GRAPHITE-LIKE CARBON MATERIAL FROM MELANOIDINS AND PREPARATION THEREOF

Abstract

38576 The present disclosure pertains to a process for the preparation of graphite—like carbon material from melanoidins comprising: a. extracting melanoidins from food products waste material, and b. Pyrolyze the extracted melanoidin at a temperature of to 1200°C, at inert atmosphere. The resulting material is used as hard carbon material and as a precursor for graphite, graphene, graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof.

Description

38576 GRAPHITE-LIKE CARBON MATERIAL FROM MELANOIDINS AND PREPARATION THEREOF Field The present disclosure is directed to graphitelike carbon mate rial from melanoidins and the preparation thereof. More particu larly, it is directed to a method for Producing HighQuality Ni trogenDoped GraphiteLike Carbon Materials from Extracted Mela noidins of Spent Coffee Grounds via MicrowaveAssisted Pyrolysis under Vacuum Conditions Background Graphitelike carbon materials encompass a range of carbon materi als that share structural similarities with graphite, specifically the layered arrangement of spZhybridized carbon atoms. Graphite like materials include hard carbon, graphite, graphene, graphene oxide, carbon nanotubes, graphene quantum dots, and graphitic car bon nitride quantum dots, all of which feature layered or gra phitic structures. Materials with layered structures often exhibit anisotropic electronic properties, which can be advantageous in various applications. Layered materials can possess high tensile strength along the plane of the layers, useful in composite mate rials. These properties make graphitelike carbon material suita ble for use in electrical devices such as energy storage devices and batteries, but also as catalyst and in composite materials. Graphitelike carbon materials, such as hard carbon and graphite, are essential components in energy storage devices, electronics, and composite materials due to their excellent electrical conduc tivity, mechanical strength, and chemical stability 1 38576 Hard carbons are complex structures made up of graphitelike lay ers, orientated randomly, forming a mixture of stacks, sheets, pores and nanopores. The sheets comprise turbotratic graphene lay ers, leading to a complex structure with micropores and nanopores. This structure provides a high surface area and high electrical conductivity. Hard carbon is often used as electrode material for batteries, as catalysts or in polymer coatings, and is suitable for supercapacitor electrodes. Graphite consists of sheets of trigonal planar carbon. The indi vidual layers are called graphene. In each layer, each carbon atom is bonded to three other atoms forming a continuous layer of sp2 bonded carbon hexagons, like a honeycomb lattice with a bond length of 0.142 nm, and the distance between planes is 0.335 nm. Graphite consists of many stacked layers of graphene, typically in the excess of hundreds of layers. Bonding between layers is rela tively weak van der Waals bonds, which allows the graphenelike layers to be easily separated and to glide past each other. Elec trical conductivity perpendicular to the layers is consequently about 1000 times lower. Synthetic and natural graphite are con sumed on a large scale (1.3 million metric tons per year in 2022) for uses in many critical industries including refractories (50%), lithiumion batteries (18%), foundries (10%), lubricants (5%), among others (17%) In very basic terms graphene could be described as a single, one atom thick layer of the commonly found mineral graphite. Graphene like materials are also used as electrode materials in electrical devices, for instance in lithium batteries. Materials with a sheetlike structure such as graphene are in high demand, but its production normally requires high energy consuming processes. 2 38576 Graphene Oxide is derived from graphite and retains a layered structure with oxygencontaining functional groups. Carbon Nanotubes are essentially rolledup graphene sheets and share the spZhybridized carbon structure, of graphitelike mate rials. Graphene carbon quantum dots are carbon particles with graphene structure in nanosize. Graphene carbon quantum dots are small fragments of graphene and possess layered structures The graphene quantum dots are usually surfacefunctionalized and have a tunable fluorescence, are highly sensitive to environment and have photo chemical properties. Graphene carbon quantum dots may be applied in bioimaging, solar energy harvesting, nanosensing, lightemit ting devices and photocatalysts. Graphitic Carbon Nitride Quantum Dots contain nitrogen in a lay ered, graphiticlike structure. Traditional methods for producing graphitelike carbon materials from biomass involve the direct pyrolysis or carbonization of whole biomass materials, including Spent Coffee Grounds (SCG). These methods present several challenges: . Heterogeneous Composition of SCG: Whole SCG contains lipids, cellulose, hemicellulose, lignin, and other impurities that interfere with efficient carbonization and graphitization. 0 High Processing Temperatures and Times: Due to the complex matrix of SCG, higher temperatures (often exceeding 2500°C) and longer processing times are required, leading to in creased energy consumption. . Inconsistent Material Properties: The presence of impurities can result in carbon materials with variable and inferior properties. 