JP2007014826A - Porous molding and its producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous molding exhibiting excellent cost performance when used for adsorbing/removing low-concentration phosphorus, boron, fluorine or arsenic contained in industrial water or waste water and to provide a method for producing the porous molding. <P>SOLUTION: The porous molding contains an organic polymer resin and an inorganic ion adsorbent and has fibrils each of which has voids therein. At least a part of the void is opened to the surface of the fibril. The inorganic ion adsorbent containing at least one of the metal oxides shown by formula (I): MN<SB>x</SB>O<SB>n</SB>-mH<SB>2</SB>O (wherein x is 0-3; n is 1-4; m is 0-6; M and N are each a metallic element selected from the group consisting of Ti, Zr, Sn, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Si, Cr, Co, Ga, Fe, Mn, Ni, V, Ge, Nb and Ta and are different from each other) is deposited on the outside surface of the fibril and on the surface of the internal void. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a porous molded body and a method for producing the same. In particular, the present invention relates to a porous molded body suitable for an adsorbent that selectively adsorbs and removes phosphorus, boron, arsenic, fluorine ions, etc. contained in river water, sewage treated water, and factory effluent, and a method for producing the same. It is.

In recent years, environmental standards such as drinking water, industrial water, industrial wastewater, sewage treated water, environmental water such as phosphorus, boron, arsenic, and fluoride ions have been strengthened due to problems of environmental pollution and eutrophication. It has been demanded.
Phosphorus is one of the causative substances of eutrophication, and regulations are getting stronger in closed waters. In addition, it is an element that is depleted, and there is a need for technology to recover it from wastewater and reuse it.
Boron is an essential element for plant growth. However, boron is known to have an adverse effect on plant growth when present in excess. Furthermore, it has been pointed out that when it is contained in drinking water, it may cause health problems such as a decrease in reproductive function when it is contained in drinking water.

Arsenic is contained in wastewater from non-ferrous metal refining industry, heat from geothermal power plants, and groundwater in specific areas. The toxicity of arsenic has been known for a long time, but it is accumulative in the living body and is said to cause chronic poisoning, weight loss, sensory injury, liver damage, skin deposition, skin cancer and the like.
Fluorine is often contained in waste water from metal refining, glass, electronic material industries, and the like. There is concern about the effects of fluorine on the human body, and it is known that excessive intake causes chronic fluorine poisoning such as patchy teeth, osteosclerosis, and thyroid disorders.
Furthermore, with the development of civilization, there is a concern that the amount of these harmful substances released will increase, and there is a need for a technique for efficiently removing these harmful substances.

  Conventional technologies for removing these harmful substances include attaching titanium, zirconium, or tin hydrated ferrite to a three-dimensional network structure made of polyurethane or polyacrylic acid resin using an appropriate binder. Is known (see Patent Document 1). This known adsorbent is obtained by adhering hydrous ferrite to a three-dimensional network structure using a binder, and the fine pores present on the surface of hydrous ferrite that is an adsorbent substrate. Therefore, there is a drawback that the ion exchange ability inherent to the adsorption substrate is not sufficiently exhibited and the adsorption rate is slow. Moreover, since it has a large space | gap, the load of the adsorption substrate in a unit volume is low. That is, there is a problem that the adsorption performance is not sufficient. Also, the manufacturing method is complicated.

  Further, an adsorbent in which a hydrous cerium powder is supported on a polymer material is known (see Non-Patent Document 1). Although this adsorbent is porous, there is a thin film called a skin layer on the surface, so the diffusion rate of adsorbents such as phosphorus and boron into the adsorbent becomes slow, and the adsorption performance is still sufficient. Has the disadvantage of not.

  Patent Document 2 discloses an adsorbent in which an adsorption substrate made of hydrous zirconium oxide is supported by an impregnation method on a porous molded body made of cellulose. Since this adsorbent is supported by an impregnation method later, the adsorbent has a weak binding force and has a drawback that the adsorbing substrate flows out during repeated use. In addition, cellulose easily swells in water, and when packed in a column and passed through, the molded body is compressed and pressure loss increases. In addition, since cellulose is degradable by living organisms, there is a problem that it is difficult to adapt to water treatment in which various microorganisms such as sewage are mixed in terms of durability in repeated use.

Against this background, there is a great demand for higher adsorption performance and higher durability performance for adsorbents that can be used for removing ions such as phosphorus, boron, arsenic and fluorine harmful to health and the environment from water.
On the other hand, the price is required to be lower.
JP-A-9-187646 JP 2002-38038 A Industry and environment, September 1999, p81-85

  The present invention has high adsorption performance and high durability performance, and the production cost is suppressed, and it is extremely cost effective for adsorption removal of low concentrations of phosphorus, boron, fluorine, arsenic, etc. contained in water and wastewater. It aims at providing the porous molded object which can be utilized as an outstanding adsorbent, and its manufacturing method.

  As a result of intensive studies to solve the above problems, the present inventors have dissolved an organic polymer resin in an appropriate good solvent, and are further soluble in the good solvent and have an affinity for the organic polymer resin. By suspending the inorganic ion adsorbent powder, which is an adsorption substrate, in a polymer solution in which a water-soluble polymer with a solution is mixed, and forming a poor solvent as a coagulation bath, there is no skin layer on the surface. It was found that a porous molded body having excellent surface opening properties was obtained, and that this porous molded body has high adsorption performance and durability performance. Furthermore, the present inventors can manufacture an inorganic ion adsorbent having a specific composition and structure without substantially reducing the adsorption performance such as adsorption speed and adsorption capacity and durability against repeated use. It has been found that the cost can be greatly reduced, and the present invention has been completed based on these findings.

That is, the present invention is as follows.
1. A porous molded article having an open surface on the outer surface, comprising an organic polymer resin and an inorganic ion adsorbent, wherein the inorganic ion adsorbent is a metal oxide represented by the following formula (I) And at least a part of the voids are open at the surface of the fibril, and the outer surface of the fibril and the voids inside the fibril. A porous molded article having an inorganic ion adsorbent supported on a surface thereof.
_{MN x O n · mH 2 O} (I)
(Wherein x is 0 to 3, n is 1 to 4, m is 0 to 6, and M and N are Ti, Zr, Sn, Sc, Y, La, Ce, Pr, Nd, Sm, Eu. Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Si, Cr, Co, Ga, Fe, Mn, Ni, V, Ge, Nb and Ta are metal elements selected from the group Are different from each other.)

2. 1. The metal oxide represented by the formula (I) is one or more selected from the group of any of the following (a) to (c). The porous molded body described.
(A) hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated lanthanum oxide, and hydrated yttrium oxide (b) consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium A composite metal oxide of a metal element selected from the group and a metal element selected from the group consisting of aluminum, silicon, and iron (c) activated alumina

3. 1. The inorganic ion adsorbent contains a plurality of types of metal oxides represented by the formula (I). Or 2. The porous molded body described.
4). The inorganic ion adsorbent has a structure in which the metal oxide (A) represented by the formula (I) is covered with another metal oxide (B) represented by the formula (I). 3. The porous molded body described.
5. The metal oxide (A) is an oxide in which at least one of M and N in the formula (I) is a metal element selected from the group consisting of aluminum, silicon, and iron, and the metal oxide (B) Is a metal element oxide or activated alumina selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium, at least one of M and N in formula (I). The porous molded body described.

6). 1. The communication hole has a maximum pore diameter layer near the surface of the molded body. ~ 5. The porous molded object as described in any one of these.
7). 1. The average particle size is 100-2500 μm and is substantially spherical ~ 6. The porous molded object as described in any one of these.
8). The porous molded body contains at least one selected from the group consisting of ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile (PAN), polysulfone (PS), and polyvinylidene fluoride (PVDF) as an organic polymer resin. 1 ~ 7. The porous molded object as described in any one of these.

