Amorphous Graphene Manufacturing Method And Material Comprising the Amorphous Graphene Made thereby

Abstract

The present invention relates to a method for manufacturing amorphous graphene using woody carbon with excellent environmental friendliness and a product comprising graphene manufactured thereby. More specifically, the invention relates to a method for manufacturing amorphous graphene that can produce amorphous graphene having antibacterial, electrostatic, deodorizing, and conductive functions in a more environmentally friendly manner, and a product comprising graphene manufactured thereby. The present invention comprises: a raw material preparation step (S1) for preparing lignocellulosic carbon; an oxidation solution preparation step (S2) for making an oxidation solution by dissolving ammonium persulfate ((NH4)2S2O8) in distilled water; a graphene oxidation solution manufacturing step (S3) for forming graphene oxide by mixing lignocellulosic carbon and the oxidation solution; a graphene dispersion step (S4) for making a mixed solution by adding a dispersion solution containing spherical nanocellulose crystals having hydrophobic properties and ethanol to the graphene oxidation solution and mixing them; and a heat treatment step (S5) for maintaining the mixed solution at a high temperature for a predetermined time and cooling it after the graphene dispersion step (S4).

Description

Technology Field

[0001] With the recent implementation of regulatory measures regarding the manufacture of living environment products using mineral-based graphene, the present invention proposes a method for manufacturing graphene with excellent environmental friendliness. Specifically, the present invention relates to a method for manufacturing amorphous graphene using woody carbon with excellent environmental friendliness and a product containing graphene manufactured thereby. More specifically, the invention relates to a method for manufacturing amorphous graphene that can produce amorphous graphene having antibacterial, electrostatic, deodorizing, and conductive functions in a more environmentally friendly manner, and a product containing graphene manufactured thereby. Background Technology

[0002] Graphene is a two-dimensional material with a single-layer structure composed of carbon atoms, arranged in a honeycomb-shaped hexagonal lattice, and has a very thin film structure with a thickness of only a single atom. Graphene possesses the following characteristics, which have led to significant research and potential applications.

[0003] ○ Strength: Graphene is known to be about 100 times stronger than steel and is one of the strongest materials currently in existence.

[0004] ○ Electrical Conductivity: Graphene possesses excellent electrical conductivity, characterized by very fast electron mobility. This makes it applicable to next-generation electronic devices, batteries, and ultra-high-speed transistors.

[0005] ○ Thermal conductivity: Graphene has high thermal conductivity, which allows it to efficiently dissipate heat.

[0006] ○ Transparency: Graphene is nearly transparent, allowing more than 97.7% of light to pass through. This property can be useful as a material for transparent electronic devices or displays.

[0007] ○ Flexibility: Graphene is very thin and flexible, so it has the advantage of being able to be deformed into various shapes.

[0008] Thanks to these properties of graphene, innovative applications are expected in various fields, such as electronic devices, energy storage devices, composite materials, and biosensors.

[0009] However, such graphene is mass-produced using liquid exfoliation methods, such as oxidizing graphite powder with sulfuric acid and exfoliating it in an aqueous solution using ultrasound, heat, etc.

[0010] The prior art, Registered Patent No. 10-1380940 (hereinafter referred to as the prior art), relates to a method for manufacturing graphene oxide for mass production, and more specifically, to a method for manufacturing graphene oxide for mass production in which high-quality graphene oxide can be obtained through acid treatment using an optimal ratio of sulfuric acid, nitric acid, and potassium chlorate, followed by drying, expansion, and exfoliation processes.

[0011] However, since these conventional technologies use sulfuric acid, etc., they remain as highly toxic acids, so alkali must be added to reduce them, and in that case, salts (sulfates) are generated and pollutants are emitted.

[0012] The applicant and inventor of the present invention developed a method for producing large-area graphene by adding graphite to a dispersion containing hydrogen peroxide and registered it as Patent No. 10-2597242 (registration date 2023.10.30).

[0013] With the recent implementation of regulatory measures regarding the manufacturing of living environment products using mineral-based graphene, there is a new demand for methods to manufacture graphene with excellent environmental friendliness.

