Column-type water treatment apparatus and water treatment method

Abstract

To provide a column-type water treatment apparatus that exhibits excellent water permeability and resistance to decrease in adsorption performance.SOLUTION: A column-type water treatment apparatus 101 comprises: a column 10 equipped with an inlet 11 for introducing untreated water W1 and an outlet 12 for discharging treated water W2, which is the result of treating the untreated water W1; and a treatment layer 20 accommodated inside the column 10, the treatment layer comprising non-granular ion-exchange inorganic particles and a holding aid for holding the ion-exchange inorganic particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a column-type water treatment device and a water treatment method. [Background technology]

[0002] BACKGROUND ART Conventionally, a technique has been known in which an adsorbent having ion exchange capacity is used as a water treatment agent.

[0003] For example, Patent Document 1 discloses a water treatment method comprising the steps of adding ion exchanger powder to water to be treated that contains harmful ions, causing the harmful ions to be adsorbed onto the ion exchanger powder, separating the ion exchanger powder from the water to be treated, and treating the separated ion exchanger powder with a chemical solution to regenerate it.

[0004] Patent Document 2 discloses a water treatment device equipped with an adsorption vessel or adsorption tower filled with a strontium adsorbent obtained by granulating and firing a mixture of alkali metal titanate powder, clay, polymeric alcohol, and water. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-066161 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-042395 Summary of the Invention [Problem to be solved by the invention]

[0006] Batch-type water treatment is a technology in which an adsorbent is added to the water to be treated, the adsorbent adsorbs the substances to be removed, and the adsorbed adsorbent is then filtered. Water treatment equipment for batch-type water treatment often requires a large-scale solid-liquid separation device such as a centrifugal separator. Therefore, it is difficult to miniaturize water treatment equipment for batch-type water treatment, and the cost is high.

[0007] A known technology involves placing an adsorbent in a container and passing the water to be treated through the container. This technology allows for the miniaturization of water treatment devices. However, if the particle size of the adsorbent placed in the container is small, the water resistance of the water to be treated passing through the container increases, which tends to reduce the water permeability. In order to improve the water permeability of the water to be treated, a high-pressure pump may be used to pass the water to be treated. When using a high-pressure pump to pass the water to be treated, a pressure-resistant container is often used to house the adsorbent, which increases the cost of the water treatment device. Furthermore, if the particle size of the adsorbent is small, the adsorbent is likely to flow out when the water to be treated is discharged.

[0008] On the other hand, it is known to use an adsorbent obtained by granulation (sometimes referred to as a granulated adsorbent) as the adsorbent to be contained in a container. When a granulated adsorbent is contained in a container for water treatment, a general-purpose container can be used as the container for containing the granulated adsorbent. However, the manufacturing cost of granulated adsorbents is high. In addition, the adsorption performance of granulated adsorbents is easily reduced. Furthermore, granulated adsorbents have low mechanical strength.

[0009] On the other hand, there is also a method in which an adsorbent is mixed with chemical fibers or the like and molded into a cartridge shape, and the molded product is placed in a container for water treatment. However, molded products containing adsorbents have low adsorption performance per unit volume, and it may be difficult for them to exhibit sufficient adsorption performance.

[0010] As described above, conventional water treatment devices using adsorbents have been large-scale devices, or even if the water treatment device can be made smaller, depending on the form of the adsorbent contained in the container, the water permeability and adsorption performance may be low. For this reason, further improvements in water treatment technology have been required.

[0011] An object of the present invention is to provide a column-type water treatment device that has good water permeability and is prevented from decreasing in adsorption performance, and a water treatment method using the column-type water treatment device. [Means for solving the problem]

[0012] The inventors discovered that by providing a treatment layer in a column in which non-granulated ion-exchange inorganic particles as an adsorbent and a retention aid that holds the ion-exchange inorganic particles coexist, excellent water permeability can be achieved when the water to be treated is passed through the column, and the decline in adsorption performance is suppressed compared to the adsorption performance when only non-granulated ion-exchange inorganic particles are used in the treatment layer, and this led to the completion of the present invention.

[0013] The present invention includes the following aspects.

[0014] [1] A column-type water treatment device, a column provided with an inlet for introducing water to be treated and an outlet for discharging treated water obtained by treating the water to be treated; a treatment layer accommodated inside the column and containing non-granulated ion-exchange inorganic particles and a retention aid for retaining the ion-exchange inorganic particles; Equipped with Column-type water treatment equipment.

[0015] [2] In the column-type water treatment device according to [1], The treatment layer includes a mixed layer of the ion exchange inorganic particles and the retention aid. Column-type water treatment equipment.

[0016] [3] [2] The column-type water treatment device according to the present invention, the mixing ratio of the ion-exchange inorganic particles to the retention aid contained in the mixed layer (the ion-exchange inorganic particles:the retention aid) is in the range of 1:9 to 9:1 by mass ratio; Column-type water treatment equipment.

[0017] [4] In the column-type water treatment device according to [1], The treatment layer has a structure of at least two layers, the treatment layer includes a layer containing the ion-exchange inorganic particles; Column-type water treatment equipment.

[0018] [5] In the column-type water treatment device according to [1], The treatment layer has a structure of at least two layers, The treatment layer includes a layer consisting only of the retention aid. Column-type water treatment equipment.

[0019] [6] In the column-type water treatment device according to [1], The treatment layer has a structure of at least two layers, a layer consisting only of the ion-exchange inorganic particles is disposed on a side of the treatment layer closer to the introduction section, a layer consisting of only the retention aid is disposed in the treatment layer on a side closer to the discharge section than the ion-exchange inorganic particles; Column-type water treatment equipment.

[0020] [7] In the column-type water treatment device according to [1], The treatment layer has a structure of at least two layers, The mixed layer is disposed on a side of the treatment layer closer to the introduction section, A layer consisting only of the retention aid is arranged on the treatment layer closer to the discharge section than the mixed layer. Column-type water treatment equipment.

[0021] [8] [1] to [7], the column-type water treatment device according to any one of [1] to [7], The retention aid is a porous particle. Column-type water treatment equipment.

[0022] [9] [1] to [8], the column-type water treatment device according to any one of [1] to [8], The retention aid is diatomaceous earth. Column-type water treatment equipment.

[0023]

[10] [1] to [9], the column-type water treatment device according to any one of [1] to [9], The particle size of the retention aid is larger than the particle size of the ion-exchange inorganic particles. Column-type water treatment equipment.

