Zeolite molded body

Abstract

To provide at least one of a molded body containing zeolite that is capable of removing potassium from dialysis drainage while being suppressed in elution of aluminum in comparison to processing of dialysis drainage using conventional zeolite, and a potassium absorption method using the molded body.SOLUTION: A molded body includes: zeolite having an oxygen 8-membered ring structure; and at least one of a silica binder and a zirconia binder. A ratio of a cumulative pore volume of pore diameters of 10 nm or more and 100 nm or less to a cumulative pore volume of pore diameters of 5 nm or more and 300 nm or less is 25 vol.% or more and 70 vol.% or less. In addition, the molded body satisfies the following (1) or (2): (1) an average aspect ratio is 1.55 or less, and a particle diameter D50 is 200 μm or more and 600 μm or less; and (2) the average aspect ratio is greater than 1.55.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to zeolite molded articles. [Background technology]

[0002] Hemodialysis is a process that artificially removes waste products from the blood using dialysate. By bringing the blood and dialysate into contact through a semipermeable membrane, waste products, mainly potassium, are removed from the blood. Hemodialysis involves using a large amount of dialysate per session and is performed frequently. Therefore, after hemodialysis, a large amount of dialysate is discharged and processed as wastewater (dialysis effluent). In recent years, home dialysis, in which dialysis patients perform hemodialysis at home, has attracted attention from the perspective of improving quality of life, but the handling of dialysis effluent is hindering its widespread adoption.

[0003] Incidentally, compared to ion exchange resins and the like, zeolites are also known as readily available potassium adsorbents. For this reason, the treatment of dialysis wastewater using zeolites is being considered for the purpose of treating and regenerating dialysis wastewater.

[0004] For example, Patent Document 1 reports that potassium can be removed from dialysate and regenerated by treating the dialysate with FAU-type zeolites that have different SiO2 / Al2O3 ratios. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2015 / 0297815 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in the treatment of dialysis wastewater using zeolite as described in Patent Document 1, there was a problem in that aluminum leached out in parallel with potassium removal and mixed into the dialysis wastewater.

[0007] The present disclosure aims to provide at least one of a molded body containing a zeolite capable of suppressing elution of aluminum and removing potassium from dialysis effluent, as compared with conventional treatment of dialysis effluent using zeolite, and a potassium adsorption method using the molded body.

Means for Solving the Problems

[0008] [[ID=⑧]] [[ID=⑨]]The inventors focused on the structure of zeolite and the form when used for treating dialysis effluent, regarding the zeolite used for removing potassium from dialysis effluent. As a result, it was found that a molded body containing a zeolite having a specific structure and with the pore state controlled is less likely to cause elution of aluminum and exhibits excellent potassium adsorption characteristics. [[ID=⑩]] [[ID=⑪]]

[0009] [[ID=⑫]] [[ID=⑬]]That is, the present invention is as described in the claims, and the gist of the present disclosure is as follows. [[ID=⑭]] [[ID=⑮]][1] A molded body containing a zeolite having an oxygen 8-membered ring structure and at least one of a silica binder and a zirconia binder, and the ratio of the cumulative pore volume with a pore diameter of 10 nm or more and 100 nm or less to the cumulative pore volume with a pore diameter of 5 nm or more and 300 nm or less is 25% by volume or more and 70% by volume or less, and satisfying the following (1) or (2). [[ID=⑯]] [[ID=⑰]]

[0010] [[ID=⑱]] [[ID=⑲]](1) The average aspect ratio is 1.55 or less, and [[ID=⑳]] [[ID=㉑]]The particle size D50 is 200 μm or more and 600 μm or less [[ID=㉒]] [[ID=㉓]](2) The average aspect ratio is more than 1.55 [[ID=㉔]] ] [[ID=㉕]][2] The molded body according to [1] above, which contains a zeolite having an oxygen 8-membered ring structure and at least one of a silica binder and a zirconia binder, and the ratio of the cumulative pore volume with a pore diameter of 10 nm or more and 100 nm or less to the cumulative pore volume with a pore diameter of 5 nm or more and 300 nm or less is 25% by volume or more and 70% by volume or less, and the average aspect ratio is more than 1.55. [[ID=㉖]] [3] A zeolite having an oxygen 8-membered ring structure, and containing at least one of a silica binder and a zirconia binder, and having a ratio of the cumulative pore volume with a pore diameter of 10 nm or more and 100 nm or less to the cumulative pore volume with a pore diameter of 5 nm or more and 300 nm or less of 25% by volume or more and 70% by volume or less, an average aspect ratio of 1.55 or less, and a particle size D50 of 200 μm or more and 600 μm or less, the molded body according to [1] above. [4] The cumulative pore area with a pore diameter of 5 nm or more and 300 nm or less is 10.0 m 2 / g or more and 35.0 m 2 / g or less, the molded body according to any one of [1] to [3] above. [5] The cumulative pore volume with a pore diameter of 5 nm or more and 300 nm or less is 0.35 mL / g or more and 0.70 mL / g or less, the molded body according to any one of [1] to [4] above. [6] The pore diameter at which the cumulative pore volume is 50% by volume with respect to the cumulative pore volume with a pore diameter of 5 nm or more and 300 nm or less is 75 nm or more and 160 nm or less, the molded body according to any one of [1] to [5] above. [7] The ratio of the cumulative pore volume with a pore diameter of 5 nm or more and 10 nm or less to the cumulative pore volume with a pore diameter of 5 nm or more and 300 nm or less is 0.1% by volume or more and 5.0% by volume or less, the molded body according to any one of [1] to [6] above. [8] The zeolite is a zeolite having one or more framework structures selected from the group consisting of FER structure, HEU structure, YFI structure, MAZ structure, CHA structure, MER structure, and MOR structure, the molded body according to any one of [1] to [7] above. [9] The molar ratio of silica to alumina (SiO2 / Al2O3 ratio) of the zeolite is 3 or more and 100 or less, the molded body according to any one of [1] to [8] above.

[10] A potassium adsorption method having a step of bringing the molded body according to any one of [1] to [9] above into contact with a solution containing potassium ions.

[11] A column containing the molded body according to any one of [1] to [9] above.

[12] A potassium adsorption system comprising the column described in

[11] above. [Effects of the Invention]

[0011] This disclosure provides at least one of the following: a molded body containing a zeolite that suppresses aluminum elution and removes potassium from dialysate compared to conventional zeolite-based dialysate treatment; and a potassium adsorption method using the molded body. [Modes for carrying out the invention]

[0012] The present disclosure will be described below with reference to an example of its embodiment. The terms used in this embodiment are defined as follows. Furthermore, each configuration and parameter disclosed herein can be in any combination, and the upper and lower limits of the values ​​disclosed herein also include any combination of ranges. The main terms used in this disclosure are shown below.

