Water purifying agent, its manufacturing method, and water purifying method

Abstract

To provide: a water cleaning agent which can reduce segregation of a plant component and a polymer flocculant in a granulation product and exhibits excellent cleaning performance; a production method thereof; and a water cleaning method employing the water cleaning agent.SOLUTION: The water cleaning agent comprises a granulation product of a mixture containing a plant component and a polymer flocculant, where the degree of segregation of the plant component and the polymer flocculant after processing under prescribed conditions is 10% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a plant-derived water purifying agent used for purifying water such as industrial wastewater, a method for producing the same, and a water purification method using the water purifying agent. [Background technology]

[0002] BACKGROUND ART In recent years, a large amount of waste liquid containing inorganic ions such as metal ions and fluorine ions that cause environmental loads has been generated in the process of manufacturing various products in factories. On the other hand, regulations regarding the discharge of these inorganic ions are gradually becoming stricter. In order to comply with these discharge regulations, there is a need for a method for removing inorganic ions that can effectively remove inorganic ions from wastewater containing inorganic ions and that can be implemented as simply and inexpensively as possible. Conventionally, methods proposed for removing impurity ions from industrial wastewater and the like include coagulation sedimentation, ion exchange, adsorption onto adsorbents such as activated carbon, electrical adsorption, and magnetic adsorption.

[0003] For example, a coagulation and sedimentation method has been proposed, which includes the steps of adding a base to wastewater containing dissolved heavy metal ions to make the wastewater basic, thereby insolubilizing at least a portion of the heavy metal ions and forming suspended solids; adding an inorganic coagulant to the wastewater to coagulate and settle the suspended solids; adding a polymer coagulant to the wastewater to form giant flocs of the suspended solids; and passing the wastewater through an adsorption layer containing a cation exchanger made from leafy vegetables such as molokheiya or komatsuna (Japanese mustard spinach) (see, for example, Patent Document 1). In addition, a flocculation method has been proposed in which a flocculation agent containing at least one of molokheiya, its dried product, or its extract is mixed or used in combination with a polymer flocculating agent to flocculate and separate fine particles in a suspension (see, for example, Patent Document 2).

[0004] Furthermore, the larger the amount of wastewater to be purified, the greater the amount of unwanted substances contained in the wastewater, or the greater the variety of unwanted substances contained in the wastewater, the more desirable it is to build a system that automatically adds the purification agent necessary for purifying the wastewater. Therefore, a water purifying agent made of a granulated material containing a mixture of plant powder and a polymer flocculant has been proposed as a water purifying agent that can be suitably used in an automated purifying device (see, for example, Patent Document 3). In addition, a method for producing a water purifier that can be suitably used in automated purification equipment with large-scale drainage tanks, is low-cost, does not vary from one product to another, and exhibits stable purification performance has also been proposed (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-194385 [Patent Document 2] Japanese Patent Application Publication No. 11-114313 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-73898 [Patent Document 4] Japanese Patent Application Publication No. 2018-47451 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, various research and development efforts have been made on water purifying agents. However, the present inventors have newly discovered that the plant components and the polymer flocculant in the granulated product may separate during transportation of the water purifying agent, and that separation of the plant components and the polymer flocculant makes it impossible to obtain sufficient water purification performance.

[0007] The present invention aims to solve the above-mentioned problems of the prior art and to achieve the following objectives: That is, the present invention aims to provide a water purifying agent that can reduce separation of plant components and a polymer flocculant in a granulated product and exhibits excellent purification performance, a method for producing the same, and a water purification method using the water purifying agent. [Means for solving the problem]

[0008] As a result of extensive research, the inventors have found that a water purifying agent produced by a water purifying agent manufacturing method including a plant powder manufacturing process in which dried plants are crushed to obtain plant powder having a number average particle size of 250 μm or less, a granulation process in which the plant powder is mixed with a polymer coagulant, water is added, the mixture is pressurized and kneaded, and a granulation product is obtained by extrusion granulation, and a grinding process in which the granulation product is crushed to obtain a granular granulation product is less likely to separate from the plant components and polymer coagulant contained in the granulation product, and that excellent purification performance can be obtained when the degree of separation between the plant components and polymer coagulant after the water treatment agent is treated under specified conditions is 10% or less.