9. In a method for producing a porous molded article comprising an organic polymer resin and an inorganic ion adsorbent,
As the inorganic ion adsorbent, an inorganic ion adsorbent containing at least one metal oxide represented by the formula (I) is used,
A method of forming a porous molded body, comprising mixing an organic polymer resin, a good solvent for the organic polymer resin, the inorganic ion adsorbent, and a water-soluble polymer, and then molding and coagulating in a poor solvent.
10. An inorganic ion adsorbent comprising a structure in which the metal oxide (B) covers the metal oxide (A).

11. The metal oxide (A) is an oxide in which at least one of M and N in the formula (I) is a metal element selected from the group consisting of aluminum, silicon, and iron, and the metal oxide (B) Is a metal element oxide or activated alumina selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum and yttrium. The inorganic ion adsorbent described.

Since the porous molded body of the present invention has a high openability on the outer surface, the diffusion of the substance to be adsorbed into the molded body is fast and the processing speed is fast.
In addition, since the fibrils carrying the inorganic ion adsorbents are also porous, even the inorganic ion adsorbents embedded in the fibrils can function effectively as adsorbents, and the contact efficiency with the adsorption target substance is extremely high. .
Further, since the water-soluble polymer does not block the active site by coating between the adsorption substrate and the supported fibril, the adsorption activity of the inorganic ion adsorbent is high.
On the other hand, since the porous molded body of the present invention is molded after kneading the adsorption substrate and the binder polymer, the inorganic adsorbent that is the adsorption substrate is firmly supported on the binder polymer and does not flow out during repeated use, and is durable. High nature.

Moreover, since the organic polymer resin carrying the inorganic ion adsorbent of the present invention hardly swells in water, it is excellent in pressure resistance and durability in water treatment applications. Furthermore, since it is not degradable by living organisms, it is excellent in terms of durability of repeated use even in water treatment applications where miscellaneous microorganisms such as sewage are mixed.
Furthermore, since an inexpensive raw material is used for the production of the contained inorganic ion adsorbent, the production cost is kept low and the economy is excellent.
That is, according to the present invention, there is provided a porous molded body that can be used as an adsorbent that is extremely excellent in cost performance when adsorbing and removing low concentrations of phosphorus, boron, fluorine, arsenic and other ions contained in water and wastewater. can get.

Hereinafter, the present invention will be specifically described focusing on its preferred form.
First, the structure of the porous molded body of the present invention will be described.
The porous molded body of the present invention has communication holes and a porous structure. Furthermore, there is no skin layer on the outer surface, and the surface has excellent opening properties. Further, there is a void inside the fibril forming the communication hole, and at least a part of the void is opened on the fibril surface.
The outer surface opening ratio of the porous molded body of the present invention refers to the ratio of the sum of the opening areas of all the holes in the area of the field of view when the surface is observed with a scanning electron microscope. In the present invention, the surface of the molded body was observed at a magnification of 10,000 to actually measure the outer surface opening ratio.

The range of the surface opening ratio is preferably 10 to 90%, and particularly preferably 15 to 80%. If it is less than 10%, the diffusion rate of the adsorption target substances such as phosphorus and boron into the molded body becomes slow. On the other hand, if it exceeds 90%, the molded body has insufficient strength, and a molded body having excellent chemical strength is realized. Is difficult.
The outer surface opening diameter of the porous molded body of the present invention is determined by observing the surface with a scanning electron microscope. When the hole is circular, the diameter is used. When the hole is not circular, the equivalent circle diameter of a circle having the same area is used. A preferable range of the surface opening diameter is O.005 μm to 100 μm, and particularly preferably O.01 μm to 50 μm. If it is less than O.005 μm, the diffusion rate of substances to be adsorbed such as phosphorus and boron into the molded body tends to be slow, whereas if it exceeds 100 μm, the strength of the molded body tends to be insufficient.

The porous molded body of the present invention has voids inside the fibrils forming the communicating holes, and at least a part of the voids are opened on the surface of the fibrils. The inorganic ion adsorbent is supported on the outer surface of the fibril and the void surface inside the fibril. Since the fibril itself is also porous, an inorganic ion adsorbent that is an adsorption substrate embedded inside can also come into contact with an adsorption target substance such as phosphorus or boron, and can effectively function as an adsorbent. .
In the porous molded body of the present invention, since the portion where the adsorption substrate is supported is also porous, the fineness of the adsorption substrate, which was a disadvantage of the conventional method of kneading the adsorption substrate and the binder, The adsorption site is rarely clogged with a binder, and the adsorption substrate can be used effectively.

Here, the fibril means a fibrous structure made of an organic polymer resin and forming a three-dimensional continuous network structure on the outer surface and inside of the molded body. The void inside the fibril and the opening of the fibril surface are determined by observing the cut section of the molded body with a scanning electron microscope. It is observed that there are voids in the cross-section of the fibril and that the surface of the fibril is open. Furthermore, it is observed that the inorganic ion adsorbent powder is supported on the outer surface of the fibril and the inner void surface. The thickness of the fibril is preferably O.01 μm to 50 μm.
The pore diameter on the fibril surface is preferably O.001 μm to 5 μm.

The mechanism by which the structure of the porous molded body of the present invention is developed will be considered.
In general, a method of forming a porous body by immersing a mixture of a polymer and a good solvent of the polymer in a poor solvent and causing the polymer to gel by solvent exchange is called a wet phase separation method. In these processes, the proportion of the good solvent decreases, and microphase separation occurs accordingly, polymer spheres form, grow, entangle and form fibrils, and the fibril gaps become communication holes.
Further, the determination (solidification) of the compact structure proceeds sequentially from the outer surface to the inner part due to the diffusion of the poor solvent into the inner part. In this method, a dense layer called a skin layer is generally formed on the surface of the molded body.

  On the other hand, in the present invention, by adding a water-soluble polymer, which will be described later, the water-soluble polymer is dispersed between the polymer entanglements in the process of phase separation, so that the pores are mutually connected. In communication, the inside of the fibril becomes porous, and the fibril surface is also opened. Further, it is considered that a hole is formed on the outer surface of the molded body, and a molded body without a skin layer is obtained.

In addition, the water-soluble polymer partially dissolves in the poor solvent during the phase separation process, but a part remains in the fibril while being entangled with the molecular chain of the organic polymer resin. The remaining water-soluble polymer is considered to coat the gap between the adsorption substrate and the fibril which are inorganic ion adsorbents, and does not block the active site of the adsorption substrate. Therefore, the porous molded body of the present invention can use almost all of the adsorption capacity of the supported inorganic ion adsorbent, and has high efficiency.
Furthermore, since the water-soluble polymer partially extends its molecular chain from the surface of the fibril as if it were a beard, the surface of the fibril is kept hydrophilic, and an antifouling effect from hydrophobic adsorption can be expected.

In the porous molded body of the present invention, the communicating holes preferably have a maximum pore diameter layer in the vicinity of the surface of the molded body. Here, the maximum pore diameter layer means the largest portion in the pore diameter distribution of the communication holes extending from the surface of the molded body to the inside. In the case where there is a large circular or oval (finger-like) void called a void, the layer in which the void exists is called the maximum pore diameter layer.
The vicinity of the surface means the inner side up to 25% of the cleaved diameter of the molded body from the outer surface toward the center.
By having the maximum pore diameter layer in the vicinity of the surface of the molded body, it has the effect of accelerating the diffusion of the substance to be adsorbed into the interior. Therefore, adsorption target substances such as phosphorus and boron can be quickly taken into the molded body and removed from the treated water.
The positions of the maximum pore diameter and the maximum pore diameter layer are determined by observing the surface and the cut surface of the molded body with a scanning electron microscope.

