Filtration materials, water treatment materials, and water purifiers

Abstract

To provide filtration materials, water treatment materials, and water purifiers that exhibit a fast adsorption rate for heavy metal ions present in water. [Solution] A filter material containing sodium trititanate, wherein the time required for ion exchange to be completed is 7 seconds or less, as measured by the following method. [Measurement Method] 2 mL of water and 40 mg of the filter material are placed in a glass test tube to make a sample solution. 0.5 mL of a model solution, which is a nitric acid solution with a lead ion concentration of 9.5 g / L, is dropped into the sample solution at once, and time-resolved X-ray diffraction measurement is performed in synchronization with the dropping of the model solution to obtain an X-ray diffraction pattern obtained by exposing the X-rays for 333 milliseconds at 50 millisecond intervals. The obtained diffraction pattern is analyzed, and the time from when the diffraction peak (2θ=2.8°) of the filter material that has not exchanged and adsorbed lead ions begins to decrease until it disappears is defined as the time required for ion exchange to be completed.

Description

[Technical Field]

[0001] This invention relates to filtration materials, water treatment materials, and water purifiers. [Background technology]

[0002] Japanese tap water is among the safest in the world. However, in areas where old water pipes remain, rust and lead can contaminate the tap water. Looking at the world, there are regions where metal contamination of drinking water from old metal water pipes is a problem. For example, if heavy metal ions such as lead ions and iron ions are ingested by the human body, they may have adverse effects on health.

[0003] For these reasons, there is a need for a filtration material that exhibits adsorption performance for heavy metal ions present in water. Furthermore, since a faster adsorption rate of heavy metal ions allows for more rapid filtration, a high adsorption rate is required.

[0004] For example, Non-Patent Document 1 discloses a composite material in which the time to reach the maximum adsorption amount of lead ions is 240 seconds, while Non-Patent Documents 2 and 3 disclose a composite material in which the time to reach the maximum adsorption amount of lead ions is 180 seconds. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Alam, MM, et al., Evaluation of heavy metal kinetics through pyridine based Th(IV) phosphate composite cation exchanger using particle diffusion controlled ion exchange phenomenon. Journal of Industrial and Engineering Chemistry, 2014. 20(2): p. 705-709. [Non-Patent Document 2] Naushad, M., et al., Ion-exchange kinetic studies for Cd(II), Co(II), Cu(II), and Pb(II) metal ions over a composite cation exchanger. Desalination and Water Treatment, 2015. 54(10): p. 2883-2890. [Non-Patent Document 3] Talha, M. and M. Naushad, Ion Exchange Kinetics of Heavy Metal Ions on Organic-Inorganic Composite Cation Exchanger Poly-o-toluidine Zr(IV) Tungstate. Journal of Inorganic and Organometallic Polymers and Materials, 2012. 22(4): p. 822-829. [Overview of the project] [Problems that the invention aims to solve]

[0006] From the perspective of making drinking water purification easier, there is a need for further improvement in the adsorption rate of heavy metal ions. The present invention has been made in view of the above circumstances, and aims to provide a filtration material, a water treatment material, and a water purifier that have a fast adsorption rate for heavy metal ions present in water. [Means for solving the problem]

[0007] The present invention encompasses the following aspects. [1] A filter material containing sodium trititanate, wherein the time required for ion exchange to be completed, as measured by the following method, is 7 seconds or less. [Measurement method] Place 2 mL of water and 40 mg of filter material into a glass test tube to prepare the sample solution. Insert a micro-stirrer with a length of 6 mm and a diameter of 3 mm into the glass test tube and stir the sample solution using a magnetic stirrer. The glass test tube used has an inner diameter of 8 mm, an outer diameter of 10 mm, and a length of 75 mm. While continuing to stir, 0.5 mL of a model solution, which is a nitric acid solution with a lead ion concentration of 9.5 g / L, is added dropwise to the sample solution at one time. Time-resolved X-ray diffraction measurements are performed in synchronization with the addition of the model solution, and an X-ray diffraction pattern is obtained by exposing the sample to X-rays (wavelength 0.049694 nm) for 333 milliseconds at 50 millisecond intervals. The obtained diffraction pattern is analyzed, and the time from when the diffraction peak (2θ=2.8°) of the filter material that has not exchanged and adsorbed lead ions begins to decrease until it disappears is defined as the time until ion exchange is completed. [2] BET specific surface area is 7.0 m 2 / g or more 20.0m 2 The filtration material described in [2] is less than or equal to / g. A water treatment material comprising the filtration material described in [3] [1] or [2] and activated carbon. A water purifier comprising the filtration material described in [4][1] or [2]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a filtration material, a water treatment material, and a water purifier that have a fast adsorption rate for heavy metal ions present in water. [Brief explanation of the drawing]

