Hot alkali modified waste vinegar residue-based biomass carbon material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of electrochemical sensors, and particularly relates to a hot alkali modified waste vinegar residue-based biomass carbon material as well as a preparation method and application thereof. The preparation method comprises the following steps: pretreating industrial waste vinegar residues to obtain clean vinegar residue powder; carbonizing the vinegar residue powder in an inert atmosphere to obtain carbonized vinegar residues; the carbonized vinegar residues are mixed in hot alkali to be activated, and the hot alkali modified waste vinegar residue based biomass carbon material is obtained through aging and other treatment. According to the preparation method disclosed by the invention, porous activation is performed on the surface of the carbonized vinegar residue through hot alkali, so that not only are abundant raised wrinkles and pores formed to increase the surface area, but also abundant nitrogen components and active carbon oxygen functional groups are reserved, and the catalytic reaction activity is effectively improved. The hot alkali modified waste vinegar residue-based biomass carbon material can be used as a sensing material to prepare a high-performance electrochemical biosensor, and the electrochemical sensor constructed by the material can be used for detecting biomolecules such as hydrogen peroxide to obtain a wide detection range.

Description

Technical Field

[0001] The present application relates to the technical field of electrochemical sensors, and in particular to a thermal alkali-modified waste vinegar residue-based biomass carbon material and a preparation method and application thereof. Background Art

[0002] Electrochemical sensors are highly specific and sensitive analytical detection devices with a wide range of applications in many fields such as environment, food, medicine, biology, and clinical analysis. At present, the research on electrochemical sensors mainly focuses on the development of new electrochemically active materials to modify electrodes in order to improve the sensitivity, linear range and other electrochemical sensing properties of target molecule detection. It has great advantages in electrochemical sensing. Biomass carbon is obtained by high-temperature pyrolysis of natural biomass, showing excellent electron transfer kinetics, good conductivity and appropriate biocompatibility. Its physical and chemical properties such as specific surface area, porosity, surface functional groups, and charge properties can be flexibly controlled. It has the characteristics of wide sources, high abundance, low cost, and sustainability. It has gradually become a star material to replace traditional synthetic carbon nanomaterials. Therefore, finding a precursor of biomass carbon with excellent performance and synthesizing functional electrochemical analysis materials is crucial to building a more green and environmentally friendly electrochemical analysis platform.

[0003] The main component of vinegar residue is lignin left over from fermentation of bran and rice husk. It is a kind of acidic corrosive solid waste with high water content produced by the vinegar industry, with an annual output of about 3 million tons. Directly discarding vinegar residue will cause environmental pollution and waste abundant lignin resources. At present, most of the research focuses on using it as a raw material for anaerobic fermentation, but not as a precursor of biomass carbon. Therefore, it is worth exploring and studying the use of vinegar residue to prepare functional electrochemical biomass carbon materials. Summary of the invention

[0004] The present application provides a thermal alkali modified waste vinegar residue-based biomass carbon material and a preparation method and application thereof, in order to solve the technical problem of how to use vinegar residue to prepare functional electrochemical biomass carbon materials in the prior art.

[0005] In a first aspect, the present application provides a method for preparing a waste vinegar residue-based biomass carbon material modified by thermal alkali, comprising the following steps: S1, washing, drying, crushing and sieving the solid waste vinegar residue to obtain clean vinegar residue powder; S2. Carbonizing the vinegar residue powder under an inert atmosphere to obtain carbonized vinegar residue; S3, mixing the carbonized vinegar residue in a certain amount of hot alkaline solution for activation, and obtaining hot alkali modified waste vinegar residue-based biomass carbon material through aging, centrifugation, washing, drying and grinding.

[0006] Optionally, the hot alkaline solution in step S3 is a potassium hydroxide solution or a potassium carbonate solution, and the mass fraction of the hot alkaline solution is 10%-30%; the mass ratio of the alkali used to the carbonized vinegar residue is 10:1.

[0007] Optionally, the temperature of the hot alkaline solution in step S3 is 60°C to 100°C.

[0008] Optionally, the activation time in step S3 is 1 to 3 h, and the aging time is 24 h.

[0009] Optionally, the centrifugation speed in step S3 is 8000 rpm - 11000 rpm, and the time is 10 min.

[0010] Optionally, the carbonization heating rate is 2°C / min~5°C / min; the carbonization temperature is 600°C~900°C; and the carbonization time is 1~3 h.

[0011] Optionally, the drying temperature in step S1 is 60-110° C.; the washing solvent is deionized water and anhydrous ethanol; and the sieving mesh size is 80-200 meshes.