3 38576 So far numerous attempts have been made to create graphitelike carbon materials from biomass. For instance several publications describe the use of spent coffee grounds for the preparation of hard carbon materials: For instance CN111204731 describes sodium ion batteries, and a preparation method of a hard carbon negative electrode material of a sodium ion battery. The pure hard carbon negative electrode ma terial is prepared through an ash removal process and a carboniza tion process. CN115140725 relates to a preparation method of a coffeeground based Fey'and Fe'ion doped biochar material for hydrogen produc tion. The preparation method comprises activating coffee grounds, pyrolysis of the coffee grounds and a hydrothermal treatment. CN106784832 discloses a preparation method for porous carbon mate rials from coffee grounds. The porous carbon material is used as anode material of lithiumion batteries. CN105217629 discloses a preparation method for the activation of carbon from coffee ground. The preparation method comprises de greasing the coffee grounds by vacuum pyrolysis and subsequent ac tivization using phosphoric acid. The degreasing is said to avoid clogging of the activated carbon pores. KR20180038802 relates to a method for preparing heteroatomdoped carbon materials using spent coffee grounds, which can be used as an electrode material of a fuel cell, a super capacitor or a redox flow battery by preparing nitrogendoped carbon materials by acti vating spent coffee grounds. Optionally the material is also doped with boron by addition of a boron precursor. CN109970058 discloses a preparation method of coffee ground sub strate active carbon by soaking the coffee grounds, drying and 4 38576 subsequently treating the coffee grounds with 812 % phosphoric acid solution assisted with ultrasonic treatment. Subsequently the coffee grounds are heated in a furnace at 580620 °C. The active carbon is used for treating waste water with Cr(VI), adsorbing Cr and preventing and treating heavy metal pollution. WO2021154332 concerns biomassderived activated carbon for use in fabricating energy storage devices, such as supercapacitors. Pro cesses for preparing activated carbon from biomass using a potas sium hydroxide treatment using nitrogendoping. The biomass may be spent coffee grounds. The biomass is precarbonized by heat treat ment under nitrogen atmosphere and chemically activating and cal cining the precarbonized biomass with KOH and heating at a tem perature between 6001200 °C under nitrogen or argon atmosphere. Then washing the carbonized biomass with hydrochloric acid. CN 111892048 describes a palmbased artificial graphite and a pre paration method thereof by: 1. screening palm shells, drying and crushing the qualified palm shells to obtain palmbased driving body powder; mixing asphalt and tire oil in proportion to obtain a mixture of asphalt and tire oil; 2. mixing the palmbased driving body powder and the asphalt tire oil mixed liquid to obtain a mixture; 3. fermenting the mixed material with the catalyst to obtain the fermentation mixed material; and 4. sequentially subjecting the fermentation mixture to thermal cracking and graphitization to obtain palmbased artificial graphite. An overview of Carbon nanodots is given in J. of Carbon Research, 2018, 4, 67, pp. 135 and in Materials Today 2021, Vol 51, pp.13827. 5 38576 With the process according to the present disclosure we provide high quality graphitelike carbon material by a process that is both environmentally and economically sustainable, has optimal en ergy consumption and provides graphitelike carbon materials with high nitrogen content and can doped with additionally other het eroatoms. Further, with the present disclosure we provide high quality and consistent graphitelike carbon materials such as hard carbon, graphite and graphene at much lower temperatures and better struc ture / properties from biomass by focusing on melanoidins and in particular coffee melanoidins as precursors. Summary The present disclosure is directed to a process for the prepara tion of graphitelike carbon material from melanoidins comprising: a. extracting melanoidins from food products waste material, and b. Pyrolyze the extracted melanoidin at a temperature of 500 to 1200°C, at inert atmosphere. The melanoidin subjected to the pyrolyzation step b may be mela noidin or a salt thereof, preferably a sodium of potassium salt of melanoidin. The resulting material may suitably be used as hard carbon mate rial or as a precursor for graphite, graphene or other graphite like carbon material with higher ordered structures than hard car bon material such as graphene carbon quantum dot material, carbon nanotubes and graphitic carbon nitride graphenelike material or combinations thereof 6 38576 In one embodiment the melanoidin is contacted with dopant precur sor prior to the pyrolyzation of step b. Preferably the dopant precursor is a nitrogen precursor such as urea or melamine It is advantageous to contact the melanoidin with a metal catalyst prior to the pyrolyzation of step b. Suitable metal catalysts are iron or nickel salts. In said process after the pyrolyzation step b a postpyrolyzation step may be conducted wherein the pyrolyzed extracted melanoidin is heat treated at a temperature of between 1000 and 3000 °C, preferably at a temperature of between 1000 and 2000 °C, most preferably at a temperature between 1000 and 1600 °C, in inert at mosphere. Said postpyrolized melanoidin comprises graphite. The extraction of the melanoidin may be conducted by alkaline treatment of the food products waste material. Optionally a pretreatment is conducted on the food products waste material. Said pretreatment is conducted either simultaneous or prior to the extraction of the melanoidins. Examples of pretreatment comprises ultrasonic treatment, subcrit ical water hydrolysis (SCWH), microwave treatment and / or chemical treatment with either acid or alkaline, preferably ultrasonic treatment. The graphitelike carbon material obtained after postpyrolyzation of melanoidin may be used as such (as graphite), but the material may also be used as precursor for the preparation of graphene, graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof. 7 38576 To this end the postpyrolyzed melanoidin is further treated to form graphene or graphenelike material or combinations thereof. The graphenelike material comprises graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof These further treatments comprise chemical vapor deposition (CVD), pyrolysis, exfoliation techniques or combinations thereof may be used. Also hydrothermal treatment, solvothermal, or microwaveas sisted methods, or combinations thereof The process according to the disclosure provides novel graphite like carbon material. The present disclosure is also directed to this novel graphitelike carbon material obtainable by the methods according to the disclosure. Said graphitelike carbon material comprises pyrolyzed melanoidin which is formed into hard carbon material. The present disclosure also provides novel graphitelike material that has been further processed into graphite, graphene and other graphenelike material such as graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof. 8 38576 Detailed Description As described above, the present disclosure is directed to a pro cess for the preparation of graphitelike carbon material from melanoidins comprising: a. extracting melanoidins from food products waste material, and b. Pyrolyze the extracted melanoidin at a temperature of 500 to 1000°C, at inert atmosphere. The preparation of graphitelike carbon materials from melanoidins has not been described in the prior art. With inert atmosphere is meant both an atmosphere of inert gas, but also vacuum atmosphere is suitable. Said vacuum pyrolysis treatment may be conducted in conventional heating devices such as furnaces but also in a microwave. The pressure used varies from 0.10.01 MPa. The reaction time after reaching the targeted tem perature ranges from 0.51 hour Melanoidins are a class of brown, hydrophilic nitrogencontaining polymers which are formed during the thermal processing of foods such as coffee, cocoa, bread, malt, barley, Brewers Spent Grain (BSG), soy, meat, and honey. Although the melanoidins can be ob tained from various food products waste material, the use of spent coffee grounds and the brewers spent Grain is preferred since it has a very high melanoidin content, with Spent Coffee grounds hav ing the highest preference. Thus, melanoidins are complex, nitro genrich polymers formed during the Maillard reaction during for instance coffee roasting. 9 38576 During thermal processing of food products as described above, amino acids and reducing sugars, such as aldose and dxylose, re act to form what are termed initial Maillard reaction products. Under continued heating, melanoidins are formed by cyclizations, dehydrations, retroaldolizations, rearrangements, isomerizations and condensations of those initial Maillard reaction products. The complexity of the Maillard reaction pathways results in a range of final reaction products, with inter alia the time of heating, type of heating, temperature, initial chemical composition of the sys tem, moisture content, water activity and pH value being determi native of the final composition. Utilizing melanoidins specifically exploits their high nitrogen content and aromatic structure, which enhances the properties of the resulting carbon materials compared to those derived from whole spent coffee grounds or other biomass. These specific struc tural properties of melanoidin increase the electrical and thermal conductivity of the resulting graphitelike carbon material. In general, the use of extracted melanoidins as precursor for graphitelike carbon materials maximizes the value derived from SCG, supporting circular economy principles. By separating valua ble components, less residual waste remains, reducing environmen tal impact. By isolating melanoidins from for instance spent coffee grounds (SCG), impurities such as lipids, cellulose, hemicellulose, and lignin are removed. This results in a purer precursor that leads to more consistent and highquality carbon materials. Furthermore, whole spent coffee grounds contain various compounds that may in terfere with the carbonization and graphitization processes that take place during pyrolysation, such as residual oils and carbohy drates. Extracting melanoidins minimizes these interferences, al lowing for more controlled synthesis. 