[0024]

[11] A water treatment method for treating the water to be treated using the column-type water treatment device according to any one of [1] to

[10] , introducing the water to be treated from the introduction portion; a step of passing the water to be treated introduced from the introduction part through the treatment layer and treating the water to be treated to produce the treated water; Discharging the treated water from the discharge section; have Water treatment methods. [Effects of the Invention]

[0025] According to one aspect of the present invention, it is possible to provide a column-type water treatment device that has good water permeability and is prevented from decreasing in adsorption performance, and a water treatment method using the column-type water treatment device. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of a column-type water treatment device according to an embodiment of the present invention. [Figure 2] FIG. 4 is a schematic cross-sectional view illustrating another example of a column-type water treatment device according to the present embodiment. [Figure 3] FIG. 4 is a schematic cross-sectional view illustrating another example of a column-type water treatment device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] [Column-type water treatment device and water treatment method] One aspect of the present invention is a column-type water treatment device. The column-type water treatment device according to one aspect of the present invention includes a column having an inlet for introducing water to be treated and an outlet for discharging treated water obtained by treating the water to be treated, and a treatment layer accommodated inside the column and containing non-granulated ion-exchange inorganic particles (hereinafter sometimes simply referred to as ion-exchange inorganic particles) and a retention aid for retaining the ion-exchange inorganic particles.

[0028] One aspect of the present invention is a water treatment method. The water treatment method according to one aspect of the present invention is a method for treating water to be treated using a column-type water treatment device according to one aspect of the present invention. The water treatment method includes a step of introducing the water to be treated from an introduction section, a step of passing the water to be treated introduced from the introduction section through a treatment layer to treat the water to produce treated water, and a step of discharging the treated water from a discharge section.

[0029] In the column-type water treatment device and water treatment method according to one embodiment of the present invention, the treatment layer preferably includes a mixed layer of ion-exchange inorganic particles and a retention aid. The treatment layer may have a single layer structure or at least two layers. When the treatment layer has a laminated structure of two or more layers, it also preferably includes a layer containing ion-exchange inorganic particles. When the treatment layer has a laminated structure of two or more layers, it also preferably includes a mixed layer of ion-exchange inorganic particles and a retention aid. When the treatment layer has a laminated structure of two or more layers, it also preferably includes a layer consisting of only ion-exchange inorganic particles. When the treatment layer has a laminated structure of two or more layers, it also preferably includes a layer consisting of only a retention aid. When the treatment layer has a laminated structure of two or more layers, it is also preferable for the treatment layer to include a combination of these. When the treatment layer includes a layer consisting of only a retention aid, it is also preferable for the layer consisting of only a retention aid to be positioned at least closest to the discharge section.

[0030] A column-type water treatment device and a water treatment method according to one embodiment of the present invention can be applied to devices and methods for treating various types of water to be treated, such as tap water, groundwater, hot spring water, swamp water, seawater, river water, various types of industrial wastewater, mine wastewater, and power plant wastewater. Furthermore, according to the column-type water treatment device and water treatment method according to one aspect of the present invention, the water treatment device is low in cost, excellent water permeability is obtained, and a decrease in adsorption performance is suppressed.

[0031] An example of a preferred embodiment of the present invention will be described below, but the present invention is not limited to the content of the embodiment.

[0032] First Embodiment A first embodiment of the present invention will be described below with reference to the drawings. Note that in the drawings, some parts are shown enlarged or reduced in size for ease of explanation.

[0033] FIG. 1 is a schematic cross-sectional view illustrating an example of a column-type water treatment device according to this embodiment. As shown in FIG. 1, the column-type water treatment device 101 includes a column 10. The column 10 includes an inlet 11 for introducing water W1 to be treated and an outlet 12 for discharging treated water W2 obtained after the water W1 has been treated. The column 10 is made of, for example, at least one material selected from the group consisting of metal, resin, and fiber-reinforced resin. In the column-type water treatment device 101, the cross-section of the column 10 cut perpendicular to the direction of gravity is circular. The cross-section of the column 10 cut perpendicular to the direction of gravity is not particularly limited as long as the cross-section allows good water permeability of the water W1 to be treated and enables water treatment with reduced degradation of adsorption performance. The cross-sectional shape may be triangular, rectangular, or a polygon with pentagons or more sides.

[0034] The column 10 contains ion-exchange inorganic particles and a retention aid that retains the ion-exchange inorganic particles, and a treatment layer 20 containing the ion-exchange inorganic particles and the retention aid is provided. The amounts of the ion-exchange inorganic particles and the retention aid constituting the treatment layer 20 are not particularly limited as long as they are sufficient to adsorb the components to be removed from the water to be treated W1 and provide good water permeability for the water to be treated W1. In the column-type water treatment device 101, the treatment layer 20 is a single-layer treatment layer 20A composed of a single layer. The single-layer treatment layer 20A is a mixed layer containing ion-exchange inorganic particles and a retention aid. The mixing ratio of the ion-exchange inorganic particles to the retention aid (ion-exchange inorganic particles:retention aid) contained in the single-layer treatment layer 20A (i.e., the mixed layer) is preferably in the range of 1:9 to 9:1 by mass ratio. In order to ensure good water permeability of the treated water W1 and to help prevent a decrease in adsorption performance, the mixing ratio of the ion-exchange inorganic particles to the retention aid (ion-exchange inorganic particles:retention aid) is more preferably in the range of 3:7 to 7:3 by mass, and even more preferably in the range of 4:6 to 6:4.

[0035] From the viewpoint of improving the permeability of the water to be treated, it is preferable that the particle size of the retention aid is larger than that of the ion-exchange inorganic particles, with regard to the relationship between the particle sizes of the ion-exchange inorganic particles and the retention aid.

[0036] The ratio of the particle diameter of the retention aid to the particle diameter of the ion-exchange inorganic particles (particle diameter of retention aid / particle diameter of ion-exchange inorganic particles) is, for example, preferably 1.1 or more, more preferably 3 or more, even more preferably 5 or more, and even more preferably 10 or more. When the ratio of the particle diameter of the retention aid to the particle diameter of the ion-exchange inorganic particles is 1.1 or more, the ability to retain the ion-exchange inorganic particles is likely to be improved while suppressing an increase in water flow resistance. The upper limit of this ratio is not particularly limited as long as it can be accommodated within the column 10. The upper limit of the ratio of the particle diameter of the retention aid to the particle diameter of the ion-exchange inorganic particles is, for example, 100 or less. When the ratio of the particle diameter of the retention aid to the particle diameter of the ion-exchange inorganic particles is, for example, 100 or less, the water flow resistance is likely to be reduced while suppressing a decrease in the ability to retain the ion-exchange inorganic particles.

[0037] The particle size of the ion-exchanged inorganic particles is not particularly limited and may be, for example, 0.01 μm or more, or 0.1 μm or more. The particle size of the ion-exchanged inorganic particles is not particularly limited and may be, for example, 10 μm or less, or 1 μm or less. The particle sizes of the ion-exchanged inorganic particles and retention aid can be measured as the median size (D50) by laser diffraction / scattering using, for example, a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3300, manufactured by Microtrac Bell Co., Ltd.). In this specification, the median size refers to the median value of the particle size distribution measured on a particle volume basis. In the examples described below, the particle sizes of the ion-exchanged inorganic particles and retention aid can be measured using the same method as above.