As the hole diameter, when the hole is circular, the diameter thereof is used. When the hole is not circular, the equivalent circle diameter of a circle having the same area is used.
The form of the molded body can take any form such as a particulate form, a thread form, a sheet form, a hollow fiber form, a cylindrical form, and a hollow cylindrical form.
The method for forming the particulate molded body is not particularly limited, and examples thereof include a method in which a polymer solution is sprayed from a fluid nozzle and solidified in a coagulation bath.

In particular, the following rotating nozzle method is particularly preferable in that particles having a uniform particle size distribution can be obtained. The rotating nozzle method is a method in which a polymer solution (an organic polymer resin, a good solvent for the organic polymer resin, an inorganic ion adsorbent, a water This is a method of forming droplets by scattering a mixed slurry of a conductive polymer).
The diameter of the nozzle is preferably in the range of 0.1 mm to 10 mm, and more preferably in the range of 0.1 mm to 5 mm. If it is smaller than O.1 mm, the droplets tend not to scatter, and if it exceeds 10 mm, the particle size distribution tends to be wide.

  Centrifugal force is expressed in terms of centrifugal acceleration, preferably in the range of 5 to 1500 G, and more preferably in the range of 10 to 1000 G. More preferably, it is the range of 10-800G. When the centrifugal acceleration is less than 5G, the formation and scattering of droplets tend to be difficult, and when it exceeds 1000G, the polymer liquid is discharged in the form of a thread, and the particle size distribution tends to be widened.

The thread-like and sheet-like molded bodies can be obtained by extruding a polymer solution from a spinneret or die having a corresponding shape and solidifying it in a poor solvent. Moreover, a hollow fiber shaped molded product can be similarly molded by using a spinning nozzle composed of an annular orifice. When extruding the polymer stock solution from the spinning nozzle, the cylindrical and hollow cylindrical molded bodies may be solidified in a poor solvent while being cut, or may be solidified into a filament and then cut.
In particular, when the molded body is used as an adsorbent in the water treatment field, the particle shape is reduced in terms of pressure loss, effectiveness of contact area, and ease of handling when packed in a column or the like and passed through. Spherical particles (not only spherical but may be elliptical) may be particularly preferable.

  The average particle diameter of the spherical molded body of the present invention is a mode diameter (most frequent particle diameter) of a sphere equivalent diameter obtained from the angular distribution of scattered light intensity of diffraction by laser light, assuming that the particles are spherical. A preferable range of the average particle diameter is 100 to 2500 μm, particularly 200 to 2000 μm. If the average particle size is smaller than 100 μm, the pressure loss tends to increase when the column or tank is filled, and if the average particle size is larger than 2500 μm, the surface area when packed in the column or tank is reduced. Processing efficiency tends to decrease.

The porosity Pr (%) of the molded body of the present invention is the weight W1 (g) of the molded body when it contains water, the weight W0 (g) after drying, and the specific gravity of the molded body as ρ, The value represented by
Pr = (W1-WO) / (W1-WO + W0 / ρ) × 100
The wet weight may be determined by spreading a molded product sufficiently wet with water on dry filter paper and taking excess water before measuring the wet weight. Drying may be performed under vacuum at room temperature in order to eliminate moisture. The specific gravity of the molded body can be easily measured using a specific gravity bottle.
A preferable range of the porosity Pr (%) is 50% to 90%, and particularly preferably 60 to 85%. If it is less than 50%, the contact frequency between the adsorption target substance such as phosphorus and boron and the inorganic ion adsorbent as the adsorption substrate tends to be insufficient. If it exceeds 90%, the strength of the molded product tends to be insufficient.

The supported amount of the inorganic ion adsorbent in the molded product of the present invention is a value represented by the following formula when the weight Wd (g) when the molded product is dried and the weight Wa (g) of the ash content.
Load (%) = Wa / Wd × 100
Here, the ash content is the residue when the molded product of the present invention is baked at 800 ° C. for 2 hours.
A preferable loading range is 30 to 95%, more preferably 40 to 90%, and particularly preferably 65 to 90%. If it is less than 30%, the contact frequency between the adsorption target substance such as phosphorus and boron and the inorganic ion adsorbent as the adsorption substrate tends to be insufficient, and if it exceeds 95%, the strength of the molded product tends to be insufficient.
According to the method of the present invention, unlike the conventional attaching method, since the adsorbing substrate and the organic polymer resin are kneaded and molded, it is possible to obtain a molded body having a large carrying amount and strong strength.

The specific surface area of the molded product of the present invention is defined by the following formula.
Specific surface area (m ² / cm ³ ) = S _BET × Bulk specific gravity (g / cm ³ )
Here, S _BET is the specific surface area per unit weight of the molded body (m ² / g).
The specific surface area is measured using the BET method after vacuum drying the molded body at room temperature.
The bulk specific gravity is measured by measuring the apparent volume of a short shaped product such as a particle, a column, or a hollow column using a wet compact and a graduated cylinder. Then, it vacuum-drys at room temperature and calculates | requires weight.

For a long fiber-like, hollow fiber-like, or sheet-like shape, the cross-sectional area and length when wet are measured, and the volume is calculated from the product of both. Then, it vacuum-drys at room temperature and calculates | requires a weight.
The preferred range of the specific surface area is ^{5m 2 / cm 3 ~500m 2 /} cm 3. If it is less than 5 m ² / cm ^3, it exceeds tends 500m ² / cm ³ insufficient carrying amount and adsorption performance of the adsorption substrate, tends to lack the strength of the molded article.
In general, the adsorption performance (adsorption capacity) of an inorganic ion adsorbent that is an adsorption substrate is often proportional to the specific surface area. If the surface area per unit volume is small, the adsorption capacity and adsorption performance when packed in a column or tank are small, making it difficult to achieve high-speed processing.

  The molded body of the present invention has a three-dimensional network structure that is porous and intricately intertwined with fibrils. Furthermore, since the fibril itself has voids, it has a feature that the surface area is large. Since this has an adsorption substrate (inorganic ion adsorbent) having a larger specific surface area, the surface area per unit volume is also increased.

Next, the manufacturing method of the porous molded object of this invention is demonstrated.
The method for producing a porous molded body of the present invention is characterized in that an organic polymer resin, a good solvent thereof, an inorganic ion adsorbent, and a water-soluble polymer are mixed and then molded and solidified in a poor solvent. .
The organic polymer resin used in the present invention is not particularly limited, but is preferably one that can be made porous by wet phase separation. For example, polysulfone polymer, polyvinylidene fluoride polymer, polyvinylidene chloride polymer, acrylonitrile polymer, polymethyl methacrylate polymer, polyamide polymer, polyimide polymer, cellulose polymer, ethylene vinyl alcohol copolymer polymer, etc. There are many types.

In particular, ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile (PAN), polysulfone (PS), and polyvinylidene fluoride (PVDF) are preferable from the viewpoint of non-swelling property and biodegradability in water and ease of production. Furthermore, an ethylene vinyl alcohol copolymer (EVOH) is preferable because it has both hydrophilicity and chemical resistance.
In addition, the good solvent used in the present invention may be any as long as it dissolves both the organic polymer resin and the water-soluble polymer. For example, dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAC), dimethylformamide (DMF) and the like. These good solvents may be used alone or as a mixed solvent.

The content of the organic polymer resin in the good solvent is not particularly limited, but is preferably 5 to 40% by weight, and more preferably 7 to 30% by weight. If it is less than 5% by weight, it is difficult to obtain a strong molded product. When it exceeds 40% by weight, it is difficult to obtain a porous molded body having a high porosity.
The water-soluble polymer used in the present invention is not particularly limited as long as it is compatible with the organic polymer resin.
Examples of natural polymers include guar gum, locust bean gum, carrageenan, gum arabic, tragacanth, pectin, starch, dextrin, gelatin, casein, collagen and the like.