10 38576 Since melanoidins have a threedimensional network of aromatic and aliphatic chains, with frequent crosslinking through CC, CO, and CN bonds, it provides the ideal foundation for carbonization, as it creates a structurally robust precursor. It has a relatively high carbon content and a lower oxygen content compared to other biomass materials. Furthermore, its spZhybridized carbon struc ture structure of the aromatic moieties, provides an excellent precursor for the formation of graphitelike structures. The resulting material may suitably be used as hard carbon mate rial or as a precursor for graphite, graphene or other graphite like carbon material with higher ordered structures than hard car bon material such as graphene carbon quantum dot material, carbon nanotubes and graphitic carbon nitride graphenelike material or combinations thereof. Melanoidins have a higher nitrogen content compared to whole Spent coffee grounds. Nitrogen atoms become incorporated into the carbon 1attice during pyrolyzation, resulting in nitrogendoped carbon materials. The inherent nitrogen content of melanoidins enables insitu doping during pyrolysis, improving electrical conductivity and eliminating the need for external doping agents. Since the original structure of melanoidins allows for the pres ence of heteroatoms such as nitrogen, oxygen and sulphur, it is also possible to incorporate additional heteroatoms into the graphitelike carbon material by doping. The melanoidin may for instance be contacted with dopant precursor prior to the pyrolyza tion of step b. Preferably the dopant precursor is a nitrogen pre cursor such as urea or melamine. The use of a dopant precursor en sures the incorporation of the nitrogen into the carbon structure. In addition to nitrogen also sulfur or phosphorus precursors may be used. 38576 The melanoidin used in the process according to the disclosure may be melanoidin or a salt thereof, preferably a sodium of potassium salt of melanoidin. These salts were found to act as activating agents creating more porous structures beneficial for applications like energy storage and adsorption. In addition, potassium and so dium ions were found to facilitate the formation of graphitic structures, enhancing the degree of graphitization. Prior to the the pyrolyzation of step b the melanoidin may also be contacted with metal catalysts such as iron and nickel salts. These metal catalyst were found to catalyze the graphitation pro cess. The reactive functional groups and heterocyclic structures in mel anoidins lower the activation energy needed for pyrolization to graphitelike carbon material. This allows for synthesis at lower temperatures and shorter reaction times compared to using whole SCG. Lower processing temperatures translate to reduced energy consumption, making the production process more costeffective and environmentally friendly. Furthermore the aromatic rings in mela noidins contain carbon atoms with sp2 hybridization, which is critical for forming graphitic and graphiticlike materials. The abundance of functional groups in melanoidins also allows for eas ier functionalization of the carbon materials, enabling customiza tion for specific applications. In short the key advantages if the process according to the de cription are: . Enhanced Material Properties: Produces nitrogendoped carbon materials with superior electrical conductivity, structural integrity, and consistency. 12 38576 0 Process Efficiency: Achieves carbonization and graphitiza tion at lower temperatures and shorter times compared to traditional methods. . Sustainability: Utilizes waste materials effectively, re duces energy consumption, and contributes to environmental sustainability. In said process optionally after the pyrolysation step b a post pyrolization step may be conducted wherein the pyrolyzed extracted melanoidin by a heat treatment at a temperature of between 900 and 3000 °C preferably at a temperature of between 1000 and 2000 °C, most preferably at a temperature between 1000 and 1600 °C, in in ert atmosphere. Said postpyrolized melanoidin comprises graphite. The postpyrolysis heat treatment is conducted for 14 hours after reaching the target temperature under vacuum or inert atmosphere to enhance graphitic ordering. This is very short in comparison with the reaction time needed for conversion of whle spent Coffee grounds, which is up to 12 hours. It was found that the postpyrolyzation step to form graphite can be conducted at lower temperatures than with conventional graphite production processes. Without wishing to be bound to a theory we believe that the presence of the aromaticring structures of mela noidin facilitates graphitization. Also the presence of metal cat alyst reduces the required graphitization temperature. Also the presence of potassium and sodium ions originating from melanoidin salts were found to facilitate the formation of graphitic struc tures, enhancing the degree of graphitization. Thus, it was found that the postpyrolysation can be conducted at temperatures as low as between 1000 and 1600 °C. 38576 It is also possible to dope the pyrolyzed melanoidin with dopant or metal catalyst prior to the postpyrolysation, but it is pre ferred to do so prior to the pyrolyzation step b, because it avoids unwanted evaporation and / or decomposition. The graphitelike carbon material obtained after postpyrolyzation of melanoidin may be used as such (as graphite), but the material may also be used as precursor for the preparation of