Aqueous Compositions and Method of Delignification of Plant Material

Abstract

AQUEOUS COMPOSITIONS AND METHOD FOR DELIGNIFICATION OF PLANT MATERIAL. An aqueous composition comprising: sulfuric acid; a compound comprising an amine fraction; a compound comprising a sulfonic acid fraction; and a peroxide. Said composition being capable of delignifying biomass.

Description

1 / 18 Aqueous Compositions and Method of Delignification of Plant Material FIELD OF THE INVENTION

[001] The present invention is directed to a method and composition useful in the decomposition of organic material, such as biomass, by oxidation, such as, but not limited to, biomass delignification, as a broad example, and more specifically, to a method and composition for performing it under more ideal conditions than those under which the kraft process is currently conducted. BACKGROUND OF THE INVENTION

[002] The first and most energy-intensive step in papermaking is pulp production. Besides water, wood and other plant materials used to make pulp contain three main components: cellulose fibers; lignin; and hemicelluloses. Pulping aims primarily to separate the fibers from the lignin. Lignin is a three-dimensional polymer that figuratively acts as a mortar to hold all the fibers together within the plant. Its presence in the finished pulp is undesirable and adds nothing to the finished product. Wood pulping refers to the breakdown of the bulk structure of the fiber source, whether chips, stems, or other plant parts, into constituent fibers. Cellulose fibers are the most desirable component involved in papermaking. Hemicellulose is a shorter branched carbohydrate polymer consisting of several sugar monomers that form a random amorphous polymeric structure.The presence of hemicellulose in the finished pulp is not as critical to the paper's stiffness as cellulose is. This is also true for biomass conversion. The challenges are similar. Only the desired outcome is different. Biomass conversion would have the additional breakdown into monocarbohydrates as a desired outcome, whereas... Petition 870220073623, dated 08 / 16 / 2022, pp. 85 / 107 2 / 18 a pulp and paper process typically stops shortly after the lignin dissolves.

[003] There are two main approaches to preparing wood pulp or woody biomass: mechanical treatment and chemical treatment. Mechanical treatment or pulping generally consists of physically separating wood chips and thus separating the cellulose fibers in an effort to separate them from each other. The shortcomings of this approach include: broken or damaged cellulose fibers, thus shorter fibers; and lignin contamination or residue in the cellulose fibers, thus introducing or leaving behind impurities in the final product. This process also consumes large amounts of energy and is capital intensive due to the high pressure, corrosive chemicals, and heat required. There are several approaches or processes included in chemical pulping. These are generally focused on the degradation of lignin and hemicellulose into water-soluble molecules.These now-degraded components are separated from the cellulose fibers by washing them without damaging the cellulose fibers. The chemical process is currently energy-intensive, as it typically requires high amounts of heat; and, in many cases, also necessitates agitation or mechanical intervention, adding inefficiencies and costs to the process.

[004] There are pulping or treatment methods that combine, to varying degrees, the chemical aspects of pulping with the mechanical aspects of pulping. To name a few, one should consider including thermomechanical pulping (also commonly called TMP) and chemothermomechanical pulping (CTMP). By selecting the advantages provided by each general pulping method, treatments are designed to reduce the amount of energy required by the mechanical aspect of pulping treatment. This can also directly affect the strength or Petition 870220073623, dated 08 / 16 / 2022, pp. 86 / 107 3 / 18 The degradation of the tensile strength of fibers subjected to these combined pulping approaches. Generally, these approaches involve a shorter chemical treatment (compared to conventional chemical pulping alone) which is then typically followed by a mechanical treatment to separate the fibers.

[005] The most common process for making pulp for paper production is the kraft process. In the kraft process, wood chips are converted into wood pulp, which is almost entirely pure cellulose fiber. The multi-stage kraft process consists of a first stage where the wood chips are impregnated / treated with a chemical solution. This is done by soaking the wood chips and then preheating them with steam. This stage swells the wood chips and expels the air present in them and replaces the air with liquid. This produces black liquor, a byproduct of the kraft process. It contains water, lignin residues, hemicellulose, and inorganic chemicals. Black liquor is a strong alkaline solution comprising sodium hydroxide and sodium sulfide. Once the wood chips have been soaked in the various chemical solutions, they undergo cooking.To achieve delignification of the wood chips, cooking is carried out for several hours at temperatures reaching up to 176 °C. At these temperatures, the lignin degrades to yield water-soluble fragments. The remaining cellulosic fibers are collected and washed after the cooking stage.

