JP2009297707A - High adsorbent porous shaped article and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous shaped article appropriate as a sorbent medium, which is capable of adsorb and remove low-concentration phosphorus, boron, fluorine, arsenic, and the like contained in sewage or drainage at high speed and has large adsorption capacity. <P>SOLUTION: The porous shaped article comprises an organic polymer resin and an inorganic ion adsorbent, wherein the ratio of 95% cumulative relative X-ray intensity to 5% cumulative relative X-ray intensity (cumulative relative X-ray intensity ratio) of ingredient elements composing an inorganic ion adsorbent that is supported by the porous article ranges from 1 to 10 as measured using an electron probe microanalyzer (EPMA). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a porous article having high adsorption performance and a method for producing the same. Particularly suitable for adsorbents that selectively adsorb and remove phosphorus, boron, arsenic, and fluorine ions contained in river water, sewage treated water, and factory effluent, and have a high treatment speed and a large adsorption capacity. It is about.

In recent years, environmental standards such as phosphorus, boron, arsenic and fluoride ions in drinking water, industrial water, industrial wastewater, sewage treated water, environmental water have been strengthened due to problems of environmental pollution and eutrophication, and technology to remove them has been developed. 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 feared to be depleted, and there is a need for a technique for recovering it from wastewater and reusing 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 plaque 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.

  As a conventional technique for removing these harmful substances, an adsorbent in which an inorganic ion adsorbent powder such as zirconium hydroferrite or hydrous cerium hydroxide is supported on a polymer material is known (see Patent Document 1). ). This known adsorbent is porous and has a high surface pore-opening property, and is excellent in adsorption performance because diffusion of an object to be adsorbed such as phosphorus or boron into the adsorbent is quick. In this molded body, a powdered inorganic ion adsorbent is mixed with a binder organic polymer, a good solvent for the organic polymer, and further a water-soluble polymer to obtain a raw material slurry. It is produced by a method of solidifying by contacting with a poor solvent such as

  However, in the conventional production method, since a polymer solution in which an organic polymer and a water-soluble polymer are dissolved in an organic solvent has a high viscosity, it is difficult to uniformly disperse the inorganic ion adsorbent in the polymer solution. there were. In fact, secondary aggregates of inorganic ion adsorbents are observed inside the porous molded body molded with insufficient dispersion, and the total amount of inorganic ion adsorbents charged in the preparation is not effectively reflected in the adsorption performance. Had problems.

WO2005 / 056175

  The present invention is capable of adsorbing and removing low concentrations of phosphorus, boron, fluorine, arsenic, etc. contained in water and wastewater at high speed, and has a large adsorption capacity and high durability, and is suitable for an adsorbent that can be used repeatedly. It aims at providing a property molded object and its manufacturing method.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors found that the water-soluble polymer is inorganic when the inorganic ion adsorbent is uniformly mixed in the organic solvent in the process of producing the raw slurry. In addition to dispersing as an ion adsorbent, by adopting a manufacturing method that uses pulverization / mixing means such as a bead mill, secondary aggregates of inorganic ion adsorbents are formed in the porous molded body after molding. The inventors have found that a porous molded body having a small amount and excellent adsorption performance can be obtained, and have reached the present invention based on this finding.

That is, the present invention is as follows.
(1) A porous molded body comprising an organic polymer resin and an inorganic ion adsorbent, which is obtained by using an electron beam microanalyzer (EPMA) and is supported on the porous molded body. The said porous molded object including the ratio (relative cumulative X-ray intensity ratio) of 95% relative cumulative X-ray intensity and 5% relative cumulative X-ray intensity of the component elements constituting the ion adsorbent being 1-10.
(2) The porous molded body has voids in the fibrils forming the communication holes, and at least a part of the voids are open on the surface of the fibrils, and the outer surface and the inner surface of the fibrils. The porous molded body according to the above (1), wherein an inorganic ion adsorbent is supported on the surface of the void.
(3) The porous molded body according to (1) or (2), wherein the communication hole has a maximum pore diameter layer near the surface of the molded body.
(4) The porous molded body according to any one of (1) to (3), wherein the average particle diameter is 100 to 2500 μm.
(5) The organic polymer resin comprises one or more selected from the group consisting of ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile (PAN), polysulfone (PS), and polyvinylidene fluoride (PVDF). The porous molded body according to any one of (1) to (4) above.
(6) The porous molded body according to (1) to (5) above, wherein the inorganic ion adsorbent contains 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.)
(7) The porous molded body according to (6), wherein the metal oxide is one or a mixture of two or more selected from the following groups (a) to (c).
(A) hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated lanthanum oxide, and hydrated yttrium oxide (b) composed 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 (8) the inorganic ion adsorbent is activated alumina loaded with aluminum sulfate, and The porous molded body according to any one of the above (1) to (5), comprising at least one selected from the group consisting of aluminum sulfate impregnated activated carbon.
(9) The porous molded body according to any one of (1) to (8), wherein the supported amount of the inorganic ion adsorbent is 65 to 95%.
(10) The porous molded body according to any one of (2) to (9), wherein the fibril comprises an organic polymer resin, an inorganic ion adsorbent, and a water-soluble polymer.
(11) The porous molded article according to (10), wherein the water-soluble polymer is a synthetic polymer.
(12) The porous molded body according to (10) or (11), wherein the water-soluble polymer is polyvinylpyrrolidone.
(13) The porous molded body according to any one of (10) to (12), wherein the content of the water-soluble polymer is 0.001 to 10%.
(14) A column packed with the porous molded body according to any one of (1) to (13) above.
(15) A method for producing a porous molded article comprising an organic polymer resin and an inorganic ion adsorbent, wherein (1) at least a good solvent of the organic polymer resin, an inorganic ion adsorbent, and a water-soluble polymer 3 A pulverization / mixing step for obtaining a slurry by pulverizing / mixing seeds using a pulverizing / mixing means, (2) a dissolving step for dissolving the organic polymer resin in the slurry obtained in step (1), (3) step (2 A method for producing a porous molded body, comprising a molding step in which the slurry obtained in (1) is molded and solidified in a poor solvent.
(16) The method according to 15) above, wherein the pulverization / mixing means is a medium stirring mill.
(17) The good solvent of the organic polymer resin is one or more selected from the group consisting of dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAC), and dimethylformamide (DMF). The method according to any one of (15) to (16) above.
(18) The method according to any one of (15) to (17), wherein the poor solvent is water or a mixture of a good solvent for organic polymer resin and water.
(19) The method according to any one of (15) to (18) above, wherein a mixing ratio of a good solvent of the organic polymer resin and a mixture of water is 0 to 40%.
(20) A molding method is to spray a slurry in which an organic polymer resin, a good solvent of the organic polymer resin, a water-soluble polymer, and an inorganic ion adsorbent are mixed from a nozzle provided on a side surface of a rotating container. The method according to any one of (15) to (19), which comprises forming a droplet.
(21) A porous adsorbent comprising the porous molded body according to any one of (1) to (13) above.