[0012] Optionally, the inert atmosphere is either argon or nitrogen.

[0013] In the second aspect, the present application provides a thermal alkali modified waste vinegar residue-based biomass carbon material, which uses solid waste vinegar residue as a precursor and obtains a porous biomass carbon material through high-temperature calcination and thermal alkali activation.

[0014] In a third aspect, the present application provides an application of a thermal alkali-modified waste vinegar residue-based biomass carbon material. The thermal alkali-modified waste vinegar residue-based biomass carbon material prepared by the present invention is applied to the preparation of working electrodes of electrochemical biosensors.

[0015] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art: (1) The present invention uses solid waste vinegar residue as a precursor, and obtains porous biomass carbon material through high-temperature calcination and hot alkali activation. The preparation method has a wide range of raw material sources, low cost, simple process, strong repeatability, and can be mass-produced.

[0016] (2) The present invention converts acidic solid waste vinegar residue into functional carbon-based materials, avoiding secondary pollution of soil by acidic leachate caused by direct landfill, is environmentally friendly, and realizes carbon cycle.

[0017] (3) The present invention uses the prepared waste vinegar residue-based biomass carbon material as a working electrode modification material for an electrochemical sensor for the first time, and has good conductivity, self-nitrogen doping and electron transfer efficiency, thereby inducing hydrogen peroxide and other biological molecules to transfer electrons on the surface of the material, thereby realizing a rapid catalytic reaction of hydrogen peroxide and other biological molecules. Waste vinegar residue-based biomass carbon material can be used as an electrochemical sensing material to build a high-performance biomolecule detection platform, and the electrochemical sensor constructed with waste vinegar residue-based biomass carbon material can realize a wide range of highly sensitive and specific analysis of hydrogen peroxide and other biological molecules, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Characterization diagrams of different materials in Test Example 1 of the present invention; wherein, a is the SEM image of the vinegar residue-based biomass carbon material synthesized in the control example without hot alkali activation; b is the SEM image of the vinegar residue-based biomass carbon material synthesized in Example 4 after hot alkali activation.

[0019] Figure 2 This is the distribution diagram of each element in the hot alkali activated vinegar residue-based biomass carbon material in Test Example 1 of the present invention; wherein, a is the SEM image of the hot alkali activated vinegar residue-based biomass carbon material; b is the element distribution diagram of C; c is the element distribution diagram of N, and d is the element distribution diagram of O.

[0020] Figure 3 This is the electrochemical response test of the hot alkali activated vinegar residue-based biomass carbon material to hydrogen peroxide in Test Example 2 of the present invention; wherein, curves ae in Figure a are the CV responses of the vinegar residue-based biomass carbon material prepared in Example 4 to 0-4 mM hydrogen peroxide; and Figure b is a linear fitting diagram of the response current and hydrogen peroxide concentration of Example 1 (curve a), Example 2 (curve b), Example 3 (curve c), and Example 4 (curve d) to different concentrations of hydrogen peroxide.

[0021] Figure 4 This is a test of the linear response range of the hot alkali activated vinegar residue-based biomass carbon material to hydrogen peroxide in Test Example 2 of the present invention; a is the CV response of the vinegar residue-based biomass carbon material prepared in Example 4 to different concentrations of 10-4000 μM hydrogen peroxide; b is a linear fitting graph of the CV response current size of the vinegar residue-based biomass carbon material prepared in Example 4 to hydrogen peroxide and the hydrogen peroxide concentration.

[0022] Figure 5 This is a test of the selectivity of the hot alkali activated vinegar residue-based biomass carbon material to hydrogen peroxide in Test Example 2 of the present invention. DETAILED DESCRIPTION

[0023] In one embodiment of the present application, a method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material comprises the following steps: S1, washing, drying, crushing and sieving the solid waste vinegar residue to obtain clean vinegar residue powder; S2. Carbonizing the vinegar residue powder under an inert atmosphere to obtain carbonized vinegar residue; S3, mixing the carbonized vinegar residue in a certain amount of hot alkaline solution for activation, and obtaining hot alkali modified waste vinegar residue-based biomass carbon material through aging, centrifugation, washing, drying and grinding.

[0024] In this application, in order to avoid environmental pollution caused by vinegar residue and waste of abundant lignin resources, the present invention uses solid waste vinegar residue as a precursor, and adopts the method of high temperature pyrolysis / hot alkali activation to realize the preparation of vinegar residue-based biomass carbon materials. The rich raised wrinkles and pores and self-doped nitrogen elements provide more reactive sites and higher catalytic activity for the detection of target molecules, which is of great significance for the early diagnosis of diseases. In addition, the present invention first carbonizes the vinegar residue at high temperature, and then activates it in a hot alkali solution below 100°C. The conditions are mild, and no obvious loss is caused to glass containers and heat source instruments. The operation is easy and friendly; at the same time, the side reactions are reduced, making the activation reaction more direct and effective.

