JP6096454B2 - Method for producing activated carbon composite material - Google Patents

Description

The present invention relates to a method for manufacturing activated carbon composite material, in particular, include activated carbon composite material formed by growing an inorganic crystal having an adsorption function and the like on the surface of activated carbon, and a manufacturing method therefor, and more activated carbon composite material It relates to a filter body.

  Activated carbon can adsorb various molecules due to its developed porosity. Moreover, since the raw materials themselves are inexpensive, they are widely used regardless of whether they are for industrial use or household use. The adsorption target of the activated carbon mainly depends on the pore diameter and volume of the activated carbon surface, the pore distribution, and the like. Therefore, a carbon source as a raw material and conditions for firing and activation are appropriately selected according to the purpose.

  However, since activated carbon is generally not suitable for adsorption of ions, it is common to use activated carbon in combination with other adsorbents. Specifically, a combination of an organic adsorbent such as activated carbon and an ion exchange resin, or an inorganic adsorbent such as activated carbon and zeolite has been proposed. Since the inorganic adsorbent has an ion exchange action, it is effective in removing heavy metal ions from water. In particular, the removal of heavy metals is an urgent issue in securing safe drinking water due to an increase in water demand accompanying a population increase and environmental deterioration.

  Then, the water purifier provided with inorganic adsorbents, such as a titanium silicate, in fibrous activated carbon is proposed (refer cited reference 1). A composite adsorbent in which titanium silicate and thermoplastic resin powder are mixed and heated to be crushed to an appropriate size and combined with granular activated carbon has been proposed (see Reference 2). In addition, a filter medium in which titanium silicate, activated carbon, and a thermoplastic resin are mixed and integrated by compression has been proposed (see cited document 3). Thereafter, a crystalline inorganic material of a metal titanate is generated using a flux method, and application to a filtering material has been proposed (see Patent Document 4).

  According to each cited document, the effect of removing lead ions in water is exhibited by the action of titanium silicate, sodium titanate, or the like. However, the activated carbon and the inorganic material exist only separately and have poor stability. Further, when both are bound using a resin binder, the pores of the activated carbon are blocked, which may cause a decrease in the adsorption performance of the activated carbon.

JP 2001-232361 A Japanese Patent No. 4361489 Special table 2011-521775 gazette JP 2011-200779 A

  In light of such circumstances, the inventors focused on an alkali metal titanate that is effective for adsorption of metal ions, and by directly growing it on the activated carbon surface, the binder was omitted to improve the adsorption performance. At the same time as obtaining an activated carbon composite material capable of integrating materials, a method for producing the activated carbon composite material was constructed.

The present invention has been proposed in view of the above situation, avoiding a decrease in the adsorption performance of activated carbon without using a binder, and further increasing the stability as an adsorbent by growing a crystalline inorganic material directly on the activated carbon surface. and that provides a method for manufacturing activated carbon composite material exhibits a complex adsorption capacity.

That is, the invention of claim 1 includes an impregnation step of impregnating an activated carbon having a particle size of 0.1 to 0.5 mm with an aqueous solution of sodium carbonate to obtain an impregnated activated carbon, and titanium oxide and sodium nitrate as a flux agent in the impregnated activated carbon. a mixing step of obtaining an activated carbon mixture was added, in a rotary kiln, the crystal of columnar or needle-like titanium sodium salt by reaction of the titanium oxide and the sodium carbonate and heating the activated carbon mixture by flux method on the surface of the activated carbon And a heating step for obtaining an activated carbon composite material formed with a weight ratio of the sodium titanate salt in the activated carbon composite material of 4 to 10% by weight of the unit activated carbon weight. Related to the method.

The invention of claim 2, wherein the activated carbon composite material according to the manufacturing method of the activated carbon composite material according to claim 1 is a lead ion removal agent.

Invention of Claim 3 concerns on the manufacturing method of the activated carbon composite material of Claim 1 or 2 with which the said activated carbon composite material is integrated in a filter body.

According to the method for producing an activated carbon composite material according to the invention of claim 1, an impregnation step of obtaining an impregnated activated carbon by impregnating an activated carbon having a particle size of 0.1 to 0.5 mm with an aqueous solution of sodium carbonate; and a mixing step of obtaining an activated carbon mixture was added sodium nitrate is fluxing agent, in a rotary kiln, the reaction by the columnar or needle-like of the titanium oxide and the sodium carbonate and heating the activated carbon mixture by flux method on the surface of the activated carbon A heating step of obtaining an activated carbon composite material in which a sodium titanate salt crystal is formed, and the weight ratio of the sodium titanate salt in the activated carbon composite material is 4 to 10% by weight of the unit activated carbon weight. Avoids the decrease in the adsorption performance of the activated carbon without the use of carbon, and forms a crystalline inorganic material directly on the activated carbon surface. Is allowed can be obtained activated carbon composite material exhibits a complex adsorption capability with enhanced stability as adsorbent.

Moreover, favorable adsorption efficiency can be provided while avoiding a decrease in processing capacity. In addition, the impurities are washed away and the remaining amount is reduced, which is convenient for crystal formation. Furthermore, it can be heated while constantly rotating and stirring, and is suitable for continuous production, is excellent in mass productivity, and can reduce the manufacturing cost of the finished activated carbon composite material.

According to the method for producing an activated carbon composite material according to the invention of claim 2 , since the activated carbon composite material is a lead ion remover in the invention of claim 1 , it is effective for measures against heavy metal contamination of tap water and tap water.

According to the method for producing an activated carbon composite material according to the invention of claim 3, since the activated carbon composite material is incorporated into the filter body in the invention of claim 1, the adsorption capacity of the activated carbon itself and the titanium adhering to the activated carbon surface It has the ability to adsorb heavy metal ions caused by acid alkali metal salts.