[0014] Furthermore, unlike crystalline graphene, in which carbon atoms are regularly arranged in a hexagonal honeycomb structure, amorphous graphene consists of irregularly arranged carbon atoms, where the traditional hexagonal honeycomb structure exists only partially or is broken. Due to the irregular atomic arrangement and defects, amorphous graphene exhibits lower electrical and thermal conductivity compared to crystalline graphene, and its mechanical strength and flexibility are also weaker; however, in certain applications, these lower mechanical strengths and flexibility can be advantageous. Additionally, amorphous graphene possesses high chemical reactivity due to its large surface area and structural instability; these characteristics can be particularly beneficial in application fields such as catalysts, sensors, and energy storage devices.

[0015] There is increasing demand from the industry for methods to manufacture amorphous graphene with these characteristics using environmentally friendly processes. The problem to be solved

[0016] The present invention was devised to solve the above problems and aims to provide a graphene manufacturing method capable of producing amorphous graphene through an environmentally friendly process in which the emission of toxic substances during the manufacturing process is suppressed, and a product comprising graphene produced by this method.

[0017] Furthermore, the present invention aims to provide a method for manufacturing woody amorphous graphene that allows for easier production and post-processing, and a product comprising graphene manufactured thereby. means of solving the problem

[0018] The present invention, aimed at solving the above problem, has the following structure and features.

[0019] The method includes a raw material preparation step (S1) for preparing woody carbon; an oxidation solution preparation step (S2) for making an oxidation solution by dissolving ammonium persulfate ((NH4)2S2O8) in distilled water; a graphene oxidation solution manufacturing step (S3) for forming graphene oxide by mixing woody carbon and the oxidation solution; a graphene dispersion step (S4) for making a mixed solution by adding a dispersion solution containing spherical nanocellulose crystals having hydrophobic properties and ethanol to the graphene oxidation solution and mixing them; and a heat treatment step (S5) for maintaining the mixed solution at a high temperature for a predetermined time and cooling it after the graphene dispersion step (S4).

[0020] In addition, the oxidation solution is characterized by containing ammonium persulfate ((NH4)2S2O8) at a molarity of 0.3 to 0.5 molarity, and by preparing a graphene oxidation solution with a ratio of 1:2 between woody carbon and an oxidizing agent (ammonium persulfate).

[0021] In addition, the heat treatment step (S5) is characterized by promoting the formation of amorphous graphene by performing high-temperature heat treatment at a temperature between 200 and 400°C for 1 to 2 hours in an oxygen-free atmosphere, and then rapidly cooling to a temperature of 0°C or lower.

[0022] In addition, the present invention is characterized in that, in a product comprising graphene produced by a method for producing amorphous graphene, the graphene solution is applied to at least a portion of the outer surface of the product.

[0023] Another problem to be solved by the present invention and specific means for solving it will be explained in more detail in the 'specific details for implementing the invention' and the attached drawings described below. Effects of the invention

[0024] The present invention, having the above composition and features, can suppress the emission of toxic substances by preparing an oxidation solution by mixing ammonium persulfate ((NH4)2S2O8) with distilled water, as sulfuric acid is not used. In addition, by using lignocellulosic carbon, it is an environmentally friendly and sustainable raw material that is cheaper than graphite, and since it does not generate salt during the graphene manufacturing process, it has the effect of being able to manufacture amorphous graphene with antibacterial functions in an environmentally friendly manner.

[0025] Furthermore, by omitting the reduction process (no reducing agent added) during the step of forming graphene oxide, the graphene oxide can be maintained in its defect-rich structure, thereby better preserving the amorphous properties of the graphene oxide. Additionally, by omitting the reduction process, the process is simplified, manufacturing costs and time can be saved, and graphene can be manufactured using a more environmentally friendly process since no additional chemicals (reducing agents) are used.

[0026] In addition, the present invention has the effect of inhibiting the reversion of exfoliated graphene into graphite by including spherical nanocellulose crystals in the functional ingredient.

