JP4907585B2 - Water treatment apparatus and water treatment method - Google Patents

Abstract

Water processing device and method are provided. When switching an absorption tower for communicating liquid, adjusting pH value of recycled processed water to maintain the pH in a standard of discharge, directly discharging. The device comprises three above absorption elements that fill an adsorbent absorbs materials contained in the processed water and set circularly in sequence; an element that connects any two towers in series in a sequence; an element that provides the processed liquid to a preceding stage of the two towers; a recycling element that recycles processed liquid that is absorbed and processed by the processed liquid of a backward stage; a switching element that takes the backward stage as the preceding stage in two new towers and the absorption element adjacent to the backward stage as the backward stage of the new two towers and switching repeatedly the two towers to the new two towers along penetration of the preceding stage; a back conveying component that recycles the processed liquid to the preceding stage of the two new towers before the processed liquid is supplied to the preceding stage of the two new towers and the processing liquid is supplied to the backward stage of the two new towers after penetration.

Description

The present invention relates to a water treatment apparatus for treating various types of wastewater such as sewage, various factories such as industrial wastewater from food factories and chemical factories, and domestic wastewater from households, and a water treatment method using the same.
More specifically, the present invention relates to a water treatment apparatus or a water treatment method that can selectively adsorb and remove phosphorus, boron, arsenic, and fluorine ions in water.

In recent years, in order to cope with environmental pollution and eutrophication, 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, and technology to remove them The demand for is increasing.
For example, phosphorus is one of the causative substances of eutrophication, and regulations are increasing in closed water areas. Specifically, the discharge standard for phosphorus in closed water areas is regulated to 0.5-2 mg / liter or less. Has been.
In addition, boron is an essential element for plant growth, but it is known that if it is present in excess, it will adversely affect the growth of the plant. It has been pointed out that it may cause health problems, particularly health problems such as reduced reproductive function.

Arsenic is also contained in wastewater from nonferrous metal refining industry, thermal wastewater from geothermal power plants, and groundwater in specific areas. Arsenic accumulates in the living body and is said to cause chronic poisoning, weight loss, sensory injury, liver damage, skin deposition, skin cancer and the like. Arsenic is regulated to 0.1 mg / liter or less by the drainage standard.
A large amount of fluorine is contained in wastewater from metal refining, glass, electronic material industries, and the like. Fluorine is known to cause adverse effects on the human body such as chronic fluorine poisoning such as patchy teeth, osteosclerosis, and thyroid disorders when taken in excess. The water quality standard for fluorine is 0.8 mg / liter or less for tap water.

As a technique for removing various harmful ions as described above, Patent Document 1 below proposes an ion removal / recovery system that allows water to pass through a so-called merry-go-round system.
In this, an adsorbent composed of an inorganic ion adsorbent and an organic polymer was packed into three fixed bed adsorption towers (hereinafter referred to as A tower, B tower, and C tower in the order of liquid flow). A system having a configuration.
First, the tower A and the tower B are connected in series, and the removal treatment is performed by passing the liquid from the tower A to the tower B. When tower A breaks through and the utilization rate of the adsorbent in tower A is sufficiently high, the use of tower A is stopped, and then the tower B and tower C are connected in series. The removal treatment is performed by passing the solution through the C tower, and the activation treatment of the A tower is performed during that time.
Next, when the tower B breaks through, the tower C and the activated tower A are connected in series to perform the removal process, and the tower B is activated in the meantime.
In this way, two towers are communicated in series two by two, and are cyclically used in a predetermined order of use, so that the adsorbent utilization rate can be maintained continuously while maintaining a high utilization rate of the adsorbent. The hazardous substance removal process is performed so that no harmful substance leaks.

In FIG. 11, the typical block diagram of an example of the conventional system mentioned above is shown.
In the water treatment apparatus shown in FIG. 11, first, when the tower A and the tower B are used as a configuration in series, the liquid to be treated (raw water 1 in the figure) is detector D1 → valve V1 → adsorption tower A. It passes through the order of valve V8 → detector D3 → adsorption tower B → valve V5 → line 20 → detector D8, and finally becomes a treated liquid (treated water 2 in the figure) in a treated state.
Hereinafter, in the case of using the B tower and the C tower, also in the case of using the C tower and the A tower, the same liquid flow is performed by switching the line, and finally the treated liquid (treated water 2 in the figure) is used. ) Is obtained.

JP 2006-346545 A

However, when various harmful ions are removed as described above, there are the following problems.
When switching from the two towers used in the previous process (for example, the above tower A and B tower) to the newly used two towers (for example, the above tower B and C), the adsorbent is activated. In this case, the acid or alkali used in an excessive amount is present in the later stage tower (in this case, C tower) newly added to the treatment, so that the liquid to be treated is directly put into the tower (B tower and C tower). ), The pH of the treated liquid (treated water 2) changes abruptly from the previous step, causing a problem that the environmental standard is not satisfied.
In order to cope with this problem, conventionally, an operation of further neutralizing the treated liquid has been required.
In particular, when the amount of treatment such as secondary treatment of sewage is large, applying the above-described system, in order to neutralize the pH of the treated liquid to the pH 5.8 to 8.6 of the discharge standard, it is enormous. Since an amount of neutralizing agent (acid or alkali) is required, it has been a problem in terms of cost and environment.

  Therefore, in the present invention, in view of the above-mentioned problems of the prior art, when switching the adsorption means to be used in a so-called merry-go-round water treatment apparatus, the pH of the collected treated water (treated water) is within the discharge standard. A water treatment apparatus having a configuration that is adjusted so as to be within the range, and a water treatment method using the same.

As a first invention, a water treatment apparatus having the following configuration is proposed in order to solve the above-described problems of the prior art.
The adsorbent capable of adsorbing the substance contained in the liquid to be treated is filled, and among the adsorbing means, the use order is continuous among three or more adsorbing means whose circulation order is determined in advance. Arbitrary two units are connected in series according to the order of use, and a forward feed means for transferring the liquid to be treated in a direction according to the order of use, and the liquid to be treated are disposed in the preceding stage of the two adsorption means. A means for supplying, a means for recovering the treated liquid in which the substance contained in the liquid to be treated has been adsorbed via the latter stage of the two adsorption means, following the former stage, and the former stage With the breakthrough, the rear stage is set as a front stage of two new units in which the use order is continued, and the suction means following the rear stage following the use order is set as the rear stage of the new two units, the suction means according to the order of use. Switching to switch repeatedly And a stage before supplying the liquid to be processed to the two previous stages switched by the switching means, the liquid to be processed is supplied to the subsequent stage of the two new groups, And a reverse feed means for transporting and recovering to the previous stage.
When the liquid to be treated is transferred to the front stage of the two new groups by the reverse feeding means, the acid or alkali for activating the adsorbent that is excessive in the new rear stage becomes the adsorbent in the new two previous stages. Reactivate

  The water treatment apparatus can detect the water quality of the liquid to be treated both when the liquid to be treated is transferred by the progressive means and when the liquid to be treated is transferred by the reverse means. It is preferable that a water quality detection means is provided.

  It is preferable that the adsorbent contains at least an inorganic ion adsorbent.

The inorganic ion adsorbent preferably contains at least one metal oxide represented by the following formula (1).
MNxOn · mH ₂ O (1)
However, in Formula (1), x is 0-3, n is 1-4, m is 0-6. 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 consisting of different ones.

It is preferable that the metal oxide is one or a mixture of two or more selected from any of 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) 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.
(C) Activated alumina.

  The adsorbent contains at least an organic polymer resin and the inorganic ion adsorbent, and is a porous molded body having communication holes that are open to the outer surface, and has voids inside the fibrils that form the communication holes. In addition, it is preferable that at least a part of the void is open at the surface of the fibril, and the inorganic ion adsorbent is supported on the outer surface and the inner void surface of the fibril.

Moreover, the water treatment method using the said water treatment apparatus is proposed as 2nd invention.
That is, first, the liquid to be treated is supplied to the preceding stage of the two adsorption means by the progressive means, and the substance has been adsorbed from the liquid to be treated via the latter two stages. A step of collecting the liquid is performed. With the breakthrough of the previous stage, the subsequent stage is set as two new previous stages in which the use order continues, and the adsorbing means following the subsequent stage in accordance with the use order is set as the new two subsequent stages. The process of switching repeatedly according to is performed. Subsequently, as a pre-stage for supplying the liquid to be processed to the previous stage of the two new units by the reverse feeding means, the liquid to be processed is supplied to the subsequent stage of the two new groups, and then the new two A reverse feed process is carried out in which it is transferred to the previous stage of the base and recovered.
Since the liquid to be treated is transferred to the front stage of the two new groups by the reverse feeding process, the adsorbent-activating acid or alkali that is excessively present in the new rear stage is contained in the new two front stages. The function of reactivating the adsorbent is exhibited, and there is no need to separately adjust the pH of the treated liquid.