[0013] Aluminosilicate is a composite oxide having a structure consisting of repeating networks of aluminum (Al) and silicon (Si) mediated by oxygen (O). Because aluminum and silicon have different charge levels, to compensate for the charge, for example, H + or Na + Such countercations exist. Among aluminosilicates, those that have a crystalline XRD peak in their powder X-ray diffraction (hereinafter also referred to as "XRD") pattern are called "crystalline aluminosilicates," and those that do not have a crystalline XRD peak are called "amorphous aluminosilicates."

[0014] A "zeolite" is a compound in which the skeletal atoms (hereinafter also referred to as "T atoms") have a regular structure mediated by oxygen (O), and the T atoms consist of at least one of a metal atom and / or a metalloid atom. Examples of metal atoms include one or more selected from the group consisting of aluminum (Al), titanium (Ti), iron (Fe), zinc (Zn), gallium (Ga), and tin (Sn), and it is preferable that the T atom is at least one of aluminum and iron, and more preferably aluminum. Examples of metalloid atoms include at least one selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te), and it is preferable that the T atom is silicon.

[0015] A "zeolite-like substance" is a compound in which the T atom has a regular structure mediated by oxygen, and which contains at least one atom other than metals and metalloids (hereinafter also referred to as a "nonmetallic atom") in the T atom. Phosphorus (P) can be given as an example of a nonmetallic atom. Examples of zeolite-like substances include complex phosphorus compounds containing phosphorus (P) as the T atom, such as aluminophosphate (AlPO) and silicoaluminophosphate (SAPO).

[0016] The "regular structure" (hereinafter also referred to as "zeolite structure") in zeolites and zeolite-like materials is a skeletal structure identified by a structural code (hereinafter simply referred to as "structural code") defined by the Structure Commission of the International Zeolite Association (IZA). For example, the FER structure is a skeletal structure identified by the structural code "FER". The FER structure can be identified by comparing it with the XRD pattern (hereinafter also referred to as "reference pattern") described for FER in the Zeolite Framework Types on the IZA's Structure Commission website: http: / / www.iza-struture.org / databases / . In relation to zeolite structures, the terms skeletal structure, crystalline structure, and crystalline phase are used synonymously.

[0017] In this embodiment, "FER-type zeolite" and other "~-type zeolites" refer to zeolites having the zeolite structure of the said structural code, and preferably refer to crystalline aluminosilicate having the zeolite structure of the said structural code.

[0018] An "oxygen 8-membered ring structure" is a cyclic structure consisting of eight T atoms, also known as a micropore.

[0019] A "zeolite molded article" is a composition in which powdered zeolite maintains a certain shape, and may not consist solely of zeolite, but may also include zeolite plus at least one of a binder and a molding aid. In this disclosure, the terms "molded article" and "zeolite molded article" are used interchangeably.

[0020] The molded body of this embodiment will be described below.

[0021] This embodiment is a molded article comprising a zeolite having an 8-membered oxygen ring structure, and at least one of a silica binder and a zirconia binder, wherein the 10-100 nm pore volume ratio is 25% by volume or more and 70% by volume or less, and satisfies either (1) or (2) below.

[0022] (1) The average aspect ratio is 1.55 or less, and The particle size D50 is between 200 μm and 600 μm. (2) The average aspect ratio is greater than 1.55 The molded article of this embodiment is a molded article mainly composed of zeolite, a so-called zeolite molded article, and in particular contains zeolite having an 8-membered oxygen ring structure (hereinafter also referred to as "8-membered ring zeolite"), and at least one of silica binder and zirconia binder (hereinafter also referred to as "inorganic binder").

[0023] The zeolite contained in the molded body of this embodiment has an 8-membered oxygen ring structure. Having an 8-membered oxygen ring structure makes it easier for potassium to enter the pores inside the molded body of this embodiment during the treatment of dialysis wastewater, and also makes it more difficult for potassium adsorbed on the zeolite to detach from the zeolite. The 8-membered ring zeolite has the following structures: ABW, ACO, AEI, AEN, AFN, AFT, AFX, ANA, APC, APD, ATN, ATT, ATV, AWO, AWW, BCT, BIK, BRE, CAS, CDO, CHA, DDR, DFT, EAB, EDI, EPI, ERI, ESV, FER, GIS, GME, GOO, HEU, IHW, ITE, and ITW. Examples of zeolites include those having one or more skeletal structures selected from the group consisting of JBW structure, KFI structure, LEV structure, LTA structure, LTL structure, MAZ structure, MER structure, MON structure, MOR structure, MTF structure, NSI structure, OFF structure, OWE structure, PAU structure, PHI structure, RHO structure, RTE structure, RTH structure, RWR structure, SAS structure, SAT structure, SAV structure, SIV structure, SZR structure, THO structure, TSC structure, UEI structure, UFI structure, VNI structure, YFI structure, YUG structure, and ZON structure. Since the selectivity for potassium is improved by the arrangement of oxygen atoms contained in the 8-membered oxygen ring structure, the 8-membered ring zeolite is preferably a zeolite having one or more skeletal structures selected from the group consisting of FER structure, HEU structure, YFI structure, MAZ structure, CHA structure and MOR structure, more preferably a zeolite having one or more skeletal structures selected from the group consisting of FER structure, HEU structure, YFI structure, MAZ structure, CHA structure and MOR structure, even more preferably a zeolite having one or more skeletal structures selected from the group consisting of FER structure, HEU structure, YFI structure and MOR structure, and even more preferably a zeolite having an FER structure, HEU structure, YFI structure or MOR structure. Particularly preferred 8-membered ring zeolites include zeolites having an FER structure, MER structure or MOR structure, and even more preferably zeolites having an FER structure (FER-type zeolite).

[0024] The molar ratio of silica to alumina (SiO2 / Al2O3 ratio) of the 8-membered ring zeolite is preferably 3 or more, 7 or more, 10 or more, 13 or more, or 15 or more, and also preferably 100 or less, 80 or less, 50 or less, or 35 or less. Such an SiO2 / Al2O3 ratio tends to improve potassium adsorption performance from dialysate. The upper and lower limits of the SiO2 / Al2O3 ratio can be any combination of the above, for example, 3 to 100, 7 to 80, or 15 to 35.

[0025] For the 8-membered ring zeolite, at least one of cation type: Na (sodium) or cation type: H (proton) is preferred, with cation type: Na being more preferred, as it easily improves potassium adsorption performance from dialysate.

[0026] The primary particle size of the 8-membered ring zeolite is preferably 0.1 μm or more and 15 μm or less.

[0027] The particle size D50 of the 8-membered ring zeolite is preferably between 1 μm and 100 μm.