[0027] Another functional effect of the present invention will be explained in more detail in the 'Specific details for implementing the invention' described below. Brief explanation of the drawing

[0028] FIG. 1 is a schematic block diagram illustrating a method for manufacturing large-area graphene according to one embodiment of the present invention. Figure 2 is a graph analyzing the structural characteristics of amorphous graphene produced by the method of the present invention using Raman spectroscopy. FIG. 3 is a drawing for explaining a product containing graphene manufactured by a large-area graphene manufacturing method according to one embodiment of the present invention. Figure 4 is a particle size property analysis table of amorphous graphene manufactured according to the present invention. Figure 5 is an analysis table showing the measured zeta potential of amorphous graphene prepared according to the present invention. Specific details for implementing the invention

[0029] The present invention is capable of various modifications and may take various forms, and embodiments (aspects or examples) are to be described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0030] The terms used in this specification are used merely to describe specific embodiments (aspects or examples) and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “consisting of” are intended to indicate the presence of the features, numbers, steps, actions, components, compositions, components, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0031] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0032] The terms "~1~," "~2~," etc., described in this specification are used merely to distinguish different components and are not bound by the order of manufacture; furthermore, the names may not match those in the detailed description of the invention and the claims.

[0033] Throughout the entire specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other components in between.

[0034] FIG. 1 is a schematic block diagram illustrating a method for manufacturing graphene according to one embodiment of the present invention.

[0035] A graphene manufacturing method according to one embodiment of the present invention relates to a method for manufacturing graphene in an environmentally friendly manner, and for convenience of explanation, it will be referred to as "the present method" below.

[0036] Referring to FIG. 1, the present method (a method for manufacturing amorphous graphene according to a preferred embodiment of the present invention) comprises a raw material preparation step (S1) for preparing woody carbon, an oxidation solution preparation step (S2) for making an oxidation solution, a graphene oxide solution preparation step (S3) for mixing woody carbon and the oxidation solution to form graphene oxide, a graphene dispersion step (S4) for introducing a dispersion solution into the graphene oxide solution and mixing to make a mixed solution, and a heat treatment step (S5) for maintaining the mixed solution at a high temperature for a predetermined time and cooling it.

[0037] 1. Raw material preparation step for preparing woody carbon (S1)

[0038] The above raw material preparation step (S1) is a step of preparing woody carbon.

[0039] Lignocellulosic carbon is characterized as a raw material for graphene that is cheaper and more sustainable than graphite. The step of preparing lignocellulosic carbon is a critical one that affects the quality of amorphous graphene.

[0040] Woody carbon is a biomass-based material, and high-quality graphene can be obtained through appropriate pretreatment and carbonization processes. The process for obtaining woody carbon according to the present invention is as follows.

[0041] 1-1. Selection of Raw Materials

[0042] Various biomass materials, such as wood, bamboo, and coconut shells, can be used to obtain woody carbon, but it is important to select materials with high carbon content and low impurity content.

[0043] 1-2. Preprocessing

[0044] The pretreatment step is a process of drying and grinding the raw materials. Since moisture can cause incomplete combustion during the carbonization process, the raw materials are sufficiently dried to remove moisture. Additionally, grinding the raw materials into fine particles increases the surface area and promotes uniform carbonization.

[0045] 1-3. Pyrolysis

[0046] Generally, the temperature is maintained at 400 to 800°C for about 1 to 3 hours to ensure sufficient carbonization. During this process, organic components of the raw material are removed, and a carbon structure is formed. In particular, by performing carbonization in an oxygen-free environment (e.g., an argon or nitrogen atmosphere), oxidation can be prevented and a pure carbon structure can be maintained.

[0047] 1-4. Activation Phase

[0048] Carbon is activated by heating at 700 to 1,000°C using CO2 or steam. In the activation step, CO2 or steam reacts with the carbon surface to form a microstructure.

[0049] 1-5. Washing and Drying

[0050] After activation, the woody carbon is cooled and washed to remove impurities, and then finally dried to obtain pure woody carbon.

[0051] 2. Oxidation solution preparation step (S2)

[0052] Conventionally, liquid exfoliation methods were used to produce graphene by chemically exfoliating such graphite powder through oxidation using sulfuric acid (in which case ultrasound or heat may be additionally used).

[0053] Large-area graphene was formed on the surface of a target object (e.g., a mask) by applying and drying an aqueous graphene solution prepared by such conventional liquid exfoliation methods, utilizing the self-assembly principle in which molecules or atoms assemble and rearrange themselves without assistance.