[006] U.S. Patent No. 5,080,756 teaches an improved kraft pulping process and is characterized by the addition of a composition of spent concentrated sulfuric acid containing organic matter to a kraft recovery system to provide a mixture enriched in its total sulfur content which is subjected to dehydration, pyrolysis and reduction in a recovery furnace. The organic matter in the sulfuric acid composition is Petition 870220073623, dated 08 / 16 / 2022, pp. 87 / 107 4 / 18 is particularly beneficial as a source of thermal energy, allowing high heat levels to be easily maintained to facilitate the oxidation and reduction reactions that occur in the furnace, thus resulting in the formation of sulfide used for the preparation of cooking liquor suitable for pulping.

[007] Caro's acid, also known as peroxymonosulfuric acid (H2SO5), is one of the strongest oxidizers known. There are several known reactions for the preparation of Caro's acid, but one of the most straightforward involves the reaction between sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). The preparation of Caro's acid in this method allows for a further reaction yield of potassium monopersulfate (PMPS), which is a valuable bleaching and oxidizing agent. Although Caro's acid has several known useful applications, its use in wood delignification is noteworthy.

[008] Biofuel production is another potential application for the kraft process. One of the current disadvantages of biofuel production is that it requires the use of food-grade plant parts (such as seeds) in order to transform carbohydrates into fuel in a reasonably efficient process. Carbohydrates can be obtained from cellulosic fibers by using non-food-grade biomass in the kraft process; however, the energy-intensive nature of the kraft process for delignification makes this option less commercially viable. In order to build a plant-based chemical resource cycle, there is a great need for energy-efficient processes that can utilize plant-based inputs that do not compete with human food production.

[009] While the kraft pulping process is the most widely used chemical pulping process in the world, it is extremely energy-intensive and has other disadvantages, for example, substantial odors emitted around the pulp production plants or general emissions that are now being Petition 870220073623, dated 08 / 16 / 2022, pp. 88 / 107 5 / 18 highly regulated in many pulp and paper production jurisdictions. In light of current environmental challenges, economic challenges, and climate change, along with the emission rates being implemented, it is highly desirable to optimize current pulping processes in order to provide at least linear quality fibers without the current substantial detriment to the environment during their production. Consequently, there is still a need for a composition capable of performing delignification in wood material under reduced temperatures and pressures versus what is currently in use without requiring any additional capital expenditure. SUMMARY OF THE INVENTION

[010] According to one aspect of the present invention, an aqueous acidic composition is provided comprising: - sulfuric acid; - a compound comprising an amine moiety; - a compound comprising a sulfonic acid fraction; and - a peroxide.

[011] According to one aspect of the present invention, an aqueous acidic composition is provided comprising: - sulfuric acid; - a compound comprising an amine moiety; - a compound comprising a sulfonic acid fraction; wherein the sulfuric acid and said compound comprising an amine fraction and said compound comprising a sulfonic acid fraction are present in a molar ratio of not less than 1:1:1.

[012] Preferably, sulfuric acid and said compound comprising an amine moiety and said compound comprising a sulfonic acid moiety are present in a molar ratio ranging from Petition 870220073623, dated 08 / 16 / 2022, pp. 89 / 107 6 / 18 28:1:1 to 2:1:1. More preferably, sulfuric acid and said compound comprising an amine fraction and said compound comprising a sulfonic acid fraction are present in a molar ratio ranging from 24:1:1 to 3:1:1. Preferably, sulfuric acid and said compound comprising an amine fraction and said compound comprising a sulfonic acid fraction are present in a molar ratio ranging from 20:1:1 to 4:1:1. More preferably, sulfuric acid and said compound comprising an amine fraction and said compound comprising a sulfonic acid fraction are present in a molar ratio ranging from 16:1:1 to 5:1:1. According to a preferred embodiment of the present invention, sulfuric acid and said compound comprising an amine fraction and said compound comprising a sulfonic acid fraction are present in a molar ratio ranging from 12:1:1 to 6:1:1.

