JP2006192422A - Method for producing water suitable for drinking by reducing boron content in water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing water suitable for drinking by reducing a boron content in water. <P>SOLUTION: Boron-containing water is passed through a reverse osmosis membrane separator, next the water permeating into the membrane and discharged from the apparatus is passed through an apparatus packed with a chelate formative fiber having chelate formation ability to a boron element and a boron compound, and a remaining boron content is reduced during permeating into the membrane. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing water suitable for drinking by reducing the boron content in water. In particular, the present invention relates to a method for reducing the boron content in water, such as seawater and brackish water desalination treatment and purified (upper) water treatment. The present invention also relates to a method of producing mineral-containing water suitable for drinking with a reduced boron content. Furthermore, the present invention relates to a method for producing water in which the boron content is reduced and solutes such as salts are concentrated and monovalent ion concentrated water in which monovalent ions are concentrated.

  In recent years, seawater desalination projects using reverse osmosis membranes (hereinafter referred to as RO membranes) have been promoted in order to secure new water sources. In areas where there is only well water and the water quality is poor, purification is performed using RO membranes. If RO membranes are used to purify seawater, etc., 90% or more of the solute is removed except for some of the boron, etc., so it almost meets the standard or guideline values for tap water quality management items excluding boron. Water quality fresh water can be obtained.

  Boron is contained, for example, in seawater at about 5 mg / l (differs slightly depending on the analysis method), and the boron concentration of the produced water by the conventional seawater desalination RO membrane is about 0.8 to 1.5 mg / l (water temperature). , Depending on the quality of raw water). Generally, about 0 to 2 mg / l of boron is also contained in naturally occurring fresh water.

  Regarding boron, in the Ministerial Ordinance on Water Quality Standards enforced on April 1, 2004 based on the provisions of the Water Supply Act of Japan, boron and its compounds are 1.0 mg / l or less in terms of the amount of boron. (World Health Organization) drinking water quality guidelines show a provisional value of 0.5 mg / l or less, and even South Korea, which seems to have set the strictest value, shows even 0.3 mg / l or less. The requirement of Japanese tap water quality standards regarding the amount of boron is gradual worldwide, and it must be lowered early.

  As a boron removal method, seawater is passed through the RO membrane, the membrane permeate from which solutes such as boron have been removed is taken out, this membrane permeate is passed through the cation exchange resin layer, and remains in the membrane permeate. A water treatment method has been proposed in which boron to be removed is removed by ion exchange (see, for example, Patent Document 1). However, when boric acid is selectively captured from seawater by a boron-selective adsorption ion exchange resin, there are an outer peripheral surface and pores as sites that function for ion exchange. Since all functional groups cannot contribute to ion exchange, the effective utilization rate of the ion exchange resin as a whole is extremely low, and the absolute amount of elements capable of ion exchange must be insufficient. In addition, since the ion exchange resin captures ionic cations and anions, it captures metal ions other than boron, and the ion exchange performance quickly decreases. Further, in the conventional granular ion resin, since the diffusion into the pores is slow as described above, a sufficient removal effect cannot be obtained unless it is brought into contact with the non-treatment liquid for a considerably long time. However, if the particle size is made too small in order to increase the effective specific surface area, the pressure loss increases.

  On the other hand, a novel fiber having chelating ability with metals such as boron or their compounds has been proposed (see, for example, Patent Document 2). This chelate-forming fiber has excellent trapping performance for metal elements such as boron or their compounds, but does not have chelate-forming ability for other metal ions. Therefore, this chelate-forming fiber alone cannot be used to desalinate seawater or the like to make it desalinated.

  Thus, it is strongly desired to reduce the boron content in drinking water.

  Seawater and the like are resources that are rich in minerals such as potassium, calcium, and magnesium necessary for humans. It would be desirable if mineral-containing water rich in minerals suitable for direct drinking could be produced from such mineral-rich resources.

Furthermore, it would be desirable if water with reduced boron content and concentrated solutes such as salt and monovalent ion-enriched water with concentrated monovalent ions could be produced from seawater or the like.
Japanese Patent Laid-Open No. 10-15356 No. 98-42910

  In view of the above circumstances, an object of the present invention is to provide a method for easily reducing the boron content in drinking water. The object of the present invention is also to provide a method for producing mineral-containing water suitable for drinking. Another object of the present invention is to provide a method for producing a concentrated water in which the boron content is reduced and a solute such as a salt is concentrated and a monovalent ion concentrated water in which a monovalent ion is concentrated.