[0028] The molded article of this embodiment contains an inorganic binder, preferably a silica binder. Including a silica binder as the inorganic binder tends to reduce aluminum leaching when in contact with a solution such as dialysis wastewater. Furthermore, the adhesion between the 8-membered ring zeolite and the silica contained in the silica binder tends to improve the strength of the molded article. On the other hand, the molded article of this embodiment may also contain a zirconia binder as the inorganic binder. The adhesion between the zeolite and the zirconia contained in the zirconia binder tends to improve the strength of the molded article.

[0029] The silica binder is a compound mainly containing silicon (Si) and oxygen (O), preferably a compound containing silica (SiO2), and more preferably silica.

[0030] The zirconia binder is a compound mainly containing zirconium (Zr) and oxygen (O), preferably a compound containing zirconia (ZrO2), and more preferably zirconia.

[0031] The inorganic binder included in the molded article of this embodiment may be either a silica binder or a zirconia binder alone, or it may contain both.

[0032] The primary particle size of the inorganic binder is preferably between 10 nm (0.010 μm) and 150 nm (0.150 μm). More preferably, the primary particle size of the inorganic binder is between 10 nm (0.010 μm) and 20 nm (0.020 μm) in order to promote adhesion with the zeolite. On the other hand, more preferably, the primary particle size of the inorganic binder is between 70 nm (0.070 μm) and 120 nm (0.120 μm) in order to prevent elution into the dialysis effluent.

[0033] The particle size D50 of the silica binder is preferably between 15 μm and 40 μm. Furthermore, the particle size D50 of the zirconia binder is preferably between 0.05 μm and 40 μm.

[0034] The particle size of the 8-membered ring zeolite and the particle size D50 of the inorganic binder are both the particle size corresponding to the D50 (median diameter) of the volume particle size distribution obtained by laser diffraction and scattering using a general particle size distribution analyzer (e.g., instrument name: MT-3100II, manufactured by Microtrac-Bel).

[0035] The molded body of this embodiment is more likely to have improved potassium adsorption properties while maintaining the strength of the molded body. For this reason, it is preferable that the mass of the inorganic binder per 100 parts by mass (anhydrous mass) of 8-membered ring zeolite is 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more, and also 40 parts by mass or less, 30 parts by mass or less, or 25 parts by mass or less. For example, if the amount of inorganic binder per 100 parts by mass (anhydrous mass) of 8-membered ring zeolite is 10 parts by mass or more and 40 parts by mass or less, 15 parts by mass or more and 30 parts by mass or less, or 20 parts by mass or more and 25 parts by mass or less, the amount of aluminum leaching tends to be lower.

[0036] The anhydrous equivalent masses of the 8-membered ring zeolite and the inorganic binder are those obtained after heat treatment at 600°C for 1 hour in an air atmosphere. The anhydrous equivalent mass of the molding aid is also obtained after heat treatment at 80°C for 1 hour in an air atmosphere.

[0037] The molded article of this embodiment preferably contains a zeolite having an 8-membered oxygen ring structure, and at least one of a silica binder and a zirconia binder, and more preferably the ratio of the cumulative pore volume of pores with a diameter of 10 nm to 100 nm to the cumulative pore volume of pores with a diameter of 5 nm to 300 nm is 25% to 70% by volume, and the average aspect ratio is greater than 1.55. By satisfying such an average aspect ratio, a molded article exhibiting high potassium adsorption performance is obtained regardless of the particle size D50.

[0038] In terms of increasing the surface area of ​​the molded body, which increases the contact area with the dialysate, an average aspect ratio of over 1.55 is preferable, over 1.55 and 2.70 or less is more preferable, 1.60 or more and 2.60 or less is even more preferable, and 1.80 or more and 2.55 or less is even more preferable.

[0039] In this embodiment, the "aspect ratio" of the molded body is a value expressed as the ratio of the major axis to the minor axis of the molded body, and the "average aspect ratio" is the average value of the aspect ratios. The major axis and minor axis of the molded body can be determined by taking the longer side of the rectangle that circumscribes the molded body image obtained when the independently observed molded bodies are projected onto the same plane using a scanning electron microscope (hereinafter also referred to as "SEM"), and taking the shorter side of the rectangle as the major axis [μm] and the minor axis [μm], respectively. Therefore, the "aspect ratio" will be 1.00 or greater. SEM observation can be performed using a general scanning electron microscope (for example, device name: JSM-IT200, manufactured by JEOL Ltd.) under the following conditions.

[0040] Acceleration voltage: 6kV Magnification: 30±10x The average aspect ratio of the molded body in this embodiment can be calculated by taking the arithmetic mean of the aspect ratios of 50 ± 5 molded bodies observed using the method described above.

[0041] The molded article of this embodiment preferably has an average minor diameter of 150 μm or more and 700 μm or less, more preferably 200 μm or more and 650 μm or less, and even more preferably 400 μm or more and 650 μm or less. The "average minor diameter" of the molded article is the average value of the minor diameters of the molded article, and can be calculated by taking the arithmetic mean of the minor diameters of 50 ± 5 molded articles observed by SEM observation in the same manner as described above.

[0042] The molded article of this embodiment may contain a zeolite having an 8-membered oxygen ring structure, and at least one of a silica binder and a zirconia binder, and the ratio of the cumulative pore volume of pores with a diameter of 10 nm to 100 nm to the cumulative pore volume of pores with a diameter of 5 nm to 300 nm is 25% to 70% by volume, the average aspect ratio is 1.55 or less, and the particle size D50 is 200 μm to 600 μm.

[0043] When the average aspect ratio is 1.55 or less, the contribution of the particle size D50 to the potassium adsorption performance becomes larger. By having both such an average aspect ratio and particle size D50, potassium adsorption performance tends to be high. In terms of easily improving the packing density of the molded body, an average aspect ratio of more than 1.00 and 1.55 or less is preferred, and 1.30 or more and 1.50 or less is more preferred.

[0044] When the average aspect ratio of the molded body in this embodiment is 1.55 or less, its particle size D50 is 200 μm or more and 600 μm or less. If the particle size D50 of the molded body is less than 200 μm, the flow rate of dialysis effluent and the like slows down. On the other hand, if the particle size D50 exceeds 600 μm, the molded body itself becomes too large. As a result, it becomes difficult for dialysis effluent to penetrate into the molded body, and the potassium removal efficiency from the dialysis effluent becomes too low. The particle size D50 of the molded body in this embodiment is preferably 250 μm or more, 300 μm or more, or 350 μm or more, and also preferably 550 μm or less, 500 μm or less, or 450 μm or less. The upper and lower limits of the particle size D50 can be any combination as described above. For example, if the limits are 250 μm to 550 μm, 300 μm to 500 μm, or 350 μm to 450 μm, the amount of aluminum eluted will be suppressed without a decrease in potassium adsorption characteristics.

