Absorptive material

Abstract

The purpose of the present invention is to provide an absorptive material capable of exhibiting good absorption performance with respect to a water-containing composition containing an organic substance. Specifically, the present invention provides: an absorptive material that is for a water-containing composition containing an organic substance, and that contains a cellulose material such as pulp having a fiber length of 0.2-5 mm and a fiber width of 10-50 um; and a method that is for treating a water-containing composition containing an organic substance, and that comprises bringing a dehydrating agent into contact with the water-containing composition containing an organic substance and causing an absorptive material to absorb a component containing water in the water-containing composition. The cellulose material is preferably a pulp having a whiteness of 10-95% or a solid content of at least 15%. Further, the cellulose material is preferably hardwood or softwood pulp, or kraft pulp.

Description

Absorbent

[0001] The present invention relates to an absorbent, and more particularly to an absorbent for a water-containing composition containing organic substances.

[0002] Wastes discharged from factories, agricultural facilities, households, etc. are usually discarded through incineration. When a large amount of moisture is contained in the waste, heat is used for its evaporation, the energy required for the combustion of the waste increases, and the problems of increased treatment costs and adverse environmental impacts arise. Among them, food waste contains a lot of moisture, and its reduction is required. Patent Document 1 describes that a plant-based fiber or dry powder such as paper pulp such as cardboard paper powder and konjac powder, etc. mixed at a predetermined ratio can improve the handling in the treatment of waste liquid of sludge derived from water-based paints, etc. Patent Document 2 describes that food waste, raw garbage, etc. can be efficiently reduced in water content with low energy by heating and drying. Patent Document 3 describes that in a heating and drying plant for food residues, the heat efficiency of the plant can be increased by reusing the recovered dry gas and condensed water.

[0003] Japanese Patent Application Laid-Open No. 2008-264753, Patent No. 4505472, Japanese Patent Application Laid-Open No. 2003-019475

[0004] However, the method of Patent Document 1 has problems in terms of absorption efficiency. Also, in the methods of Patent Documents 2 and 3, since energy for heating is required and the use of special equipment is assumed, efficient absorption is difficult.

[0005] An object of the present invention is to provide an absorbent that can exhibit good absorption performance for a water-containing composition containing organic substances.

[0006] The present invention provides the following [1] to [7]: [1] An absorbent material for an organic-containing aqueous composition, comprising a cellulose material having a fiber length of 0.2 to 5 mm and a fiber width of 10 to 50 μm. [2] The absorbent material according to [1], wherein the cellulose material is pulp. [3] The absorbent material according to [2], wherein the whiteness of the pulp is 10 to 95%. [4] The absorbent material according to [2], wherein the solids content of the pulp is 15% or more. [5] The absorbent material according to [2], wherein the pulp is hardwood or softwood pulp. [6] The absorbent material according to any one of [2] to [5], wherein the pulp is kraft pulp. [7] A method for treating an organic-containing aqueous composition, comprising contacting the organic-containing aqueous composition with a dehydrating agent according to any one of [1] to [6], and allowing the absorbent material to absorb the water-containing components in the aqueous composition.

[0007] According to the present invention, an absorbent is provided that can absorb and retain liquid components and components (mainly water-soluble components) dissolved, suspended, or dispersed in the liquid within an organic-containing aqueous composition, suppress syneresis, increase the solid content of the aqueous composition, and obtain a solid with low fluidity, thereby exhibiting good absorption performance.

[0008] Figure 1 is a graph showing the relationship between the pulp addition rate and the solid content % in the absorption tests of grated radish (Comparative Example 1, Examples 1-3) and bean sprouts (Comparative Example 2, Examples 4-6). Figure 2 is a graph showing the relationship between the pulp addition rate and the recovered water in the absorption tests of grated radish (Comparative Example 1, Examples 1-3) and bean sprouts (Comparative Example 2, Examples 4-6). Figure 3 is a photograph showing the appearance of the containers containing the absorbed mixtures of Comparative Example 2 (left) and Example 7 (right). Figure 4 is a photograph showing the appearance of the containers containing the absorbed mixtures of Comparative Example 2 (left) and Example 7 when they are laid on their sides. Figure 5 is a photograph showing the appearance of the container containing the absorbed mixture of Example 10 (bean sprouts and pulp) when it is laid on its side. Figure 6 is a photograph showing the appearance of the container containing the absorbed mixture (bean sprouts and sawdust) of Comparative Example 5 when it is laid on its side. Figure 7 is a photographic image showing the appearance of the container containing the mixture (bean sprouts only) after absorption treatment in Comparative Example 6 when it is laid on its side.

