Wildfire suppressant and forest damage restoration agent comprising eco-friendly biodegradable soil coagulant

Abstract

The present invention relates to a wildfire suppressant and a forest damage restoration agent comprising an eco-friendly biodegradable soil coagulant. The eco-friendly soil coagulant of the present invention comprises starch and nanocellulose, wherein the aldehyde group of the starch is bonded to the nanocellulose through acetal crosslinking such that the starch becomes non-toxic and biodegradable, with the ability to absorb a large amount of moisture, and thus can function as both a wildfire suppressant and a forest damage restoration agent.

Description

Forest fire spread prevention agent and forest damage restoration agent containing biodegradable, eco-friendly soil coagulant

[0001] This patent application claims priority to Republic of Korea Patent Application No. 10-2023-0107186, filed with the Korean Intellectual Property Office on August 16, 2023, the disclosure of which is incorporated herein by reference.

[0002] The present invention relates to a forest fire spread prevention agent and a forest damage restoration agent comprising a biodegradable, eco-friendly soil coagulant.

[0003] Topsoil, the soil that forms the geological surface, generally refers to the area up to 30cm below the surface. It is formed by the addition of various organic substances and ash, combined with inorganic materials derived from weathered rocks and other minerals. Compared to subsoil and rocky areas, where water and nutrient movement are difficult, topsoil directly and indirectly influences plant growth, mitigates climate change through carbon storage, and fosters microbial activity, playing a vital role in the environment and ecosystem.

[0004] South Korea is highly vulnerable to natural and artificial soil erosion due to rainfall characteristics and land use patterns resulting from climate change. According to the Ministry of Environment's 'National Topsoil Erosion Preliminary Survey (2012),' 30% of the country's land is experiencing soil erosion of 1 m per year. 2 It has been reported that over 3.3 kg of surface soil has been lost, and considering the current and future climate change, where heavy rainfall is becoming more frequent even with similar annual precipitation compared to that time, there are concerns that even greater amounts of topsoil may be lost.

[0005] In particular, due to the loss of topsoil, the environmental control functions of the topsoil, such as purifying pollutants and regulating air and water quality, are weakened, and when the lost topsoil flows into rivers, it causes water pollution such as riverbed expansion and eutrophication. In addition, topsoil is a finite resource that takes a very long time, more than 200 years, to form 1cm thick topsoil. In addition to the primary damage such as reduced plant growth caused by simple topsoil loss, the lost topsoil promotes eutrophication of rivers and lakes in tributaries and streams, which causes green algae blooms, resulting in negative impacts on the ecosystem.

[0006] To address this phenomenon, the United States is implementing preventative soil resource conservation policies under the Soil Conservation Act, while Germany's Federal Soil Conservation Act grants the executive branch the authority to impose fines and criminal penalties for violations of topsoil protections against destruction and loss. While many developed countries are making various efforts, including developing legislative measures, to protect topsoil, South Korea lacks a clear response, and its measures against topsoil loss remain rudimentary compared to those of developed countries.

[0007] There are preventive measures for topsoil loss, such as vegetation techniques and engineering techniques, depending on the degree of loss. However, these methods have the disadvantage of taking a long time to change land use from planning to implementation and incurring excessive costs.

[0008] The most effective way to prevent topsoil erosion in a short time and at a low cost without changing land use is to use soil flocculants. Currently, most soil flocculants are manufactured from chemical absorbents (super absorbent polymers, SAP). Super absorbent polymers absorb water and form hydrogels, and the resulting adsorption properties increase soil bonding, making it easy and economical to reduce soil erosion. However, SAP takes more than 500 years to biodegrade, and if soil flocculants are lost, they can become microplastics, causing ecosystem destruction and, in particular, posing a fatal threat to human health due to bioaccumulation. Furthermore, while polymeric absorbents are known to be non-toxic, there is controversy over the toxicity of their monomers when they decompose in the future, presenting many problems for the use of SAP as a soil flocculant.

[0009] Therefore, in order to prevent topsoil erosion, there is an urgent need to develop an environmentally friendly soil coagulant that has the moisture-retaining capacity of the SAP, is non-toxic, and can be naturally decomposed in the ecosystem.

[0010] Accordingly, in order to solve the above-mentioned technical problem, the inventors of the present invention have endeavored to create an eco-friendly soil coagulant containing nanocellulose that has a high moisture retention capacity, is non-toxic and biodegradable, and can absorb a large amount of moisture.

[0011] As a result, it was confirmed that the soil aggregate manufactured by adding natural polysaccharides such as starch to suspensions using various grades of nanocellulose made from various non-woody lignocellulose-based biomass such as banana pseudostem, sugarcane, and oil palm as well as traditional pulp from cotton and woody biomass, and heating, stirring, drying, and grinding to granulate, had remarkably excellent moisture retention capacity and biodegradability.

[0012] Accordingly, the present invention aims to provide a biodegradable, eco-friendly soil coagulant that is non-toxic and biodegradable and can absorb a large amount of moisture, thereby functioning as a forest fire spread prevention agent and a forest damage restoration agent.

[0013] In order to achieve the above purpose, it comprises starch and nanocellulose,

[0014] The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass,

[0015] The above nanocellulose has a viscosity of 3,000 to 500,000 cPs,

[0016] The above-mentioned aldehyde group of the starch is a polymer that is acetal crosslinked with the hydroxyl group of the nanocellulose, thereby providing an eco-friendly soil coagulant.