Examples of the semisynthetic polymer include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl starch, and methyl starch.
Furthermore, examples of the synthetic polymer include polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, sodium polyacrylate, and polyethylene glycols such as tetraethylene glycol and triethylene glycol.
Among these water-soluble polymers, a synthetic polymer is preferable in that it has biodegradability resistance.

In particular, it is particularly preferable to use polyvinylpyrrolidone as the water-soluble polymer because it has a high effect of developing a structure having voids inside the fibrils forming the communication holes as in the molded article of the present invention.
The weight average molecular weight of polyvinylpyrrolidone is preferably in the range of 2,000 to 2,000,000, more preferably in the range of 2,000 to 1,000,000, and still more preferably in the range of 2,000 to 100,000. If the weight average molecular weight is less than 2,000, the effect of developing a structure having voids inside the fibril tends to be low. If the weight average molecular weight exceeds 2,000,000, the viscosity at the time of molding increases, and molding is difficult. It tends to be difficult.

The content of the water-soluble polymer in the molded product of the present invention is expressed by the following equation when the weight of the molded product when dried is Wd (g) and the weight of the water-soluble polymer extracted from the molded product is Ws (g). The value represented.
Content (%) = Ws / Wd × 100
The content of the water-soluble polymer depends on the type and molecular weight of the water-soluble polymer, but is preferably 0.001 to 10%, and more preferably 0.01 to 1%. If it is less than 0.001%, the effect is not necessarily sufficient to open the surface of the molded body, and if it exceeds 10%, the polymer concentration becomes relatively thin and the strength may not be sufficient.

  Here, the weight Ws of the water-soluble polymer in the molded body is measured as follows. First, after the dried molded body is pulverized in a mortar or the like, the water-soluble polymer is extracted from the pulverized product using a good solvent for the water-soluble polymer, and then the extract is evaporated to dryness, The weight of the conducting polymer is determined. Furthermore, identification of the extracted evaporated and dried product and confirmation of the presence or absence of the water-soluble polymer remaining in the fibril and not extracted can be measured by infrared absorption spectrum (IR) or the like. Furthermore, when there is a water-soluble polymer that remains in the fibrils and is not extracted, the porous molded body of the present invention is dissolved in a good solvent for both the organic polymer resin and the water-soluble polymer, and then the inorganic ions are dissolved. A liquid obtained by removing the adsorbent by filtration can be prepared, and then the liquid can be analyzed using GPC or the like to quantify the content of the water-soluble polymer.

The content of the water-soluble polymer can be appropriately adjusted depending on the molecular weight of the water-soluble polymer and the combination of the organic polymer resin and the good solvent. For example, when a water-soluble polymer having a high molecular weight is used, the entanglement of the molecular chain with the organic polymer resin becomes strong, and it becomes difficult to move to the poor solvent side during molding, and the content can be increased.
The inorganic ion adsorbent referred to in the present invention refers to an inorganic substance exhibiting an ion adsorption phenomenon.

The inorganic ion adsorbent used in the present invention needs to contain at least one metal oxide represented by the following formula (I).
_{MN x O n · mH 2 O} (I)
(Wherein x is 0 to 3, n is 1 to 4, m is 0 to 6, and M and N are Ti, Zr, Sn, Sc, Y, La, Ce, Pr, Nd, Sm, Eu. Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Si, Cr, Co, Ga, Fe, Mn, Ni, V, Ge, Nb and Ta are metal elements selected from the group Are different from each other.)
The metal oxide as used in the present invention may be an unhydrated (non-hydrated) metal oxide in which m in the formula (I) can be represented by 0, or a hydrate (m can be represented by a numerical value other than 0). It may be a hydrous metal oxide.

The metal oxide in the case where x in formula (I) is a numerical value other than 0 is such that each contained metal element has regularity and is uniformly distributed throughout the oxide, for example, a perovskite structure, spinel It forms a structure and the like, and is contained in metal oxides such as nickel ferrite (NiFe ₂ O ₄ ) and zirconium hydrous ferrite (Zr · Fe ₂ O ₄ · mH ₂ O m is 0.5 to 6). It is a complex metal oxide represented by a chemical formula in which the composition ratio of each metal element is fixed.

The inorganic ion adsorbent supported on the porous molded body of the present invention is represented by the above formula (I) and has the following (a) to (a) to (a) to (a) to (a) to (a) It is preferable that it is a 1 type, or 2 or more types of mixture of the metal oxide chosen from the group in any one of c).
(A) hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated lanthanum oxide, and hydrated yttrium oxide (b) consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium A composite metal oxide of a metal element selected from the group and a metal element selected from the group consisting of aluminum, silicon, and iron (c) activated alumina

In addition, the metal oxide represented by the formula (I) used in the present invention may be a solid solution of metal elements other than M and N. For example, the hydrated zirconium oxide represented by the formula ZrO ₂ · mH ₂ O according to the formula (I) may be hydrated zirconium oxide in which iron is dissolved.
The inorganic ion adsorbent used in the present invention may contain a plurality of metal oxides represented by the formula (I). There are no particular restrictions on the distribution state of each metal oxide, but in order to obtain an inorganic ion adsorbent that has better cost performance by effectively utilizing the characteristics of each metal oxide, the surroundings of a specific metal oxide Is preferably a mixture structure covered with another metal oxide. An example of such a structure is a structure in which hydrated zirconium oxide covers the periphery of triiron tetroxide.

In addition, since the metal oxide referred to in the present invention includes a metal oxide in which other elements are dissolved, the hydrated zirconium oxide in which iron is dissolved in the surrounding area of triiron tetroxide in which zirconium is in solid solution. A covered structure can also be exemplified as a preferred example.
In the above example, hydrated zirconium oxide has high adsorption performance for ions such as phosphorus, boron, fluorine, arsenic and durability for repeated use, but is expensive. On the other hand, triiron tetroxide has a low adsorption performance for ions such as phosphorus, boron, fluorine, and arsenic and a durability performance for repeated use, but is very inexpensive.

  Therefore, when the structure around iron tetroxide is covered with hydrated zirconium oxide, the surface of the inorganic ion adsorbent that is involved in the adsorption of ions becomes hydrated zirconium oxide with high adsorption performance and durability. Since the inside which does not participate in adsorption becomes inexpensive iron trioxide, a porous molded body which can be used as an adsorbent having high adsorption performance, high durability performance and low cost, that is, excellent in cost performance is obtained.

In addition, for adsorption and removal of ions harmful to the environment and health of phosphorus, boron, fluorine, arsenic,
From the viewpoint of obtaining an adsorbent excellent in cost performance, the inorganic ion adsorbent used in the present invention is a metal element in which at least one of M and N in the formula (I) is selected from the group consisting of aluminum, silicon, and iron. A structure in which at least one of M and N in the formula (I) is covered with a metal oxide that is a metal element selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium. It is preferable to be configured.

  In this case, the content ratio of the metal element selected from the group consisting of aluminum, silicon, and iron in the inorganic ion adsorbent is a metal element selected from the group consisting of aluminum, silicon, and iron, and titanium, zirconium, tin, cerium, The total number of moles of the metal element selected from the group consisting of lanthanum and yttrium is T, the number of moles of the metal element selected from the group consisting of aluminum, silicon, and iron is F, and F / T (molar ratio) is 0.00. The range is preferably from 01 to 0.95, more preferably from 0.1 to 0.90, still more preferably from 0.2 to 0.85, and from 0.3 to 0.80. It is particularly preferred that When the value of F / T (molar ratio) is excessively increased, the adsorption performance and durability performance tend to be lowered.