In addition, it is desirable that the reverse feeding process is completed in a state where the water quality of the liquid to be treated collected from the two previous stages satisfies the discharge standard.
Thereby, the function of the adsorption | suction means which became new 2 units | sets in the subsequent forwarding process performed succeedingly can be utilized.

According to the present invention, harmful substances and the like contained in the liquid to be treated can be reliably removed until a good state is obtained, and a separate neutralization step is not required for the collected treated liquid, The amount of the neutralizing agent that has been required in the past can be greatly reduced by adjusting within the discharge standard.
Furthermore, in the reverse feeding process, the activated chemical eluted from the adsorption tower which was a new latter stage reactivated the previous stage adsorbent, and was able to increase the adsorption capacity.

  The best mode for carrying out the present invention (hereinafter, an embodiment of the present invention) will be described in detail below. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

FIG. 1 shows a schematic configuration diagram of an example of a water treatment apparatus used in the present embodiment.
The water treatment apparatus of FIG. 1 has a configuration in which three adsorption towers (A tower, B tower, C tower) are arranged as adsorption means.
In addition, if the number of adsorption towers is three or more, it can be used continuously by switching cyclically, but the three tower configuration is preferable from the viewpoint of the function of the so-called merry-go-round method and the simplification of the equipment configuration.
Even when the number of towers is four or more, if the order of use is maintained and two or more towers are used in series, and at least one tower is in a dormant state at the same time, the adsorbent per tower is further reduced. The utilization rate can be increased.
In the following, a water treatment apparatus having a configuration in which three adsorption towers are arranged according to FIG. 1 will be described as an example.

The adsorption towers A to C are filled with an adsorbent having a function of adsorbing harmful substances and unnecessary substances contained in the liquid to be treated (raw water 1).
The adsorbent may be a material having a function of adsorbing the substance, but in order to remove harmful ions, it needs to be a predetermined ion exchanger.
In order to activate the ion exchanger, treatment with acid or alkali is required. For this reason, on the line of the water treatment apparatus, as a water quality detection means (hereinafter, also simply referred to as a detector), a pH detector or harmful ions that are to be removed from the liquid to be treated (raw water 1). It is preferable to arrange a densitometer for measuring the concentration.

Hereinafter, description will be made assuming that the adsorbent has a function as an ion exchanger.
The order of use of the three adsorption towers is determined in the order of A tower → B tower → C tower → A tower (hereinafter, repeated).
The treatment of the raw water 1 uses any two towers in the order of use and follows the order of use described above.
Specifically, the tower A and the tower B are used in series communication → the tower B and the tower C are used in series communication → the tower C and the tower A are used in series communication → the tower A Processing is performed by cyclically switching one tower at a time, such as using the tower B in series.

In this water treatment apparatus, there is provided a sequential feeding means having a function of connecting any two units in the order of use in series according to the order of use and transferring the liquid to be treated according to the order of use. .
The progressive means will be specifically described.
From the outlet line 21 of the adsorption tower A to the inlet line 12 of the adsorption tower B via the valve V8 and the detector D3, the line 41 for the forward feed, from the outlet line 22 of the adsorption tower B to the valve V10 and the detector D5 Then, a progressive line 42 leading to the inlet line 13 of the adsorption tower C, and a progressive line leading from the outlet line 23 of the adsorption tower C to the inlet line 11 of the adsorption tower A via the valve V12 and the detector D7. The line 43 constitutes the progressive means.
By adopting such a line configuration, the so-called merry-go-round method functions effectively.

In the water treatment apparatus in the present embodiment, the liquid to be treated (raw water 1) is supplied to the front stage of the two adsorption towers communicating in series by a predetermined supply means.
As supply means for supplying the raw water 1 to the previous stage, a line 10 that introduces the raw water 1 from outside the system into the water treatment device and reaches the valves V1, V2, V3 of the inlet pipes of the respective adsorption towers via the detector D1. Is provided.
The valves V1, V2, and V3 can be supplied to a target tower among the adsorption towers A to C by appropriately switching the opening and closing of the valves V1, V2, and V3.
Further, among the adsorption towers, the ones in the order in the case of sequential feeding in accordance with the determined order of use are referred to as “front stage”, and the ones after the order are referred to as “back stage”.

In the water treatment apparatus according to the present embodiment, it is assumed that a means for collecting the treated liquid after passing through the subsequent stage is provided following the preceding stage.
As a means for recovering this treated liquid (treated water 2), detectors before the discharge outlet from the lines 21, 22, and 23, which are outlet pipes at the bottom of each adsorption tower, respectively, via valves V4, V5, and V6, respectively. A line 20 leading to D8 is provided.
If it is determined by the detector D8 that the discharge standard (water quality environmental standard) is satisfied, the treated water 2 is discharged out of the system.

In the water treatment apparatus according to the present embodiment, with the breakthrough of the previous stage, the rear stage is set to two new front stages in which the order of use continues, and the adsorbing means that follows the rear stage according to the order of use is the new 2 A switching means for switching the two groups to new two groups in accordance with the order of use is provided so as to be the latter stage of the group.
As this switching means, valves V1 to V6, V8, V10, V12 and detectors D3, D5, D7 are provided, respectively.
At that time, the adsorption tower at the rear stage of the two units used before switching is made the former stage of the new two units, and the adsorption tower following the latter stage that has been used up to now according to the order of use is replaced with two new adsorption towers. Each valve is opened and closed so as to be the latter stage. By such an operation, it switches to two new units.

FIG. 2 shows an apparatus configuration diagram in which the tower A and the tower B are connected in series, and harmful substances and the like are removed from the raw water 1 by adsorption.
Valves V1, V8, and V5 are open, and the other valves are closed. The raw water 1 flows in the direction of the arrow along the solid line in the figure. Specifically, water is passed through the detector D1, the valve V1, the adsorption tower A, the valve V8, the detector D3, the adsorption tower B, the valve V5, and the detector D8 in this order.
In addition, the broken line in FIG. 2 is a state in which no liquid flows, which means that the adsorption tower C has undergone an activation process or is at rest. The same applies to the following.

When the water treatment apparatus is configured as shown in FIG. 2 and the raw water 1 is passed through and the adsorption treatment is performed for a while, the adsorption function of the adsorption tower A decreases, and the harmful ions that are the objects of adsorption are detected by the detector D3. Will come to be.
However, at the initial stage where harmful ions are detected, the adsorbent that has not adsorbed harmful ions still remains in the adsorption tower A, so that the concentration of harmful ions is kept at a predetermined reference value. Use of the adsorption tower A is continued until it reaches. Then, when the reference value is reached, it is determined that the adsorption tower A is in a breakthrough state, and use is stopped.

After the previous stage breaks through as described above, the switching means is reconfigured so that two new processing towers communicate in series.
In the water treatment apparatus according to the present embodiment, the raw water 1 (liquid to be treated) is used as a pre-stage for supplying the raw water 1 (liquid to be treated) to the treatment tower that is a new previous stage. And a reverse feeding means having a function of transferring to a new upstream processing tower and collecting it.
This reverse feed means that when switching to two new adsorption towers and starting normal adsorption treatment, the pH of the treated water changes rapidly and does not exceed the water quality discharge standard for discharge. It has a function.
Here, “reverse feeding” means that the liquid is fed in a predetermined order of use, that is, in the direction opposite to the liquid passing direction of the liquid to be treated.
As the reverse feeding means in the example of FIG. 1, a line 51 that branches from the outlet line 21 of the adsorption tower A to the valve V7 and reaches the inlet line 13 of the adsorption tower C via the detector D2, the adsorption tower B Branching from the outlet line 22 of the adsorption tower A through the valve V9, branching through the detector D4 to the inlet line 11 of the adsorption tower A, and from the outlet line 23 of the adsorption tower C through the valve V11. The line 53 that reaches the inlet line 12 of the adsorption tower B via the detector D6 corresponds to this.