[0038] In this specification, the term "particles" is a concept that includes both powder and granular particles having a particle size larger than that of powder. Furthermore, in this specification, the shape of the particles is not limited to spherical, and may be various shapes.

[0039] The ion-exchange inorganic particles are not particularly limited as long as they are inorganic particles with ion exchange capacity. The ion-exchange inorganic particles may be selected depending on the components to be removed from the water to be treated W1. The ion-exchange inorganic particles may be either amorphous or crystalline. From the viewpoint of easily suppressing a decrease in adsorption performance, the ion-exchange inorganic particles are preferably ion-exchange inorganic crystals. Examples of ion-exchange inorganic particles include sodium titanate, layered phosphates (e.g., zirconium phosphate), and clay minerals (e.g., layered silicates and layered double hydroxides). Among these, if there is a concern that the water to be treated W1 contains heavy metals as components to be removed, the ion-exchange inorganic particles preferably contain sodium titanate, and even more preferably sodium titanate. The sodium titanate is preferably sodium titanate whose main phase is represented by Na2Ti3O7 (hereinafter, sometimes referred to as sodium trititanate). Note that sodium titanate whose main phase is represented by Na2Ti3O7 represents that the proportion of sodium titanate represented by Na2Ti3O7 is the highest among the phases constituting sodium titanate.

[0040] When the ion-exchange inorganic particles are sodium trititanate, sodium trititanate can be obtained, for example, by dry-mixing a titanium compound (e.g., titanium dioxide, etc.), a sodium salt of an organic acid (e.g., sodium acetate, trisodium citrate, sodium oxalate, sodium tartrate, etc.), and, if necessary, sodium carbonate, followed by calcination. Sodium trititanate can also be obtained, for example, by dry-mixing a titanium compound (e.g., titanium dioxide, etc.), sodium carbonate, and sodium nitrate flux, followed by calcination. Furthermore, sodium trititanate can also be obtained by wet-mixing a titanium compound (e.g., titanium dioxide, etc.) with sodium carbonate, spray-drying the mixture to produce a dried product, and then calcining the resulting dried product. Crystals of sodium trititanate obtained by the above-described method or the like may be used as they are. In this case, the particle size may be adjusted by adjusting the production conditions of sodium trititanate. Sodium trititanate crystals obtained by the above-described method or the like may be pulverized to adjust the particle size before use. The ion-exchange inorganic particles to be used may be synthesized ion-exchange inorganic particles or commercially available products.

[0041] The retention aid is not particularly limited as long as it can retain the ion-exchange inorganic particles. The retention aid may be porous particles or non-porous particles. From the viewpoint of improving the water permeability of the water to be treated W1, the retention aid is preferably porous particles. If the retention aid is porous particles, the voids in the treatment layer 20 are more likely to increase, thereby improving the water permeability of the water to be treated W1. The retention aid is not particularly limited, and examples include porous inorganic particles such as diatomaceous earth, perlite, and vermiculite, as well as porous organic particles such as cellulose, and can be selected depending on the desired water permeability. Among these, from the viewpoint of improving the water permeability of the water to be treated W1, the retention aid is preferably porous inorganic particles, more preferably at least one selected from diatomaceous earth and perlite, and even more preferably diatomaceous earth.

[0042] In the column-type water treatment device 101, the treatment layer 20 is preferably configured to be replaceable. If the treatment layer 20 is configured to be replaceable, it is preferable because the treatment layer 20 can be regenerated and reused.

[0043] The column-type water treatment device 101 includes a filter 30 inside the column 10 that supports the treatment layer 20. The filter 30 is a component that is provided as needed. From the viewpoint of making it easier to suppress the outflow of the non-granulated ion-exchange inorganic particles and retention aid contained in the treatment layer 20, the column-type water treatment device 101 preferably includes the filter 30 inside. The filter 30 is not particularly limited as long as it can support the treatment layer 20 and can obtain good water permeability for the water to be treated W1. Examples of the filter 30 include filter paper, filter cloth (filter cloth), membrane filters, and glass filters.

[0044] In the column-type water treatment device 101, the inlet section 11 is configured to be detachable from the inlet-side pipe 40 through which the water to be treated W1 is fed, and the outlet section 12 is configured to be detachable from the outlet-side pipe 50 through which the treated water W2 is fed. If the column-type water treatment device 101 is configured to be detachable from the inlet-side pipe 40 and the outlet-side pipe 50, it is preferable because replacement of the column-type water treatment device 101 becomes easy.

[0045] (Water treatment method) Next, a description will be given of a water treatment method for treating water W1 to be treated using the column-type water treatment device 101. The water treatment method includes a step (step P1) of introducing water W1 to be treated from an introduction section 11, a step (step P2) of passing the water W1 to be treated introduced from the introduction section 11 through the treatment layer 20 to treat the water W1 to produce treated water W2, and a step (step P3) of discharging the treated water W2 from a discharge section 12.

[0046] Step P1 is a step of introducing the water to be treated W1, which is delivered from the introduction part-side conduit 40 connected to the introduction part 11 of the column 10, into the column 10 from the introduction part 11 of the column 10. The water to be treated W1 delivered from the introduction part-side conduit 40 may be delivered by a pump (not shown), or may be delivered by water pressure without using a pump. Examples of the water to be treated W1 include tap water, groundwater, hot spring water, swamp water, seawater, river water, various types of industrial wastewater, mine wastewater, and power plant wastewater.

[0047] In step P2, the water to be treated W1 introduced into the column 10 is treated by the treatment layer 20 to produce treated water W2. When the water to be treated W1 is introduced into the column 10, the water to be treated W1 reaches the treatment layer 20. When the water to be treated W1 reaches the treatment layer 20, the water to be treated W1 comes into contact with the treatment layer 20, and the components to be removed contained in the water to be treated W1 are adsorbed onto the ion-exchange inorganic particles contained in the treatment layer 20 and treated. The water to be treated W1 is then treated by passing through the treatment layer 20 and converted into treated water W2. In this embodiment, the treatment layer 20 is provided with a single-layer treatment layer 20A, which is a mixed layer containing ion-exchange inorganic particles and a retention aid. Therefore, the water to be treated W1 comes into contact with the single-layer treatment layer 20A and is treated, thereby being converted into treated water W2.