[0009] [Figure 1] This is a map showing the relationship between the diffraction angle (2θ) and time when using the filtration material of Example 1. [Figure 2] This graph shows the time dependence of the diffraction angle (2θ) when using the filtration material of Example 1. [Figure 3] This graph shows the time dependence of the diffraction peak area when using the filtration material of Example 1. [Figure 4] This figure shows the adsorption rate curve of lead ions. [Figure 5]It is a diagram showing the adsorption rate curve of lead ions. [Figure 6] It is a diagram showing a scanning electron micrograph of the filter material produced in Example 1. [Figure 7] It is a diagram showing a scanning electron micrograph of the filter material produced in Comparative Example 1.

Mode for Carrying Out the Invention

[0010] <Filter Material> The present embodiment relates to a filter material containing sodium trititanate, which cation-adsorbs heavy metal ions contained in an aqueous solution. In the filter material of the present embodiment, a cation component that undergoes ion exchange with heavy metal ions is contained between the layers of the layered crystal structure. For this reason, the filter material exhibits high adsorption performance for heavy metal ions.

[0011] For the filter material of the present embodiment, the time until completion of ion exchange, measured by the following method, is 7 seconds or less.

[0012] [Measurement Method] Put 2 mL of water and 40 mg of the filter material into a glass test tube to prepare a sample solution. A micro rotor with a length of 6 mm and a diameter of 3 mm is placed in the glass test tube, and the sample solution is stirred with a magnetic stirrer. A test tube with an inner diameter of 8 mm, an outer diameter of 10 mm and a length of 75 mm is used as the glass test tube. While continuing stirring, 0.5 mL of a model solution, which is a nitric acid solution with a lead ion concentration of 9.5 g / L, is added dropwise to the sample solution at one time, time-resolved X-ray diffraction measurement synchronized with the dropping of the model solution is performed, and an X-ray diffraction pattern obtained by exposing X-rays (wavelength: 0.049694 nm) for 333 milliseconds at 50-millisecond intervals is obtained. The obtained diffraction pattern is analyzed, and the time from when the diffraction peak (2θ=2.8°) of the filter material that has not exchanged and adsorbed lead ions starts to decrease until it disappears is defined as the time until ion exchange is completed.

[0013] The stirring speed by the magnetic stirrer is set to 200 to 400 rpm. Furthermore, the time required for ion exchange to be completed will be measured at room temperature.

[0014] Time-resolved X-ray diffraction (hereinafter sometimes referred to as "time-resolved XRD") allows observation of changes in crystal structure caused by ion exchange. Here, "changes in crystal structure caused by ion exchange" refers to changes resulting from the ion exchange of sodium ions, which are located between the layers of sodium trititanate having a layered crystal structure, with heavy metal ions.

[0015] In one embodiment of the present invention, the process of ion exchange between sodium ions and heavy metal ions can be visualized by continuously measuring the process at 50-millisecond intervals using time-resolved XRD with the BL02B2 beamline at SPring-8, for example. Furthermore, by performing time-resolved XRD synchronized with the dropping of the model solution, the time from the start to the end of the ion exchange reaction can be measured.

[0016] "Time-resolved XRD synchronized with the dropping of the model solution" means that the time-resolved XRD may be started simultaneously with the dropping of the model solution, or the dropping of the model solution may be started within a few seconds of the start of the time-resolved XRD measurement. In this invention, X-ray diffraction patterns are obtained by continuously measuring at 50-millisecond intervals for 333 milliseconds using time-resolved XRD.

[0017] The obtained X-ray diffraction pattern is analyzed. A Gaussian function is fitted to the diffraction peak (2θ=2.8°) of the filter material that does not adsorb lead ions, and the resulting peak area is plotted against time. The time from when the peak area begins to decrease until it becomes zero is defined as the time until ion exchange is complete.

[0018] Since there is a time lag of approximately 5 seconds between the time the entire model solution is added and the time when lead ions begin to diffuse into the sample solution, the ion exchange time is defined as the difference between the time when the area of ​​the diffraction peak (2θ=2.8°) of the filter material begins to decrease and the time when the peak area becomes zero.

