Obtaining microfibrillated cellulose from vegetable waste through ball milling assisted by acid hydrolysis.

Description

1 / 14 “OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE RESIDUES THROUGH BALL MILLING AND ACID HYDROLYSIS ASSISTED”

[001] This patent application relates to a process for producing microfibrillated cellulose extracted from plant waste. Specifically, the present invention relates to obtaining microfibrillated cellulose from pineapple peel waste (Ananas camosus), cowpea pod husk (Vigna unguiculata) and corn straw (Zea mays L) through a chemomechanical process, with a chemical step of acid hydrolysis and bleaching, in addition to a mechanical step using ball milling, with potential application in the food, medicinal, civil and agronomic industries, presenting itself as an alternative for the use of plant waste, adding value to the by-product that is usually disposed of improperly, and consequently, causes damage to the environment.

[002] Cellulose has been gaining prominence as the most abundant polymer in nature, found primarily in plant cell walls. This biopolymer is composed of long chains of β-d-glucopyranose units linked by β-1,4-glycosidic bonds, forming a dimer structure (CHEN, J., ZHAO, L., LING, J., YANG, L., OUYANG, X. A quaternized chitosan and carboxylated cellulose nanofiber-based sponge with a microchannel structure for rapid hemostasis and wound healing. International Journal of Biological Macromolecules, Zhoushan v. 233, p. 123631, Apr. 2023).

[003] Cellulose is used in a wide variety of applications, which is encouraged by its renewable and biodegradable characteristics. In the industrial sector, cellulose is generally used in smaller fractions, on a micro and nano scale, from the isolation of nano / microcellulose (NC / MC). To be classified as nanocellulose, at least one physical dimension must be smaller than 100 nm; above this value, it is classified as microcellulose. The study of NC / MC has gained scientific attention because it can Petition 870250000472, dated 03 / 01 / 2025, page 7 / 30 2 / 14 can be used in various areas, such as: food industry, civil construction, agronomy, health, etc. With NC / MC, it is possible to obtain various morphologies, including fibers, crystals, rods and whiskers, each with specific characteristics and dimensional properties. (VARSHNEY, S.; MISHRA, N.; GUPTA, M. Progress in nanocellulose and its polymer based composites: A review on processing, characterization, and applications. Polymer Composites, Prayagraj, v. 42, n. 8, p. 3660-3686, May 2021)

[004] The three main categories are: nano / microfibrillated cellulose (NFC / MFC), nano / microcrystalline cellulose (NCC / MCC), and bacterial nano / microcellulose (NB / MB). For the isolation of NC from cellulose fibers, there are several methodologies, some of the most common being acid hydrolysis; homogenization by grinding; and mixed or chemical-mechanical methods. As a way to reduce the disadvantages that chemical-mechanical processes present in isolation, the literature recommends the use of combined processes, identified as an environmentally effective method to promote NFC / MFC (SHARMA, A.; THAKUR, M.; OLIVEIRA, M.; SOUZA, T.; GOSWAMI, S. Commercial application of cellulose nanocomposites - a review. Biotechnology Reports, Mohali, v. 15, n. 21, p. e00316, Mar. 2019; WU, C.; MCCLEMENTS, D.; HE, M.; HUANG, Y.; ZHU, H.; JIANG, L.; TENG, F.; LI, Y. Okara nanocellulose fabricated using combined chemical and mechanical treatments: structure and properties. Journal of Molecular Liquids, Harbin, v.335, p. 116231, Aug. 2021; QIAN, M.; LEI, H.; OLIVEIRA, E.; ZHAO, Y.; WANG, C.; HUO, E.; ZHANG, Q.; OLIVEIRA, W. High-yield production of nanocrystalline cellulose by microwave-assisted dilute acid pretreatment combined with enzymatic hydrolysis. Chemical Engineering and Processing - Process Intensification, Richland, v.160, p. 108292, Mar. 2021).