Since the porous molded body of the present invention has few secondary aggregates of inorganic ion adsorbents in the molded body, all of the inorganic ion adsorbents used in the preparation are uniformly dispersed throughout the molded body. Since it is effectively involved in adsorption, the contact efficiency with the substance to be adsorbed is extremely high.
Moreover, since there are few secondary aggregates of an inorganic ion adsorption body, since secondary aggregates have few cracks from the starting point, durability is also high.
Therefore, water and wastewater containing low concentrations of phosphorus, boron, fluorine, arsenic, etc. can be suitably treated.

4 is an electron micrograph (magnification 200 times) showing a cut section of the molded body of Example 1. FIG. The electron micrograph which shows the crack surface surface vicinity of the molded object of Example 1 (500-times multiplication factor). The electron micrograph which shows the outer surface of the molded object of Example 1 (magnification 10,000 times). 4 is an electron micrograph (magnification 10,000 times) showing a fractured section of the molded body of Example 1. FIG. The electron micrograph (150-times multiplication factor) which shows the crack surface of the molded object of the comparative example 1. FIG. The electron micrograph which shows the crack surface surface vicinity of the molded object of the comparative example 1 (500-times multiplication factor). The electron micrograph which shows the outer surface of the molded object of the comparative example 1 (magnification 10,000 times). 4 is an electron micrograph (magnification 10,000 times) showing a cut section of a molded body of Comparative Example 1. FIG.

Hereinafter, the present invention will be specifically described focusing on its preferred form.
First, the structure of the molded body of the present invention will be described.
In the porous molded body of the present invention, an inorganic ion adsorbent is supported on a porous molded body made of an organic polymer resin.
The inorganic ion adsorbent obtained by analyzing with an electron beam microanalyzer (EPMA) in the distribution state of the inorganic ion adsorbent in the inorganic ion adsorbent formed on the porous molded body of the present invention. In the concentration distribution of component elements constituting the component element, the ratio of the 95% relative cumulative X-ray intensity to the 5% relative cumulative X-ray intensity (relative cumulative X-ray intensity ratio) of the component elements is 1-10. A more preferable range of the relative cumulative X-ray intensity ratio is 1 to 7, more preferably 1 to 5.
In the analysis method of the distribution state of the inorganic ion adsorbent in the molded body of the inorganic ion adsorbent, surface analysis is performed using an electron beam microanalyzer (EPMA). The surface analysis data obtained by this analysis, specifically, the frequency distribution of the X-ray intensity (count number) is statistically processed.
The 5% relative cumulative X-ray intensity is small in the frequency distribution of the X-ray intensity of the component elements constituting the inorganic ion adsorbent, which was obtained by surface analysis of the cut surface of the molded body with an electron beam microanalyzer (EPMA). The X-ray intensity value is accumulated from the X-ray intensity (low concentration) side, and the accumulated X-ray intensity frequency reaches 5%.
Similarly, the 95% relative cumulative X-ray intensity is the frequency distribution of the X-ray intensity of the component elements constituting the inorganic ion adsorbent, which was obtained by surface analysis of the cut surface of the molded body with an electron beam microanalyzer (EPMA). Is the value of the X-ray intensity at which the cumulative X-ray intensity frequency reaches 95%. Using the 95% relative cumulative X-ray intensity and the 5% relative cumulative X-ray intensity thus determined, the relative cumulative X-ray intensity ratio was determined from the following formula.
Relative cumulative X-ray intensity ratio = 95% relative cumulative X-ray intensity / 5% relative cumulative X-ray intensity

This relative cumulative X-ray intensity ratio indicates the dispersion state of the inorganic ion adsorbent in the molded body of the inorganic ion adsorbent. When the relative cumulative X-ray intensity ratio is 10 or less, the dispersion state of the inorganic ion adsorbent in the porous molded body of the inorganic ion adsorbent is good, and there are few secondary aggregates called so-called lumps. Therefore, the contact efficiency between the inorganic ion adsorbent and the ions to be adsorbed is increased, and the adsorption performance is kept good.
Furthermore, since there are few secondary aggregates of an inorganic ion adsorption body, since it is few that a secondary aggregate breaks from a starting point, durability is also high.

The molded body of the present invention preferably has the following special porous structure.
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 inorganic ion adsorbent is supported on the outer surface of the fibril and the inner void surface.
The outer surface aperture ratio of the molded article of the present invention refers to the ratio of the sum of the aperture 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. An electron micrograph of the outer surface of the porous molded body of the present invention is shown in FIG.

The range of the surface opening ratio is preferably 10 to 90%, particularly preferably 15 to 80%. If it is 10% or more, a decrease in the diffusion rate of the substance to be adsorbed such as phosphorus or boron into the molded body is suppressed, while if it is 90% or less, the molded body has sufficient strength and has excellent mechanical strength. Realization is possible.
The outer surface opening diameter of the 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.
The range of the surface opening diameter is preferably 0.005 μm to 100 μm, and particularly preferably 0.01 μm to 50 μm. When the thickness is 0.005 μm or more, a decrease in the diffusion rate of a substance to be adsorbed such as phosphorus or boron into the molded body is suppressed. On the other hand, when the thickness is 100 μm or less, the strength of the molded body is sufficient.