After the removal treatment is performed in a configuration in which the adsorption tower A and the adsorption tower B are communicated in series, the switching means is replaced with two new treatment towers, the treatment tower B becomes a new front stage, and the treatment tower C It becomes a new latter stage.
A process of performing reverse feeding of the liquid to be treated will be described with reference to FIG.
In the water treatment apparatus having the configuration shown in FIG. 3, the valves V3, V11, and V5 are open, the other valves are closed, and the liquid to be treated (raw water 1) flows in the direction of the arrow in the figure.
Specifically, it flows in the order of detector D1, valve V3, adsorption tower C, valve V11, detector D6, adsorption tower B, valve V5, and detector D8. In this case, the adsorption tower C is a newly used adsorption tower (new rear stage).
If this adsorption tower C is used as it is, the acid or alkali used excessively for the activation treatment of the adsorbent in the adsorption tower C will flow out, and the pH of the effluent will exceed the water quality discharge standard for discharge.
However, in the water treatment apparatus in the present embodiment, the liquid is passed through the adsorption tower B via the line 53.
By performing reverse feeding in this way, the acid or alkali that has flowed out of the adsorption tower C activates the adsorbent in the adsorption tower B.
In this reverse feed step, it is necessary to confirm that the liquid to be treated discharged from the outlet line 22 of the adsorption tower B satisfies the discharged water quality standard. As a result, the adsorbent of the adsorption tower B is effectively used, and the water quality discharge standard of the reversely processed liquid to be recovered is also satisfied.

At the stage where it was confirmed that the pH of the liquid to be treated recovered in the above-mentioned reverse feed process became almost uniform, it was determined that excessive acid or alkali in the new upstream adsorption tower was consumed. The
Thereafter, as shown in FIG. 4, the respective valves are switched so that the adsorption tower B (front stage) and the adsorption tower C (back stage) communicate with each other in series, and the liquid to be treated (raw water 1) is ordered in this order. The second stage of the normal adsorption removal process is performed.
That is, in FIG. 4, the valves V2, V10, V6 are opened and the other valves are closed, and the liquid flow is performed according to the arrows in the figure. Thereby, harmful ions in the raw water are removed by adsorption. In addition, while the adsorption tower B and the adsorption tower C are operating, the adsorption tower A is in a state of being stopped after receiving the activation process, and is prepared for later use.

As described above, if the adsorption removal process with the combination of the adsorption tower B and the adsorption tower C is continuously performed, the adsorption tower B (previous stage) breaks through and the detector D5 has harmful ions having a predetermined reference concentration or more. Will be detected.
At this stage, the use of the adsorption tower B is stopped, and the adsorption tower switching and the reverse feeding process are performed again in the same manner as described above. The structure of the water treatment apparatus in this case and the liquid flow in the reverse feeding process are shown in FIG.
In FIG. 5, the adsorption tower C (front stage) and the adsorption tower A (rear stage) communicate with each other in series, and in the reverse feed process, the valves V1, V7, V6 are opened and the other valves are closed. Thus, the liquid to be treated (raw water 1) flows according to the arrows in the figure.
Here, the adsorption tower A is activated in the above-described resting state, so that the treatment liquid flowing out from the adsorption tower A contains an acid or alkali that is excessively used for activation. It has become. Therefore, by transferring from the adsorption tower A to the adsorption tower C by the reverse feeding step, the adsorbent of the adsorption tower C is activated, and the pH is controlled within the discharged water quality standard.

When the pH of the treated liquid (treated water 2) is stabilized by continuously performing the above-described reverse feeding process, the adsorption tower C and the adsorption tower A are set in a forward direction with respect to a predetermined order of use. The valve is opened and closed, and the third stage adsorption removal step is performed in the same manner as in FIGS.
The state of the liquid flow in this case is shown by the arrow in FIG. In FIG. 6, the valves V3, V12, and V4 are opened, and the other valves are closed to perform the adsorption removal process. While the adsorption tower A and the adsorption tower C are operating, the adsorption tower B becomes inactive and undergoes an activation process.

As described above, if the adsorption removal process using the adsorption tower C and the adsorption tower A is continuously performed, the adsorption tower C eventually breaks through, and the detector D7 detects harmful ions having a predetermined reference concentration or more. Become. At this stage, the use of the adsorption tower C is stopped, and the adsorption tower switching and the reverse feeding process are performed again in the same manner as described above. The state of the liquid flow in this case is shown by the arrow in FIG. In FIG. 7, the valves V2, V9, and V4 are opened, the other valves are closed, and the reverse feed process is performed until the pH of the treated water discharged from the adsorption tower B is stabilized.
When the pH of the treated liquid (treated water 2) is stabilized, the liquid flow is switched in the forward direction, and the adsorption tower A and the adsorption tower B are connected in series in the forward direction as shown in FIG. As shown in FIG.
Similarly, in the apparatus configuration shown in FIGS. 2 to 7, the removal of harmful substances from the liquid to be treated is repeated.

  As described above, the treated liquid (treated water 2) deviates from the predetermined discharge standard by repeatedly performing the adsorption removal process by the progressive feeding process, the switching of the adsorption tower to be applied, and the pH adjustment by the reverse feeding process. Therefore, it is possible to continuously remove harmful ions over a long period of time.

Next, the detectors D1 to D7 having a function of performing a predetermined measurement on the treated liquid discharged from the adsorption towers A to C constituting the water treatment apparatus described above are functions capable of measuring the water quality at the corresponding location. If it has, it will not specifically limit.
Examples thereof include a pH meter, a redox potential meter, a conductivity meter, a turbidity meter, a dissolved oxygen meter, and various ion measuring means.
The ion measuring means can be appropriately selected depending on the type of ions to be processed. Specific examples include a phosphate ion concentration meter, a fluorine ion concentration meter, and a borate ion concentration meter. When phosphate ions are to be treated, a total phosphorus concentration meter can also be used. In particular, it is preferable to include a pH meter in the water quality detection means in that the pH of the treated water can be directly managed. These measurement states are not limited to being monitored online, and the treated water sampled offline may be appropriately inspected and managed using, for example, an ICP emission analysis method or a colorimetric method.
The timing of switching the adsorption tower may be determined by detecting the capacity of treated water in the adsorption tower by a detector, but may be determined by measuring the water passage time. Good.

Moreover, in the water treatment apparatus mentioned above, although the case where the number of adsorption towers used in series was 2 was demonstrated, the number of adsorption towers can be changed suitably.
As the number of adsorption towers increases, the treatment capacity for harmful ions increases, but on the other hand, the initial cost as a water treatment device increases.
Therefore, the minimum number of adsorption towers operated in a state of being connected in series is 2, and the maximum number is one less than the total number of adsorption towers provided in the water treatment apparatus.

Next, the adsorbent filled in the adsorption tower will be described.
The adsorbent has a function of adsorbing a substance contained in the liquid to be treated, and is not particularly limited.
For example, an inorganic ion adsorbent is suitable as a material having a function of adsorbing harmful ions contained in wastewater generated from sewage, food factories, chemical factories, homes, and the like.
In addition, an inorganic ion adsorbent 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. Natural products include kaolin minerals with aluminosilicate and single layer lattice, bilayer lattice muscovite, sea green stone, Kanuma earth, pyrophyllite, talc, three-dimensional framework feldspar, zeolite, etc. In the composite system, metal oxide, polyvalent metal salt, insoluble heteropoly acid salt, insoluble hexacyanoferrate and the like can be mentioned.

Examples of the polyvalent metal salt include hydrotalcite compounds represented by the following formula (2).
M ²⁺ (1-X) M ^{3 + x} (OH ⁻ ) (2 + xy) (A ⁿ⁻ ) y / n (2)
However, in the formula (2), M ²⁺ is 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+. are shown, M ³⁺ represents at least one trivalent metal ion selected from the group consisting of Al ³⁺ and Fe ^3+, a ^n- represents an n-valent anion, 0.1 ≦ x ≦ 0 .5, 0.1 ≦ y ≦ 0.5, and n is 1 or 2.

The metal oxide is represented by the following formula (1).
MNxOn · mH ₂ O (1)
However, in Formula (1), x is 0-3, n is 1-4, m is 0-6, 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 It is a metal element and is different from each other.

  The metal oxide may be an unhydrated (non-hydrated) metal oxide in which m in the formula (1) can be represented by 0, or a hydrated (hydrated) metal in which m can be represented by a numerical value other than 0. It may be an oxide.

Further, when x in the above formula (1) is a numerical value other than 0, it is assumed that each metal element contained is distributed uniformly throughout the oxide with regularity. For example, a perovskite structure, a spinel structure, etc. are formed, and nickel ferrite (NiFe ₂ O ₄ ), zirconium hydrous ferrite (Zr · Fe ₂ O ₄ · mH ₂ O m is 0.5 to 6) Thus, the composite metal oxide is represented by a chemical formula in which the composition ratio of each metal element contained in the metal oxide is fixed.