[0009] The means for solving the above problems are as follows: <1> The present invention is directed to a granulated mixture containing a plant component and a polymer flocculant, This water purifying agent is characterized in that the degree of separation between plant components and polymer flocculant after treatment under the sine wave sweep vibration test conditions (level 2) of JIS Z 0232 is 10% or less. <2> The mass ratio of the plant component to the polymer flocculant (plant component / polymer flocculant) is 0.1 / 99.9 to 99.9 / 0.1. <1> The water purifying agent according to claim 1. <3> The mass ratio of the plant component to the polymer flocculant (plant component / polymer flocculant) is 1 / 9 to 9 / 1. <2> The water purifying agent according to claim 1. <4> The plant of the plant component is at least one of jute and molokhiya. <1> from <3> The water purifying agent according to any one of the above items. <5> The polymer flocculant is polyacrylamide. <1> from <4> The water purifying agent according to any one of the above items. <6> The bulk density of the water purifying agent is 0.18 to 0.80 g / cm 3 The above <1> from <5> The water purifying agent according to any one of the above items. <7> The water purifying agent has a variation in bulk density (the ratio of the difference between the maximum and minimum bulk density values ​​to the minimum bulk density value) of less than 5%. <6> The water purifying agent according to claim 1. <8> The viscosity of a solution or dispersion obtained by dissolving or dispersing 0.1 parts by mass of the water purifying agent in 100 parts by mass of pure water at 23°C is 100 to 350 mPa·s. <1> from <7> The water purifying agent according to any one of the above items. <9> The aforementioned <1> from <8> A method for producing a water purifying agent according to any one of the above, a plant powder manufacturing process in which a dried plant is pulverized to obtain a plant powder having a number average particle size of 250 μm or less; A granulation step of mixing the plant powder and a polymer flocculant, adding water, kneading under pressure, and extruding the mixture to obtain a granulated product; and a crushing step of crushing the granulated product to obtain a granular product. <10> The aforementioned <1> from <8> The water purifying agent according to any one of the preceding claims and <9> a water purification method comprising dissolving or dispersing in water any of the water purification agents obtained by the method for producing a water purification agent described in the above item 1 to obtain a solution or dispersion of a plant component and a polymer flocculant, and then subjecting the solution or dispersion to wastewater to remove inorganic unwanted substances from the wastewater. [Effects of the Invention]

[0010] According to the present invention, the above-mentioned problems of the prior art can be solved, the above-mentioned objectives can be achieved, and separation of plant components and polymer flocculants in the granulated product can be reduced, and a water purifying agent exhibiting excellent purification performance, a method for producing the same, and a water purification method using the water purifying agent can be provided. [Brief explanation of the drawings]

[0011] [Figure 1A] FIG. 1A shows an example of a water purification agent in which the degree of separation between the plant components and the polymer flocculant is 5% or less, and is a cropped image with the saturation set to 0. [Figure 1B] FIG. 1B is a brightness-corrected version of FIG. 1A. [Figure 1C] FIG. 1C is a black and white binarized version of FIG. 1B. [Figure 2A]FIG. 2A shows an example of a water purification agent in which the degree of separation between the plant components and the polymer flocculant exceeds 10%, and is a cropped image with the saturation set to 0. [Figure 2B] FIG. 2B is a brightness-corrected version of FIG. 2A. [Figure 2C] FIG. 2C is a black and white binarized version of FIG. 2B. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Water purifier) The water purification agent of the present invention comprises a granulated mixture containing at least plant components and a polymer flocculant, and optionally further containing other components, and the degree of separation between the plant components and the polymer flocculant after treatment under specified conditions is 10% or less. In the present invention, "water purification" refers to the removal of unwanted substances such as nickel, copper, and fluorine from industrial wastewater, particularly inorganic industrial wastewater. When the water purifying agent is added to the wastewater, the inorganic waste materials in the wastewater are coagulated and separated by the water purifying agent. When the coagulated materials are removed from the wastewater, the wastewater is purified.

[0013] <Granulation> The granulated product (hereinafter sometimes referred to as "particles") is a granulated product of a mixture containing at least a plant component and a polymer flocculant, and may further contain other components as required. By using a water purifier that is a granulated mixture containing plant powder and a polymer flocculant, it is possible to stably and repeatedly supply water purifier with the desired performance in an automated purification device with high accuracy.

[0014] -Plant ingredients- The plant from which the plant component (hereinafter sometimes referred to as "plant powder") is derived is not particularly limited as long as it is a plant that can coagulate and separate unwanted substances (nickel, copper, fluorine, etc.) in wastewater, and can be appropriately selected depending on the purpose, such as jute, molokheiya, komatsuna, mitsuba, mizuna, spinach, etc. These may be used alone or in combination of two or more. Among the above plants, at least one of jute and molokhiya is preferred, and jute is more preferred. The part of the plant is not particularly limited, and any part can be used, such as leaves, stems, roots, etc. These may be used alone or in combination of two or more. The content of the plant component in the water purifying agent is not particularly limited and can be appropriately selected depending on the purpose.

[0015] -Polymer flocculant- The polymer flocculant is not particularly limited as long as it is effective in removing unwanted substances (nickel, copper, fluorine, etc.) from wastewater, as with the plant components, and can be appropriately selected depending on the purpose, and examples thereof include polyacrylamide (PAM), partially hydrolyzed salts of polyacrylamide, sodium alginate, sodium polyacrylate, CMC (carboxymethylcellulose) sodium salt, etc. These may be used alone or in combination of two or more. Among the polymer flocculants, polyacrylamide is preferred, and examples of the polyacrylamide that can be used include commercially available products such as Flopam AN 905, Flopam AN 926, and Flopam AN 956 (manufactured by SNF Co., Ltd.). The content of the polymer flocculant in the water purifying agent is not particularly limited and can be appropriately selected depending on the purpose.

[0016] The mass ratio of the plant components to the polymer flocculant in the water purifying agent (plant components / polymer flocculant) (sometimes referred to as "the content ratio of the plant components to the polymer flocculant in the water purifying agent") is not particularly limited and can be selected appropriately depending on the type of wastewater to be purified, but is preferably 0.1 / 99.9 to 99.9 / 0.1, more preferably 1 / 9 to 10 / 1, even more preferably 1 / 9 to 9 / 1, and particularly preferably 1 / 10 to 8 / 2.