  The present inventor found that the boron content can be easily reduced by using a boron-selective chelate-forming fiber in seawater desalination and boron-containing water treatment, and the present invention has been completed. It came to do. In addition, the present inventors have found that mineral-containing water rich in useful minerals can be directly produced by removing a salt such as sodium chloride from seawater or the like and simply reducing the boron content. The present invention has been completed. Furthermore, the present inventor has found that it is possible to easily reduce the boron content of concentrated water enriched with solutes obtained from seawater or the like and monovalent ion concentrated water enriched with monovalent ions. The present invention has been completed.

Thus, according to the present invention, the following inventions 1 to 12 are provided.
1. The boron-containing water is passed through a reverse osmosis membrane separation device, the water that has permeated the membrane and exited the device is then passed through a device filled with chelating fibers that have chelating ability to boron and its compounds, and the membrane A method for producing water suitable for drinking by reducing the boron content remaining in permeated water.
2. Boron-containing water is passed through a device filled with chelating fibers that have chelating ability for boron and its compounds to reduce the boron content, and then passed through a reverse osmosis membrane separator to produce a solute that permeates the membrane. A method for producing removed drinking water and non-permeated water in which a solute is concentrated without passing through a membrane.
3. Boron-containing water is passed through an electrodialyzer, and demonovalent ionized water from which monovalent ions have been removed is then passed through a device filled with chelate-forming fibers having excellent chelate-forming ability for boron and its compounds. A method for producing mineral-containing water suitable for drinking by reducing the boron content remaining in demonovalent ionized water.
4). Boron-containing water is passed through a device filled with chelating fibers having excellent chelating ability for boron and its compounds to reduce the boron content and then passed through an electrodialyzer to remove monovalent ions. A method for producing mineral-containing water suitable for drinking and monovalent ion-enriched water enriched with monovalent ions.
5. 5. The method according to any one of 1 to 4 above, wherein the chelate-forming fiber is obtained by binding a chelate functional group to the fiber by a chemical reaction.
6). 5. The method according to 3 or 4 above, wherein the electrodialyzer uses a monovalent ion selective membrane as a cation membrane.
7). The method according to any one of 1 to 6 above, wherein the boron-containing water is seawater or brine.
8). 8. The method according to any one of the above 1, 2, 5, and 7, wherein water suitable for drinking has a boron content of 1.0 mg / l or less and hardly contains minerals.
9. The mineral-containing water suitable for drinking is the method according to any one of 3 to 7 above, wherein the boron content is 1.0 mg / l or less and monovalent ions are selectively reduced.
10. 10. The method according to 8 or 9 above, wherein the boron content is 0.5 mg / l or less.
11. The method according to 10 above, wherein the boron content is 0.3 mg / l or less.
12 The chelate-forming fiber has a group having an amino group and at least two hydroxyl groups bonded to carbon in a fiber molecule, and is directed to boron or a compound thereof. The method as described in any one.

  According to the present invention, the boron concentration in the boron-containing water can be reduced easily and efficiently, and the requirements of the drinking water quality standard regarding the amount of boron can be satisfied worldwide. In addition, it is possible to easily obtain mineral-containing water suitable for drinking that contains abundant minerals such as potassium, calcium, and magnesium necessary for humans with a reduced boron content. From this, even if it mix | blends drinking water and mineral containing water in arbitrary ratios, the requirement of the water quality standard regarding the quantity of boron can be satisfied worldwide. Furthermore, it is possible to easily obtain concentrated water in which the boron content is reduced and solutes such as salts are concentrated and monovalent ion concentrated water in which monovalent ions are concentrated.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a water treatment device that treats treated water 1 containing boron, such as seawater, includes a pretreatment device 2 such as a filtration tank, a membrane separation device 3 provided with an RO membrane, and chelate formation as necessary. And a fiber-filled tower 4.

  The chelate-forming fiber packed tower 4 is formed by filling a boron-selective chelate-forming fiber bed 5 inside.