[0017] In addition, the present invention provides a method for producing an eco-friendly soil coagulant comprising the following steps:

[0018] (S10) A step of obtaining nanocellulose having a viscosity of 3,000 to 500,000 cPs from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass;

[0019] (S20) A step of preparing a hydrogel by mixing the nanocellulose of the above step (S10) with starch;

[0020] (S30) A step of drying the hydrogel of the step (S20) to obtain a dried hydrogel; and

[0021] (S40) A grinding step for grinding the result of the above step (S30) to obtain an eco-friendly soil coagulant.

[0022] In addition, the present invention includes starch and nanocellulose,

[0023] The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass,

[0024] The above nanocellulose has a viscosity of 3,000 to 500,000 cPs,

[0025] The present invention provides a forest fire spread prevention agent including an eco-friendly soil coagulant, which is a polymer in which the aldehyde group of the starch is acetal crosslinked with the hydroxyl group of the nanocellulose.

[0026] In addition, the present invention includes starch and nanocellulose,

[0027] The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass,

[0028] The above nanocellulose has a viscosity of 3,000 to 500,000 cPs,

[0029] The present invention provides a forest damage restoration agent including an eco-friendly soil coagulant, which is a polymer in which the aldehyde group of the starch is acetal crosslinked with the hydroxyl group of the nanocellulose.

[0030] The present invention relates to a forest fire prevention agent and a forest damage restoration agent, which comprises a biodegradable, eco-friendly soil coagulant that is a polymer comprising starch and nanocellulose, and in which an aldehyde group of the starch is acetal crosslinked with the nanocellulose. The soil coagulant of the present invention is non-toxic and biodegradable and can absorb a large amount of moisture, and thus can function as a forest fire prevention agent and a forest damage restoration agent.

[0031] Figure 1 is a schematic diagram showing the overall manufacturing process of a biodegradable, eco-friendly soil coagulant according to one manufacturing example of the present invention.

[0032] Figure 2 is a drawing showing a sample before biodegradability evaluation of a biodegradable, eco-friendly soil coagulant according to one manufacturing example of the present invention.

[0033] Figure 3 is a graph showing the moisture absorption amount over time of a biodegradable, eco-friendly soil coagulant according to one manufacturing example of the present invention, measured for 6 hours.

[0034] Figure 4 is a graph showing the moisture absorption amount over time of a biodegradable, eco-friendly soil coagulant according to one manufacturing example of the present invention, measured for 5 days.

[0035] Figure 5 is a graph showing the moisture absorption amount over time of a biodegradable, eco-friendly soil coagulant according to one manufacturing example of the present invention, measured for 28 days.

[0036] Figure 6 is a graph showing the moisture absorption amount over time of a biodegradable, eco-friendly soil coagulant according to one manufacturing example of the present invention, measured for 112 days.

[0037] Contains starch and nanocellulose,

[0038] The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass,

[0039] The above nanocellulose has a viscosity of 3,000 to 500,000 cPs,

[0040] An eco-friendly soil coagulant, wherein the aldehyde group of the starch is a polymer formed by acetal crosslinking with the hydroxyl group of the nanocellulose.

[0041] Hereinafter, the present invention will be described in more detail.

[0042] The present invention comprises starch and nanocellulose,

[0043] The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass,

[0044] The above nanocellulose has a viscosity of 3,000 to 500,000 cPs,

[0045] The present invention relates to an eco-friendly soil coagulant, wherein the aldehyde group of the starch is a polymer formed by acetal crosslinking with the hydroxyl group of the nanocellulose.

[0046] In the present invention, the soil coagulant is characterized in that it does not contain a separate chemical cross-linking agent or cross-linking agent.

[0047] In the present invention, the soil coagulant is manufactured through a solution process, and the aldehyde group of starch may react with the hydroxyl group of nanocellulose to form an acetal cross-linking polymer.

[0048] Starch is composed of amylose and amylopectin, each of which is a monosaccharide linked by a glycosidic bond. Through the glycosidic bonds of the starch, the soil coagulant forms a three-dimensional network structure through hydrogen bonds between natural polysaccharide chains, thereby trapping water within.

[0049] In the present invention, the starch may be at least one selected from the group consisting of root starch, cereal starch, and glutinous cereal starch, and may be, for example, root starch, but is not limited thereto.

[0050] In the present invention, the root starch may be at least one selected from the group consisting of potato, sweet potato, taro, and tapioca.

[0051] In the present invention, the cereal starch may be at least one selected from the group consisting of rice, wheat, barley, and corn, but is not limited thereto.

[0052] In the present invention, the glutinous grain starch may be at least one selected from the group consisting of glutinous rice, sorghum, millet, and glutinous corn, but is not limited thereto.

[0053] In one embodiment of the present invention, the starch may be tapioca.

[0054] In one embodiment of the present invention, the starch may be corn.

[0055] In one embodiment of the present invention, the starch may be tapioca and corn, and the weight ratio of the tapioca and the corn may be 4:1, 3:1, 2:1, 4:1, 3:1, 2:1, for example, 1:1, but is not limited thereto.