[0019] The model solution containing lead ions used in the measurement method described above is a model of an aqueous solution containing heavy metal ions. Therefore, by using the filter material of this embodiment, heavy metal ions other than lead ions can be removed from the aqueous solution. Examples of heavy metal ions that can be removed include aluminum ions, cadmium ions, chromium ions, copper ions, iron ions, manganese ions, nickel ions, and zinc ions.

[0020] As a result of tracking the structural transition of the filter material using the method described above, it was found that ion exchange is possible in 7 seconds or less with the filter material of the present invention. Considering that, as disclosed in Non-Patent Documents 1 to 3 above, the time to reach the maximum adsorption amount of lead ions in conventional methods is at least 180 seconds, the filter material of the present invention is a filter material with a remarkably fast adsorption rate for heavy metal ions. Since it takes approximately 7 seconds for the heavy metal ions to diffuse after dropping the model solution into the sample solution, ion exchange can be completed in a time roughly equivalent to the completion of heavy metal ion diffusion.

[0021] The filtration material in this embodiment contains sodium trititanate. Sodium trititanate contains sodium ions, which are cations. Sodium ions and heavy metal ions can exchange ions. Therefore, filter materials containing sodium trititanate can remove multiple types of heavy metal ions present in water.

[0022] In one embodiment of this invention, the filter material is a powder. In one embodiment of this design, the filter material is granular.

[0023] In one embodiment of this product, the content of sodium trititanate in the total amount of the filter material is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The upper limit is not particularly limited and may include 100% by mass or less, 99% by mass or less, and 98% by mass or less.

[0024] The above upper and lower limits can be combined in any way. Examples of combinations include sodium trititanate content in the total amount of filter material of 50% to 100% by mass, 70% to 99% by mass, and 90% to 98% by mass.

[0025] In one embodiment of this invention, components other than sodium trititanate that the filter material may contain include, for example, ion-exchangeable titanate compounds. In one embodiment of this product, the filter material is made of sodium trititanate.

[0026] The BET specific surface area of ​​the filter material is 7.0 m². 2 / g or more 20.0m 2 Preferably less than / g, and 7.5m 2 / g or more 18.0m 2 More preferably less than / g, and 8.0m 2 / g or more 16.0m 2 A value of less than or equal to / g is even more preferable.

[0027] The BET specific surface area of ​​the filter material can be measured using a BET specific surface area measuring device. For example, the BELSORP®-mini X manufactured by Microtrac-Bel can be used as a BET specific surface area measuring device. When measuring powdered filter material, it is preferable to pre-treat it by drying it at 150°C for 1 hour under reduced vacuum.

[0028] The filtration material in this embodiment may be a powder or granules made of sodium trititanate. The filtration material in this embodiment may be a molded body obtained by solidifying sodium trititanate powder or granules with a binder.

[0029] The binder can be any material that can bond with the sodium trititanate contained in the filter material and form micropores between the sodium trititanate and the binder; it is not particularly limited. Examples include polyolefins such as polyethylene and polypropylene, carboxymethylcellulose, bentonite, kaolin, and attuple guide.

[0030] The amount of binder added is not particularly limited. For example, it may be 10% to 40% by mass relative to the filter material. When the binder content relative to the filter material is 10% by mass or more, the bond between the filter materials becomes sufficient, making it easier to form a molded body. Furthermore, if the amount is 40% by mass or less, it will not excessively cover the surface of the filter material, thus maintaining the filtration performance of the filter material.

[0031] ≪Method for manufacturing filtration materials≫ The method for producing the filtration material of the present invention will be described below. The filtration material of the present invention can be manufactured by a manufacturing method comprising the steps of mixing a titanium compound and a sodium organic salt to obtain a mixture, and a calcination step of calcining the mixture. The following describes each step.

[0032] [Steps to obtain the mixture] First, a titanium compound, a sodium organic acid salt, and sodium carbonate are mixed to obtain a mixture. In this embodiment, the titanium compound, the powdered sodium organic acid salt, and the sodium carbonate may be mixed dry or wet. In the case of dry mixing, powdered titanium compound is mixed with powdered sodium organic acid salt and sodium carbonate to obtain a mixed powder. In wet mixing, a slurry is obtained by dispersing a mixture of powdered titanium compound, powdered sodium organic acid salt, and sodium carbonate in water. The mixture may also be made by mixing a nitrate or hydroxide instead of sodium carbonate. That is, a mixture may be obtained by mixing a titanium compound with a powdered sodium organic acid salt and a nitrate or hydroxide.

