A nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, its preparation method and application

Abstract

This invention proposes a nitrogen-oxygen co-doped capacitor carbon based on antibiotic fermentation residue, its preparation method, and its application, belonging to the field of capacitor technology. The process includes: drying and pulverizing antibiotic fermentation residue, adding a mixed acid for impregnation, filtering, washing, and drying to obtain pretreated residue; mixing the pretreated residue with ammonium chloride in water, mixing evenly, hydrothermal reaction, filtering, washing, and drying to obtain pre-reacted residue; mixing the pre-reacted residue with sodium carbonate evenly to obtain a mixed powder, pre-carbonizing it in stages, and cooling to obtain a pre-carbonized material; mixing the pre-carbonized material with an alkali evenly, activating it by heating, cooling, and washing to neutrality to obtain a carbonized material; impregnating the carbonized material in hydrogen peroxide, filtering, calcining by heating, cooling to room temperature, washing, and drying to obtain the antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon, which has the characteristics of high specific surface area and in-situ nitrogen-oxygen co-doping. The capacitor prepared from this carbon has a specific capacitance >200 F / g and a cycle retention rate >95% after 10,000 cycles.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, specifically to a nitrogen-oxygen co-doped capacitor carbon based on antibiotic fermentation residue, its preparation method, and its application. Background Technology

[0002] Currently, major antibiotics, including macrolides (erythromycin, azithromycin, etc.), β-lactams (cephalosporins, penicillins, etc.), tetracyclines (tetracycline, oxytetracycline, etc.), and aminoglycosides (streptomycin, gentamicin, etc.), are all produced using microbial fermentation processes, generating over 2 million tons of antibiotic fermentation residue annually. This residue mainly consists of mycelium, residual culture medium, and incompletely extracted antibiotics. The residual antibiotics can induce the production of resistance genes, promoting bacterial resistance. Improper handling can easily lead to the spread of drug-resistant bacteria, posing a serious threat to the ecological environment and human health. Given its potential hazards, my country included antibiotic fermentation residue in the "List of Hazardous Wastes" in 2008.

[0003] Methods for treating and disposing of antibiotic bacterial residue include incineration, landfill, high-temperature and high-pressure hydrolysis, composting, anaerobic digestion, as well as ionizing irradiation, microwave treatment, alkaline treatment, and pyrolysis carbonization. Incineration and sanitary landfill are traditional methods for treating hazardous waste. Antibiotic bacterial residue has a high water content and low calorific value, requiring external fuel during incineration, resulting in high treatment costs. Landfilling bacterial residue occupies a large amount of land, and the leachate produced by the decomposition and liquefaction of the residue can pollute groundwater. Other methods such as high-temperature hydrolysis, hydrothermal treatment, and anaerobic digestion are difficult to completely eliminate antibiotic pollution and usually require further treatment such as drying. Therefore, pyrolysis carbonization technology has become a current research hotspot due to its ability to achieve synergistic harmlessness and resource recovery.

[0004] In recent years, significant progress has been made in the research of preparing supercapacitor electrode materials using biomass. Chinese invention patent application CN119786276A discloses a supercapacitor carbon based on waste traditional Chinese medicine residue, its preparation method, and its application. The preparation method includes the following steps: Step 1, hydrothermal carbonization of traditional Chinese medicine residue powder to obtain hydrothermal carbon; Step 2, high-temperature activation of the hydrothermal carbon after mixing with KOH; Step 3, washing the activated sample until neutral, drying, acid washing, and drying again. The specific surface area of ​​the supercapacitor carbon ranges from 510.60 to 2060.21 m². 2 Between / g. However, this technical approach has the following problems:

[0005] (1) Insufficient adaptability to organic supercapacitors. Most commercially available supercapacitors use organic electrolytes (such as Et4NBF4 / PC), which have large solvated ion sizes (>1nm), requiring electrode materials with more developed mesoporous or macroporous structures. Existing research using Chinese herbal medicine residues as raw materials focuses on aqueous systems, where the micropores (<1nm) are difficult to utilize effectively in organic systems, leading to a significant decrease in specific capacitance.

