Method for preparing furfural and co-producing activated carbon from oil tea fruit cattail

Abstract

The invention provides a method for preparing furfural and co-producing activated carbon from oil-tea camellia fruit cattail, which comprises the following steps: hydrolyzing hemicellulose in the oil-tea camellia fruit cattail by adopting Bronsted acid to directionally convert the hemicellulose into xylose, and further converting the xylose into furfural by utilizing Lewis acid; the influence of process parameters such as reaction temperature, reaction time, acid type, acid concentration and immobilization rate on the furfural yield is systematically investigated. And after the reaction is finished, filtering to obtain solid residues, and further preparing the camellia oleifera fruit and cattail activated carbon by adopting chemical activation and calcination methods. Adsorbing and purifying furfural by using the obtained activated carbon, and analyzing to obtain a furfural product. According to the method for preparing furfural and co-producing activated carbon from the oil-tea camellia fruit cattail, high-value conversion of hemicellulose in the oil-tea camellia fruit cattail and gradient utilization of solid residues are achieved, a closed-loop process path for full utilization and collaborative optimization of the oil-tea camellia fruit cattail is constructed, and the whole process is green and free of'three wastes' emission.

Description

Technical Field

[0001] This invention relates to the field of resource utilization technology of camellia oil processing waste, and in particular to a method for preparing furfural and co-producing activated carbon from camellia oil fruit. Background Technology

[0002] Lignocellulosic biomass, as an abundant renewable carbon resource, has enormous potential to replace fossil fuels. It is mainly composed of three components: cellulose (38%-50%), hemicellulose (23%-32%), and lignin (12%-25%), the contents of which vary significantly depending on the source of the raw material, plant species, and structural characteristics. Therefore, rationally selecting and controlling its utilization pathway based on the specific compositional characteristics of biomass is key to achieving efficient biomass refining. It is generally believed that enzymatic hydrolysis of cellulose to produce sugar and fermentation to produce bioethanol is more suitable for the biorefining of lignocellulosic biomass, which is predominantly cellulose.

[0003] Furfural, an important biomass platform compound, is mainly obtained from hemicellulose. Therefore, developing utilization pathways that preferentially convert hemicellulose into furfural is of great significance. Patent CN117186039A discloses a method for preparing furfural using acid catalysis and a two-phase reaction system consisting of an organic solvent, water, and an organic ammonium chloride salt, where xylose-based carbohydrates are dehydrated to obtain furfural. Patent CN116514746B discloses a method for preparing furfural from xylose-based carbohydrates in a ternary two-phase reaction medium consisting of a low-boiling-point organic solvent, a proton-type solvent, and an ionic organic ammonium chloride, under the action of a heteropolyacid phase transfer catalyst. Despite numerous methods for preparing furfural from hemicellulose, its large-scale production still faces several limitations. First, these processes struggle to achieve high solids content and have excessively long reaction times. Second, wastewater treatment during production presents challenges, leading to difficulties in furfural separation and environmental pollution. Third, furfural production is energy-intensive, requiring steam as both a heat source and an extractant; steam consumption is 30-50 times the furfural yield, resulting in high operating costs. Finally, the low purity of crude furfural increases the cost of subsequent purification steps. Developing a new technology for preparing furfural from hemicellulose as a raw material is of significant practical importance in addressing these common challenges.

[0004] Activated carbon is an amorphous carbon-based material renowned for its high specific surface area, porous structure, and abundant functional groups, making it widely used for adsorbing heavy metals, dyes, and other toxic substances. However, the high cost of commercially available activated carbon, primarily derived from non-renewable coal resources, limits its widespread application. Using abundant camellia and cattail resources to prepare activated carbon for furfural adsorption holds promise as a substitute for commercial activated carbon, reducing dependence on coal fossil fuels and achieving full utilization of these resources. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit, which realizes the high-value conversion of hemicellulose in Camellia oleifera fruit and the tiered utilization of solid residues, and constructs a closed-loop process path with full utilization of raw materials and synergistic optimization. The whole process is green and has no "three wastes" emissions.