[0045] The particle size D50 of the molded body is the particle size corresponding to the D50 (median diameter) of the volume particle size distribution obtained by laser diffraction and scattering using a general particle size distribution analyzer (e.g., instrument name: MT-3100II, manufactured by Microtrac-Bell). The following are specific measurement conditions.

[0046] Pretreatment: Dry at 110°C for 1 hour under an air atmosphere. Measurement range: 0.7 to 1000 μm Transparency: Transparent Shape: Non-spherical Refractive index: 1.66 Atmosphere: Air (dry type) Solvent refractive index: 1 For the molded body of the present embodiment, the ratio of the cumulative pore volume with a pore diameter of 10 nm or more and 100 nm or less (hereinafter also referred to as "10-100 nm pore volume ratio") to the cumulative pore volume with a pore diameter of 5 nm or more and 300 nm or less (hereinafter also referred to as "total pore volume") is 25% by volume or more and 70% by volume or less. When the 10-100 nm pore volume ratio of the molded body is less than 25% by volume, the adsorption capacity of potassium tends to decrease. When it exceeds 70% by volume, other ions are likely to be adsorbed, and the selectivity of potassium tends to decrease. The 10-100 nm pore volume ratio of the molded body of the present embodiment is preferably 30% by volume or more, 33% by volume or more, 43% by volume or more, or 53% by volume or more, and is preferably 69% by volume or less, 67% by volume or less, or 65% by volume or less. The upper and lower limits of the 10-100 nm pore volume ratio may be any combination of the above, for example, 25% by volume or more and 70% by volume or less, 30% by volume or more and 70% by volume or less, 33% by volume or more and 69% by volume or less, 43% by volume or more and 67% by volume or less, 53% by volume or more and 65% by volume or less.

[0047] The cumulative pore area of the molded body of the present embodiment with a pore diameter of 5 nm or more and 300 nm or less (hereinafter also referred to as "total pore area") is 10.0 m 2 / g or more, 20.0 m 2 / g or more, or 25.0 m 2 / g or more, and is preferably 35.0 m 2 / g or less or 32.0 m 2 / g or less. The upper and lower limits of the total pore area may be any combination of the above, for example, 10.0 m 2 / g or more and 35.0 m 2 / g or less, 20.0 m 2 / g or more and 35.0 m 2 / g or less, or 25.0 m 2 / g or more and 32.0 m 2 / g or less.

[0048] The total pore volume of the molded article in this embodiment is preferably 0.35 mL / g or more, 0.36 mL / g or more, or 0.38 mL / g or more, and also preferably 0.70 mL / g or less, 0.60 mL / g or less, 0.50 mL / g or less, 0.48 mL / g or less, or 0.45 mL / g or less. The upper and lower limits of the total pore volume may be any combination of the above, for example, 0.35 mL / g or more and 0.70 mL / g or less, 0.35 mL / g or more and 0.60 mL / g or less, 0.35 mL / g or more and 0.50 mL / g or less, 0.36 mL / g or more and 0.60 mL / g or less, 0.36 mL / g or more and 0.50 mL / g or less, 0.36 mL / g or more and 0.48 mL / g or less, or 0.38 mL / g or more and 0.45 mL / g or less.

[0049] The combination of total pore area and total pore volume, as well as their respective upper and lower limits, can be any combination as described above, and the total pore area can be, for example, 10.0 m². 2 / g or more 35.0m 2 / g or less, 20.0m 2 / g or more 32.0m 2 / g or less, or 25.0m 2 / g or more 32.0m 2 One example is that it must be less than or equal to / g. Furthermore, the upper and lower limits of the total pore volume may be any combination of the above, for example, 0.35 mL / g or more and 0.50 mL / g or less, 0.36 mL / g or more and 0.48 mL / g or less, or 0.38 mL / g or more and 0.45 mL / g or less.

[0050] The aforementioned total pore area or total pore volume allows the dialysis drain to penetrate the molded body more easily, resulting in improved potassium adsorption performance.

[0051] In this embodiment, the molded article preferably has a pore diameter (hereinafter also referred to as "pore diameter D50") such that the cumulative pore volume is 50% of the total pore volume, which is between 75 nm and 160 nm. The pore diameter D50 is preferably 76 nm or more, 80 nm or more, or 100 nm or more, and more preferably 155 nm or less, 120 nm or less, 118 nm or less, 116 nm or less, or 114 nm or less. The upper and lower limits of the pore diameter D50 can be any combination of the above, and examples of pore diameter D50 include 76 nm or more and 160 nm or less, 80 nm or more and 160 nm or less, 100 nm or more and 155 nm or less, 75 nm or more and 155 nm or less, 75 nm or more and 120 nm or less, 76 nm or more and 118 nm or less, 80 nm or more and 116 nm or less, or 100 nm or more and 114 nm or less.

[0052] Having a pore size D50 within the above range tends to result in higher potassium adsorption performance.

[0053] In the molded article of this embodiment, the ratio of the cumulative pore volume of pores with a diameter of 5 nm to 10 nm to the total pore volume (hereinafter also referred to as the "5-10 nm pore volume ratio") is preferably 0.1 volume% to 5.0 volume%. The 5-10 nm pore volume ratio is preferably 1.5 volume% or more, 2.2 volume% or more, or 3.1 volume% or more, and also preferably 4.9 volume% or less, 4.1 volume or less, or 3.7 volume% or less. When the 5-10 nm pore volume ratio is in the above proportions, potassium adsorption tends to be faster. The upper and lower limits of the 5-10 nm pore volume ratio can be any combination of the above, for example, 1.5 volume% to 4.9 volume%, 2.2 volume% to 4.1 volume%, or 3.1 volume% to 3.7 volume%.

[0054] The pore area, pore volume, and pore diameter of the molded body can be measured by the mercury intrusion method in accordance with JIS Z 1655. Specific measurement conditions include the following:

[0055] Sample mass: 0.10g Mercury introduction pressure: 601.6 psia ~ 36,098.1 psia (4.1 MPa ~ 248.9 MPa) Measuring pore diameter: 5nm~300nm Cell used: Glass cell with an indentation volume of 1.1cc Mercury surface tension: 480dyn Mercury contact angle: 130° Pretreatment conditions: Degassing treatment at 110°C in an air atmosphere for at least 1 hour (1 to 3 hours). A standard mercury porosimeter (for example, the Autopore 9510, manufactured by Micromeritics) can be used for the measurement.