[0048] When the water to be treated W1 contains metal ions such as aluminum, cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc, these metal ions can be removed by including sodium trititanate as the ion exchange inorganic particles contained in the single-layer treatment bed 20A. For example, when the water to be treated W1 is wastewater containing heavy metals generated from a factory such as a plating factory, it is preferable to use sodium trititanate as the ion exchange inorganic particles contained in the single-layer treatment bed 20A, since this will enable the removal of metal ions contained in the wastewater containing heavy metals.

[0049] The retention aid contained in the single-layer treatment layer 20A may be either porous particles or non-porous particles. The use of porous particles as the retention aid is preferred because it facilitates obtaining excellent water permeability. The use of porous inorganic particles, particularly diatomaceous earth, as the retention aid tends to further improve water permeability.

[0050] Step P3 is a step of discharging the treated water W2 treated in step P2 from the discharge-side pipe 50 connected to the discharge section 12 of the column 10 to the outside of the column 10. The treated water W2 has had the components to be removed contained in the water to be treated W1 removed in step P2. The treated water W2 is treated in the single-layer treatment bed 20A and converted into, for example, deionized water or pure water. The treated water W2 can be discharged without using a pump.

[0051] (Operation and effect of the first embodiment) According to this embodiment, the following effects can be achieved. (1) If only ion-exchange inorganic particles are filled in the treatment layer 20, the ion-exchange inorganic particles will be packed closely together, resulting in high water flow resistance and reduced water permeability. In contrast, according to this embodiment, the single-layer treatment layer 20A constituting the treatment layer 20 is a mixed layer containing ion-exchange inorganic particles and a retention aid. The presence of a retention aid in the single-layer treatment layer 20A allows the ion-exchange inorganic particles to be retained while increasing the spacing between the inorganic particles. Therefore, even if the ion-exchange inorganic particles are non-granulated, the water permeability of the water to be treated W1 is improved. Furthermore, because the ion-exchange inorganic particles are non-granulated, an adsorption amount close to the maximum adsorption amount of the ion-exchange inorganic particles can be obtained, and a decrease in adsorption performance is suppressed. Therefore, according to this embodiment, water permeability is improved and a decrease in adsorption performance is suppressed. (2) By using porous particles as a retention aid, it is possible to reduce the resistance to water flow and maintain high water permeability, so good water permeability can be obtained even when non-granulated ion-exchange inorganic particles are filled without granulating the ion-exchange inorganic particles. (3) When the particle size of the retention aid is larger than the particle size of the ion-exchange inorganic particles, high water permeability can be maintained even when non-granulated ion-exchange inorganic particles are filled without granulating the ion-exchange inorganic particles, thereby achieving good water permeability. (4) The ion-exchange inorganic particles and the retention aid are contained in the column 10, which provides good water permeability and eliminates the need for a pressure-resistant container. This reduces the manufacturing cost of the water treatment device. Furthermore, the ion-exchange inorganic particles are non-granulated, which reduces the manufacturing cost of the ion-exchange inorganic particles.

[0052] Second Embodiment Next, an example of a column-type water treatment device according to this embodiment will be described with reference to Fig. 2. Fig. 2 shows a schematic cross-sectional view of a column-type water treatment device 102.

[0053] The column-type water treatment device according to the second embodiment differs from the first embodiment in that the treatment layer 20 has a two-layer laminate structure consisting of a first treatment layer 21 and a second treatment layer 22. In the following description, differences from the first embodiment will be mainly described, and overlapping descriptions will be omitted or simplified. The same components as those in the first embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted or simplified.

[0054] FIG. 2 is a schematic cross-sectional view illustrating an example of a column-type water treatment device according to the present embodiment. As shown in FIG. 2, the column-type water treatment device 102 includes a column 10 having an inlet 11 for introducing water W1 to be treated and an outlet 12 for discharging treated water W2 obtained after the water W1 has been treated. The column 10 contains ion-exchanged inorganic particles and a retention aid for retaining the ion-exchanged inorganic particles. A treatment layer 20 containing the ion-exchanged inorganic particles and the retention aid is provided. The treatment layer 20 has a two-layer structure including a first treatment layer 21 and a second treatment layer 22, and is stacked on top of the filter 30. In the treatment layer 20, the first treatment layer 21 is disposed closer to the inlet 11, and the second treatment layer 22 is disposed closer to the outlet 12 than the first treatment layer 21. In the treatment layer 20, the second treatment layer 22 and the first treatment layer 21 are stacked in this order from the outlet 12 toward the inlet 11. Specific examples of the ion-exchange inorganic particles and the retention aid are the same as those described in the first embodiment.Specific examples of the filter 30 are the same as those described in the first embodiment.

[0055] In the column-type water treatment device 102, the first treatment layer 21 is not a mixed layer containing ion-exchange inorganic particles and a retention aid, but is a layer consisting only of ion-exchange inorganic particles. The second treatment layer 22 is not a mixed layer containing ion-exchange inorganic particles and a retention aid, but is a layer consisting only of a retention aid. The ratio of the amount of ion-exchange inorganic particles contained in the first treatment layer 21 to the amount of retention aid contained in the second treatment layer 22 (ion-exchange inorganic particles:retention aid) is preferably in the range of 1:9 to 9:1 by mass. From the viewpoint of improving the water permeability of the water to be treated W1 and easily suppressing a decrease in adsorption performance, the ratio of the amount of ion-exchange inorganic particles contained in the first treatment layer 21 to the amount of retention aid contained in the second treatment layer 22 (ion-exchange inorganic particles:retention aid) is more preferably in the range of 1:9 to 5:5 by mass, and even more preferably in the range of 1:9 to 3:7.

[0056] The ratio of the thickness of the first treatment layer 21 to the thickness of the second treatment layer 22 (thickness of the first treatment layer 21:thickness of the second treatment layer 22) is preferably in the range of 1:9 to 9:1. From the viewpoint of improving the permeability of the water to be treated W1 and making it easier to suppress a decrease in adsorption performance, the ratio of the thickness of the first treatment layer 21 to the thickness of the second treatment layer 22 (thickness of the first treatment layer 21:thickness of the second treatment layer 22) is more preferably in the range of 1:9 to 4:6, and even more preferably in the range of 1:9 to 2:8.

[0057] The particle size of the retention aid contained in the second treatment layer 22 is preferably larger than the particle size of the ion-exchange inorganic particles contained in the first treatment layer 21. The preferred particle size ratio is preferably within the range described in the first embodiment.

[0058] (Water treatment method) Next, a water treatment method for treating water W1 to be treated using a column-type water treatment device 102 will be described. The water treatment method differs from the first embodiment in that step P2 described in the first embodiment is a step in which the water W1 to be treated introduced from the introduction section 11 is brought into contact with and passed through a treatment layer 20 having a layer (first treatment layer 21) consisting only of ion-exchange inorganic particles and a layer (second treatment layer 22) consisting only of a retention aid, and the water W1 to be treated is treated to produce treated water W2. Step P2 will be described below.