When the adsorbent is an inorganic ion adsorbent, hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated from the point of excellent adsorption performance of phosphorus, boron, fluorine, arsenic Lanthanum oxide, hydrated 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 It is preferable to apply at least one metal oxide selected from the group consisting of activated alumina. Also preferred are aluminum sulfate-added activated alumina, aluminum sulfate-added activated carbon, and the like.
In addition, the metal oxide represented by the above formula (1) may be in a state in which a metal element other than M and N is dissolved. For example, in the case of the hydrated zirconium oxide represented by the formula ZrO ₂ · mH ₂ O in accordance with the formula (1), the hydrated zirconium oxide in which iron is dissolved may be used.
Moreover, the inorganic ion adsorbent may contain a plurality of types of metal oxides represented by the formula (1).

  The distribution state of the metal oxide in the inorganic ion adsorbent is not particularly limited. However, in order to make effective use of the properties of metal oxides and to provide an inorganic ion adsorbent with excellent cost performance, it must have a mixed structure in which a specific metal oxide is surrounded by another metal oxide. Is preferred. Examples of such a structure include a structure in which hydrated zirconium oxide covers the periphery of triiron tetroxide.

In addition, metal oxides include metal oxides in which other elements are dissolved, for example, a structure in which hydrated zirconium oxide in which iron is dissolved covers the periphery of triiron tetroxide in which zirconium is in solid solution. Are also preferred.
Hydrated zirconium oxide has high adsorption performance for ions such as phosphorus, boron, fluorine and 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 the adsorption is made of inexpensive iron trioxide, it can be used as an adsorbent having high adsorption performance, high durability performance, low cost and extremely excellent cost performance.

  From the viewpoint of obtaining an adsorbent with excellent cost performance for adsorption and removal of ions harmful to the environment and health such as phosphorus, boron, fluorine and arsenic, the inorganic ion adsorbent is represented by M and N in the formula (1). At least one of these is a metal element selected from aluminum, silicon, and iron, and around these metal oxides, at least one of M and N in formula (1) is titanium, zirconium, tin, cerium, lanthanum, A structure covered with an oxide of a metal element selected from the group consisting of yttrium is preferable.

In the above case, regarding the content ratio of the metal element selected from the group consisting of aluminum, silicon and iron in the inorganic ion adsorbent, the metal element selected from the group consisting of aluminum, silicon and iron, and titanium, zirconium and tin When the total number of moles of the metal element selected from the group consisting of cerium, lanthanum and yttrium is T, and the number of moles of the metal element selected from the group consisting of aluminum, silicon and iron is F, F / T (molar ratio) ) 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. Particularly preferred is 3 to 0.80.
This is because if the value of F / T (molar ratio) is excessive, the adsorption performance and durability performance tend to be low, and if the value is small, the effect on cost reduction is small.

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 tetroxide (FeO _1.33 · mH ₂ ) is considered due to the problem of oxidation stability in air. O) is preferred.

In addition, although an impurity element may mix in an inorganic ion adsorbent during the manufacturing process, there is no problem in the range which does not impair the function as an inorganic ion adsorbent.
Examples of impurity elements that may be mixed include nitrogen (nitrate, nitrite, ammonium), sodium, magnesium, sulfur, chlorine, potassium, calcium, copper, zinc, bromine, barium, hafnium, and the like. It is done.

As for the inorganic ion adsorbent, the specific surface area affects the adsorption performance and durability performance. For this reason, it is preferable to define the specific surface area within a certain range.
Specifically, it is preferable that the BET specific surface area determined by a nitrogen adsorption method is in the range of 20~1000m ² / g, more preferably 30~800m ² / g, is 50 to 600 m ² / g Is more preferable, and it is especially preferable that it is 60-500 m < ² > / g.
If the BET specific surface area of the inorganic ion adsorbent is too small, the adsorption performance is reduced. If the BET specific surface area is too large, the solubility in acids and alkalis is increased, and as a result, durability against repeated use is reduced.

The metal oxide represented by the above formula (1) can be produced by the following method.
For example, it can be obtained by filtering, washing and drying a precipitate obtained by adding an alkaline aqueous solution to an aqueous salt solution of the metal hydrochloride, sulfate, nitrate or the like.
In addition, a drying process is performed by air drying or a process for about 1 to 20 hours on the temperature conditions of about 150 degrees C or less, Preferably about 90 degrees C or less.

Next, at least one of M and N in the formula (1) is around at least one of M and N in the formula (1) around a metal oxide which 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 in which one side is covered with a metal oxide that is a metal element selected from the group consisting of titanium, zirconium, tin, cerium, lanthanum, and yttrium will be described.
In the following example, a case where an inorganic ion adsorbent having a structure in which the periphery of triiron tetroxide is covered with zirconium oxide will be described.

First, zirconium salt such as zirconium chloride, nitrate and sulfate and iron salt such as iron chloride, nitrate and sulfate have the desired F / T (molar ratio) described above. A mixed aqueous salt solution is prepared.
Thereafter, an alkaline aqueous solution is added to adjust the pH to 8 to 9.5, preferably 8.5 to 9, thereby generating a precipitate.
Thereafter, the temperature of the aqueous solution is adjusted to 30 to 80 ° C., preferably 40 to 60 ° C., and an oxidizing gas such as air is supplied while maintaining the pH at 8 to 9.5, preferably 8.5 to 9. Blowing is performed and oxidation is performed until ferrous ions cannot be detected in the liquid phase.
The resulting precipitate is filtered off, washed with water and then dried. The drying treatment is either air drying or a heat treatment at about 150 ° C. or lower, preferably about 90 ° C. or lower, for about 1 to 20 hours.
The moisture content after drying is preferably in the range of about 6 to 30% by weight.

Specific examples of the zirconium salt used in the production process include 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 2.0 mol per liter.
Examples of iron salts used in the production process include ferrous sulfates such as ferrous sulfate (FeSO ₄ ), ferrous nitrate (Fe (NO ₃ ) ₂ ), and ferrous chloride (FeC 1 ₂ ). Is 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.

Moreover, as an alkali used in the said manufacturing process, sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, sodium carbonate etc. are mentioned, for example. The alkaline aqueous solution is preferably 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 and the like, 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.

  The inorganic ion adsorbent prepared as described above can be used as it is packed in an adsorption tower, but usually has a small particle size and large pressure loss when packed in a column or the like and passed through. Often becomes. Therefore, it is preferable to adjust the particle size by granulating using a predetermined binder or the like.

Next, a suitable form as an adsorbent will be described.
The adsorbent filled in the adsorption tower is preferably a porous molded body.
The porous molded body includes an organic polymer resin and an inorganic ion adsorbent, has communication holes, and has a porous structure. Furthermore, there is no skin layer on the outer surface, and the surface has excellent openability.
Furthermore, it is assumed that there are voids in the fibrils forming the communication holes, and at least a part of the voids are opened on the fibril surface.

In addition, the outer surface opening ratio of the porous molded body constituting the adsorbent refers to the ratio of the sum of the opening areas of all the holes in the area of the visual field when the surface is observed with a scanning electron microscope. Specifically, when the outer surface aperture ratio was measured by observing the surface of the molded body at 10000 times, the range of the surface aperture ratio is preferably 10 to 90%, and particularly preferably 15 to 80%. preferable.
When the surface opening ratio is less than 10%, the diffusion rate of the substance to be adsorbed such as phosphorus into the molded body becomes slow. On the other hand, if it exceeds 90%, there arises a problem that the mechanical strength of the compact is insufficient. For this reason, it is preferable to set it as the said numerical range.
The outer surface opening diameter of the molded body is obtained by observing the surface with a scanning electron microscope as described above.
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 preferable range of the surface opening diameter of the hole is 0.005 μm to 100 μm, and particularly preferably 0.01 μm to 50 μm. If the thickness is less than 0.005 μm, the diffusion rate of the substance to be adsorbed such as phosphorus 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 constituting the adsorbent has voids in the fibrils forming the communication holes, and at least a part of the voids is open on the surface of the fibrils. The inorganic ion adsorbent described above is carried 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, and effectively functions as an adsorbent.
The porous molded body has an advantage that the fine adsorption site of the adsorption substrate is hardly blocked by the binder, and the function of the adsorption substrate is effectively exhibited.
In addition, the said fibril means the fibrous structure which consists of organic polymer resin, and forms the network structure continuous three-dimensionally on the outer surface and inside of a molded object.
The state of voids in the fibrils and the opening of the fibril surface can be determined by observing the cut section of the molded body with a scanning electron microscope. There are voids in the cross section of the fibril, and the surface of the fibril is open. I understand that.
Furthermore, it can be observed that the powder of 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.

