阅读说明：本技术 过滤器、金属离子去除方法和金属离子去除设备 (Filter, metal ion removing method, and metal ion removing apparatus ) 是由 小林光明 冈田幸久 白井贵章 冈田秀幸 于 2019-01-03 设计创作，主要内容包括：本发明提供了一种过滤器,所述过滤器包括多孔模塑件,所述多孔模塑件为含有干燥凝胶粉末的混合粉末的烧结制品,所述干燥凝胶粉末包括离子交换树脂和热塑性树脂粉末,或所述烧结制品的溶胀主体。当使电阻率值为18MΩ·cm或更大的水通过1200hr-1的空间速度时,水通过之后的所述电阻率值为15MΩcm或更大。本发明提供了一种过滤器,所述过滤器可有效地去除待处理溶液中的金属离子,并且易于获取具有极低金属离子含量的溶液。(The present invention provides a filter comprising a porous molded member which is a sintered product containing a mixed powder of a dry gel powder comprising an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered product. When water having a resistivity value of 18 M.OMEGA.cm or more is passed through a space velocity of 1200hr-1, the resistivity value after the passage of water is 15 M.OMEGA.cm or more. The present invention provides a filter which can effectively remove metal ions in a solution to be treated and easily obtain a solution having an extremely low content of metal ions.)

1. A filter comprising a porous molded member which is a sintered product of a mixed powder containing a dry gel powder comprising an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered product, and

when water having a resistivity value of 18 M.OMEGA.cm or more is passed through the filter at a space velocity of 1200hr-1, the resistivity value after the water is passed through is 15 M.OMEGA.cm or more.

2. A method for removing metal ions in a solution to be treated, the method comprising a passing step of passing the solution to be treated through the filter according to claim 1.

3. The removal method according to claim 2, wherein:

the passing step includes:

a first passing step of passing the solution to be treated through a first filter; and

a second passing step of passing the solution to be treated having passed the first passing step through a second filter, and

the second filter is the filter of claim 1.

4. The removing method according to claim 3, wherein the first filter includes a porous molding which is a sintered article containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

5. A method for removing metal ions from a solution to be treated containing a compound having an acidic group, the method comprising:

an addition step of adding a strong base to the solution to be treated; and

a passing step of treating the solution with the added strong base to pass through the filter of claim 1.

6. The removal method according to claim 5, wherein the compound having the acidic group includes at least one type selected from the group consisting of: phenol resins, acrylic resins, epoxy resins, silicone resins, and monomers as raw materials for these resins.

7. The removal method according to claim 5 or 6, wherein an equivalent ratio of the strong base to the acidic group in the solution to be treated is 1.0 × 10^-9Or greater and 1.0 × 10^-4Or smaller.

8. The removal method according to any one of claims 5 to 7, wherein:

the passing step includes:

a first passing step of passing the solution to be treated through a first filter; and

a second passing step of passing the solution to be treated having passed the first passing step through a second filter, and

the second filter is the filter of claim 1.

9. The removing method according to claim 8, wherein the first filter includes a porous molding which is a sintered article containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

10. The removal method according to claim 9, wherein:

the ion exchange resin in the second filter includes sulfonic acid groups, and

the ion exchange resin in the first filter includes at least one type of group selected from the group consisting of a phosphoramidate group, an iminodiacetic acid group, and a tertiary amino group.

11. A metal ion removal apparatus, comprising:

a first filter; and

a second filter for removing metal ions from the solution to be treated which has passed through the first filter, and

the second filter is the filter of claim 1.

12. The metal ion removal apparatus of claim 11, wherein the first filter comprises a porous molding that is a sintered article containing a mixed powder of a dry gel powder comprising an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

13. The metal ion removal apparatus of claim 12, wherein

The ion exchange resin in the second filter includes sulfonic acid groups, and

the ion exchange resin in the first filter includes at least one type of group selected from the group consisting of a phosphoramidate group, an iminodiacetic acid group, and a tertiary amino group.