[013] According to a preferred embodiment of the present invention, said compound comprising an amine moiety and said compound comprising a sulfonic acid moiety are present in a molar ratio ranging from 2:1 to 1:2.

[014] According to another preferred embodiment of the present invention, said compound comprising an amine moiety and said compound comprising a sulfonic acid moiety are present in a molar ratio ranging from 3:1 to 1:3.

[015] According to a preferred embodiment of the present invention, said compound comprising an amine moiety and said compound comprising a sulfonic acid moiety are present in a molar ratio ranging from 4:1 to 1:4.

[016] According to a preferred embodiment of the present invention, said compound comprising an amine moiety and said compound Petition 870220073623, dated 08 / 16 / 2022, pp. 90 / 107 7 / 18 comprising a fraction of sulfonic acid are present in a molar ratio ranging from 5:1 to 1:5.

[017] Also preferably, said compound comprising an amine moiety has a molecular weight below 300 g / mol. Also preferably, said compound comprising an amine moiety has a molecular weight below 150 g / mol. More preferably, said compound comprising an amine moiety is a primary amine. Even more preferably, said compound comprising an amine moiety is an alkanolamine. Even more preferably, said compound comprising an amine moiety is a tertiary amine.

[018] According to a preferred embodiment of the present invention, the alkanolamine is selected from the group consisting of: monoethanolamine; diethanolamine; triethanolamine; and combinations thereof. Preferably, the alkanolamine is triethanolamine.

[019] According to a preferred embodiment of the present invention, the compound comprising a sulfonic acid fraction is selected from the group consisting of: alkylsulfonic acids in which the alkyl groups range from C1-C6 and are linear or branched; and combinations thereof. Preferably, said compound comprising a sulfonic acid fraction is selected from the group consisting of: methanesulfonic acid; ethanesulfonic acid; propanesulfonic acid; 2-propanesulfonic acid; isobutylsulfonic acid; t-butylsulfonic acid; butanesulfonic acid; isopentylsulfonic acid; t-pentylsulfonic acid; pentanesulfonic acid; t-butylhexanesulfonic acid; and combinations thereof. More preferably, said compound comprising a sulfonic acid fraction is methanesulfonic acid.

[020] According to one aspect of the present invention, a Petition 870220073623, dated 08 / 16 / 2022, pp. 91 / 107 8 / 18 aqueous composition for use in the delignification of biomass, such as wood, wherein said composition comprises: - sulfuric acid; - a compound comprising an amine moiety; - a compound comprising a sulfonic acid fraction; and - a peroxide. wherein sulfuric acid, the compound comprising an amine moiety, and the compound comprising a sulfonic acid moiety are present in a molar ratio ranging from 2:1:1 to 30:1:1.

[021] According to one aspect of the present invention, an aqueous composition is provided for use in breaking down cellulose from biomass (i.e., a plant source), wherein said composition comprises: - sulfuric acid at 20 to 70% by weight of the total weight of the composition; - a compound comprising an amine moiety; - a compound comprising a sulfonic acid fraction; and - a peroxide; wherein sulfuric acid, the compound comprising an amine moiety, and the compound comprising a sulfonic acid moiety are present in a molar ratio ranging from 2:1:1 to 30:1:1.

[022] Preferably, the peroxide is hydrogen peroxide.

[023] According to one aspect of the present invention, a method for delignifying biomass / plant material is provided, said method comprising: - to provide the aforementioned plant material comprising cellulose and lignin fibers; - to expose the aforementioned plant material which requires a composition comprising: Petition 870220073623, dated 08 / 16 / 2022, pp. 92 / 107 9 / 18 sulfuric acid in 20 to 70% by weight of the total weight of the composition; a compound comprising an amine moiety; a compound comprising a sulfonic acid fraction; for a period of time sufficient to substantially remove all lignin present in the said plant material. Preferably, the composition also includes a peroxide.

[024] Preferably, the compound comprising a sulfonic acid fraction is selected from the group consisting of: alkylsulfonic acids in which the alkyl groups range from C1-C6 and are linear or branched; and combinations thereof. Preferably, said compound comprising a sulfonic acid fraction is selected from the group consisting of: methanesulfonic acid; ethanesulfonic acid; propanesulfonic acid; 2-propanesulfonic acid; isobutylsulfonic acid; t-butylsulfonic acid; butanesulfonic acid; isopentylsulfonic acid; t-pentylsulfonic acid; pentanesulfonic acid; t-butylhexanesulfonic acid; and combinations thereof. More preferably, said compound comprising a sulfonic acid fraction is methanesulfonic acid.