In the porous molded body, the communication holes preferably have a maximum pore diameter layer in the vicinity of the surface of the molded body.
Here, the maximum pore diameter layer refers to the largest portion in the pore diameter distribution of the communication holes extending from the surface of the porous molded body to the inside.
If the porous molded body has large voids called voids or circular or oval (finger-like), the layer in which voids are present is the maximum pore diameter layer.
The vicinity of the surface of the molded body means the inside of the cleaved diameter of the molded body up to 25% from the outer surface toward the center. When the maximum pore diameter layer is in the vicinity of the surface of the molded body, the effect of accelerating the diffusion of the substance to be adsorbed into the inside is exhibited. That is, a substance to be adsorbed such as phosphorus 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 fractured surface of the molded body with a scanning electron microscope. As the hole diameter of the communication hole, the diameter is used when the hole is circular, and the equivalent circle diameter of a circle having the same area is used when the hole is not circular.
Although it does not specifically limit as a form of a porous molded object, For example, it can be set as arbitrary forms, such as a particulate form, a thread form, a sheet form, a hollow fiber form, a column shape, a hollow column shape. In particular, when the molded body is used as an adsorbent in the field of water treatment, a particulate form is preferable from the viewpoint of pressure loss when the water is filled in a column or the like, the effectiveness of the contact area, and the ease of handling. In particular, spherical particles (not only spherical but may be elliptical) may be preferable.

  The average particle diameter when the porous molded body is spherical is assumed to be the mode diameter (most frequent particle diameter) of the sphere equivalent diameter obtained from the angular distribution of the scattered light intensity of diffraction by laser light. The average particle size is preferably from 100 to 2500 μm, particularly preferably from 200 to 2000 μm. When the average particle size is less than 100 μm, the pressure loss tends to increase when the column or tank is filled. On the other hand, when the average particle size is larger than 2500 μm, the surface area becomes smaller when the column or tank is filled, and the processing is performed. Efficiency is reduced.

The porosity Pr (%) of the porous molded body is expressed by the following formula (3) 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. ).
Pr = (W1-W0) / (W1-W0 + W0 / ρ) × 100 (3)

  The porosity Pr (%) is preferably 50% to 90%, particularly preferably 60 to 85%. If it is less than 50%, the contact frequency between the adsorption target substance such as phosphorus and the inorganic ion adsorbent as the adsorption substrate tends to be insufficient. On the other hand, if it exceeds 90%, the strength of the molded product becomes insufficient.

The carrying amount of the inorganic ion adsorbent in the porous molded body is represented by the following formula (4), where the weight of the molded body when dried is Wd (g) and the weight of ash Wa (g).
Load (%) = Wa / Wd × 100 (4)

Here, the ash content is the residue when the molded body is baked at 800 ° C. for 2 hours. The supported amount is preferably 30 to 95%, more preferably 40 to 90%, and particularly preferably 65 to 90%. If the supported amount of the inorganic ion adsorbent is less than 30%, the contact frequency between the adsorption target substance such as phosphorus and the inorganic ion adsorbent as the adsorption substrate may be insufficient, while the supported amount is 95%. If it exceeds 1, the strength of the porous molded body may be insufficient.
By kneading the adsorbing substrate and the organic polymer resin and molding, 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 porous molded body is defined by the following formula (5).
Specific surface area (m ² / cm ³ ) = SBET × bulk specific gravity (g / cm ³ ) (5)
However, SBET is a specific surface area (m ² / g) per unit weight of the molded body.

The specific surface area can be measured using the BET method after vacuum drying the molded body at room temperature.
The bulk specific gravity is short in the form of particles, cylinders, hollow cylinders, etc., the wet volume is measured using an graduated cylinder etc., and the apparent volume is measured and then vacuum dried at room temperature. Obtained by determining the weight.
For long shapes such as thread, hollow fiber, and sheet, measure the cross-sectional area and length when wet, calculate the volume from the product of both, and then vacuum dry at room temperature to determine the weight Is obtained.

The specific surface area of the porous molded body is preferably in a range of ^{5m 2 / cm 3 ~500m 2 /} cm 3. When the specific surface area is less than 5 m ² / cm ³ , the amount of adsorption substrate supported and the adsorption performance tend to be insufficient. On the other hand, if the specific surface area exceeds 500 m ² / cm ³ , the strength of the molded body tends to be insufficient.

  Generally, the adsorption performance (adsorption capacity) of an inorganic ion adsorbent that is an adsorption substrate is often proportional to the specific surface area of the inorganic ion adsorbent. If the surface area of the inorganic ion adsorbent per unit volume of the porous molded body is small, the adsorption capacity and adsorption performance when packed in a column or tank are small, and it may be difficult to achieve high-speed processing.

The porous molded body preferably has a three-dimensional network structure in which fibrils are intricately intertwined.
In this case, since the fibril itself also has voids, the surface area becomes large. If an adsorption substrate (inorganic ion adsorbent) having a larger specific surface area is supported on this, the surface area per unit volume is also increased, and the function as an adsorbent is enhanced.

Next, the manufacturing method of a porous molded object is demonstrated.
The porous molded body is obtained by mixing an organic polymer resin, a good solvent thereof, an inorganic ion adsorbent, and a water-soluble polymer, and then molding and coagulating in a poor solvent.
Although it does not specifically limit as an organic polymer resin, The material applicable to the porosity-izing method by wet phase separation is preferable. 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.

The good solvent may be any material that can dissolve both the organic polymer resin and the water-soluble polymer, and is not particularly limited. For example, dimethyl sulfoxide (DMSO), N-methyl-2pyrrolidone (NMP), dimethylacetamide (DMAC), dimethylformamide (DMF), etc. are mentioned.
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 the content of the organic polymer resin in the good solvent is less than 5% by weight, the strength of the finally obtained molded article may be insufficient.
On the other hand, when it exceeds 40% by weight, it is difficult to obtain a porous molded body having a high porosity.

The water-soluble polymer is not particularly limited as long as it is compatible with the organic polymer resin described above.
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.

Further, as the water-soluble polymer, polyvinylpyrrolidone is particularly preferable from the viewpoint that the effect of developing a structure having voids inside the fibrils forming the communication holes is high.
The range of 2000-2 million is preferable, the range of 2000-1 million is more preferable, and the range of 2000-100000 is further more preferable for the weight average molecular weight of polyvinylpyrrolidone.
When 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. When the weight average molecular weight exceeds 2,000,000, the viscosity at the time of molding tends to increase and the molding tends to be difficult. There is.

The content of the water-soluble polymer in the porous molded body is expressed by the following formula (Wd (g) when the weight of the molded body is dried and Ws (g) is the weight of the water-soluble polymer extracted from the molded body. 6).
Content (%) = Ws / Wd × 100 (6)

Although content of water-soluble polymer is influenced by the kind and molecular weight of water-soluble polymer, 0.001 to 10% is preferable and 0.01 to 1% is more preferable.
If the content is less than 0.001%, the effect of opening the surface of the porous molded body may not be sufficiently obtained. On the other hand, if it exceeds 10%, the polymer concentration becomes relatively thin and practical. In addition, sufficient strength may not be obtained.

The weight Ws of the water-soluble polymer in the porous molded body can be 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 to extract the extracted water-soluble polymer. The weight of the conducting polymer is determined.
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 performed by infrared absorption spectrum (IR) or the like.
Furthermore, if there is a water-soluble polymer that remains in the fibrils and is not extracted, dissolve the porous molded body in a good solvent for both the organic polymer resin and the water-soluble polymer, and then remove the inorganic ion adsorbent. A liquid removed 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 in the porous molded body described above can be appropriately adjusted by changing 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, it becomes difficult to shift to the poor solvent side during molding, and the content becomes high.

As the poor solvent, for example, a liquid that does 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 can be used. Water is particularly preferred.
The coagulation rate can be controlled by adding a small amount of a good solvent for the organic polymer resin to the poor solvent.
0-40% is preferable and, as for the ratio of the good solvent mixed in water, 0-30% is more preferable.
When the mixing ratio exceeds 40%, the coagulation rate becomes slow. Therefore, when the polymer solution formed into droplets enters the poor solvent and moves in the poor solvent, it is between the poor solvent and the molded body. The shape tends to be distorted by the influence of friction resistance.

Although it does not specifically limit regarding the temperature of a poor solvent, The range of -30 degreeC-90 degreeC is preferable, More preferably, it is 0 degreeC-90 degreeC, More preferably, it is 0 degreeC-80 degreeC.
This is because 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 becomes difficult to stabilize.

When producing a porous molded body, the inorganic ion adsorbent is preferably a fine particle. In this case, the particle diameter is preferably 0.01 μm to 100 μm, more preferably 0.01 μm to 50 μm, and further preferably in the range of 0.01 μm to 30 μm.
When the particle size of the inorganic ion adsorbent is smaller than 0.01 μm, the slurry viscosity at the time of producing the porous molded body tends to increase, and molding tends to be difficult. On the other hand, when it is larger than 100 μm, the specific surface area of the inorganic ion adsorbent becomes small, so that the adsorption performance tends to be lowered.
In addition, 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 is a sphere equivalent diameter (most frequent particle diameter) obtained from the angular distribution of the scattered light intensity of diffraction by laser light.