[0033] The method for obtaining the mixture is not particularly limited as long as it involves stirring and mixing the titanium compound, sodium organic acid salt, and sodium carbonate, and a commercially available stirring mixer can be used as appropriate.

[0034] Titanium dioxide is preferred as the titanium compound used in this embodiment.

[0035] In this embodiment, a sodium organic acid salt is a compound in which some or all of the carboxyl groups of an organic acid are substituted with sodium. In the case of an organic acid having two or more carboxyl groups in its molecule, all carboxyl groups may be substituted with sodium, or some of the carboxyl groups may be substituted with sodium. The organic acid is a material containing carbon.

[0036] The sodium organic acid salt used in this embodiment is preferably a sodium salt of one or more organic acids selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, lactic acid, malic acid, tartaric acid, citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, aconitic acid, pyruvic acid, oxaloacetate, benzoic acid, phthalic acid, and alginic acid.

[0037] In this embodiment, it is even more preferable that the sodium organic salt is one or more selected from the group consisting of sodium formate, trisodium citrate, sodium tartrate, sodium oxalate, and sodium acetate.

[0038] In this embodiment, the mixing ratio of the sodium organic acid salt and the titanium compound is preferably 2:3 in terms of the molar ratio of sodium to titanium.

[0039] In this embodiment, the mixing ratio of the titanium compound to the sodium organic acid salt is preferably 4:3 to 2:1 in molar ratio, and more preferably 3:2.

[0040] In this embodiment, the mixture preferably consists of a titanium compound, a sodium organic acid salt, and sodium carbonate.

[0041] In this embodiment, examples of combinations of titanium compounds with sodium organic acid salts and sodium carbonate are described below. A combination of titanium dioxide, sodium acetate, and sodium carbonate. A combination of titanium dioxide, trisodium citrate, and sodium carbonate. A combination of titanium dioxide, sodium oxalate, and sodium carbonate. A combination of titanium dioxide, sodium tartrate, and sodium carbonate. A combination of titanium dioxide, sodium formate, and sodium carbonate.

[0042] [Firing process] The resulting mixture is fired at a firing temperature of 600°C or lower. In this embodiment, "firing temperature" refers to the set temperature of the firing apparatus. If there are multiple firing steps, it refers to the highest temperature among each firing step.

[0043] The firing temperature is preferably 450°C to 600°C, and more preferably 500°C to 580°C. Because the above mixture is used in the manufacturing method of the filter material of this embodiment, a layered crystalline structure can be grown even when fired at a low temperature of 600°C or less.

[0044] The holding time at the firing temperature is preferably 5 hours to 15 hours, and more preferably 7 hours to 12 hours.

[0045] Furthermore, the firing atmosphere may be an oxidizing gas atmosphere such as air or oxygen, or an inert gas atmosphere such as nitrogen, argon, or carbon dioxide. A mixture of these gases may also be used. In this embodiment, an atmospheric atmosphere or an oxygen atmosphere is preferred. If an atmospheric atmosphere is used, it is preferable to include oxygen to the extent that gaseous components other than oxygen become inert to the workpiece at temperatures below the firing temperature.

[0046] In this embodiment, the heating rate is preferably 0.5°C / min or more and 50°C / min or less, preferably 0.5°C / min or more and 10°C / min or less, and more preferably 1°C / min or more and 5°C / min or less.

[0047] In this embodiment, when calcining a mixture of a titanium compound and a sodium organic acid salt, it is preferable to raise the temperature at a rate of 1°C / min to 5°C / min and hold it at a calcination temperature of 400°C to 650°C for 7 hours to 12 hours.

[0048] In this embodiment, when calcining a mixture of a titanium compound, a sodium organic acid salt, and sodium carbonate, it is preferable to raise the temperature at a rate of 1°C / min to 5°C / min and to hold it at a calcination temperature of 400°C to 650°C for 7 hours to 12 hours.

[0049] The firing apparatus used in this embodiment is not particularly limited as long as it is capable of firing the obtained mixture at 600°C or below, and any commercially available electric furnace can be used as appropriate. An example of an electric furnace that can be used in this embodiment is the FO100 electric furnace manufactured by Yamato Scientific Co., Ltd.

[0050] <Water treatment materials> This embodiment is a water treatment material comprising the filtration material of this embodiment and activated carbon. The filtration material of this embodiment may be used in mixture with activated carbon. By adjusting the mixing ratio of the filtration material and activated carbon, it is possible to adjust, for example, the balance of the size, replacement cycle, and cost of the water purifier cartridge.