  When processing with such a water treatment device, the treated water 1 is introduced into the pretreatment device 2 as necessary and subjected to microfiltration and the filtered water 6 from which suspended substances are sufficiently removed is obtained. obtain. This filtered water 6 is supplied to the RO membrane of the membrane separation device 3, and solutes such as boron in the filtered water 6 are removed by membrane separation. Water in which these solutes have been reduced by passing through the RO membrane is obtained as permeated water 7, and water concentrated without these solutes permeating through the RO membrane is obtained as non-permeated water 9.

  This RO membrane permeated water 7 is further introduced into the chelate-forming fiber packed tower 4 and passed through the chelate-forming fiber bed 5 to remove boron by forming a chelate with boron remaining in the RO membrane permeated water 7. Then, treated water 8 is obtained.

  The treated water 8 thus obtained contains almost no boron or other solute, and the boron content is 1.0 mg / l or less of Japanese tap water quality standard, and further, a WHO beverage. The water quality guideline is 0.5 mg / l or less, and is still well below the water quality standard of 0.3 mg / l or less in Korea, or below the detection limit.

  When performing seawater desalination according to this embodiment, the target value of boron in the treated water 8 is set to, for example, 0.1 mg / l or less, and the boron concentration in the treated water 8 is continuously detected. When the boron concentration in the treated water 8 exceeds 0.1 mg / l, the chelate-forming fiber bed is replaced.

  The exchange of the chelate-forming fiber bed capturing boron has, for example, two or more chelate-forming fiber packed towers 4 in parallel, and the supply of the RO membrane permeate 7 to the chelate-forming fiber bed capturing boron is stopped. Then, it is preferable to start supplying the RO membrane permeated water 7 to another chelate-forming fiber packed tower. While supplying RO membrane permeate 7 to another chelating fiber packed tower, the chelating fiber bed that has captured boron can be removed from the packed tower and filled with new chelating fiber. . Further, while supplying RO membrane permeated water 7 to another chelate-forming fiber packed tower, chelate is formed by treating the chelate-forming fiber bed capturing boron with a strong acid aqueous solution such as hydrochloric acid or sulfuric acid. Thus, the trapped boron can be easily separated and thereby easily regenerated.

  In the membrane separation device 3, as the RO membrane, for example, a cellulose acetate membrane, a synthetic polymer membrane (polyvinyl, crosslinked aramid, crosslinked polyamide, etc.) can be used. Various RO membranes such as a hollow fiber type and a spiral type can be used, and it is convenient to use a module shape.

  The chelate-forming fibers used in the present invention are known per se. The chelate-forming fiber is a fiber in which a chelate functional group is bonded to the fiber by a chemical reaction. In the present invention, a chelate-forming fiber having excellent chelate-forming ability for boron is used. Examples of such chelate functional groups are described in, for example, Patent Document 2, and chelate-forming fibers obtained by binding such chelate functional groups by chemical reaction may be used in the present invention.

［式中、Ｇは糖アルコール残基または多価アルコール残基、Ｒは水素原子、アルキル基または−Ｇ(Ｇは上記と同じ意味を表わし、上記Ｇと同一もしくは異なる基であってもよい)を表わす］。 Such chelating fibers have groups in the fiber molecule with amino groups and two or more hydroxyl groups, especially at least two hydroxyl groups bonded to adjacent carbons, such as boron and There are fibrous chelate scavengers that have excellent chelating ability for the compounds.
A preferred group introduced into the fiber molecule in order to provide chelating ability with the boron or its compound can be represented by the following general formula [1]:

[Wherein, G represents a sugar alcohol residue or a polyhydric alcohol residue, R represents a hydrogen atom, an alkyl group, or -G (G represents the same meaning as described above, and may be the same as or different from G). Represents].

  Among these, G in the formula [1] is particularly preferably a residue obtained by removing an amino group from D-glucamine or a dihydroxypropyl group, and R is hydrogen or a lower alkyl group.

  A preferred group introduced into the fiber molecule in order to give chelating ability with these boron and its compounds (hereinafter sometimes referred to as metal-like chelate formability) is a reactive functional group (hydroxyl group) in the fiber molecule. , An amino group, an imino group, an aldehyde group, a carboxyl group, a thiol group, or the like), or may be indirectly bonded by a cross-linking bond. As the base fiber, any of natural fiber, regenerated fiber, and synthetic fiber can be used, but natural fiber or regenerated fiber is particularly preferable for efficiently introducing the group having the chelate forming ability as described above. Fiber.

