Preparation method of biomass carbon source based on kitchen waste

Abstract

The application provides a preparation method of biomass carbon source based on kitchen waste, which comprises the following steps: crushing the kitchen waste, separating oil and fat, modifying part of sugarcane residue adsorption slurry by using acid and ethanol, mixing the modified part of sugarcane residue adsorption slurry with the remaining sugarcane residue, and then fermenting, finally removing oil, and separating solid and liquid to obtain biomass carbon source liquid, and activating the residue into porous carbon material. The application fully recycles the organic matter in the kitchen waste and converts it into high-value biomass carbon source. The kitchen waste is combined with the sugarcane residue, on the one hand, the modified sugarcane residue can remove the salt in the kitchen waste, on the other hand, the solid residue obtained by degrading the sugarcane residue by fermentation together with the slurry is activated to obtain a porous carbon material, the obtained biomass carbon source liquid can be used for fungal fermentation to produce yeast protein and ethanol synchronously and is not affected by the acid and alkali conditions and high ammonia nitrogen of the kitchen waste, and can be used for biological fermentation more conveniently, and has the prospect of large-scale application.

Description

Technical Field

[0001] This invention relates to the field of food waste treatment, and more specifically to a method for preparing a biomass carbon source based on food waste. Background Technology

[0002] Food waste mainly comes from the catering industry, institutional canteens, and family kitchens. Its composition is complex, primarily including leftover rice and flour products, vegetables, animal and vegetable oils, meat and bones, etc., and is characterized by high moisture content, high oil content, high salt content, and easy decomposition. Currently, my country mainly uses anaerobic fermentation technology for food waste treatment. However, due to the diverse types of foreign matter in food waste, its varying forms and properties, and the low yield of resource-based products such as biogas and crude oil, food waste treatment faces problems such as complex technology, high operating costs, and low resource value.

[0003] Meanwhile, the demand for biomass carbon sources continues to grow in fields such as microbial fermentation and wastewater treatment. In particular, wastewater treatment plants generally suffer from an imbalance of nutrients in their influent. Due to insufficient carbon sources for denitrification, deep denitrification of wastewater mainly relies on external carbon sources. Currently, commonly used carbon sources include methanol, sodium acetate, and glucose, but these generally suffer from high costs and unsustainable resource availability.

[0004] Therefore, developing biomass carbon sources from food waste can solve both the food waste treatment problem and the high cost of adding external carbon sources to wastewater treatment plants, thus possessing both environmental governance and resource recycling value. However, current technologies and processes for preparing carbon sources from food waste suffer from drawbacks such as complex preparation methods, long processing times, poor component separation, high costs, and insufficient carbon source purity and stability. These limitations fail to meet the demands for external carbon sources that offer high content, easy biodegradability, rapid reaction speed, good biological adaptability, and low cost. Furthermore, high salinity severely inhibits fermenting microorganisms and also inhibits the application of the prepared biomass carbon source liquid to fungal fermentation. Therefore, further improvements and development are needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies and solve the aforementioned problems, a method for preparing biomass carbon sources based on kitchen waste is proposed, and the following technical solution is provided:

[0006] A method for preparing a biomass carbon source based on kitchen waste includes the following steps:

[0007] S1: Grind the kitchen waste to a particle size ≤5mm;

[0008] S2: Mix the chopped kitchen waste with water, and then separate the grease and slurry after heat treatment;

[0009] S3: Sugarcane bagasse is divided into sugarcane bagasse A and sugarcane bagasse B. Sugarcane bagasse A is crushed to a particle size of 1-1.5cm, then soaked in an acid solution and washed with water until neutral. After drying, it is soaked in an ethanol solution and microwaved to obtain modified sugarcane bagasse. The slurry is mixed and stirred with the modified sugarcane bagasse and then filtered to obtain the filtered slurry.

[0010] S4: The filtered slurry is mixed with sugarcane bagasse B with a particle size ≤5mm and then added to the fermentation device with microbial fermentation aid for fermentation and degradation.

[0011] S5: The fermented and degraded slurry is reheated and then subjected to secondary oil removal to obtain the oil-removed slurry.