[0017] -Other ingredients- The other components are not particularly limited as long as they do not impair the effects of the present invention and can be appropriately selected depending on the purpose, and examples thereof include fillers, thickeners, colorants, thixotropy-imparting agents, etc. Furthermore, a small amount of liquid such as alcohol may be added for the purpose of improving the solubility of the kneading components in water. The other components may be added when the polymer flocculant is kneaded, or may be added when the plant component and the polymer flocculant are kneaded. The content of the other components in the water purifying agent is not particularly limited and can be appropriately selected depending on the purpose.

[0018] The shape (diameter, length) of the granules is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of widely adapting to the size of the supply port of commercially available metering machines, the diameter and length of the granules are preferably 3 mm or less. Furthermore, in order to ensure smooth passage through the supply port and also taking into consideration the solubility during dissolution, the diameter and length of the granules are more preferably 1 mm or less.

[0019] <Degree of separation between plant components and polymer flocculant> If the binding strength between the plant components and the polymer flocculant in the water purification agent is insufficient, separation between the materials occurs due to vibrations during transportation, etc. If separation occurs between the materials during transportation due to differences in specific gravity, etc., problems such as incorrect quantitative distribution in automatic feeders and incorrect blending ratios during dissolution occur. As a result, sufficient purification performance cannot be obtained.

[0020] The water purifying agent of the present invention has a degree of separation between plant components and polymer flocculant of 10% or less after treatment under the sine wave sweep vibration test conditions (level 2) of JIS Z 0232. The vibration test can be carried out under the following conditions. [conditions] Exam duration: 90 minutes · Acceleration: 7m / s Frequency range: 3~100Hz Sweep speed: 1 / 2 octave / min Under the above conditions, approximately 300 g of sample is placed in a cylindrical 2 L plastic container, the lid is put on, and vibration is applied while the container is placed upright.

[0021] The degree of separation of the plant components and the polymer flocculant in the water purifying agent can be measured by image analysis using a stereomicroscope as follows. (1) Take a photograph of the target sample using a stereo microscope (the image is 256-color RGB data). (2) Crop the captured image to a size of 2mm x 3mm. (3) Set the saturation of the cropped image to 0. (4) The brightness is corrected using the following formula from the average brightness of the image with saturation set to 0. Brightness correction (%) = average brightness × (-0.11)-6.5 (5) Set the contrast to 100% and convert to black and white. (6) The proportion of white areas in the binarized image is measured, and the degree of separation between the plant components and the polymer flocculant in the image is determined. (7) Take three images of the same sample, measure the data for three times using the above measurement method, and use the average value as the degree of separation between the plant components and the polymer flocculant in that sample.

[0022] The degree of separation between the plant components and the polymer flocculant in the water purification agent is not particularly limited as long as it is 10% or less and can be selected appropriately depending on the purpose, but 5% or less is preferred in terms of better water purification performance.

[0023] The bulk density of the water purifying agent is not particularly limited and can be appropriately selected depending on the purpose. 3 Furthermore, in an automated system, the time and power required for quantitative determination can be reduced, and the bulk density is preferably 0.4 g / cm3, which allows effective application to an automated purification device. 3 The median value (sometimes referred to as the center value) of the bulk density of the water purifying agent is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.45 g / cm or more. 3 The above median bulk specific gravity is the median value when five samples are measured.

[0024] The bulk density can be determined as follows. The bulk density can be measured using a powder tester PT-N type (manufactured by Hosokawa Micron Corporation). 100cc of the sample is gently placed in a 100cc stainless steel cup, and the specific gravity of the sample at that time is measured and used as the bulk specific gravity.

[0025] The variation in bulk density of the water purifying agent (the ratio of the difference between the maximum and minimum bulk density values ​​to the minimum bulk density value) is not particularly limited and can be appropriately selected depending on the purpose, but is preferably less than 5%, more preferably 4.5% or less. Within this preferred range, an automated system can repeatedly and accurately supply a water purifying agent with little fluctuation in blending ratio and consistent water purification performance, thereby enabling effective application to an automated purification device.

[0026] The variation in bulk density can be determined as follows. The water purifying agent to be measured is placed in a bag of a certain size (for example, a 700 mm × 500 mm plastic bag), and the opening of the bag is heat-sealed. The amount of water purifying agent placed in the bag is considered so that sufficient space is secured for the water purifying agent to move freely in the subsequent vibration operation. Next, the water purifying agent placed in the bag is vibrated up and down to the extent that the granules do not crumble. Then, samples are taken from five points, including the top and bottom of the bag, and the bulk density of each is measured. The maximum and minimum values ​​of the bulk specific gravity are recorded, and the variation is calculated based on these maximum and minimum values ​​using the following calculation. Bulk density variation (%) = (difference between maximum and minimum bulk density / minimum bulk density) x 100

[0027] The viscosity at 23°C of a solution or dispersion obtained by dissolving or dispersing 0.1 parts by mass of the water purifying agent in 100 parts by mass of pure water is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 100 to 350 mPa·s. The median viscosity (sometimes referred to as the center value) is also not particularly limited and can be selected appropriately depending on the purpose, but is preferably 200 mPa·s or higher. The median viscosity refers to the median value when five samples are measured.