[0009] [1. Absorbent Material] The absorbent material of the present invention contains cellulose material as an active ingredient. Cellulose material is a material whose main component is cellulose.

[0010] [1.1 Cellulose Raw Materials] The cellulose contained in cellulose materials originates from cellulose raw materials, which are the raw materials for cellulose materials. Cellulose raw materials are usually wood, and may be hardwoods, softwoods, or a combination of two or more of these. Examples of broad-leaved trees include plants of the genera Fagus (e.g., beech), Tilia (e.g., linden), Betula (e.g., white birch, Japanese birch), Populus (e.g., poplar), Eucalyptus (e.g., eucalyptus), Acacia (e.g., acacia), Quercus (e.g., oak, Japanese evergreen oak, sawtooth oak), Acer (e.g., Japanese maple), Kalopanax (e.g., Japanese holly), Ulmus (e.g., Japanese elm), Paulownia (e.g., paulownia), Magnolia (e.g., Japanese magnolia), Salix (e.g., willow), Aesculus (e.g., horse chestnut), Zelkova (e.g., zelkova), Cornus (e.g., Cornus), and Fraxinus (e.g., Japanese ash), with plants of the genus Eucalyptus being preferred. Examples of coniferous trees include the genera Cryptomeria (e.g., Japanese cedar), spruce (e.g., Yezo spruce), larch (e.g., Japanese larch, Western larch, Tamalac), pine (e.g., Japanese black pine, Japanese white pine, Radiata pine, Eastern white pine), fir (e.g., Sakhalin fir, Abies firma, Western fir), yew (e.g., Japanese yew), cypress (e.g., Japanese cedar, Yellow cedar), and spruce (e.g., Japanese fir, Japanese spruce, Spruce, Citka). Examples of suitable cellulose raw materials include spruce (Picea japonica, Eastern spruce), Podocarpus (e.g., Podocarpus macrophyllus), Chamaecyparis (e.g., Chamaecyparis obtusa, Chamaecyparis cypress, Chamaecyparis lawsonii), Podocarpus (e.g., Podocarpus japonica, Douglas fir, Western hemlock), Thuja (e.g., Thuja chinensis, Thuja occidentalis), Tsuga (e.g., Tsuga sieboldii, Tsuga diversifolia), and Thuja genus (e.g., Thuja japonica). Plants of the genera Cryptomeria, Pinus, Larch, and Chamaecyparis are preferred. On the other hand, non-woody materials may also be used as cellulose raw materials, such as bamboo, hemp, jute, kenaf, agricultural waste, and paper (e.g., recycled paper, printing paper). Wood (coniferous trees, broad-leaved trees) is preferred as the cellulose raw material.

[0011] [1.2 Optional Components] Cellulose materials may contain components other than cellulose. Examples include components other than cellulose derived from cellulose raw materials, by-products in the manufacturing process, and optional additives (e.g., preservatives, stabilizers, additives used in pulp and paper manufacturing). Examples of components derived from cellulose raw materials include lignin, cellulose, hemicellulose, dextrin, glucan, and other sugars. Other sugars include, for example, monosaccharides (e.g., trisaccharides such as aldotriose and ketotriose; tetrasaccharides such as erythrose, threose, and erythrulose; pentoses such as xylose, ribose, arabinose, lyxose, ribulose, and xylulose; hexoses such as mannose, allose, altrose, lucose, gross, idose, galactose, talose, psicose, fructose, sorbose, tagatose, fucose, fructose, rhamnose, and heptoses such as sedoheptulose), oligosaccharides (e.g., disaccharides such as sucrose, lactose, maltose, trehalose, turanose, and cellobiose; raffinose, melegitose, and maltotriose) Examples of by-products include trisaccharides such as sucrose, tetrasaccharides such as acarbose and stachyose, oligosaccharides such as xylooligosaccharides, cellooligosaccharides, fructooligosaccharides, galactooligosaccharides, and mannanoligosaccharides, polysaccharides (for example, glycogen, starch (amylose, amylopectin), reducing sugars, and modified sugars. Examples of by-products include sodium sulfate, sodium sulfite, sodium chloride, magnesium sulfate, magnesium sulfite, magnesium chloride, calcium sulfate, calcium sulfite, calcium chloride, ammonium sulfate, ammonium sulfite, ammonium chloride, sodium hydroxide, and as inorganic fillers and pigments for coated and uncoated paper, calcium carbonate and kaolin.