It is a schematic process drawing explaining the manufacturing method of the activated carbon composite material of this invention. It is a perspective view of the filter body of the present invention. It is a schematic process drawing which shows the manufacturing process of a filter body. 2 is a first electron micrograph of the activated carbon composite material surface of Example 1. FIG. 2 is a second electron micrograph of the surface of the activated carbon composite material of Example 1. FIG. 2 is a first electron micrograph of the surface of an activated carbon composite material of Comparative Example 1. 4 is a second electron micrograph of the surface of the activated carbon composite material of Comparative Example 1.

  The activated carbon composite material of the present invention is a composite material in which a crystal of an alkali metal titanate salt is directly grown on the surface of activated carbon as a base material, and the activated carbon and the crystal are integrated. As can be confirmed from the electron micrographs to be described later, it is formed directly as a columnar or needle-like crystal on the activated carbon surface or in the pores of the activated carbon. Therefore, the structure is essentially different from the structure in which the activated metal is subsequently attached or attached with crystals of alkali metal titanate to appear on the surface. The photo is a grown crystal of sodium titanate. As disclosed in the examples, sodium titanate crystals can be prepared from relatively inexpensive raw materials.

  In the activated carbon composite material of the present invention, the crystal of alkali metal titanate is produced by a flux method (flux method). In particular, when the activated carbon and the crystal are integrated, a resin binder or the like is not required, and the activated carbon grows on the surface of the activated carbon. Therefore, the activated carbon composite material simultaneously exhibits adsorption power for objects with different properties of adsorption performance of halogen, organic molecules, etc. derived from the porous structure of activated carbon and adsorption performance of metal ions caused by alkali metal titanate. It has the characteristics of a composite adsorbent.

  A manufacturing method from activated carbon AC to activated carbon composite material M will be described in order with reference to the schematic process diagram of FIG.

  First, activated carbon AC is prepared as a base material. This activated carbon AC carbonizes and fires pulverized woody plant materials rich in cellulose, such as sawn wood, sawdust (such as sawdust and sawdust), waste wood and thinned wood, waste bamboo, felled bamboo, and coconut shells. It is a carbide obtained through appropriate activation. In addition to plant materials, carbides of various resin products such as old tires and phenol resins can be added. The advantage of using activated carbon as the substrate is relatively inexpensive and can be procured quantitatively. Further, it has been conventionally used as an adsorbing and filtering material, and a wide range of substances can be adsorbed by the pores having high stability and developed on the activated carbon surface. This is because it can be said that the material is very convenient considering these factors.

  The size of the activated carbon is selected from among the activated carbons that can be procured in consideration of the use and usage of the activated carbon composite material. Therefore, when a relatively good size is studied as defined in the invention of claim 4, the average particle size of the activated carbon is in the range of 0.08 mm to 2.0 mm, preferably 0.1 mm to 1.7 mm, A range of 0.1 mm to 0.5 mm is preferable. The particle size is controlled by sieving or cyclone.

  When the particle diameter exceeds about 2.0 mm, the amount of the alkali metal titanate crystals tends to decrease, and the performance is pushed down. About the particle size of activated carbon, since a contact area increases, so that it becomes fine, adsorption | suction efficiency increases and it is preferable. However, assuming an application in which the column of a filtration device is used, for example, if the particle size is extremely small, the pressure loss of the liquid to be processed that passes through the device increases, resulting in a reduction in processing capacity. Therefore, 0.08 mm was set as the lower limit of the particle size.

  Next, an aqueous solution of the alkali metal salt is prepared for the purpose of uniformly attaching the alkali metal salt to the activated carbon. The alkali metal salt is a raw material for producing the alkali metal titanate, and sodium carbonate is used as defined in the invention of claim 5 and shown in the examples described later. In addition, sodium chloride, potassium carbonate, potassium chloride and the like are also included. The concentration of the alkali metal salt aqueous solution is 3 to 25% by weight depending on the type of salt. It is adjusted by the amount of crystals finally produced. An amount of an alkali metal salt aqueous solution corresponding to approximately 40 to 70% by weight with respect to the weight of the activated carbon is prepared, and the amount of the alkali metal salt aqueous solution is impregnated into the activated carbon. The amount of the alkali metal salt aqueous solution was defined because it can be mixed and kneaded without load with activated carbon.

  Impregnated activated carbon can be obtained by mixing and impregnating activated carbon and an aqueous alkali metal salt solution, and then dried appropriately. In the examples described later, drying was performed at about 70 ° C. for 1 hour. Here, by including drying, the water content of the alkali metal salt aqueous solution is evaporated, and the dissolved alkali metal salt can be supported on the activated carbon side.

  In this way, impregnated activated carbon impregnated with an alkali metal salt is obtained. The said process is an "impregnation process" (S1).

  After the impregnation step (S1), titanium oxide and a fluxing agent are added to the impregnated activated carbon, and each component is sufficiently mixed. For mixing on a mass production scale, a general kneader such as a known blender or kneader is used.

  Titanium oxide is an essential component for forming an alkali metal titanate crystal. Titanium oxide is preferably anatase type. Titanium oxide is preferably used in the form of powder from the viewpoint of workability.

  Originally, when an alkali metal titanate crystal is to be produced by the reaction between the alkali metal salt and titanium oxide, it is difficult to produce the crystal unless the conditions are extremely high and high. Of course, the activated carbon used as a base material may decompose at a high temperature. In addition, the energy input to the reaction system becomes excessive, which is not easy in practice. A fluxing agent is used to control this point well. By adding the fluxing agent to the reaction system, the temperature necessary for the original crystal formation is lowered. The convenience of using the fluxing agent is high because of the advantage that the temperature condition can be relaxed in the field of crystal formation.