The molded body of the present invention has voids in the fibrils forming the communication 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 a substance to be adsorbed 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 an inorganic ion adsorbent that is an 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. FIG. 4 is an electron micrograph obtained by observing the fractured surface of the porous molded body of the present invention at a magnification of 10,000 times. 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 is supported on the outer surface of the fibril and the inner void surface.
The thickness of the fibril is preferably 0.01 μm to 50 μm.
The pore diameter on the fibril surface is preferably 0.001 μm to 5 μm.

The mechanism by which the structure of the molded body of the present invention is developed will be considered below.
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 molded body having an opening on the outer surface of the molded body and having no skin layer can be 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 is 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. When there is a large circular or oval (finger-shaped) 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 as the 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 molding method of the particulate molded body is not particularly limited, but the polymer slurry (organic polymer resin, good solvent of the organic polymer resin, water-soluble polymer, inorganic ion, and the like can be obtained from one fluid nozzle or two fluid nozzle. There is a method in which the adsorbent mixed slurry) is sprayed and coagulated 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 of forming droplets by scattering polymer slurry from a nozzle provided on a side surface of a rotating container rotating at high speed by centrifugal force.
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. When the thickness is 0.1 mm or more, the droplets are likely to scatter, and when the thickness is 10 mm or less, the spread of the particle size distribution can be suppressed.

Centrifugal force is expressed by centrifugal acceleration and is preferably in the range of 5 to 1500 G, more preferably in the range of 10 to 1000 G. More preferably, it is the range of 10-800G. When the centrifugal acceleration is 5G or more, the formation and scattering of droplets are easy, and when the centrifugal acceleration is 1500G or less, the polymer slurry is discharged without being in the form of a thread, so that the particle size distribution can be suppressed from widening.
The thread-like and sheet-like molded bodies can be obtained by extruding a polymer slurry from a spinneret or a 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 slurry 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 thread and then cut later.
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 the contact area and ease of handling when packed in a column or the like and passed through. Spherical particles (not only true spheres but also oval spheres) are particularly preferable.
The average particle diameter of the spherical molded body of the present invention is the median diameter of the sphere equivalent diameter obtained from the angle distribution of the scattered light intensity of diffraction by laser light, assuming that the particles are spherical. The range of a preferable average particle diameter is 100-2500 micrometers, and 200-2000 micrometers is especially preferable. When the average particle size is 100 μm or more, pressure loss is suppressed when the column or tank is packed into a column or tank, and when the average particle size is 2500 μm or less, the surface area when the column or tank is packed is increased and the processing efficiency is increased. .

The porosity Pr (%) of the molded body of the present invention is the following formula when 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 is ρ. The value represented by
Pr = (W1-W0) / (W1-W0 + W0 / ρ) × 100
The wet weight may be determined by spreading a molded product sufficiently wet with water on dry filter paper and removing excess moisture 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 50% or more, the contact frequency between the substance to be adsorbed such as phosphorus and boron and the inorganic ion adsorbent as the adsorption substrate becomes sufficient. If it is 90% or less, the strength of the molded article is sufficient.

The supported amount of the inorganic ion adsorbent in the molded body of the present invention is a value represented by the following formula when the weight Wd (g) when the molded body is dried and the weight Wa (g) of ash.
Load (%) = Wa / Wd × 100
Here, the ash content is the residue when the molded article of the present invention is baked at 800 ° C. for 2 hours.
In order to obtain a porous molded body having high adsorption performance, it is preferable to increase the amount of the inorganic ion adsorbent supported. However, if it is too high, the strength of the molded product tends to be insufficient. A preferable loading range is 65 to 95%, more preferably 70 to 90%, and particularly preferably 75 to 90%.

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 that maintains a large amount of support and has high 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 ) = SBET × bulk specific gravity (g / cm ³ )
Here, SBET is a surface area (m ² / g) per unit weight of the molded body.
The specific surface area is calculated from the above equation after SBET is measured by the BET method using nitrogen gas as the adsorbed gas after vacuum drying the molded body at room temperature.
As for the method for measuring the bulk specific gravity, when the shape is short, such as a particulate shape, a cylindrical shape, or a hollow cylindrical shape, an apparent volume is measured 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 weight.
The preferred range of the specific surface area ^{is 5m 2 / cm 3 ~500m 2 /} cm 3. If it is 5 m ² / cm ³ or more, the carrying amount and adsorption performance of the adsorption substrate are sufficient. If it is 500 m ² / cm ³ or less, the strength of the molded article is sufficient.

In general, the adsorption performance of an inorganic ion adsorbent that is an adsorption substrate is often proportional to the specific surface area. Therefore, if the specific surface area (surface area per unit volume) is small, the adsorption performance per unit volume is lowered, and it is difficult to achieve high-speed processing and high-capacity processing when the column or tank is packed.
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 the inorganic ion adsorbent, which is an adsorption substrate having a larger specific surface area, is supported on the fibrils at a high content per unit volume, the surface area per unit volume is extremely large.

Next, the manufacturing method of the porous molded object of this invention is demonstrated.
The method for producing the porous molded body of the present invention comprises:
(1) A pulverization / mixing step of obtaining a slurry by pulverizing / mixing at least three kinds of a good solvent of an organic polymer resin, an inorganic ion adsorbent, and a water-soluble polymer using a pulverizing / mixing means,
(2) Dissolution step of dissolving the organic polymer resin in the slurry obtained in step (1),
(3) It is characterized by comprising a molding step in which the slurry obtained in step (2) is molded and solidified in a poor solvent.
By finely grinding the inorganic ion adsorbent in a good solvent of the organic polymer resin, the inorganic ion adsorbent can be made fine particles. Furthermore, in this pulverization / mixing step, the water-soluble polymer acts as a dispersion aid by adding a water-soluble polymer, improving the efficiency of pulverization, and further preventing re-aggregation of the inorganic ion adsorbent. To do. As a result, there are few secondary aggregates in the inorganic ion adsorbent supported on the molded porous molded body.
The mechanism by which the water-soluble polymer works as a dispersion aid will be discussed below.