[0012] The amount of the above optional components varies depending on the type of cellulose raw material, manufacturing conditions, etc., and therefore it is difficult to specify it uniquely; however, any amount that results in a kappa number of 1 or more is acceptable. When optional components are included, it is preferable that the optional components other than cellulose, hemicellulose, and lignin be in small amounts, and their proportion to the cellulose material is, for example, 10% by weight or less, 8% by weight or less, 5% by weight or less, preferably 1% by weight or less, and more preferably 0.5% by weight or less.

[0013] [1.3 Examples of Cellulose Materials] An example of a cellulose material is pulp. Pulp is usually made by unraveling plant fibers one by one, and it consists of very fine fibers compared to other cellulose materials such as sawdust, and this fine structure allows it to exhibit high absorbency. In addition, the fibers of pulp are very fine, and the surface area per unit weight is larger than that of other cellulose materials such as sawdust, which also contributes to its high absorbency. Furthermore, pulp has a lower lignin content and a higher cellulose and hemicellulose content compared to sawdust, which also contributes to its high absorbency.

[0014] -Pulp- Pulp is produced by pulping the above-mentioned cellulose raw material, and the production conditions or methods are not particularly limited, as long as they include the process of pulping the wood chips mentioned above. Examples of pulping methods include chemical methods that involve pulping, such as the kraft process, sulfite process, soda process, and polysulfide process (chemical pulp); mechanical methods that use equipment such as refiners and grinders (mechanical pulp); and methods that involve pulping by mechanical force after chemical pretreatment (semi-chemical pulp), which are commonly used in the paper industry, but are not limited to these. Further processing such as beating may also be performed. The resulting pulp may be unbleached pulp, bleached pulp, beaten pulp, or unbeaten pulp. Examples of chemical pulp include sulfite pulp and kraft pulp. Pulp is classified into softwood pulp and hardwood pulp depending on the raw material, and both can be used. Furthermore, pulp is classified into several types depending on the raw materials and processing during manufacturing: unbleached softwood kraft pulp (NUKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), bleached hardwood kraft pulp (LBKP), bleached softwood dissolved kraft pulp (NDKP), bleached hardwood dissolved kraft pulp (LDKP), bleached softwood sulfite pulp (NBSP), dissolved kraft pulp (DKP), and unbleached hardwood sulfite pulp (L Pulp is classified into several types based on its manufacturing method, including USP, bleached hardwood sulfite pulp (LBSP), oxygenated deligninized hardwood kraft pulp (LOKP), unbleached softwood kraft pulp (NUKP), bleached softwood kraft pulp sheets (NBKP), unbleached softwood sulfite pulp (NUSP), bleached dissolved softwood sulfite pulp (NDSP), bleached dissolved hardwood sulfite pulp (LDSP), oxygenated deligninized softwood kraft pulp (NOKP), and recycled pulp. Mechanical pulp is further classified into several types based on its manufacturing method, such as wood pulp (GP), pressurized wood pulp (PGW), refined wood pulp (RGP), thermomechanical pulp (TMP), chemothermetic pulp (CTMP), alkali hydrogen peroxide mechanical pulp (APMP), and alkali hydrogen peroxide thermomechanical pulp (APTMP). Of these, chemical pulps such as kraft pulp and sulfite pulp are preferred.