[0006] (2) The advantages of in-situ doping of raw materials with high heteroatoms were not fully utilized. The nitrogen and oxygen content of Chinese herbal medicine residue is limited, and its capacitance improvement mainly depends on the physical double layer, with little contribution from pseudocapacitance. In contrast, antibiotic fermentation residue is rich in protein, polysaccharides and other components, and has a high natural content of nitrogen and oxygen elements, which has the potential for in-situ self-doping, and can effectively improve the surface wettability of carbon materials and provide additional Faraday capacitance.

[0007] (3) Lack of optimized activation process systems for raw materials with high volatile matter and high ash content. The volatile matter content of antibiotic fermentation residue is as high as 60% or more, while the fixed carbon content is only about 13%, which is significantly different from coconut shell (fixed carbon > 20%) or traditional Chinese medicine residue (mainly wood fiber). The violent release of high volatile matter during the activation process will interfere with the pore-forming reaction of KOH. The inorganic salts in the high ash content may act as templates to promote pore formation or consume activators. Existing technologies do not provide optimization guidance for key parameters such as alkali-to-carbon ratio and pre-carbonization method for such special raw materials, which easily leads to the dilemma of insufficient activation or pore collapse.

[0008] Therefore, there is an urgent need to develop a high-performance capacitor carbon preparation method that takes into account the characteristics of antibiotic fermentation residue raw materials, is suitable for organic supercapacitors, and has both ultra-high specific surface area and excellent heteroatom self-doping effect. Summary of the Invention

[0009] The purpose of this invention is to propose a nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, its preparation method, and its application. This invention adopts a multi-step synergistic process to solve the technical problems of difficult control of pore structure and low heteroatom utilization caused by high volatile matter and high ash content in antibiotic fermentation residue. It achieves the preparation of high-performance capacitive carbon with high specific surface area, in-situ nitrogen-oxygen co-doping, specific capacitance >200 F / g, and retention rate >95% after 10,000 cycles.

[0010] The technical solution of this invention is implemented as follows:

[0011] This invention provides a method for preparing nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, comprising the following steps:

[0012] S1. The antibiotic fermentation residue is dried, pulverized, impregnated with a mixed acid, filtered, washed, and dried to obtain pretreated residue. This invention first uses a mixed acid (including hydrochloric acid and nitric acid) for impregnation, which effectively removes a large amount of ash and some residual metal ions from the residue, avoiding the consumption of activators or pore blockage during subsequent high-temperature treatment. At the same time, acid treatment can destroy the cell wall structure of mycelium, increase the specific surface area and reaction sites, and provide a more uniform carbon precursor for subsequent nitrogen doping and activation.

[0013] S2. The pretreated bacterial residue is mixed with ammonium chloride and added to water. After thorough mixing, a hydrothermal reaction is carried out, followed by filtration, washing, and drying to obtain the pre-reacted bacterial residue. Traditional external nitrogen sources (such as urea and melamine) are usually added during the high-temperature carbonization / activation stage, which results in uneven nitrogen doping, poor thermal stability of nitrogen-containing functional groups, and easy escape at high temperatures. In this invention, under hydrothermal conditions, the NH3 produced by the decomposition of ammonium chloride reacts with the oxygen-containing functional groups (-COOH, -OH) in the bacterial residue to form stable nitrogen-containing structures (such as amides and amines). At the same time, this temperature can also promote Maillard reactions between the bacterial residues, which not only improves the nitrogen doping efficiency and uniformity but also allows the nitrogen element to be embedded more deeply in the carbon skeleton. After subsequent high-temperature activation, a certain nitrogen content can still be retained, effectively contributing pseudocapacitance.

[0014] S3. Mix the pre-reacted bacterial residue with sodium carbonate evenly, add water to adjust to a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material; This invention creatively blends sodium carbonate with pre-reacted bacterial residue, and the sodium carbonate dissolves in water to form a uniform sodium salt solution, which fully wets all the pores inside the hydrothermal carbon; After drying, the sodium salt is uniformly coated on the surface of the carbon skeleton in a nano-scale film and embedded in the internal pores, avoiding excessively high / low local salt concentrations in the solid-phase dry mixing, and ensuring that the subsequent activation reaction proceeds synchronously throughout the entire process. The carbon precursor is initially physically activated in the range of 200-500℃, and some volatile organic compounds decompose and co-escape, forming micropores / mesopores. In the range of 350-500℃, protein peptide bonds break and release nitrogen-containing gases (NH3, amines), forming pyridine nitrogen and pyrrole nitrogen precursors in the carbon skeleton. The temperature is further increased to 500-700℃ to promote aromatization and polycondensation. Under the synergistic effect of sodium carbonate, sodium carbonate and Ca / Mg in the residual ash of the bacterial residue form a low-melting-point eutectic salt system. This molten salt acts as a hard template to directionally etch uniform mesopores in the carbon skeleton, forming a preliminary microporous structure, and obtaining the pre-carbonized material.