[0059] In step P2, the water to be treated W1 introduced into the column 10 is treated by the treatment tank 20, which has a first treatment tank 21 and a second treatment tank 22, to produce treated water W2. When the water to be treated W1 is introduced into the column 10, it first reaches the first treatment tank 21, which is a tank made only of ion-exchange inorganic particles. Upon contact with the first treatment tank 21, the water to be treated W1 is treated by adsorption of the target components contained in the water to be treated W1 onto the ion-exchange inorganic particles, the degradation of which is suppressed. After passing through the first treatment tank 21, the water to be treated W1 reaches the second treatment tank 22, which is a tank made only of a retention aid. After reaching the second treatment tank 22, the water to be treated W1 passes through the second treatment tank 22 without being affected by its water permeability. The water to be treated W1 is then treated by passing through the treatment tank 20, first through the first treatment tank 21 and then through the second treatment tank 22, and is converted into treated water W2. When the water to be treated W1 contains metal ions such as aluminum, cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc, these metal ions can be removed, as described in the first embodiment, by including sodium trititanate as the ion-exchange inorganic particles constituting the first treatment layer 21. Furthermore, the use of porous particles as the retention aid constituting the second treatment layer 22 tends to improve water permeability, and the use of porous inorganic particles, particularly diatomaceous earth, tends to further improve water permeability.

[0060] (Operation and effect of the second embodiment) According to this embodiment, the following effects can be achieved. (1) The treatment layer 20 has a two-layer structure composed of a first treatment layer 21, which is a layer made only of ion-exchange inorganic particles, and a second treatment layer 22, which is a layer made only of a retention aid. The second treatment layer 22, which is a layer made only of a retention aid, has a layer of retention aid superimposed thereon. By placing a layer made only of ion-exchange inorganic particles on top of the layer of retention aid superimposed thereon, the ion-exchange inorganic particles are more easily retained. Therefore, even if the ion-exchange inorganic particles are non-granulated, the water-permeability of the treated water W1 is improved. Furthermore, because the ion-exchange inorganic particles are non-granulated, an adsorption amount close to the maximum adsorption amount of the ion-exchange inorganic particles is obtained, and a decrease in adsorption performance is suppressed. Therefore, according to this embodiment, water permeability is improved and a decrease in adsorption performance is suppressed. (2) By using porous particles as the retention aid constituting the second treatment layer 22, it is possible to further reduce the water flow resistance and maintain high water permeability, so that good water permeability can be obtained even if the first treatment layer 21 is filled only with non-granulated ion-exchange inorganic particles. (3) If the particle diameter of the retention aid constituting the second treatment layer 22 is larger than the particle diameter of the ion-exchange inorganic particles, high water permeability can be maintained, and therefore good water permeability can be obtained even if the first treatment layer 21 is filled only with non-granulated ion-exchange inorganic particles. (4) The provision of the second treatment layer 22, which is a layer consisting only of a retention aid, suppresses the outflow of the non-granulated ion-exchange inorganic particles that constitute the first treatment layer 21. Furthermore, since the outflow of the non-granulated ion-exchange inorganic particles is suppressed, when a filter 30 is provided, clogging of the filter 30 is suppressed, thereby achieving good water permeability. (5) The first treatment layer 21, which is a layer consisting only of ion-exchange inorganic particles, is provided on the second treatment layer 22, which is a layer consisting only of a retention aid. This provides good water permeability, eliminating the need for a pressure-resistant container. This reduces the manufacturing cost of the water treatment device. Furthermore, because the ion-exchange inorganic particles are non-granulated, the manufacturing cost of the ion-exchange inorganic particles is also low.

[0061] Third Embodiment Next, an example of a column-type water treatment device according to this embodiment will be described with reference to Fig. 3. Fig. 3 shows a schematic cross-sectional view of a column-type water treatment device 103.

[0062] The column-type water treatment device according to the third embodiment differs from the first embodiment in that the treatment layer 20 has a two-layer laminate structure consisting of a first treatment layer 21A and a second treatment layer 22. The column-type water treatment device according to the third embodiment also differs from the second embodiment in that the first treatment layer 21A of the treatment layer 20 is a mixed layer containing ion-exchange inorganic particles and a retention aid. In the following description, differences from the first and second embodiments will be mainly described, and overlapping descriptions will be omitted or simplified. The same components as those in the first and second embodiments will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0063] FIG. 3 is a schematic cross-sectional view illustrating an example of a column-type water treatment device according to this embodiment. As shown in FIG. 3, the column-type water treatment device 103 includes a column 10 having an inlet 11 and an outlet 12. A treatment layer 20 is provided inside the column 10. The treatment layer 20 has a two-layer structure including a first treatment layer 21A and a second treatment layer 22, and is stacked on top of a filter 30. The treatment layer 20 includes the second treatment layer 22 and the first treatment layer 21A stacked in this order from the outlet 12 toward the inlet 11. Note that a specific example of the filter 30 is the same as the specific example described in the first embodiment.

[0064] In the column-type water treatment device 103, the first treatment layer 21A is a mixed layer containing ion-exchange inorganic particles and a retention aid. The second treatment layer 22 is not a mixed layer containing ion-exchange inorganic particles and a retention aid, but is a layer consisting only of a retention aid. The retention aid contained in the first treatment layer 21A and the retention aid contained in the second treatment layer 22 may be the same or different. From the viewpoint of manufacturing costs, it is preferable that the retention aid contained in the first treatment layer 21A and the retention aid contained in the second treatment layer 22 are the same retention aid. Specific examples of the ion-exchange inorganic particles and the retention aid are the same as those described in the first embodiment.

[0065] The mass ratio of the ion-exchange inorganic particles to the retention aid contained in the first treatment layer 21A (i.e., the mixed layer) (ion-exchange inorganic particles:retention aid) is preferably the same as the mixing ratio described in the first embodiment.

[0066] In the column-type water treatment device 103, the ratio of the thickness of the first treatment layer 21A to the thickness of the second treatment layer 22 (thickness of the first treatment layer 21A:thickness of the second treatment layer 22) is preferably in the range of 1:9 to 9:1. From the viewpoint of improving the permeability of the water to be treated W1 and making it easier to suppress a decrease in adsorption performance, the ratio of the thickness of the first treatment layer 21A to the thickness of the second treatment layer 22 (thickness of the first treatment layer 21A:thickness of the second treatment layer 22) is more preferably in the range of 2:8 to 6:4, and even more preferably in the range of 3:7 to 5:5.

[0067] The particle size of the retention aid contained in the first treatment layer 21A and the second treatment layer 22 is preferably larger than the particle size of the ion-exchanged inorganic particles contained in the first treatment layer 21A. The ratio of the particle size of the retention aid to the particle size of the ion-exchanged inorganic particles (particle size of retention aid / particle size of ion-exchanged inorganic particles) is preferably the same as that described in the first embodiment.

