvement of its adsorption performance.

[0022] The present invention also provides a vinegar dregs biochar prepared by the above-mentioned preparation method, which has a multi-microporous structure, thereby providing more adsorption sites, which is beneficial to the adsorption of heavy metal ions; the particle size range of 1mm-5mm makes the biochar have an appropriate specific surface area and inter-particle gaps, which is beneficial to mass transfer and diffusion during the adsorption process; the pH value range of 6.5-8 makes the biochar have better stability and adaptability when adsorbing heavy metal ions. The present invention uses waste vinegar dregs to prepare alkaline biochar with a porous structure, a large specific surface area, and a strong adsorption capacity. The biochar has an adsorption effect on mercury ions in water bodies, which can not only effectively utilize waste, but also react to the purification of the water environment.

[0023] Furthermore, the concentration of 80 mg / L heavy metal ion solution represents the common pollution level. The adsorption performance of biochar can be evaluated through adsorption experiments. Standing for 24 hours ensures the full progress of the adsorption process. The range of the dosage ratio of biochar to heavy metal ion solution ensures the flexibility and practicality of the experiment.

[0024] Furthermore, heavy metal ion solutions such as Pb (NO3)2, HgSO4 or K2Cr2O7 represent common environmental pollutants, and the broad-spectrum adsorption performance of biochar can be evaluated by adsorbing these ions.

[0025] Furthermore, the pH range of 2-6 covers an acidic environment, which is beneficial for the adsorption of heavy metal ions because the solubility and activity of heavy metal ions are higher under acidic conditions. Experimental verification shows that the adsorption of heavy metal ions by vinegar lees biochar is best when the pH value is 3-6. The adsorption method of heavy metal ions by vinegar lees biochar studied in the present invention has the advantages of resource recycling, low environmental pollution and good adsorption, and is a convenient method for rapid heavy metal ion removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM image of the vinegar lees biochar of the present invention; Figure 2 The pH of the present invention is 2+ Influence diagram of adsorption; Figure 3 The adsorbent dosage of the present invention is Pb 2+ Influence diagram of adsorption; Figure 4 The pH of the present invention is Hg 2+ Influence diagram of adsorption; Figure 5 The adsorbent dosage of the present invention is Hg 2+ Influence diagram of adsorption; Figure 6 This is a graph showing the effect of pH on Cr(VI) adsorption in the present invention; Figure 7 This is a graph showing the effect of the dosage of the adsorbent on the adsorption of Cr(VI) according to the present invention; Figure 8 This is the SEM image of the vinegar residue biochar of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0030] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0031] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0032] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0033] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0034] The invention provides a method for preparing vinegar lees biomass charcoal, comprising washing the test vinegar lees with deionized water to remove impurities, and drying for standby use. The washed and dried vinegar lees are used as raw materials, pyrolyzed under anaerobic conditions, and naturally cooled to room temperature under anaerobic conditions after complete carbonization to obtain the solid residue after oil and gas production, namely, vinegar lees biochar. The obtained vinegar lees biochar is mixed and ground, sieved, and stored in a dryer.

[0035] The vinegar dregs are the residues of Jinsushan rice vinegar from Qingchun Vinegar Factory in Fuping, Shaanxi Province. The residues are solid residues after vinegar brewing, and specifically consist of residues after fermentation of corn, sorghum and other grains. The vinegar dregs have a water content of 65%-70%. The air-dried vinegar dregs (water content 10%) contain 9.6%-20.4% crude protein, 15.1%-28% crude fiber, etc. The following embodiments all use the vinegar dregs.

[0036] The present invention also provides an application of vinegar residue biomass charcoal in a heavy metal ion solution, comprising the following steps: Step 1) Prepare a solution of heavy metal ions with a concentration of 50 mg / L-100 mg / L.

[0037] The heavy metal ion solution is any one of Pb (NO3)2, HgSO4 or K2Cr2O7.

[0038] Step 2) Add the vinegar lees biomass charcoal into the heavy metal ion solution and let it stand at room temperature and pressure for 10-24 hours. The dosage ratio of the vinegar lees biomass charcoal to the heavy metal ion solution is (0.05-2) g: 30 mL.

[0039] Step 3) In the solution pH effect test, the vinegar lees biochar was added to a heavy metal ion solution with a pH value of 2-6, and the adsorption effect was observed and tested after standing for 10-24 hours at room temperature and pressure. The dosage ratio of the vinegar lees biochar to the heavy metal ion solution was 1g:30ml.

[0040] Step 4) In the test of the effect of adsorbent dosage, 30 mL of 80 mg / L heavy metal ion solution was taken, and vinegar lees biomass carbon was added. The dosage gradient of vinegar lees biomass carbon was set to: 0.05-2 g. It was allowed to stand for 10-24 h at normal temperature and pressure, and the adsorption effect was observed and tested.