[0025] As an optional embodiment, the raw material mass ratio of the hot alkali modified waste vinegar residue-based biomass carbon material is further limited. The hot alkali solution in step S3 is potassium hydroxide or potassium carbonate solution, and the mass fraction of the hot alkali solution is 10%-30%; the mass ratio of the alkali used to the carbonized vinegar residue is 10:1.

[0026] As an optional implementation, the hot alkali activation temperature is further limited, and the temperature of the hot alkali solution in step S3 is 60°C~100°C.

[0027] As an optional implementation, the hot alkali activation time is further limited, and the activation time in step S3 is 1 to 3 hours, and the aging time is 24 hours.

[0028] As an optional embodiment, the centrifugal conditions for the hot alkali modified waste vinegar residue-based biomass carbon material are limited, and the centrifugal speed in step S3 is 8000 rpm - 11000 rpm, and the time is 10 min.

[0029] As an optional implementation, the carbonization heating rate is 2°C / min-5°C / min; the carbonization temperature is 600°C-900°C; and the carbonization time is 1-3h.

[0030] As an optional implementation, the pretreatment process conditions of the vinegar residue are limited, the drying temperature in step S1 is 60-110° C.; the washing solvent is deionized water and anhydrous ethanol; and the sieving mesh size is 80-200 mesh.

[0031] As an optional implementation, the inert atmosphere is further limited to be any one of argon or nitrogen.

[0032] In one embodiment of the present application, the present application provides a thermal alkali modified waste vinegar residue-based biomass carbon material, which uses solid waste vinegar residue as a precursor and obtains a porous biomass carbon material through high-temperature calcination and thermal alkali activation.

[0033] In one embodiment of the present application, the present application provides an application of a thermal alkali-modified waste vinegar residue-based biomass carbon material. The thermal alkali-modified waste vinegar residue-based biomass carbon material prepared by the present invention is applied to the preparation of a working electrode of an electrochemical biosensor.

[0034] Example 1 A method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material comprises the following steps: S1. The vinegar residue purchased from a vinegar factory in Jiangsu was washed three times with deionized water and anhydrous ethanol in sequence, and placed in a blast drying oven at 60°C for 24 h, mechanically crushed, and passed through a 100-mesh sieve to obtain clean vinegar residue powder; S2. In an argon atmosphere, the vinegar residue powder is kept at 600° C. for 2 h at a heating rate of 2° C. / min in a tube furnace, and ground to obtain carbonized vinegar residue; S3. Disperse 500 mg of the carbonized vinegar residue in 50 ml of 10% potassium hydroxide solution, place it on a constant temperature magnetic stirrer and stir it at a uniform speed, keep it at 80°C for 1 hour, stop heating, naturally cool it to room temperature and age it for 24 hours; then centrifuge it at 10,000 rpm for 10 minutes, remove the supernatant, soak the obtained precipitate in 1 M HCl for 3 hours to remove excess potassium hydroxide and impurities, centrifuge it with deionized water and ethanol in turn, and wash it to neutrality; place the precipitate in an 80°C forced air drying oven for 24 hours, grind it, and obtain a vinegar residue-based biomass carbon material.

[0035] Example 2 A method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material comprises the following steps: S1. The vinegar residue purchased from a vinegar factory in Sichuan was washed three times with deionized water and anhydrous ethanol in sequence, placed in a 60°C forced air drying oven for 24 h, mechanically crushed, and passed through a 100-mesh sieve to obtain clean vinegar residue powder; S2, in an argon atmosphere, maintaining the vinegar residue powder at 700°C for 2 h at a heating rate of 2°C / min in a tube furnace, and grinding to obtain carbonized vinegar residue; S3. Disperse 500 mg of the carbonized vinegar residue in 50 ml of 10% potassium hydroxide solution, place it on a constant temperature magnetic stirrer and stir it at a uniform speed, keep it at 80°C for 1 hour, stop heating, naturally cool it to room temperature and age it for 24 hours; then centrifuge it at 10,000 rpm for 10 minutes, remove the supernatant, soak the obtained precipitate in 1 M HCl for 3 hours to remove excess potassium hydroxide and impurities, centrifuge it with deionized water and ethanol in turn, and wash it to neutrality; place the precipitate in an 80°C forced air drying oven for 24 hours, grind it, and obtain a vinegar residue-based biomass carbon material.