[0015] S4. Mix the pre-carbonized material with alkali evenly, heat to activate, cool to room temperature, and wash until neutral to obtain carbonized material. This invention uses Na2CO3 and alkali (NaOH or KOH) as co-activators to activate pre-carbonized material from antibiotic fermentation residue to prepare porous carbon. Conventional KOH-activated biomass carbon usually requires an alkali-to-carbon ratio >2 to obtain carbon materials with high specific surface area, which is energy-intensive and highly corrosive. Since the preceding steps have removed a large amount of inactive ash through acid washing and pre-constructed micro / mesoporous morphology with the assistance of sodium carbonate, the pre-carbonized material at this stage has extremely high reactivity. When the alkali-to-carbon ratio is only 0.5-1, KOH / NaOH can etch the carbon skeleton along the pre-generated pore depth.

[0016] S5. The carbonized material is impregnated in hydrogen peroxide, filtered, calcined, cooled to room temperature, washed, and dried to obtain nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue. The specific surface area of ​​the capacitive carbon is 2800-3200 m². 2 / g. Reaction with hydrogen peroxide converts the surface carbon groups into quinone / carboxyl groups. Further calcination removes unstable oxygen-containing groups, reduces side reactions in the organic electrolyte, and forms stable pseudocapacitive active sites, maximizing the effective specific surface area and ion accessibility.

[0017] As a further improvement of the present invention, the mixed acid in step S1 is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.1-0.2 mol / L and a nitric acid concentration of 0.2-0.4 mol / L; the immersion time is 1-3 h.

[0018] As a further improvement of the present invention, the mass ratio of the pretreated bacterial residue to ammonium chloride in step S2 is 10:0.2-0.5; the temperature of the hydrothermal reaction is 150-170℃ and the time is 4-6h.

[0019] As a further improvement of the present invention, the mass ratio of the pre-reacted bacterial residue to sodium carbonate in step S3 is 10:2-3; the conditions for the segmented heating pre-carbonization are: 200-350℃ for 1-2 hours, 350-500℃ for 1-2 hours, and 500-700℃ for 1-3 hours.

[0020] As a further improvement of the present invention, the mass ratio of the pre-carbonized material to the alkali in step S4 is 1:0.5-1, the alkali is NaOH or KOH, the heating activation temperature is 750-850℃, and the time is 1-3h.

[0021] As a further improvement of the present invention, the impregnation time in step S5 is 1-2 hours, the concentration of hydrogen peroxide is 30-50 wt%, the solid-liquid ratio of carbonized material to hydrogen peroxide is 1:3-5 g / mL, and the heating and calcination temperature is 400-500℃ for 1-3 hours.

[0022] The present invention further protects a nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue prepared by the above-mentioned preparation method.

[0023] This invention further protects the application of the above-mentioned antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitive carbon in the preparation of supercapacitors.

[0024] This invention further protects a supercapacitor, wherein the above-mentioned capacitor carbon, acetylene black and polytetrafluoroethylene are placed in anhydrous ethanol in a mass ratio of 80-90:5-15:3-7, the ethanol is evaporated, the mixture is pressed into a thin sheet, dried, and pressed onto nickel foam to form an electrode sheet. The electrolyte is Et4NBF4 / PC organic electrolyte. After the negative electrode shell, spring, gasket, negative electrode sheet, separator, positive electrode sheet and positive electrode shell are assembled in sequence, the supercapacitor is stamped to obtain the supercapacitor.

[0025] As a further improvement of the present invention, the specific capacitance of the supercapacitor is >200F / g, and the capacitance retention rate after 10,000 cycles is >95%.