[005] In view of this, vegetables with potential for reuse include pineapple (Ananas camosus), cowpea pods (Vigna unguiculata) and corn (Zea mays L.), the routine consumption of such vegetables generates exorbitant amounts of waste from peels and pods, which Petition 870250000472, dated 01 / 03 / 2025, p. 8 / 30 3 / 14 are underutilized. Pineapple peel is composed of lignocellulosic structural molecules in an estimated proportion of 24% cellulose, 29% hemicellulose, and 6% lignin. Regarding beans and corn, Brazil is the third largest producer in the world. In the specific case of cowpea, the pods are rich in cellulose (29.97%), hemicellulose (24.33%), and lignin (7.31%). However, corn straw can contain 35-40% cellulose, 21-25% hemicellulose, and 11-19% lignin (PEREIRA, PHF; ORNAGHI, HL; OLIVEIRA, DM; PEREIRA, B.; ARANTES, V.; CIOF, MOH Effect of Chemical Treatment Sequence on Pineapple Peel Fiber: Chemical Composition, Thermal Stability and Thermal Degradation Kinetics. In Research Square, Guaratingueta, p.1-22, Jan. 2022; SANTOS, R.; BISPO, D.; GRANJA, H.; SUSSUCHI, E.; RAMOSB, A.; FREITAS, L. Pyrolysis of the Cowpea Bean Pod (Vigna unguiculata): Characterization of Biomass and Bio-Oil. Journal of Brazilian Chemical Society, São Cristovão, v. 31, n.1125-1136, jun. 2020; CHIN, K.; TING, SS; NGO, HL; OMAR, M. Surface functionalized nanocellulose as a veritable inclusionary material in contemporary bioinspired applications: A review. Journal of Applied Polymer Science, Avrau, v. 135, no. 13, p. 46065, apr. 2018).

[006] Some research has already explored the extraction of micro / nanocellulose by a chemical-mechanical process using ball milling. In one study, nanocellulose was extracted from paper egg trays from local biological waste using a chemical method followed by a mechanical ball milling process. The optimized alkaline acid (NaOH(10%)-H2SO4(65%)) was reported as the best percentage for extracting nanocellulose with almost no impurities (RUIWEN, Y.; PRABHAKAR, MN; DONG, WL; JUNGLL, S. Extraction and Characterization of Nano-cellulose from Local Waste Paper Egg Trays, Journal of Natural Fibers, Changwon, v. 19, n. 14, p. 8582-8592, sep. 2021).

[007] Microcellulose was also extracted from primary waste from the paper industry through chemical and mechanical isolation processes. The results showed similar chemical bonds in both treatments, which indicated Petition 870250000472, dated 03 / 01 / 2025, page 9 / 30 4 / 14 presence of cellulose and lignin. The morphology of the images showed a compact, nano-star-shaped structure with less agglomeration for chemical isolation. The mechanical process, however, presented structures in the form of nanoneedles. (SOUZA, AG; KANO FS; BONVENT JJ; ROSA DS Cellulose Nanostructures Obtained from Waste Paper Industry: A Comparison of Acid and Mechanical Isolation Methods. Materials Research, ABC Paulista, v. 20, n. 2, p. 209-214, jun. 2017).

[008] Maleic acid was used as a pretreatment before grinding raw sisal fiber balls to produce cellulose nanofibrils (CNFs). Pretreatment of unbleached sisal fibers has been reported to facilitate CNF fibrillation through cellulose depolymerization and dissolution of non-cellulosic cell wall components and non-crystalline cellulose. (WANG, Y.; YONGJJAN, Y.; HONGYING W.; YUANRU Y.; LIANGBIN Z.; ZHIJIAN T. Light-colored cellulose nanofibrils produced from raw sisal fibers without costly bleaching, Industrial Crops and Products, Changsha, v. 172, p. 114009, Nov. 2021).