Next, an ion processing method in the case where the above-described porous molded body is filled in an adsorption tower and used as an adsorbent will be described.
The porous molded body has a function of adsorbing and removing ions present in water by contacting with a liquid.
The adsorption target ions are not limited, and both anions and cations are targeted.
For example, in the anion, phosphorus (phosphate ion), fluorine (fluoride ion), arsenic (arsenate ion, arsenite ion), boron (borate ion), iodine ion, chlorine ion, sulfate ion, nitrate ion , 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, cesium, and the like.

Since the inorganic ion adsorbent exhibits specific selectivity for certain ions, the purpose is to remove specific ions such as phosphorus from the presence of various ions such as sewage and industrial wastewater. It is suitable for the case.
Specifically, in order to remove phosphorus, boron, fluorine, and arsenic ions, one or a mixture of two or more selected from the following groups (a) to (c) is used as the inorganic ion adsorbent. It is preferable to select.
(A) hydrated titanium oxide, hydrated zirconium oxide, hydrated tin oxide, hydrated cerium oxide, hydrated lanthanum oxide, and hydrated yttrium oxide.
(B) 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.
(C) Activated alumina.

In the above-described embodiment, the “adsorption means” typified by the adsorption tower is not limited at all, and may be configured to contact the adsorbent and the liquid to be treated.
When the adsorbent is filled in a predetermined container and used, the shape of the container and the shape of the packed layer of the porous molded body need only be able to contact the porous molded body and the liquid to be treated. Columnar, polygonal columnar, box-shaped containers can be applied.
However, the method of filling the column or adsorption tower as shown in FIGS. 1 to 7 and bringing the liquid to be treated into contact with each other increases the contact efficiency that is a characteristic of the porous molded body. It is excellent in that it can be pulled out sufficiently.
Moreover, it is preferable to provide a solid-liquid separation mechanism, for example, an eye plate or a mesh so that the porous molded body does not flow out of the container described above.
The material of the container is not particularly limited, but stainless steel, FRP (reinforced plastic with glass fiber), glass, various plastics, and the like are applied. In order to impart acid resistance, the inner surface may be lined with rubber or fluororesin.

The contact method between the porous molded body and the liquid to be treated is not particularly limited.
For example, when a packed bed of an adsorbent (porous molded body) is used as a fixed bed, a method of passing water in an upward flow or a downward flow through a 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 in the packed layer of the cylindrical porous molded body, an internal pressure system that allows water to flow in the opposite direction, and a horizontal flow through the box-shaped packed bed A method etc. are applicable.
The packed bed of the porous molded body may be a fluidized bed system.

It is preferable that the water treatment apparatus in the present embodiment includes a unit for solid-liquid separation of suspended substances in water as 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 can be sufficiently exhibited.
For example, coagulation sedimentation, sedimentation separation, sand filtration, and membrane separation are examples of the means for solid-liquid separation.
In particular, it is preferable to adopt a configuration that incorporates a membrane separation technique that requires a small installation area and provides clear filtered water.
Examples of membrane separation techniques include reverse osmosis membrane (RO), ultrafiltration membrane (UF), and microfiltration membrane (MF). The form of the membrane is not particularly limited, and can be variously applied, such as a flat membrane, a hollow fiber, a pleat, a spiral, and a tube.

Further, the pH of the liquid to be treated (raw water) is preferably adjusted to a suitable range in consideration of the combination of ions to be adsorbed and the inorganic ion adsorbent before being supplied to the water treatment apparatus.
For example, in the case of applying an inorganic ion adsorbent having a structure in which phosphorus in a liquid is to be adsorbed and hydrated zirconium oxide or iron tetroxide is covered with hydrated zirconium oxide, the pH range is pH 1.5 to 10. It is preferable to adjust to pH 2-7.
In addition, when applying an inorganic ion adsorbent having a structure in which boron in the liquid is to be adsorbed and hydrated cerium oxide or iron trioxide is covered with hydrated cerium oxide, the pH range is adjusted to pH 3-10. Preferably, the pH is preferably in the range of 5-8.

In addition, when applying an inorganic ion adsorbent having a structure in which fluorine is to be adsorbed and hydrated cerium oxide or iron tetroxide is covered with hydrated zirconium oxide, the pH range is adjusted to pH 1-7. It is preferable to adjust the pH to a range of 2 to 5.
When applying an inorganic ion adsorbent having a structure in which arsenic is adsorbed and hydrated cerium oxide or iron tetroxide is covered with hydrated cerium oxide, the pH range is preferably adjusted to pH 3-12. Furthermore, it is preferable to adjust the pH within the range of 5-9.

The porous molded body (adsorbent) can be reused by contacting with a predetermined desorption liquid to desorb the adsorbed anions and subsequently treating with an acidic aqueous solution.
By reusing in this way, the cost can be reduced and the amount of waste can be reduced.
Moreover, since the porous molded object is excellent in durability, it is suitable for repeated use.

An alkaline solution is used as the desorption liquid.
If the pH of the alkaline solution is pH 10 or higher, an effect of desorbing anions can be obtained, but it is preferably pH 12 or higher, more preferably pH 13 or higher.
The alkali concentration is preferably in the range of 0.1 wt% to 30 wt%, and more preferably in the range of 0.5 to 20 wt%. If the alkali concentration is less than 0.1 wt%, the effect of desorbing anions cannot be obtained sufficiently. On the other hand, if it exceeds 30 wt%, there will be no change in the desorption effect and the drug cost will increase.

The speed at which the alkaline aqueous solution as the desorption liquid is passed through is not particularly limited, but a normal flow rate SV of 0.5 to 15 (1 / hr) is preferable.
If it is slower than SV0.5, the desorption process takes a long time and is not practically efficient.
On the other hand, when the speed is higher than SV15, the contact time between the porous molded body and the alkaline aqueous solution becomes too short, and the desorption efficiency is lowered.

  The components of the desorption liquid are not particularly limited, and examples thereof include an inorganic alkali such as a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, and ammonium hydroxide, and organic amines. In particular, when a porous molded body adsorbing phosphorus ions in wastewater is desorbed with sodium hydroxide, sodium phosphate contained in the desorbed liquid is sodium hydroxide as a desorbed liquid from the viewpoint of relatively low solubility. Is preferred.

The alkaline aqueous solution as the desorption liquid is reused, and the desorbed ions are collected.
Specifically, an alkaline aqueous solution is brought into contact with the porous molded body that has adsorbed ions, and ions are eluted in the alkaline liquid. Subsequently, a target ion and a crystallization agent capable of causing precipitation are added to the ion eluent to generate a precipitate, which is removed.
As a result, the alkaline aqueous solution becomes reusable and ions can be recovered as a precipitate.

Examples of the crystallization agent include metal hydroxides.
Metal hydroxides combine with anions such as phosphorus, boron, fluorine, and arsenic to form metal salts and become precipitates.
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 of the crystallization agent include sodium hydroxide, aluminum hydroxide, magnesium hydroxide, and calcium hydroxide.

The crystallization agent is preferably a polyvalent metal hydroxide from the viewpoint of obtaining a hardly soluble precipitate, that is, a precipitate having low solubility.
Among the above, aluminum hydroxide, magnesium hydroxide, and calcium hydroxide are particularly preferable, and calcium hydroxide is preferable from the viewpoint 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 (7).
2NaF + Ca (OH) ₂ → 2NaOH + CaF ₂ ↓ (7)

Similarly, when it exists as sodium phosphate in the eluent, alkali can be recovered according to the following reaction formula (8).
Furthermore, the crystallized calcium phosphate can be recycled into fertilizers and the like.
6Na ₃ PO ₄ + 10Ca (OH) ₂ → 18NaOH + Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ ↓ (8)

The amount of metal hydroxide added as the crystallization agent is preferably 1 to 4 times equivalent to the target ion. When the amount added is equal to or less than the equimolar amount, the precipitation removal efficiency is deteriorated. When the amount exceeds 4 times the equivalent, the removal efficiency is hardly changed, which is disadvantageous in terms of cost.
The pH of the liquid in the step of removing the precipitate is preferably 6 or more, and considering that the aqueous alkaline solution is recovered and reused, it is preferably maintained at pH 12 or more, more preferably pH 13 or more. In addition, when pH is less than 6, the solubility of a precipitate will become large and precipitation efficiency will fall. In the step of removing the precipitate, in addition to the metal hydroxide, an inorganic flocculant such as aluminum sulfate or polyaluminum chloride, or a polymer flocculant may be used in combination.