The water-soluble polymer is adsorbed on the solid surface of the inorganic ion adsorbent, and makes the aggregated solid particles easily wet with a good solvent of the organic polymer resin that is a liquid. By improving the wettability, the aggregate is loosened in a good solvent, and the air in the aggregate can be replaced with a liquid. In addition, since water-soluble polymers with high molecular weight are bulky, an adsorption layer can be formed on the solid surface of the inorganic ion adsorbent to increase the surface charge of the solid particles or to increase the repulsive force between the particles due to steric hindrance. it can.
The water-soluble polymer has two effects, that is, the effect as a dispersant described here and the effect of creating the special porous structure described above. The feature of the present invention is the discovery of a new effect of the water-soluble polymer used in the prior art, and a high effect on the performance and manufacturing aspects of the porous molded body. The performance effect is that there are few secondary agglomerates of the inorganic ion adsorbent in the molded product, so all of the inorganic ion adsorbent used in the preparation is uniformly dispersed throughout the molding, and all of them are effectively involved in the adsorption. However, the contact efficiency with the substance to be adsorbed is extremely high.
Moreover, since there are few secondary aggregates, since it is few that a secondary aggregate breaks from a starting point, durability is also high.
The production effect is that the grinding / dispersion efficiency is high and the grinding time can be shortened. In addition, the stability of the slurry is improved, and the inorganic ion adsorbent is less likely to settle even after long-term storage.

The water-soluble polymer used in the present invention is not particularly limited as long as it is compatible with a good solvent for 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 semisynthetic polymers include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl starch, and methyl starch.

In addition, synthetic polymers include polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, carboxymethyl cellulose, sodium polyacrylate, formalin condensate of naphthalene sulfonate, polystyrene sulfonate, vinyl compounds and carboxylic acid-based monomers. Examples thereof include salts of copolymers with monomers, polyalkylene polyamines, and polyethylene glycols such as tetraethylene glycol and triethylene glycol.
Among these water-soluble polymers, a synthetic polymer is preferable in that it has biodegradation resistance.
In the molded article of the present invention, it is particularly preferable to use polyvinyl pyrrolidone as the water-soluble polymer because it has a high effect of developing a structure having voids inside the fibrils forming the communicating holes.
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. When the weight average molecular weight is 2,000 or more, the effect of developing a structure having voids inside the fibril is enhanced. When the weight average molecular weight is 2,000,000 or less, the viscosity during molding does not increase and molding is easy.

Moreover, well-known dispersing agents, such as surfactant, can also be added in the range which does not affect the structure of a porous molded object.
The pulverizing / mixing means of the present invention is not particularly limited as long as the inorganic ion adsorbent, the good solvent of the organic polymer resin, and the water-soluble polymer can be pulverized and mixed together. For example, physical crushing methods such as pressure fracture, mechanical grinding, ultrasonic treatment, and homogenizer can be used. Typical examples of the pulverizing / mixing means include generator shaft type homogenizers, blenders such as Waring blenders, pulverizers such as sand mills and ball mills, jet mills, mortars and pestles, scourers, and ultrasonic treatment.
A medium agitation type mill such as a ball mill, an attritor or a bead mill is preferred because it has high crushing efficiency and can crush even a high viscosity. A bead mill is more preferable in that the inorganic ion adsorbent can be pulverized and mixed to a nano-sized particle size. The diameter of the ball used for the bead mill is not particularly limited, but a range of 0.1 to 2 mm is preferable. If it is 0.1 mm or more, the ball weight is sufficient, so that the pulverization force is high and the pulverization efficiency is high. If it is 2 mm or less, the ability to finely pulverize is excellent. The material of the ball is not particularly limited, and examples thereof include various ceramics such as iron and stainless steel, alumina and zirconia oxides, and non-oxides such as silicon nitride and silicon carbide.
In particular, zirconia is excellent in that it is excellent in wear resistance and has little contamination to the product (mixture of worn objects).
The operation conditions of the pulverization / mixing means will be described by taking a bead mill as an example, but the present invention is not limited to these.
The initial charging method of the raw material to the pulverizing / mixing means is preferably a circulation method or a premix method. The circulation method is a method in which a solvent is charged into a slurry tank in advance, a circulation pump and a mill are operated only with the solvent, and a material to be crushed is charged little by little. The premix method is a method in which a solvent and a material to be pulverized are mixed and slurried in advance in a separate container. Here, the solvent is a good solvent for the organic polymer resin, and the material to be pulverized refers to an inorganic ion adsorbent. When the dispersion state of the solvent and the material to be crushed is bad and lumps are present, the bead mill screen (bead / slurry separation mechanism) may be clogged.
The peripheral speed of the agitator is preferably more than 3 m / s and less than 20 m / s, and more preferably 8 to 18 m / s. If it exceeds 3 m / s, the problem that the pulverization efficiency is poor and the processing time becomes long can be avoided, and if it is less than 20 m / s, the problem that the beads become unbalanced in the mill and the pulverization efficiency decreases can be avoided.
The treatment temperature is preferably controlled in the range of the freezing point to the flash point of the solvent. Below the freezing point, the pulverization efficiency is extremely lowered, and above the flash point, it is not preferable from the viewpoint of the risk of flammable explosion. Usually, when the pulverization is performed, heat is generated from the frictional heat of the beads, and thus cooling is required. The cooling means is preferably cooled by providing a heat exchanger in the circulation line of the slurry tank and the mill.
The particle size control method for the object to be crushed, that is, the inorganic ion adsorbent, samples the slurry liquid every time the pulverization time elapses, measures the particle size and particle size distribution, and uses the correlation curve between the pulverization time and the particle size distribution. The method is preferred. Moreover, slurry viscosity, slurry temperature, etc. can also be used as a management index instead of grinding time. When the pulverization time is short, the particle size of the material to be pulverized is large, and when the pulverization time is long, the particle size tends to be small and the particle size distribution tends to be narrow.