[0026] The present invention has the following beneficial effects:

[0027] 1. This invention avoids the secondary pollution and resource waste caused by traditional incineration or landfill, and realizes the efficient, harmless and high-value utilization of antibiotic fermentation residue hazardous solid waste. Through multiple reaction steps, the antibiotic fermentation residue is transformed into high-value-added supercapacitor electrode material. At the same time, it contains almost no antibiotic residue, thus achieving both environmental and economic benefits.

[0028] 2. The present invention first uses a mixed acid impregnation of dilute hydrochloric acid and nitric acid, which can effectively remove a large amount of ash and some residual metal ions from the bacterial residue, avoiding the consumption of activator or pore blockage during subsequent high-temperature treatment; at the same time, acid treatment can destroy the cell wall structure of mycelium, increase the specific surface area and reaction sites, and provide a more uniform carbon precursor for subsequent nitrogen doping and activation.

[0029] 3. This invention achieves efficient and uniform in-situ nitrogen doping through the hydrothermal reaction of ammonium chloride. The appropriate hydrothermal reaction temperature promotes the Maillard reaction and forms a stable nitrogen-containing structure, which not only improves the doping efficiency and uniformity of nitrogen, but also allows nitrogen to be embedded deeper in the carbon skeleton. After subsequent high-temperature activation, a certain amount of nitrogen content can still be retained, effectively contributing to pseudocapacitance.

[0030] 4. This invention utilizes sodium carbonate in conjunction with a staged pre-carbonization process. The low-temperature stage removes residual moisture and low-molecular-weight organic matter, the medium-temperature stage involves the phased pyrolysis of proteins / polysaccharides, and the high-temperature stage involves aromatic condensation and shaping. This process avoids the collapse of the overall structure caused by the concentrated release of volatiles. At the same time, sodium carbonate and the Ca / Mg residue in the bacterial residue form a low-melting-point eutectic salt system. This molten salt acts as a hard template to directionally etch uniform mesopores in the carbon skeleton, thereby increasing the specific surface area of ​​the final carbon material.

[0031] 5. This invention uses sodium carbonate and alkali in synergistic treatment, which greatly reduces the amount of alkali used, thereby reducing equipment corrosion, lowering costs, and achieving economical and efficient deep pore formation.

[0032] 6. In this invention, the surface carbon groups are converted into quinone / carboxyl groups by subsequent reaction with hydrogen peroxide, and further calcination is carried out to remove unstable oxygen-containing groups, reduce side reactions in the organic electrolyte, maximize the effective specific surface area and ion accessibility, and form a stable pseudocapacitor.

[0033] 7. This invention introduces lone pair electrons through nitrogen-oxygen dual doping, with pyridine nitrogen (N-6) and pyrrole nitrogen (N-5) to change the electron cloud distribution of the carbon skeleton, generating an n-type conductivity effect and improving the intrinsic conductivity of the material. The carboxyl and phenolic hydroxyl groups can undergo reversible proton exchange reactions, contributing pseudocapacitance. The high content of oxygen functional groups significantly improves the wettability of carbon materials and increases the utilization rate of effective double-layer capacitance. There are hydrogen bond interactions and conjugation effects between nitrogen and oxygen functional groups, making nitrogen / oxygen-containing groups more stable during cycling and less prone to irreversible redox degradation, achieving a retention rate of >95% after 10,000 cycles. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 The following are SEM images of the capacitor carbon from Examples 1-3: (a) Example 1; (b) Example 2; (c) Example 3.

[0036] Figure 2 (a) Comparison of constant current charge-discharge curves of the capacitor carbon prepared in Examples 1-3 in 1 M Et4NBF4 / PC organic electrolyte (current density 0.5 A / g); (b) Rate performance curves of the capacitor carbon prepared in Example 3 at different current densities. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] This embodiment provides a method for preparing nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, comprising the following steps:

[0040] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 1h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.1mol / L and a nitric acid concentration of 0.2mol / L;

[0041] S2. Mix 10g of pretreated bacterial residue with 0.2g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 150℃ for 6h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0042] S3. Mix 10g of pre-reacted bacterial residue with 2g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize by heating in stages, and cool to room temperature to obtain pre-carbonized material;

[0043] The conditions for segmented heating and pre-carbonization are: 200℃ for 2 hours, 350℃ for 2 hours, and 700℃ for 1 hour.