[0036] Example 3 A method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material comprises the following steps: S1. The vinegar residue purchased from a vinegar factory in Sichuan was washed three times with deionized water and anhydrous ethanol in sequence, placed in a 60°C forced air drying oven for 24 h, mechanically crushed, and passed through a 100-mesh sieve to obtain clean vinegar residue powder; S2, in an argon atmosphere, maintaining the vinegar residue powder at 800°C for 2 h at a heating rate of 2°C / min in a tube furnace, and grinding to obtain carbonized vinegar residue; S3. Disperse 500 mg of the carbonized vinegar residue in 50 ml of 10% potassium hydroxide solution, place it on a constant temperature magnetic stirrer and stir it at a uniform speed, keep it at 80°C for 1 hour, stop heating, naturally cool it to room temperature and age it for 24 hours; then centrifuge it at 10,000 rpm for 10 minutes, remove the supernatant, soak the obtained precipitate in 1 M HCl for 3 hours to remove excess potassium hydroxide and impurities, centrifuge it with deionized water and ethanol in turn, and wash it to neutrality; place the precipitate in an 80°C forced air drying oven for 24 hours, grind it, and obtain a vinegar residue-based biomass carbon material.

[0037] Example 4 A method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material comprises the following steps: S1. The vinegar residue purchased from a vinegar factory in Sichuan was washed three times with deionized water and anhydrous ethanol in sequence, placed in a 60°C forced air drying oven for 24 h, mechanically crushed, and passed through a 100-mesh sieve to obtain clean vinegar residue powder; S2. In an argon atmosphere, the vinegar residue powder is kept at 900° C. for 2 h at a heating rate of 2° C. / min in a tube furnace, and ground to obtain carbonized vinegar residue; S3. Disperse 500 mg of the carbonized vinegar residue in 50 ml of 10% potassium hydroxide solution, place it on a constant temperature magnetic stirrer and stir it at a uniform speed, keep it at 80°C for 1 hour, stop heating, naturally cool it to room temperature and age it for 24 hours; then centrifuge it at 10,000 rpm for 10 minutes, remove the supernatant, soak the obtained precipitate in 1 M HCl for 3 hours to remove excess potassium hydroxide and impurities, centrifuge it with deionized water and ethanol in turn, and wash it to neutrality; place the precipitate in an 80°C forced air drying oven for 24 hours, grind it, and obtain a vinegar residue-based biomass carbon material.

[0038] Comparative Example 1 A method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material comprises the following steps: S1. The vinegar residue purchased from a vinegar factory in Sichuan was washed three times with deionized water and anhydrous ethanol in sequence, placed in a 60°C forced air drying oven for 24 h, mechanically crushed, and passed through a 100-mesh sieve to obtain clean vinegar residue powder; S2, in an argon atmosphere, maintaining the vinegar residue powder at 800°C for 2 h at a heating rate of 2°C / min in a tube furnace, and grinding to obtain carbonized vinegar residue; S3. Disperse 500 mg of the carbonized vinegar residue in 50 ml of deionized water, place it on a constant temperature magnetic stirrer and stir it at a uniform speed, keep it at 80°C for 1 hour, stop heating, naturally cool it to room temperature and age it for 24 hours; then centrifuge it at 10,000 rpm for 10 min, remove the supernatant, soak the obtained precipitate in 1 M HCl for 3 hours to remove impurities, centrifuge it with deionized water and ethanol in turn, and wash it to neutrality; place the precipitate in an 80°C forced air drying oven for 24 hours, grind it, and obtain a vinegar residue-based biomass carbon material.

[0039] Test Example 1 Based on Example 4 and Comparative Example 1, the morphology of the vinegar residue-based biomass carbon material that has not been activated by hot alkali and the vinegar residue-based biomass carbon material that has been activated by hot alkali were characterized and analyzed by SEM, and the results are shown in the figure. Figure 1 a It can be seen that the surface of the unactivated vinegar residue-based carbon material is flat, while the vinegar residue-based biomass carbon material after hot alkali activation ( Figure 1 b) The surface showed abundant raised wrinkles and pore structures, indicating that hot alkali activation effectively increased the specific surface area of ​​vinegar residue-based biomass carbon materials. Figure 2 It can be seen that C, N, and O elements are evenly distributed on the surface of the material. Nitrogen doping is achieved while synthesizing vinegar residue-based biomass carbon materials, so that there are more active reaction sites on the carbon skeleton, which promotes the oxidative electron transfer rate of target detection and analysis and its rapid response.