[0012] S6: The oil-removed slurry is subjected to solid-liquid separation to obtain biomass carbon source liquid and solid residue;

[0013] S7: Mix the solid residue with the activator to activate it and obtain porous carbon material.

[0014] Furthermore, in step S2, the solid-liquid ratio of the shredded kitchen waste to water is 1:(2-5).

[0015] Furthermore, in step S3, the mass ratio of sugarcane bagasse A to kitchen waste is 2-4:7-10.

[0016] Furthermore, in step S3, the acid solution is an oxalic acid solution with a mass concentration of 3-5%, and the person is immersed in the oxalic acid solution for 2-3 hours. The microwave treatment power is 800-1000W, and the microwave treatment time is 5-10 minutes.

[0017] Furthermore, in step S2, the heat treatment temperature is 40-60℃ and the time is 10-60 min.

[0018] Furthermore, in step S2, a centrifugal separation device is used to separate the oil and slurry. The centrifugal separation speed is 3000-5000 r / min and the time is 5-20 min.

[0019] Furthermore, the microbial fermentation aid mentioned in step S4 is potassium dihydrogen phosphate or magnesium sulfate, and the amount of microbial fermentation aid added is 0.5%-1% of the slurry mass.

[0020] Furthermore, in step S4, nano-catalytic materials are added to the fermentation device, and the amount of nano-catalytic materials added is 0.1%-0.3% of the slurry mass.

[0021] Furthermore, in step S4, the fermentation and degradation time is 6-24 hours, with stirring every 10-120 minutes, controlling the stirring speed at 100-200 r / min and the stirring time at 5-10 minutes.

[0022] Furthermore, in step S4, the amount of bagasse B used is 60-80% of the mass of the filtered slurry.

[0023] Due to the adoption of the above technical solutions, the beneficial technical effects of the present invention are as follows:

[0024] 1. This invention fully recovers the organic matter in kitchen waste and converts it into a high-value biomass carbon source. Furthermore, by combining sugarcane bagasse with kitchen waste, on the one hand, the modified sugarcane bagasse can remove the salt in the kitchen waste, and on the other hand, the solid residue obtained after the sugarcane bagasse is fermented and degraded together with the slurry can be activated to obtain porous carbon material. The resulting biomass carbon source liquid can be fermented by fungi to simultaneously produce yeast protein and ethanol, and is not affected by the acid and alkaline conditions and high ammonia nitrogen of kitchen waste. It can be carried out in a relatively convenient way and has the prospect of large-scale application.

[0025] 2. The carbon source of this invention has excellent quality. Through component separation, catalytic activation and multi-stage purification, the effective organic matter (calculated as COD) content in the carbon source is ≥60000mg / L. The composition is stable and can replace conventional carbon sources such as glucose and sodium acetate. It is suitable for scenarios such as microbial fermentation and denitrification.

[0026] 3. Full resource utilization: The oil in kitchen waste is processed into biomass-based liquid fuel, and the solid residue is processed into dispersed porous carbon materials, realizing the full resource utilization of kitchen waste without generating any waste and avoiding secondary pollution;

[0027] 4. It reduces the pollution risks of landfilling and incineration of kitchen waste, while the preparation process does not cause secondary pollution, thus contributing to the circular economy and green development. Attached Figure Description

[0028] Figure 1 This is a schematic flowchart of a method for preparing a biomass carbon source based on kitchen waste according to the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application.

[0030] A method for preparing a biomass carbon source based on kitchen waste includes the following steps:

[0031] S1: Crush the kitchen waste to a particle size ≤5mm. Crushing the kitchen waste into small particles ensures thorough contact between the kitchen waste and water during subsequent mixing.

[0032] S2: The chopped kitchen waste is mixed with water and then heat-treated to separate the grease and slurry. The separated grease is collected for reuse, while the slurry proceeds to the next processing step.