[0044] S4. Mix 10g of pre-carbonized material with 5g of KOH evenly, heat to 750℃, activate for 3h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0045] S5. Add 10g of carbonized material to 30mL of 30wt% hydrogen peroxide, soak for 2h, filter, heat to 400℃, calcine for 3h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0046] Example 2

[0047] This embodiment provides a method for preparing nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, comprising the following steps:

[0048] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 3h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.2mol / L and a nitric acid concentration of 0.4mol / L;

[0049] S2. Mix 10g of pretreated bacterial residue with 0.5g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 170℃ for 4h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0050] S3. Mix 10g of pre-reacted bacterial residue with 3g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material;

[0051] The conditions for segmented heating and pre-carbonization are: 350℃ for 1 hour, 500℃ for 2 hours, and 550℃ for 3 hours.

[0052] S4. Mix 10g of pre-carbonized material with 10g of KOH evenly, heat to 850℃, activate for 1h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0053] S5. Add 10g of carbonized material to 50mL of 50wt% hydrogen peroxide, soak for 1h, filter, heat to 500℃, calcine for 1h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0054] Example 3

[0055] This embodiment provides a method for preparing nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, comprising the following steps:

[0056] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0057] S2. Mix 10g of pretreated bacterial residue with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0058] S3. Mix 10g of pre-reacted bacterial residue with 2.5g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material;

[0059] The conditions for segmented heating and pre-carbonization are: 250℃ for 1.5h, 400℃ for 1.5h, and 600℃ for 2h.

[0060] S4. Mix 10g of pre-carbonized material with 7g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0061] S5. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon. Figure 1 The images show SEM images of the capacitor carbon from Examples 1-3: (a) Example 1; (b) Example 3; (c) Example 2. As can be seen from the images, the capacitor carbon has formed pores of different sizes and is rich in pores.

[0062] Example 4

[0063] Compared with Example 3, the only difference is that the mass ratio of pre-carbonized material to KOH is 1:2.

[0064] Includes the following steps:

[0065] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0066] S2. Mix 10g of pretreated bacterial residue with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0067] S3. Mix 10g of pre-reacted bacterial residue with 2.5g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material;

[0068] The conditions for segmented heating and pre-carbonization are: 250℃ for 1.5h, 400℃ for 1.5h, and 600℃ for 2h.

[0069] S4. Mix 10g of pre-carbonized material with 20g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0070] S5. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0071] Comparative Example 1

[0072] Compared with Example 3, the only difference is that step S1 was not performed.

[0073] Includes the following steps:

[0074] S1. Dry and crush 10g of erythromycin fermentation residue, mix it with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reaction residue.

[0075] S2. Mix 10g of pre-reacted bacterial residue with 2.5g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material;

[0076] The conditions for segmented heating and pre-carbonization are: 250℃ for 1.5h, 400℃ for 1.5h, and 600℃ for 2h.

[0077] S3. Mix 10g of pre-carbonized material with 7g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0078] S4. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0079] Comparative Example 2

[0080] Compared with Example 3, the only difference is that step S2 was not performed.

[0081] Includes the following steps:

[0082] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0083] S2. Mix 10g of pretreated bacterial residue with 2.5g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material;

[0084] The conditions for segmented heating and pre-carbonization are: 250℃ for 1.5h, 400℃ for 1.5h, and 600℃ for 2h.

[0085] S3. Mix 10g of pre-carbonized material with 7g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0086] S4. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0087] Comparative Example 3

[0088] Compared with Example 3, the only difference is that sodium carbonate was not added in step S3.

[0089] Includes the following steps:

[0090] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0091] S2. Mix 10g of pretreated bacterial residue with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0092] S3. 10g of pre-reacted bacterial residue is heated and pre-carbonized in stages, then cooled to room temperature to obtain pre-carbonized material;

[0093] The conditions for segmented heating and pre-carbonization are: 250℃ for 1.5h, 400℃ for 1.5h, and 600℃ for 2h.

[0094] S4. Mix 10g of pre-carbonized material with 7g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0095] S5. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0096] Comparative Example 4

[0097] Compared with Example 3, the only difference is that segmented heating pre-carbonization was not performed in step S3, and the temperature was kept at 600°C for 5 hours.