[009] Cellulose paper and cellulose powder were used as sources for nanocellulose extraction, by coupling dry planetary milling with mild acid hydrolysis. It was found that the crystallinity and crystal size of ball-milled cellulose decreased with increasing ball milling time, and mild acid hydrolysis (47 wt% sulfuric acid) of ball-milled cellulose resulted in increased crystallinity and thermal stability of nanocellulose in the high-temperature range, without any alteration in chemical structure. (PHANTHONG, P.; GUAN, G.; MA, Y. HAO, X.; ABUDULA, A. Effect of ball milling on the production of nanocellulose using mild acid hydrolysis method, Journal of the Taiwan Institute of Chemical Engineers, Hirosaki, v. 60, p. 617-622, Mar. 2016).

[0010] Jute fibers were studied as a source for producing nanocellulose by the high-energy planetary ball milling process. The influence of various milling conditions, such as the nature of the milling (dry or wet), Petition 870250000472, dated 03 / 01 / 2025, page 10 / 30 5 / 14 Grinding time and ball size were studied in the particle size distribution and morphology of the obtained jute nanoparticles. Wet milling in deionized water resulted in particle size refinement with a small size distribution after 3 hours of milling. (BAHETI, VK; ABBASI, R.; MILITKY, J. Ball milling of jute fibre wastes to prepare nanocellulose. World Journal of Engineering, v. 9, n. 1, p. 45-50, feb. 2012).

[0011] Napier fiber (Pennisetum purpureum) functioned as a source for the fabrication of cellulose nanofibers (CNF) through ball milling assisted by acid hydrolysis. With acid hydrolysis of 5.6 M, the CNF presented the highest degree of crystallinity, greater thermal stability, and a fibrous network nanostructure was obtained. (RADAKISNIN, R.; ABDUL MAJID, MS; JAMIR, MRM; JAWAID, M.; SULTAN, MTH; MAT TAHIR, MF Structural, Morphological and Thermal Properties of Cellulose Nanofibers from Napier fiber (Pennisetum purpureum). Materials, Arau, v. 13, n. 18, p. 4125, sep. 2020).

[0012] Paper sludge was chemically treated with detergent and H2O2 and mechanically treated by grinding in: dry medium; wet medium with water and wet medium with ethanol, to obtain nanocellulose. The sample with wet grinding with ethanol showed higher yield and electrostatic stability in solution, in addition to not showing loss of crystallinity. Thus, isolation with ethanol was the most efficient process among those studied. (SOUZA, AG; KANO FS; BONVENT JJ; ROSA DS Cellulose Nanostructures Obtained from Waste Paper Industry: A Comparison of Acid and Mechanical Isolation Methods. Materials Research, ABC Paulista, v. 20, n. 2, p. 209-214, jun. 2017).

[0013] A study of the Sammaz-14 variety of corn cobs (Zea mays spp.) for the isolation of nanocelluloses using chemical and mechanical methods was reported. The isolated nanocrystals were corn cob (MC-NC) and corn cob nanofibers (MC-NF). The results showed that MC-NF is more thermally stable when compared to MC-NC. Morphological studies showed that MC-NC and MC-NF have needle-like structures, and that Petition 870250000472, dated 01 / 03 / 2025, p. 11 / 30 6 / 14 MC-NC has higher crystallinity. (JAMILA, BA; ABDULLAHI DANLADI, MMB; BEMGBA BN; PAUL MAMZA, ZBM; ABUBAKAR BM; IBRAHIM MI Extraction and Characterization of Cellulose Nanofibers and Nanocrystals from Sammaz-14 Maize Cobs Cells, Journal of Natural Fibers, Zaria, v. 19, n. 7, p. 2756-2771, Dec. 2022).

[0014] Another study reports the extraction of lignin-cellulose nanocrystals (LCNCs) from hemp waste. A homogeneous morphology of the hemp particles was obtained by ball milling. L-CNCs were obtained through mild acid hydrolysis of the ball-milled particles. The L-CNCs were used as filler in a polyvinyl alcohol (PVA) film, which produced a light-colored nanocomposite film with high UV protection capacity and enhanced tensile properties. In addition to these advantages, the nanocomposite film exhibited water vapor transmission properties comparable to commercial food packaging film, indicating potential applications. (ZHANG, Y.; ABU, NMAH; MARYAM, N. LigninCellulose Nanocrystals from Hemp Hurd as Light-Colored Ultraviolet (UV) Functional Filler for Enhanced Performance of Polyvinyl Alcohol Nanocomposite Films. Nanomaterials, Geelong, v. 11, n. 12, p. 3425, 2021).