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. can give.
In particular, ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile (PAN), polysulfone (PS), and polyvinylidene fluoride (PVDF) are preferred because they are non-swellable and biodegradable in water, and easy to manufacture. 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-2pyrrolidone (NMP), dimethylacetamide (DMAC), dimethylformamide (DMF) and the like. These good solvents may be used alone or as a mixed solvent.

Although there is no limitation in particular in the content rate in the good solvent of organic polymer resin, Preferably it is 5 to 40 weight%, More preferably, it is 7 to 30 weight%. A molded body having a sufficient strength is obtained at 5% by weight or more, and a porous molded body having a high porosity is obtained at 40% by weight or less.
The water-soluble polymer content of the molded product of the present invention is expressed by the following formula 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 by
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 0.001% or more, the effect is sufficient to open the surface of the molded body, and if it is 10% or less, the polymer concentration is not relatively reduced and the strength is 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 with 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 to extract the extracted water-soluble polymer. The weight of the high molecular weight is determined.
Further, 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 shift to the poor solvent side during molding, and the content can be increased.

The inorganic ion adsorbent used in the present invention refers to an inorganic substance that exhibits an ion adsorption phenomenon or an ion exchange phenomenon.
For example, natural products include zeolite, montmorillonite, and various mineral substances, and synthetic products include metal oxides and insoluble hydrated oxides. The former is represented by aluminosilicate kaolin mineral with a single layer lattice, bilayer latticed muscovite, sea chlorite, kanuma earth, pyrophyllite, talc, three-dimensional framework feldspar, zeolite and the like. The latter mainly includes composite metal hydroxides, metal oxides, metal hydrated oxides, polyvalent metal salts, insoluble heteropolyacid salts, insoluble hexacyanoferrates, and the like.

Examples of the polyvalent metal salt include hydrotalcite compounds represented by the following formula (II).
M ²⁺ _(1-X) M ³⁺ _x (OH ⁻ ) _{(2 + xy)} (A ⁿ⁻ ) y / n (II)
[ ^Wherein M ²⁺ represents at least one divalent metal ion selected from the group consisting of Mg ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ , Ca ²⁺ and Cu ²⁺ , and M ³⁺ represents Al ³⁺ and Fe ^3+. At least one trivalent metal ion selected from the group consisting of: An ⁿ⁻ represents an n-valent anion, 0.1 ≦ x ≦ 0.5, and 0.1 ≦ y ≦ 0.5 And n is 1 or 2. ]
The metal oxide can be 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 may be an unhydrated (unhydrated) metal oxide in which m in the formula (I) can be represented by 0, or a hydrated (hydrated) metal oxide in which m can be represented by a numerical value other than 0. It may be.
Further, 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 a regularity and is uniformly distributed throughout the oxide, for example, a perovskite structure, spinel It forms a structure, etc., 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.

As the inorganic ion adsorbent, hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated lanthanum oxide, water, because of its excellent adsorption performance of phosphorus, boron, fluorine and arsenic Sum yttrium oxide; a composite metal oxide of a metal element selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum and yttrium and a metal element selected from the group consisting of aluminum, silicon and iron, and activated alumina It is preferably at least one metal oxide selected from the group. Also preferred are aluminum sulfate-added activated alumina, aluminum sulfate-added activated carbon, and the like. The metal oxide represented by the above formula (I) 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 may contain a plurality of metal oxides represented by the formula (I).

There is no particular limitation on the distribution state of each metal oxide in the inorganic ion adsorbent, but in order to effectively utilize the characteristics of each metal oxide and obtain an inorganic ion adsorbent with better cost performance, a specific condition is required. It is preferable to make a mixed structure in which the metal oxide is surrounded by 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 metal oxides include metal oxides in which other elements are dissolved, the structure in which zirconium tetroxide in which zirconium is dissolved is covered with hydrated zirconium oxide in which iron is dissolved. It can be illustrated as a preferred example. In this example, hydrated zirconium oxide has high adsorption performance for ions such as phosphorus, boron, fluorine and arsenic and durability performance 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 of iron tetroxide is covered with hydrated zirconium oxide, the vicinity of the surface of the inorganic ion adsorbent involved in ion adsorption becomes hydrated zirconium oxide with high adsorption performance and durability performance. Since the inside which does not participate in the adsorption becomes inexpensive iron trioxide, it can be used as an adsorbent having high adsorption performance, high durability performance, and low cost, that is, excellent in cost performance.

From the viewpoint of obtaining an adsorbent with excellent cost performance for the adsorption and removal of ions harmful to the environment and health of phosphorus, boron, fluorine and arsenic, the inorganic ion adsorbent is represented by M and N in the formula (I). And at least one of M and N in the formula (I) is titanium, zirconium, tin, cerium, lanthanum, yttrium, and the like around the metal oxide which is a metal element selected from the group consisting of aluminum, silicon and iron It is preferable that the structure is covered with a metal oxide that is a metal element selected from the group consisting of:
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, F / T (molar ratio) where T is the total number of moles of metal elements selected from the group consisting of cerium, lanthanum, and yttrium, and F is the number of moles of metal elements selected from the group consisting of aluminum, silicon, and iron. Is preferably in the range of 0.01 to 0.95, more preferably in the range of 0.1 to 0.90, still more preferably 0.2 to 0.85, It is especially preferable that it is -0.80. This is because if the value of F / T (molar ratio) is excessively increased, the adsorption performance and durability performance tend to be lowered, and if the value is decreased, the effect on the cost reduction is reduced.

Also, depending on the metal, there are a plurality of forms of metal oxides with 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 ₂ O).
In addition, the inorganic ion adsorbent 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. This is because if the BET specific surface area is too small, the adsorption performance is lowered, and if it is too large, the solubility in acid or alkali is increased, and as a result, the durability performance against repeated use is lowered.