[0098] Includes the following steps:

[0099] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0100] S2. Mix 10g of pretreated bacterial residue with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0101] S3. Mix 10g of pre-reacted bacterial residue with 2.5g of sodium carbonate evenly, add water to make a viscous consistency, dry, keep at 600℃ for 5h, and cool to room temperature to obtain pre-carbonized material;

[0102] S4. Mix 10g of pre-carbonized material with 7g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0103] S5. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0104] Comparative Example 5

[0105] Compared with Example 3, the only difference is that step S3 was not performed.

[0106] Includes the following steps:

[0107] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0108] S2. Mix 10g of pretreated bacterial residue with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0109] S3. Mix 10g of pre-reacted bacterial residue with 7g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0110] S4. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0111] Comparative Example 6

[0112] Compared with Example 3, the only difference is that KOH was not added in step S4.

[0113] Includes the following steps:

[0114] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0115] S2. Mix 10g of pretreated bacterial residue with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0116] S3. Mix 10g of pre-reacted bacterial residue with 2.5g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material;

[0117] The conditions for segmented heating and pre-carbonization are: 250℃ for 1.5h, 400℃ for 1.5h, and 600℃ for 2h.

[0118] S4. Heat 10g of pre-carbonized material to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material;

[0119] S5. Add 10g of carbonized material to 40mL of 40wt% hydrogen peroxide, soak for 1.5h, filter, heat to 450℃, calcine for 2h, cool to room temperature, wash, and dry to obtain antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0120] Comparative Example 7

[0121] Compared with Example 3, the only difference is that step S5 was not performed.

[0122] Includes the following steps:

[0123] S1. Dry and crush 10g of erythromycin fermentation residue, add 100mL of mixed acid and soak for 2h, filter, wash and dry to obtain pretreated residue; the mixed acid is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.15mol / L and a nitric acid concentration of 0.3mol / L;

[0124] S2. Mix 10g of pretreated bacterial residue with 0.3g of ammonium chloride and add it to 50mL of water. Mix well and react hydrothermally at 160℃ for 5h. Filter, wash and dry to obtain pre-reacted bacterial residue.

[0125] S3. Mix 10g of pre-reacted bacterial residue with 2.5g of sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize in stages by heating, and cool to room temperature to obtain pre-carbonized material;

[0126] The conditions for segmented heating and pre-carbonization are: 250℃ for 1.5h, 400℃ for 1.5h, and 600℃ for 2h.

[0127] S4. Mix 10g of pre-carbonized material with 7g of KOH evenly, heat to 800℃, activate for 2h, cool to room temperature, wash until neutral, and obtain carbonized material, which is antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon.

[0128] Test Example 1

[0129] The specific surface area of ​​the antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitive carbon prepared in Examples 1-4 and Comparative Examples 1-7 was determined using an automated gas adsorption analyzer (Autosorb-iQ-MP). The results are shown in Table 1.

[0130] Table 1

[0131]

[0132] As shown in the table above, the antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitive carbon prepared in Examples 1-3 of this invention has a high specific surface area. Ideal electric double-layer capacitors primarily store energy via electrostatic energy storage, mainly relying on the physical adsorption and desorption of electrolyte ions in the solution on the surface of the activated carbon electrode. Therefore, theoretically, the capacity of porous carbon electrode materials is directly proportional to their specific surface area; thus, increasing the specific surface area is one of the main ways to improve energy storage density. In Example 4, the mass ratio of KOH to pre-carbonized material was 2:1, and the increase in specific surface area was not significant, indicating that a high proportion of KOH is not required to obtain capacitive carbon with a high specific surface area.

[0133] Test Example 2

[0134] The antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon, acetylene black, and polytetrafluoroethylene prepared in Examples 1-4 and Comparative Examples 1-8 were placed in anhydrous ethanol at a mass ratio of 85:10:5. The ethanol was evaporated, the carbon was pressed into thin sheets, dried, and pressed onto nickel foam to form electrode sheets. The electrolyte was 1 mol / L Et4NBF4 / PC organic electrolyte. After the negative electrode shell, spring sheet, gasket, negative electrode sheet, separator, positive electrode sheet, and positive electrode shell were assembled in sequence, the supercapacitor was stamped to obtain the supercapacitor.

[0135] The electrochemical performance of the capacitor was tested, and the results are shown in Table 2.