[0056] In the present invention, the term "oxidized starch" refers to a product obtained by oxidation of starch. Oxidized starch may be obtained in the form of dialdehyde starch by oxidizing starch with sodium hypochlorite and / or hydrogen peroxide. The aldehyde group is highly reactive and can react with various reactive groups. As the degree of oxidation of oxidized starch increases, aging phenomenon is reduced, viscosity stability is improved, and the degree of viscosity increase upon cooling is reduced.

[0057] In the present invention, the term 'aging' means that when starch is left to stand, hydrogen bonds are re-formed between some linear amylose molecular structures to form a crystalline structure.

[0058] In the present invention, nanocellulose refers to nanocellulose that can have various functional groups such as carboxymethyl groups, carboxyl groups, and amine groups, which have been verified for safety and efficacy. Nanocellulose is a raw material that is biodegradable and harmless to the human body, and can replace existing absorbable chemical products. Nanocellulose is a semi-synthetic hydrophilic cellulose derivative that introduces various functional groups such as carboxymethyl groups, carboxyl groups, and amine groups into the cellulose molecular unit, and has high viscosity and a molecular weight of 5,000 to 700,000 Da, and is in the form of granules or fibrous powder, and is white, yellowish, or grayish, slightly hygroscopic, odorless, and tasteless.

[0059] In the present invention, nanocellulose may be obtained from at least one selected from the group consisting of cotton, wood biomass, and non-wood biomass, but is not limited thereto.

[0060] In the present invention, the nanocellulose has a viscosity of 3,000 to 500,000 cPs, 3,000 to 400,000 cPs, 3,000 to 300,000 cPs, 3,000 to 200,000 cPs, 3,000 to 100,000 cPs, 3,000 to 50,000 cPs, 3,000 to 20,000 cPs, 4,000 to 500,000 cPs, 4,000 to 400,000 cPs, 4,000 to 300,000 cPs, 4,000 to 200,000 cPs, 4,000 to 100,000 cPs, 4,000 to It may be 50,000 cPs, 4,000 to 20,000 cPs, 5,000 to 500,000 cPs, 5,000 to 400,000 cPs, 5,000 to 300,000 cPs, 5,000 to 200,000 cPs, 5,000 to 100,000 cPs, 5,000 to 50,000 cPs, 5,000 to 20,000 cPs, for example, but is not limited thereto.

[0061] In the present invention, nanocellulose may have a degree of substitution of 0.20 or more, 0.20 to 0.90, 0.20 to 0.85, 0.20 to 0.80, 0.20 to 0.75, 0.35 to 0.90, 0.35 to 0.85, 0.35 to 0.80, 0.35 to 0.75, 0.45 to 0.90, 0.45 to 0.85, 0.45 to 0.80, 0.45 to 0.75, 0.55 to 0.90, 0.55 to 0.85, 0.55 to 0.80, 0.55 to 0.75, 0.65 to 0.90, 0.65 to It may have a degree of substitution of 0.85, 0.65 to 0.80, or 0.65 to 0.75, for example, but not limited to, a degree of substitution of 0.75.

[0062] When the degree of substitution of nanocellulose is 0.20 or higher, it can be dissolved in an alkaline aqueous solution, when the degree of substitution is 0.20 or higher, it can be dissolved in water, and when the degree of substitution is 0.5 to 0.8, it has the property of not precipitating even in an acidic solution.

[0063] In the present invention, the term “degree of substitution” is a term mainly used in cellulose chemistry, and means the average number of substituent groups attached per unit of a polymer.

[0064] In the present invention, the term "polymer" may also be referred to as a polymer, and may mean a compound formed by repeatedly polymerizing a plurality of unit substances.

[0065] In the present invention, if the polymer is a condensation polymer, it may mean the average number of substituents attached per base unit, and if the polymer is an addition polymer, it may mean the average number of substituents attached per monomeric unit.

[0066] In the present invention, the nanocellulose may be cellulose obtained from at least one selected from the group consisting of cotton, woody biomass, and non-woody biomass. Specifically, the woody biomass may be made of, but is not limited to, broadleaf trees or conifers. In addition, the non-woody biomass may be at least one selected from the group consisting of hemp, rice, oil palm, banana pseudostem, corn, sorghum, sugarcane, sunflower, bamboo, and reed, but is not limited thereto.

[0067] In one embodiment of the present invention, the nanocellulose may be obtained from banana pseudostem.

[0068] In the present invention, the nanocellulose may be manufactured by manufacturing the stem of the cotton, the woody biomass, or the non-woody biomass into chips and then finely crushing them. For example, the nanocellulose may be manufactured by manufacturing the trunk of a banana pseudostem into chips and then finely crushing them.

[0069] In the present invention, chips may be manufactured by crushing the cotton, the wood-based biomass, or the non-wood-based biomass, immersing it in chlorine dioxide (ClO2), reacting it with acetic acid (CH3COOH), and then washing it with distilled water.

[0070] In the present invention, the nanocellulose may be manufactured by re-immersing the chip in ethanol (C2H5OH) containing sodium hydroxide (NaOH) dissolved therein, reacting the chip with ethanol containing chloroacetic acid (CH2ClCOOH) dissolved therein, and then grinding the chip.

[0071] In the present invention, oil palm fibers may be composed of vascular bundles and parenchyma cells. Vascular bundles, similar to other wood fibers, are linear, long, and thin, whereas parenchyma cells are short and round. When pulping oil palm tree trunks, parenchyma cells may interfere with interfiber bonding, so a process for separating parenchyma cells before or after pulping may be necessary.