[0028] The method for producing the water purifying agent is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable to produce it by the method for producing a water purifying agent of the present invention described below.

[0029] The water purifying agent of the present invention can reduce separation of the plant components and the polymer flocculant in the granules even when vibrations occur during transportation, etc., and exhibits excellent water purification performance. Furthermore, the water purifying agent of the present invention can be supplied in a fixed amount by an automatic supply machine, and sedimentation or precipitation in the dissolution or dispersion tank is suppressed, so that problems such as accumulation in piping do not occur. The water purifier of the present invention can be suitably used in an automated purification device that can stably and repeatedly supply a water purifier with the desired performance at low cost when purifying wastewater using the water purifier using the automated purification device.

[0030] (Water Purification Agent Manufacturing Method) The method for producing a water purifying agent of the present invention includes at least a plant powder production step, a granulation step, and a pulverization step, and may further include other steps such as a drying step and a classification step, as necessary.

[0031] <Plant powder manufacturing process> The plant powder production step is a step of pulverizing a dried plant to obtain a plant powder having a number average particle size of 250 μm or less. The method for preparing the dried plant is not particularly limited and can be appropriately selected depending on the purpose. For example, a method of drying a plant in the sun or using a dryer until the moisture content is 5% or less can be used. The type of dried plant is not particularly limited and can be appropriately selected depending on the purpose. Examples include the same plants as those described above in the section on plant components of water purifying agents.

[0032] The method for pulverizing the dried plant is not particularly limited, and any known pulverizer can be appropriately selected. For example, an atomizer (hammer mill, manufactured by Dalton) can be used to pulverize the plant to a number average particle size of 250 μm or less. Here, the number average particle size can be measured using, for example, Morphologi G3 (manufactured by Malvern Instruments).

[0033] <Granulation process> The granulation step is a step of mixing the plant powder and the polymer flocculant, adding water, kneading under pressure, and extruding the mixture to obtain a granulated product. In the granulation step, other components may be added as needed in addition to the plant powder and the polymer flocculant.

[0034] The polymer flocculant is not particularly limited and can be appropriately selected depending on the purpose. For example, the same polymer flocculant as those described in the section on polymer flocculants for water purification agents above can be used. The size of the polymer flocculant is not particularly limited as long as it is equal to or smaller than the size of the granules, and can be appropriately selected depending on the purpose. For example, if a commercially available polymer flocculant is equal to or smaller than the size of the granules, it can be used as is. If the polymer flocculant is larger than the size of the granules, it can be pulverized to the desired size using a pulverizer such as an atomizer (hammer mill, manufactured by Dalton).

[0035] The plant powder obtained above is mixed with the polymer flocculant, and water is added thereto, followed by kneading under pressure. The mixing ratio of the plant powder and the polymer flocculant is not particularly limited and can be selected appropriately depending on the purpose, and can be, for example, the same as that described in the water purification agent section above.

[0036] The amount of water added (hereinafter sometimes referred to as "kneading water amount") is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 15 to 250 mass% of water, more preferably 50 to 200 mass%, and particularly preferably 100 to 200 mass% of water relative to the total mass of solids. The total mass of solids refers to the total mass of the plant powder and polymer flocculant, but if other components (for example, those listed in the section on other components of the water purifying agent above) are contained in addition to the plant powder and polymer flocculant, it refers to the sum of all solid components including the other components. As a guideline for the amount of water to be added during kneading, since the polymer flocculant absorbs a lot of water, the higher the mixing ratio of the polymer flocculant, the more water should be added. For example, for a mixture where the mass ratio (plant powder / polymer flocculant) is 9 / 1, 15% by mass of water should be added relative to the total mass of the mixture; for a mixture where the mass ratio is 3 / 1, 20% by mass of water should be added; and for a mixture where the mass ratio is 1 / 10, 50% by mass of water should be added.

[0037] After kneading under pressure, the wet mass of the kneaded product is extruded from the granulator through small holes into a cylindrical shape to obtain granules (sometimes referred to as "pellet-shaped granules"). The pressure kneading / granulation device is not particularly limited, and a commercially available kneading device can be used, for example, a pressure kneader. The pressurized kneading time is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 to 60 minutes, more preferably 10 to 60 minutes. The rotation speed during granulation is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 to 90 rpm, more preferably 5 to 15 rpm, and particularly preferably 10 rpm. The pressure during granulation is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 20 to 40 MPa, and particularly preferably 30 MPa.

[0038] The size of the pellet-shaped granulated product is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 3 mm or less in diameter and 3 to 10 mm in length.

[0039] <Drying process> The granulation step may be followed by a drying step, in which the pellet-shaped granules can be dried in a fluidized bed dryer or the like until the moisture content reaches about 5 to 15%.

[0040] <Crushing process> The pulverization step is a step of pulverizing the granulated material to obtain a granular granulated material. A known grinder can be used for the grinding. The diameter of the granulated product is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 mm or less.

[0041] <Drying process> After the pulverization step, a drying step may be carried out, in which the granulated material is dried in a fluidized bed dryer or the like until the moisture content is 5% or less.

[0042] <Classification process> After the pulverization step, a classification step is preferably carried out. The classification can be carried out using a known device such as a vibrating screen classifier. In the classification step, it is preferable to classify the granulated product so that the particle size falls within a predetermined range, so that the median size falls within the range of 150 to 900 μm.