Note that, depending on the metal, there are a plurality of forms of metal oxides having different oxidation numbers of the metal elements, but the form is not limited as long as it can exist stably in the inorganic ion adsorbent. For example, in the case of an iron oxide, hydrated ferric oxide (FeO _1.5 · mH ₂ O) or hydrated iron trioxide (FeO _1.33 · mH is preferably ₂ O).
In addition, the inorganic ion adsorbent of the present invention may contain an impurity element mixed due to its production method or the like within a range not departing from the achievement of the object of the present invention. Possible impurity elements to be mixed include nitrogen (nitrate, nitrite, ammonium), sodium, magnesium, sulfur, chlorine, potassium, calcium, copper, zinc, bromine, barium, hafnium, and the like.

In addition, since the specific surface area of the inorganic ion adsorbent affects the adsorption performance and durability, the specific surface area is preferably within a certain range. Specifically, it is preferable that a BET specific surface area determined by nitrogen adsorption method is 20~1000m ² / g, more preferably 30~800m ² / g, it is 50 to 600 m ² / g More preferably, it is 60-500 m < ² > / g. If the BET specific surface area is too small, the adsorption performance decreases, and if it is too large, the solubility in acids and alkalis increases, and as a result, the durability performance against repeated use decreases.

Next, a method for producing an inorganic ion adsorbent used in the present invention will be described taking as an example the case of producing an inorganic ion adsorbent having a structure in which zirconium oxide is covered around triiron tetroxide.
First, salts obtained by mixing a salt such as zirconium chloride, nitrate or sulfate with a salt such as iron chloride, nitrate or sulfate so that the above-mentioned F / T (molar ratio) is a desired value. Make an aqueous solution. Then, alkaline aqueous solution is added, pH is adjusted to 9, and a precipitate is produced | generated. Thereafter, the temperature of the aqueous solution is set to 50 ° C., air is blown in while maintaining the pH at 8.5 to 9, and oxidation treatment is performed until no ferrous ions can be detected in the liquid phase. The resulting precipitate is filtered off, washed with water and dried. The drying is performed by air drying or at about 150 ° C. or less, preferably about 90 ° C. or less for about 1 to 20 hours. The moisture content after drying is preferably in the range of about 6 to 30% by weight.

Zirconium oxychloride (ZrOC1 ₂ ), zirconium tetrachloride (ZrC1 ₄ ), zirconium nitrate (Zr (NO ₃ ) ₄ ), zirconium sulfate (Zr (SO ₄ ) ₂ ) Etc. These may be hydrated salts such as Zr (SO ₄ ) ₂ .4H ₂ O. These metal salts are usually used in the form of a solution of about 0.05 to 2.O moles per liter.
Examples of the iron salt used in the above-described production method include ferrous salts such as ferrous sulfate (FeSO ₄ ), ferrous nitrate (Fe (NO ₃ ) ₂ ), and ferrous chloride (FeC1 ₂ ). Can be mentioned. These may also be hydrated salts such as FeSO ₄ .7H ₂ O.

Examples of the alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, sodium carbonate and the like. These are preferably used in an aqueous solution of about 5-20% by weight.
When oxidizing gas is blown into the oxidation treatment, the time varies depending on the type of oxidizing gas and the like, but is usually about 1 to 10 hours. When an oxidizing agent is used for the oxidation treatment, for example, hydrogen peroxide, sodium hypochlorite, potassium hypochlorite and the like are used.

The inorganic ion adsorbent of the present invention is preferably as fine as possible, and its particle size is in the range of 0.01 to 100 μm, preferably 0.01 to 50 μm, more preferably 0.01 to 30 μm. .
If the particle size is smaller than 0.01 μm, the viscosity of the slurry at the time of production tends to increase and it tends to be difficult to mold. If it exceeds 100 μm, the specific surface area tends to be small, and the adsorption performance tends to be lowered.
The particle diameter here refers to the particle diameter of both the primary particles and the secondary particles in which the primary particles are aggregated or a mixture. The particle diameter of the inorganic ion adsorbent of the present invention is a sphere equivalent diameter (most frequent particle diameter) obtained from the angular distribution of scattered light intensity of diffraction by laser light.

  Examples of the poor solvent for the method of the present invention include liquids that do not dissolve organic polymer resins such as water, alcohols such as methanol and ethanol, ethers, and aliphatic hydrocarbons such as n-hexane and n-heptane. However, it is preferable to use water. It is also possible to control the coagulation rate by adding a little good solvent of the organic polymer resin in the poor solvent. The mixing ratio of the good solvent of the polymer resin and water is preferably O to 40%, and more preferably 0 to 30%. When the mixing ratio exceeds 40%, the coagulation rate becomes slow, so the polymer solution formed into droplets or the like is between the poor solvent and the molded product when entering the poor solvent and while moving in the poor solvent. The shape tends to be distorted by the influence of friction resistance.

  The temperature of the poor solvent is not particularly limited, but is preferably −30 ° C. to 90 ° C., more preferably O ° C. to 90 ° C., and further preferably 0 ° C. to 80 ° C. If the temperature of the poor solvent exceeds 90 ° C or is less than -30 ° C, the state of the molded body in the poor solvent is difficult to stabilize.

Next, an ion processing method using the porous molded body of the present invention as an adsorbent will be described.
The porous molded body of the present invention is suitable for use as an adsorbent for adsorbing and removing ions in water by contacting with a liquid.
Examples of liquids include drinking water, irrigation water, factory process water, river water, lake water, seawater, groundwater, sewage, factory wastewater, etc., activated sludge in sewage treatment plants and wastewater treatment facilities, thermal power plant desulfurization Examples include smoke treated water.

The ions to be adsorbed by the porous molded body of the present invention are not particularly limited to anions and cations. For example, with anions, phosphorus (phosphate ions), fluorine (fluoride ions), arsenic (arsenate ions, arsenite ions), boron (borate ions), iodine ions, chlorine ions, sulfate ions, nitrate ions , Nitrite ions, and ions of various organic acids such as acetic acid. Examples of the cation include sodium, potassium, calcium, cadmium, lead, chromium, cobalt, strontium, and cesium.
In particular, the inorganic ion adsorbent has a characteristic that shows specific selectivity for a specific ion, so that various ions such as sewage and industrial wastewater coexist, phosphorus, boron, fluorine, Suitable for removing ions such as arsenic.

When the porous molded body of the present invention is used as an adsorbent for water treatment applications, the porous molded body is usually used by being filled in a container, but the shape of the container and the shape of the packed layer of the porous molded body are As long as the porous molded body can be contacted with the water to be treated, there is no particular limitation. For example, a cylindrical, columnar, polygonal column, or box-shaped container is filled and used as a column, an adsorption tower, an adsorption tank, etc. Although it can be used, the high contact efficiency, which is a characteristic of the porous molded body, can be sufficiently extracted by filling the column or adsorption tower and passing the water to be treated through the liquid.
These containers are preferably provided with a solid-liquid separation mechanism that prevents the porous molded body from flowing out of the container, for example, installation of a pan and mesh.

The material of the container is not particularly limited, and examples include stainless steel, FRP (reinforced plastic with glass fiber), glass, and various plastics. In consideration of acid resistance, the inner surface may be made of rubber or fluororesin lining.
The contact method between the porous molded body and the water to be treated is not particularly limited as long as the porous molded body and the water to be treated can be brought into contact with each other. In the case where the packed bed of the porous molded body is a fixed bed, a method of passing water in an upward flow or a downward flow through the packed bed of a cylindrical, polygonal, box-shaped porous molded body,

  An external pressure system that allows water to flow from the outside in the circumferential direction to the inner cylinder through the packed layer of the cylindrical porous molded body, an internal pressure system that allows water to flow in the opposite direction, a system that allows water to flow horizontally through the box-shaped packed bed, etc. It can be illustrated. The packed bed of the porous molded body may be a fluidized bed system.