[0015] The form of the pulp is not particularly limited and may include, for example, slurry, gel, cotton-like, okara-like, porridge-like, sheet-like, or powder-like. These forms can be adjusted depending on the manufacturing conditions (e.g., whether or not dehydration, drying, grinding, or crushing processes are included, and the conditions under which they are carried out).

[0016] [1.4 Physical Properties of Cellulose Materials] Cellulose materials preferably exhibit the following physical properties. This allows for adjustment of the microstructure, surface area, and chemical structure of the cellulose material, thereby further enhancing its absorption capacity.

[0017] -Fiber Length- The average fiber length of the cellulose material is usually 0.2 mm or more, preferably 0.3 mm or more, and more preferably 0.4 mm or more. The upper limit is usually 5 mm or less, preferably 4 mm, and more preferably 3 mm or less. The average fiber length of the cellulose fibers can be determined by an image analysis type fiber analyzer, such as a Valmet Fractionator or an ABB L&W Fiber Tester Plus. Specifically, for example, 300 ml of an aqueous dispersion diluted to contain 0.1 g of solid cellulose fibers is subjected to an image analysis type fiber analyzer (product name: L&W Fiber Tester Plus, manufactured by ABB), and measurements are taken for 300 seconds to determine the length-weighted fiber length (length-weighted average fiber length) (n=2). At that time, on the Sample type screen where the measurement conditions are defined, set the Max value of Fines Limit to 0.2 and the Min value of Length class 1 to 0.2 before performing the measurement.

[0018] -Fiber width- The average fiber width of cellulose material is usually 10 μm or more, preferably 12 μm or more, and more preferably 15 μm or more. The upper limit is usually 50 μm or less, preferably 40 μm or less, and more preferably 35 μm or less. The average fiber width of cellulose fibers can be determined as the length-weighted fiber width in the same way as the average fiber length.

[0019] -Whiteness- The cellulose material has a whiteness of 10% or more, preferably 15% or more, and more preferably 18% or more, based on ISO 2470. The upper limit is usually 95% or less, preferably 90% or less, and more preferably 88% or less.

[0020] - Copper Number - Cellulose material is preferably of a copper number greater than 1, more preferably 3 or higher, 5 or higher, and more preferably 7 or higher. This allows lignin to remain and the material to have rigidity, so it can exhibit good dewatering performance even when used at high dewatering pressure. The upper limit is usually 120 or less, preferably 100 or less, more preferably 80 or less, and even more preferably 70 or less, and 60 or less. The copper number can be measured in accordance with JIS P 8211:2011.

[0021] The kappa number can be adjusted, for example, by the type of cellulose raw material and the conditions of the deligninization process.

[0022] -Solid Content- The solid content percentage of the cellulose material is usually 15% by weight or more, preferably 20% or more, more preferably 30% by weight or more, even more preferably 40% by weight or more, and even more preferably 45% by weight or more. This may enable more efficient dewatering. There is no particular upper limit, but for example, it is 97% by weight or less, 95% by weight or less, or 93% by weight or less.

[0023] - Ash Content - The ash content of the cellulose material should be 1.5% by weight or less, preferably 1.0% by weight or less, and more preferably 0.8% by weight or less. Ash content measurement can be performed in accordance with JIS P 8251:2003.

[0024] [1.5 Method for Manufacturing Cellulose Materials] Cellulose materials can be manufactured from the above-mentioned cellulose raw materials. For example, if the cellulose material is chemical pulp and its processed products, it can be manufactured by subjecting the cellulose raw materials to treatment such as pulping.

[0025] -Chips- When the cellulose raw material is wood, it is usually first processed into wood chips. One method of manufacturing wood chips is to cut down a plant, remove the bark from the woody parts (trunk and branches), and then cut or crush them.