[0006] To achieve the above objectives, the present invention provides a method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit, comprising the following steps: S1. Mix the camellia fruit and acid solution in a pressure-resistant glass flask with a solid loading rate of 5% (mass-volume ratio). Then, stir and heat the mixture of camellia fruit and acid solution. After the reaction is complete, filter to separate the filtrate containing xylose and the residue. S2. Add Lewis acid to the filtrate containing xylose, stir and mix, and heat to react to obtain crude furfural solution; S3. After drying the residue, grind and mix it thoroughly with the activator, and calcine it in two stages to obtain the initial activated carbon. The activated carbon is then acid-washed and water-washed in sequence until the filtrate reaches a neutral pH. Finally, it is dried and ground to obtain the activated carbon to be used. S4. Add the activated carbon to be used into the crude furfural solution for adsorption until adsorption equilibrium is reached. S5. Stir and mix the activated carbon after adsorbing furfural with the desorption solvent to desorb the furfural. Filter to obtain activated carbon with primary desorption. Perform secondary desorption on the activated carbon with primary desorption. After the desorption is completed, filter, recover the activated carbon, dry and regenerate it, and reuse it for subsequent furfural adsorption and desorption. Combine the solutions obtained from the two desorptions, evaporate and recover the desorption solvent to obtain the furfural product.

[0007] Preferably, the acid solution includes at least one of dilute hydrochloric acid, sulfuric acid, phosphoric acid, formic acid and acetic acid with a concentration of 1%-20%.

[0008] Preferably, the Lewis acid includes one or more of magnesium chloride, aluminum chloride, ferric chloride, chromium chloride, and lithium chloride; the Lewis acid concentration is 5-50 mg / mL, and the mass-to-volume ratio of Lewis acid to the filtrate containing xylose is (5~50):1.

[0009] Preferably, the activator includes one of zinc chloride, potassium hydroxide, and potassium bicarbonate, and the mass ratio of residue to activator is 1:(1~10).

[0010] Preferably, the mass-to-volume ratio of the activated carbon to the crude furfural solution is (1-20) 1:1.

[0011] Preferably, the desorbent includes one or more of ethanol, methanol, tetrahydrofuran, and 2-methyltetrahydrofuran, and the volume-to-mass ratio of the desorbent to the activated carbon after adsorbing furfural is (2~10):1.

[0012] Preferably, in S1, during stirring and heating, the reaction temperature is 100-150℃, the reaction time is 0.5-2h, and the stirring rate is 500 rpm.

[0013] Preferably, in S2, the reaction is carried out by heating at a temperature of 120℃-180℃ for a time of 0.5h-2h.

[0014] Preferably, in S3, the two-stage heating and calcination includes: the first stage calcination temperature is 400℃-600℃, and the calcination time is 0.5h-2h; the second stage calcination temperature is 800℃-1000℃, and the calcination time is 1h-4h.

[0015] Preferably, the time to reach adsorption equilibrium is 1-5 hours, and the temperature during adsorption is [temperature value missing]. In S5, the desorption temperature is 30-60℃, the desorption time is 1h-3h, and the temperature for evaporating and recovering the desorption solvent is 30-60℃.

[0016] Therefore, the present invention employs the above-mentioned method for preparing furfural-co-produced activated carbon from Camellia oleifera fruit, which not only achieves efficient conversion of hemicellulose to furfural by treating Camellia oleifera fruit, but also simultaneously obtains activated carbon material with good adsorption properties, demonstrating the characteristics of complete biomass utilization, green friendliness, and excellent overall economic efficiency. Firstly, under Brønsted acid conditions, hemicellulose in Camellia oleifera fruit is prone to hydrolysis due to its relatively amorphous molecular structure, high degree of branching, low degree of polymerization, and the presence of numerous easily protonated glycosidic bonds in its main chain. Therefore, under appropriate Brønsted acid concentrations and reaction temperatures, hemicellulose can be preferentially hydrolyzed into xylose, which is then further dehydrated using Lewis acid to generate furfural. Cellulose, on the other hand, exhibits high crystallinity and a regular molecular chain arrangement, making it more resistant to acidic conditions and less susceptible to significant degradation under these conditions. Meanwhile, lignin exhibits high structural stability in dilute acid systems, and its aromatic skeleton is not easily destroyed; during hydrolysis, it is primarily retained as a solid residue along with cellulose.