  As the fluxing agent used for forming the alkali metal titanate crystal constituting the activated carbon composite material, sodium nitrate is used as defined in the invention of claim 5. Sodium nitrate is the same metal component as the above-mentioned alkali metal salt sodium carbonate and does not become an impurity, and can be washed away with water. When potassium carbonate is used, potassium nitrate is considered appropriate as a fluxing agent.

  An activated carbon mixture is obtained by mixing the raw materials with the impregnated activated carbon. The said process is a "mixing process" (S2).

  After the mixing step (S2), the activated carbon mixture is heated. The alkali metal salt adhering to the activated carbon surface by heating reacts with titanium oxide to produce crystals of alkali metal titanate, and in the case of sodium, crystals of sodium titanate. In particular, since a fluxing agent is also included, the temperature required for crystal formation can be lowered. In the examples described later, the temperature at which the flux agent is dissolved and crystals are formed is approximately 600 ° C.

  The activated carbon composite material M can be obtained through the heating. The said process is a "heating process" (S3).

  It is considered that the action of the alkali metal titanate, which is a crystalline component, adsorbs a metal component is due to ion exchange. When the abundance of alkali metal titanate is the same, it is desirable to increase the surface area of the crystal as much as possible in order to exhibit efficient adsorption performance of metal. For this reason, since the optimal crystal structure of the alkali metal titanate is columnar or needle-like, the generation of a structure containing many columnar or needle-like shapes is required. It is considered that the shape of the alkali metal titanate crystal formed on the activated carbon surface is influenced by the melting temperature during heating, heating conditions, the heating device, and the like.

  According to the inventors' trial, it was confirmed that crystals containing columnar or acicular crystals of alkali metal titanate developed on the surface of activated carbon, and heating under dynamic conditions rather than heating under static conditions. And better results were obtained. As an example of heating under dynamic conditions, as defined in the invention of claim 6, a known rotary furnace that heats the activated carbon mixture while rotating and stirring is used. The relationship between the heating conditions and the crystal structure of the alkali metal titanate developed on the activated carbon surface has not been elucidated at this time. Probably because of the effect of rotation and stirring on crystal growth.

  Among the rotary furnaces, a rotary kiln is a good example as defined in the invention of claim 7. The activated carbon mixture is charged from the supply unit, and when heated while passing through the rotary kiln part of the rotary kiln, the activated carbon mixture is completed and discharged as an activated carbon composite material from the discharge unit. In this case, in order to prevent excessive combustion of activated carbon, an inert gas such as nitrogen or carbon dioxide is supplied and maintained in a reducing atmosphere. The rotary kiln exhibits high production efficiency per unit time, is suitable for continuous production, and has excellent mass productivity. Therefore, it is desirable to reduce the manufacturing cost of the activated carbon composite material to be completed. In addition, when the activated carbon mixture is baked, there is no particular limitation other than the rotary furnace and the rotary kiln as long as a crystal containing columnar or needle-shaped alkali metal titanate can be developed on the activated carbon surface. For example, it is expected that the crystal body can be developed without problems even by firing the activated carbon mixture by applying vibration or impact.

  The activated carbon composite material that has been heated is washed with water to remove the fluxing agent and unreacted components. Then, it is dried by heating at 100 to 120 ° C. for 5 to 24 hours in order to evaporate the moisture. Thereafter, classification is performed so as to obtain a prescribed particle size using a sieve or a cyclone.

  The activated carbon composite material M obtained through a series of steps is in a form in which crystals of alkali metal titanate grown on the surface of the irregular-shaped activated carbon particles are present. That is, not all of the activated carbon surface is covered with the alkali metal titanate crystal. If the crystal completely covers the activated carbon, pores on the surface of the activated carbon are blocked, and the adsorption performance inherently possessed by the activated carbon is impaired. Moreover, if there are too few crystals of an alkali metal titanate, the adsorption performance of the metal component resulting from the crystal will not be exhibited.

  Therefore, in order to take advantage of both advantages, the weight of the alkali metal titanate adhering to the activated carbon per unit weight is defined. As is clear from the examples described later, 4 to 10% by weight is assumed to be a reasonable amount. When the amount is less than 4% by weight, the alkali metal titanate is too little and the desired metal content adsorption ability is lowered. Moreover, when it exceeds 10 weight%, there will be too much alkali metal titanate and it will affect the adsorption | suction effect | action of activated carbon. Therefore, the above range is appropriate from the balance of both. Depending on the purpose, the adhesion amount (crystal production amount) of the alkali metal titanate is adjusted depending on whether the adsorption performance on the activated carbon side or the alkali metal titanate side is emphasized.

  The main use of the activated carbon composite material M is water purification. This is a good example for the purpose of adsorbing and removing metal ions such as lead, iron, chromium, copper and zinc in addition to chlorine and iodine from tap water and industrial water. In particular, the alkali metal titanate is effective in adsorbing heavy metals such as lead, and is effective in preventing heavy metal contamination of tap water and tap water. In view of this, the activated carbon composite material M is used as a lead ion remover typified by heavy metals, as defined in the invention of claim 8 and as shown in the examples below. Specifically, it is possible to propose a water purification device such as a water filter combining a membrane filter such as a hollow fiber, the activated carbon composite material of the present invention, and another activated carbon. Since the activated carbon composite material of the present invention also has the adsorption performance of activated carbon itself, the volume of the adsorbent itself can be reduced and the apparatus can be downsized.

  Therefore, a filter body in which the activated carbon composite material of the present invention, in particular, the activated carbon composite material manufactured by the method of manufacturing the activated carbon composite material of the present invention is blended as an adsorbent can be produced. And the said filter body is loaded in the inside of a water purifier, a water quality treatment apparatus, etc. according to a scale. The main features of the filter body having the activated carbon composite material are, as disclosed in the above-mentioned examples or later examples, mainly the adsorption ability of the activated carbon itself and the alkali metal titanate adhering to the activated carbon surface, such as lead. It also has the ability to adsorb heavy metal ions.