[0068] (Water treatment method) Next, a water treatment method for treating water W1 to be treated using a column-type water treatment device 103 will be described. The water treatment method differs from the first and second embodiments in that step P2 described in the first and second embodiments is a step in which the water W1 to be treated introduced from the introduction section 11 is brought into contact with and passed through a treatment layer 20 having a mixed layer of ion-exchange inorganic particles and a retention aid (first treatment layer 21A) and a layer consisting only of a retention aid (second treatment layer 22), and the water W1 to be treated is treated to produce treated water W2. Step P2 will be described below.

[0069] In step P2, the water to be treated W1 introduced into the column 10 is treated by the treatment tank 20, which has a first treatment tank 21A and a second treatment tank 22, to produce treated water W2. When the water to be treated W1 is introduced into the column 10, it first reaches the first treatment tank 21A, which is a mixed layer of ion-exchange inorganic particles and a retention aid. Upon reaching the first treatment tank 21A, the water to be treated W1 comes into contact with the first treatment tank 21A, whereby the components to be removed contained in the water to be treated W1 are adsorbed onto the ion-exchange inorganic particles without affecting water permeability and without reducing adsorption performance. The water to be treated W1 that has passed through the first treatment tank 21A reaches the second treatment tank 22, which is a layer composed only of a retention aid. The water to be treated W1 that has reached the second treatment tank 22 passes through the second treatment tank 22 without being affected by water permeability. The water to be treated W1 is treated by passing through the treatment tank 20, first through the first treatment tank 21A and then through the second treatment tank 22, and converted into treated water W2. If the water to be treated W1 contains metal ions, such as aluminum, cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc, the ion-exchange inorganic particles contained in the first treatment tank 21A can remove these metal ions. Furthermore, using porous particles as both the retention aid contained in the first treatment tank 21A and the retention aid constituting the second treatment tank 22 tends to improve water permeability. Using porous inorganic particles as both the retention aid contained in the first treatment tank 21A and the retention aid constituting the second treatment tank 22 tends to further improve water permeability. In particular, using diatomaceous earth as both the retention aid contained in the first treatment tank 21A and the retention aid constituting the second treatment tank 22 tends to further improve water permeability.

[0070] (Operation and effect of the third embodiment) According to this embodiment, the following effects can be achieved. (1) The treatment layer 20 has a two-layer structure composed of a first treatment layer 21A, which is a mixed layer containing ion-exchange inorganic particles and a retention aid, and a second treatment layer 22, which is a layer consisting only of a retention aid. In the first treatment layer 21A, which is a mixed layer, ion-exchange inorganic particles and a retention aid are mixed, and the retention aid can hold the ion-exchange inorganic particles while increasing the spacing between the inorganic particles. In the second treatment layer 22, which is a layer consisting only of a retention aid, a layer of retention aid is formed. Furthermore, a mixed layer is disposed on top of the layer of retention aid, which holds the ion-exchange inorganic particles while increasing the spacing between the ion-exchange inorganic particles. The synergistic effect of the two layers further improves the permeability of the treated water W1 without granulating the ion-exchange inorganic particles, even if the ion-exchange inorganic particles are non-granulated. Furthermore, because the ion-exchange inorganic particles are non-granulated, an adsorption amount close to the maximum adsorption amount of the ion-exchange inorganic particles can be achieved, suppressing a decrease in adsorption performance. Therefore, according to this embodiment, water permeability is good and the decrease in adsorption performance is suppressed. (2) By using porous particles as the retention aid constituting the second treatment layer 22 and as the retention aid contained in the first treatment layer 21A, it is possible to reduce the water flow resistance and maintain high water permeability, so that good water permeability can be obtained even when non-granulated ion-exchange inorganic particles are used in the first treatment layer 21A. (3) When the particle diameter of either the retention aid constituting the second treatment layer 22 or the retention aid contained in the first treatment layer 21A is larger than the particle diameter of the ion-exchange inorganic particles, high water permeability can be maintained, and good water permeability can be obtained even when non-granulated ion-exchange inorganic particles are used in the first treatment layer 21A. (4) In the treatment layer 20, the first treatment layer 21A, which is a mixed layer, is laminated on top of the second treatment layer 22, which is a layer consisting only of a retention aid. Therefore, even if the first treatment layer 21A is unable to retain all the ion-exchange inorganic particles and the ion-exchange inorganic particles flow out from the first treatment layer 21A to the second treatment layer 22, the second treatment layer 22 can capture the flowed-out ion-exchange inorganic particles. This also improves water permeability. Furthermore, when a filter 30 is provided, the second treatment layer 22 can suppress the flow-out of the ion-exchange inorganic particles, thereby suppressing clogging of the filter 30. This also improves water permeability. (5) The first treatment layer 21A, which is a mixed layer containing ion-exchange inorganic particles and a retention aid, is provided on the second treatment layer 22, which is a layer consisting only of a retention aid. This provides good water permeability, eliminating the need for a pressure-resistant container. This reduces the manufacturing cost of the water treatment device. Furthermore, because the ion-exchange inorganic particles are non-granulated, the manufacturing cost of the ion-exchange inorganic particles is also low.

[0071] [Modification of the embodiment] The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of achieving the object of the present invention.

[0072] For example, in the second and third embodiments, the treatment layer 20 has a two-layer structure consisting of a first treatment layer 21 or 21A containing ion-exchange inorganic particles and a second treatment layer 22 consisting only of a retention aid. The treatment layer 20 may have a three-layer or more structure. For example, in the second and third embodiments, when the treatment layer 20 has a three-layer or more structure, another treatment layer may be provided on the first treatment layer 21 or 21A. Specifically, in the second and third embodiments, the filter 30 may have a structure in which the second treatment layer 22, the first treatment layer 21 or 21A, and a third treatment layer consisting only of a retention aid are stacked in this order on top of the filter 30 from the discharge section 12 toward the introduction section 11. When the treatment layer 20 has a three-layer structure consisting of the second treatment layer 22, the first treatment layer 21 or 21A, and the third treatment layer, for example, separation of the ion-exchange inorganic particles and the retention aid is more easily suppressed.