[0017] Secondly, after the reaction, the filtered solid residue was activated and carbonized to form activated carbon with a rich microporous structure and an aromatic carbon skeleton. During the carbonization and activation process, various oxygen-containing functional groups, including hydroxyl, carboxyl, and carbonyl groups, were introduced and retained on the surface of the activated carbon. These functional groups can form hydrogen bonds with the aldehyde group and furan epoxy atom in the furfural molecule. At the same time, the conjugated aromatic structure on the surface of the activated carbon can undergo π-π interactions with the furan ring of the furfural molecule, further enhancing its adsorption capacity for furfural.

[0018] Finally, through analysis, the furfural adsorbed on the activated carbon is released, the desorption agent is recovered, and high-purity furfural product is obtained. The overall process has advantages such as strong raw material adaptability, full utilization of components, and economic and environmental friendliness. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to the present invention; Figure 2 This represents the theoretical calculation amount of activated carbon adsorbing furfural. Figure 3 Langmuir model is used to show the isotherm curves for furfural adsorption by activated carbon. Figure 4 The Freundlich model is used to show the isotherm curves of furfural adsorption by activated carbon. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0022] A xylose solution is prepared by dilute acid hydrolysis of *Camellia oleifera* fruit. In a preferred embodiment, the immobilization rate of *Camellia oleifera* fruit in the dilute acid solution reaction system is 5%-50%. In the above preferred embodiment, the dilute acid solution includes one or more of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, with a concentration of 1%-20%. The reaction temperature is 100℃-150℃, and the reaction time is 0.5 h-2 h. Under the dilute acid and high temperature conditions, the hemicellulose in *Camellia oleifera* fruit mainly exists in the form of xylan, whose molecular structure is amorphous and contains a large number of β-1,4-glycosidic bonds in the main chain. Hydrogen ions in the dilute acid solution can protonate the oxygen atoms in the glycosidic bonds, thereby reducing the bond energy of the glycosidic bonds, which break with the participation of water molecules, causing the hemicellulose to gradually hydrolyze from the polymerized state into xylooligosaccharides and further generate xylose.

[0023] Xylose solution is dehydrated to furfural. In a preferred embodiment, the xylose solution is mixed with a Lewis acid solution. The Lewis acid can be one or more of magnesium chloride, aluminum chloride, ferric chloride, chromium chloride, and lithium chloride, at a concentration of 10-50 mg / mL. The reaction temperature is 120 ℃-180 ℃, and the reaction time is 0.5 h-2 h. The Lewis acid promotes the intramolecular rearrangement of xylose molecules to xylulose via 1,2-hydrogen transfer. Subsequently, under the action of Brønsted acid, the xylulose is dehydrated and converted to furfural.

[0024] Activated carbon is prepared from solid residue. In a preferred embodiment, the solid residue and activator are uniformly mixed at a mass ratio of 1:(1~10). The activator is selected from one or more of zinc chloride, potassium bicarbonate, potassium hydroxide, and sodium hydroxide. The calcination temperature is 400 ℃-800 ℃, and the calcination time is 1 h-5 h. The activator, through reaction with biomass at high temperatures, promotes the rearrangement and carbonization of the internal structure, forming abundant microporous and mesoporous structures, thereby significantly increasing the specific surface area and pore volume of the activated carbon. Furthermore, the activator can introduce or retain surface functional groups, such as hydroxyl, carboxyl, and carbonyl groups, during the carbonization process. These functional groups not only improve the surface chemical properties of the activated carbon but also enhance its adsorption capacity for target molecules. Therefore, the role of the activator is not only reflected in the optimization of the physical structure but also plays an important role in improving chemical activity and adsorption performance.

[0025] Activated carbon adsorbs furfural. In an optimized experimental scheme, the amount of activated carbon added was 5 mg–100 mg, the adsorption temperature was 20 ℃–60 ℃, and the adsorption time was 0.5 h–6 h. Due to the highly developed pore structure and large specific surface area of ​​activated carbon, furfural molecules can enter the micropores and mesopores of activated carbon through pore size matching and pore filling effects, thereby achieving effective capture. Secondly, at the chemical level, the surface of activated carbon has abundant oxygen-containing functional groups (such as hydroxyl, carboxyl, and carbonyl groups) and conjugated aromatic structures. These functional groups can form hydrogen bonds or π-π interactions with the aldehyde group and furan ring of furfural molecules, enhancing the stability of adsorption.