  In the ion processing method using the porous molded article of the present invention as an adsorbent, the desorption operation and activation operation described later are generally performed at the same site where the adsorption operation is performed. However, if there is not enough space at the site or the frequency of desorption is low, only the column can be removed from the apparatus and replaced with a new column separately. The removed column can be separately processed and reused in a factory equipped with a desorption and activation facility.

  When the porous molded body of the present invention is used as an adsorbent in water treatment applications, it is preferable to provide means for solid-liquid separation of suspended substances in water as a pretreatment. By removing suspended substances in water in advance, the surface of the porous molded body can be prevented from being blocked, and the adsorption performance of the porous molded body of the present invention can be sufficiently exhibited. Preferable solid-liquid separation means includes coagulation sedimentation, sedimentation separation, sand filtration, and membrane separation. In particular, a membrane separation technique that has a small installation area and that provides clear filtrate water is preferable. Preferred membrane separation techniques include reverse osmosis membrane (RO), ultrafiltration membrane (UF), microfiltration membrane (MF) and the like. The form of the membrane is not limited to flat membranes, hollow fibers, pleats, spirals, tubes and the like.

In the adsorption step of the present invention, it is preferable to adsorb the ions to be adsorbed after adjusting the pH of the liquid to a suitable pH by a combination of ions to be adsorbed and the inorganic ion adsorbent.
For example, the pH adjustment range when using an inorganic ion adsorbent having a structure in which phosphorus in a liquid is an object to be adsorbed and triiron tetroxide is covered with hydrated zirconium oxide is a range of pH 1.5 to 10, and Preferably, the pH is 2-7.
In addition, the pH adjustment range when using an inorganic ion adsorbent with a structure in which boron in the liquid is the target of adsorption and iron trioxide is covered with hydrated zirconium oxide or hydrated cerium oxide is pH 3 to 10. Yes, more preferably pH 5-8.

In addition, the pH adjustment range when using an inorganic ion adsorbent with a structure in which fluorine in the liquid is to be adsorbed and triiron tetroxide is covered with hydrated zirconium oxide or hydrated cerium oxide is in the range of pH 1-7. Yes, more preferably pH 2-5.
In addition, the pH adjustment range when using an inorganic ion adsorbent having a structure in which arsenic in a liquid is an object to be adsorbed and triiron tetroxide is covered with hydrated cerium oxide is a range of pH 3 to 12, more preferably PH 5-9.

  The porous molded body of the present invention can adsorb the anions again by contacting the alkaline aqueous solution to desorb the adsorbed anions and then treating the adsorbent with an acidic aqueous solution (re-applying). Use). By reusing the porous molded body, not only the cost can be reduced, but also the waste can be reduced. In particular, since the porous molded body of the present invention is excellent in durability, it is suitable for repeated use.

An anion can be eliminated when the pH of the alkaline solution is at least pH 10, but is preferably at least pH 12, more preferably at least pH 13. The alkali concentration is in the range of O.1 wt% to 30 wt%, more preferably in the range of 0.5 to 20 wt%. If it is thinner than O.1 wt%, the desorption efficiency is low, and if it is thicker than 30 wt%, the cost of alkali chemicals tends to increase.
The flow rate of the alkaline aqueous solution is not particularly limited, but is usually preferably in the range of SV0.5 to 15 (hr ⁻¹ ). When it is lower than SVO.5, the desorption time tends to be long and tends to be inefficient, and when it is larger than SV15, the contact time between the porous molded body and the alkaline aqueous solution is shortened, and the desorption efficiency tends to decrease. The type of the alkaline aqueous solution is not particularly limited, but usually, an inorganic alkali such as a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, and ammonium hydroxide, and organic amines are used. Of these, sodium hydroxide and potassium hydroxide are particularly preferred because of their high desorption efficiency.

In the desorption alkali recycling step and desorption ion recovery step in the present invention, an alkaline aqueous solution is brought into contact with the porous molded body of the present invention that has adsorbed ions, and ions are eluted in the alkaline solution. By adding a crystallization agent that generates ions and a precipitate and removing the precipitate, the alkali can be reused, and the ions can be recovered as a precipitate.
Examples of the crystallization agent include metal hydroxides. In the metal hydroxide, a metal salt combines with anions such as phosphorus, boron, fluorine, and arsenic to form a precipitate. Further, since the hydroxide becomes an alkali source of the desorption liquid, a closed system can be obtained by collecting and recycling the regenerated liquid. Specific examples include sodium hydroxide, aluminum hydroxide, magnesium hydroxide, and calcium hydroxide.

  From the viewpoint of obtaining a hardly soluble precipitate, that is, a precipitate having low solubility, a polyvalent metal hydroxide is preferable, and specifically, aluminum hydroxide, magnesium hydroxide, and calcium hydroxide are particularly preferable. In particular, calcium hydroxide is preferable in terms of cost.

For example, when fluorine is present as sodium fluoride in the eluent, high-concentration alkali can be recovered according to the following reaction formula.
2NaF + Ca (OH) ₂ → 2NaOH + CaF ₂ ↓
Similarly, when it exists as sodium phosphate, the alkali can be recovered according to the following reaction formula. Furthermore, the crystallized calcium phosphate can be recycled into fertilizers and the like.
6Na ₃ PO ₄ + 10Ca (OH) ₂ → 18NaOH + Ca10 (OH) ₂ (PO ₄ ) ₆ ↓
The addition amount of the metal hydroxide is not particularly limited, but is 1 to 4 times equivalent to the target ion. When the addition amount is equal to or less than the equimolar amount, the precipitation removal efficiency is low, and when it exceeds 4 times the equivalent, the removal efficiency hardly changes and tends to be economically disadvantageous.

  When removing the precipitate, the pH is preferably 6 or more. Further, considering that the aqueous alkaline solution is recovered and reused, it is preferably maintained at pH 12 or more, preferably pH 13 or more. If the pH during the precipitation process is lower than 6, the solubility of the precipitate increases and the precipitation efficiency decreases. When removing the precipitate, an inorganic flocculant such as aluminum sulfate or polyaluminum chloride or a polymer flocculant can be used in combination with the metal hydroxide.

The solid-liquid separation method of the precipitate in the eluent of the present invention is preferably a membrane separation method.
The membrane separation method is suitable for a closed system such as the present invention because it requires a small installation area and can obtain a clear filtered water.
The membrane separation method is not particularly limited, and examples thereof include an ultrafiltration membrane (UF), a microfiltration membrane (MF), and a dialysis membrane. The form of the membrane is not limited to a flat membrane, a hollow fiber, a pleat, a tube shape or the like. As a preferable membrane separation method, an ultrafiltration membrane (UF), a microfiltration membrane (MF) and the like are preferable in terms of filtration speed and filtration accuracy.

The porous molded body in the column after the desorption step is alkaline, and as it is, the ability to adsorb ions in the raw water again is low. Therefore, an operation of returning the pH in the column to a predetermined value using an acidic aqueous solution, that is, an activation treatment is performed.
The acidic aqueous solution is not particularly limited, but an aqueous solution such as sulfuric acid and hydrochloric acid is used. The concentration may be about O.001 to 10 wt%. If it is thinner than O.001 wt%, a large amount of water volume is required by the end of activation, and if it is thicker than 10 wt%, there is a possibility that a problem may occur in terms of danger in handling an acidic aqueous solution.

The liquid passing speed is not particularly limited, but is usually preferably in the range of SV 0.5 to 30 (hr ⁻¹ ). If it is lower than SV0.5, the activation time tends to be long and inefficient, and if it is larger than SV30, the contact time between the porous molded body and the acidic aqueous solution becomes short, and the activation efficiency tends to decrease. is there.
A more preferable method in the activation method is to circulate the active solution between the column and the pH adjusting tank.
By adopting this configuration, the pH of the porous molded body in the column shifted to the alkali side by the desorption operation can be slowly returned to a predetermined pH in consideration of the acid resistance of the inorganic ion adsorbent.