[0033] S3: Sugarcane bagasse is separated into bagasse A and bagasse B. Bagasse A is crushed to a particle size of 1-1.5 cm, then soaked in an acid solution, washed with water until neutral, dried, and then soaked in an ethanol solution for microwave treatment to obtain modified bagasse. The slurry is mixed with the modified bagasse and then filtered to obtain the filtered slurry. The particle size of the modified bagasse (1-1.5 cm) is much larger than the fine organic particles in the slurry, avoiding the loss of organic particles in the slurry during filtration. The porous structure of the bagasse provides attachment sites for fermentation bacteria, thereby accelerating the reaction rate. Meanwhile, the fermented carbon source liquid from food waste is rich in volatile fatty acids (VFAs), alcohols, and various trace elements. Small organic molecules such as VFAs can effectively penetrate the dense fibrous structure of sugarcane bagasse. During the subsequent carbonization and activation stage, these embedded organic compounds preferentially decompose or gasify, helping to form a richer and more developed pore structure, thus significantly increasing the specific surface area of ​​activated carbon. Trace elements such as nitrogen, phosphorus, and sulfur are adsorbed by the sugarcane bagasse fibers during the modification process. During high-temperature carbonization, these elements are chemically bonded into the carbon skeleton, achieving in-situ heteroatom doping. Nitrogen-doped carbon materials possess excellent surface polarity, electronic conductivity, and catalytic activity, greatly enhancing the adsorption capacity and catalytic performance of activated carbon for pollutants.

[0034] S4: The filtered slurry is mixed with sugarcane bagasse B with a particle size ≤5mm, and then added to the fermentation device along with a microbial fermentation aid for fermentation and degradation. Fermentation produces high-value biomass carbon source liquid and stabilized solid residue.

[0035] S5: The fermented and degraded slurry is reheated and subjected to a second oil removal process to obtain an oil-removed slurry. This second oil removal ensures that trace amounts of oil in the slurry are removed. The resulting oil, along with the oil separated in S2, can be used to prepare biomass-based liquid fuel.

[0036] S6: The degreased slurry is subjected to solid-liquid separation to obtain biomass carbon source liquid and solid residue. The separated biomass carbon source liquid has an effective organic matter (COD) content ≥60000mg / L, stable composition, and can replace conventional carbon sources such as glucose and sodium acetate. It is suitable for scenarios such as microbial fermentation and denitrification. The obtained biomass carbon source liquid can be fermented by fungi to simultaneously produce yeast protein and ethanol and is not affected by the acid and alkaline conditions and high ammonia nitrogen of kitchen waste. It can be easily carried out for biological fermentation and has the prospect of large-scale application.

[0037] S7: Solid residue is mixed with an activator to obtain porous carbon material. The resulting porous carbon material has abundant surface functional groups. The oxygen- and nitrogen-containing functional groups introduced from food waste greatly enhance the surface chemical activity of the activated carbon, enabling it to have extremely high adsorption capacity and adsorption rate for heavy metal ions and organic pollutants through complexation, ion exchange, hydrogen bonding, and other interactions.

[0038] Specifically, in step S2, the solid-liquid ratio of the crushed kitchen waste to water is 1:(2-5). This 1:(2-5) solid-liquid ratio during heat treatment represents the maximum range of kitchen waste that water can accommodate. Too much kitchen waste will push the water's carrying capacity to its limit, preventing the formation of a slurry; too little kitchen waste will lead to water waste waste, and the resulting slurry will contain too little biomass carbon source, burdening subsequent processing.

[0039] Specifically, in step S3, the mass ratio of sugarcane bagasse A to kitchen waste is 2-4:7-10. The mixing of modified sugarcane bagasse with kitchen waste slurry at a mass ratio of 2-4:7-10 can effectively reduce the salt content in the slurry through adsorption, thereby reducing the load and difficulty for subsequent fermentation and degradation.

[0040] Specifically, in step S3, the acid solution is an oxalic acid solution with a mass concentration of 3-5%. The bagasse is immersed in the oxalic acid solution for 2-3 hours. The microwave treatment power is 800-1000W, and the microwave treatment time is 5-10 minutes. Oxalic acid treatment can effectively hydrolyze and destroy some of the cellulose and lignin in the bagasse, making the originally dense fiber structure loose and porous. Microwave treatment in the ethanol solution generates a localized thermal effect, further increasing the porosity and specific surface area of ​​the bagasse. This loose and porous structure can improve the adsorption of impurities such as salt in the pulp by the bagasse.

[0041] Specifically, in step S2, the heat treatment temperature is 40-60℃ and the time is 10-60 min.