[0026] Eluent removal of furfural. In an optimized experimental scheme, one or more solvents, such as ethanol, methanol, tetrahydrofuran, and 2-methyltetrahydrofuran, are used to remove furfural adsorbed on activated carbon. The solvent is then recovered under reduced pressure to obtain the furfural product.

[0027] Example 1 A method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit includes the following steps: (1) Xylose solution was prepared by Brønsted acid hydrolysis of Camellia oleifera fruit; 2.5 g of Camellia oleifera fruit was mixed with 50 mL of 10% dilute hydrochloric acid (HA) solution in a 100 mL pressure-resistant glass flask, resulting in a solid content of 5%. The mixture was then heated to 130 °C and reacted with a stirring rate of 500 rpm for 1 h. After the reaction, the mixture was filtered, separating 50 mL of the xylose-containing filtrate from 1.6 g of residue. The xylose content in the filtrate was analyzed by high-performance liquid chromatography (HPLC) under the following conditions: Bio-Rad Aminex HPX-87P column, 5 mM sulfuric acid solution as the mobile phase, flow rate 0.6 mL / min, and column temperature 55 °C.

[0028] (2) Lewisacid and Brønstedacid synergistically promote the conversion of xylose to furfural; Add 0.75 g of magnesium chloride (15 mg / mL) to 50 mL of filtrate containing xylose, stir and mix, then introduce the resulting solution into a stainless steel reactor and react at 150 °C for 1.5 h to obtain 50 mL of crude furfural solution. Filter the supernatant through a 0.22 μm aqueous filter membrane, and analyze the furfural (FF) content by HPLC. Detection conditions: Bio-rad Aminex HPX-87H (300 × 7.8 mm) column (Biorad, USA), mobile phase: 5 mM sulfuric acid, flow rate: 1.0 mL / min, UV detector, detector temperature: 30 °C, detection wavelength: 276 nm.

[0029] ×100%; (3) Preparation of activated carbon from solid residue; After drying the residue from step (1) in an oven at 80°C, 1g of the residue was thoroughly ground and mixed with 4g of potassium hydroxide, placed in a porcelain boat, and then placed in a high-temperature tube furnace. The temperature was increased to 550°C at a rate of 10°C / min and calcined for 1 hour, then increased to 900°C and calcined for 2 hours. The resulting activated carbon was then acid-washed with 2mol / L hydrochloric acid solution for 24 hours, followed by washing with distilled water until the filtrate reached a neutral pH. Finally, it was dried and ground at 105°C and stored for later use.

[0030] (4) Activated carbon adsorbs furfural; Add 50 mg of activated carbon to 50 mL of furfural solution obtained in step (2), adsorb at 30 °C for 5 h. After adsorption equilibrium, take a sample for UV-vis absorbance colorimetric analysis of furfural adsorption amount, with a detection wavelength of 276 nm. The furfural adsorption amount is calculated according to the following formula: ; (5) Analysis of furfural 50 mg of activated carbon after adsorbing furfural in step (4) was placed in a 250 mL Erlenmeyer flask, and 50 mL of eluent was added. The mixture was stirred and stirred. The mixture was then kept at 30 °C for 1 h to eluent the furfural. The activated carbon was filtered and returned to the Erlenmeyer flask for a second eluent elution. After the eluent elution was completed, the activated carbon was filtered, recovered, dried, and regenerated for reuse in subsequent furfural adsorption and eluent elution. The solutions obtained from the two eluent elutions were combined and placed in a 60 °C rotary evaporator to recover the eluent elution solvent, yielding the furfural product. The recovered eluent elution solvent can be reused. The experimental results are shown in Table 1 and [Table data missing]. Figure 1 .