[0015] Finally, sugarcane bagasse was used as a source for the extraction of cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF). Conventional hydrolysis was used to extract CNC, while ball milling was used to extract CNF. CNC showed a needle-like resemblance and CNF a rope-like resemblance. Furthermore, the amorphous portion was removed during hydrolysis; this resulted in an increase in the crystalline portion of CNC compared to CNF. However, CNF prepared by ball milling showed greater thermal stability. (SOFLA, MRKS; BROWN, RJ; TSUZUKI, T.; RAINEY, TJ A comparison of cellulose nanocrystals and cellulose nanofibers extracted from bagasse using acid and ball milling methods. Adv. Nat. Sci.: Nanosci. Nanotechnol, Hanoi, v. 7, n. 3, p. 035004, Jul. 2016). Petition 870250000472, dated 03 / 01 / 2025, page 12 / 30 7 / 14

[0016] Given what has been reported, it is possible to note that cellulose nanofibers have different applications in various technological sectors. In this context, the proposal for a production process that is less aggressive to the environment and that also uses raw materials from renewable sources, which are mostly discarded without proper reuse, causing possible environmental damage, is entirely consistent with market needs.

[0017] However, in order to demonstrate the mandatory condition of innovation, the applicants conducted extensive research on processes for obtaining nano / microfibrillated cellulose, the practical results of which revealed the existence of some applications with different extraction techniques. However, none of the inventions identified fully anticipates the proposal described in this patent application.

[0018] Patent CA2705970, entitled Cellulose nanofiber, production method of same and cellulose nanofiber dispersion, owned by the University of Tokyo, filed on August 26, 2008, refers to a method for producing cellulose nanofibers comprising steps of oxidizing cellulose in solution with the component 2,2,6,6-tetramethyl-1-piperidine-N-oxyl, an agent capable of oxidizing aldehyde groups. The fibers obtained from this production method are long and have demonstrated high strength indices.

[0019] Patent CA2831897, entitled Method for producing cellulose nanofibers, owned by TSUJI, S., filed on March 14, 2012, which describes a process for producing cellulose nanofibers comprising: step (A) oxidation of the cellulosic material in the presence of an N-oxyl compound; step (B) where the oxidized cellulosic material is formed into nanofibers by defibration; step (C-1) treatment of the cellulosic material in water with a hydroxide ion concentration of 0.75 to 3.75 mol / L, which occurs before step A, as a pretreatment; and step (C-2) Petition 870250000472, dated 03 / 01 / 2025, page 13 / 30 8 / 14 where the oxidized cellulosic material is subjected to hydrolysis in an alkaline solution, with a pH between 8 and 14, after step A and before step B.

[0020] Patent BR 112012000144-2, entitled “Process for producing microfibrillated cellulose”, owned by STORA ENSO OYJ, filed on July 2, 2010, describes a process for producing microfibrillated cellulose from a pretreatment of the fibers using enzymes (first enzymatic treatment), followed by a mechanical pretreatment of the fibers (first mechanical treatment). Then, the fibers undergo a second enzymatic treatment and a second mechanical treatment, in order to obtain microfibrillated cellulose.

[0021] Patent BR 102017001774-5, entitled “Process for obtaining cellulose nanofibers, less environmentally aggressive, and products obtained through the process”, owned by SOUZA SF, filed on January 27, 2017, describes the process for obtaining cellulose nanofibers from different vegetable fibers, which basically consists of grinding the natural fibers, followed by a hydrolysis process with a solution of sodium hydroxide and hydrogen peroxide under heating, which allows the removal of components such as lignin, hemicelluloses, extractives and all other components present in the fibers.