[0042] Specifically, in step S2, a centrifugal separator is used to separate the grease and slurry. The centrifugal separation speed is 3000-5000 r / min, and the time is 5-20 min. The centrifugal separation speed of 3000-5000 r / min and the time of 5-20 min can ensure that the grease and slurry are fully separated.

[0043] Specifically, the microbial fermentation aid mentioned in step S4 is potassium dihydrogen phosphate or magnesium sulfate, and the amount of microbial fermentation aid added is 0.5%-1% of the slurry mass. An appropriate amount of potassium dihydrogen phosphate or magnesium sulfate provides additional nutrients and trace elements for microbial fermentation.

[0044] Specifically, in step S4, nano-catalyst materials are added to the fermentation device, with the amount of nano-catalyst materials added being 0.1%-0.3% of the slurry mass. Appropriate amounts of nano-catalyst materials possess a large specific surface area and high reactivity, making them a crucial element in efficient fermentation.

[0045] Specifically, in step S4, the fermentation and degradation time is 6-24 hours, with stirring every 10-120 minutes, controlling the stirring speed at 100-200 r / min and the stirring time at 5-10 minutes. Controlling the stirring interval and stirring time during fermentation ensures that the sugarcane bagasse and slurry are thoroughly mixed without creating temperature or concentration gradients.

[0046] Specifically, in step S4, the amount of bagasse B is 60-80% of the mass of the filtered slurry. Controlling the amount of bagasse B ensures that the bagasse contributes to the excellent performance of the porous carbon material subsequently produced.

[0047] The specific process of this invention is as follows: Figure 1 As shown:

[0048] Household food waste is transported to a sorting platform for screening. Through a combination of manual and mechanical sorting, solid impurities such as metals and ceramic fragments, as well as non-biodegradable substances like plastics, are separated, ensuring the purity of the organic raw materials for subsequent processing. The food waste items S1-S7 below are all pre-sorted, purified food waste.

[0049] The kitchen waste is crushed to a particle size of ≤5mm; crushing the kitchen waste into small particles makes it easier for the kitchen waste to come into full contact with water during subsequent mixing.

[0050] The chopped kitchen waste is mixed with water at a solid-liquid ratio of 1:(2-5) and subjected to heat treatment for 10-60 minutes at a temperature of 40-60℃. After heat treatment, the grease and slurry are separated by centrifugation at a speed of 3000-5000 r / min for 5-20 minutes.

[0051] Sugarcane bagasse is divided into bagasse A and bagasse B. Bagasse A is crushed to a particle size of 1-1.5 cm and then soaked in a 3-5% oxalic acid solution for 2-3 hours. After soaking, it is washed with water until neutral, dried, and then soaked in an ethanol solution for microwave treatment at 800-1000W for 5-10 minutes to obtain modified bagasse. The modified bagasse at a mass ratio of 2-4:7-10 is mixed with kitchen waste slurry and stirred before filtration to obtain the filtered slurry.

[0052] The filtered slurry is mixed with 60%-80% (by weight) of sugarcane bagasse B (with a particle size ≤5mm), and then added to a fermentation apparatus along with 0.5%-1% (by weight) of potassium dihydrogen phosphate or magnesium sulfate. 0.1%-0.3% (by weight) of nano-catalyst material is also added to the fermentation apparatus for fermentation degradation. The mixture is stirred every 10-120 minutes, with a stirring speed of 100-200 rpm for 5-10 minutes, and the fermentation time is 6-24 hours.

[0053] The fermented and degraded slurry is reheated and then subjected to a second oil removal process to obtain an oil-removed slurry.

[0054] The deoiled slurry is subjected to solid-liquid separation to obtain biomass carbon source liquid and solid residue.

[0055] Porous carbon materials are obtained by mixing solid residues with an activator and activating them.

[0056] Example 1

[0057] S1: Grind the kitchen waste to a particle size ≤5mm;

[0058] S2: The chopped kitchen waste is mixed with water and then heat-treated to separate the grease and slurry. The solid-liquid ratio of the chopped kitchen waste to water is 1:3, and the mixture is heat-treated for 40 minutes at 50°C. After heat treatment, a centrifuge at 4000 r / min is used to separate the grease and slurry for 15 minutes.