[0026] -Digestion- The wood chips are then subjected to digestion. Examples of digestion methods include soda digestion, Kraft digestion, organosolve digestion, polysulfide digestion, and modified versions thereof, with soda digestion and Kraft digestion being preferred. The former is preferred in terms of low hemicellulose content, while the latter is preferred in terms of environmental and economic considerations. Kraft digestion is a method of digestion using alkaline chemicals such as sodium hydroxide, potassium hydroxide, and sodium carbonate, and sulfur-containing chemicals such as sodium sulfide and sodium sulfite. Additives such as quinone-based digestion aids and polysulfides can be used as needed. These additives do not need to be used if digestion can be performed with alkaline chemicals alone. Pre-hydrolysis may also be performed before Kraft digestion. After digestion, neutralization, washing, deliquidation, bleaching, and drying may be performed as described below.

[0027] - Delignin Treatment - Pulp after pulping may undergo delignin treatment. Examples of delignin treatment include oxygen delignin treatment. Oxygen delignin treatment is a process in which lignin is ionized under an alkaline atmosphere to generate a large amount of phenolic hydroxyl groups, which are then reacted with oxygen molecules. This allows the lignin to be broken down into smaller molecules and dissolved in alkali. Sodium hydroxide and potassium hydroxide can be used as alkalis in oxygen delignin treatment, and oxygen gas can be obtained from cryogenic separation, PSA (Pressure Swing Adsorption), VSA (Vacuum Swing Adsorption), etc. There are no particular limitations on the reaction conditions for oxygen delignin treatment, but for example, the oxygen pressure can be 3 to 9 kg / cm². ２ , more preferably 4 to 7 kg / cm³ ２The alkali addition rate can be 0.5 to 4% by weight, the temperature can be 80 to 140°C, and the processing time can be 20 to 180 minutes. Other conditions can be those known. The oxygen delignin treatment can be performed once or multiple times. The whiteness of the pulp after oxygen delignin treatment is preferably 25 to 60%, and more preferably 30 to 55%, based on ISO 2470.

[0028] - Washing Process - The pulp after pulping may undergo washing and bleaching treatments. Bleaching treatment can yield pulp with higher whiteness. Examples of bleaching treatments include chlorine treatment (C), chlorine dioxide bleaching (D), alkaline extraction (E), hypochlorite bleaching (H), hydrogen peroxide bleaching (P), alkaline hydrogen peroxide treatment (Ep), alkaline hydrogen peroxide / oxygen treatment (Eop), ozone treatment (Z), chelation treatment (Q), and combinations of two or more of these treatments, applied to pulp that has been deligned by an optional conventional method. Examples of combinations (sequences) of two or more processes include D-E / P-D, C / D-E-H-D, Z-E-D-PZ / D-Ep-D, Z / D-Ep-D-P, D-Ep-D, D-Ep-D-P, D-Ep-P-D, Z-Eop-D-D, Z / D-Eop-D, and Z / D-Eop-D-E-D (the " / " in the sequence means that the processes before and after the " / " are performed consecutively without washing). The bleaching process is not limited to the above examples and may be a method commonly used. The pulp that has undergone the bleaching process is usually in a fluid state (fluid pulp). The whiteness of the bleached pulp is preferably 60 to 95%, more preferably 70 to 90%, and even more preferably 75 to 88%, based on ISO 2470. The whiteness of unbleached pulp is preferably 10-60%, more preferably 15-60%, and even more preferably 18-55%, based on ISO 2470.

[0029] - Grinding Process - The pulp after pulping can be used as is as a cellulose material, but it may be further subjected to grinding if necessary. This allows for the production of pulp in various forms, such as powder or cotton-like. Grinding can be carried out using a grinder. Examples of grinders include cutting mills, impact mills, airflow mills, hammer mills, roll mills, roller mills, media mills, media stirring mills, and freeze grinders, and one type may be used alone or two or more types may be used in combination. - Unfrozen Process - The pulp after pulping may be subjected to unfrozen (defibration) processing. This allows for the production of pulp in various forms, such as cotton-like. Unfrozen processing is a process that loosens the fibers constituting the material to be processed (e.g., pulp, pulp sheet) without substantially cutting them, and can be carried out using a defibration machine such as a wet pulp defibration machine, a pulp defibration machine, or a dry defibration machine. Preferably, the unfrozen processing may be carried out on a pulp sheet (dry pulp sheet). This allows for the production of cotton-like cellulose material. On the other hand, pulp (wet pulp) may be subjected to a crushing treatment (crushing treatment after disintegration and dewatering treatment as necessary), preferably followed by dewatering treatment. This allows for the efficient production of a pulp-like cellulose material. When defibrating dry pulp, it is preferable to use a dry defibrator. The physical properties of the cellulose material can be easily adjusted by adjusting the screen diameter and the number of treatment cycles of the defibrator.