[0022] Patent ES2720950, entitled “Novel method for producing microcellulose”, owned by DAHL O., filed on July 25, 2019, describes a procedure for producing microcellulose comprising subjecting fibrous cellulosic material to acid hydrolysis at a temperature of at least 140 °C and with a consistency of 15 to 50% by dry weight of cellulose, wherein the amount of acid added is from 0.2 to 2% by dry weight of cellulose, and wherein the hydrolysis is carried out in a reactor without essential compression, the compression ratio of the reactor being less than 1.2:1. Petition 870250000472, dated 03 / 01 / 2025, page 14 / 30 9 / 14

[0023] Patent ES2708991, entitled “A novel method for producing microcellulose”, owned by DAHL O., filed on April 12, 2019, describes a process for producing microcellulose, characterized in that it comprises: i) hydrolysis of fibrous cellulosic material with an acid at an elevated temperature of at least 80°C, wherein the amount of acid is from 0.2 to 10% by dry weight of the cellulose, or ii) acidification of fibrous cellulosic material to a pH value of 4 or less than 4, followed by washing and hydrolysis of the washed cellulosic material at an elevated temperature of at least 80°C with an acid in an amount of no more than 0.5% by dry weight of the cellulose, to produce a microcellulose-hydrolysate mixture followed by separation of the microcellulose from the hydrolysate, wherein the mixture or the separated hydrolysate or microcellulose are optionally neutralized,and wherein the production of microcellulose is integrated into the production of a pulp mill such that at least some of the chemicals used in acidification, acid hydrolysis and / or neutralization are produced through an integrated chemical recovery process of the pulp mill.

[0024] Therefore, the present invention emerges as a viable process alternative, justifying the performance of the studies, as it will make available on the market a biopolymer that has been in demand by various sectors, such as the packaging industry, membranes, hydrogels and composite materials from various areas.

[0025] The objective of the invention is to develop a process for obtaining microfibrillated cellulose from a combined method, which uses ball milling, sulfuric acid, ethanol, sodium hydroxide and hydrogen peroxide. The process consists of utilizing biomass waste, which would possibly be underutilized or discarded, to extract microfibrillated cellulose with technological potential for use in the packaging, membrane, hydrogel and composite materials industries in various areas, contributing to technological development and reducing environmental impacts through reuse. Petition 870250000472, dated 03 / 01 / 2025, page 15 / 30 10 / 14

[0026] One of the objectives of the present invention is to define the process for obtaining microcellulose from vegetable waste such as pineapple peel, corn straw and cowpea pod husk, comprising the following steps: a) Cleaning the husks and straw with running water and soap; b) Rinsing of husks and straw; c) Drying of husks and straw in a kiln with air circulation; d) Grinding of husks and straw; e) Acid hydrolysis with sulfuric acid and ethanol; f) Bleaching with sodium hydroxide and hydrogen peroxide; g) Ball milling with acid hydrolysis using sulfuric acid. h) It is a further object of the present invention to perform the characterization of microfibrillated cellulose by means of Fourier Transform Infrared Spectroscopy (FTIR) analysis, thermogravimetric analysis (TGA / DTG), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).

[0027] These and other objects of the present invention are better understood and appreciated from the detailed description of the invention and its examples, which are intended only to illustrate one of the numerous ways of carrying out the invention, and therefore do not limit its scope.

[0028] Preliminary to the present description in order to obtain a better understanding of the characteristics of the present invention application, a set of figures and tables are attached hereto, as described below:

[0029] Figure 1 - shows the flowchart for obtaining microfibrillated cellulose.

[0030] Figure 2 - shows the spectra obtained by Fourier transform infrared spectroscopy (FTIR) analysis.

[0031] Figure 3 - shows the spectra of the TGA and DTG thermogravimetric analyses. Petition 870250000472, dated 03 / 01 / 2025, page 16 / 30 11 / 14

[0032] Figure 4 - presents Table 1 with the results of the Crystallinity Indices.