[0041] The vinegar lees biomass charcoal prepared by the present invention has an adsorption effect on heavy metal ions, and the concentration of heavy metal ions is measured by a flame atomic absorption spectrophotometer. The vinegar lees biomass charcoal is measured for heavy metal ions by SEM and FT-IR, and the binding sites for heavy metal ions are studied based on the changes in the absorption peak intensity of the compound and the changes in the absorption peak position, so that effective adsorption of heavy metal ions can be achieved; at the same time, the adsorption effect of the vinegar lees biochar for heavy metal ions is best when the pH is 3-6.

[0042] Example 1 Preparation of vinegar lees biochar: The vinegar lees to be tested were washed with deionized water to remove impurities and dried for use. The washed and dried vinegar lees were used as raw materials and heated to 450°C under nitrogen conditions for 3 hours. After complete carbonization, they were naturally cooled to room temperature in anoxic conditions to obtain the solid residue after oil and gas production - vinegar lees biochar. The samples were mixed and ground, passed through a 0.147 mm sieve, and stored in a desiccator.

[0043] After SEM, Figure 1 and Figure 8 It can be observed that after the vinegar lees are pyrolyzed into biomass charcoal, the carbon elements are etched under the oxidation reaction, and a multi-microporous structure is developed, which provides more binding sites for the adsorption of heavy metal ions. The particle size of the vinegar lees biomass charcoal prepared in this example is 1 mm, and the pH value is 6.5.

[0044] Example 2 Preparation of vinegar lees biochar: The vinegar lees to be tested are washed with deionized water to remove impurities and then dried for use. The washed and dried vinegar lees are used as raw materials, heated to 400°C under argon conditions, heated for 2 hours to completely carbonize, and then naturally cooled to room temperature in anoxic conditions to obtain the solid residue after oil and gas production - vinegar lees biochar. The sample is mixed and ground, passed through a 0.135 mm sieve, and stored in a dryer. The particle size of the vinegar lees biochar prepared in this example is 3 mm, and the pH value is 7.

[0045] Example 3 Preparation of vinegar lees biochar: The vinegar lees to be tested are washed with deionized water to remove impurities and then dried for use. The washed and dried vinegar lees are used as raw materials, heated to 600°C under nitrogen conditions, heated for 4 hours to completely carbonize, and then naturally cooled to room temperature in anoxic conditions to obtain the solid residue after oil and gas production - vinegar lees biochar. The sample is mixed and ground, passed through a 0.155 mm sieve, and stored in a dryer. The particle size of the vinegar lees biochar prepared in this example is 5 mm, and the pH value is 8.

[0046] Example 4 The effect of vinegar residue biomass charcoal on Pb 2+ , Hg 2+ and Cr 6+Adsorption: The concentration is 30 mg / L Pb 2+ , Hg 2+ and Cr 6+ 30 ml of heavy metal ion solution was taken and 1.025 g of vinegar lees biomass charcoal in Example 1 was added. The mixture was left to stand at room temperature and pressure for 24 h to observe the adsorption effect. The results are shown in Table 1. 2+ , Hg 2+ and Cr 6+ The removal rates were all above 95.7%, indicating that the vinegar residue biochar prepared by the present invention had good adsorption efficiency.

[0047] Table 1 Removal effect of vinegar residue biochar on different heavy metal ions

[0048] Example 5 Effect of pH on Pb 2+ The adsorption performance test was conducted by adding the vinegar residue biochar prepared in Example 1 to Pb with pH values ​​of 2, 2.5, 3, 3.5, 4, 5, and 6 (adjusted with 0.1 mol / L HNO3 and 0.1 mol / L NaOH solution). 2+ In the solution of ions, vinegar residue biomass charcoal and Pb 2+ The dosage ratio of the ion solution is 1g:30mL. After standing at room temperature and pressure for 24 hours, observe and test the results. Figure 2 When pH < 3, the effect of vinegar residue biochar on Pb 2+ The adsorption effect of vinegar residue biochar on Pb 2+ The adsorption effect is good.

[0049] Example 6 Effect of the dosage of adsorbent (vinegar residue biochar of Example 1) on the Pb 2+ Adsorption performance test: Take 30 mL, 80 mg / L Pb 2+ The ion solution was prepared and the dosage of vinegar residue biochar was set to 0.05 g, 0.1 g, 0.2 g, 0.3 g, 0.5 g, 1 g, and 2 g. The solution was left to stand for 24 h at room temperature and pressure. The results of the observation and testing are shown in Figure 3 When the adsorption mass is less than 1g, the vinegar residue biomass charcoal has a strong affinity for Pb 2+ The adsorption effect of vinegar residue biochar on Pb increases with the increase of the amount; when the adsorption mass is greater than 1g, the adsorption of 2+ Good adsorption effect.