graphene, graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof. To this end the postpyrolyzed melanoidin is further treated to form graphene or graphenelike material or combinations thereof. The graphenelike material comprises graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof These further treatments comprise chemical vapor deposition (CVD), pyrolysis, exfoliation techniques or combinations thereof may be used. Also hydrothermal treatment, solvothermal, or microwaveas sisted methods, or combinations thereof. Optionally, the extraction of the melanoidin is conducted by alka line treatment of the food products waste material. Said alkaline treatment may involve treatment with potassium hydroxide or sodium hydroxide. This will openup the food product waste structure, making the extraction of the melanoidins more effective, but also melanoidin salts will be formed. As mentioned above, these mela noidin salts create the formation of a more porous structure, and catalyse graphitic formation Optionally a pretreatment is conducted on the food products waste material. Said pretreatment is conducted either simultaneous or prior to the extraction of the melanoidins. These treatments help 14 38576 the extraction of the melanoidins from the food products waste ma terial. Examples of pretreatment comprises ultrasonic treatment, subcrit ical water hydrolysis (SCWH), microwave treatment and / or chemical treatment with either acid or alkaline, preferably ultrasonic treatment. Ultrasonic treatment has the following advantages: Ultrasonication disperses melanoidin particles uniformly in the reaction medium, ensuring consistent heat transfer and reaction conditions during carbonization. The mechanical effects of ultrasound reduce the particle size of melanoidins, increasing the surface area and ex posing more reactive sites. This enhances the efficiency of the carbonization process. Ultrasound promotes mass transfer by creating microjets and shockwaves, facilitating the removal of volatile com pounds and promoting the formation of a more ordered car bon structure. Ultrasonication prevents the aggregation of particles, leading to more uniform and higherquality carbon nano materials. The process according to the disclosure provides novel graphite like carbon material. The present disclosure is also directed to this novel graphitelike carbon material obtainable by the methods according to the disclosure. Said graphitelike carbon material comprises pyrolyzed melanoidin which is formed into hard carbon material. The present disclosure also provides novel graphitelike material that has been further processed to graphite, graphene and other graphenelike material such as graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof. 15 38576 Hard carbon is often used as electrode material for batteries, as catalysts or in polymer coatings and supercapacitor electrodes. This means that generally a high surface area and high electrical conductivity is desired. The process according to the present dis closure allows for the production of hard carbon material with a homogeneous pore structure and very high surface area. The use of melanoidins as a precursor for this material offers a more uniform precursor compared to the heterogeneous mixture present in whole SCG. This uniformity leads to better control over the size, mor phology, and structural properties of the synthesized carbon mate rials. In addition to that, the abundance of functional groups in melanoidins allows for easier functionalization of the carbon ma terials, enabling customization for specific absorption or cata lyst applications. As explained above, the electrical conductivity of the hard carbon material is higher than material obtained from whole spent coffee grains, because of its high nitrogencontent and optionally other heteroatoms. The hard carbon material ob tained with the process according to the disclosure, is also suit able for use as electrode material for sodium ion batteries. This is important because of the increased demand of lithium due to global environmental issues and rising oil prices. The abundant and widely distributed sodium resources make sodiumion batteries (SIBs)lowcost and are considered to be one of the most promising largescale energy storage technologies. At present, the conventional negative electrode material of lith ium ion battery is graphite, but the radius of sodium ion is larger than that of lithium ion (0.072 nm for Li+ and 0.102 nm for Na+), so it cannot be embedded in graphite, so the negative elec trode of sodium ion battery can only choose materials with larger interlayer spacing. Hard carbon prepared with the process accord ing to the present disclosure was found a suitable candidate for 16 38576 carbonaceous materials for SIBs because of the following ad vantages: low cost, low operating voltage (~0 V vs. Na+ / Na), and high capacity. Since with the process according to the present disclosure a material can be made wherein the pore structure and interlayer space can be set, hard carbon material according to the present disclosure is highly suitable for use as electrode for SIBs. As mentioned above, the graphite prepared with the processes ac cording to the invention can suitably used for all known applica tions for advanced graphite owing to its high quality, high elec trical conductivity, high surface area and