[0059] S3: Sugarcane bagasse is divided into bagasse A and bagasse B. Bagasse A is crushed to a particle size of 1.5 cm and then soaked in a 4% oxalic acid solution for 2.5 hours. After soaking, it is washed with water until neutral, dried, and then soaked in an ethanol solution for microwave treatment at 900W for 8 minutes to obtain modified bagasse. The modified bagasse is mixed with kitchen waste slurry at a mass ratio of 3:8 and then filtered to obtain the filtered slurry.

[0060] S4: The filtered slurry is mixed with 70% sugarcane bagasse B (particle size ≤ 5mm by weight), and then added to the fermentation device along with 1% potassium dihydrogen phosphate or magnesium sulfate by weight. 0.2% nano-catalyst material by weight is also added to the fermentation device for fermentation degradation. The fermentation device is stirred every 60 minutes, with a stirring speed of 150 r / min and a stirring time of 8 minutes. The fermentation time is 18 hours.

[0061] S5: The fermented and degraded slurry is reheated and then subjected to secondary oil removal to obtain the oil-removed slurry.

[0062] S6: The oil-removed slurry is subjected to solid-liquid separation to obtain biomass carbon source liquid and solid residue;

[0063] S7: Mix the solid residue with the activator to activate it and obtain porous carbon material.

[0064] Example 2

[0065] S1: Grind the kitchen waste to a particle size ≤5mm;

[0066] S2: Mix the chopped kitchen waste with water and perform heat treatment to separate the grease and slurry; mix the chopped kitchen waste with water at a solid-liquid ratio of 1:5 and perform heat treatment for 60 minutes at 60℃. After heat treatment, use a centrifuge at 5000 r / min for 20 minutes to separate the grease and slurry.

[0067] S3: Sugarcane bagasse is divided into sugarcane bagasse A and sugarcane bagasse B. Sugarcane bagasse A is crushed to a particle size of 1.5 cm and then soaked in a 5% oxalic acid solution for 3 hours. After soaking, it is washed with water until neutral, dried, and then soaked in an ethanol solution for microwave treatment at 1000W for 10 minutes to obtain modified sugarcane bagasse. The modified sugarcane bagasse at a mass ratio of 4:7 is mixed with kitchen waste slurry and stirred before filtration to obtain the filtered slurry.

[0068] S4: The filtered slurry is mixed with 80% of the slurry mass of sugarcane bagasse B (with a particle size ≤5mm), and then added to the fermentation device along with 0.5% of the slurry mass of potassium dihydrogen phosphate or magnesium sulfate. 0.3% of the slurry mass of nano-catalyst material is also added to the fermentation device for fermentation degradation. The fermentation device is stirred every 120 minutes, with a stirring speed of 200 rpm for 10 minutes, and the fermentation time is 24 hours.

[0069] S5: The fermented and degraded slurry is reheated and then subjected to secondary oil removal to obtain the oil-removed slurry.

[0070] S6: The oil-removed slurry is subjected to solid-liquid separation to obtain biomass carbon source liquid and solid residue;

[0071] S7: Mix the solid residue with the activator to activate it and obtain porous carbon material.

[0072] Example 3

[0073] S1: Grind the kitchen waste to a particle size ≤5mm;

[0074] S2: Mix the chopped kitchen waste with water and perform heat treatment to separate the grease and slurry; mix the chopped kitchen waste with water at a solid-liquid ratio of 1:5 and perform heat treatment for 10 minutes at 40℃. After heat treatment, use a centrifuge at 3000 r / min for 5 minutes to separate the grease and slurry.

[0075] S3: Sugarcane bagasse is divided into bagasse A and bagasse B. Bagasse A is crushed to a particle size of 1 cm and then soaked in a 3% oxalic acid solution for 2.5 hours. After soaking, it is washed with water until neutral, dried, and then soaked in an ethanol solution for microwave treatment at 800W for 5 minutes to obtain modified bagasse. The modified bagasse is mixed with kitchen waste slurry at a mass ratio of 1:5 and then filtered to obtain the filtered slurry.