[0072] In the present invention, the separation of pulp cells before pulping is a process that utilizes the density difference between pulp cells and vascular bundles, and the separation of pulp cells after pulping is a process that utilizes a fiber separator (Bauer Mcnett), etc. The process of separating pulp cells using a fiber separator after pulping may be a process that separates long, rod-shaped vascular bundles and short, round-shaped pulp cells using wires of 28, 48, 100, and 200 mesh sizes for each section. Water must be continuously replenished and vibration applied to prevent pulp from clumping together or wires from becoming clogged.

[0073] Crushing of cotton, woody biomass, and non-woody biomass can be accomplished by grinding or a high-pressure homogenizer. Crushing conditions can be adjusted to ultimately crush cotton, woody biomass, and non-woody biomass into nano-sized particles, taking into account the quantity and condition of the cotton, woody biomass, and non-woody biomass.

[0074] In the present invention, the average particle diameter of nanocellulose may be 10 to 60 nm, 10 to 55 nm, 10 to 50 nm, 15 to 60 nm, 15 to 55 nm, 15 to 50 nm, 20 to 60 nm, 20 to 55 nm or 20 to 50 nm, for example, 20 to 50 nm, but is not limited thereto.

[0075] In the present invention, the soil coagulant may have a weight ratio of nanocellulose and starch of 80:20, 70:30, or 60:40, and for example, the weight ratio of nanocellulose and starch may be 50:50, but is not limited thereto.

[0076] In the present invention, the soil coagulant contains the starch in an amount of 0.001 to 0.1 wt%, 0.001 to 0.05 wt%, 0.001 to 0.02 wt%, 0.001 to 0.018 wt%, 0.001 to 0.016 wt%, 0.001 to 0.014 wt%, 0.001 to 0.012 wt%, 0.001 to 0.01 wt%, 0.001 to 0.005 wt%, 0.005 to 0.1 wt%, 0.005 to 0.05 wt%, 0.005 to 0.02 wt%, 0.005 to 0.018 wt%, 0.005 to 0.016 wt%, 0.005 to It may include 0.014 wt%, 0.005 to 0.012 wt%, 0.005 to 0.01 wt%, 0.01 to 0.1 wt%, 0.01 to 0.05 wt%, 0.01 to 0.02 wt%, 0.01 to 0.018 wt%, 0.01 to 0.016 wt%, 0.01 to 0.014 wt%, 0.01 to 0.012 wt%, and may include, for example, 0.01 wt%, but is not limited thereto.

[0077] In the present invention, the soil coagulant contains the nanocellulose in an amount of 0.001 to 0.1 wt%, 0.001 to 0.05 wt%, 0.001 to 0.02 wt%, 0.001 to 0.018 wt%, 0.001 to 0.016 wt%, 0.001 to 0.014 wt%, 0.001 to 0.012 wt%, 0.001 to 0.01 wt%, 0.001 to 0.005 wt%, 0.005 to 0.1 wt%, 0.005 to 0.05 wt%, 0.005 to 0.02 wt%, 0.005 to 0.018 wt%, 0.005 to 0.016 wt%, 0.005 to It may include 0.014 wt%, 0.005 to 0.012 wt%, 0.005 to 0.01 wt%, 0.01 to 0.1 wt%, 0.01 to 0.05 wt%, 0.01 to 0.02 wt%, 0.01 to 0.018 wt%, 0.01 to 0.016 wt%, 0.01 to 0.014 wt%, 0.01 to 0.012 wt%, and may include, for example, 0.01 wt%, but is not limited thereto.

[0078] In the present invention, the soil coagulant may have a water absorption amount of 200 g or more per 1 g, and specifically, the soil coagulant may have a water absorption amount of 200 g or more and 290 g or less, 200 g or more and 280 g or less, 200 g or more and 270 g or less, 210 g or more and 290 g or less, 210 g or more and 280 g or less, 210 g or more and 270 g or less, for example, 210 g, but is not limited thereto.

[0079] In the present invention, the moisture absorption rate of the soil coagulant may be 20,000% or more, and specifically, the moisture absorption rate of the soil coagulant may be 20,000% or more and 29,000% or less, 20,000% or more and 28,000% or less, 20,000% or more and 27,000% or less, 21,000% or more and 29,000% or less, 21,000% or more and 29,000% or less, 21,000% or more and 28,000% or less, 21,000% or more and 27,000% or less, for example, but is not limited thereto.

[0080] In the present invention, the soil coagulant may be decomposed by 80.0% or more for 28 days in the soil, and specifically, may be decomposed by 80.0% or more and 99.0% or less, 80.0% or more and 96.0% or less, 80.0% or more and 93.0% or less, 80.0% or more and 90.0% or less, 85.0% or more and 99.0% or less, 85.0% or more and 96.0% or less, 85.0% or more and 93.0% or less, 85.0% or more and 93.0% or less, 85.0% or more and 90.0% or less, 88.0% or more and 99.0% or less, 88.0% or more and 96.0% or less, 88.0% or more and 93.0% or less, 88.0% or more and 90.0% or less, and for example, may be decomposed by 89.0%. However, it is not limited to this.

[0081] In the present invention, the soil coagulant may be in the form of a liquid, gel or powder, but is not limited thereto.