[0056] The bulk density of the molded body in this embodiment is 0.1 g / cm³. 3 More than 0.65g / cm 3 Preferably, the bulk density is 0.1 g / cm³. 3 If the bulk density is above 0.65 g / cm³, the molded product becomes easier to handle. 3 The following conditions allow for high packing efficiency without excessively obstructing the flow of dialysis drainage. The bulk density of the molded body in this embodiment is 0.1 g / cm³. 3 More than 0.2g / cm 3 or more, or 0.3 g / cm³ 3 That's all, and also 0.65 g / cm³ 3 Below 0.60g / cm 3 The following or 0.58 g / cm³ 3 The following is preferable. The upper and lower limits of bulk density can be any combination of the above, for example, 0.1 g / cm³. 3 More than 0.65g / cm 3 Below, 0.2g / cm 3 More than 0.60g / cm 3 The following, or 0.3 g / cm³ 3 More than 0.58g / cm 3 The following is acceptable.

[0057] The molded body of this embodiment can be formed into a desired shape suitable for the purpose. The shape of the molded body of this embodiment can be one or more selected from the group consisting of cylindrical, pellet-shaped, bead-shaped, substantially spherical, and ring-shaped, and furthermore, it can be at least one of cylindrical and bead-shaped, or any shape suitable for the application.

[0058] The molded body of this embodiment is suitable for removing potassium from dialysis wastewater. For example, the potassium adsorption evaluation of the molded body of this embodiment using the following simulated dialysis fluid (hereinafter also referred to as "simulated adsorption evaluation") showed that potassium (K + The removal rate is preferably 20% or more, 30% or more, or 40% or more, and also 100% or less, 99% or less, or 98% or less. The simulated adsorption evaluation can be performed as follows: an aqueous solution containing KCl, NaCl, MgCl2, and CaCl2 with the following composition is prepared and used as the simulated dialysis solution.

[0059] K: 1.0 mEq / L Na: 132.0 mEq / L Mg: 0.5 mEq / L Ca: 3.5 mEq / L Next, 2.5 mL of the molded body of this embodiment is packed into a glass column with an inner diameter of 8.4 mmφ, and simulated dialysate is flowed through the glass column at a flow rate of 100 mL / min. The simulated dialysate discharged from the glass column is collected every 100 mL from the start of discharge, for a total of 500 mL, and each is diluted 10-fold with pure water to prepare the measurement solution. After measuring the concentrations of potassium, calcium, and magnesium in the measurement solution obtained by ICP emission spectrometry using a general ICP-AES instrument (e.g., OPTIMA3000DV, manufactured by PERKIN-ELMER), the potassium removal rate can be determined from the following equations (1) and (2).

[0060] Potassium removal rate [%] = (A1 + A2 + A3 + A4 + A5) / 5 × 100 (1) In equation (1), A1 to A5 are the potassium removal rates [%] of each measurement solution.

[0061] Potassium removal rate [%] for each measurement solution = (C0 - Cn) / C0 × 100 (2) In equation (2), C0 is the potassium concentration of the simulated dialysate [1.0 mEq / L], and Cn is the potassium concentration in each measurement solution [mEq / L].

[0062] Prior to the simulated adsorption evaluation, the molded body of this embodiment can be pre-treated by mixing it with 1 L of a sodium chloride aqueous solution with a NaCl concentration of 10% by mass, and then washing it with 1.5 L of pure water.

[0063] In simulated adsorption evaluation, the magnesium removal rate and calcium removal rate are preferably lower than the potassium removal rate, for example, magnesium (Mg 2+ The removal rate is said to be 15% or less, 10% or less, or 6% or less. On the other hand, calcium (Ca 2+ The removal rate may also be 15% or less, 10% or less, or 6% or less.

[0064] Examples of lower limits for magnesium removal rates and calcium removal rates include 0% or higher, 0.5% or higher, and 1.0% or higher, respectively.

[0065] However, the calcium removal rate or magnesium removal rate can be determined by replacing potassium in equations (1) and (2) above with calcium or magnesium.

[0066] The molded article of this embodiment exhibits minimal aluminum leaching when in contact with solutions such as dialysis wastewater. For example, the molded article of this embodiment exhibits aluminum leaching levels of 0.01 ppm to 0.50 ppm, 0.01 ppm to 0.20 ppm, or 0.01 ppm to 0.15 ppm in the following aluminum leaching evaluations.

[0067] To evaluate aluminum elution, 1 mL of the molded body of this embodiment is mixed with 10 mL of pure water, and then shaken at 37°C for 6 hours at 1.0 ± 0.5 Hz. After shaking, the supernatant is filtered through a membrane filter to obtain the measurement solution. The aluminum content of the measurement solution can be measured by ICP emission spectrometry using an ICP-AES (product name: OPTIMA3000DV, manufactured by PERKIN-ELMER), and this can be used as the amount of aluminum eluted.

[0068] Prior to evaluating aluminum elution, the sample should be pre-treated by mixing it with 1 L of a 10% by mass sodium chloride aqueous solution and then washing it with 1.5 L of pure water.

[0069] In the above-mentioned aluminum elution evaluation, a low amount of aluminum elution is preferable, but for example, it should be 0 ppm or more by mass or 0.01 ppm or more by mass.

[0070] The molded body of this embodiment is suitable for removing potassium from dialysis wastewater, but it may also be used in a potassium adsorption method that includes a step of contacting a solution containing potassium ions.

[0071] Furthermore, the molded body of this embodiment may be used as an adsorbent for selective removal of potassium from a solution containing at least two alkali metal ions and alkaline earth metal ions. The molded body of this embodiment can be used as a potassium adsorbent, a potassium adsorbent from a solution containing at least one of sodium and magnesium, and potassium, and as an adsorbent for removing potassium from at least one of biological fluids, blood products, blood, and dialysate.

[0072] The molded body of this embodiment can be packed into a column and used as a column containing the molded body of this embodiment in a potassium adsorption method, and can also be used as a potassium adsorption system equipped with the column.

[0073] Next, the method for manufacturing the molded article of this embodiment will be described.

[0074] The method for manufacturing the molded article of this embodiment includes an 8-membered ring zeolite and an inorganic binder source, and any method for manufacturing the molded article having the above configuration is acceptable.

[0075] A preferred manufacturing method includes, for example, a mixing step of mixing an 8-membered ring zeolite and an inorganic binder source to obtain a mixture, and a molding step of molding the mixture to obtain a molded body.

[0076] In the mixing process, the 8-membered ring zeolite and the inorganic binder source can be mixed using any method to ensure uniformity. Examples of mixing methods include using one or more devices selected from the group consisting of a ribbon blender, kneader, Nauter mixer, and Mix Morar.

[0077] The primary particle size and particle size D50 of the 8-membered ring zeolite and inorganic binder source used in the mixing process are not particularly limited, as long as they result in the molded body described above.

[0078] In the mixing process, it is preferable to mix the 8-membered ring zeolite and the inorganic binder such that the amount of inorganic binder per 100 parts by weight (anhydrous equivalent mass) of 8-membered ring zeolite is 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more, and also 40 parts by mass or less, 30 parts by mass or less, or 25 parts by mass or less.