[0054] However, when sulfuric acid is used as an oxidizing agent as in the aforementioned conventional technology, residual sulfuric acid remains in the graphene aqueous solution, raising concerns regarding its harmfulness to the human body. Furthermore, when alkali is added to offset these issues, salts (sulfates) are generated, producing pollutants that act as a cause of environmental destruction.

[0055] The present method is characterized by using a peroxide as an oxidizing agent to replace sulfuric acid, which is a problem of conventional technology. The oxidation solution preparation step (S2) according to the present invention involves dissolving ammonium persulfate ((NH4)2S2O8) in distilled water to prepare an oxidation solution. In the oxidation solution, the concentration of ammonium persulfate is preferably 0.3 to 0.5 molarity. That is, the ratio of distilled water to ammonium persulfate in the oxidation solution is appropriately 90 to 6 to 10. If the concentration is too low (less than 0.3 M), the oxidizing power required for the formation of graphene oxide becomes insufficient, resulting in incomplete formation of graphene oxide, making it difficult to obtain desired properties, and the oxidation reaction proceeds slowly, increasing the overall process time. Conversely, if the concentration is too high (more than 0.5 M), the structure of graphene may be excessively oxidized and damaged, which may lead to a deterioration in the electrical and mechanical properties of graphene. In addition, high concentrations of oxidizing agents can reduce the safety of the reaction and can be dangerous due to exothermic reactions, especially when reacting at high temperatures.

[0056] 3. Graphene oxide preparation step (S3)

[0057] The step involves mixing woody carbon into the oxidation solution to form graphene oxide. In this step, the optimal ratio of woody carbon to the oxidizing agent (ammonium persulfate) is most preferably 1:2.

[0058] For example, when using 10 g of lignocellulosic carbon as a reference, if the oxidation solution has a concentration of 0.4 molar, the molar mass of ammonium persulfate is approximately 228.2 g / mol, so 219 ml of the oxidation solution becomes the titration volume to contain 20 g of ammonium persulfate. If the oxidation solution has a concentration of 0.3 molar, the titration volume is 292 ml, and if the oxidation solution has a concentration of 0.5 molar, the titration volume is 175.3 ml.

[0059] The manufacturing method according to the present invention is characterized by maintaining amorphous properties by omitting the reduction process of graphene oxide contained in the graphene oxide solution. That is, by omitting the reduction process without adding a reducing agent in the graphene oxide solution manufacturing step (S3), the graphene oxide can be maintained in its defect-rich structure, thereby better preserving the amorphous properties of the graphene oxide. Furthermore, by omitting the reduction process, the process is simplified, manufacturing costs and time can be saved, and graphene can be manufactured using a more environmentally friendly process since no additional chemical substances (reducing agents) are used.

[0060] 4. Graphene dispersion step (S4)

[0061] In the graphene dispersion step (S4), a dispersion solution is added to and mixed with a graphene oxide solution in which graphene oxide has been formed to create a mixed solution. The dispersion solution according to the present invention comprises, when the total weight of the dispersion solution is 100, 0.5 to 1.0 weight% of hydrophobic spherical nanocellulose crystals and sodium dodecyl sulfate (CH3(CH2) 10 It is characterized by being prepared by mixing 0.2 to 0.5 wt% of CH2OSO3Na), 75 to 85 wt% of ethanol, and 14 to 20 wt% of distilled water.

[0062] The spherical nanocellulose crystals (0.5 to 1.0 wt%) having the above hydrophobic properties maintain the spacing between graphene sheets and prevent the recombination of graphene, thereby helping to achieve uniform dispersion. In particular, the hydrophobic properties can enhance physical stability by strengthening the interaction with graphene.

[0063] In addition, sodium dodecyl sulfate (SDS, 0.2 to 0.5 wt%) acts as a surfactant to reduce the surface tension of graphene sheets and promote dispersion. In particular, it can prevent the aggregation of graphene and maintain stable dispersion in solution.

[0064] Furthermore, ethanol is a molecule that possesses both polar and non-polar parts. Specifically, the hydroxyl group (-OH) of ethanol (C2H5OH) acts as the polar part, allowing it to mix well with polar solvents such as water; conversely, the hydrocarbon tail (C2H5-) acts as the non-polar part, enabling it to interact with non-polar substances. Due to this duality, ethanol serves as a good solvent capable of dissolving both polar and non-polar materials. Possessing these characteristics, ethanol can control polarity as a solvent and regulate the interactions between graphene and other components. In particular, ethanol improves the dispersibility of graphene and facilitates processing by controlling the viscosity of the solution.