  An example of the filter body containing the activated carbon composite material will be described with reference to FIG. The filter body 10 of the filter body 1 in FIG. 2A is a structure in which a filtration part 11 having filtration ability is aggregated on the surface of a hollow cylindrical core member 12 having appropriate permeation holes. Moreover, accessories, such as the cap 14, are attached like the filter body 1A of FIG.2 (b), and the convenience of handling is achieved. In the figure, the surface of the filtration part 11 of the filter body 10 is covered and protected by a highly permeable cloth 13 such as a nonwoven fabric. And the cap 14 which protects the upper and lower sides of the filtration part 11 is covered (the shape and material of a cap differ with uses).

  The filter part of the filter body of the filter body is formed, for example, by adding an appropriate amount of an activated carbon composite material, polyethylene fibers, an acrylic fiber binder, and further fibrous activated carbon in order to enhance their binding properties. It is a structure in which the shape retention of the filtration part is ensured by other components of the activated carbon composite material.

  A production example of a filter body containing an activated carbon composite material will be described with reference to FIG. First, the activated carbon composite material M and the fibrous constituent material 22 are put into water and mixed sufficiently to prepare the mixed slurry 20. The fibrous constituent material 22 is selected from, for example, polyethylene fiber, acrylic fiber, or fibrous activated carbon.

  Inside the hollow cylindrical core member 12 is inserted a porous die rod member 26 for sucking the mixed slurry-like material under reduced pressure. The hollow cylindrical core member 12 is formed with pores (not shown) for permeation, and the die rod member 26 is made of porous stainless steel. After the integrated product of the hollow cylindrical core member 12 and the mold bar-like member 26 is lowered into the mixed slurry-like article 20, the mixed slurry-like article 20 is hollow-cylindrical by being sucked under reduced pressure through the mold rod-like member 26. The core member 12 is attracted and attached to the side surface. As shown in the notch portion shown in the drawing, a slurry adherend 27 is formed on the surface of the hollow cylindrical core member. After a predetermined amount of the slurry adherend 27 is formed, the slurry is pulled up from the mixed slurry, and the mold bar 26 is removed. In this way, the adhering adherend 25 having the slurry adhering portion 27 on the surface of the hollow cylindrical core member 12 is obtained. Thereafter, the adsorbed adherend 25 is heated and dried in the dryer 30.

  The adsorption function itself of the purification filter body is borne by the activated carbon composite material. When an acrylic fiber, a carbon fiber, or the like is mixed here, the activated carbon composite material acts as a structural material for holding each other. It acts as a binding material that holds the activated carbon composite material together, and acts as a net-like structural material for maintaining the shape of the filter body.

  Of course, the structure and manufacturing method of the filter body are not limited to the examples shown and described in detail, and appropriate structures and manufacturing methods can be adopted. For example, a filter body having a simple structure such as filling an activated carbon composite material itself into a storage container provided with a plurality of small holes may be used. In addition, the filter body of the disclosed example can be combined with other existing filter bodies for filtration to increase the water treatment capacity comprehensively. That is, it is appropriately constructed in consideration of the filtration device to which the filter body is applied, the water purification scale, and the like.

  The inventors created activated carbon composite materials of Examples 1 to 4 and Comparative Examples 1, 2, and 5 using activated carbon, alkali metal salt, and flux agent. Comparative examples 3 and 4 were prepared as examples in which the crystal was fixed with a binder. In addition, various adsorption performances were also measured. Details are shown in Tables 1 and 2.

[Raw materials]
Coconut shell activated carbon manufactured by Futamura Chemical Co., Ltd .: CW5100A (particle size 0.15-0.3 mm), Coconut shell activated carbon manufactured by the company: CW480A (particle size 0.18-0.36 mm), Coconut shell activated carbon manufactured by the company: CW360A (particle size 0.25-0.5 mm), company-made coconut shell activated carbon: CW130A (particle size 0.5-1.7 mm), company-made coconut shell activated carbon: CW8200A (particle size 0.08-0. 18 mm) was used. The particle size was controlled by changing the type of sieve.

  Sodium carbonate (Daito Chemical Co., Ltd.) was used as the alkali metal salt, and sodium nitrate (Daito Chemical Co., Ltd.) was used as the flux agent. Titanium dioxide (Daito Chemical Co., Ltd.) was used. In addition, as a control, sodium titanate (Futamura Chemical Co., Ltd.) was used, and the binder was fluororesin (polytetrafluoroethylene) (Asahi Glass Co., Ltd.) and polyethylene (Miki Sangyo Co., Ltd., trade name: Flocene) It was used.

[Creation of activated carbon composite material]
<Example 1>
First, 200 g of activated carbon (particle size: 0.15 to 0.3 mm) was weighed in accordance with the raw material species and the amount thereof shown in Table 1 below. Ion exchange water was weighed in 120 mL, which is 60% of the weight of activated carbon, and 9.6 g of alkali metal salt sodium carbonate was added and dissolved therein. The aqueous solution was impregnated with activated carbon and stirred appropriately, and then dried at 70 ° C. for 1 hour to obtain impregnated activated carbon. To this impregnated activated carbon, 43.5 g of titanium dioxide and 30.8 g of sodium nitrate as a flux agent were added and mixed uniformly to obtain an activated carbon mixture. The activated carbon mixture was put into a rotary kiln and heated. As a heating condition, the temperature rising rate was 300 ° C./hr, and 600 ° C. at which the flux agent melted and crystals of sodium titanate grew was maintained for 1 hour. And it cooled to 500 degreeC with the temperature-fall rate of 20 degreeC / hr. During the heating, nitrogen gas was passed to create a reducing atmosphere.