Technical Field

The invention relates to a filter, a metal ion removing method and a metal ion removing apparatus.

Background

Solutions with low metal ion content have long been needed as solutions for the manufacture of electronic components such as integrated circuits. For example, patent document 1 describes an apparatus for reducing the metal content in a surfactant to a ppb level sufficient for use in a high-performance semiconductor material.

Disclosure of Invention

Recently, electronic components have become increasingly dense. As line widths decrease with densification, even small amounts of impurities can adversely affect electronic components. For this reason, in order to ensure stability, the allowable content of metal ions in a solution for manufacturing electronic parts is required to be sufficiently low. For example, it is contemplated that metal ions are removed to levels below ppb levels. However, according to the conventional method, it may be difficult to appropriately reduce the content of metal ions, or many processing processes may result in low efficiency.

The object of the present invention is to provide a filter which can effectively remove metal ions in a solution to be treated and which is easy to obtain a solution having an extremely low content of metal ions. It is another object of the present invention to provide a metal ion removing method and a metal ion removing apparatus using the filter.

Means for solving the problems

One aspect of the present invention relates to a filter comprising a porous molded member which is a sintered product containing a mixed powder of a dry gel powder comprising an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered product. When water having a resistivity value of 18 M.OMEGA.cm or more is passed through the filter at a space velocity of 1200hr-1, the resistivity value after the water is passed through is 15 M.OMEGA.cm or more.

Another aspect of the present invention relates to a method for removing metal ions in a solution to be treated, and the method includes a passing step of passing the solution to be treated through the above-described filter.

In one aspect, the passing step may include a first passing step of passing the solution to be treated through a first filter, and a second passing step of passing the solution to be treated through the first passing step through a second filter. Here, the second filter may be a filter according to the above aspect of the present invention.

In view of the above, the first filter may include a porous molded member that is a sintered article containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

Still another aspect of the present invention relates to a method for removing metal ions from a solution to be treated containing a compound having an acidic group. According to the above aspect of the present invention, the removing method includes an adding step of adding a strong base to the solution to be treated, and a passing step of passing the solution to be treated containing the added strong base through a filter.

In one aspect, the compound having an acidic group may include at least one type selected from the group consisting of: phenol resins, acrylic resins, epoxy resins, silicone resins, and monomers as raw materials for these resins.

In one aspect, the equivalent ratio of strong base to acidic groups in the solution to be treated can be 1.0 × 10^-9Or greater and 1.0 × 10^-4Or smaller.

In one aspect, the passing step may include a first passing step of passing the solution to be treated through a first filter, and a second passing step of passing the solution to be treated through the first passing step through a second filter. Here, the second filter may be a filter according to the above aspect of the present invention.

In view of the above, the first filter may include a porous molded member that is a sintered article containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

In view of the above, the ion exchange resin in the second filter may include sulfonic acid groups, and the ion exchange resin in the first filter may include at least one type of group selected from the group consisting of a phosphoramidate group, an iminodiacetic acid group, and a tertiary amino group.

Another aspect of the present invention relates to a metal ion removing apparatus including a first filter and a second filter for removing metal ions from a solution to be treated that has passed through the first filter, and the second filter is a filter according to the above aspect of the present invention.

From one aspect, the first filter may include a porous molded article which is a sintered article containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

In view of the above, the ion exchange resin in the second filter may include sulfonic acid groups, and the ion exchange resin in the first filter may include at least one type of group selected from the group consisting of a phosphoramidate group, an iminodiacetic acid group, and a tertiary amino group.

Effects of the invention

The present invention provides a filter which can remove metal ions in a solution to be treated, thereby easily obtaining a solution having an extremely low metal ion content. The invention also provides a metal ion removing method and a metal ion removing device using the filter.

Drawings

Fig. 1 is a view illustrating a metal ion removing apparatus according to an embodiment;

FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1; and is

Fig. 3 is a view illustrating a metal ion removing apparatus according to another embodiment.