  A method for producing such a metal chelate-forming fiber is described in Patent Document 2.

  In the present invention, as the boron chelate-forming fibers, for example, those commercially available as Kirest Fibers GCP, GRY, GRY-L, GRY-LW, etc. from Kirest Corporation can be suitably used. In particular, it is preferable to use a Kirest fiber GRY-LW.

  A modification of the first embodiment of the present invention is shown in FIG. When the treatment is performed according to this deformation, the treated water 11 is introduced into the pretreatment device 12 as necessary and subjected to microfiltration to obtain filtered water 16 from which suspended substances are sufficiently removed. The filtered water 16 is introduced into the chelate-forming fiber packed tower 14 and passed through the chelate-forming fiber bed 15 to form boron and chelate to remove boron. Water 17 with reduced boron content exiting the chelate-forming fiber packed tower 14 is supplied to the RO membrane of the membrane separation device 13, and solutes such as salts in the water 17 are removed by membrane separation. Water that has been permeated to reduce these solutes is obtained as permeated water 18, and water that is concentrated without these solutes permeating the RO membrane is obtained as non-permeated water 19.

  The permeated water 18 thus obtained contains almost no boron or other solutes, and the boron content is 1.0 mg / l or less of Japanese tap water quality standard, and further, a WHO beverage. The water quality guideline is 0.5 mg / l or less, and is still well below the water quality standard of 0.3 mg / l or less in Korea, or below the detection limit. Further, the non-permeated water 19 contains a solute such as a salt in a concentrated manner, and hardly contains boron. Accordingly, the non-permeated water 19 can be effectively used in the food, pharmaceutical and cosmetic fields without further deboronation treatment.

  When performing seawater desalination according to the modification of the first embodiment, the boron concentration in the water 17 exiting the chelate-forming fiber packed tower 14 is continuously detected, and the boron concentration in the water 17 is When a certain value is exceeded, the chelating fiber bed is replaced. Such an operation is performed in the same manner as described in the first embodiment.

  Next, a second embodiment of the present invention will be described with reference to the drawings. In FIG. 3, a water treatment device for treating the water to be treated 101 containing boron, such as seawater, includes a pretreatment device 102 such as a filtration tank, an electrodialysis device 103, and a chelate-forming fiber packed tower 104. And comprising.

  The electrodialysis apparatus 103 includes a room partitioned by an ion exchange membrane. The ion exchange membrane includes a cation membrane that selectively transmits only cations and an anion membrane that selectively transmits only anions. They are assembled alternately. In the present invention, sodium ions, chlorine ions, and the like are desalted as much as possible from seawater passing through the electrodialyzer 103, so that useful minerals such as potassium, calcium, and magnesium remain as much as possible without desalting. preferable. However, there is no cation membrane that does not allow permeation of desired metal ions such as potassium, calcium, magnesium and the like. Therefore, a monovalent ion selective membrane is used as the cation membrane. As a result, monovalent ions such as sodium, potassium, and chlorine ions are selectively removed from seawater and the like, and most of the ions existing in the raw water remain without removing divalent or higher ions.

  As such a monovalent ion selective membrane used in the electrodialyzer 103, for example, product number k-192 manufactured by Astom Co., Ltd. can be mentioned. Moreover, as an anion exchange membrane (anion membrane), arbitrary things can be used, For example, product number A-501 by Astom Co., Ltd. can be mentioned.

  When performing treatment with such a water treatment apparatus, the treated water 101 is introduced into the pretreatment apparatus 102 as necessary and subjected to microfiltration, and filtered water 106 from which suspended substances are sufficiently removed is obtained. obtain. The filtered water 106 is supplied to the electrodialyzer 103 to allow the dissolved monovalent ions in the filtered water 106 to pass through the ion exchange membrane, and the water in which these monovalent ions are reduced is removed from the monovalent ionized water 107. Water obtained by concentrating monovalent ions is obtained as concentrated water 109.

  This demonovalent ionized water 107 is further introduced into the chelate-forming fiber packed tower 104 and passed through the chelate-forming fiber bed 105 to form a chelate with boron remaining in the demonovalent ionized water 107. To obtain the mineral-containing water 108.