[0031] Table 1 Hemicellulose removal rate, xylose concentration, and furfural yield

[0032] Comparative Example 2 The 50 mL 10% dilute hydrochloric acid (HA) solution in Example 1 was replaced with the same amount of 10% sulfuric acid solution, phosphoric acid, formic acid and acetic acid. Everything else was the same as in Example 1. The effects of the types of Lewis acids on the hydrolysis of Camellia oleifera fruit to prepare xylose were analyzed. The experimental results are shown in Table 2.

[0033] Table 2. Effects of different types of dilute acids on hemicellulose removal rate, xylose concentration, and furfural yield.

[0034] Comparative Example 3 The 10% sulfuric acid solution in Example 2 was replaced with sulfuric acid solutions of concentrations of 1%, 5%, 15%, and 20% to analyze the effect of Lewis acid concentration on the preparation of xylose from hydrolyzed Camellia oleifera fruit. Other aspects were the same as in Example 2. The experimental results are shown in Table 3.

[0035] Table 3. Effects of dilute acid concentration on hemicellulose removal rate, xylose concentration, and furfural yield.

[0036] Comparative Example 4 The heating temperatures of Camellia oleifera fruit and 10% sulfuric acid solution were modified to 100℃, 120℃, 140℃, and 150℃, while other conditions remained the same as in Example 2. The effect of heating temperature of Camellia oleifera fruit and 10% sulfuric acid solution on the preparation of xylose from the hydrolysis of Camellia oleifera fruit was analyzed. The experimental results are shown in Table 4.

[0037] Table 4. Effects of reaction temperature on hemicellulose removal rate, xylose concentration, and furfural yield

[0038] Comparative Example 5 The effects of varying solid content (10%, 20%, and 30%) on the preparation of xylose from hydrolyzed Camellia oleifera fruit were investigated. Other aspects were the same as in Example 2. The effects of solid content on the preparation of xylose from hydrolyzed Camellia oleifera fruit were analyzed, and the experimental results are shown in Table 5.

[0039] Table 5. Effects of solid content on hemicellulose removal rate, xylose concentration, and furfural yield.

[0040] Comparative Example 6 The heating time of Camellia oleifera fruit and 10% sulfuric acid solution was changed to 0.5h, 1.5h, and 2h, respectively, while other conditions remained the same as in Example 2. The effect of heating time of Camellia oleifera fruit and 10% sulfuric acid solution on the preparation of xylose from the hydrolysis of Camellia oleifera fruit was analyzed. The experimental results are shown in Table 6.

[0041] Table 6. Effects of reaction time on hemicellulose removal rate, xylose concentration, and furfural yield.

[0042] Comparative Example 7 In Example 1, magnesium chloride was replaced with aluminum chloride, chromium chloride, lithium chloride, and ferric chloride. The effects of different Lewis acids on the conversion of xylose to furfural were analyzed. Other aspects were the same as in Example 1. The experimental results are shown in Table 7.

[0043] Table 7. Effect of Lewis acid type on furfural yield

[0044] Comparative Example 8 The concentration of magnesium chloride in Example 1 was modified to 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, and 50 mg / mL, while other parameters remained the same as in Example 1. The effect of Lewis acid concentration on the conversion of xylose to furfural was analyzed, and the experimental results are shown in Table 8.

[0045] Table 8. Effect of Lewis acid concentration on furfural yield

[0046] Comparative Example 9 The reaction temperatures for obtaining crude furfural were modified to 120℃, 140℃, and 160℃, while other conditions remained the same as in Example 1. The effect of the reaction temperature on the conversion of xylose to furfural was analyzed, and the experimental results are shown in Table 9.

[0047] Table 9. Effect of reaction temperature on furfural yield during xylose-to-furfural conversion (a)

[0048] a: The reaction temperature at which Lewis acid and Brønsted acid synergistically promote the conversion of xylose to furfural.

[0049] Comparative Example 10 The reaction time for obtaining crude furfural was modified to 0.5 h, 1 h, and 2 h, while other steps remained the same as in Example 1. The reaction time for xylose to convert to furfural and the effect of xylose on furfural conversion were analyzed. The experimental results are shown in Table 10.

[0050] Table 10 Effect of reaction time on furfural yield during xylose-to-furfural conversion.

[0051] a: The reaction temperature at which Lewis acid and Brønsted acid synergistically promote the conversion of xylose to furfural.