Although the manufacturing method of the metal oxide represented by the said formula (I) is not specifically limited, For example, it manufactures with the following methods. A precipitate obtained by adding an alkaline solution to an aqueous salt solution of metal hydrochloride, sulfate, nitrate or the like is filtered, washed and dried. 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.
Next, around at least one of M and N in the formula (I) around the metal 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 A method for producing an inorganic ion adsorbent having a structure covered with a metal oxide, which is a metal element selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium. A case where an inorganic ion adsorbent having a structure in which zirconium oxide is covered is manufactured will be described.
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. Thereafter, an aqueous alkaline solution is added to adjust the pH to 8 to 9.5, preferably 8.5 to 9 to generate a precipitate. Thereafter, the temperature of the aqueous solution is set to 50 ° C., air is blown in while maintaining the pH at 8 to 9.5, preferably 8.5 to 9, and oxidation is performed until ferrous ions cannot be detected in the liquid phase. The resulting precipitate is filtered off, washed with water and dried. 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 salts used in the aforementioned production methods include zirconium oxychloride (ZrOCl ₂ ), zirconium tetrachloride (ZrCl 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 2.0 mol 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 (FeCl ₂ ). Can be mentioned. These may also be hydrated salts such as FeSO ₄ .7H ₂ O. These ferrous salts are usually added as solids, but may be added in the form of a solution.
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 to 20% by weight. When the oxidizing gas is blown, the time varies depending on the kind of the oxidizing gas, but is usually about 1 to 10 hours. As the oxidizing agent, for example, hydrogen peroxide, sodium hypochlorite, potassium hypochlorite and the like are used.

Examples of the poor solvent in 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 0 to 40%, and more preferably 0 to 30%. When the mixing ratio is 40% or less, the coagulation rate does not slow, so the polymer slurry formed into droplets or the like is between the poor solvent and the molded body when entering the poor solvent and while moving in the poor solvent. Good shape without being affected by frictional resistance.
Although the temperature of a poor solvent is not specifically limited, Preferably it is -30 degreeC-90 degreeC, More preferably, it is 0 degreeC-90 degreeC, More preferably, it is 0 degreeC-80 degreeC. When the temperature of the poor solvent is 90 ° C. or lower and −30 ° C. or higher, the state of the molded body in the poor solvent is stabilized.

Next, the non-water treatment application of the porous molded body of the present invention will be described.
The porous molded body of the present invention has a high opening property on the surface of the molded body, the communication holes are developed in a three-dimensional network inside the molded body, and the fibrils forming the communication holes are also porous. The contact efficiency is high.
Applications that make use of the high contact efficiency include adsorbents, deodorants, antibacterial agents, hygroscopic agents, food freshness-retaining agents, enzyme-immobilized carriers, chromatographic carriers, and the like.
For example, when zeolite is used as the inorganic ion adsorbent, a deodorizing effect can be expected.
Furthermore, the inorganic ion adsorbent of the porous molded body of the present invention is zeolite, and when the zeolite carries silver, it exhibits antibacterial properties.
Further, when palladium or platinum is supported, it can be used as a freshness retaining agent because it adsorbs ethylene.
In addition, when silver or copper is supported, a deodorizing effect can be obtained because malodorous gases such as hydrogen sulfide, ammonia, and methyl mercaptan can be adsorbed and decomposed.
In any case, an effect not found in the prior art utilizing the high contact efficiency of the porous molded body of the present invention can be expected.

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.

-Relative cumulative X-ray intensity ratio The distribution state of the inorganic ion adsorbent in the compact was subjected to surface analysis using an electron beam microanalyzer (EPMA) (EPMA 1600, Shimadzu Corporation). The surface analysis data obtained by analysis (specifically, the frequency distribution of X-ray intensity (count number)) was statistically processed.
The frequency distribution of the X-ray intensity of the component elements constituting the inorganic ion adsorbent is integrated from the low X-ray intensity (low concentration) side, and the cumulative X-ray intensity frequency reaches 5%. The value of X-ray intensity was taken as 5% relative cumulative X-ray intensity.
Similarly, the frequency distribution of the X-ray intensity of the component elements constituting the inorganic ion adsorbent is integrated from the low X-ray intensity (low concentration) side, and the total of the X-ray intensity frequencies is 95. The value of the X-ray intensity reaching% was taken as the 95% relative cumulative X-ray intensity.
The relative cumulative X-ray intensity ratio was determined from the following formula.
Relative cumulative X-ray intensity ratio = 95% relative cumulative X-ray intensity / 5% relative cumulative X-ray intensity

-Preparation of sample for electron beam microanalyzer (EPMA) The molded body was vacuum-dried at room temperature. After cutting the dried molded body with a razor, osmium (Os) was deposited. Then, after embedding with an epoxy resin and creating a cross section by polishing, an osmium (Os) was again deposited to prepare a sample for EPMA in which the inside of the molded body was observed.

-Amount of inorganic ion adsorbent supported The molded body was vacuum dried at room temperature for 24 hours. 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 fired at 800 ° C. for 2 hours using an electric furnace, and the weight of ash was measured to obtain the weight Wa (g) of ash. The supported amount was determined from the following formula.
Load (%) = Wa / Wd × 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 After the molded body was vacuum-dried at room temperature, the surface area per unit weight of the porous molded body by BET method using Beckman Coulter Co., Ltd. Coulter SA3100 (trade name) and nitrogen as the adsorbed gas. SBET (m ² / g) was determined.
Next, the apparent volume V (cm ³ ) of the wet compact was measured using a graduated cylinder or the like. Then, it vacuum-dried at room temperature and calculated | required weight W (g).
The specific surface area referred to in the molded product of the present invention was determined from the following formula.
Specific surface area (m ² / cm ³ ) = SBET × bulk specific gravity (g / cm ³ )
Bulk specific gravity (g / cm ³ ) = W / V
In the formula, SBET 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 its apparent volume (cm ³ ).