[0082] The present invention also relates to a method for producing an environmentally friendly soil coagulant, comprising the following steps:

[0083] (S10) A step of obtaining nanocellulose having a viscosity of 3,000 to 500,000 cPs from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass;

[0084] (S20) A step of preparing a hydrogel by mixing the nanocellulose of the above step (S10) with starch;

[0085] (S30) A step of drying the hydrogel of the step (S20) to obtain a dried hydrogel; and

[0086] (S40) A grinding step for grinding the result of the above step (S30) to obtain an eco-friendly soil coagulant.

[0087] In the present invention, the nanocellulose of the step (S10) has a viscosity of 3,000 to 500,000 cPs, 3,000 to 400,000 cPs, 3,000 to 300,000 cPs, 3,000 to 200,000 cPs, 3,000 to 100,000 cPs, 3,000 to 50,000 cPs, 3,000 to 20,000 cPs, 4,000 to 500,000 cPs, 4,000 to 400,000 cPs, 4,000 to 300,000 cPs, 4,000 to 200,000 cPs, 4,000 to 100,000 cPs, 4,000 to 50,000 cPs, 4,000 to 20,000 cPs, 5,000 to 500,000 cPs, 5,000 to 400,000 cPs, 5,000 to 300,000 cPs, 5,000 to 200,000 cPs, 5,000 to 100,000 cPs, 5,000 to 50,000 cPs, 5,000 to 20,000 cPs, for example, but not limited to, 5,000 to 20,000 cPs.

[0088] In the present invention, the term 'dissolution' refers to a process in which nanocellulose is mixed with a sufficient amount of purified water, and the nanocellulose is dispersed and mixed in the purified water.

[0089] In the present invention, the step (S20) is a step of manufacturing a hydrogel using purified water, wherein the purified water is a solution that mixes nanocellulose and starch, and the purified water is neutral and may be any one selected from the group consisting of pH 6, 7, or 8, but is not limited thereto.

[0090] In the present invention, the solution in the step (S20) may contain 5.0 to 9.0 wt%, 5.0 to 8.5 wt%, 5.0 to 8.0 wt%, 5.0 to 7.5 wt%, 5.5 to 9.0 wt%, 5.5 to 8.5 wt%, 5.5 to 8.0 wt%, 5.5 to 7.5 wt%, 6.0 to 9.0 wt%, 6.0 to 8.5 wt%, 6.0 to 8.0 wt%, 6.0 to 7.5 wt%, 6.5 to 9.0 wt%, 6.5 to 8.5 wt%, 6.5 to 8.0 wt% or 6.5 to 7.5 wt% of nanocellulose based on the total weight of the solution, for example, it may contain 6.5 to 7.5 wt%, but is not limited thereto. no.

[0091] In the present invention, the solution of step (S20) may contain starch in an amount of 1.0 to 5.0 wt%, 1.0 to 4.5 wt%, 1.0 to 4.0 wt%, 1.0 to 3.5 wt%, 1.5 to 5.0 wt%, 1.5 to 4.5 wt%, 1.5 to 4.0 wt%, 1.5 to 3.5 wt%, 2.0 to 5.0 wt%, 2.0 to 4.5 wt%, 2.0 to 4.0 wt%, 2.0 to 3.5 wt%, 2.5 to 5.0 wt%, 2.5 to 4.5 wt%, 2.5 to 4.0 wt% or 2.5 to 3.5 wt% based on the total weight of the solution, for example, it may contain 2.5 to 3.5 wt%, but is not limited thereto.

[0092] In the present invention, the step of manufacturing the hydrogel in the step (S20) means a process in which starch expands due to heat and moisture, changes its physicochemical properties or structure, and increases its viscosity, water solubility, and / or volume.

[0093] In the present invention, the step (S20) may be a process in which nanocellulose and starch are dispersed by applying a shear force to water at room temperature or high temperature, and the nanocellulose and the starch are cross-linked with each other.

[0094] In the present invention, the step (S20) may be performed at a temperature of 60 to 90°C, 60 to 85°C, 60 to 80°C, 65 to 90°C, 65 to 85°C, 65 to 80°C, 70 to 90°C, 70 to 85°C or 70 to 80°C, and for example, may be performed at a temperature of 70 to 80°C, but is not limited thereto.

[0095] In the present invention, the step (S20) may be performed for 30 to 120 minutes, 30 to 90 minutes, 60 to 120 minutes, or 60 to 90 minutes, for example, it may be performed for 60 to 90 minutes, but is not limited thereto.

[0096] In the present invention, the step (S30) may be to place a mixture of cross-linked nanocellulose and starch in a sieve and dry it, and the drying method may be at least one selected from the group consisting of hot air, vacuum, far infrared, near infrared, spraying, freezing, and drying, but is not limited thereto.

[0097] In the present invention, the step (S30) may be dried at a temperature of 80 to 95°C, 80 to 90°C, 85 to 95°C, or 85 to 90°C, and for example, may be performed at a temperature of 85 to 90°C. If the drying step is performed at a temperature lower than 80°C, there may be a problem that the hydrogel is not completely dried but only partially dried, and if it is performed at a temperature higher than 95°C, there may be a problem that the hydrogel is carbonized or browned due to thermal denaturation, thereby reducing the absorbency of the absorbent.