[0052] Comparative Example 11 In Example 1, the activator potassium hydroxide was replaced with zinc chloride and potassium bicarbonate, while other aspects remained the same as in Example 1. The effect of the type of activator on the performance of activated carbon was analyzed, and the experimental results are shown in Table 11.

[0053] Table 11 Adsorption of furfural by activated carbon

[0054] Comparative Example 12 The solvent used in Example 1 was replaced with ethanol, methanol, tetrahydrofuran, or 2-methyltetrahydrofuran, while all other aspects remained the same as in Example 1. The effect of the type of solvent on the recovery rate of furfural was analyzed, and the experimental results are shown in Table 12. Figure 2 , Figure 3 , Figure 4 .

[0055] Table 12. Effect of solvent type on furfural desorption efficiency

[0056] Therefore, the present invention adopts the above-mentioned method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit and cattail, realizing the high-value conversion of hemicellulose in Camellia oleifera fruit and cattail, as well as the cascade utilization of solid residue, and constructing a closed-loop process path for the full utilization and synergistic optimization of Camellia oleifera fruit and cattail. The whole process is green and has no "three wastes" emissions.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit, characterized in that, Includes the following steps: S1. Mix the camellia fruit and acid solution in a pressure-resistant glass flask. The mass-volume ratio of the camellia fruit and acid solution is 5%-50%. Then, stir and heat the mixture of camellia fruit and acid solution. After the reaction is completed, filter to separate the filtrate containing xylose and the residue. S2. Add Lewis acid to the filtrate containing xylose, stir and mix, and heat to react to obtain crude furfural solution; S3. After drying the residue, grind and mix it thoroughly with the activator, and calcine it in two stages to obtain the initial activated carbon. The activated carbon is then acid-washed and water-washed in sequence until the filtrate reaches a neutral pH. Finally, it is dried and ground to obtain the activated carbon to be used. S4. Add the activated carbon to be used into the crude furfural solution for adsorption until adsorption equilibrium is reached. S5. Stir and mix the activated carbon after adsorbing furfural with the desorption solvent to desorb the furfural. Filter to obtain activated carbon with primary desorption. Perform secondary desorption on the activated carbon with primary desorption. After the desorption is completed, filter, recover the activated carbon, dry and regenerate it, and reuse it for subsequent furfural adsorption and desorption. Combine the solutions obtained from the two desorptions, evaporate and recover the desorption solvent to obtain the furfural product.

2. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, The acid solution includes at least one of the following: dilute hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid, with a concentration of 1%-20%.

3. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, Lewis acids include one or more of magnesium chloride, aluminum chloride, ferric chloride, chromium chloride, and lithium chloride; the concentration of Lewis acid is 5-50 mg / mL, and the mass-to-volume ratio of Lewis acid to filtrate containing xylose is (5~50):

1.

4. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, The activator includes one of zinc chloride, potassium hydroxide, and potassium bicarbonate, and the mass ratio of residue to activator is 1:(1~10).

5. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, The mass-to-volume ratio of the activated carbon to the crude furfural solution is (1-20) 1:

1.

6. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, The desorbent includes any one or more of ethanol, methanol, tetrahydrofuran, and 2-methyltetrahydrofuran, and the ratio of the desorbent to the activated carbon after adsorbing furfural is (2~10):

1.

7. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, In S1, during stirring and heating, the reaction temperature is 100-150℃, the reaction time is 0.5-2h, and the stirring rate is 500 rpm.

8. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, In S2, the reaction is carried out under heat at a temperature of 120℃-180℃ for a time of 0.5h-2h.

9. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, In S3, the two-stage calcination process includes: the first stage calcination temperature is 400℃-600℃, and the calcination time is 0.5h-2h; the second stage calcination temperature is 800℃-1000℃, and the calcination time is 1h-4h.

10. The method for preparing furfural and co-producing activated carbon from Camellia oleifera fruit according to claim 1, characterized in that, The time to reach adsorption equilibrium is 1-5 hours, and the temperature during adsorption is: In S5, the desorption temperature is 30-60℃, the desorption time is 1h-3h, and the temperature for evaporating and recovering the desorption solvent is 30-60℃.

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