<Example 2>
In Example 2, the activated carbon of Example 1 was changed to activated carbon having a particle size of 0.18 to 0.36 mm. 200 g of the activated carbon was weighed. To 120 mL of ion exchange water, 4.1 g of sodium carbonate was added and dissolved. The aqueous solution was impregnated with activated carbon and stirred appropriately, and then dried at 70 ° C. for 1 hour to obtain impregnated activated carbon. To this impregnated activated carbon, 18.6 g of titanium dioxide and 13.2 g of sodium nitrate were added and mixed uniformly to obtain an activated carbon mixture. The heating conditions and apparatus for the activated carbon mixture were the same as in Example 1.

<Example 3>
In Example 3, the activated carbon of Example 1 was changed to activated carbon having a particle size of 0.15 to 0.3 mm. 200 g of the activated carbon was weighed. To 120 mL of ion exchange water, 4.1 g of sodium carbonate was added and dissolved. The aqueous solution was impregnated with activated carbon and stirred appropriately, and then dried at 70 ° C. for 1 hour to obtain impregnated activated carbon. To this impregnated activated carbon, 18.6 g of titanium dioxide and 13.2 g of sodium nitrate were added and mixed uniformly to obtain an activated carbon mixture. The heating conditions and apparatus for the activated carbon mixture were the same as in Example 1.

<Example 4>
In Example 4, the activated carbon of Example 1 was changed to activated carbon having a particle size of 0.25 to 0.5 mm. 200 g of the activated carbon was weighed. 23.8 g of sodium carbonate was added to 120 mL of ion exchange water and dissolved. The aqueous solution was impregnated with activated carbon and stirred appropriately, and then dried at 70 ° C. for 1 hour to obtain impregnated activated carbon. To this impregnated activated carbon, 107.1 g of titanium dioxide and 76.1 g of sodium nitrate were added and mixed uniformly to obtain an activated carbon mixture. The heating conditions and apparatus for the activated carbon mixture were the same as in Example 1.

<Comparative example 1>
In Comparative Example 1, 200 g of the same activated carbon as in Example 1 was used. 9.6 g of sodium carbonate was added to 120 mL of ion exchange water and dissolved. The aqueous solution was impregnated with activated carbon and stirred appropriately, and then dried at 70 ° C. for 1 hour to obtain impregnated activated carbon. To this impregnated activated carbon, 43.5 g of titanium dioxide and 30.8 g of sodium nitrate were added and mixed uniformly to obtain an activated carbon mixture. The activated carbon mixture was transferred to a crucible and heated in a stationary furnace. As a heating condition, the temperature rising rate was 300 ° C./hr, and 600 ° C. at which the flux agent melted and crystals of sodium titanate grew was maintained for 1 hour. And it cooled to 500 degreeC with the temperature-fall rate of 20 degreeC / hr. During the heating, nitrogen gas was passed to create a reducing atmosphere.

<Comparative example 2>
In Comparative Example 2, the same activated carbon 100 g as in Example 1 was used. 23.8 g of sodium carbonate was added to 120 mL of ion exchange water and dissolved. The aqueous solution was impregnated with activated carbon and stirred appropriately, and then dried at 70 ° C. for 1 hour to obtain impregnated activated carbon. To this impregnated activated carbon, 107.1 g of titanium dioxide and 76.1 g of sodium nitrate were added and mixed uniformly to obtain an activated carbon mixture. The heating conditions and apparatus for the activated carbon mixture were the same as in Example 1.

<Comparative Example 3>
Comparative Example 3 is an example in which sodium titanate is bonded (attached) to activated carbon through a fluororesin binder. 200 g of the same activated carbon as in Example 1, 10 g of sodium titanate, and 6 g of a fluororesin binder were mixed and heated at 120 ° C. for 8 hours.

<Comparative example 4>
Comparative Example 4 is an example in which sodium titanate is bonded (attached) to activated carbon via a polyethylene resin binder. 200 g of the same activated carbon as in Example 1 and 10 g of sodium titanate were mixed, 4 g of polyethylene resin binder was dispersed in 120 mL of ion-exchanged water, and this binder solution was sprayed onto a mixture of activated carbon and sodium titanate. Then, it heated at 120 degreeC for 8 hours.

<Comparative Example 5>
In Comparative Example 5, the activated carbon of Example 1 was changed to activated carbon having a particle size of 0.5 to 1.7 mm. 200 g of the activated carbon was weighed. 9.6 g of sodium carbonate was added to 120 mL of ion exchange water and dissolved. The aqueous solution was impregnated with activated carbon and stirred appropriately, and then dried at 70 ° C. for 1 hour to obtain impregnated activated carbon. To this impregnated activated carbon, 43.5 g of titanium dioxide and 30.8 g of sodium nitrate were added and mixed uniformly to obtain an activated carbon mixture. The heating conditions and apparatus for the activated carbon mixture were the same as in Example 1.

[Measurement of physical properties, etc.]
<Filling density>
About the packing density of the activated carbon composite material of an Example and a comparative example, it is based on "6.7 packing density" of the activated carbon test method of JISK1474 (2007), and "6.7.1 manual filling method". (G / mL) was measured.

<Iodine adsorption performance>
In accordance with the test method “6.1.1.1 Iodine adsorption performance” of the activated carbon test method of JIS K 1474 (2007), the iodine adsorption performance (mg / g) of the activated carbon composite materials of Examples and Comparative Examples was determined. It was measured.

<Crystal weight of sodium titanate>
About the weight (relative weight ratio) of the crystal | crystallization of the sodium titanate salt produced | generated on the surface of activated carbon, it measured and calculated by the method based on JISK1474 (2007) "6.9 ignition residue." Each sample of the activated carbon composite material of the example and the comparative example and the ignition residue of the activated carbon used in the preparation of the activated carbon composite material of the example and the comparative example were determined (unit%). And the difference between ignition residues was calculated | required and the relative weight ratio of the sodium titanate salt crystal to the activated carbon weight of the sample of the said Example etc. was computed.