[0079] The inorganic binder source can be any compound that, upon calcination, contains silicon (Si) and oxygen (O), preferably silica (SiO2), more preferably silica, or a compound containing zirconium (Zr) and oxygen (O), preferably zirconia (ZrO2), more preferably zirconia, and functions as an inorganic binder. Preferably, it is one or more selected from the group consisting of silica sol, colloidal silica, wet silica, dry silica, dry zirconia, wet zirconia, zirconia sol, zirconium hydroxide, zirconium carbonate, zirconium carbonate ammonium, zirconium oxynitrate, zirconium oxychloride, zirconium oxysulfate, zirconium acetate, and zirconium oxyacetate. More preferably, it is one or more selected from the group consisting of colloidal silica, zirconium acetate, zirconium oxyacetate, wet zirconia, zirconia sol, and zirconium hydroxide. At least one of colloidal silica and zirconia sol is even more preferred. Examples of specific colloidal silica include at least one of sodium ion-stabilized colloidal silica and ammonium ion-stabilized colloidal silica. Furthermore, examples of the properties of the inorganic binder source include a solid, slurry, colloidal solution, or aqueous solution containing the above-mentioned compounds.

[0080] During the mixing process, a molding aid may be added as needed. A molding aid is a substance that improves moldability, and its use makes it easier to control the pore structure of the molded product. Examples of molding aids include one or more selected from the group consisting of cellulose, alcohol, lignin, starch, and guar gum. Because they are easy to handle, at least one of cellulose and alcohol is preferred as the molding aid. Examples of cellulose include one or more selected from the group consisting of crystalline cellulose, hydroxypropyl methylcellulose, and sodium carboxymethylcellulose (CMC). Examples of alcohol include at least one of polyvinyl alcohol and ethylene glycol.

[0081] The amount of the molding aid is preferably 1 part by mass or more, 2 parts by mass or more, 5 parts by mass or less, or 4 parts by mass or less, per 100 parts by mass of zeolite (anhydrous equivalent mass).

[0082] In the molding process, the mixture obtained in the mixing process is molded into a desired shape. Any molding method that can produce the desired shape is acceptable. For example, cylindrical molded bodies can be molded by extrusion, and bead-shaped molded bodies can be molded by at least one of the rolling granulation method and the stirring granulation method.

[0083] When manufacturing a molded body with an average aspect ratio greater than 1.55, a molding method that allows for cylindrical molding is preferred, and extrusion molding is more preferred, as it allows for easier control of the short and long diameters of the molded body. A specific method of extrusion molding is to use a general extruder (for example, product name: MG-55-1, manufactured by Dalton) to mold the mixture obtained in the above mixing step into a cylindrical shape with a diameter of 0.1 mm to 10.0 mm. The average aspect ratio tends to increase as the diameter from which the mixture is extruded decreases.

[0084] When manufacturing a molded body with an average aspect ratio of 1.55 or less, the molding process is preferably one that can form the product into a roughly spherical or spherical shape, as this makes it easier to reduce the average aspect ratio. Molding by at least one of the rolling granulation method and the stirring granulation method is more preferable. As an example of the stirring granulation method, a method is used in which a general stirring granulation apparatus (for example, product name: FM Mixer (FM5), manufactured by Nippon Coke Industries Co., Ltd.) is used to form a bead-shaped molded body from the mixture obtained in the above mixing process.

[0085] The method for manufacturing the molded article of this embodiment may include a firing step in which the molded article is heat-treated as needed. The firing step can increase the strength of the molded article. The firing conditions are arbitrary as long as at least a portion of the inorganic binder source melts and fuses with the 8-membered ring zeolite, but examples include firing at 500°C to 900°C for 2 hours to 4 hours. The firing atmosphere can be an oxidizing atmosphere, for example, an air atmosphere. [Examples]

[0086] The present disclosure will be described in more detail below in the form of examples. However, the present disclosure is not limited to these examples. <Simulated Adsorption Evaluation> The potassium adsorption performance of the sample was evaluated using simulated dialysate.

[0087] Specifically, an aqueous solution containing KCl, NaCl, MgCl2, and CaCl2 as a potassium solution was prepared with the following composition and used as a simulated dialysate.

[0088] K: 1.0 mEq / L Na: 132.0 mEq / L Mg: 0.5 mEq / L Ca: 3.5 mEq / L A 2.5 mL sample was packed into a glass column with an inner diameter of 8.4 mm, and simulated dialysate was flowed through the glass column at a flow rate of 100 mL / min.

[0089] The simulated dialysate discharged from the glass column was collected in 100 mL increments from the start of discharge, for a total of 500 mL. Each of these was then diluted 10-fold with pure water to prepare the measurement solution.

[0090] After measuring the concentrations of potassium, calcium, and magnesium in the sample solution obtained by ICP emission spectroscopy using an ICP-AES instrument (product name: OPTIMA3000DV, manufactured by PERKIN-ELMER), the potassium removal rate, calcium removal rate, and magnesium removal rate were determined from equations (1) and (2) above, respectively.

[0091] Prior to the simulated adsorption evaluation, the sample was pretreated by mixing it with 1 L of a 10% by mass sodium chloride aqueous solution and then washing it with 1.5 L of pure water. <Aluminum elution evaluation> The aluminum elution evaluation of the sample was measured using the following method.

[0092] Specifically, 1 mL of the sample was mixed with 10 mL of pure water, and then shaken at 37°C for 6 hours at 1.0 ± 0.5 Hz. After shaking, the supernatant was filtered through a membrane filter to obtain the measurement solution. The aluminum content of the measurement solution was measured by ICP emission spectrometry using an ICP-AES (product name: OPTIMA3000DV, manufactured by PERKIN-ELMER), and this was defined as the amount of aluminum eluted.

[0093] Prior to the aluminum elution evaluation, the sample was pre-treated by mixing it with 1 L of a 10% by mass sodium chloride aqueous solution and then washing it with 1.5 L of pure water. <Measurement of pore diameter and pore volume> The pore volume and pore diameter of the sample were measured using a mercury porosimeter (instrument name: Autopore 9510, manufactured by Micromeritics) by the mercury intrusion method in accordance with JIS Z 1655. The specific measurement conditions for porosity and pore diameter were as follows:

[0094] Sample weight: 0.10g Mercury introduction pressure: 601.6 psia ~ 36,098.1 psia (4.1 MPa ~ 248.9 MPa) Measuring pore diameter: 5nm~300nm Cell used: Glass cell with an indentation volume of 1.1cc Mercury surface tension: 480dyn Mercury contact angle: 130° Pretreatment conditions: Degassing treatment at 110°C for at least 1 hour in an air atmosphere. <Measurement of particle size distribution> The particle size distribution of the sample was measured using laser diffraction and scattering. A general particle size distribution analyzer (device name: MT-3100II, manufactured by Microtrac-Bell) was used for the measurement. The measurement conditions were as follows:

[0095] Pretreatment: Dry at 110°C for 1 hour under an air atmosphere. Measurement range: 0.7 to 1000 μm Transparency: Transparent Shape: Non-spherical Refractive index: 1.66 Atmosphere: Air (dry type) Solvent refractive index: 1 Example 1 100 parts by mass (anhydrous equivalent mass: 300.0 g) of FER-type zeolite (product name: HSZ(registered trademark)-720KOA, manufactured by Tosoh Corporation, SiO2 / Al2O3 ratio: 18, particle size D50: 8.7 μm), 20 parts by mass (anhydrous equivalent mass: 60.0 g) of sodium ion-stabilized colloidal silica (product name: ST-30, manufactured by Nissan Chemical Corporation, Si concentration converted to SiO2: 30% by mass, primary particle size: 12 nm), and 4 parts by mass (anhydrous equivalent mass: 12.0 g) of sodium-type carboxymethylcellulose (product name: Sunrose F-20LC, manufactured by Nippon Paper Industries Co., Ltd.) were stirred and mixed for 5 minutes using a stirring granulator (product name: FM Mixer (FM5), manufactured by Nippon Coke Industries Co., Ltd.). 105.4 g of pure water was added to the mixture and stirred for a further 5 minutes. Subsequently, the material was dried overnight in an air atmosphere at 100°C. Then, it was classified using a rotary sieve shaker (product name: IIDA SHAVE SHAKER, manufactured by Iida Seisakusho Co., Ltd.) under conditions of impact frequency of 165 rpm, rotation speed of 290 rpm, and processing time of 5 minutes. The material was further passed through a sieve with a mesh size of 300 μm, and the molded body deposited on a sieve with a mesh size of 180 μm was collected. The collected molded body was then fired in an air atmosphere at 600°C for 2 hours to obtain a bead-shaped molded body containing FER-type zeolite (8-membered ring zeolite) and silica (silica binder).

[0096] 500.0 g of a 10% by mass NaCl aqueous solution was passed through the bead-shaped molded body and ion exchange was performed to obtain the molded body of this example with a cation type of Na.

[0097] Example 2 The molded body of this example was obtained in the same manner as in Example 1, except that the molded body passed through a sieve with a mesh size of 425 μm and was collected after being deposited on a sieve with a mesh size of 300 μm.

[0098] Example 3 The molded body of this example was obtained in the same manner as in Example 1, except that it was mixed for 60 minutes in a mixer (Hibismix: manufactured by Primix Corporation), then molded into a 0.5 mm cylindrical shape in an extruder (product name: MG-55-1, manufactured by Dalton Corporation), dried, then crushed using a granulation device (product name: FXB-3, manufactured by Fuji Powder Corporation) at a hammer rotation speed of 15 Hz, and the molded body that passed through a sieve with a mesh size of 425 μm and accumulated on a sieve with a mesh size of 300 μm was collected.

[0099] Example 4 The molded articles of this example were obtained in the same manner as in Example 1, except that ammonium ion-stabilized colloidal silica (product name: ST-N-30G, manufactured by Nissan Chemical Corporation, Si concentration in terms of SiO2: 30% by mass, primary particle size: 12.5 nm ± 2.5 nm) was used instead of sodium ion-stabilized colloidal silica.

[0100] Example 5 The molded body of this example was obtained in the same manner as in Example 1, except that ammonium ion-stabilized colloidal silica (product name: ST-N-30G, manufactured by Nissan Chemical Corporation, Si concentration in terms of SiO2: 30% by mass, primary particle size: 12.5 nm ± 2.5 nm) was used instead of sodium ion-stabilized colloidal silica, and the molded body that passed through a sieve with a mesh size of 425 μm and was deposited on a sieve with a mesh size of 300 μm was collected.

[0101] Example 6 The molded articles of this example were obtained using the same method as in Example 1, except that FER-type zeolite (product name: HSZ(registered trademark))-720NHA, manufactured by Tosoh Corporation, with an SiO2 / Al2O3 ratio of 18 and particle size D50 of 10.9 μm, was acid-treated with 1 ml / L hydrochloric acid to produce an H-type cation, and ammonium ion-stabilized colloidal silica (product name: ST-N-30G, manufactured by Nissan Chemical Corporation, Si concentration in terms of SiO2: 30% by mass, primary particle size: 12.5 nm ± 2.5 nm) was used instead of sodium ion-stabilized colloidal silica.

[0102] Example 7 The molded body of this example was obtained in the same manner as in Example 6, except that the molded body passed through a sieve with a mesh size of 425 μm and was collected after being deposited on a sieve with a mesh size of 300 μm.

[0103] Example 8 100 parts by mass (anhydrous equivalent mass: 300.0 g) of FER-type zeolite (product name: HSZ(registered trademark)-720KOA, manufactured by Tosoh Corporation; SiO2 / Al2O3 ratio: 18; particle size D50: 8.7 μm), 20 parts by mass (anhydrous equivalent mass: 60.0 g) of zirconia binder (product name: NanoYouth ZR, manufactured by Nissan Chemical Corporation; Zr concentration converted to ZrO2: 40% by mass; primary particle size: 90 nm), and 4 parts by mass (anhydrous equivalent mass: 12.0 g) of sodium-type carboxymethylcellulose (product name: Sunrose F-20LC, manufactured by Nippon Paper Industries Co., Ltd.) were mixed in a mixer (Hibismix: manufactured by Primix Corporation) for 60 minutes. 252.5 g of pure water was added to the mixture and stirred for a further 5 minutes. The mixture was then molded into a cylindrical shape with a diameter of 0.3 mm using an extruder (product name: MG-55-1, manufactured by Dalton). The mixture was dried overnight at 100°C in an air atmosphere, and then pulverized using a granulation device (product name: FXB-3, manufactured by Fuji Powder Co., Ltd.) at a hammer rotation speed of 15 Hz to obtain a molded body. The obtained molded body was classified using a rotary sieve shaker (product name: IIDA SHAVE SHAKER, manufactured by Iida Seisakusho Co., Ltd.) under conditions of impact frequency of 165 rpm, rotation speed of 290 rpm, and processing time of 5 minutes. The molded body that passed through a sieve with a mesh size of 710 μm and accumulated on a sieve with a mesh size of 180 μm was collected. The collected molded body was fired at 600°C for 2 hours in an air atmosphere to obtain a cylindrical molded body containing FER-type zeolite (8-membered ring zeolite) and zirconia (zirconia binder).

[0104] 500.0 g of a 10% by mass NaCl aqueous solution was passed through the cylindrical molded body and ion exchange was performed to obtain the molded body of this example with a cation type of Na.