[0073] In the second and third embodiments, when the treatment layer 20 is composed of at least two layers, at least one layer selected from the group consisting of the first treatment layer 21 and the first treatment layer 21A, which are layers containing ion-exchange inorganic particles, may be arranged closer to the introduction section 11, and the second treatment layer 22, which is a layer consisting only of a retention aid, may be arranged closer to the discharge section 12 than the first treatment layer 21 and the first treatment layer 21A. In the second embodiment, when the treatment layer 20 is composed of at least two layers and the first treatment layer 21, which is a layer containing ion-exchange inorganic particles, is located closer to the introduction section 11, the second treatment layer 22 may be located closer to the discharge section 12 than the first treatment layer 21. In the third embodiment, when the treatment layer 20 is composed of at least two layers and the first treatment layer 21A, which is a layer containing ion-exchange inorganic particles, is located closer to the introduction section 11, the second treatment layer 22 may be located closer to the discharge section 12 than the first treatment layer 21A. Furthermore, in the second and third embodiments, when the treatment layer 20 is composed of at least two layers, the first treatment layer 21 or the first treatment layer 21A, which is a layer containing ion-exchange inorganic particles, may be arranged closest to the introduction section 11, and the second treatment layer 22, which is a layer consisting only of a retention aid, may be arranged closest to the discharge section 12. [Example]

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0075] (Preparation of ion-exchanged inorganic crystals) Sodium trititanate was prepared as an ion-exchange inorganic crystal used as an adsorbent. First, 135 mmol of titanium dioxide and 90 mmol of sodium acetate were weighed and mixed to obtain a mixed powder. The resulting mixed powder was placed in a 30 mL alumina crucible with a lid. The mixture was heated from room temperature (20°C) at a rate of 5°C / min in an electric furnace, and then calcined at a calcination temperature of 600°C for 10 hours. After calcination, the mixture was allowed to cool in the furnace to obtain sodium trititanate powder with a particle size of 1 μm or less. In Table 2, sodium trititanate is represented as Na2Ti3O7.

[0076] (Preparing the retention aid) Diatomaceous earth (#600 manufactured by Chuo Silica Co., Ltd.) was prepared as a retention aid for retaining sodium trititanate as an ion-exchanged inorganic crystal. The particle diameter of the diatomaceous earth was 30 μm.

[0077] Example 1 A bioglass absorption tube (AS ONE Corporation, model number "KF-30") with a diameter of 3 cm and a height of 9.5 cm was prepared as a column. The bottom of this column was the discharge side, and the top of this column was the introduction side. First, a quantitative filter paper (ADVANTEC No. 5C) was placed at the bottom of the column as a filter. Next, 5 parts by mass of diatomaceous earth was weighed out as a retention aid to be filled into the second treatment layer. The weighed diatomaceous earth was poured onto the filter paper to fill the diatomaceous earth and form a layer consisting only of diatomaceous earth. Next, 1 part by mass of diatomaceous earth and the sodium trititanate prepared above were weighed out and mixed to obtain a mixture. In the obtained mixture, the mixture ratio of sodium trititanate to diatomaceous earth (sodium trititanate:diatomaceous earth) was 1:1 by mass. The obtained mixture was filled on top of the layer consisting only of diatomaceous earth. In this manner, a two-layer structure treatment layer was provided inside the column, in which a second treatment layer consisting of only diatomaceous earth and a first treatment layer consisting of a mixture of sodium trititanate and diatomaceous earth were stacked in this order from the bottom to the top of the column. In this manner, the column-type water treatment device of Example 1 was fabricated.

[0078] <Example 2> The column-type water treatment device of Example 2 was prepared in the same manner as Example 1, except that the first treatment layer, which was a mixed layer of sodium trititanate and diatomaceous earth as ion-exchange inorganic particles, was changed to a first treatment layer consisting only of sodium trititanate by weighing out 1 part by mass of the sodium trititanate prepared above and filling it on top of a layer consisting only of diatomaceous earth.

[0079] Example 3 A column-type water treatment device of Example 3 was produced in the same manner as in Example 1, except that the second treatment layer, which was a layer made only of diatomaceous earth, was not provided.

[0080] <Examples 4 and 5> The column-type water treatment devices of each example were prepared in the same manner as in Example 1, except that in the first treatment layer, which is a mixed layer of sodium trititanate and diatomaceous earth as ion-exchange inorganic particles, the mixing ratio of sodium trititanate and diatomaceous earth (sodium trititanate:diatomaceous earth (mass ratio)) was changed according to Table 1.

[0081] Example 6 The column-type water treatment device of Example 6 was prepared in the same manner as Example 1, except that perlite ("Topco No. 34", manufactured by Showa Chemical Industry Co., Ltd., particle size 27.6 μm) was used instead of diatomaceous earth in both the second treatment layer, which was a layer consisting only of diatomaceous earth, and the first treatment layer, which was a mixed layer of a mixture of sodium trititanate and diatomaceous earth.

[0082] Example 7 The column-type water treatment device of Example 7 was prepared in the same manner as Example 1, except that non-porous zirconia beads (manufactured by Nikkato Corporation, "YTZ", particle size 30 μm) were used instead of diatomaceous earth in both the second treatment layer, which was a layer consisting only of diatomaceous earth, and the first treatment layer, which was a mixed layer of a mixture of sodium trititanate and diatomaceous earth.

[0083] Example 8 The column-type water treatment device of Example 8 was prepared in the same manner as in Example 1, except that in the first treatment layer, which is a mixed layer of a mixture of sodium trititanate and diatomaceous earth, layered double hydroxide (particle diameter 7.5 μm) was used instead of sodium trititanate.

[0084] <Comparative Example 1> A column-type water treatment device of Comparative Example 1 was produced in the same manner as in Example 1, except that the treatment layer having a two-layer structure was changed to a treatment layer having a single-layer structure. The single-layer treatment layer is a layer consisting only of sodium trititanate filled with sodium trititanate, formed by weighing out 1 part by mass of the sodium trititanate prepared above and pouring the weighed sodium trititanate onto filter paper placed in a column.

[0085] <Comparative Example 2> A column-type water treatment device of Comparative Example 2 was prepared in the same manner as in Example 1, except that the filter paper used as a filter was not installed at the bottom of the column, and the two-layer treatment layer was changed to a single-layer treatment layer. The single-layer treatment layer is formed by granulating the sodium trititanate prepared above using a pan-pelletizer, passing the granulated sodium trititanate through a 7-mesh sieve, and then through a 35-mesh sieve to produce granulated sodium trititanate with a particle size adjusted to a range of 0.5 mm or more and 2.8 mm or less, and then weighing out 5 parts by mass of the granulated sodium trititanate and introducing the weighed granulated sodium trititanate into a column to form a layer consisting only of granulated sodium trititanate.

[0086] (Water permeability evaluation) Pressure gauges (VSW2, manufactured by Valcom Co., Ltd.) were installed in the pipelines before the inlet and after the outlet of the column in the column-type water treatment devices fabricated in each Example and Comparative Example 1. Pure water was pumped through the column-type water treatment device while adjusting the flow rate with a tube pump (MP-2000, manufactured by Tokyo Rikakikai Co., Ltd.), and the differential pressure between the inlet where the pure water was introduced and the outlet where the pure water was discharged after passing through a treatment layer installed in the column-type water treatment device was measured. After confirming that this differential pressure was stabilized at 50 kPa, 80 kPa, 100 kPa, and 130 kPa, the pure water was passed for 10 minutes while maintaining each differential pressure, and the flow rate per hour (unit: mL / h) was measured.