[0030] -Neutralization, Washing, Dehydration, and Drying Treatment- If necessary, one or more of the following treatments may be performed along with the crushing and pulverization treatment: neutralization, washing, dehydration, and drying. This may facilitate the control of the physical properties of the cellulose material. These treatments can be performed before or after the crushing treatment. Examples of drying methods include airflow drying, freeze-drying, spray drying, shelf drying, drum drying, belt drying, drying by spreading thinly on a glass plate, fluidized bed drying, microwave drying, vacuum drying with a heated fan, and vacuum (deaeration) drying. Airflow drying is preferred because it can dry instantly and keep the product temperature low. Dehydration can be performed using dehydration equipment such as a dewatering machine or dryer. Examples of dewatering equipment include screw presses, centrifugal separators (centrifugal dewaterers), belt presses, tube presses, rotary presses, airflow dryers (e.g., airflow dryers equipped with rotating teeth such as airflow dryers with built-in classifiers), forced-air dryers (e.g., stationary forced-air dryers), microwave dryers, vacuum dryers, fluidized bed dryers, and freeze dryers. Of these, screw presses, airflow dryers, and forced-air dryers are preferred. Dewatering equipment may be used individually or in combination of two or more types.

[0031] The pulp may be chemically treated as needed, but chemical treatment is not mandatory, and untreated pulp is preferred. If chemical treatment is performed, it is preferable that the treatment does not significantly impair the degree of polymerization of the cellulose raw material. Chemical treatment may be performed at the time of grinding the cellulose raw material, or before the pretreatment for grinding.

[0032] [1.6 Optional Components] The absorbent material may contain components other than cellulose material. Examples include antioxidants, anti-aging agents, light stabilizers, heat stabilizers, ultraviolet absorbers, lubricants, anti-blocking agents, plasticizers, adhesives, inorganic fillers, reinforcing fibers such as glass fibers and carbon fibers, pigments, dyes, flame retardants, flame retardant additives, foaming agents, foaming additives, and antistatic agents.

[0033] [1.7 Dosage Form of Absorbent Material] The dosage form of the absorbent material is not particularly limited, but is usually solid, and examples include powder, granules, pellets, sheets, and films.

[0034] [2. Absorbent material and method of use thereof (method of processing aqueous composition containing organic matter)] Cellulose material is useful as an absorbent material for aqueous compositions because, by contacting it with an aqueous composition containing organic matter, it can absorb and retain liquid components and components dissolved, suspended, or dispersed in the liquid within the aqueous composition.

[0035] Examples of aqueous compositions containing organic matter include industrial wastewater, household wastewater, and agricultural wastewater. The destination of discharge is not particularly limited and can be, for example, factories (e.g., food processing plants, chemical plants, paper mills) or agricultural sites. Examples of organic matter include carbohydrates, proteins, lipids, and other components derived from plants and animals. Aqueous compositions containing organic matter may be liquid, or they may not be liquid but contain (retain) water within the substance, or water may have seeped out of the substance. Examples include vegetable and fruit residues and pulp, tea leaves, food residues and pulp, non-edible parts (residues) and waste from agricultural, marine, and livestock products, residues and pulp from processed marine products, residues and pulp from processed livestock products, residues and pulp from processed agricultural products (e.g., okara), waste from food distribution, and livestock manure.