[0033] Figure 5 - shows micrographs of microfibrillated celluloses by scanning electron microscopy.

[0034] The present invention relates to the process of obtaining and characterizing microcellulose from plant waste, where the development addressed the following steps: a) Definition of the process for obtaining microcelluloses; b) Characterization of microcelluloses.

[0035] Figure 1 represents the flowchart of the process for obtaining microcelluloses from vegetable waste such as pineapple peel, corn straw, and cowpea pod husk. The process begins with obtaining raw material from its collection.

[0036] In the initial stage of the process, the waste underwent sanitization and drying. The vegetables were cleaned with detergent and running water, and selected according to the physical integrity of the peels and husks. The pineapple peels were removed with the aid of a knife. The husks of the cowpea pods were removed manually, separating the husk from the grains. The corn husks were obtained by manually separating the husks from the corn cob.

[0037] The husks and straw were spread on a metal tray forming a thin layer and dried in a forced-air oven at 50 °C until a constant mass was obtained.

[0038] After drying, the samples were ground in a household blender to reduce particle size and obtain flour from the husks and straw. At the end of the process, they were vacuum-packed, protected from light and Petition 870250000472, dated 03 / 01 / 2025, page 17 / 30 12 / 14 stored in a refrigerator at 4 °C, where they remained until subsequent steps.

[0039] The flour from the husks and straw underwent a delignification process, where a total of 20 g of each sample was separately delignified using 200 mL (1:1) of ethanol / distilled water (50 / 50%, v / v). The mixture remained under magnetic stirring for 2 h at boiling temperature (100 - -120 °C). After this period, the solution was filtered using a vacuum pump. The process was performed twice to ensure the elimination of waxes.

[0040] The husks and straws resulting from filtration were added to 200 mL of a 5% (v / v) aqueous sulfuric acid solution. The acid hydrolysis process occurred under constant stirring at 60 °C for 2 hours. After this period, it was washed with ethanol / water (1:1, v / v), vacuum filtered, and the process repeated 4 times for partial removal of lignin and hemicellulose. Finally, it was washed with distilled water until a neutral pH was reached. The husks and straws were placed to dry in a forced-air oven at 60 °C until a constant mass was obtained.

[0041] The flour from the husks and straw, obtained after the delignification step, is bleached with 24% (v / v) hydrogen peroxide and 4% (m / v) sodium hydroxide in aqueous solution, both in a 1:10 (g / mL) ratio. The reaction takes place under mechanical stirring at room temperature (25 °C) for 2 hours. The reaction is filtered using a vacuum pump and washed with distilled water until a neutral pH is reached. The resulting cellulose is dried in a forced-air oven at 60 °C until a constant mass is obtained.

[0042] Microfibrillated cellulose is prepared using ball milling and acid hydrolysis. In a polyethylene container (200 mL), a total of 3 g of cellulose and 90 mL of 30% aqueous sulfuric acid solution and 150 g of 3 mm diameter zirconia balls (50:1, m / m) are placed. Milling is carried out for 15 h. The milled product is filtered to remove the acid and washed with water. Petition 870250000472, dated 03 / 01 / 2025, page 18 / 30 13 / 14 distilled until neutral pH is obtained. The microfibrillated cellulose is dried in a forced-air oven at 60 °C until constant mass and stored under refrigeration (4 °C) until characterization analyses.

[0043] Figure 2 shows the infrared (FTIR) spectra of the raw residues, after acid hydrolysis treatments, bleaching and obtaining microfibrillated cellulose. The biomass spectra show that the process of obtaining microfibrillated cellulose causes the disappearance of absorption bands characteristic of the presence of lignin and hemicellulose at 1720, 1600, 1250 and 830 cm-1.

[0044] Figure 3 shows the TGA / DTG spectra of the raw residues, after acid hydrolysis treatments, bleaching, and obtaining microfibrillated cellulose. The spectra show that after the extraction process, the microcelluloses exhibit mass loss peaks below 100 °C, mainly attributed to water evaporation. The microcellulose spectra demonstrated maximum degradation temperatures ranging from 200-345 °C, depending on the biomass treated.