[0043] <Other processes> The other steps are not particularly limited as long as they do not impair the effects of the present invention, and can be appropriately selected depending on the purpose. Examples thereof include the drying step and classification step described above.

[0044] According to the method for producing a water purifying agent of the present invention, it is possible to stably produce a water purifying agent in which separation of the plant components and the polymer flocculant in the granulated material is suppressed even when vibrations such as those caused by transportation occur. Furthermore, according to the method for producing a water purifying agent of the present invention, it is possible to produce a water purifying agent in which the bulk density value of the water purifying agent and the viscosity of the dispersion or solution can be controlled, compared to conventional production methods. Furthermore, according to the method for producing a water purifying agent of the present invention, the shear force on plants is reduced, so that the water purifying agent that has become too fine in the classification step can be reused when mixing again. Furthermore, the method for producing a water purifying agent of the present invention can improve the yield to about 85% or more, and can also improve mass productivity, reduce costs, and improve quality stability.

[0045] (Water purification method) The water purification method of the present invention (sometimes referred to as a wastewater treatment method) involves dissolving or dispersing either the water purifying agent of the present invention or the water purifying agent obtained by the production method of the present invention in water to obtain a solution or dispersion of plant components and a polymer flocculant, and then subjecting the solution or dispersion to wastewater to remove inorganic waste materials from the wastewater.

[0046] Examples of the inorganic waste include inorganic waste containing at least one of nickel, fluorine, iron, copper, zinc, chromium, arsenic, cadmium, and lead.

[0047] The water used in the dissolution or dispersion is not particularly limited and can be appropriately selected depending on the purpose. Examples include pure water (distilled water) and water with an electrical conductivity of 30 μS / cm or more.

[0048] An example of the water purification method will be described below. The water purifying agent is measured by a meter and then fed to a dissolving tank. The water purifying agent is dissolved or dispersed in a predetermined amount of water, and the resulting solution or dispersion is sent to a reaction tank and used as wastewater. In the reaction tank, inorganic waste materials (e.g., nickel, copper, fluorine, etc.) in the wastewater are coagulated and separated by the plant powder and polymer coagulant. The wastewater is purified by removing the coagulated materials. [Example]

[0049] The present invention will be explained in more detail below by way of test examples, but the present invention is not limited to these.

[0050] (Test Example 1: Comparison of water purifiers manufactured using different methods) Example 1 Chinese jute was sun-dried until the moisture content was 5% or less. Next, the dried plant was pulverized in a pulverizer until the number average particle size was 250 μm or less to obtain a plant powder. The plant powder was mixed with a polymer flocculant (polyacrylamide powder (Flopam AN 956, manufactured by SNF Co., Ltd.)) so that the mass ratio (plant powder / polymer flocculant) of the two was 1 / 1, and 50% by mass of water was added to the total mass of the mixture and kneaded. The mixture was kneaded using a pressure kneader. This kneaded mixture was continuously extruded into a cylindrical shape with a diameter of 3 mm using an extruder and granulated into pellets. This granulated material was dried in a fluidized bed dryer until the moisture content was approximately 5%, then pulverized in a grinder and classified (150 to 900 μm) in a vibrating screen classifier to obtain the granulated material (water purifying agent of Example 1).

[0051] -evaluation- The following evaluations were carried out.

[0052] [Appearance of granulated material before classification] The appearance of approximately 100 g of the granules before classification was evaluated according to the following criteria. The results are shown in Table 1. -Evaluation criteria- ○: Most of the particles are not attached (separate). △: Some particles are extremely large or some particles are stuck together. ×: More than half of the particles are extremely large or the particles are stuck together.

[0053] [Classification yield] The classification yield (%) in the production of the granules was calculated using the following formula and evaluated according to the following criteria. The results are shown in Table 1. Classification yield (%) = (150-900 μm classification amount (weight) / granulation amount (weight) when fed into classifier) ​​× 100 -Evaluation criteria- ○: Classification yield is 80% or more △: Classification yield is 70% or more but less than 80% ×: Classification yield is less than 70%

[0054] [Sedimentation resistance, viscosity of solution or dispersion] -Wastewater used for experiments- For the wastewater used in the experiment, nickel sulfate hexahydrate was dissolved in pure water to prepare 800 g of an aqueous solution containing 50 mg / L of nickel ions (virtual wastewater). Next, caustic soda was added to the wastewater to adjust the pH to 10, and the mixture was stirred to insolubilize the nickel. The nickel ion concentration in the supernatant of the wastewater was 2 mg / L.