[0065] Distilled water (14 to 20 wt%) acts as a solvent to balance the overall dispersion and control interactions with other components. In particular, distilled water can be mixed with ethanol to control the viscosity and stability of the solution.

[0066] A dispersion containing such a composition effectively enhances the uniform dispersion and stability of graphene. In particular, the combination of hydrophobic nanocellulose and SDS prevents aggregation between graphene sheets, and the ratio of ethanol to water controls the viscosity and solubility of the solution, thereby supporting the uniform dispersion of graphene.

[0067] In the graphene dispersion step (S4), the ratio of the dispersion solution added to the graphene oxide solution is preferably 8 to 12 weight percent of the total weight of the graphene oxide solution.

[0068] When adding a dispersion solution to a graphene oxide solution, various problems can arise if the amount added is excessive or insufficient. If an excessive amount of dispersion solution is added, the graphene concentration becomes too low, making it difficult to obtain amorphous graphene with desired properties. Additionally, the distance between graphene sheets may become too large, reducing their interactions. Furthermore, if excessive surfactants or stabilizers are included, the graphene sheets may separate excessively, causing problems when aggregation is required. Moreover, using an unnecessarily large amount of dispersion solution increases material costs and reduces the economic viability of the process. Conversely, if the dispersion solution is insufficient, the graphene sheets may not disperse properly, leading to the formation of aggregation or clumps. This can reduce the specific surface area of ​​the graphene and degrade its electrical or physical properties. Additionally, insufficient dispersion can cause graphene sheets to recombine to form large particles, negatively impacting the quality of the final product. Finally, insufficient stabilization can lead to a decrease in the stability of the graphene solution over time and the formation of precipitates.

[0069] As such, the amount of dispersion added is very important for maintaining the quality and characteristics of graphene. In the present invention, uniform dispersion and stability of graphene can be secured by adding the dispersion in the range of 8 to 12 weight percent of the total weight of the graphene oxide solution.

[0070] 5. Heat treatment step (S5)

[0071] The heat treatment step (S5) is a step of maintaining the mixed solution at a high temperature for a predetermined time and cooling it after the graphene dispersion step (S4). If the heat treatment step (S5) is performed in an oxygen-free environment (e.g., an argon or nitrogen atmosphere), it not only helps prevent oxidation of the graphene but also allows for the maintenance of a pure carbon structure and the maintenance of the electrical properties of the graphene.

[0072] In addition, the temperature of the heat treatment step is appropriately between 200 and 400°C, as this temperature range can evaporate residual peroxides and partially reduce graphene oxides to promote the formation of an amorphous structure. It is preferable to perform high-temperature heat treatment for about 1 to 2 hours to provide sufficient time for the complete removal of peroxides and structural changes.

[0073] Here, a high-temperature heat treatment method of 700°C or higher can be considered because heat treatment at a high temperature of 700°C or higher can accelerate chemical reactions to promote the reduction of graphene oxide and the removal of impurities, and can help form an amorphous structure through rapid cooling from high temperatures. However, since temperatures of 700°C or higher are likely to cause crystallization of graphene, they can have adverse effects contrary to the purpose of the present invention of maintaining amorphous properties, and can also cause thermal damage to the material, thereby negatively affecting the physical properties of graphene. Therefore, a heat treatment temperature between 200 and 400°C is appropriate in the method for manufacturing amorphous graphene according to the present invention.

[0074] In addition, rapid cooling is particularly advantageous for forming an amorphous structure. That is, since rapid cooling immediately after high-temperature heat treatment fixes the atomic arrangement in an irregular state, it can promote the formation of amorphous graphene. This helps maintain amorphous properties by preventing the graphene from forming a crystal structure. For this reason, it is preferable that the cooling in the heat treatment step of the present invention be carried out at a temperature of 0°C or lower, more preferably in a nitrogen gas atmosphere of -50 to -100°C.