[0098] In the present invention, the step (S30) may be performed by drying for 18 hours or more, and may be performed by drying for 18 to 48 hours, 18 to 44 hours, 18 to 40 hours, 18 to 36 hours, 18 to 32 hours, 18 to 28 hours, 20 to 48 hours, 20 to 44 hours, 20 to 40 hours, 20 to 36 hours, 20 to 32 hours, or 20 to 28 hours, and for example, may be performed by drying for 24 hours, but is not limited thereto.

[0099] In the present invention, the dried hydrogel of the step (S30) may be in the form of a dried film, but is not limited thereto.

[0100] In the present invention, the step (S40) may be to put the result of the step (S30) into a grinder and grind and crush it, and the grinding method may be at least one selected from the group consisting of a roll mill, a pin mill, a bead mill, a basket mill, a catamill, a ball mill, a grind mill, a cutter mill, and a crusher, but is not limited thereto.

[0101] The present invention also comprises starch and nanocellulose,

[0102] The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass,

[0103] The above nanocellulose has a viscosity of 3,000 to 500,000 cPs,

[0104] The present invention relates to a forest fire spread prevention agent including an eco-friendly soil coagulant, wherein the aldehyde group of the starch is a polymer that is acetal crosslinked with the hydroxyl group of the nanocellulose.

[0105] The present invention also comprises starch and nanocellulose,

[0106] The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass,

[0107] The above nanocellulose has a viscosity of 3,000 to 500,000 cPs,

[0108] The present invention relates to a forest damage restoration agent including an eco-friendly soil coagulant, wherein the aldehyde group of the starch is a polymer formed by acetal crosslinking with the hydroxyl group of the nanocellulose.

[0109] Hereinafter, the present invention will be described in detail with the following examples to aid understanding. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the examples described below. The examples of the present invention are provided by way of example to aid in a concrete understanding of the present invention.

[0110]

[0111] Manufacturing Example 1. Manufacturing of soil coagulant containing starch and nanocellulose

[0112] 1-1. Production of nanocellulose

[0113] First, banana pseudostems are powdered and soaked in ethanol. After soaking in ethanol, ethanol containing NaOH is added and reacted at 70°C for 1 hour to activate the material. Monochloroacetic acid (MCA) is added to the activated material in ethanol and a chemical pretreatment reaction is performed at 70°C for 1 hour. After that, the material is washed and ground into nano-sized particles using a grinder to produce nanocellulose. The produced nanocellulose was confirmed to have a particle size (diameter) of 20 to 50 nm by transmission electron microscopy (TEM).

[0114] In addition, as a result of measuring the viscosity of the above-mentioned manufactured nanocellulose, it was confirmed that it had high viscosity, with a viscosity of 5,000 to 20,000 cPs in a 1% suspension state.

[0115] 1-2. Preparation of soil coagulant

[0116] A soil coagulant was prepared by mixing starch with the nanocellulose manufactured above, and the starch was used as a 1:1 mixture of tapioca and corn.

[0117] The nanocellulose and starch obtained by nano-processing are mixed at a certain ratio and gelled. The specific ratio is as shown in the composition of Table 1 below, and in each example, the nanocellulose is 50 g for Example 1, 60 g for Example 2, 70 g for Example 3, and 80 g for Example 4, and the weight ratio of nanocellulose and starch is 50:50 for Example 1, 60:40 for Example 2, and 70:30 for Example 3. The mixture was stirred at 70°C for 1 hour so that the nanocellulose and starch could gel and physical crosslinking and starch gelatinization could occur inside the gel.

[0118] Composition and content (weight %) for total 5,000g Example 1 Example 2 Example 3 Nanocellulose 0.01 0.01 2 0.01 4 Starch 0.01 0.00 8 0.00 6 Purified water To 100 To 100 To 100

[0119]

[0120] After stirring, the gelled mixture was dried at 80°C for 24 hours and ground in a mixer to obtain a soil aggregate of the example in Table 1 with a total mass of 5,000 g including purified water.

[0121] Experimental Example 1. Measurement of moisture absorption and moisture absorption rate of soil coagulant

[0122] In order to confirm the composition of a soil coagulant that exhibits optimal gel-forming ability upon water immersion, the water absorption rates were compared through Examples 1 to 3 and Comparative Example 1 (synthetic polymer absorbent, SAP 100%) and Comparative Example 2 (electron beam cross-linked CMC).

[0123] Moisture absorption and absorption rate were measured using the modified tea bag method (MOISTURE ABSORPTION / RETENTION, DRY STARCH POWDERS Modified Teabag Method) of the U.S. Environmental Protection Agency (EPA).

[0124] First, 1 L of distilled water was filled into a beaker, the beaker was placed in a constant temperature water bath to adjust the temperature to 37 ℃, and then equilibrated for 30 minutes. The weight of the empty non-woven tea bag (T ovendry ) and measure the absorbent weight (S ovendry ) were each fixed at 0.20 g.