[0087] (Adsorption performance evaluation) [Water flow adsorption test] Column-type water treatment devices manufactured in Example 1 and Comparative Example 2 were prepared. Zinc chloride (special grade reagent, manufactured by Kanto Chemical Co., Ltd.) was prepared as a simulant for the water to be treated. The zinc chloride was dissolved in pure water to prepare a zinc chloride aqueous solution with a zinc concentration of 8 mg / L. The prepared simulant was pumped at a flow rate of 300 mL / h using a tube pump and passed through the column-type water treatment device in each example. Treated water discharged from the column-type water treatment device was recovered every hour. From the zinc concentration of the recovered treated water, the amount of zinc ion-exchanged into the ion-exchanged inorganic crystals was calculated as the zinc adsorption amount (mmol / g-Ad) using the following formula (F1). In Table 2, the sodium trititanate used in Example 1 was not granulated and is therefore labeled "non-granulated," while the sodium trititanate used in Comparative Example 2 was granulated and is therefore labeled "granulated."

[0088] A Zn =(W1A×(W1C Zn -W2C Zn ) / IEA) / 65.4 ···(F1) (In formula (F1), A Zn is the amount of zinc adsorption (unit: mmol / g-Ad), W1A is the amount of simulated liquid (unit: L), W1C Zn is the zinc concentration of the simulated solution (unit: mg / L), W2C Zn is the zinc concentration in the treated water (unit: mg / L), and IEA is the amount of ion-exchange inorganic crystals (unit: g-Ad)

[0089] [Immersion adsorption test] For reference, an immersion adsorption test of ion-exchange inorganic crystals was conducted. Zinc chloride (special grade reagent, manufactured by Kanto Chemical Co., Ltd.) was prepared as a simulated solution for treated water. Zinc chloride was dissolved in pure water to prepare a zinc chloride aqueous solution with a zinc concentration of 210 mg / L. 120 mg of sodium trititanate alone as the ion-exchange inorganic crystal was added to 50 mL of this zinc chloride aqueous solution, and the mixture was shaken at 25°C and 160 rpm for 15 hours using a shaker (NTS-4000B, manufactured by Tokyo Rikakikai Co., Ltd.). The mixture was then filtered through a membrane filter with a pore size of 0.1 μm. The amount of zinc ion-exchanged into the ion-exchange inorganic crystal was calculated from the zinc concentration of the filtrate obtained by filtration using the above formula (F1), taking the amount of zinc ion-exchanged into the ion-exchange inorganic crystal as the zinc adsorption capacity (mmol / g-Ad). The zinc adsorption capacity of sodium trititanate as the ion-exchange inorganic crystal calculated using the above formula (F1) was 1.24 mmol / g-Ad. The zinc adsorption capacity of sodium trititanate evaluated by the immersion method is the maximum adsorption capacity.

[0090] [Table 1]

[0091] [Table 2]

[0092] The results of the water permeability evaluation showed that the column-type water treatment devices prepared in each example were able to maintain higher water permeability than the column-type water treatment device prepared in Comparative Example 1. Furthermore, the results of the adsorption performance evaluation showed that the zinc adsorption amount obtained by the water flow method in Example 1 was close to the zinc adsorption amount of non-granulated sodium trititanate alone evaluated by the immersion method. Therefore, the zinc adsorption amount obtained by the column-type water treatment device prepared in Example 1 was close to the maximum zinc adsorption amount of sodium trititanate. From the above results, it was found that the column-type water treatment devices obtained in each Example had good water permeability and suppressed a decrease in adsorption performance. [Explanation of symbols]

[0093] 10...column, 11...inlet section, 12...discharge section, 20...treatment layer, 20A...single-layer treatment layer, 21, 21A...first treatment layer, 22...second treatment layer, 30...filter, 40...inlet section side pipe, 50...discharge section side pipe, 101, 102, 103...column-type water treatment device, W1...water to be treated, W2...treated water.

Claims

1. A column-type water treatment device, a column provided with an inlet for introducing water to be treated and an outlet for discharging treated water obtained by treating the water to be treated; A treatment layer is contained inside the column and contains non-granulated ion-exchange inorganic particles and a retention aid that retains the ion-exchange inorganic particles; Equipped with Column type water treatment device.

2. 2. The column-type water treatment device according to claim 1, The treatment layer includes a mixed layer of the ion exchange inorganic particles and the retention aid. Column type water treatment device.

3. 3. The column-type water treatment device according to claim 2, A mixing ratio of the ion-exchange inorganic particles and the retention aid contained in the mixed layer (the ion-exchange inorganic particles:the retention aid) is in the range of 1:9 to 9:1 in terms of mass ratio; Column type water treatment device.

4. 2. The column-type water treatment device according to claim 1, The treatment layer has a structure of at least two layers, The treatment layer includes a layer containing the ion-exchange inorganic particles. Column type water treatment device.

5. 2. The column-type water treatment device according to claim 1, The treatment layer has a structure of at least two layers, The treatment layer includes a layer consisting of only the retention aid. Column type water treatment device.

6. 2. The column-type water treatment device according to claim 1, The treatment layer has a structure of at least two layers, a layer consisting of only the ion-exchange inorganic particles is disposed on a side of the treatment layer closer to the introduction section; In the treatment layer, a layer consisting of only the retention aid is disposed on a side closer to the discharge section than the ion-exchange inorganic particles. Column type water treatment device.

7. 3. The column-type water treatment device according to claim 2, The treatment layer has a structure of at least two layers, The mixed layer is disposed on a side of the treatment layer closer to the introduction portion, A layer consisting of only the retention aid is disposed on the treatment layer closer to the discharge section than the mixed layer. Column type water treatment device.

8. The column-type water treatment device according to any one of claims 1 to 7, The retention aid is a porous particle. Column type water treatment device.

9. The column-type water treatment device according to any one of claims 1 to 7, The retention aid is diatomaceous earth; Column type water treatment device.

10. The column-type water treatment device according to any one of claims 1 to 7, The particle size of the retention aid is larger than the particle size of the ion-exchange inorganic particles; Column type water treatment device.

11. A water treatment method for treating the water to be treated using the column-type water treatment device according to any one of claims 1 to 7, Introducing the water to be treated from the introduction part; a step of passing the water to be treated introduced from the introduction part through the treatment layer and treating the water to be treated to produce the treated water; Discharging the treated water from the discharge section; have Water treatment methods.

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