Furthermore, as described above, in the step of recovering the desorbed ions, it is preferable to cool the desorbed liquid from which the ions have been desorbed to crystallize and remove the precipitate.
Such a step of cooling the desorption liquid is particularly suitable when the porous molded body adsorbing phosphate ions is desorbed using sodium hydroxide.
The cooling means is not particularly limited, and a normal chiller or heat exchanger can be applied.
The cooling temperature is not particularly limited as long as it is a temperature at which desorbed ions can be crystallized. For example, the temperature is preferably 5 to 25 ° C, and more preferably 5 to 10 ° C.
If it is less than 5 ° C, it is disadvantageous in cost, and if it exceeds 10 ° C, the effect of crystallizing the precipitate may not be sufficiently obtained.
In order to effectively crystallize sodium phosphate by cooling, sodium hydroxide may be newly added to increase the concentration of sodium hydroxide in the desorption liquid.

The solid-liquid separation method of the precipitate is not particularly limited, but usually, sedimentation separation, centrifugation, belt press machine, screw press machine, membrane separation method and the like can be applied.
In particular, the membrane separation method is preferred from the viewpoint that the installation area is small and clear filtered water can be obtained.
For the membrane separation method, for example, an ultrafiltration membrane (UF), a microfiltration membrane (MF), a dialysis membrane or the like can be applied. The form of the membrane may be any of a flat membrane, a hollow fiber, a pleat, a tube shape, etc., and is not limited.
Of the membrane separation methods, ultrafiltration membranes (UF), microfiltration membranes (MF) and the like are preferable from the viewpoint of filtration speed and accuracy.

After the ion desorption process described above is completed, the porous molded body is alkaline.
In this state, since the ability to adsorb ions in the liquid to be treated again is low, it is necessary to perform an operation of returning the pH around the porous molded body to a predetermined value using an acidic aqueous solution, that is, an activation treatment. There is.
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 0.001 to 10 wt%. If the concentration is less than 0.001 wt%, it takes too much time to complete the activation, which is disadvantageous in cost. On the other hand, when the concentration exceeds 10 wt%, there is a possibility that a problem may occur in terms of handling danger of the acidic aqueous solution.
Although there is no restriction | limiting in particular about the flow rate of acidic aqueous solution, The range of SV0.5-30 (1 / hr) is preferable. If the SV is less than 0.5, it takes too much activation time. On the other hand, if it exceeds SV30, the contact time between the porous molded body and the acidic aqueous solution is shortened, and a sufficient activation effect may not be obtained.

In the activation treatment, a system in which an acidic aqueous solution for activation treatment circulates between an adsorption tower (or a predetermined space such as a column) with a porous molded body and a predetermined pH adjustment tank. It is preferable to apply.
By setting it as such a system, the pH of the porous molded object which shifted to the alkali side through the ion desorption process can be gradually returned to a desired 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 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, there is a drawback in that it is necessary to use a large amount of processing liquid and a long processing time is required.
In view of such a problem, in the activation treatment of the porous molded body, it is possible to provide a pH adjusting tank separately from the predetermined space where the porous molded body is located so as to circulate the activation liquid. desirable. Thereby, the whole structure of an apparatus can be reduced in size and an activation liquid can be utilized effectively. In general, the range of SV1 to 200 (1 / hr) is preferable for the liquid passing speed, and further, the range of SV10 to 100 is preferable. If the flow rate is less than SV1, the activation process takes too much time. On the other hand, if it exceeds SV200, pump power is required, which is disadvantageous in terms of cost.

The ion desorption process and the activation process described above can be performed in a state where the porous molded body is filled with the adsorbent.
That is, after the operation of adsorbing the liquid to be treated (raw water) is completed, the alkaline aqueous solution and the acidic aqueous solution are passed in order, so that the liquid can be easily regenerated. In this case, the liquid flow direction may be either an upward flow or a downward flow.

  Since the porous molded body is excellent in chemical resistance and strength, even if this regeneration treatment is repeated several tens to several hundreds of times, the ion adsorption performance hardly decreases.

Next, specific examples and comparative examples will be described.
Example 1
First, a porous molded body was manufactured.
10 g of ethylene vinyl alcohol copolymer (EVOH, Nippon Synthetic Chemical Industry Co., Ltd., Soarnol E3803 (trade name)), 10 g of polyvinyl pyrrolidone (PVP, BASF Japan Ltd., Luvitec K30 Powder (trade name)), dimethyl sulfoxide ( DMSO, Kanto Chemical Co., Ltd. (80 g) was put into a Separa flask, heated to 60 ° C. and dissolved to obtain a uniform polymer solution.
To 100 g of this polymer solution, 60 g of zirconium oxide powder (Iwatani Corporation) was added as an inorganic ion adsorbent and mixed well to obtain a composite polymer slurry.

  The composite polymer slurry is 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 is rotated, and droplets are formed 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 composite polymer slurry was coagulated. Then, washing | cleaning and classification were performed and the spherical molded object with an average particle diameter of 550 micrometers was obtained. The spherical molded body was immersed in a sulfuric acid acidic solution having a pH of 3 to perform an activation treatment, thereby obtaining an adsorbent as a porous molded body.

In this example, the water treatment apparatus having the configuration shown in FIG. 1 was used.
First, sewage secondary treated water at the sewage purification center is passed through a sand filtration bed composed of silica sand having a particle size of 0.6 mm and anthracite having a particle size of 1.5 mm at a speed of SV40 (1 / hr) in advance. (Floating solid content) was removed, and trisodium phosphate (Na ₃ PO ₄ .12H ₂ O) was dissolved in the solution to prepare a solution having a phosphorus concentration of 1.0 mg-P / liter. This was used as raw water 1 in FIG. The pH of the raw water was 7.8.

4 ml of the porous molded body produced as described above was packed in adsorption towers A, B and C each having an inner diameter of 10 mm.
As the detector D8, a pH meter (manufactured by Horiba, F-22) and a phosphorus concentration meter (manufactured by HACH, Phosfax Compact) were installed, and the quality of the treated water 2 after the treatment was measured.

First, the state of each valve constituting the water treatment apparatus was controlled so that the liquid flow indicated by the arrow in FIG. Specifically, the valve V1-open, the valve V5-open, the valve V8-open, and the others were closed.
In this state, water was passed at a speed of SV40 (1 / hr).
That is, the raw water 1 is passed through the detector D1, the valve V1, the adsorption tower A, the valve V8, the detector D3, the adsorption tower B, the valve V5, and the detector D8 in this order.
In this case, the relationship between the water passage time and the pH and phosphorus concentration of the treated liquid (treated water) is shown in the region A → B in FIG.

Subsequently, when the phosphorus concentration exceeded 0.3 mg-P / liter (ppm) in the detector D8, the valve was switched, and a so-called reverse feed process was performed as shown in FIG.
Specifically, valve V1-closed, valve V2-closed, valve V3-opened, valve V4-closed, valve V5-opened, valve V6-closed, valve V7-closed, valve V8-closed, valve V9-closed, Valve V10-closed, valve V11-opened, and valve V12-closed. In this state, the raw water 1 was passed through the detector D1, the valve V3, the adsorption tower C, the valve V11, the detector D6, the adsorption tower B, the valve V5, and the detector D8 in this order.
That is, water was passed from the adsorption tower C located at the rear stage to the adsorption tower B located at the front stage so as to be in the reverse direction with respect to the predetermined order of use.
In this case, the relationship between the water passage time and the pH and phosphorus concentration of the treated liquid (treated water) is shown in the region C → B in FIG.

With respect to the treated water 2 obtained in the reverse feeding step performed by the apparatus configuration shown in FIG. 3, the pH was measured and monitored by the detector D8. When the pH reached the discharge standard (pH 5.8), the flow path was switched, the water flow direction was returned to the forward direction, and the second adsorption removal step was performed.
The state of each valve in this case is shown in FIG.
Specifically, valve V1-closed, valve V2-opened, valve V3-closed, valve V4-closed, valve V5-closed, valve V6-opened, valve V7-closed, valve V8-closed, valve V9-closed, Valve V10-open, valve V11-closed, and valve V12-closed. In this state, the raw water 1 was passed through the detector D1, the valve V2, the adsorption tower B, the valve V10, the detector D5, the adsorption tower C, the valve V6, and the detector D8 in this order.
That is, water was passed from the adsorption tower B located at the front stage to the adsorption tower C located at the rear stage so as to be in the forward direction.
In this case, the relationship between the water flow time and the pH and phosphorus concentration of the treated water is shown in the region of B → C in FIG.