<Crystal shape observation>
The crystal shape of the sodium titanate salt formed on the surface of the activated carbon composite material was photographed with a scanning electron microscope (SEM) and specifically identified. As a result, needle-like or a mixture of needle-like and columnar shapes and crystal growth of only columnar shapes were obtained. Many of the crystals of sodium titanate were formed in the pores developed on the surface of the activated carbon.

  4 to 7 show representative electron micrographs. FIG. 4 is a 20000 times magnified photograph of the surface of the activated carbon composite material of Example 1, and crystals were formed in the pores of the activated carbon. The crystal is a hybrid of columnar and needle-like shapes. FIG. 5 is an enlarged photograph of 20,000 times inside another pore, which is almost a needle crystal (the needle shape includes a columnar shape). On the other hand, FIG. 6 is a 10,000 times magnified photograph of the surface of the activated carbon composite material of Comparative Example 1, and plate crystals were generated in the pores of the activated carbon. FIG. 7 is an enlarged photo of 20,000 times in the same pore, and most of the plate crystals.

<Dissolvable lead removal performance>
About each activated carbon composite material of an Example and a comparative example, it measured based on "6.4.6 soluble lead removal performance test" of the household water purifier test method of JIS S3201 (2010). In the measurement, 100 cc of the activated carbon composite material was packed in a column having an inner diameter of 40 mm. Raw water containing 50 ppb soluble lead was prepared and passed through a packed column at a flow rate of 2.0 L / min (SV: 1200 hr ⁻¹ ). Measure the removal rate of soluble lead (lead ions) by the activated carbon composite material in the column, and calculate the value obtained by dividing the total water flow rate when the removal rate reaches 80% by the packing amount (cc) of the activated carbon composite material. It was set as the performance value (L / cc) of the activated carbon composite material.

<Free residual chlorine removal performance>
About each activated carbon composite material of an Example and a comparative example, it measured based on "6.5.1 free residual chlorine filtration ability test" of the household water purifier test method of JIS S3201 (2010). In the measurement, 100 cc of the activated carbon composite material was packed in a column having an inner diameter of 40 mm. Raw water containing 2.0 ppm free residual chlorine was prepared and passed through a packed column at a flow rate of 2.0 L / min (SV: 1200 hr ⁻¹ ). The removal rate of free residual chlorine by the activated carbon composite material in the column was measured, and the value obtained by dividing the total water flow rate when the removal rate reached 80% by the packed amount (cc) of the activated carbon composite material The performance value (L / cc) was used.

<Crystal supportability evaluation>
The crystal supportability was judged from the relative weight ratio of sodium titanate crystals to the weight of the activated carbon of the sample. A crystal amount of sodium titanate salt of 4% by weight (wt%) or more was evaluated as “◯”, and a crystal amount of 4% by weight (wt%) or less was evaluated as “x”.

<Comprehensive evaluation>
About the activated carbon composite material, various adsorbing performance was considered comprehensively and the quality as a whole was evaluated.
An example satisfying all of iodine adsorption performance of 1000 mg / g or more, soluble lead removal performance of 7 L / cc or more, and free residual chlorine removal performance of 14 L / cc or more was evaluated as “excellent”.
An example that satisfies all of iodine adsorption performance of 800 mg / g or more, soluble lead removal performance of 5 L / cc or more, and free residual chlorine removal performance of 10 L / cc or more was evaluated as “good”.
The evaluation of “impossible” was an example in which even one item was missing among iodine adsorption performance of 800 mg / g or more, soluble lead removal performance of 5 L / cc or more, and free residual chlorine removal performance of 10 L / cc or more.

  Tables 1 and 2 show the amount of activated carbon used (g), the particle size range (mm), the amount of each raw material (g), the way of supporting the crystals, the heating device, and the heating conditions. / ML), crystal weight (% by weight) of sodium titanate, crystal shape, iodine adsorption performance (mg / g), soluble lead removal performance (L / cc), free residual chlorine removal performance (L / cc), The crystal supportability and overall evaluation are shown in order.

[Results and discussion of activated carbon composite materials]
From the comprehensive evaluation regarding the removal performance of the examples and comparative examples, all of the examples are good or better, and in particular, Examples 1 to 3 are excellent evaluations. The particle diameter of the activated carbon used in the order of Examples 1, 2, and 3 becomes finer. In accordance with this, the soluble lead removal performance and free residual chlorine removal performance caused by sodium titanate increased. The cause is considered to be the increase in the contact area of the entire activated carbon per unit weight. Comparative Example 5 is an example of using activated carbon having a particle size larger than that of the example. Even if the amount of reagent necessary for crystal formation is the same as in Example 1, the contact area per unit weight is reduced, so that it can be said that the various adsorption performances have decreased.

  Example 4 and Comparative Example 2 are examples in which the amount of crystal of sodium titanate formed on the activated carbon surface is larger than in other examples. If the weight ratio of the sodium titanate salt crystals is about Example 4, the balance of iodine adsorption performance, soluble lead removal performance, and free residual chlorine removal performance is good, and the soluble lead removal performance improves with the amount of crystals. . Based on this, the weight ratio of the sodium titanate salt crystal can be adjusted by paying attention to the removal object to be emphasized. However, in the case of Comparative Example 2, since the sodium titanate crystal was excessive at 19.8% by weight, the original pores of the activated carbon were clogged and the various adsorption performances were adversely affected. Therefore, an appropriate weight ratio of sodium titanate crystal converges to 4 to 10% by weight of the unit activated carbon weight.