[025] Preferably, said compound comprising an amine moiety has a molecular weight below 300 g / mol. More preferably, said compound comprising an amine moiety has a molecular weight below 150 g / mol. According to a preferred embodiment of the present invention, the composition has a pH less than 1. According to another preferred embodiment of the present invention, the composition has a pH less than 0.5.

[026] The inventors discovered that delignification of biomass, such as wood / wood pulp material (for example, but not limited to wood chips), can occur at substantially lower temperatures. Petition 870220073623, dated 08 / 16 / 2022, pp. 93-107 10 / 18 of those used during the conventional kraft pulping process. In fact, experiments conducted at room temperature with preferred compositions according to the present invention showed that they degrade the lignin present in wood chips to release cellulose fibers. According to a preferred embodiment of a method according to the present invention, a wood sample was dissolved at 30 °C by exposure to a composition according to a preferred embodiment of the present invention. According to a preferred embodiment of the present invention, the energy input costs involved in the delignification of current pulp can be substantially reduced by applying a method involving a preferred composition of the present invention. BRIEF DESCRIPTION OF THE FIGURES

[027] The invention can be more fully understood by considering the following description of various embodiments of the invention in connection with the accompanying figures, in which: Figure 1 is a photograph of the dissolution of a wood chip in a composition according to the present invention where the elapsed time was 1 minute; and Figure 2 is a photograph of the dissolution of a wood chip in a composition according to the present invention, where the elapsed time was 24 hours. DESCRIPTION OF THE INVENTION

[028] Experiments conducted using an aqueous acidic composition according to a preferred embodiment of the present invention showed that wood chips can undergo delignification under controlled reaction conditions and eliminate or at least minimize cellulose degradation. By degradation is meant cellulose darkening or carbonization (conversion). Petition 870220073623, dated 08 / 16 / 2022, pp. 94 / 107 11 / 18 in carbon black) which symbolizes an uncontrolled acid attack on cellulose and its discoloration.

[029] Preferably, the compound comprising an amine moiety and the compound comprising a sulfonic acid moiety are present in a 1:1 ratio. Together in the presence of sulfuric acid, there appears to be a coordination of the compounds that acts as a modified sulfuric acid. In this respect, the presence of a sulfonic acid group together with an amine group is believed to be part of this modified acid. The resistance of the modified acid is dictated by the moles of sulfuric acid to the moles of the compound comprising an amine moiety and the compound comprising a sulfonic acid moiety. Thus, a composition comprising a molar ratio of 6:1:1 of sulfuric acid: the compound comprising an amine moiety: the compound comprising a sulfonic acid moiety would be much less reactive than a composition of the same components in a molar ratio of 28:1:1.It was also noted that the ratio between the compound comprising an amine fraction and the compound comprising a sulfonic acid fraction can vary from 0.5:1 to 2:1 without having a perceptible impact on the reactivity of the entire composition, i.e., when placed in the presence of sulfuric acid.

[030] By delignifying wood using a composition according to a preferred embodiment of the present invention, the process can be carried out at substantially lower temperatures than those used in the conventional kraft pulping process. The advantages are substantial; here are some: the kraft pulping process requires temperatures close to 176 to 180 °C to carry out the delignification process; a preferred embodiment of the process according to the present invention can delignify wood at much lower temperatures. Petition 870220073623, dated 08 / 16 / 2022, pp. 95 / 107 12 / 18 low, even as low as 20 °C. According to a preferred embodiment of the present invention, wood delignification can be carried out at temperatures as low as 0 °C. According to a preferred embodiment of the present invention, wood delignification can be carried out at temperatures as low as 10 °C. According to a preferred embodiment of the present invention, wood delignification can be carried out at temperatures as low as 30 °C. According to another preferred embodiment of the present invention, wood delignification can be carried out at temperatures as low as 40 °C. According to yet another preferred embodiment of the present invention, wood delignification can be carried out at temperatures as low as 50 °C. According to yet another preferred embodiment of the present invention, wood delignification can be carried out at temperatures as low as 60 °C.Other advantages include: lower energy input; reduced emissions and reduced capital expenditure; reduced maintenance; lower shutdown / return-on costs; there are also HSE advantages compared to conventional kraft pulping compositions.