For example, it is known that iron oxide is remarkably dissolved by acid at pH 3 or lower. When such iron oxide is supported on a porous molded body, the conventional activation method has a problem of dissolution of iron, and therefore, there is only a method of treating with a thin acid having a pH of 3 or more. However, this method requires a large volume of water and is not economically acceptable.
In contrast to such conventional techniques, the activation method of the present invention is provided with a column and a pH adjusting tank and circulates the activation liquid. Therefore, the activation method can be activated while avoiding the pH range in which it is dissolved by an acid. The volume of water used for conversion can be reduced, and the apparatus can be made compact.
The liquid passing speed at this time is usually selected in the range of SV1 to 200 (hr ⁻¹ ). More preferably, it is in the range of SV1O-100. If it is lower than SV1, the activation time tends to be long and tends to be inefficient, and if it is larger than SV200, a large pump movement is required and tends to be inefficient.

This series of desorption and activation operations can be performed while the column is filled with the adsorbent. That is, regeneration can be easily performed by passing an alkaline aqueous solution and an acidic aqueous solution sequentially through the column after the adsorption operation is completed in the column packed with the adsorbent. In this case, the liquid flow direction may be either an upward flow or a downward flow.
Since the porous molded article of the present invention is excellent in chemical resistance and strength, the ion adsorption performance is hardly lowered even if this regeneration treatment is repeated several tens to several hundreds of times.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these.
In the examples, various physical properties of the molded bodies were measured by the following methods.
-Observation of molded body with scanning electron microscope The molded body was observed with a scanning electron microscope (SEM) using an S-800 scanning electron microscope manufactured by Meidari Seisakusho.
-Cleaving of the molded body The molded body was vacuum-dried at room temperature, and the dried molded body was added to isopropyl alcohol (IPA) to impregnate the molded body with IPA. Next, the molded body was enclosed with IPA in a gelatin capsule having a diameter of 5 mm and frozen in liquid nitrogen. The frozen molded body was cleaved together with the engraved sword. The cut molded body was selected as a microscope sample.

-Surface aperture ratio An image of the surface of the molded body photographed using a scanning electron microscope was obtained using image analysis software (Win Roof (trade name) manufactured by Mitani Corporation). In more detail, the obtained SEM image is recognized as a grayscale image, and the threshold is manually adjusted by dividing the dark portion into an opening and the light portion as a fibril, and dividing it into an opening portion and a fibril portion. Then, the area ratio was obtained. -Aperture diameter of the surface It was obtained by actual measurement from the image of the surface of the molded body taken using a scanning electron microscope. When the hole was circular, the diameter was used. When the hole was not circular, the equivalent circle diameter of a circle having the same area was used.

-Particle size The particle size of the compact and inorganic ion adsorbent was measured with a laser diffraction / scattering particle size distribution analyzer (LA-910 (trade name) manufactured by HORIBA). However, when the particle size was 1 or more than OOO μm, the longest diameter and the shortest diameter of the molded body were measured using an SEM image, and the average value was taken as the particle size.
-Porosity A molded product that had been sufficiently wetted with water was spread on a dry filter paper, and after removing excess water, the weight was measured to obtain the weight (W1) of the molded product when it contained water. Next, the molded body was vacuum-dried at room temperature for 24 hours to obtain a dried molded body. The weight of the dried molded body was measured and taken as the weight (W0) when the molded body was dried.

Next, a specific gravity bottle (Geryusac type, capacity 10 m1) was prepared, and the weight when the specific gravity bottle was filled with pure water (25 ° C.) was measured to obtain the weight at the time of full water (Ww). Next, a molded body wet in pure water was placed in this specific gravity bottle, and the weight was measured by filling the marked water with pure water to obtain (Wwm). Next, the molded body was taken out from the specific gravity bottle and subjected to vacuum drying at room temperature for 24 hours to obtain a dried molded body. The weight of the dried molded body was measured and determined as (M).
The specific gravity (ρ) and porosity (Pr) of the molded body were determined according to the following calculation formula.
ρ = M / (Ww + M-Wwm)
Pr = (W1-W0) / (W1-W0 + W0 / ρ) × 100
In the formula, Pr is the porosity (%), W1 is the weight (g) of the molded body when it is wet, WO is the weight (g) after drying the molded body, and ρ is the specific gravity (g / cm ³ ), M is the weight of the molded body after drying (g), Ww is the weight when the specific gravity bottle is full (g), and Wwm is the weight of the specific gravity bottle when water and the pure water are added ( g).

-Loading amount The molded body was dried at room temperature by vacuum drying for 24 hours to obtain a dried molded body. The weight of the dried molded body was measured and used as the weight Wd (g) when the molded body was dried. Next, the dried molded body was calcined at 800 ° C. for 2 hours using an electric furnace, and the weight of ash was measured to obtain the weight of ash Wa (g). The supported amount was determined from the following formula.
Load (%) = Wa / Wd x 100
In the formula, Wa is the weight (g) of the ash content of the molded body, and Wd is the weight (g) when the molded body is dried.

・ Specific surface area (m ² / cm ³ )
After the molded body was vacuum-dried at room temperature, the specific surface area S _BET (m ² / g) of the porous molded body was determined by the BET method using Beckman Coulter Co., Ltd. Coulter SA3100 (trade name).
Next, the apparent volume V (cm ³ ) of the wet compact was measured using a graduated cylinder or the like. Thereafter, vacuum drying is performed at room temperature to determine the weight W (g).
The specific surface area of the molded product of the present invention was determined from the following equation.
Specific surface area (m ² / cm ³ ) = S _BET × Bulk specific gravity (g / cm ³ )
Bulk specific gravity (g / cm ³ ) = W / V
In the formula, SS _BET is the specific surface area (m ² / g) of the molded body, W is the dry weight (g) of the molded body, and V is the apparent volume (cm ³ ).

・ Phosphorus concentration measurement
Phosphorus concentration was measured using a phosphoric acid measuring device Phosfax Compact (trade name) manufactured by HACH.

(Production Example) Production of inorganic ion adsorbent powder One liter of an O.15 molar aqueous solution of zirconium oxychloride (ZrOC1 ₂ ) was prepared. This solution contained 13.7 g of metal ions as zirconium. In this aqueous solution, 84.Og of ferrous sulfate crystals (FeSO ₄ · 7H ₂ O) was added and dissolved while stirring. This amount corresponds to 0.3 mol of iron ion (F / T (molar ratio) 0.67). Next, when a 15% by weight sodium hydroxide solution was added dropwise to the aqueous solution while stirring until the pH of the solution reached 9, a blue-green precipitate was formed. Next, air was blown in at a flow rate of 10 liters / hour while the aqueous solution was heated to 50 ° C. When the air blowing was continued, the pH of the aqueous solution was lowered. In this case, a 15 wt% sodium hydroxide solution was dropped to maintain the pH at 8.5-9. When the blowing of air was continued until no ferrous ions could be detected in the liquid phase by spectrophotometric analysis, a black precipitate was formed. The black precipitate was then filtered off with suction, washed with deionized water until the filtrate was neutral, and dried at 70 ° C. or lower. This was pulverized with a ball mill for 7 hours to obtain a powder having an average particle size of 2.8 μm. The BET specific surface area of this powder was 170 m ² / g.

When this powder was analyzed by X-ray diffraction analysis, only a peak derived from iron trioxide (FeO _1.33 magnetite) was confirmed.
In addition, the results of observation and elemental analysis of the powder before ball milling using a transmission electron microscope (TEM-EDX) equipped with an elemental analyzer are shown in FIGS.
FIG. 1 is a TEM image of the powder. It was observed that the rods and particles that look blackish were covered with haze. 2 is the same as FIG. 1 to 3 show the results of elemental analysis shown in FIG. The elemental analysis result of the location shown by 4-6 was shown.