  Comparative Examples 3 and 4 are examples in which a resinous binder was used when depositing sodium titanate on activated carbon. For this reason, the pores of the activated carbon are obstructed, and the iodine adsorption performance and free residual chlorine removal performance derived from the activated carbon are significantly reduced. Therefore, the advantage that crystals can be directly generated on the activated carbon surface as in the present invention is very large as compared with the case of deposition using a known resin binder.

  It was also clarified that when the raw material of the sodium titanate salt crystal and the fluxing agent are mixed and heated together with the activated carbon, the shape of the crystal produced differs depending on the heating conditions of the heating device. All of the formation of the needle-like crystals is heating that is continuously moved using a rotary kiln. In contrast, the heating of the stationary furnace of Comparative Example 1 produced only plate crystals (see the electron micrographs of FIGS. 2 to 5). As is clear from the imaging results, examples of heating under dynamic conditions using a rotary kiln were all acicular crystals or mixed crystals of acicular and columnar shapes. However, in the case of heating under the static conditions of Comparative Example 1, acicular crystals could not be found, and only plate crystals were grown.

  When the difference in crystal shape between Example 1 and Comparative Example 1, that is, the presence or absence of acicular crystals and the level of soluble lead removal performance were compared, a clear difference appeared. From this, the soluble lead removal performance increases as the sodium titanate has an acicular (columnar) crystal structure. In addition, for this purpose, a production method that continues to move during heating with a rotary kiln or the like is advantageous. The reason why the soluble lead removal performance increases as the acicular (columnar) crystal structure increases is that the surface area of the crystal increases and the contact area between sodium titanate and soluble lead increases.

  The reason why the conditions at the time of heating and the shape of the generated crystal are different is not clear at present. If the conditions are static during heating, the crystals themselves are likely to spread in a plate shape. However, activated carbon is a dynamic heating condition that rolls while rotating in the rotary kiln, and crystals are expected to grow in the shape of columns or needles due to the effects of rotation and stirring. Presumably, the growth of needle-like crystals approximates the corner growth model in confetti.

[Creation of activated carbon composite material for filter body]
The inventors who confirmed the superiority of the activated carbon composite material of the present invention and the manufacturing method thereof from the comparison between Examples 1 to 4 and Comparative Examples 1 to 5 continued to create a filter body incorporating the activated carbon composite material. . And iodine adsorption | suction performance, soluble lead removal performance, and free residual chlorine removal performance were measured, and the performance as a filter body was evaluated collectively. Prior to preparation of the filter body, activated carbon composite materials of Example 5 and Comparative Examples 6 to 8 were prepared. Here, activated carbon having a particle size smaller than that of the above-mentioned examples was selected based on a comparison between Examples 2 and 3.

<Example 5>
In Example 5, the activated carbon of Example 1 was changed to a particle size of 0.08 to 0.18 mm, and 200 g of the activated carbon was weighed. Subsequent raw material blending amounts, heating conditions for the activated carbon mixture, and the apparatus were the same as in Example 1, and the activated carbon composite material of Example 5 was prepared.

<Comparative Example 6>
In Comparative Example 6, activated carbon having a particle size of 0.08 to 0.18 mm was used. The activated carbon composite material of the comparative example 6 was created as the raw material compounding quantity similar to the said comparative example 1, and the heating conditions of an activated carbon mixture.

<Comparative Example 7>
In Comparative Example 7, the activated carbon used in Comparative Example 3 was changed to a particle size of 0.08 to 0.18 mm. Thereafter, an activated carbon composite material (an example of using a fluororesin binder) of Comparative Example 7 was prepared as the same raw material blending amount as in Comparative Example 3 and heating conditions of the activated carbon mixture.

<Comparative Example 8>
In Comparative Example 8, the activated carbon used in Comparative Example 4 was changed to a particle size of 0.08 to 0.18 mm. Thereafter, the activated carbon composite material (use example of polyethylene resin binder) of Comparative Example 7 was prepared as the raw material blending amount similar to Comparative Example 4 and the heating conditions of the activated carbon mixture.

[Creation of filter body for each activated carbon composite material]
The filter body was prepared in accordance with the preparation method of sucking from the mixed slurry disclosed in FIG. Therefore, 85 parts by weight of each of the activated carbon composite materials of Example 5 and Comparative Examples 6, 7, and 8 and 10 parts by weight of fibrous activated carbon (Futamura Chemical Co., Ltd., trade name: phenol-based fibrous activated carbon), acrylic 5 parts by weight of resin fibers (manufactured by Toyobo Co., Ltd., trade name: Bipal) were weighed. These three types were put into water and then mixed uniformly to prepare a mixed slurry.

  Next, a hollow cylindrical core member made of polypropylene having an outer diameter of 24 mm, an inner diameter of 20 mm, a total length of 50 mm, and pores having a diameter of 2 mm was prepared. A porous stainless steel metal rod member was inserted into the hollow cylindrical core member and fixed, and the mixed slurry was put into the liquid. The solid content was drawn from the mixed slurry by suction under reduced pressure, and was applied to the surface of the hollow cylindrical core member by about 13 mm to form a slurry applied portion. The die rod-shaped member was removed from the hollow cylindrical core member to obtain an adsorbed adherend that was an integrated product of the slurry adherend and the hollow cylindrical core member.

  The adsorbed adherend was placed in a dryer and heated and dried at 100 ° C. for 12 hours. Thus, filter bodies incorporating the activated carbon composite materials of Example 5 and Comparative Examples 6, 7, and 8 were sequentially prepared. The dimensions of all the filter bodies were an outer diameter of 50 mm, an inner diameter of 20 mm, and an overall height of 50 mm. In addition, also in distinction of a filter body, the name of Example 5 and Comparative Examples 6, 7, and 8 is used according to the activated carbon composite material from which it originates.