[031] In each of the above preferred embodiments, the temperature at which the processes are carried out is substantially lower than the current energy-intensive kraft process.

[032] Furthermore, the kraft process uses high pressures to perform wood delignification, which is initially capital-intensive, hazardous, expensive to maintain, and has high associated turnaround costs. According to a preferred embodiment of the present invention, wood delignification can be performed at atmospheric pressure. This, in turn, circumvents the need for highly specialized and expensive industrial equipment, such as pressure vessels / digesters. It also allows for the deployment of units Petition 870220073623, dated 08 / 16 / 2022, pp. 96 / 107 13 / 18 delignification in many parts of the world where the implementation of a kraft plant would previously have been unfeasible for various reasons.

[033] Some of the advantages of a process according to a preferred embodiment of the present invention compared to a conventional kraft process are substantial, since the heat / energy requirement for the latter is not only a major source of pollution, but is largely the reason why the resulting pulp product is so expensive and has high initial capital requirements. The energy savings in implementing a process according to a preferred embodiment of the present invention would be reflected in a lower-priced pulp and environmental benefits that would have both an immediate impact and a lasting multi-generational benefit for all.

[034] Still other cost savings in the full or partial implementation of a process according to a preferred embodiment of the present invention can be found in the absence or minimization of restrictive regulations for the operation of high temperature and high pressure pulp digesters. Experiment #1

[035] A preferred embodiment of the composition according to the present invention was tested to determine its ability to delignify a wood chip.

[036] The experiments were completed using approximately 0.2 g of wood and approximately 20 g of solution. The mixtures were stirred at 200 rpm at a temperature of 30 °C.

[037] Figures 1 and 2 show the dissolution of two wood chips in the presence of a composition according to a preferred embodiment of the present invention. The composition according to the preferred embodiment in Petition 870220073623, dated 08 / 16 / 2022, pp. 97 / 107 Question 14 / 18 comprises sulfuric acid and monoethanolamine and methanesulfonic acid in a 6:1:1 ratio. It is worth noting that the solution is still clear after 1 minute (see Figure 1). A sulfuric acid composition would have already shown signs of discoloration, indicative of cellulose degradation into carbon black. In fact, the solution remains clear throughout the experiment, which lasted up to 24 hours (see Figure 2). After 24 hours, the solution managed to dissolve all the lignin present in the wood chips, keeping the crystalline cellulose packets intact (or substantially intact). This is evidence of a mild oxidizing composition that specifically targets lignin while sparing cellulose.

[038] The above experiment is a clear indication that a preferred composition according to the present invention not only provides a suitable dissolving acid for delignifying plant material, but is also valuable in controlling the final degradation of cellulosic material into carbon black residue, resulting in potentially higher yields for operators, thereby increasing profitability and reducing emissions and risk to employees, contractors and the public. Additional delignification experiments

[039] Sulfuric acid, methanesulfonic acid (MSA), triethanolamine (TEOA), and hydrogen peroxide were mixed with increasing concentrations of MSA and TEOA and reacted with biomass (wood chips) overnight under ambient conditions to evaluate the effectiveness of varying molar ratios on the extent of reaction. Control tests were performed for the respective mixtures with only kraft lignin or only cellulose added instead of biomass. Commercially available lignin (Sigma-Aldrich; Lignin, kraft; Prod No. 471003) was used as a control in the test. Commercially available cellulose (Sigma-Aldrich; Cellulose, fibers (medium); Prod No. Petition 870220073623, dated 08 / 16 / 2022, pp. 98 / 107 15 / 18 C6288 was also used as a control in the tests.