[0075] The heat treatment step (S5) has the advantage of effectively suppressing the graphene from returning to graphite in the graphene solution while evaporating residual peroxide in the graphene solution.

[0076] Generally, the yield of graphene manufacturing methods varies depending on process conditions, the concentration of chemicals used, reaction time, etc., but the method for manufacturing amorphous graphene according to the present invention can secure a yield of about 35 to 50%. That is, since about 3.5 to 5 g of amorphous graphene can be obtained from 10 g of woody carbon, the present invention is a very excellent method for manufacturing graphene in that it can secure a high yield.

[0077] In addition, as a result of analyzing the structural characteristics of the amorphous graphene prepared by the method of the present invention using Raman spectroscopy, the ID / IG ratio was confirmed to be 1.58, as shown in Fig. 2. For reference, the ID / IG ratio is the D-band, which indicates defects or irregular structures, and sp 2 It is the ratio of the relative intensity of G-bands representing carbon-carbon bond vibrations, and is used as a criterion for evaluating the degree of defects and amorphousness. In the case of crystalline graphene, the ID / IG ratio generally appears as a low value of 0.1 or less, which indicates low defects and high crystallinity. Conversely, the ID / IG ratio of amorphous graphene generally shows a value between 1 and 3, although the ID / IG ratio may be higher than this depending on process conditions.

[0078] The amorphous graphene produced by the present invention can be manufactured into various products by a compounding process (a process of creating a new composite material by mixing two or more materials). For example, synthetic fiber yarns such as nylon, polyester, and polypropylene can be manufactured by mixing the amorphous graphene produced by the present invention with raw materials.

[0079] As another embodiment, the amorphous graphene according to the present invention may be applied to the surface of the object to form a large-area graphene coating layer due to its self-assembly properties. When manufacturing a product by such graphene coating, the present method may further include a coating and drying step (S6). The coating and drying step (S6) is a step of applying and drying the graphene solution after the heat treatment step (S5) to the surface of the product. FIG. 3 is a drawing for explaining a product containing graphene manufactured by the method for manufacturing amorphous graphene according to one embodiment of the present invention, showing the application and drying of the graphene solution after the heat treatment step (S5) to the surface of a mask. A method for coating a large area of ​​amorphous graphene manufactured by the present invention onto the surface of a mask is briefly described. A large area of ​​amorphous graphene according to the present invention can be coated by evenly spraying a dispersion containing amorphous graphene that has undergone the heat treatment step (S5) onto the surface of a mask using an airbrush or a spray device. At this time, it is important to thoroughly mix the dispersion containing amorphous graphene before spraying to maintain a uniform concentration, and it is also important to clean the mask thoroughly and dry it completely. Additionally, when spraying the graphene dispersion, it is necessary to adjust the spray pressure and spray distance to ensure a uniform coating, and by spraying repeatedly in thin layers, a uniform coating that is not thick can be achieved.

[0080] In addition to the spray coating method, it is possible to coat a large area of ​​the product surface with graphene using a dip coating method. For example, this method involves immersing a mask (or product) in a graphene dispersion and then slowly removing it to form a uniform coating on the surface. After coating, the excess solvent must be removed by air drying or drying at a low temperature. Subsequently, the coated mask (or product) is dried at room temperature to stabilize the amorphous graphene coating layer. By maintaining a sufficient stabilization time after coating, the graphene layer adheres well to the mask surface.

[0081] In addition, a product containing graphene manufactured according to the present invention may be, for example, a mask, but is not limited thereto. The object may be formed of a material made of various materials, such as fibers or polymers, that can be manufactured by a compounding process. The object may also be diverse as long as the graphene solution is applied. As the graphene solution is applied to the object and dried, the exfoliated graphene can form large-area graphene on the surface of the object through self-assembly.

[0082] Figure 4 is a particle size property analysis table of amorphous graphene prepared according to the present invention. As shown in Figure 4, it can be seen that the intensity distribution of the amorphous graphene according to the present invention is highest at a particle size of 0.3 nm, the volume distribution is highest at a particle size of 0.2 nm, and the particle number distribution is highest at a particle size of 0.1 nm.