  The electrodialyzer 103 can appropriately adjust the desalting utilization rate (concentration ratio) to adjust the mineral content in the demonovalent ionized water 107 as desired.

  Further, the chelate-forming fiber can be used even when other metal ions such as metals such as Mg, Ca, Zn, Na, and K, or other anions such as halogen ions such as fluorine, chlorine, and iodine coexist. It has the property of selectively forming a chelate with a metal component. Therefore, by forming a chelate with boron remaining in the demonovalent ionized water 107, the boron can be removed and the mineral-containing water 108 can be obtained without reducing the mineral content.

  The mineral-containing water 108 thus obtained contains abundant metal ions and the like that are divalent or higher although monovalent ions are reduced. Mineral-containing water 108 also contains almost no boron, and the boron content is 1.0 mg / l or less of Japanese tap water quality standard requirements, and the provisional value 0.5 mg in the WHO drinking water quality guidelines. / L or less, and still well below the water quality standard of 0.3 mg / l or less in Korea, or below the detection limit, and is a mineral-containing water suitable for drinking.

  When producing mineral-containing water from seawater according to this embodiment, the target value of boron in the mineral-containing water 108 is set to 0.1 mg / l or less, for example, and the boron concentration in the mineral-containing water 108 is continuously set. Detecting and replacing the chelating fiber bed when the boron concentration in the mineral-containing water 108 exceeds 0.1 mg / l.

  A modification of the second embodiment of the present invention is shown in FIG. When the treatment is performed according to this deformation, the treated water 201 is introduced into the pretreatment device 202 as necessary and subjected to microfiltration to obtain filtered water 206 from which suspended substances are sufficiently removed. This filtered water 206 is introduced into the chelate-forming fiber packed tower 204, and passed through the chelate-forming fiber bed 205 to form a chelate with boron in the water to remove boron. Water 207 having a reduced boron content exiting the chelate-forming fiber packed tower 204 is supplied to the electrodialyzer 203, and dissolved monovalent ions in the water 207 are allowed to permeate through the ion exchange membrane, and these monovalents. Water in which ions are reduced is obtained as mineral-containing water 208, and water in which monovalent ions are concentrated is obtained as concentrated water 209.

  The mineral-containing water 208 thus obtained contains abundant metal ions and the like containing divalent or higher valent ions, but contains almost no boron. About the boron content, The water quality standard requirement for tap water is 1.0 mg / l or less, and it is well below the provisional value of 0.5 mg / l in the WHO drinking water quality guidelines, and still well below the water quality standard of 0.3 mg / l in Korea, or Below the detection limit. In the concentrated water 209, monovalent ions such as sodium chloride are concentrated and contained, and boron is hardly contained. Thus, the concentrated water 209 can be effectively used in the food and fishery fields without further deboronation treatment.

  Drinkable water and mineral-containing water obtained from seawater according to the method of the present invention both meet the global boron water quality standards. From this, when mixing the water suitable for drinking with mineral containing water and manufacturing the water from which the density | concentration of a mineral content differs, it can mix | blend in a free ratio, without minding the water quality standard of boron.

  Furthermore, when seawater treatment is performed according to the present invention, the seawater is passed through a chelate-forming fiber packed tower, and the water exiting the chelate-forming fiber packed tower is free of boron, but chlorine ions, EDTA hardness, sulfate ions Etc. are not reduced, and no significant fluctuation is observed before and after the chelate-forming fiber packed tower. From this, it is safe to remove boron from products that have been made from seawater as raw materials, such as salt and bittern, when the water from the chelate-forming fiber packed tower is used as raw materials. .

  Next, examples of the present invention will be shown. However, the present invention is not limited by the following examples as a matter of course, and it is of course possible to implement the invention with appropriate modifications within a range that can be adapted to the gist of the preceding and following descriptions. These are all included in the technical scope of the present invention.

Example 1
Seawater desalination treatment was performed using a water treatment apparatus as shown in FIG. As the treated water 1, offshore Miura offshore water was passed through 500 L / h. As the chelate-forming fiber bed 5, 15 kg (solid content) of Kirest fiber GRY-LW obtained from Kirest Co., Ltd. was packed into a cylinder (diameter 30 cm × height 105 cm) as the chelate-forming fiber packed tower 4. The space velocity (SV) was 10 h- ¹ .