[0036] The amount of organic matter in the aqueous composition containing organic matter is not particularly limited, but for example, it may be 20% by weight or less, 10% by weight or less, or 5% by weight or less, based on 100% by weight of the aqueous composition. The amount of water in the aqueous composition containing organic matter is not particularly limited, but for example, it may be 80% by weight or more, 90% by weight or more, or 95% by weight or more, based on 100% by weight of the aqueous composition. Even with a high water content, the water-containing components can be absorbed and stably retained, leaching is suppressed, and as a result absorption can be performed efficiently. There is no particular upper limit to the water content, and for example, it may be 99% by weight or less, 98% by weight or less, or 97% by weight or less. The amount of organic matter can be adjusted as needed by diluting the composition before treatment. The aqueous composition containing organic matter may also contain components other than organic matter (for example, inorganic substances).

[0037] The amount of cellulose material added to an organic-containing aqueous composition is usually 1% by weight or more, preferably 2% by weight or more, more preferably 3% by weight or more, and even more preferably 4% by weight or more, based on 100% by weight of the aqueous composition. The upper limit is not particularly limited, but is usually 70% by weight or less, preferably 60% by weight or less, and even more preferably 50% by weight or less. Therefore, for example, it is 1 to 70% by weight, preferably 2 to 60% by weight, more preferably 3 to 60% by weight, and even more preferably 4 to 50% by weight.

[0038] Absorption treatment typically involves contacting the object to be treated with an absorbent material. This allows for the absorption and retention of liquid components and components dissolved, suspended, or dispersed in the liquid (e.g., water-soluble components (which may be organic)) in the composition, and suppresses syneresis, thus eliminating the need for additional operations such as filtration. This also allows for the production of a solid with a higher solid content and lower fluidity in the aqueous composition. Contact can be carried out by mixing the absorbent material with the object to be treated (e.g., 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 1 hour or more; there is no particular upper limit, but for example, within 5 hours, within 4 hours, or within 3 hours). Other absorbent materials such as water absorbents, flocculants, and solidifying agents may be used in combination during contact, provided they do not interfere with the effects of the present invention, but it is preferable not to use them in combination. By not using them in combination, the treatment process can be simplified and costs can be reduced. Furthermore, contact can be carried out at room temperature (e.g., 10 to 35°C).

[0039] The absorbent material of the present invention can be used for the treatment of water-containing compositions containing organic matter, such as waste disposal, reuse, and recycling. Specifically, by reducing the moisture content, the water-containing composition as waste can be made lighter, making it easier to transport, combustible, and otherwise handle. Furthermore, the separated water can be reused or recycled through water purification treatment.

[0040] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples.

[0041] Table 1 shows the physical properties of the pulp used in the following tests. Each measurement in Table 1 was obtained using the method described above. All pulps had an ash content of 1.5% by weight or less.

[0042]

[0043] [Footnote of Table 1] *) Crushing treatment: It was crushed using a crusher (Recycling Finer, manufactured by Aikawa Iron Works Co., Ltd.) under the condition of a clearance of 0.15 to 3 mm. **) Manual crushing treatment: It was torn and crushed by hand.

[0044] Examples 1 to 3, Comparative Example 1 (Absorption test of grated daikon radish) Grated daikon radish was prepared by grating daikon radish with a grater. As shown in Table 2, a predetermined amount of each pulp was added to a predetermined amount of grated daikon radish (Examples 1 to 3), or without addition (Comparative Example 1), placed in a Buchner funnel installed in an Erlenmeyer flask, allowed to stand for 10 minutes, and then the recovered water collected in the Erlenmeyer flask was weighed. Also, the mixture before water separation was put into a dryer overnight, and the solid content was calculated (Table 2, Figures 1, 2).

[0045]

[0046] Compared with Comparative Example 1 where the recovered water exceeded 20 g and the solid content % was about 5%, in Examples 1 to 3, there was no or a trace amount of recovered water, and the solid content of the mixture exceeded 9.5%. The moisture content of the grated daikon radish was 94.1% based on the solid content % of Comparative Example 1. Therefore, it was found that by using pulp, a cake with improved solid content while suppressing the exudation of moisture from grated daikon radish can be produced.