  As shown in FIG. 8, the phosphorus concentration of the treated liquid (treated water) is maintained at 0.5 mg-P / L or less, a good treated state is maintained, and the treated water is released as a reference (pH 5.8). It was confirmed that less than

(Comparative Example 1)
Although the water treatment apparatus of the structure shown in FIG. 1 was used, the reverse feed process as shown by the arrow in FIG. 3 was not performed. That is, even if the adsorption tower was switched, only the adsorption removal process was continued.
For other conditions, water was passed in the same manner as in Example 1 described above.
FIG. 9 shows changes in pH and phosphorus concentration of treated water in this case.
According to this example, when the flow path of the adsorption tower A → the adsorption tower B is switched to the adsorption tower B → the adsorption tower C, the pH of the treated water exceeds the lower limit (pH 5.8) of the discharge standard. I have. This is because the adsorbent in the latter adsorption tower C functions excessively and relaxation by reverse feeding is not performed.

(Comparative Example 2)
In the activation treatment for the adsorbent packed in the adsorption tower C, the pH was adjusted to 6 using sulfuric acid to intentionally make the activity insufficient.
Other conditions were such that water was passed in the same manner as in Comparative Example 1 above.
The pH of the treated water and the change in phosphorus concentration in this case are shown in FIG.
According to this example, when the flow path is switched from the water passing through the adsorption tower A → the adsorption tower B to the adsorption tower B → the adsorption tower C, the pH of the treated water is lowered. Excessive activation was prevented because the adsorbent activation was intentionally inadequate.
However, if the water flow is continued, the phosphorus concentration of the treated water immediately rises, which is insufficient in practice from the viewpoint of the effect of removing phosphorus.

(Example 2)
First, a porous molded body is manufactured.
As the inorganic ion adsorbent, cerium oxide powder (Iwatani Corporation) was used instead of zirconium oxide powder. Other conditions were the same as in the method for producing a porous molded body in Example 1, and a spherical porous molded body having an average particle size of 550 μm was obtained. This porous molded body was immersed in an acidic solution of hydrochloric acid having a pH of 3, and subjected to an activation treatment to obtain an adsorbent.
In this example, the water treatment apparatus having the configuration shown in FIG. 1 was used.
First, sodium fluoride (NaF) was dissolved in sewage secondary treated water at the sewage purification center to prepare a liquid having a fluorine concentration of 8 mg-F / L to be raw water 1.
The detector used was a device (IC-7000, manufactured by Yokogawa Analytical Systems) having a function of measuring the fluorine concentration by ion chromatography.
The other conditions were the same as in Example 1 and the water flow test was performed.
That is, water is passed in the forward direction of the adsorption tower A → the adsorption tower B, then water is passed in the reverse direction in the direction of the adsorption tower C → the adsorption tower B, and then the forward direction of the adsorption tower B → the adsorption tower C. The water was passed through.
In this example, the fluorine concentration of the treated water 2 is maintained at 0.5 mg-F / L or less in both the forward direction and the reverse direction, and a good treatment state can be maintained. Was confirmed. Moreover, since the active state of the adsorption tower which became a new latter stage by the reverse feeding process was appropriately relaxed, the pH of the treated water became less than the discharge standard (pH 5.8), and the water treatment was continued in a desirable state. It was confirmed that

  The water treatment apparatus of the present invention and the water treatment method using the same can be widely used to treat various industrial wastewater discharged from sewage factories, food factories, chemical factories, etc., domestic wastewater, etc. is there.

It is the schematic diagram which showed the typical structure of the water treatment apparatus. It is a schematic diagram which shows the liquid flow state in the adsorption removal process of the 1st step. It is a schematic diagram which shows the liquid flow state in the reverse sending process performed as a pre-process of the adsorption removal process of a 2nd step | paragraph. It is a schematic diagram which shows the liquid flow state in the 2nd adsorption removal process. It is a schematic diagram which shows the liquid flow state in the reverse feed process performed as a pre-process of the adsorption removal process of the 3rd step | paragraph. It is a schematic diagram which shows the liquid flow state in the 3rd step | paragraph adsorption removal process. It is a schematic diagram which shows the liquid flow state of the reverse feed process performed as a pre-process of the adsorption removal process of the 1st step | paragraph. It is the figure which showed the time change of pH in Example 1, and the time change of phosphorus concentration. It is the figure which showed the time change of pH in Comparative Example 1, and the time change of phosphorus concentration. It is the figure which showed the time change of pH and the time change of phosphorus concentration in the comparative example 2. It is the schematic diagram which showed the typical structure of the conventional water treatment apparatus.

Explanation of symbols

V1-V12 valve D1-D8 detector

Claims (8)

Three or more adsorbing means that are filled with an adsorbent capable of adsorbing substances contained in the liquid to be treated and whose use sequence is cyclically determined;
Of the adsorbing means, any two units in which the order of use is continuous are connected in series according to the order of use, and the forward feeding means for transferring the liquid to be treated in a direction according to the order of use;
Means for supplying the liquid to be treated to the preceding stage of the two adsorption means;
Subsequent to the preceding stage, a means for recovering the treated liquid in which the substance contained in the liquid to be treated is adsorbed via the latter stage of the two adsorption means;
With the breakthrough of the previous stage, the subsequent stage is set to the two previous stages in which the order of use is continued, and the adsorbing means following the subsequent stage in accordance with the use order is set to be the subsequent stage of the new two units, the order of use. Switching means for repeatedly switching the adsorption means according to
As a pre-stage for supplying the liquid to be processed to the two previous stages switched by the switching means, the liquid to be processed is supplied to the subsequent stage of the two new units, A water treatment apparatus comprising: a reverse feeding means for transporting and collecting.   Water quality detection means for detecting the water quality of the liquid to be treated both when the liquid to be treated is transferred by the progressive means and when the liquid to be treated is transferred by the reverse means. The water treatment apparatus according to claim 1.   The water treatment apparatus according to claim 1 or 2, wherein the adsorbent contains at least an inorganic ion adsorbent. The water treatment apparatus according to claim 3, wherein the inorganic ion adsorbent contains at least one metal oxide represented by the following formula (1).
MNxOn · mH ₂ O (1)
(However, in Formula (1), x is 0-3, n is 1-4, m is 0-6. M and N are Ti, Zr, Sn, Sc, Y, La, Ce, Pr, From the group consisting of Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Si, Cr, Co, Ga, Fe, Mn, Ni, V, Ge, Nb, and Ta (Selected metal elements and different from each other.) The water treatment apparatus according to claim 4, wherein the metal oxide is one or a mixture of two or more selected from any of 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) 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.
(C) Activated alumina. The adsorbent contains at least an organic polymer resin and the inorganic ion adsorbent, and is a porous molded body having communication holes that open to the outer surface.
There is a void inside the fibril forming the communication hole, and at least a part of the void is open at the surface of the fibril, and the inorganic ion adsorption on the outer surface and the inner void surface of the fibril The water treatment apparatus according to any one of claims 3 to 5, wherein a body is supported. Three or more adsorbing means that are filled with an adsorbent capable of adsorbing substances contained in the liquid to be treated and whose use sequence is cyclically determined;
Of the adsorbing means, any two units in which the order of use is continuous are connected in series according to the order of use, and the forward feeding means for transferring the liquid to be treated in a direction according to the order of use;
Means for supplying the liquid to be treated to the preceding stage of the two adsorption means;
Subsequent to the preceding stage, a means for recovering the treated liquid in which the substance contained in the liquid to be treated is adsorbed via the latter stage of the two adsorption means;
With the breakthrough of the previous stage, the subsequent stage is set to the two previous stages in which the order of use is continued, and the adsorbing means following the subsequent stage in accordance with the use order is set to be the subsequent stage of the new two units, the order of use. Switching means for repeatedly switching the adsorption means according to
As a pre-stage for supplying the liquid to be processed to the two previous stages switched by the switching means, the liquid to be processed is supplied to the subsequent stage of the two new units, A water treatment method using a water treatment device comprising a reverse feed means for transporting and collecting,
A step of supplying the liquid to be treated to a preceding stage of the two adsorption means by the sequential feeding means, and collecting a treated liquid after the adsorption process is performed via the two subsequent stages; ,
With the breakthrough of the preceding stage, the latter stage is used as two new preceding stages in the order of use, and the adsorbing means following the latter stage according to the order of use is set as the second stage of the new use. Switching repeatedly according to the order;
As a pre-stage of supplying the liquid to be processed to the two previous stages by the reverse feeding means, the liquid to be processed is supplied to the two subsequent stages of the new two groups, and then the two previous stages of the new two groups. The water treatment method which has a reverse feed process which transfers to and collects.   8. The water treatment method according to claim 7, wherein the reverse feeding step is finished in a state where the liquids to be treated collected from the two previous stages satisfy the discharge standard.

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