  The obtained results are shown in Table 1.

Example 2
Mineral-containing water was produced using a water treatment apparatus as shown in FIG. In the electrodialysis apparatus 103, k-192 manufactured by Astom Co., Ltd., which is a monovalent ion selective membrane as a cation membrane (cation membrane), and Astom Co., Ltd. manufactured as an anion exchange membrane (anion membrane). A-501 was used. As the treated water 11, offshore Miura offshore water was passed through 500 L / h. As the chelate-forming fiber bed 15, 15 kg (solid content) of the Kirest fiber GRY-LW obtained from Kirest Co., Ltd. was packed into a cylinder (diameter 30 cm × height 105 cm) as the chelate-forming fiber packed tower 14. The space velocity (SV) was 10 h- ¹ .

  The obtained results are shown in Table 2.

  In the table, sodium was analyzed according to Ministry of Health, Labor and Welfare Notification No. 261, sulfate ion was analyzed according to the ion chromatography method, and the others were analyzed according to Ministry of Health, Labor and Welfare Notification No. 370. Boron was analyzed according to the ICP method. Organic substances in seawater (potassium permanganate consumption) were not measurable because they contained a lot of chloride ions. The taste of seawater was not drinkable.

  As can be seen from Table 1, since the treatment amount was 91.4 tons and the boron concentration in the treated water exceeded 0.1 mg / l, the operation was stopped.

  Table 2 shows that monovalent ions such as sodium, potassium and chlorine ions are removed from the desalted water, but divalent ions such as magnesium and calcium remain at substantially the same concentration as the raw water. In addition, chelate-forming fibers can be used in the presence of other metal ions such as metals such as Mg, Ca, Zn, Na, and K, or other anions such as halogen ions such as fluorine, chlorine, and iodine. It turns out that it has the characteristic of forming a chelate selectively with an acid.

Example 3
Using the apparatus shown in FIG. 2, Miura-oki offshore deep water was passed as treated water 1 at 17 mL / min. As the chelate-forming fiber bed 15, 56.5 mL of a cylinder (inner diameter 2.5 cm × height 11.5 cm) as a chelate-forming fiber packed tower 14 was filled with 15 g (solid content) of chilled fiber GRY-LW. The space velocity (SV) was 18.1 h ⁻¹ .

The properties of deep sea water were as follows:
Boron concentration: 4.4 mg / L (ICP emission spectroscopic analysis)
EDTA hardness: 6400 mg CaCO ₃ / L (EDTA titration)
Chlorine ion concentration: 19000 mg / L (ion chromatography)
Sulfate ion concentration: 2400 mg / L (ion chromatography)

Properties of the water 17 exiting the chelate-forming fiber packed tower 14 are as shown in FIGS.
5-7, when deep sea water is processed through the chelate-forming fiber packed tower 14, the boron concentration is below the lower limit of quantification (0.01 mg / L) up to a bed volume of about 200, and the chelate-forming fiber. It can be seen that the boron in the deep ocean water is removed well. Further, chlorine ions, EDTA hardness, sulfate ions, etc. are not reduced, and no significant fluctuation is observed before and after the chelate-forming fiber packed tower 14.

  Accordingly, the water exiting the chelate-forming fiber packed tower 14 is safe because the boron is removed. Therefore, for products that have been made from seawater as raw materials, such as salt and bitterns, when boron is used as the raw material from the water 17 exiting the chelate-forming fiber packed tower 14, boron is removed and is safe. is there.

  Further, since the boron concentration in the water exiting the chelate-forming fiber packed tower 14 is reduced, it can be seen that boron is also removed from the non-permeated water 19 that does not permeate the RO membrane separation device 13.

  The same as described above can be applied to the apparatus shown in FIG. 4, and the water exiting the chelate-forming fiber packed tower 204 has a reduced boron concentration, and therefore, from the concentrated water 209 of the electrodialyzer 203. It can also be seen that boron is removed.