[0083] Figure 5 is an analysis table showing the measured zeta potential of amorphous graphene prepared according to the present invention. The zeta potential of amorphous graphene is an important indicator for evaluating the stability of graphene particles in a liquid medium. Zeta potential represents the interaction between the charge on the particle surface and ions in the liquid, and is used to predict the dispersion stability and aggregation tendency of the particles. The zeta potential measured in the amorphous graphene prepared according to the present invention is +70 mV or higher, confirming that the electrostatic repulsion between particles is very strong, allowing the particles to maintain a stable dispersed state without aggregating with each other. If the zeta potential is low (±30 mV or less), the repulsion between particles weakens, causing the particles to easily aggregate; this is an important indicator, especially for nanoparticles such as amorphous graphene.

[0084] This method can suppress the emission of toxic substances by preparing an oxidation solution by mixing ammonium persulfate ((NH4)2S2O8) with distilled water, as it does not use sulfuric acid. In addition, by using lignocellulosic carbon, it is an environmentally friendly and sustainable raw material that is cheaper than graphite, and since it does not generate salt during the graphene manufacturing process, it has the effect of being able to produce amorphous graphene with antibacterial functions in an environmentally friendly manner.

[0085] Furthermore, by omitting the reduction process (no reducing agent) in the step of forming graphene oxide, the amorphous properties of the graphene oxide can be better maintained. Additionally, by omitting the reduction process, the process is simplified, manufacturing costs and time can be saved, and graphene can be manufactured using a more environmentally friendly process since no additional chemicals (reducing agents) are used.

[0086] The present invention, as described above with reference to the attached drawings, is capable of various modifications and alterations by a person skilled in the art, and such modifications and alterations should be interpreted as being included within the scope of the rights of the present invention.

Claims

Claim 1 A raw material preparation step (S1) for preparing lignocellulosic carbon; an oxidation solution preparation step (S2) for making an oxidation solution by dissolving ammonium persulfate ((NH4)2S2O8) in distilled water; a graphene oxidation solution manufacturing step (S3) for forming graphene oxide by mixing lignocellulosic carbon and the oxidation solution; and a graphene dispersion step (S4) for making a mixed solution by adding a dispersion solution containing spherical nanocellulose crystals with hydrophobic properties and ethanol to the graphene oxidation solution and mixing them. and a heat treatment step (S5) of maintaining the mixed solution at a high temperature for a predetermined time and cooling it after the graphene dispersion step (S4); wherein the woody carbon is manufactured by a pretreatment process of drying and grinding a raw material selected from wood, bamboo, and coconut shells; a carbonization process of carbonizing at 400 to 800°C for about 1 to 3 hours; an activation process of activating the carbon by heating at 700 to 1,000°C using CO2 or steam; and a process of cooling and washing the woody carbon after activation to remove impurities and drying it; wherein the graphene oxide solution manufacturing step (S3) maintains amorphous characteristics by omitting the reduction process of graphene oxide without adding a reducing agent, and is composed of woody carbon and ammonium persulfate, an oxidizing agent, in a weight ratio of 1:2, and when the woody carbon is based on 10g, the oxidation solution contains 0.3 to 0.3g of ammonium persulfate ((NH4)2S2O8). It is contained at a molarity of 0.5, and in the graphene dispersion step (S4), the dispersion solution is added in an amount of 8 to 12 weight% of the weight of the graphene oxide solution, wherein the dispersion solution comprises 0.5 to 1.0 weight% of hydrophobic spherical nanocellulose crystals and sodium dodecyl sulfate (CH3(CH2) 10 A method for manufacturing amorphous graphene comprising 0.2 to 0.5 wt% of CH2OSO3Na), 75 to 85 wt% of ethanol, and 14 to 20 wt% of water, wherein the heat treatment step (S5) is characterized by promoting the formation of amorphous graphene by performing high-temperature heat treatment at a temperature between 200 and 400°C for 1 to 2 hours in an oxygen-free atmosphere, and then rapidly cooling to a temperature of 0°C or lower. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A product comprising amorphous graphene produced by the graphene manufacturing method of claim 1, wherein the amorphous graphene is coated on at least a portion of the surface of the product, and the amorphous graphene is characterized in that the ID / IG ratio, which is the ratio of the intensity of the D band to the G band during Raman spectroscopic analysis, is 1 or greater, and the zeta potential is +70mV or greater.

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