Detailed Description

Further, preferred embodiments of the present embodiment will be described below with reference to the accompanying drawings. Parts are modified to draw the drawings for ease of understanding, and the dimensional ratios and the like are not limited to those shown in the drawings.

Filter

The filter according to this embodiment includes a porous molded member which is a sintered article containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

The filter according to this embodiment is characterized in that when water having a resistivity value of 18 M.OMEGA.cm or more is passed through the filter at a space velocity of 1200hr-1, the resistivity value after the passage of the water is 15 M.OMEGA.cm or more. The resistivity value before water passage is required to be 18M Ω · cm or more, and may be about 18.23M Ω · cm, which is a theoretical threshold. The upper limit of the resistivity value after the water passes through is not particularly limited, and may be, for example, the resistivity value before the water passes through or less.

In the present specification, the resistivity value of water is measured by an in-line resistance sensor ERF-001-C-T manufactured by Horiba, Inc.

The filter can remove metal ions in the solution to be treated, thereby easily obtaining a solution having an extremely low content of metal ions from the solution to be treated containing metal ions.

In this embodiment, the sintered article may have self-supporting strength, and the thermoplastic resin powder may fix the dry gel powder. In this embodiment, since the thermoplastic resin powder fixes the dried gel powder in the sintered article, the self-supporting strength is maintained even if the size is changed due to the swelling of the dried gel powder. That is, the porous molded article may have a self-supporting strength in the sintered article or the swollen body.

In the case of a conventional adsorbent using a gel material, the gel material may absorb water, thereby causing a large dimensional change and a large decrease in strength. For this purpose, generally, the gel material has been held in a support body or molded into beads. Instead, the filter according to this embodiment may be a self-supporting filter as described above. In this case, metal ions can be removed efficiently while achieving space saving.

In this embodiment, the dried gel powder need only absorb water and become swollen to assume the gel shape. For example, a dry gel powder may be obtained by drying hydrogel particles.

The dry gel powder includes an ion exchange resin. The ion exchange resin may be a resin having an ion exchange group or a chelating group. Examples of ion exchange groups include sulfonic acid groups, carboxylic acid groups, tertiary amino groups, and quaternary ammonium groups. Examples of the tertiary amino group include dialkylamino groups (groups represented by — NR12 (R1 independently represents a substituted or unsubstituted alkyl group)), more specifically, dimethylamino groups and diethylamino groups. Examples of the quaternary ammonium group include trialkylammonium groups (groups represented by-N + R23 (R2 independently represents a substituted or unsubstituted alkyl group)), more specifically, trimethylammonium groups, dimethylethylammonium groups, and dimethylhydroxyethylammonium groups. Examples of chelate groups include polyamines, phosphoramidate groups, iminodiacetate groups, urea groups, thiol groups, and dithiocarbamate groups.

The ion exchange resin may be a resin such as polystyrene, acryl resin, polyvinyl alcohol, cellulose, and polyamide, and these resins may be modified to have the above-mentioned ion exchange group or chelating group, and may be crosslinked by a crosslinking agent such as divinylbenzene.

The dry gel powder may contain an ion exchange resin as a main component. The main component described herein means a component in an amount of 50% by weight or more (preferably 80% by weight or more, more preferably 90% by weight or more).

The dry gel powder may also contain inorganic materials. Examples of the inorganic material include silica gel, alumina gel, and smectite. These inorganic materials may be modified to have the above-mentioned ion exchange group or chelating group.

The percentage of water absorption of the dried gel powder is preferably 30% by weight or more, and more preferably 40% by weight or more. Therefore, even if the solution to be treated contains a small amount of moisture, the moisture can be effectively removed to more effectively remove the metal ions. The percentage of water absorption of the dried gel powder is preferably 90% by weight or less, more preferably 60% by weight or less. This tends to further increase the strength of the porous molded article.