[0055] -Dissolution or dispersion- Water (tap water from Kanuma City, Tochigi Prefecture) with an electric conductivity of 111 (μS / cm) was added to the granules so that the solid content was 0.1% by mass, and the mixture was stirred to obtain a solution or dispersion. The viscosity of the solution or dispersion was measured using a Brookfield viscometer. The viscosity was measured using a TVC-7 viscometer (B-type viscometer) manufactured by Toki Sangyo Co., Ltd., at room temperature of 23°C using a No. 1 rotor. The viscosity of the solution or dispersion was evaluated according to the following evaluation criteria. The results are shown in Table 1. --Evaluation criteria-- ◎: Median viscosity is 200 mPa·s or more ○: Median viscosity is 100 mPa·s or more and less than 200 mPa·s ×: Median viscosity is less than 100 mPa·s

[0056] The solution or dispersion containing the granulated product was added to the wastewater so that the solid content was 7 mg / L, and the mixture was stirred. Here, the "solid content" can be determined by measuring the slurry concentration in the wastewater with a moisture meter and then calculating backward. The wastewater to which the solution or dispersion liquid had been added was transferred to a settling tank, and then allowed to stand, and the state was visually checked every hour. The time when it was confirmed that the supernatant liquid and the precipitate had clearly separated into two layers was measured as the settling time. The settling resistance was evaluated according to the following criteria. The results are shown in Table 1. --Evaluation criteria-- ◎: Settling time is 120 hours or more. ○: Settling time is 72 hours or more but less than 120 hours. ×: Settling time is less than 72 hours.

[0057] [Bulk density, bulk density variation] The granulated product was subjected to the following measurements to determine the bulk density (maximum value, minimum value) and the variation in bulk density. -Bulk density- The bulk density was measured using a powder tester PT-N type (manufactured by Hosokawa Micron Corporation). 100 cc of the sample was gently placed in a 100 cc stainless steel cup, and the specific gravity of the sample was measured at that time to determine the bulk specific gravity. The bulk specific gravity was evaluated according to the following evaluation criteria. The results are shown in Table 1. --Evaluation criteria-- ◎: Median bulk density is 0.45g / cm 3 End ○: Median bulk density is 0.35 g / cm 3 More than 0.45g / cm 3 less than ×: Median bulk density is 0.35 g / cm 3 less than

[0058] -Bulk density variation- The variation in bulk density was measured by placing the granulated material to be measured as a sample in a bag of a certain size (a 700 mm × 500 mm plastic bag), heat-sealing the opening of the bag, and then vibrating the granulated material in the bag up and down. After that, samples were taken out from five points including the top and bottom of the bag, and the bulk density of each was measured. The maximum and minimum values ​​of bulk density were recorded, and the variation in bulk density was calculated based on these maximum and minimum values ​​using the following formula. The variation in bulk density was evaluated using the following evaluation criteria. The results are shown in Table 1. The variation in bulk density was evaluated from the perspective of whether a water purifying agent with consistent water purification performance can be repeatedly and accurately supplied, and the effectiveness of application to an automated purification device was evaluated. Bulk density variation (%) = (difference between maximum and minimum bulk density / minimum bulk density) x 100 --Evaluation criteria-- ◎: Variation in bulk density is less than 5% ○: Variation in bulk density is 5% or more but less than 10% ×: Variation in bulk density is 10% or more

[0059] The bulk density of long-saku jute powder is 0.15g / cm 3 The bulk density of the polymer flocculant is 0.75 g / cm 3 The bulk density of the granulated product of Example 1, which is a mixture of these, is 0.18 to 0.80 g / cm, as shown in Table 1 below. 3 That was about it. The water purifying agent of the present invention is a granulated mixture containing a plant component and a polymer flocculant, and therefore the bulk density can be controlled as desired.

[0060] [Material yield] The material yield (%) in the production of the granules was calculated using the following formula and evaluated according to the following criteria. The results are shown in Table 1. Material yield (%) = (weight of granulated material after classification / total weight of polymer flocculant and plant powder used in production) x 100 -Evaluation criteria- ◎: Median material yield is 80% or more ○: Median material yield is between 75% and 80% △: Median material yield is 70% or more but less than 75% ×: Median material yield is less than 70%

[0061] [Separation resistance] The binding property (separation resistance) between the plant component and the polymer flocculant of the granulated product was evaluated as follows.

[0062] -Transportation vibration test- The granules were subjected to the following transport vibration test. Specifically, the test was carried out under the following conditions as the sine wave sweep vibration test conditions (level 2) of JIS Z 0232. [conditions] Exam duration: 90 minutes · Acceleration: 7m / s Frequency range: 3~100Hz Sweep speed: 1 / 2 octave / min Under the above conditions, approximately 300 g of the sample was placed in a cylindrical 2 L plastic container, which was then covered and placed upright and subjected to vibration.

[0063] -Image analysis- Separation of the plant components and polymer flocculant means that the polymer flocculant and the plant are present alone after separation. Therefore, in the case of the polymer flocculant alone, the degree of separation can be calculated by using its whiteness and determining the area of ​​the white part through image analysis. Therefore, the degree of separation of the plant components and the polymer flocculant in the water purifying agent after the vibration test was measured by image analysis using a stereomicroscope as follows. (1) The target sample was photographed using a stereo microscope (images were 256-color RGB data). (2) A portion of the captured image was cropped to a size equivalent to 2 mm x 3 mm. (3) The saturation of the cropped image was set to 0. (4) The brightness was corrected using the following formula from the average brightness of the image with saturation set to 0. Brightness correction (%) = average brightness × (-0.11)-6.5 (5) The contrast was set to 100% and the image was binarized to black and white. (6) The proportion of white areas in the binarized image was measured, and the degree of separation between the plant components and the polymer flocculant in the image was determined. (7) Three images were taken from the same sample, and the data for three runs was measured using the above measurement method. The average value was used as the degree of separation between the plant components and the polymer flocculant in that sample.