[0051] Activated carbon used in water treatment materials is preferably in powder form.

[0052] <Water purifier> This embodiment is a water purifier equipped with the filtration material of the above embodiment. The filtration material of this embodiment can be suitably used as a filter medium for water purifiers.

[0053] The water purifier of this embodiment is a water purifier intended to remove impurities such as heavy metals contained in tap water. The water purifier can be installed in known configurations such as a faucet-mounted type attached to the tap, a countertop type installed on the sink, or an under-sink type (built-in type) installed in a storage cabinet under the sink.

[0054] Alternatively, a pitcher-type water purifier may be used in homes, etc., that can purify about 1 to 2 liters of raw water at once and can be stored directly in a refrigerator or the like. An example of a pitcher-type water purifier is one having an outer container, an inner container that is detachably attached to the outer container and divides the inside of the outer container into upper and lower sections, and a water purification cartridge that is attached to the inner container.

[0055] Alternatively, the filtration material of this embodiment may be filled into a water purification cartridge that is detachably installed inside the water purifier.

[0056] Furthermore, it may be used as a filtration material to remove heavy metal ions in water treatment plants, sewage treatment plants, factories, etc. [Examples]

[0057] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0058] <Method for measuring the time required for ion exchange to be completed> Into a glass test tube (inner diameter 8 mm, outer diameter 10 mm, length 75 mm), 2 mL of water and 40 mg of filtration material were placed to obtain a sample solution. A micro rotor with a length of 6 mm and a diameter of 3 mm was placed in the glass test tube, and the sample solution was stirred with a magnetic stirrer. 0.5 mL of a model solution, which is a nitric acid solution with a lead ion concentration of 9.5 g / L, was added dropwise to the sample solution at one time, and time-resolved X-ray diffraction measurement synchronized with the dropping of the model solution was performed (SPring-8 BL02B2 beamline). X-ray diffraction patterns were obtained by exposing X-rays (wavelength 0.049694 nm) for 333 milliseconds at 50-millisecond intervals. The obtained diffraction pattern was analyzed, and the time from when the diffraction peak (2θ = 2.8°) of the filtration material that had not exchange-adsorbed lead ions began to decrease until it disappeared was defined as the time required for ion exchange to complete. Since there is a time lag of about 5 seconds from when the entire amount of the model solution is added until lead ions begin to diffuse into the sample solution, the difference between the time when the area of the diffraction peak (2θ = 2.8°) of the filtration material begins to decrease and the time when the peak area becomes zero was defined as the ion exchange time.

[0059] A Gaussian function is fitted to the diffraction peak (2θ = 2.8°) of the filtration material that has not exchange-adsorbed lead ions, and the obtained peak area is plotted against time. Then, the time from when the peak area begins to decrease until it becomes zero is defined as the time required for ion exchange to complete.

[0060] <BET specific surface area> The BET specific surface area of the filtration material was measured using BELSORP (registered trademark)-mini X manufactured by MicrotracBEL Corp.

[0061] <Example 1> Anatase-type titanium(IV) oxide, sodium formate, and sodium carbonate were mixed at a molar ratio of TiO2:HCOONa:Na2CO3 = 3:2:1 to obtain a powdery mixture 1. Mixture 1 was calcined using an electric furnace FO100 manufactured by Yamato Scientific Co., Ltd. The calcination conditions were as follows: after heating from room temperature (about 20°C) at a heating rate of 5°C / min, the temperature was maintained at a calcination temperature of 550°C for 5 hours. The calcined powder was washed with water and dried to obtain filtration material 1.

[0062] A powder X-ray diffraction experiment was performed on the obtained filtration material 1, using CuKα as incident X-rays and setting the scanning range of diffraction angle 2θ to 5 degrees or more and 80 degrees or less. As a result, it was confirmed that filtration material 1 was sodium trititanate (Na2Ti3O7).

[0063] Using filtration material 1, the time required for completion of ion exchange was measured by the method described in the above <Method for measuring time until completion of ion exchange>. Figure 1 is a map diagram showing the relationship between diffraction angle (2θ) and time. In Figure 1, the time axis is set to "0" at the time point when all of the model solution has been added. From Figure 1, it can be confirmed that after all the model solution was added, the diffraction peak at 2θ=2.8° started to decrease around 5 seconds and disappeared around 13 seconds. Furthermore, after that, the occurrence of a diffraction peak at 2θ=3.1° was confirmed. The diffraction peak at 2θ=2.8° is the diffraction peak of the filtration material that has not exchanged and adsorbed lead ions, and the diffraction peak at 2θ=3.1° is the diffraction peak of the filtration material that has completed exchange and adsorption of lead ions.