[0136] Table 2

[0137]

[0138] As can be seen from the table above, the capacitors made from the antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitor carbon prepared in Examples 1-3 of this invention have good electrochemical performance.

[0139] Figure 2 In the figure, (a) is a comparison of the constant current charge-discharge curves (current density 0.5 A / g) of the capacitor carbon prepared in Examples 1-3 in 1 M Et4NBF4 / PC organic electrolyte; (b) is a curve showing the rate performance of the capacitor carbon prepared in Example 3 at different current densities. As can be seen from the figure, all three curves are highly symmetrical isosceles triangles with no obvious voltage plateau, which is typical of carbon-based double-layer capacitors. At the same time, the curves exhibit slight circular distortion, proving that the material has a pseudocapacitive contribution. The capacitor carbon prepared in Example 3 has the longest charge-discharge time, the best specific capacitance among the three samples, and excellent rate performance.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, characterized in that, Includes the following steps: S1. Dry the antibiotic fermentation residue, crush it, add it to a mixed acid for soaking, filter, wash, and dry to obtain pretreated residue; S2. The pretreated bacterial residue is mixed with ammonium chloride and added to water. The mixture is stirred evenly, subjected to hydrothermal reaction, filtered, washed, and dried to obtain the pre-reacted bacterial residue. S3. Mix the pre-reacted bacterial residue with sodium carbonate evenly, add water to make a viscous consistency, dry, pre-carbonize by heating in stages, and cool to room temperature to obtain pre-carbonized material; S4. Mix the pre-carbonized material with alkali evenly, heat to activate, cool to room temperature, and wash until neutral to obtain the carbonized material; S5. The carbonized material is added to hydrogen peroxide for impregnation, filtered, heated for calcination, cooled to room temperature, washed, dried, and an antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitive carbon is prepared, wherein the specific surface area of the capacitive carbon is 2800-3200 m 2 / g.

2. The preparation method according to claim 1, characterized in that, The mixed acid mentioned in step S1 is a mixture of hydrochloric acid and nitric acid, with a hydrochloric acid concentration of 0.1-0.2 mol / L and a nitric acid concentration of 0.2-0.4 mol / L; the soaking time is 1-3 hours.

3. The preparation method according to claim 1, characterized in that, In step S2, the mass ratio of the pretreated bacterial residue to ammonium chloride is 10:0.2-0.5; the hydrothermal reaction temperature is 150-170℃ and the time is 4-6h.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the pre-reacted bacterial residue to sodium carbonate in step S3 is 10:2-3; the conditions for the segmented heating pre-carbonization are: 200-350℃ for 1-2 hours, 350-500℃ for 1-2 hours, and 500-700℃ for 1-3 hours.

5. The preparation method according to claim 1, characterized in that, In step S4, the mass ratio of the pre-carbonized material to the alkali is 1:0.5-1, the alkali is NaOH or KOH, and the heating activation temperature is 750-850℃ for 1-3 hours.

6. The preparation method according to claim 1, characterized in that, In step S5, the soaking time is 1-2 hours, the concentration of hydrogen peroxide is 30-50 wt%, the solid-liquid ratio of carbonized material to hydrogen peroxide is 1:3-5 g / mL, and the heating and calcination temperature is 400-500℃ for 1-3 hours.

7. A nitrogen-oxygen co-doped capacitive carbon based on antibiotic fermentation residue, prepared by the method according to any one of claims 1-6.

8. The application of the antibiotic fermentation residue-based nitrogen-oxygen co-doped capacitive carbon as described in claim 7 in the preparation of supercapacitors.

9. A supercapacitor, characterized in that, The capacitor carbon, acetylene black, and polytetrafluoroethylene described in claim 7 are placed in anhydrous ethanol at a mass ratio of 80-90:5-15:3-7. The ethanol is evaporated, the mixture is pressed into a thin sheet, dried, and pressed onto nickel foam to form an electrode sheet. The electrolyte is Et4NBF4 / PC organic electrolyte. After the negative electrode shell, spring sheet, gasket, negative electrode sheet, separator, positive electrode sheet, and positive electrode shell are assembled in sequence, they are stamped to form a supercapacitor.

10. The supercapacitor according to claim 9, characterized in that, The supercapacitor has a specific capacitance of >200F / g and a capacitance retention rate of >95% after 10,000 cycles.

Images