[0064] The degree of separation between the plant components and the polymer flocculant obtained by the image analysis was evaluated according to the following criteria. The results are shown in Table 1. - Evaluation criteria for the degree of separation (separation resistance) between plant components and polymer flocculants in water purification agents - ◎: The degree of separation between the plant components of the water purification agent and the polymer flocculant is 5% or less ○: The degree of separation between the plant components and polymer flocculant in the water purification agent is more than 5% and 10% or less ×: The degree of separation between the plant components of the water purification agent and the polymer flocculant is more than 10%. As an example of a water purification agent with a separation degree of 5% or less between the plant components and the polymer flocculant, Figures 1A-1C show a separation degree of 3.2%. Figure 1A is a cropped image with the saturation set to 0, Figure 1B is Figure 1A with brightness corrected, and Figure 1C is Figure 1B binarized into black and white. As an example of a water purification agent with a separation degree of more than 10% between the plant components and the polymer flocculant, Figures 2A-2C show a separation degree of 17.9%. Figure 2A is a cropped image with the saturation set to 0, Figure 2B is Figure 2A with brightness corrected, and Figure 2C is Figure 2B binarized into black and white.

[0065] [Mass productivity] The mass productivity of Example 1 was evaluated according to the following evaluation criteria. The results are shown in Table 1. -Evaluation criteria- ◎: The production volume of water purification agent is 20 kg / hour or more. ○: The production volume of water purification agent is 10 kg / hour or more but less than 20 kg / hour. △: The production volume of water purification agent is less than 10 kg / hour.

[0066] <Comparative Example 1> In the same manner as in Example 1, a plant powder of jute was obtained. The plant powder and a polymer flocculant (polyacrylamide powder (Flopam AN 956, manufactured by SNF Co., Ltd.)) were mixed in a mass ratio (plant powder / polymer flocculant) of 1 / 1, and 60 mass% of water was added to the total mass of the mixture, which was then kneaded and granulated using an agitation granulation method. A granulated product (water purification agent of Comparative Example 1) was obtained in the same manner as in Example 1. The granules were evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0067] <Comparative Example 2> In the same manner as in Example 1, a plant powder of jute was obtained. The plant powder and a polymer flocculant (polyacrylamide powder (Flopam AN 956, manufactured by SNF Co., Ltd.)) were mixed in a mass ratio (plant powder / polymer flocculant) of 1 / 1, and 70 mass% of water was added to the total mass of the mixture, which was then kneaded and granulated using a sheet granulation method. A granulated product (water purification agent of Comparative Example 2) was obtained in the same manner as in Example 1. The granules were evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0068] [Table 1]

[0069] As shown in Table 1, Example 1 had a wide and satisfactory control range for each property. On the other hand, Comparative Example 1 had poor properties in terms of separation resistance and bulk density, and unsatisfactory results were not obtained. Furthermore, Comparative Example 2, which used a sheet granulation method, also had good properties, but unsatisfactory results were not obtained in terms of yield.

[0070] (Test Example 2) <Production of water purifying agents of Examples 2 to 12 and Comparative Examples 3 to 12> In the same manner as in Example 1, a plant powder of jute was obtained. The plant powder and a polymer flocculant (polyacrylamide powder (Flopam AN 956, manufactured by SNF Corporation)) were mixed so that the mass ratio (plant powder / polymer flocculant) of the two was the mass ratio shown in Tables 2-1 to 3-2 below, and water was added to the mixture in the amounts shown in Tables 2-1 to 3-2 below based on the total mass, and the mixture was kneaded. The kneaded mixture was kneaded using a pressure kneader for the kneading time, rotation speed during granulation, and pressure during granulation as shown in Tables 2-1 to 3-2 below. This kneaded mixture was continuously extruded into a cylindrical shape with a diameter of 3 mm using an extruder and granulated into pellets. This granulated material was dried in a fluidized bed dryer until the moisture content was approximately 5%, then pulverized in a grinder and classified (150 to 900 μm) in a vibrating screen classifier to obtain granulated materials (water purifying agents of Examples 2 to 12 and Comparative Examples 3 to 12).

[0071] <Evaluation> [Degree of separation between plant components and polymer flocculant (separation resistance)] The separation resistance of the granulated products obtained in Examples 2 to 12 and Comparative Examples 3 to 12 was evaluated in the same manner as in Test Example 1. The results are shown in the following Tables 2-1 to 3-2.

[0072] [Water purification performance (including viscosity and sedimentation time measurements)] -Wastewater used for experiments- For the wastewater used in the experiment, nickel sulfate hexahydrate was dissolved in pure water to prepare 800 g of an aqueous solution containing 50 mg / L of nickel ions (virtual wastewater). Next, caustic soda was added to the wastewater to adjust the pH to 10, and the mixture was stirred to insolubilize the nickel. The nickel ion concentration in the supernatant of the wastewater was 2 mg / L.