Aluminum and copper detected by elemental analysis are elements derived from a mesh that supports a TEM column and an observation sample, and are not elements derived from the sample.
No. Iron was strongly detected from the rod-like and granular materials shown in 1, 4, 5, and 6, and zirconium was a trace amount even when detected. On the other hand, no. Zirconium was strongly detected from the haze that existed around the rod-like and granular materials shown in 2 and 3, and iron was detected in a trace amount even when it was detected.
From the observation and analysis results with a transmission electron microscope equipped with the above X-ray diffraction analysis and elemental analysis equipment, the structure of the obtained powder is around the iron oxide (possibly containing zirconium in solid solution). It was determined that the structure covered with hydrated zirconium oxide (possibly in solid solution of iron).

(Example)
Ethylene vinyl alcohol copolymer (EVOH, Nippon Synthetic Chemical Industry Co., Ltd., Soarnol E3803 (trade name)) 10 g, Polyvinylpyrrolidone (PVP, BASF Japan Ltd., Luvitec K30 Powder (trade name)) 10 g, Dimethyl sulfoxide ( DMSO, Kanto Chemical Co., Ltd. (80 g) was dissolved by heating to 60 ° C. in a Separa flask to obtain a uniform polymer solution. To 100 g of this polymer solution, 95 g of the inorganic ion adsorbent powder prepared in the production example was added and mixed well to obtain a slurry.
The obtained composite polymer slurry was heated to 40 ° C., and supplied to the inside of a cylindrical rotating container having a nozzle with a diameter of 5 mm on the side surface. The container was rotated, and droplets were discharged from the nozzle by centrifugal force (15 G). Was discharged into a coagulation bath made of water at 60 ° C. to coagulate the composite polymer slurry. Further, washing and classification were performed to obtain a spherical molded body having an average particle diameter of 645 μm.

This spherical porous molded body had a porosity of 80%, a surface opening diameter of 0.1 to 10 μm, a loading amount of 82%, a surface opening ratio of 56%, and a specific surface area of 65 m 2 / cm 3.
Furthermore, when the surface and fractured surface of the obtained porous molded body were observed using a scanning electron microscope (SEM), the presence of a skin layer was not observed. In addition, a maximum pore diameter layer (void layer) was observed near the surface, and voids inside the fibril and pores on the fibril surface were also confirmed. Furthermore, it was observed that the inorganic ion adsorbent powder was supported on the outer surface of the fibril and the void surface inside the fibril.

Next, this porous molded body was subjected to a phosphorus adsorption test under the following conditions.
Dissolve trisodium phosphate (Na ₃ PO ₄ · 12H ₂ O) in distilled water to make a solution with a phosphorus concentration of 9 mg-P / liter, and adjust the pH to 7 with sulfuric acid as the model solution, that is, the adsorption stock solution did.
The obtained porous molded body (8 ml) was packed in a column (inner diameter: 10 mm), and the previous adsorption stock solution was passed through at a rate of 240 ml / hr (SV30). Sampling the effluent (treatment liquid) from the column every 30 minutes, measuring the phosphate ion concentration (phosphorus concentration) in the treated water, and the amount of water flow until 0.5 mg-P / liter (ppm) is exceeded (Adsorption amount) was determined.

After the above adsorption operation, it was immersed in a 7 wt% sodium hydroxide aqueous solution for 2 hours to desorb the adsorbed phosphoric acid, and then washed with distilled water. Next, regeneration was performed by immersing in an O.1 wt% sulfuric acid aqueous solution for 5 hours. Next, it was washed again with distilled water.
The above adsorption, desorption and regeneration operations were repeated 50 times, and the amount of adsorption at the first and 50th times and the rate of change were examined.

The adsorption rate change rate is expressed by the following equation.
Adsorption amount change rate = (50th adsorption amount) / (1st adsorption amount) × 100
As a result, the first adsorption amount is 940 mg-P / L-adsorbent, the 50th adsorption amount is 910 mg-P / L-adsorbent, and the adsorption amount change rate is 97%. The durability of this adsorbent was confirmed.

  The porous molded body of the present invention can be suitably used as an adsorbent that selectively adsorbs and removes phosphorus, boron, arsenic, fluorine ions and the like contained in river water, sewage treated water, and factory effluent.

The transmission electron micrograph of the hydrated oxide powder of the zirconium obtained by the manufacture example, and iron. In FIG. The elemental analysis result of the location shown by 1-3. In FIG. The elemental analysis result of the location shown by 4-6.

Claims (11)

A porous molded body having a communicating hole that opens to the outer surface, comprising an organic polymer resin and an inorganic ion adsorbent,
The inorganic ion adsorbent contains at least one metal oxide represented by the following formula (I):
And there is a void inside the fibril forming the communication hole, and at least a part of the void is open on the surface of the fibril, and the inorganic ion adsorbent on the outer surface of the fibril and the surface of the void inside Is a porous molded body characterized in that is supported.
_{MN x O n · mH 2 O} (I)
(Wherein x is 0 to 3, n is 1 to 4, m is 0 to 6, and M and N are Ti, Zr, Sn, Sc, Y, La, Ce, Pr, Nd, Sm, Eu. Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Si, Cr, Co, Ga, Fe, Mn, Ni, V, Ge, Nb and Ta are metal elements selected from the group Are different from each other.) 2. The porous material according to claim 1, wherein the metal oxide represented by the formula (I) is one or more selected from the group of any of the following (a) to (c). Molded product.
(A) hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated lanthanum oxide, and hydrated yttrium oxide (b) consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium A composite metal oxide of a metal element selected from the group and a metal element selected from the group consisting of aluminum, silicon, and iron (c) activated alumina   The porous molded body according to claim 1 or 2, wherein the inorganic ion adsorbent contains a plurality of types of metal oxides represented by formula (I).   The inorganic ion adsorbent has a structure in which the metal oxide (A) represented by the formula (I) is covered with another metal oxide (B) represented by the formula (I). The porous molded body according to claim 3.   The metal oxide (A) is an oxide in which at least one of M and N in the formula (I) is a metal element selected from the group consisting of aluminum, silicon, and iron, and the metal oxide (B) 5. The porous molding according to claim 4, wherein at least one of M and N in the formula (I) is an oxide of a metal element selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium, or activated alumina. body.   The porous molded body according to any one of claims 1 to 5, wherein the communication hole has a maximum pore diameter layer near the surface of the molded body.   The porous molded body according to any one of claims 1 to 6, which has an average particle diameter of 100 to 2500 µm and is substantially spherical.   The porous molded body contains at least one selected from the group consisting of ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile (PAN), polysulfone (PS), and polyvinylidene fluoride (PVDF) as an organic polymer resin. The porous molded body according to any one of claims 1 to 7. In a method for producing a porous molded article comprising an organic polymer resin and an inorganic ion adsorbent,
As the inorganic ion adsorbent, an inorganic ion adsorbent containing at least one metal oxide represented by the formula (I) is used,
A method for producing a porous molded body, which comprises mixing an organic polymer resin, a good solvent for the organic polymer resin, the inorganic ion adsorbent, and a water-soluble polymer, followed by molding and solidifying in a poor solvent.   An inorganic ion adsorbent comprising a structure in which the metal oxide (B) covers the metal oxide (A).   The metal oxide (A) is an oxide in which at least one of M and N in the formula (I) is a metal element selected from the group consisting of aluminum, silicon, and iron, and the metal oxide (B) The inorganic ion adsorbent according to claim 10, wherein at least one of M and N in formula (I) is an oxide of a metal element selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium, or activated alumina. .