[040] The solid phase of each mixture was filtered after 20 hours of reaction, rinsed with water, and dried in an oven at 45 °C until constant weight. An effective mixture should dissolve all the lignin and leave the cellulose as intact as possible. The results of the experiments are reported in Table 1 below. Table 1 - Solids recovery (% of initial mass) after 20h reaction time Wood Mixture (% by weight remaining after reaction) Control Lignin (% by weight remaining after reaction) Control Cellulose (% by weight remaining after reaction) 28:1:1:28 43.21 0.00 43.21 10:1:1:10 47.13 0.00 88.63 2:1:1:2 54.65 21.74 91.92

[041] A mixture with a ratio of 28:1:1:28 of sulfuric acid (96% concentration used) to MSA to TEOA to hydrogen peroxide (as a 30% solution) results in a mass recovery of 43% of wood and cellulose. This shows that the acid / peroxide mixture is too aggressive and depolymerizes the cellulose too much. No lignin could be recovered, which is the required result. When the concentration of the MSA / TEOA retarding mixture is increased to one-tenth of the acid and peroxide concentration, still all the lignin is depolymerized enough to go into solution. However, the cellulose is no longer as attacked. 89% of the cellulose can be recovered with this mixture. Increasing the retarding concentration to half the acid / peroxide concentration slows the digestion of the biomass to a level that is much less desirable. 55% of the wood mass and 92% of the cellulose could be recovered, but 22% of the lignin was not put into solution. Petition 870220073623, dated 08 / 16 / 2022, pp. 99 / 107 16 / 18 Batch process using a mixture of H2SO4: TEOA: MSA: H2O2 in a molar ratio of 10:1:1:10

[042] A batch process was carried out in order to scale up the compositions and process discussed previously. For the preparation of a batch process, 3.409 g of sulfuric acid (93%) were placed in a large glass reactor (10 L) and 444 g of methanesulfonic acid (70%) and 482 g of triethanolamine were added. The mixture was stirred at 100 RPM. Then, 3.665 g of hydrogen peroxide solution (29%) were added slowly (over 1 to 1.5 hours) to the modified acid. The reactor was cooled to dissipate the generated heat so that the temperature of the mixture did not exceed 40 °C. After the addition of hydrogen peroxide, the reactor system was allowed to equilibrate at room temperature (30 minutes). The molar ratio of the mixture (in order of addition) was 10:1:10. 400 g of unmeasured wood shavings (sawdust) were slowly added to the reactor. The temperature increase was monitored.When the reactor temperature reached 55 °C, the reactor was cooled to a temperature of 26 °C. After that, further cooling was no longer necessary. The reaction was carried out for 20 h, then the reaction mixture was transferred to a filter system with a 20 μm Teflon filter sheet. The filtrate was discarded and the remaining filter cake washed with 12 L of water until the runoff reached a pH value of approximately 6. The filter cake was dried in an oven (45 °C) overnight. The cellulose yield compared to the added biomass was 43.2%.

[043] The hydrocarbon content of the resulting cellulose was determined to be 94.4%, which is close to the Sigma-Aldrich standard cellulose batch no. WXBC9745V - 95.7% used as a comparison. The water content was determined to be 1.70%, which is close to the Sigma-Aldrich standard cellulose batch no. WXBC9745V - 3% used as a comparison. The Kappa number = 0, which means that Petition 870220073623, dated 08 / 16 / 2022, pages 100 / 107 17 / 18 there is no more lignin in the sample. X-ray diffraction was performed on the sample and indicated that the apparent crystallinity was 58.2%, which is in accordance with our previously tested numbers, and commercial Aldrich cellulose was measured at 62.9%. Scanning electron microscopy shows a material with a very high fiber content.

[044] A method for producing glucose from wood pulp would represent a significant advance over the current process, where such conversion is chemical and energy-intensive, expensive, emission-intensive and hazardous, without resulting in highly efficient results, especially in large-scale operations. It is desirable to employ a composition that can delignify the wood but also allow the operator some control to preserve the cellulose instead of degrading it into carbon black, resulting in higher efficiencies and yields, along with greater safety and reduced overall costs.

[045] According to a preferred embodiment of the method of the present invention, the separation of lignin can be effective and the resulting cellulose fibers can be further processed to produce glucose monomers. Glucose chemistry has a myriad of uses, including as a starting block in the preparation of widely used chemicals, including, but not limited to, diacetonide, dithioacetal, glycoside, glucal and hydroxyglucal, to name just a few.