[0064] Figure 2 is a graph showing the time dependence of diffraction angle (2θ) from 5 seconds to 12 seconds after all the model solution was added. As shown in Figure 2, the diffraction peak at 2θ=2.8° started to decrease around 5 seconds and disappeared at 12 seconds.

[0065] Figure 3 is a graph showing the time dependence of the area of the diffraction peak at 2θ=2.8°. As shown in Figure 3, the area of the diffraction peak at 2θ=2.8° started to decrease around 5 seconds and disappeared at 12 seconds.

[0066] The BET specific surface area of filtration material 1 produced in Example 1 was 9.32 m 2 / g. Figure 6 shows a scanning electron microscope image of the filter material 1 manufactured in Example 1.

[0067] <Comparative Example 1> 10.782 g of TiO2 and 7.383 g of sodium acetate were mixed to obtain powdered mixture 2. Mixture 2 was placed in a 30 mL lidded alumina crucible. Mixture 2 was calcined using an electric furnace FO100 manufactured by Yamato Scientific Co., Ltd. The calcination conditions were as follows: the temperature was raised from room temperature (approximately 20°C) at a rate of 5°C / min, and then maintained at a calcination temperature of 600°C for 10 hours. Next, the power to the electric furnace was turned off, and the furnace was allowed to cool naturally. As a result, filter material 2 was obtained.

[0068] Powder X-ray diffraction experiments were conducted on the obtained filter material 2, using CuKα as the incident X-ray and with a diffraction angle 2θ scanning range of 5 degrees to 80 degrees. The results confirmed that filter material 2 is sodium trititanate (Na2Ti3O7).

[0069] The BET specific surface area of ​​filter material 2 manufactured in Comparative Example 1 was 6.52 m². 2 It was / g. Figure 7 shows a scanning electron microscope image of filtration material 2 produced in Comparative Example 1.

[0070] ≪Pb 2+ Adsorption rate test for solution Initial concentration of 50 ppm Pb adjusted to pH 4.0-5.6 2+ The solution and the filter material from Example 1 or Comparative Example 1 were mixed at a ratio of 1000 ml / g, and the amount of Pb adsorbed at each reaction time shown in Table 1 was measured.

[0071] [Table 1]

[0072] In Table 1, the maximum Pb adsorption amount represents the adsorption amount over 3600 seconds. As shown in Table 1, the time required to achieve 50% adsorption relative to the maximum adsorption amount was approximately 60 seconds for Comparative Example 1, while it was approximately 10 seconds for Example 1.

[0073] The Pb adsorption rate curves obtained using the results in Table 1 are shown in Figures 4 and 5. Figure 4 shows the adsorption rate test results for the first 5 minutes of the test, and Figure 5 shows the adsorption rate curve from the start of the test to 1 hour. The results in Figure 5 show that the filtration material in Example 1 undergoes a dramatic adsorption reaction immediately after the start of the test.

Claims

1. A filter material containing sodium trititanate, A filter material in which the time required for ion exchange to be completed, as measured by the following method, is 7 seconds or less. [Measurement method] Place 2 mL of water and 40 mg of filter material into a glass test tube to prepare the sample solution. A micro-rotor measuring 6 mm in length and 3 mm in diameter is placed in the glass test tube, and the sample liquid is stirred using a magnetic stirrer. The glass test tube used has an inner diameter of 8 mm, an outer diameter of 10 mm, and a length of 75 mm. While continuing to stir, 0.5 mL of a model solution, which is a nitric acid solution with a lead ion concentration of 9.5 g / L, is added dropwise to the sample solution at one time. Time-resolved X-ray diffraction measurements are performed in synchronization with the addition of the model solution, and an X-ray diffraction pattern is obtained by exposing the sample to X-rays (wavelength 0.049694 nm) for 333 milliseconds at 50 millisecond intervals. The obtained diffraction pattern is analyzed, and the time from when the diffraction peak (2θ = 2.8°) of the filter material that has not exchanged and adsorbed lead ions begins to decrease until it disappears is defined as the time until ion exchange is completed.

2. BET specific surface area is 7.0 m² ２ / g or more 20.0m ２ The filtration material according to claim 1, wherein the amount is less than or equal to / g.

3. A water treatment material comprising the filtration material and activated carbon described in claim 1 or 2.

4. A water purifier comprising the filtration material described in claim 1 or 2.

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