[0045] Figure 4 shows the crystallinity indices, calculated from X-ray Diffraction (XRD) analyses, of the raw residues, after acid hydrolysis treatments, bleaching, and obtaining microfibrillated cellulose. The extraction process positively influenced the increase in crystallinity, as a result of the removal of amorphous components (lignin) and non-crystalline polysaccharides such as hemicellulose. The increase in crystallinity promotes an increase in cellulose stiffness, which is associated with greater tensile strength (AYSE, A. and MOHINI, S. Biocomposites from wheat straw nanofibers: Morphology, thermal and mechanical properties. Composites Science and Technology, Toronto, v. 68, n. 2, p. 557-565, Feb. 2008). The crystallinities obtained for the microfibers of pineapple peel, cowpea pod husk, and corn straw were 73.39%, 69.23%, and 75.00%, respectively. Petition 870250000472, dated 03 / 01 / 2025, page 19 / 30 14 / 14

[0046] Figure 5 shows scanning electron microscopy (SEM) micrographs of microfibrillated cellulose. The results show that the extraction process was able to generate microfibers with an average length of around 300 nm. Lengths of 100 nm or more characterize the material as being on a micro scale. Petition 870250000472, dated 03 / 01 / 2025, page 20 / 30

Claims

1 / 2 CLAIMS 1. OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE RESIDUES THROUGH BALL MILLING AND ACID HYDROLYSIS ASSISTED, extracted from the peel of the pineapple (Ananas camosus), the husk of the cowpea pod (Vigna unguiculata) and corn straw (Zea mays L), characterized by comprising the following steps: a) Cleaning the peels and straws with running water and soap; b) Rinsing the peels and straws; c) Drying the peels and straws in an oven with air circulation; d) Grinding the peels and straws; e) Acid hydrolysis with sulfuric acid and ethanol; f) Bleaching with sodium hydroxide and hydrogen peroxide; g) Grinding in a ball mill with acid hydrolysis using sulfuric acid.

2. OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE RESIDUES THROUGH BALL MILLING AND ACID HYDROLYSIS ASSISTED, according to claim 1, characterized by using vegetable residues (peel of the pearl pineapple (Ananas camosus), the husk of the cowpea pod (Vigna unguiculata) and corn straw (Zea mays L)) as a source of raw material for obtaining microfibrillated cellulose.

3. OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE RESIDUES THROUGH BALL MILLING AND ASSISTED BY ACID HYDROLYSIS, according to claim 1, characterized by extracting through a chemical and mechanical method.

4. OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE RESIDUES THROUGH BALL MILLING AND ASSISTED BY ACID HYDROLYSIS, according to claims 1 and 3, characterized by Petition 870250000472, dated 03 / 01 / 2025, page 21 / 30 2 / 2 extracting through a chemical method using ethanol, sulfuric acid, sodium hydroxide and hydrogen peroxide.

5. OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE RESIDUES THROUGH BALL MILLING AND ASSISTED BY ACID HYDROLYSIS, according to claims 1 and 3, characterized by extracting through a mechanical method using ball milling with the aid of acid hydrolysis.

6. OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE RESIDUES THROUGH BALL MILLING AND ACID HYDROLYSIS ASSISTED, according to claims 1 to 3, characterized by presenting high crystallinity, good thermal stability and efficient insulation of the microcellulose, possessing potential application in the food, medicinal, civil and agricultural industries.

7. OBTAINING MICROFIBRILATED CELLULOSE FROM VEGETABLE WASTE THROUGH BALL MILLING AND ACID HYDROLYSIS ASSISTED, according to claims 1 to 3, characterized by presenting an environmentally suitable and economically viable alternative for industry, utilizing organic vegetable waste. Petition 870250000472, dated 03 / 01 / 2025, pp. 22 / 30

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