[0105] Example 9 The molded body of this example was obtained in the same manner as in Example 8, except that 20 parts by mass (anhydrous mass: 60.0 g) of sodium ion-stabilized colloidal silica (product name: SH-3, manufactured by Fuso Chemical Industries, Ltd., Si concentration in terms of SiO2: 34.4% by mass, primary particle size: 35.6 nm) were used instead of zirconia binder, 174.0 g of pure water was added to the mixture, and the recovered molded body was calcined at 800°C for 2 hours in an atmospheric environment.

[0106] Example 10 The molded body of this example was obtained in the same manner as in Example 9, except that 10 parts by mass (anhydrous mass: 30.0 g) of sodium ion-stabilized colloidal silica (product name: SH-3, manufactured by Fuso Chemical Industries, Ltd., Si concentration in terms of SiO2: 34.4% by mass, primary particle size: 35.6 nm) were mixed, 230.1 g of pure water was added to the mixture, and the mixture was molded into a cylindrical shape with a diameter of 0.5 mm using an extruder.

[0107] Example 11 The molded article of this example was obtained in the same manner as in Example 9, except that 15 parts by mass (anhydrous mass: 45.0 g) of sodium ion-stabilized colloidal silica (product name: SH-3, manufactured by Fuso Chemical Industries, Ltd., Si concentration in terms of SiO2: 34.4% by mass, primary particle size: 35.6 nm) were mixed, and 63.6 g of pure water was added to the mixture.

[0108] Comparative Example 1 The molded articles of this comparative example were obtained in the same manner as in Example 1, except that FAU-type zeolite (product name: HSZ(registered trademark)-320NAA: manufactured by Tosoh Corporation, SiO2 / Al2O3 ratio: 5.7, particle size D50: 6.3 μm) was used as the zeolite.

[0109] Comparative Example 2 The molded body of this comparative example was obtained in the same manner as in Example 1, except that the molded body that passed through a sieve with a mesh size of 1.2 mm and accumulated on a sieve with a mesh size of 1.0 mm was collected.

[0110] Comparative Example 3 A commercially available FER-type zeolite molded body (product name: HSZ(registered trademark)-720KOD1C, 1.5 mmφ cylindrical pellets, binder: clay, SiO2 / Al2O3 ratio: 18, particle size D50: (zeolite) 8.7 μm, (binder) 12 μm) was crushed in a mortar, then passed through a sieve with a mesh size of 425 μm, and a cylindrical pellet molded body was obtained by depositing it on a sieve with a mesh size of 300 μm.

[0111] 500.0 g of a 10% by mass NaCl aqueous solution was passed through the cylindrical pellet molded body and ion exchange was performed to obtain the molded body of this comparative example, with the cation type being Na.

[0112] Comparative Example 4 100 parts by mass of MOR-type zeolite (product name: HSZ(registered trademark)-620HOA, manufactured by Tosoh Corporation; SiO2 / Al2O3 ratio: 18, particle size D50: 10.1 μm), 20 parts by mass (anhydrous equivalent mass: 60.0 g) of sodium ion-stabilized colloidal silica (product name: SH-3, manufactured by Fuso Chemical Industries, Ltd.; Si concentration converted to SiO2: 34.4% by mass, primary particle size: 35.6 nm), and 4 parts by mass (anhydrous equivalent mass: 12.0 g) of sodium-type carboxymethylcellulose (product name: Sunrose F-20LC, manufactured by Nippon Paper Industries Co., Ltd.) were mixed in a mixer (Hibismix: manufactured by Primix Corporation) for 60 minutes. 95.1 g of pure water was added to the mixture and stirred for a further 5 minutes. The mixture was then molded into a 1.0 mm cylindrical shape using an extruder (product name: MG-55-1, manufactured by Dalton Co., Ltd.), dried overnight at 100°C in an air atmosphere, and then pulverized using a granulation device (product name: FXB-3, manufactured by Fuji Powder Co., Ltd.) at a hammer rotation speed of 15 Hz to obtain a molded body. The obtained molded body was classified using a rotary sieve shaker (product name: IIDA SHAVE SHAKER, manufactured by Iida Seisakusho Co., Ltd.) under conditions of impact frequency of 165 rpm, rotation speed of 290 rpm, and processing time of 5 minutes. The molded body that passed through a sieve with a mesh size of 1.2 mm and accumulated on a sieve with a mesh size of 1.0 mm was collected. The collected molded body was calcined at 600°C for 2 hours in an air atmosphere to obtain a cylindrical molded body containing MOR-type zeolite (8-membered ring zeolite) and silica (silica binder).

[0113] 500.0 g of a 10% by mass NaCl aqueous solution was passed through the cylindrical molded body and ion exchange was performed to obtain the molded body of this example with a cation type of Na.

[0114] The evaluation results for the examples and comparative examples are shown in the table below.

[0115] [Table 1]

[0116] [Table 2] [Industrial applicability]

[0117] The molded articles of this disclosure have a pore size distribution and particle size useful for adsorbing and removing potassium ions, and can therefore be usefully used for applications that adsorb potassium contained in a solution, preferably for applications that adsorb potassium from wastewater containing potassium ions generated by hemodialysis.

Claims

1. A zeolite having an 8-membered oxygen ring structure, and comprising at least one of a silica binder and a zirconia binder, wherein the ratio of the cumulative pore volume of pores between 10 nm and 100 nm to the cumulative pore volume of pores between 5 nm and 300 nm is 25% to 70%, the average aspect ratio is 1.55 or less, the particle size D50 is 200 μm to 600 μm, the pore size at which the cumulative pore volume is 50% of the cumulative pore volume of pores between 5 nm and 300 nm is 75 nm to 160 nm, the primary particle size of at least one of the silica binder and the zirconia binder is 10 nm to 150 nm, and the cumulative pore area of ​​pores between 5 nm and 300 nm is 10.0 m² / g to 35.0 m². A molded article having a concentration of less than or equal to / g, and in which the ratio of the cumulative pore volume of pores with a diameter of 5 nm to 10 nm to the cumulative pore volume of pores with a diameter of 5 nm to 300 nm is 0.1 volume% to 5.0 volume%.

2. The molded article according to claim 1, wherein the zeolite is at least one of zeolites with cationic type: Na (sodium) and cationic type: H (proton).

3. The molded article according to claim 1 or 2, wherein the zeolite is a zeolite having one or more skeletal structures selected from the group consisting of FER structure, HEU structure, YFI structure, MAZ structure, CHA structure, and MOR structure.

4. The molar ratio of silica to alumina in the zeolite (SiO ２ / Al ２ O ３ The molded article according to claim 1 or 2, wherein the ratio is 3 or more and 100 or less.

5. A method for potassium adsorption comprising the step of contacting a molded body according to claim 1 or 2 with a solution containing potassium ions.

6. A column comprising the molded body according to claim 1 or 2.

7. A potassium adsorption system comprising the column described in claim 6.

Images