mechanical strength. Graphene and other graphenelike material such as graphene carbon quantum dot material, carbon nanotubes, graphitic carbon nitride quantum dots, graphene oxide or combinations thereof can be made using the graphite according to the present disclosure as a pre cursor. Graphene may be prepared from the graphitelike carbon material of the present disclosure by methods such as chemical vapor deposi tion (CVD), pyrolysis, or exfoliation techniques. Also combina tions of these methods may be used. For instance in the Pyrolysis and Exfoliation method generally carbonization by pyrolyzation of the precursor is followed by me chanical or chemical exfoliation to produce graphene sheets. In the Ultrasound Exfoliation method ultrasonication of carbonized materials (i.e. pyrolyzed material) to produce fewlayer graphene. The graphene produced may be formed into carbon nanotubes and graphene oxide or combinations thereof. The graphene carbon quantum dots CQDs may be synthesized using the graphite or graphene prepared according to the pressent processes 17 38576 by using hydrothermal, solvothermal, or microwaveassisted meth ods, where controlled reaction conditions allow for precise size and surface property tuning. The Hydrothermal / Solvothermal synthe sis offers precise control over particle size and functionaliza tion. This preparation method is suitable for producing CQDs with specific properties. MicrowaveAssisted synthesis provides rapid heating and uniform energy distribution, leading to shorter reaction times and high quality CQDs. The CQDs according to the present disclosure may suitably be used in electrooptical devices, sensors, energy stor age devices, and quantum computing and communication: . Optoelectronic Devices: the CQDs have unique optical and electronic properties, such as sizetunable photolumines cence and quantum confinement effects, making them suitable for optoelectronic applications like LEDs, photodetectors, and solar cells. o Sensors: the CQDs may be used in sensitive and selective sensors for detecting gases, chemicals, or biological agents, which are crucial in edge devices that require real time monitoring and data processing. . Energy Storage: The CQDs may enhance the performance of su percapacitors and batteries by improving electrode materi als, contributing to efficient energy management in edge de vices. 0 Quantum Computing and Communication: The CQDs have potential applications in quantum dotsbased gubits for quantum compu ting, which may be relevant for advanced edge computing technologies. Below the disclosure is illustrated by the following non limiting examples. EXAMPLES 18 38576 Pretreatment of SCG . Collect spent coffee grounds and dry them to reduce moisture content. o Optionally, subject the SCG to ultrasonic treatment by im mersing in water or an alkaline solution and applying ultra sonic waves at a frequency of 2040 kHz for 3060 minutes. This disrupts the biomass structure and enhances extraction efficiency. Alkaline Extraction o Prepare an alkaline solution using sodium hydroxide (NaOH) at a concentration of 0.11 M} o Mix the pretreated SCG with the alkaline solution at a solidtoliquid ratio of 1:101:20 (w / v). . Stir the mixture at 5080°C for 13 hours to extract mela noidins. 0 Filter the solution to separate the liquid extract contain ing melanoidins from the residual biomass. o Neutralize the extract with hydrochloric acid (HCl) to pre cipitate melanoidins if necessary. Advantages of Melanoidin Extraction as conducted above: o Removes impurities such as lipids, cellulose, and lignin present in whole SCG. o Yields a purified melanoidinrich fraction with high nitro gen content and aromatic structures, facilitating efficient carbonization and graphitization. Microwaveassisted pyrolysis under vacuum a. Preparation of Extracted Melanoidins 19 38576 . Dry the extracted melanoidins to obtain a solid precursor. b. MicrowaveAssisted Pyrolysis . Place the dried melanoidins into a vacuum chamber suitable for microwave processing. o Evacuate the chamber to achieve a vacuum of 0.10.01 MPa. . Apply microwave irradiation at appropriate power levels: o For industrialscale batches (13 tons), use approxi mately 450kW of microwave power. 0 For smallscale batches (e.g., 1kg), use 1.53kW of microwave power. o Heat the melanoidins to a temperature of 5001200°C within 1060 minutes, depending on the batch size. o Maintain the target temperature for 0.51 hour to ensure complete pyrolysis. Advantages of MicrowaveAssisted Pyrolysis Under Vacuum as con ducted above: . Efficient heating due to the inherent microwave absorption properties of melanoidins. . Uniform temperature distribution, reducing thermal gradients and enhancing material quality. . Vacuum conditions facilitate the removal of volatiles and prevent oxidation, preserving nitrogen content for insitu doping. Postpyrolysis heat treatment a. Graphitization Enhancement . Transfer the pyrolyzed melanoidin material to a hightemper ature furnace. 0 Heat under vacuum or inert gas atmosphere to temperatures between 10001600°C. 20 38576 Maintain the temperature for 14 hours to promote graphitic ordering. ages of graphitization enhancement as conducted above: Enhances electrical conductivity and mechanical strength. Achieves highquality graphitelike structures at lower tem peratures compared to conventional methods. 21