-Particle size of compact and inorganic ion adsorbent Particle size of compact and inorganic ion adsorbent was measured with a laser diffraction / scattering particle size distribution analyzer (LA-950 (trade name) manufactured by HORIBA). did. However, when the particle diameter was 2,000 μm or more, 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 diameter.

-Porosity The molded product that had been sufficiently wetted with water was spread on dry filter paper, and after removing excess moisture, 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 used as the weight (W0) when the molded body was dried.
Next, a specific gravity bottle (Geryusac type, capacity 10 ml) was prepared, and when the specific gravity bottle was filled with pure water (25 ° C.), the weight was measured to obtain the full weight (Ww). Next, the molded body wet in pure water was put into this specific gravity bottle, and the pure water was filled up to the marked line and the weight was measured to obtain (Wwm). Next, this 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 compact were determined according to the following 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 contains water, W0 is the weight (g) after drying the molded body, and ρ is the specific gravity (g / Cm ³ ), M is the weight (g) after drying of the molded body, Ww is the weight when the specific gravity bottle is full (g), and Wwm is the weight when the molded body and pure water contained in the specific gravity bottle are added ( g).

-Observation of a molded object with a scanning electron microscope Observation of the molded object with a scanning electron microscope (SEM) was performed with an S-800 scanning electron microscope manufactured by Hitachi, Ltd.

-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 in a gelatin capsule having a diameter of 5 mm together with IPA 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.

-Opening diameter of the surface Obtained by actual measurement from the image of the surface of the molded body taken using 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.

-Surface aperture ratio The image of the surface of the molded body photographed using a scanning electron microscope was determined using image analysis software (Win Roof (trade name) manufactured by Mitani Corporation).
More specifically, the obtained SEM image is recognized as a grayscale image, and the threshold value is manually adjusted by dividing the dark portion into an opening portion and the light portion as a fibril portion, and dividing into an opening portion and a fibril portion. The area ratio was obtained.

・ Phosphorus adsorption amount Trisodium phosphate (Na ₃ PO ₄ · 12H ₂ O) is dissolved in distilled water to make a solution with a phosphorus concentration of 9 mg-P / L (P is phosphorus, L is liter), and the pH is adjusted with sulfuric acid. The liquid adjusted to 7 was used as a model liquid, that is, an adsorption stock solution.
8 ml of the porous molded body 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). The effluent (treatment solution) from the column is sampled every 30 minutes, the phosphate ion concentration (phosphorus concentration) in the treated water is measured, and the flow until 0.5 mg-P / L (ppm) is exceeded. The amount of water (adsorption amount mg-P / LR (R is a porous molded body)) was determined. The phosphate ion concentration was measured using a phosphoric acid measuring device Phosfax Compact (trade name) manufactured by HACH.

[Example 1]
375 g of polyvinylpyrrolidone (PVP, BASF Japan K.K., Luvitec K30 Powder (trade name)) was dissolved in 4125 g of dimethyl sulfoxide (DMSO, Kanto Chemical Co., Inc.) to obtain a uniform solution. Using a bead mill (SC100, Mitsui Mining Co., Ltd.) filled with 2250 g of cerium oxide powder (Iwatani Sangyo Co., Ltd.) having an average particle size of 30 μm to 4500 g of the solution and filled with zirconia balls having a diameter of 1 mmφ for 30 minutes Grinding and mixing were performed to obtain a yellow slurry. Further, 375 g of an ethylene vinyl alcohol copolymer (EVOH, Nippon Synthetic Chemical Industry Co., Ltd., Soarnol E3803 (trade name)) was heated to 60 ° C. in a dissolving tank, and a stirring blade was used. The mixture was stirred and dissolved to obtain a uniform slurry solution.
The obtained polymer slurry is heated to 40 ° C., supplied to the inside of a cylindrical rotating container with a nozzle having a diameter of 5 mm on the side, and this container is rotated to form droplets from the nozzle by centrifugal force (15 G). And it was made to discharge in the coagulation bath which consists of 60 degreeC water, and the polymer slurry was coagulated. Furthermore, washing | cleaning and classification were performed and the spherical molded object with an average particle diameter of 600 micrometers was obtained.
The physical properties are shown in Table 1.

The result of having observed the surface and fractured surface of the obtained molded object using the scanning electron microscope (SEM) was shown to FIGS.
Observation of the entire fractured surface from FIGS. 1 and 2 confirmed that the inorganic ion adsorbent was uniformly dispersed and supported.
Furthermore, surface analysis inside the compact was performed for cerium (Ce), which is a constituent element of the inorganic ion adsorbent, using an electron beam microanalyzer (EPMA). As a result of the analysis, the relative cumulative X-ray intensity ratio was 1.9.
Further, from FIG. 1, it was observed that the obtained molded body had a maximum pore diameter layer (void layer) in the vicinity of the surface.
From FIG. 3, it was confirmed that the molded body had no skin layer formed on the outer surface and was open.
From FIG. 4, it was confirmed that voids inside the fibrils and pores on the surface of the fibrils were formed, and that the inorganic ion adsorbent powder was supported on the outer surface of the fibrils and the surface of the voids inside the fibrils. .
The amount of phosphorus adsorbed on this porous molded body was 5.7 g-P / LR.
Moreover, the content rate of the water-soluble polymer (polyvinylpyrrolidone) of this molded object was 0.1 weight%.

(Test Example 1)
The polymer slurry obtained by the same method as in Example 1 was allowed to stand for 8 hours, and the state of precipitation was observed. No sediment was observed at the bottom of the container, and it was confirmed that the polymer slurry of Example 1 was stable.
[Example 2]
A spherical molded body having an average particle diameter of 600 μm was obtained in the same manner as in Example 1 except that the pulverization / mixing time was 5 minutes.
The physical properties are shown in Table 1.
[Example 3]
A spherical molded body having an average particle diameter of 600 μm was obtained in the same manner as in Example 1 except that zirconia balls having a diameter of 0.5 mmφ were used for pulverization and mixing.
The physical properties are shown in Table 1.