[0125] Afterwards, the empty non-woven tea bags and the tea bags with absorbent inserts were soaked in a beaker for 1 hour to 112 days, and then the tea bags were recovered and the moisture outside the tea bags was removed using a paper towel. The wet weight of the empty non-woven tea bags (T swelling ) and the wet weight of the tea bag with the absorbent inserted [(T+S) swelling ], the weight of the absorber (S ovendry ) was measured, the measured value was substituted into the following mathematical formula 1, and the moisture absorption rate was calculated, and the results are shown in Tables 2 to 5 and Figs. 3 to 6. The same process was performed for Comparative Example 1 and Comparative Example 2. (In Figs. 3 to 6, EcoSAP = Example 1, Chemical SAP = Comparative Example 1, Other Natural Absorbent = Comparative Example 2)

[0126]

[0127]

[0128] Absorption capacity: moisture absorption capacity

[0129] Absorption over time (g / g)Example 1Example 2Example 3Comparative Example 1Comparative Example 21 hours576265335312 hours698189345323 hours808394346424 hours9598101346495 hours115126131348616 hours13716119634762

[0130]

[0131] Absorption over time (g / g)Example 1Example 2Example 3Comparative Example 1Comparative Example 21 day270281290345622 days276280294348633 days277279289345634 days275282292345625 days27328129534665

[0132]

[0133] Absorption over time (g / g)Example 1Example 2Example 3Comparative Example 1Comparative Example 27 days2752842933436114 days2772852903475721 days2432652713335828 days21024826434251

[0134]

[0135] Absorption over time (g / g)Example 1Example 2Example 3Comparative Example 1Comparative Example 228 days2102482643425156 days1762012253434784 days14516418934742112 days12314717234040

[0136]

[0137] As can be seen in Table 2, the absorption amounts within 6 hours of Examples 1 to 3 were measured to be about 137 to 196 g / g, which was lower than the absorption amount of Comparative Example 1, which was a synthetic polymer absorbent absorbent (SAP), measured to be 335 g / g.

[0138] However, compared to the absorption amount of Comparative Example 2, which was 62 g / g, it was found to be +220.9 to 316.1% higher.

[0139] As can be seen in Table 3, the maximum absorption amounts of Examples 1 to 3, which appear after one day, were measured to be 277 to 295 g / g, which is 79.5 to 84.7% of the maximum absorption amount of Comparative Example 1, confirming that the performance is not significantly reduced. On the other hand, Comparative Example 2 was confirmed to show a significantly lower absorption amount than Examples and Comparative Example 1 at the level of 18.6%.

[0140] As can be seen in Tables 4 and 5, the absorption amount of Example and Comparative Example 2 showed a tendency to decrease slightly due to biodegradation, whereas the absorption amount of Comparative Example 1 was confirmed to be maintained steadily as it was not biodegraded.

[0141] That is, Examples 1 to 3 had significantly higher absorption amounts than Comparative Example 2, and showed a maximum absorption amount similar to Comparative Example 1, while simultaneously confirming that biodegradation occurred.

[0142]

[0143] Experimental Example 2. Evaluation of Biodegradability of Soil Coagulant

[0144] The biodegradability of soil coagulants was evaluated by measuring the dissolved organic carbon (DOC) through the final aerobic biodegradability of organic matter in a water-liquid medium according to the KS I ISO 7827 method for measuring aquatic biodegradability, and evaluating it using the following mathematical formula 2. Specifically, the soil coagulant of Example 1 was evaluated by measuring it for 28 days.

[0145]

[0146]

[0147] After measuring the average DOC concentration of the test flask for 28 days and calculating it using the above formula, the biodegradability of the soil coagulant of Example 1 was found to be 89.0%.

[0148] Experimental Example 3. Measurement of Non-toxicity and Stability of Soil Coagulants

[0149] In order to confirm the stability of the manufactured soil coagulant, an experiment was conducted on 5 g of a sample of Example 1 at a temperature of (40±2)℃ and a humidity of (75±5)%, and qualitative tests were conducted at the beginning (0 week), 12 weeks, and 24 weeks.

[0150] 3-1. Characteristics and Verification Test

[0151] The appearance test was performed by placing 5 g of the above sample on a watch glass and visually checking, and the confirmation test was performed by 1) mixing 1 g of the above sample with 50 ml of warm water to make a viscous solution, then adding 10 ml of barium chloride to 10 ml of the above solution and checking for a white fine precipitate, 2) adding water to 1 ml of the above solution to make 10 ml, then adding 0.5 ml of chromotropic acid solution to 1 drop, heating for 10 minutes, and checking for a reddish purple color, and 3) adding 1 drop of iodine solution to 5 ml of the above solution and checking for a blue-violet color.

[0152] As a result of the test, 1) white fine sediment was confirmed, 2) red color was confirmed, and 3) blue color was confirmed.

[0153] 3-2. Purity test

[0154] Alkali Test

[0155] Dissolve 50 ml of water in 0.5 g of the above sample to make a test solution, then add 4 drops of phenolphthalein solution to 10 ml of the above test solution and check whether a faint red color appears.

[0156] The test results showed no faint red color.

[0157] Chloride Test

[0158] Add 10 ml of diluted nitric acid to 10 ml of the test solution, mix, heat in a water bath until cotton-like precipitate forms, cool, centrifuge at 3,000 rpm for 5 minutes, take the supernatant, wash the precipitate with 10 ml of water three times, centrifuge again for 5 minutes, combine the supernatant and the washed solution, add water to make 200 ml, take 50 ml, and compare with 0.45 ml of 0.01 mol / L hydrochloric acid as a control solution.

[0159] The test results confirmed that there was no chloride as it was not darker than the comparison solution.