Claims

l. Method for the preparation of graphite-like carbon material of melanoidins, comprising: a. the extraction of melanoidin from waste material of food products, and b. pyrolyzing the melanoidin at a temperature of 500 up to 1200 °C, in an inert atmosphere.

2. Method according to claim l, whereby the melanoidin that to the is subjected to pyrolysis step b, is a salt of melanoidin, preferably a sodium or potassium salt of melanoidin.

3. Method in accordance with claim 1 or 2, whereby the resulting The material is used as hard carbon material.

4. Method of working in accordance with one of the preceding claims 13, whereby the resulting material is used as a precursor for the preparation of graphite, graphene, graphene-carbon quantum dot material, carbon nanotubes, graphite carbon nitride quantum dots, graphene oxide or combinations thereof.

5. Proceedings pursuant to one of the preceding claims 14, whereby the melanoidin is brought into contact with dopant precursor before the pyrolysis of step b.

6. Process under claim 5, in which the dopant precursor a is a nitrogen precursor, such as urea or melamine. 22 7. Proceedings pursuant to one of the preceding claims 16, whereby the melanoidin is brought into contact with a metal catalyst before the pyrolysis of step b.

8. Process according to claim 7, in which the metal catalyst is an iron or is nickel salt.

9. Method of working in accordance with one of the preceding claims 18, whereby after the pyrolysis step b a postpyrolysis step is performed, whereby The pyrolyzed melanoidin from step b is subjected to a heat treatment at a temperature between 1000 and 3000 °C, at preferably at a temperature between 1000 and 2000 °C, most at preferably at a temperature between 1000 and 1600 °C, in an inert atmosphere.

10. Method according to claim 9, whereby the resulting item includes pyrolyzed melanoidin graphite.

11. Method of working in accordance with one of the preceding claims, whereby the Extraction of the melanoidin is performed by alkaline treatment of waste material from food products.

12. Proceedings pursuant to one of the preceding claims whereby a pretreatment is performed on the waste material of the food products, either simultaneously or prior to the extraction of the melanoidins 13. Process according to claim 12 where the pretreatment is ultrasonic treatment, subcritical water hydrolysis (SCWH), microwave treatment and / or chemical treatment with acid or alkali includes, preferably, ultrasonic treatment. 23 14. Proceedings pursuant to one of the preceding claims regarding the item pyrolyzed melanoidin is further treated to graphene or to form graphene-like material or combinations thereof.

15. Process under claim 14, involving the graphene-like material graphene carbon quantum dot material, carbon nanotubes, graphite carbon nitride quantum dots, graphene oxide or combinations thereof includes 16. Process under claim 14 or 15, where the post-pyrolyzed melanoidin is further treated by hydrothermal, solvothermal or microwave-assisted methods, or combinations of them.

17. Process pursuant to claim 10, whereby the pyrolyzed or post Pyrolyzed melanoidin is further treated to graphene-like to form material by chemical vapor deposition (CVD), pyrolysis, exfoliation techniques or combinations thereof.

18. Graphite-like carbon material obtainable by the process according to one of the preceding claims 118.

19. Graphite-like carbon material containing pyrolyzed melanoidin includes 20. Graphite-like carbon material according to claim 18 or 19, comprising hard carbon material, 21. Graphite-like carbon material comprising melanoidin that is subject to pyrolysis and postpyrolization. 24 Graphite-like carbon material as per claim 21, comprising bicycle Graphite-like carbon material according to claim 21 or 22, that is subjected to further processing to graphene or graphene-like to form material, such as graphene carbon quantum dot material, carbon nanotubes, graphite carbon nitride quantum dots, graphene oxide combinations thereof. 25