[0040] Test Example 2 Based on Examples 1-4, the electrochemical performance of the hydrogen peroxide sensor constructed by hot alkali activated vinegar residue-based biomass carbon material was analyzed. The hot alkali activated vinegar residue-based biomass carbon material was modified on the glassy carbon electrode (GCE) through a standard three-electrode system (7.5 μL 5 mg / mL) to test hydrogen peroxide molecules. The redox reaction occurring at the electrode interface was tested and analyzed by cyclic voltammetry (CV) and chronoamperometry (IT). The results are shown in Figure 2. Figure 3-5 shown.

[0041] from Figure 3 It can be seen that Figure 3 a shows that the vinegar residue-based biomass carbon material synthesized in Example 4 was tested for hydrogen peroxide concentrations of 0-4 mM (curve ae). The results showed that the catalytic current at a potential of about -0.23 V increased with the increase in the concentration of hydrogen peroxide, showing a positive correlation trend, indicating that the prepared vinegar residue-based biomass carbon can respond to changes in the concentration of hydrogen peroxide and can be used to quantitatively analyze the concentration of hydrogen peroxide. Figure 3 Curves ad in b are respectively the linear fitting diagrams of the response current and hydrogen peroxide concentration of Example 1, Example 2, Example 3, and Example 4 to different concentrations of hydrogen peroxide. The results show that the vinegar residue biomass carbon material prepared by the present invention has obvious electrochemical signal response to hydrogen peroxide analysis.

[0042] from Figure 4 It can be seen that Figure 4 a shows the detection of different concentrations of hydrogen peroxide by the vinegar residue-based biochar material prepared in Example 4. The results show that hydrogen peroxide as low as 10 μM can be detected by CV, and the detection range of the sensor is 10-4000 μM (Figure). Through calculation, it can be obtained that the detection limit of the sensor is as low as 0.5 μM.

[0043] from Figure 5 It can be seen that by testing different interferences to analyze the selectivity of the electrode modified by vinegar residue-based biomass carbon material for detecting hydrogen peroxide, the sensor has the highest oxidation current response to hydrogen peroxide (H2O2), and has the highest response to 10 times the concentration of uric acid (UA) and potassium ions (K + ) Nitrite ion (NO2 - ) and glucose (Glu) had almost no response, which proved that the material had excellent anti-interference ability and could still maintain a rapid response to hydrogen peroxide in the presence of interfering substances.

Claims

1. A method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material, characterized in that: The following steps are involved: S1, washing, drying, crushing and sieving the solid waste vinegar residue to obtain clean vinegar residue powder; S2. Carbonizing the vinegar residue powder under an inert atmosphere to obtain carbonized vinegar residue; S3, mixing the carbonized vinegar residue in a certain amount of hot alkaline solution for activation, and obtaining hot alkali modified waste vinegar residue-based biomass carbon material through aging, centrifugation, washing, drying and grinding.

2. The method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material according to claim 1, characterized in that: The hot alkaline solution in step S3 is potassium hydroxide or potassium carbonate solution, and the mass fraction of the hot alkaline solution is 10%-30%; the mass ratio of the alkali used to the carbonized vinegar residue is 10:

1.

3. The method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material according to claim 2, characterized in that: The temperature of the hot alkaline solution in step S3 is 60°C to 100°C.

4. The method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material according to claim 3, characterized in that: The activation time in step S3 is 1 to 3 h, and the aging time is 24 h.

5. The method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material according to claim 4, characterized in that: The centrifugal speed in step S3 is 8000 rpm - 11000 rpm, and the time is 10 min.

6. The method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material according to claim 1, characterized in that: The carbonization heating rate is 2°C / min~5°C / min; the carbonization temperature is 600°C~900°C; and the carbonization time is 1~3 h.

7. The method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material according to claim 1, characterized in that: The drying temperature in step S1 is 60-110° C.; the sieving mesh size is 80-200 mesh.

8. The method for preparing a hot alkali modified waste vinegar residue-based biomass carbon material according to claim 1, characterized in that: The inert atmosphere is any one of argon or nitrogen.

9. A thermal alkali modified waste vinegar residue-based biomass carbon material, characterized in that: The hot alkali modified waste vinegar residue-based biomass carbon material is prepared by any one of the preparation methods of claim 1 to claim 8.

10. An application of a thermal alkali-modified waste vinegar residue-based biomass carbon material, wherein the thermal alkali-modified waste vinegar residue-based biomass carbon material prepared by any one of claims 1 to 8 is applied to the preparation of a working electrode for an electrochemical biosensor.

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