[0160] Sulfate Test

[0161] Mix 1 ml of hydrochloric acid with 10 ml of the test solution of the above alkaline test, heat in a water bath until cotton-like precipitates form, cool, centrifuge at 3,000 revolutions per minute for 5 minutes, and then wash three times with 10 ml of water as in the above chloride test, and repeat the same process as in the above chloride test. The comparison solution is compared with 0.40 ml of 0.005 mol / L sulfuric acid.

[0162] The test results showed that it was not as dark as the control solution, confirming that there was no sulfate.

[0163] Silicate Test

[0164] Weigh precisely 1 g of the above sample, place it in a platinum dish, heat it on a low flame to carbonize, then incinerate it by igniting it at 500℃, cool it, add 20 ml of diluted hydrochloric acid, cover the watch glass, and boil gently for 30 minutes. Remove the watch glass, heat it in a water bath to evaporate to dryness, heat again for 1 hour, add 10 ml of boiling water, mix, filter using a quantitative filter paper (Type 5 C), wash the residue with boiling water, add silver nitrate solution to the washings, dry it together with the filter paper when it is no longer cloudy, and ignite again until the weight becomes odorless.

[0165]

[0166] m0: Weight of the plate (g)

[0167] m1: Weight of the plate and sample before heating (g)

[0168] m2: Weight of the plate and specimen after heating (g)

[0169] As a result of the test using the above mathematical formula 3, the average for week 0 was 1.1%, for week 12 it was 0.51%, and for week 24 it was 0.30%.

[0170] Heavy Metal Test

[0171] The above 1 g of sample is processed according to the second method of the general test method "66. Heavy metal test method" of the Korean Pharmacopoeia (notified by the Ministry of Food and Drug Safety), and 2 ml of lead standard solution is added as the comparison solution.

[0172] The test results showed that the solution was not more concentrated than the control solution, confirming that there were no heavy metals.

[0173] Arsenic Test

[0174] Slowly add 20 ml of nitric acid to 2.5 g of the above sample, heat until it becomes a fluid phase, then cool, add 5 ml of sulfuric acid, heat until white smoke is produced, repeat until it becomes colorless or light yellow, cool, add 15 ml of saturated ammonium hydroxide solution, heat until white smoke is produced, then add water, and use 25 ml as the test solution, and test according to the standard color preparation and operation method in the general test methods "22. Arsenic Test Method" of the Korean Pharmacopoeia (Notification of the Ministry of Food and Drug Safety).

[0175] The test results were not more concentrated than the standard solution, confirming that there was no arsenic.

[0176]

[0177] The present invention aims to provide a biodegradable, eco-friendly soil coagulant that is non-toxic and biodegradable and can absorb a large amount of moisture, and can function as a forest fire spread prevention agent and a forest damage restoration agent.

Claims

1. Contains starch and nanocellulose, The above nanocellulose is obtained from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass, The above nanocellulose has a viscosity of 3,000 to 500,000 cPs, An eco-friendly soil coagulant, wherein the aldehyde group of the starch is a polymer formed by acetal crosslinking with the hydroxyl group of the nanocellulose.

2. In paragraph 1, An environmentally friendly soil coagulant, wherein the above starch is at least one selected from the group consisting of root starch, cereal starch, and glutinous cereal starch.

3. In paragraph 1, An eco-friendly soil coagulant, wherein the substitution degree of the above nanocellulose is 0.20 or higher.

4. In paragraph 1, The above nanocellulose is an eco-friendly soil coagulant having an average particle diameter of 10 to 60 nm.

5. In paragraph 1, An environmentally friendly soil coagulant comprising 0.001 to 0.1 wt% of the starch and 0.001 to 0.1 wt% of the nanocellulose based on the total weight of the soil coagulant.

6. In paragraph 1, The above soil coagulant is an environmentally friendly soil coagulant having a moisture absorption capacity of 200 g or more per 1 g.

7. In paragraph 1, An environmentally friendly soil coagulant having a moisture absorption rate of 20,000% or more.

8. In paragraph 1, The above soil coagulant is an environmentally friendly soil coagulant that is decomposed by more than 80.0% in soil over 28 days.

9. In paragraph 1, The above soil coagulant is an environmentally friendly soil coagulant made of liquid, gel or powder.

10. A method for manufacturing an eco-friendly soil aggregate comprising the following steps: (S10) A step of obtaining nanocellulose having a viscosity of 3,000 to 500,000 cPs from at least one selected from the group consisting of cotton, woody biomass and non-woody biomass; (S20) A step of preparing a hydrogel by mixing the nanocellulose of the above step (S10) with starch; (S30) A step of drying the hydrogel of the step (S20) to obtain a dried hydrogel; and (S40) A grinding step for grinding the result of the above step (S30) to obtain an eco-friendly soil coagulant.

11. In paragraph 10, A method for producing an eco-friendly soil coagulant, wherein the above step (S20) is performed by mixing for 30 to 120 minutes under temperature conditions of 60 to 90°C.

12. In paragraph 10, A method for producing an eco-friendly soil coagulant, wherein the above step (S30) is performed by drying for 18 hours or more under temperature conditions of 80 to 95 ℃.

13. A forest fire spread prevention agent containing the soil coagulant of paragraph 1.

14. Forest damage restoration agent containing soil coagulant of paragraph 1.

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