[0050] Example 7 pH to Hg 2+Adsorption performance test: The vinegar residue biochar prepared in Example 1 was added to Hg with pH values ​​of 2, 2.5, 3, 3.5, 4, 5, and 6 (adjusted with 0.1 mol / L H2SO4 and 0.1 mol / L NaOH solution). 2+ In the solution of ions, vinegar residue biomass charcoal and Hg 2+ The dosage ratio of the ion solution is 1g:30mL. After standing at room temperature and pressure for 24 hours, observe and test the results. Figure 4 When pH < 3, the biochar from vinegar residues has a significant effect on Hg 2+ The adsorption effect of vinegar residue biochar on Hg 2+ The adsorption effect is good.

[0051] Example 8 Effect of the dosage of adsorbent (vinasse biochar prepared in Example 1) on Hg 2+ Adsorption performance test: Take 30mL, 80 mg / L Hg 2+ The ion solution was prepared and the dosage of vinegar residue biochar was set to 0.05 g, 0.1 g, 0.2 g, 0.3 g, 0.5 g, 1 g, and 2 g. The solution was left to stand for 24 h at room temperature and pressure. The results of the observation and testing are shown in Figure 5 When the adsorption mass is less than 1g, the vinegar residue biochar has a 2+ The adsorption effect of vinegar residue biochar on Hg 2+ Good adsorption effect.

[0052] Example 9 Effect of pH on Cr 6+ The adsorption performance of the test: vinegar residue biochar was added to Cr with pH values ​​of 2, 2.5, 3, 3.5, 4, 5, and 6 (adjusted with 0.1 mol / L HCl and 0.1 mol / L NaOH solution). 6+ In the solution of ions, vinegar residue biomass charcoal and Cr 6+ The dosage ratio of the ion solution is 1g:30mL. After standing at room temperature and pressure for 24 hours, observe and test the results. Figure 6 When pH < 3, the effect of vinegar residue biochar on Cr 6+ The adsorption effect of vinegar residue biochar on Cr 6+ The adsorption effect is good.

[0053] Example 10 Effect of the dosage of adsorbent (vinasse biochar prepared in Example 1) on Cr 6+ Adsorption performance test: Take 30 mL, 80 mg / L Cr 6+The ion solution was prepared and the dosage of vinegar residue biochar was set to 0.05 g, 0.1 g, 0.2 g, 0.3 g, 0.5 g, 1 g, and 2 g. The solution was left to stand for 24 h at room temperature and pressure. The results of the observation and testing are shown in Figure 7 When the adsorption mass is less than 1g, the vinegar residue biochar has a significant effect on Cr 6+ The adsorption effect of vinegar residue biochar on Cr increases with the increase of the amount; when the adsorption mass is greater than 1g, the adsorption of vinegar residue biochar on Cr 6+ Good adsorption effect.

[0054] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing vinegar lees biochar, characterized in that: The method comprises pyrolyzing vinegar lees under anaerobic conditions and cooling to room temperature to obtain vinegar lees biomass charcoal; the pyrolysis temperature is 400-600°C and the pyrolysis time is 2 h-4 h.

2. The method for preparing vinegar lees biochar according to claim 1, characterized in that: The pyrolysis temperature is 450°C and the pyrolysis time is 3h.

3. The method for preparing vinegar lees biochar according to claim 1, characterized in that: The vinegar grains are also washed and dried before pyrolysis.

4. The method for preparing vinegar lees biochar according to claim 1, characterized in that: The cooled vinegar lees also undergoes grinding, screening and drying processes.

5. The method for preparing vinegar lees biochar according to claim 4, characterized in that: The screening process includes passing through a 0.135mm-0.155mm sieve.

6. The method for preparing vinegar lees biochar according to claim 5, characterized in that: The screening process includes passing through a 0.147 mm screen.

7. The method for preparing vinegar lees biochar according to claim 1, characterized in that: Anaerobic conditions include under a nitrogen or argon atmosphere.

8. The vinegar lees biomass charcoal prepared by the method for preparing vinegar lees biomass charcoal according to any one of claims 1 to 7, characterized in that: The vinegar lees biomass charcoal has a microporous structure, the particle size of the vinegar lees biomass charcoal is 1 mm-5 mm, and the pH value is 6.5-8.

9. Use of the vinegar residue biochar according to claim 8 in adsorbing heavy metal ions in a heavy metal ion solution.

10. The use of vinegar residue biochar in adsorbing heavy metal ions in heavy metal ion solution according to claim 9, characterized in that: Heavy metal ions including Pb 2+ , Hg 2+ or Cr 6+ .

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