[046] According to another preferred embodiment of the present invention, the composition can be used to decompose organic material by oxidation, such as those used in water treatment, water purification and / or water desalination. An example of this is the removal (i.e., destruction) of algae in filtration membranes. As such membranes can be considerably expensive, it is imperative that they be used for the longest possible time. Petition 870220073623, dated 08 / 16 / 2022, pages 101 / 107 18 / 18 possible. However, given the difficulty of removing the organic matter that accumulates on it over time, new approaches are needed to do this efficiently and with the least possible damage to the membrane. Mineral acids are too strong and, while removing organic matter, damage filtration membranes. A preferred composition of the present invention remedies this problem, since it is less aggressive than mineral acids and, as such, removes organic contaminants in a much gentler way, thus sparing the membrane.

[047] Although the preceding invention has been described in some detail for the sake of clarity and understanding, it will be appreciated by those skilled in the art, once they are familiar with this invention, that various changes in form and details can be made without departing from the true scope of the invention in the appended claims. Petition 870220073623, dated 08 / 16 / 2022, pp. 102 / 107

Claims

1 / 3 CLAIMS 1. An aqueous acidic composition, characterized in that it consists of: - sulfuric acid; - a compound comprising an amine moiety, selected from the group consisting of: alkanolamines; - a compound comprising a sulfonic acid moiety, selected from the group consisting of: alkylsulfonic acids, wherein the alkyl groups range from C1-C6 and are linear or branched; and - a peroxide; wherein the sulfuric acid and the said compound comprising an amine moiety are present in a molar ratio of not less than 1:1; and wherein the pH of the composition is less than 1.

2. Composition according to claim 1, characterized in that sulfuric acid and said compound comprising an amine moiety are present in a molar ratio ranging from 28:1 to 2:

1.

3. Composition according to claim 1 or 2, characterized in that said compound comprising an amine moiety is a primary amine.

4. Composition according to claim 1 or 2, characterized in that said compound comprising an amine moiety is a tertiary amine.

5. Composition according to claim 1, characterized in that said alkanolamine is selected from the group consisting of: monoethanolamine; diethanolamine; triethanolamine; and combinations thereof.

6. Composition according to claim 5, characterized by the fact that the said alkanolamine is triethanolamine.

7. Composition according to claim 1, characterized in that said alkylsulfonic acid is selected from the group consisting of: methanesulfonic acid; ethanesulfonic acid; propanesulfonic acid; 2-propanesulfonic acid; isobutylsulfonic acid; t-butylsulfonic acid; butanesulfonic acid; isopentylsulfonic acid; t-pentylsulfonic acid; pentanesulfonic acid; t-butylhexanesulfonic acid; and combinations thereof.

8. Composition according to any one of claims 1 to 7, characterized in that said compound comprising a sulfonic acid fraction is methanesulfonic acid.

9. Composition according to any one of claims 1 to 8, characterized in that the peroxide is hydrogen peroxide.

10. Aqueous composition for use in wood delignification, characterized in that said composition comprises an aqueous acidic composition defined in claim 1; wherein sulfuric acid and the compound comprising an amine fraction are present in a molar ratio ranging from 2:1 to 28:

1.

11. Aqueous composition for use in the processing and depolymerization of cellulose from a vegetable source, characterized in that said composition comprises an aqueous acidic composition defined in claim 1; wherein the sulfuric acid is in 20 to 70% by weight of the total weight of the composition; and wherein the sulfuric acid and the compound comprising an amine fraction are present in a molar ratio ranging from 2:1 to 28:

1.

12. Method for delignifying plant material, characterized by Petition 870260054591, dated 05 / 06 / 2026, page 14 / 15 3 / 3, in that said method comprises: - providing said plant material comprising cellulose fibers and lignin; - exposing said plant material to an aqueous acidic composition defined in claim 1, wherein the sulfuric acid is at 20 to 70% by weight of the total weight of the composition; for a period of time sufficient to substantially remove all lignin present in said plant material.

13. Method according to claim 12, characterized in that said compound comprising a sulfonic acid fraction is selected from the group consisting of: methanesulfonic acid; ethanesulfonic acid; propanesulfonic acid; butanesulfonic acid; pentanesulfonic acid; hexanesulfonic acid; and combinations thereof. Petition 870260054591, dated 05 / 06 / 2026, page 15 / 15

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