  The method for producing water suitable for drinking by reducing the boron content in the water of the present invention generally reduces the boron content in water such as seawater and brackish water desalination, purified (up) water treatment, etc. Can be used for In addition, the method for producing mineral-containing water suitable for drinking by reducing the boron content of the present invention includes foods such as health foods, biotechnology, pharmaceuticals and cosmetics such as additives, and agricultural fields such as cultivation liquid and soil improvement. Can be used as a raw material in a wide range of fields. The non-permeated water produced as a by-product in the method of the present invention is not further subjected to deboronation treatment, and is effective in the field of food such as fermentation accelerators, salt-making, confectionery, etc. Can be used. In addition, the concentrated water produced as a by-product in the method of the present invention can be effectively used in food products such as salt production, confectionery and meat processing, and in the marine products field such as fish processing without further deboronation treatment. Conventionally, products made from seawater as raw materials, such as salt and bittern, are safe because boron is removed when the water from the chelate-forming fiber packed tower is used as a raw material.

The schematic whole structure of the water treatment apparatus which enforces the water treatment method of 1st embodiment of this invention is shown. The schematic whole structure of the water treatment apparatus which implements the modified water treatment method of 1st embodiment of this invention is shown. The schematic whole structure of the water treatment apparatus which enforces the water treatment method of 2nd embodiment of this invention is shown. The schematic whole structure of the water treatment apparatus which implements the modified water treatment method of 2nd embodiment of this invention is shown. In FIG. 2 or FIG. 4, the properties of water exiting the packed tower 14 or 204, respectively, are shown. In FIG. 2 or FIG. 4, the properties of water exiting the packed tower 14 or 204, respectively, are shown. In FIG. 2 or FIG. 4, the properties of water exiting packed tower 14 or 204, respectively, are shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water to be treated 3 RO membrane separation device 4 Packing tower 5 Chelate-forming fiber bed 7 Permeated water 8 Treated water 9 Non-permeated water 11 Water to be treated 13 RO membrane separator 14 Packing tower 15 Chelate-forming fiber bed 18 Permeated water 19 Non-permeated water 101 Water to be treated 103 Electrodialyzer 104 Packing tower 105 Chelate-forming fiber bed 108 Mineral-containing water 109 Concentrated water 201 Water to be treated 203 Electrodialyzer 204 Packed tower 205 Chelate-forming fiber bed 208 Mineral-containing water 209 Concentration water

Claims (12)

  The boron-containing water is passed through a reverse osmosis membrane separation device, the water that has permeated the membrane and exited the device is then passed through a device filled with chelating fibers that have chelating ability to boron and its compounds, and the membrane A method for producing water suitable for drinking by reducing the boron content remaining in permeated water.   Boron-containing water is passed through a device filled with chelating fibers that have chelating ability for boron and its compounds to reduce the boron content, and then passed through a reverse osmosis membrane separator to produce a solute that permeates the membrane. A method for producing removed drinking water and non-permeated water in which a solute is concentrated without passing through a membrane.   Boron-containing water is passed through an electrodialyzer, and demonovalent ionized water from which monovalent ions have been removed is then passed through a device filled with chelate-forming fibers having excellent chelate-forming ability for boron and its compounds. A method for producing mineral-containing water suitable for drinking by reducing the boron content remaining in demonovalent ionized water.   Drinking with boron-containing water passed through a device filled with chelating fibers that have chelating ability to boron and its compounds to reduce boron content and then passed through an electrodialyzer to remove monovalent ions A method for producing mineral-containing water suitable for water and monovalent ion-enriched water enriched with monovalent ions.   The method according to any one of claims 1 to 4, wherein the chelate-forming fiber has a chelate functional group bonded to the fiber by a chemical reaction.   The method according to claim 3 or 4, wherein the electrodialyzer uses a monovalent ion selective membrane as a cation membrane.   The method according to any one of claims 1 to 6, wherein the boron-containing water is seawater or brine.   8. The method according to any one of claims 1, 2, 5, and 7, wherein the water suitable for drinking has a boron content of 1.0 mg / l or less and contains almost no minerals.   The method according to any one of claims 3 to 7, wherein the mineral-containing water suitable for drinking has a boron content of 1.0 mg / l or less and monovalent ions are selectively reduced.   The method according to claim 8 or 9, wherein the boron content is 0.5 mg / l or less.   The method according to claim 10, wherein the boron content is 0.3 mg / l or less.   The chelate-forming fiber has a group having an amino group and at least two hydroxyl groups bonded to carbon in the molecule of the fiber, and has chelate-forming ability for boron and its compounds. The method according to claim 1, wherein the method is one.

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