[0076] S4: The filtered slurry is mixed with 60% sugarcane bagasse B (with a particle size ≤5mm by weight), and then added to the fermentation device along with 0.5% potassium dihydrogen phosphate or magnesium sulfate by weight. 0.1% nano-catalyst material by weight is also added to the fermentation device for fermentation degradation. The fermentation device is stirred every 10 minutes, with a stirring speed of 100 rpm for 5 minutes, and the fermentation time is 6 hours.

[0077] S5: The fermented and degraded slurry is reheated and then subjected to secondary oil removal to obtain the oil-removed slurry.

[0078] S6: The oil-removed slurry is subjected to solid-liquid separation to obtain biomass carbon source liquid and solid residue;

[0079] S7: Mix the solid residue with the activator to activate it and obtain porous carbon material.

[0080] Comparative Example 1

[0081] In S2, the solid-liquid ratio of the chopped kitchen waste to water is 1:10, and all other conditions are the same as in Example 1.

[0082] Comparative Example 2

[0083] In S3, modified sugarcane bagasse and kitchen waste slurry were mixed and stirred at a mass ratio of 1:10, and then filtered to obtain filtered slurry. All other conditions were the same as in Example 1.

[0084] Comparative Example 3

[0085] S3 does not involve the modification of sugarcane bagasse A, and the steps of mixing and stirring the modified sugarcane bagasse with kitchen waste slurry at a mass ratio of 4:7 are the same as in Example 1.

[0086] Comparative Example 4

[0087] In S4, the filtered slurry was not mixed with bagasse B, and all other conditions were the same as in Example 1.

[0088] The biomass carbon source solutions obtained in Examples 1-3 and Comparative Examples 1-4 above were subjected to the following experiment:

[0089] The biomass carbon source solutions from Examples 1-3, Comparative Examples 1-4, and glucose carbon source solutions were sterilized at 120°C for 20 minutes. The sterilized carbon sources were used to prepare a basic fermentation medium with the same total sugar concentration. A specific amount of yeast was inoculated into the fermentation medium, and the medium was cultured with shaking at 30°C and 150 rpm. The glucose carbon source solution served as a blank control. Samples were aseptically collected after 48 hours of fermentation and analyzed as follows:

[0090] Cell biomass (DCW):

[0091] Take a certain volume of fermentation broth, centrifuge at 8000 rpm for 10 minutes, and discard the supernatant. Wash the precipitate twice with deionized water and centrifuge. Transfer the precipitate to a pre-weighed dry petri dish and dry it in a 105°C oven until constant weight. After cooling, weigh it and calculate DCW (g / L).

[0092] DCW (g / L) = (Weight after drying - Weight of container) / Sampling volume

[0093] Ethanol production by metabolism:

[0094] Take 1 mL of fermentation broth, centrifuge at 12000 rpm for 5 minutes to remove bacterial cells, and collect the supernatant. Perform quantitative analysis using gas chromatography (GC).

[0095] Yeast protein yield:

[0096] The protein content of the dried bacterial precipitate used for DCW determination was measured, and the results are shown in Table 1.

[0097] Table 1 Microbial fermentation test of biomass carbon source liquid

[0098]

[0099] In Examples 1-3, the DCW (dissolved carbon dioxide) ranged from 4.6 to 5.1 g / L, all higher than the blank control group, indicating that the biomass carbon source liquid from kitchen waste can efficiently support the growth and reproduction of yeast. The metabolic ethanol yield was between 20 and 22 g / L, and the yeast protein yield was between 2.3 and 2.5 g / L, both higher than the blank control group. This indicates that the obtained biomass carbon source liquid can simultaneously produce yeast protein and ethanol through fungal fermentation, unaffected by the acid-base conditions and high ammonia nitrogen in kitchen waste, and can be conveniently used for bio-fermentation, showing promise for large-scale application. In Comparative Examples 1-4, the DCW ranged from 1.5 to 3.8 g / L, generally lower. Comparative Example 3 (1.5 g / L), in particular, indicates that the presence of inhibitors in its carbon source severely hindered cell growth. The trends of metabolic ethanol and yeast protein yields were highly consistent with the DCW; poor cell growth inevitably leads to low yields of both.