[0047] Examples 4 to 7, Comparative Examples 2 to 3 (Absorption test 1 of mung bean sprouts) Mung bean sprouts were liquefied by putting them in a mixer (10 seconds, 22,000 rpm). As shown in Table 3, a predetermined amount of each pulp or sawdust was added to a predetermined amount of liquefied mung bean sprouts (Examples 4 to 7, Comparative Example 3), or without addition (Comparative Example 2), placed in a Buchner funnel installed in an Erlenmeyer flask, allowed to stand for 10 minutes, and then the recovered water collected in the Erlenmeyer flask was weighed. Also, the mixture before water separation was put into a dryer overnight, and the solid content was calculated (Table 3, Figures 1, 2).

[0048]

[0049] In Comparative Example 2, the recovered water was slightly less than 30 g and the solid content was 2.9%. In contrast to Comparative Example 3, which used sawdust, the recovered water exceeded 10 g. In Examples 4 to 6, the recovered water was only a small amount or 6 g or less, and the solid content of the mixture was 7.5% or more. In Comparative Example 2, it was confirmed that the mixture had high fluidity when the container containing the mixture was turned on its side, whereas in Example 7, almost no fluidity was observed (Figures 3 and 4). The moisture content of the bean sprouts was 97.1% based on the solid content percentage of Comparative Example 2. Therefore, it was found that by using pulp, it is possible to produce a cake with improved solid content while suppressing the seepage of moisture from liquefied bean sprouts, and the fluidity of the mixture after water absorption can be suppressed.

[0050] Examples 8-9, Comparative Example 4 (Absorption Test of Tea Leaves) As shown in Table 4, a predetermined amount of used tea leaves were placed in a Buchner funnel set up in an Erlenmeyer flask with a predetermined amount of each pulp (Examples 8-9), or without any addition (Comparative Example 3), and left to stand for 10 minutes. The recovered water accumulated in the Erlenmeyer flask was then measured. The pre-synthesized mixture was placed in a dryer overnight, and the solid content was calculated.

[0051]

[0052] Compared to Comparative Example 4, where the solid content was approximately 25%, the solid content of the mixtures in Examples 8 and 9 was 36.0% or higher. The moisture content of the used tea leaves was 74.5% based on the solid content percentage of Comparative Example 4. Therefore, it was found that using pulp can improve the solid content while suppressing moisture leaching from used tea leaves.

[0053] Examples 10 and Comparative Examples 5-6 (Bean Sprout Absorption Test 2) Bean sprouts (liquidated in the same way as in Example 4) or sawdust (the same as used in Comparative Example 3) were mixed with pulp in the ratios shown in Table 5 (Example 10, Comparative Example 6), or left unmixed (Comparative Example 5). 20 g of each mixture was placed in a 110 ml screw-top bottle and left to stand for 3 days. After that, the bottle was tilted on its side, and the degree of water separation was observed after 5 minutes (Figures 5-7).

[0054]

[0055] In Comparative Example 5, which contained no additives, a large amount of water was released, and in Comparative Example 6, which had sawdust added, some water was released. However, no water release was observed in Example 10, which had pulp added. Therefore, it was found that by using pulp, it is possible to improve the solid content while sufficiently suppressing water seepage, and that water seepage can be suppressed even after long-term storage.

[0056] The results of the above examples demonstrate that by using the absorbent material of the present invention, it is possible to absorb and retain organic matter in a liquid composition, suppress syneresis and seepage, improve the solid content, and produce a cake with low fluidity.

Claims

1. An absorbent material for a water-containing composition containing organic matter, comprising a cellulose material with a fiber length of 0.2 to 5 mm and a fiber width of 10 to 50 μm.

2. The absorbent material according to claim 1, wherein the cellulose material is pulp.

3. The absorbent material according to claim 2, wherein the pulp has a whiteness of 10 to 95%.

4. The absorbent material according to claim 2, wherein the solid content of the pulp is 15% or more.

5. The absorbent material according to claim 2, wherein the pulp is hardwood or softwood pulp.

6. The absorbent material according to any one of claims 2 to 5, wherein the pulp is kraft pulp.

7. A method for treating an organic-containing aqueous composition, comprising contacting the absorbent material described in any one of claims 1 to 5 with the aqueous composition, thereby allowing the absorbent material to absorb the water-containing components in the aqueous composition.

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