[0073] -Dissolution or dispersion- Water (tap water from Kanuma City, Tochigi Prefecture) having an electrical conductivity shown in Tables 2-1 to 3-2 below was added to the granulated products obtained in Examples 2 to 12 and Comparative Examples 3 to 12 so that the solid content was 0.1% by mass, and the mixture was stirred to obtain a solution or dispersion. The viscosity of the solution or dispersion was measured using a B-type viscometer. The viscosity was measured using a TVC-7 viscometer (B-type viscometer) manufactured by Toki Sangyo Co., Ltd., at room temperature of 23°C using a No. 1 rotor. The results are shown in Tables 2-1 to 3-2 below.

[0074] -evaluation- A solution or dispersion containing a water purification agent was added to the wastewater so that the solid content was 7 mg / L, and the mixture was stirred. Here, the "solid content" can be determined by measuring the slurry concentration in the wastewater with a moisture meter and then calculating backward. The wastewater to which the solution or dispersion liquid had been added was transferred to a settling tank, and then allowed to stand, and the state was visually checked every hour. The time when it was confirmed that the supernatant and the precipitate had clearly separated into two layers was measured as the sedimentation time. The results are shown in Tables 2-1 to 3-2 below. The supernatant was also collected, and the nickel ion concentration was measured using a DR3900 absorptiometer (manufactured by HACH), and the water purification performance was evaluated according to the following criteria. The results are shown in Tables 2-1 to 3-2 below. [Evaluation criteria for water purification performance] ◎: Nickel ion concentration is 0.3 mg / L or less ○: Nickel ion concentration is over 0.3 mg / L and 0.8 mg / L or less △: Nickel ion concentration is over 0.8 mg / L and 1.0 mg / L or less ×: Nickel ion concentration is over 1.0 mg / L

[0075] [Table 2-1]

[0076] [Table 2-2]

[0077] [Table 3-1]

[0078] [Table 3-2]

[0079] As shown in Tables 2-1 to 3-2, Examples 2 to 12, in which the degree of separation between the plant components and the polymer flocculant after treatment under specified conditions was 10% or less, all exhibited excellent water purification performance due to the synergistic effect of the integration of the plant components and the polymer flocculant, and were all good. Examples 2 to 4, in which the mass ratio of the plant components to the polymer flocculant was changed, all had good properties. In addition, Example 5, in which the amount of water added during kneading was 50%, and Example 6, in which the amount of water added during kneading was 200%, also had good properties. In addition, Examples 7 to 12, in which any of the kneading time, granulation rotation speed, and granulation pressure was changed, also had good properties. On the other hand, in Comparative Examples 3 to 12, where the degree of separation between the plant components and the polymer flocculant after treatment under the specified conditions was greater than 10%, the synergistic effect between the plant components and the polymer flocculant was not obtained, and all of the water purification performances were poor. Furthermore, Comparative Example 3, which had a high proportion of polymer flocculant components, and Comparative Example 4, which had an extremely high proportion of plant components, had poor viscosity characteristics and did not produce satisfactory results.

[0080] From the above results, it was confirmed that the present invention suppresses separation of plant components and polymer flocculant in the water purifying agent, and exhibits excellent water purification performance.

Claims

1. A water purifying agent comprising a granulated mixture containing a plant component and a polymer flocculant, The plant of the plant component is at least one of jute and molokhiya, the mass ratio of the plant component to the polymer flocculant (plant component / polymer flocculant) is 1 / 9 to 10 / 1; the degree of separation between the plant components and the polymer flocculant after treating the water purification agent under the sine wave sweep vibration test conditions (level 2) of JIS Z 0232 is 10% or less; The water purifying agent has a median bulk specific gravity of 0.45 g / cm 3 or more.

2. A water purification agent as described in claim 1, wherein the polymer flocculant is polyacrylamide.

3. The water purifying agent according to claim 1, wherein the bulk specific gravity of the water purifying agent is 0.18 to 0.80 g / cm 3 .

4. A water purifier described in any of claims 1 to 3, wherein the variation in bulk density of the water purifier (the ratio of the difference between the maximum and minimum bulk density values ​​to the minimum bulk density value) is less than 5%.

5. A water purifying agent described in any one of claims 1 to 4, wherein the viscosity of a solution or dispersion obtained by dissolving or dispersing 0.1 parts by mass of the water purifying agent in 100 parts by mass of pure water at 23°C is 100 to 350 mPa·s.

6. A method for producing a water purifying agent according to any one of claims 1 to 5, a plant powder production step of pulverizing a dried plant to obtain a plant powder having a number average particle size of 250 μm or less; A granulation step of mixing the plant powder and a polymer flocculant, adding water, kneading under pressure, and extruding the mixture to obtain a granulated product; and a grinding step of grinding the granulated material to form a granular material.

7. A method for producing a water purifying agent as described in Claim 6, wherein the pressurized kneading time in the granulation process is 10 to 60 minutes.

8. A method for producing a water purifying agent described in any one of claims 6 to 7, wherein the rotation speed during granulation in the granulation process is 5 to 15 rpm.

9. A method for producing a water purifying agent described in any one of claims 6 to 8, wherein the pressure during granulation in the granulation process is 20 to 40 MPa.

10. A water purification method comprising dissolving or dispersing in water either the water purifying agent according to any one of claims 1 to 5 or the water purifying agent obtained by the method for producing a water purifying agent according to any one of claims 6 to 9, obtaining a solution or dispersion of plant components and a polymer flocculant, and subjecting the solution or dispersion to wastewater, thereby removing inorganic unwanted substances from the wastewater.

Images