[0100] The porous carbon materials obtained in Examples 1-3 and Comparative Examples 1-4 were subjected to the following experiment 2:

[0101] 100 mg of dried porous carbon materials from Examples 1-3, Comparative Examples 1-4, and commercially available activated carbon were weighed and placed into methylene blue solutions of known concentrations. The mixtures were shaken on a constant-temperature shaker until adsorption equilibrium was reached, then centrifuged and the supernatant was collected. The commercially available activated carbon served as a control group. The concentration of residual methylene blue in the solution was measured using a UV-Vis spectrophotometer, and Q was calculated. e

[0102]

[0103] Qe: equilibrium adsorption capacity (mg / g); CO: initial concentration of methylene blue (mg / L); C e m: Methylene blue concentration after adsorption equilibrium (mg / L); V: Solution volume (L); m: Mass of porous carbon material (g)

[0104] Table 2. Methylene Blue Adsorption Experiment of Porous Carbon Materials

[0105]

[0106] The test results are shown in Table 2. The adsorption performance of Examples 1-3 was better than that of the control group, indicating that the porous carbon material prepared by this invention has better adsorption performance than commercial activated carbon materials and has great application prospects. The data of Comparative Examples 1-4 were generally low (150-210 mg / g). The performance of Comparative Example 4 (150 mg / g) was the worst, which shows that there are serious problems in preparing porous carbon materials using only biomass carbon sources from kitchen waste, resulting in ineffective pore structures.

[0107] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a biomass carbon source based on food waste, characterized in that, The method comprises the following steps: S1: stirring the kitchen waste to a particle size of ≤5mm; S2: mixing the stirred kitchen waste with water, and separating the oil and slurry after heat treatment; S3: dividing the bagasse into bagasse A and bagasse B, stirring the bagasse A to a particle size of 1-1.5cm, then immersing it in an acid solution, and washing it with water to neutral, the acid solution is an oxalic acid solution with a mass concentration of 3-5%, then drying, immersing it in an ethanol solution, and performing microwave treatment to obtain modified bagasse, mixing the slurry with the modified bagasse, stirring, and filtering to obtain filtered slurry; S4: mixing the filtered slurry with bagasse B with a particle size of ≤5mm, and adding a microbial fermentation aid into a fermentation device to perform fermentation degradation; S5: heating the slurry after fermentation degradation again, and performing secondary oil removal to obtain slurry after oil removal; S6: performing solid-liquid separation on the slurry after oil removal to obtain a biomass carbon source liquid and solid residues; S7: mixing the solid residues with an activating agent to obtain a porous carbon material.

2. The method according to claim 1, wherein, The solid-liquid ratio of the stirred kitchen waste to water in step S2 is 1:(2-5).

3. The method according to claim 1, wherein the biomass carbon source is prepared from kitchen waste. The mass ratio of the bagasse A to the kitchen waste in step S3 is 2-4:7-10.

4. The method according to claim 3, wherein the biomass carbon source is prepared from kitchen waste. In step S3, the bagasse A is immersed in the oxalic acid solution for 2-3 hours, the microwave treatment power is 800-1000W, and the microwave treatment time is 5-10 minutes.

5. The method according to claim 1, wherein the biomass carbon source is prepared from kitchen waste. The heat treatment temperature in step S2 is 40-60℃, and the time is 10-60min.

6. The method according to claim 1, wherein the biomass carbon source is prepared from kitchen waste. In step S2, a centrifugal separation device is used to separate the oil and slurry, the centrifugal separation speed is 3000-5000r / min, and the time is 5-20min.

7. The method according to claim 1, wherein the biomass carbon source is prepared from kitchen waste. The microbial fermentation aid in step S4 is potassium dihydrogen phosphate or magnesium sulfate, and the microbial fermentation aid addition amount is 0.5%-1% of the slurry mass. 8.The method according to claim 2, characterized in that, In step S4, a nano catalytic material is also added into the fermentation device, and the nano catalytic material addition amount is 0.1%-0.3% of the slurry mass.

9. The method according to claim 8, wherein the biomass carbon source is prepared from kitchen waste. In step S4, the fermentation degradation time is 6-24h, the stirring is performed once every 10-120min, the stirring speed is controlled to 100-200r / min, and the stirring time is 5-10min. ​ 10. The method according to claim 7, wherein the biomass carbon source is prepared from kitchen waste. In step S4, the amount of the bagasse B is 60-80% of the filtered slurry mass.

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