[Measurement of various adsorption performances of filter bodies]
The iodine adsorption performance conforms to the test method of “6.1.1.1 iodine adsorption performance” of the activated carbon test method of JIS K 1474 (2007), and the iodine adsorption performance (mg of filter bodies of Examples and Comparative Examples). / G) was measured.

The soluble lead removal performance was measured in accordance with “6.4.6 soluble lead removal performance test” in the household water purifier test method of JIS S 3201 (2010). In the measurement, raw water containing 50 ppb of soluble lead was prepared, and water was passed through the housing loaded with the filter bodies of Examples and Comparative Examples at a flow rate of 1.5 L / min (SV: 1200 hr ⁻¹ ). Measure the removal rate of soluble lead (lead ion) by the activated carbon composite material of the filter body, and calculate the value obtained by dividing the total water flow when the removal rate reaches 80% by the filling amount (cc) of the activated carbon composite material. It was set as the performance value (L / cc) of the activated carbon composite material.

The free residual chlorine removal performance was measured according to “6.5.1 Free residual chlorine filtration ability test” of the domestic water purifier test method of JIS S 3201 (2010). At the time of the measurement, raw water containing 2.0 ppm of free residual chlorine was prepared, and water was passed through the housing loaded with the filter bodies of Examples and Comparative Examples at a flow rate of 1.5 L / min (SV: 1200 hr ⁻¹ ). . The removal rate of free residual chlorine by the activated carbon composite material of the filter body is measured, and the value obtained by dividing the total water flow rate when the removal rate reaches 80% by the filling amount (cc) of the activated carbon composite material The performance value (L / cc) was used.

[Evaluation of filter body]
The crystal supportability of the filter body was judged by the amount of sodium titanate crystal spilled from the activated carbon composite material when the filter body was molded. Examples with few spilled crystals were evaluated as “◯”, and examples with many spilled crystals were evaluated as “x”.

A comprehensive evaluation was made by comprehensively considering various adsorption performances as a filter body.
An example satisfying all of iodine adsorption performance of 1000 mg / g or more, soluble lead removal performance of 15 L / cc or more, and free residual chlorine removal performance of 60 L / cc or more was evaluated as “excellent”.
An example satisfying all of iodine adsorption performance of 800 mg / g or more, soluble lead removal performance of 10 L / cc or more, and free residual chlorine removal performance of 50 L / cc or more was evaluated as “good”.
An example in which there was one missing item among iodine adsorption performance of 800 mg / g or more, soluble lead removal performance of 7 L / cc or more, and free residual chlorine removal performance of 40 L / cc or more was evaluated as “impossible”.

  For each filter body of Example 5 and Comparative Examples 6, 7, and 8, Table 3 shows the raw material blending ratio (parts by weight), iodine adsorption performance (mg / g), soluble lead removal performance (L / cc), In addition, physical properties of free residual chlorine removal performance (L / cc), crystal supportability, and comprehensive evaluation are shown in this order.

[Results and consideration of filter body]
From the evaluation results of Example 5, even when the activated carbon composite material was incorporated into the filter body, various good adsorption performances including soluble lead were shown in the same manner as when the activated carbon composite material was measured alone. This proved that the activated carbon composite material is suitable for actual demand as a filter. The difference in performance between Example 5 and Comparative Example 6 is the difference in the manufacturing method of the activated carbon composite material. As described in Comparative Example 1 above, it can be considered that the crystal shape of sodium titanate is different.

  For the examples prepared using the resinous binders of Comparative Examples 7 and 8, as mentioned in Comparative Examples 3 and 4 above, the pores of activated carbon were blocked and the sodium titanate crystals themselves were coated. The performance degradation is obvious. For this reason, the effect of the activated carbon composite material which can produce | generate a crystal | crystallization directly on the activated carbon surface like this invention is large even when processed into a filter body, and its utility value is very high.

Activated carbon composite material manufactured by the manufacturing method of the activated carbon composite material of the present invention, since it is formed by growing a crystal of a direct titanate sodium salt on activated carbon, while taking advantage of the adsorption performance of activated carbon per se, sodium titanate It also has ion exchange adsorption performance. Further, the production itself is simple. Therefore, it is possible to replace an existing adsorbing material used for removing metal components. In addition, even if the activated carbon composite material is processed into a filter body, sufficient adsorption performance can be exhibited, so that it can be used for an existing filtration device.

AC activated carbon M activated carbon composite material (composite adsorbent)
DESCRIPTION OF SYMBOLS 1 Filter body 10 Filter main body 11 Filtration part 12 Hollow cylindrical core member 20 Mixed slurry-like material 22 Fibrous constituent material 25 Adsorption adherend 26 Mold stick-shaped member 27 Slurry adherence part 30 Dryer

Claims (3)

An impregnation step of impregnating activated carbon having a particle size of 0.1 to 0.5 mm with an aqueous solution of sodium carbonate to obtain impregnated activated carbon;
A mixing step of adding titanium oxide and sodium nitrate as a fluxing agent to the impregnated activated carbon to obtain an activated carbon mixture;
In rotary kiln, the heating step of obtaining an activated carbon composite material formed crystals of columnar or needle-like titanium sodium salt by reaction of the titanium oxide and the sodium carbonate and heating the activated carbon mixture by flux method on the surface of the activated carbon Have
The weight ratio of the said sodium titanate salt in the said activated carbon composite material is 4 to 10 weight% of unit activated carbon weight. The manufacturing method of the activated carbon composite material characterized by the above-mentioned.   The method for producing an activated carbon composite material according to claim 1, wherein the activated carbon composite material is a lead ion remover.   The method for producing an activated carbon composite material according to claim 1 or 2, wherein the activated carbon composite material is incorporated into a filter body.

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