(Comparative Example 1)
Instead of grinding and mixing with a bead mill, instead of using a stirring blade in a cylindrical container having a capacity of 10 L, mixing was performed at 300 rpm for 8 hours to obtain a yellow slurry. A porous molded body was obtained in the same manner. The average particle size was 600 μm.
The physical properties are shown in Table 1.
The result of having observed the surface and the fractured surface of the obtained molded object using the scanning electron microscope (SEM) was shown to FIGS.
When the entire fractured surface was observed from FIGS. 5 and 6, it was confirmed that some inorganic ion adsorbents were supported by forming secondary aggregates.
Furthermore, surface analysis inside the compact was performed for cerium (Ce), which is a constituent element of the inorganic ion adsorbent, using an electron beam microanalyzer (EPMA). As a result of analysis, the relative cumulative X-ray intensity ratio was 10.5.
From FIG. 7, it was confirmed that the molded body had no skin layer formed on the outer surface and was open. Further, from FIG. 8, it was confirmed that voids inside the fibrils and pores on the fibril surface were observed, and that the inorganic ion adsorbent powder was supported on the outer surface of the fibrils and the surface of the voids inside the fibrils. .
The amount of phosphorus adsorbed by this porous molded body was 4.6 g-P / LR, which was smaller than in the examples. This is presumably because part of the supported inorganic ion adsorbent is supported as secondary aggregates, so that the contact efficiency with phosphate ions is poor, and as a result, the phosphorus adsorption amount is low.

(Test Example 2)
The polymer slurry obtained by the same method as in Comparative Example 1 was allowed to stand for 8 hours, and the state of precipitation was observed. A sediment was observed at the bottom of the container. It was confirmed that the polymer slurry of Comparative Example 1 was inferior in stability.

  Since the molded article of the present invention has no skin layer and is excellent in surface openability, diffusion of the target substance into the molded article is fast. Moreover, since the supported inorganic ion adsorbent has few secondary aggregates, the contact efficiency with the target substance is extremely high. Therefore, it is suitable for adsorbents and filter agents, deodorizers, antibacterial agents, hygroscopic agents, food freshness-preserving agents, various chromatographic carriers, catalysts and the like used for liquid and gas treatment.

Claims (21)

  A porous molded body comprising an organic polymer resin and an inorganic ion adsorbent, which is obtained by using an electron beam microanalyzer (EPMA) and is supported on the porous molded body The said porous molded object including the ratio (relative cumulative X-ray intensity ratio) of 95% relative cumulative X-ray intensity and 5% relative cumulative X-ray intensity of the component elements constituting 1 to 10.   The porous molded body has voids inside the fibrils forming the communication holes, and at least a part of the voids are open at the surface of the fibrils, and the outer surface of the fibrils and the void surface inside the fibrils The porous molded body according to claim 1, wherein an inorganic ion adsorbent is supported on the porous molded body.   The porous molded body according to claim 1, wherein the communication hole has a maximum pore diameter layer near the surface of the molded body.   The porous molded object as described in any one of Claims 1-3 whose average particle diameter is 100-2500 micrometers.   The organic polymer resin comprises at least one selected from the group consisting of ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile (PAN), polysulfone (PS), and polyvinylidene fluoride (PVDF). The porous molded object as described in any one of 1-4. The porous molded body according to any one of claims 1 to 5, wherein the inorganic ion adsorbent contains 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 porous molded body according to claim 6, wherein the metal oxide is one or a mixture of two or more selected from the group consisting of any of the following (a) to (c).
(A) hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated lanthanum oxide, and hydrated yttrium oxide (b) composed of titanium, zirconium, tin, cerium, lanthanum, and yttrium Composite metal oxide (c) activated alumina of a metal element selected from the group and a metal element selected from the group consisting of aluminum, silicon, and iron   The porous molded body according to any one of claims 1 to 5, wherein the inorganic ion adsorbent comprises at least one selected from the group consisting of aluminum sulfate-added activated alumina and aluminum sulfate-added activated carbon.   The porous molded body according to any one of claims 1 to 8, wherein the supported amount of the inorganic ion adsorbent is 65 to 95%.   The porous molded body according to any one of claims 2 to 9, wherein the fibril comprises an organic polymer resin, an inorganic ion adsorbent, and a water-soluble polymer.   The porous molded body according to claim 10, wherein the water-soluble polymer is a synthetic polymer.   The porous molded body according to claim 10 or 11, wherein the water-soluble polymer is polyvinylpyrrolidone.   The porous molded object as described in any one of Claims 10-12 whose content of the said water-soluble polymer is 0.001 to 10%.   A column packed with the porous molded body according to any one of claims 1 to 13.   A method for producing a porous molded article comprising an organic polymer resin and an inorganic ion adsorbent, (1) pulverizing at least three types of a good solvent for the organic polymer resin, an inorganic ion adsorbent, and a water-soluble polymer・ Crushing / mixing step to obtain slurry by pulverizing / mixing using mixing means, (2) dissolving step of dissolving organic polymer resin in slurry obtained in step (1), (3) obtained in step (2) A method for producing a porous molded body, comprising a molding step in which a slurry is molded and solidified in a poor solvent.   The method according to claim 15, wherein the pulverizing and mixing means is a medium stirring mill.   The good solvent of the organic polymer resin is at least one selected from the group consisting of dimethyl sulfoxide (DMSO), N-methyl-2pyrrolidone (NMP), dimethylacetamide (DMAC), and dimethylformamide (DMF). Item 15. The method according to Item 15 or 16.   The method according to any one of claims 15 to 17, wherein the poor solvent is water or a mixture of a good solvent for organic polymer resin and water.   The method according to any one of claims 15 to 18, wherein a mixing ratio of a good solvent of the organic polymer resin and a mixture of water is 0 to 40%.   The molding method is to spray droplets from a nozzle provided on the side of a rotating container by dispersing slurry containing an organic polymer resin, a good solvent for the organic polymer resin, a water-soluble polymer, and an inorganic ion adsorbent. 20. A method according to any one of claims 15 to 19, comprising forming.   A porous adsorbent comprising the porous molded body according to any one of claims 1 to 13.