In this specification, the percentage of water absorption of the dried gel powder is obtained according to the loss on drying method in accordance with JIS K7209: 2000. More specifically, the weight of the swollen gel formed by swelling the dried gel powder with a sufficient amount of water was measured (W1). Subsequently, the swollen gel was dried in an oven (DRM620DB, manufactured by davit (Tokyo kyo, Tokyo) (advontec (Bunkyo-ku, Tokyo)) at 105 ℃ for 24 hours or more, and the dry weight was measured (W2). Then, the water absorption percentage was obtained according to the formula (I) mentioned below.

Percent (%) water absorption (W1-W2) × 100/W1 (I)

The average particle diameter d1 of the dried gel powder may be, for example, 0.1 μm or more, preferably 1 μm or more. The average particle diameter d1 of the dried gel powder may be, for example, 500 μm or less, preferably 200 μm or less.

For example, a dry gel powder may be obtained by drying hydrogel particles. The drying method is not particularly limited, and examples of the drying method include hot air drying, agitation drying, and vacuum drying.

Preferably, the dry gel powder has a water content percentage of 10 wt% or less. The percentage water content of the dried gel powder is preferably 10% by weight or less, more preferably 5% by weight or less.

In this specification, the percentage of water content of the dried gel powder is obtained according to the loss on drying method. Specifically, the weight of the dried gel powder (W3) was dried in an oven (DRM620DB, manufactured by pewa (tokyo, wen, kyo)) at 105 ℃ for 24 hours or more, and the dry weight (W4) was measured. Then, the water absorption percentage was obtained according to the formula (II) mentioned below.

Percent (%) water content (W3-W4)/W3 × 100 (II)

In this embodiment, the thermoplastic resin powder is a powder made of a resin material having a thermoplastic resin as a main component, and may be partially fused together to form a porous structure.

The content of the thermosetting resin in the thermosetting resin powder is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 95% by weight or more, with respect to the total amount of the mixed powder.

The thermoplastic resin powder may further include any component other than the thermoplastic resin. Examples of other components include plasticizers such as stearates, talc, silica and antioxidants.

Preferably, the thermoplastic resin powder includes at least one type selected from the group consisting of ultra-high molecular weight polyethylene and polyamide as the thermoplastic resin.

The weight average molecular weight of the ultra-high molecular weight polyethylene is preferably 7.5 × 10⁵g/mol or more and 5 × 10⁷g/mol or less, more preferably 1.0 × 10⁶g/mol or more and 1.2 × 10⁷g/mol or less. The weight average molecular weight of the ultra-high molecular weight polyethylene was measured according to the following method.

"Standard Test Method for Dilute Solution Viscosity of Ethylenepolymsers," D1601, Annual Book of ASTM Standards, American Society for testing and Materials (Standard Test Method for Viscosity of ethylene Polymer Diluent Solution, D1601, "ASTM Annual Standards", American Society for testing and Materials).

"Standard Specification for Ultra-High-Molecular-weight polyethylene Molding and Extrusion Materials," D4020, Annual Book of ASTMstandards, American Society for Testing and Materials (Standard Specifications for Ultra-High Molecular weight polyethylene moldings and extruded Materials, D4020, Annual Standard inspection of ASTM, American Society for Testing and Testing)

The melting point of the ultra-high molecular weight polyethylene is not particularly limited, and may be, for example, in the range of 130 ℃ to 135 ℃. The melt index of the ultra-high molecular weight polyethylene is preferably 1.0g/10min or less (ASTM D1238(ISO1133), 190 ℃, load of 21.6 kg), more preferably 0.5g/10min or less.

Fine particles of semi-crystalline polyamide having a melting point in the range of 150 ℃ to 200 ℃ may be suitably used as the polyamide. Further, the average number of carbon atoms per monomer unit in such polyamide is preferably 10 or more.

The average particle diameter of the thermoplastic resin powder is not particularly limited, and may be, for example, 0.5 μm or more, or 1 μm or more. The thermoplastic resin may have an average particle diameter of, for example, 500 μm or less, or 100 μm or less. The gaps of the porous molded member tend to be increased by increasing the average particle diameter of the thermoplastic resin to facilitate passage, and the porous molded member tends to be densified by decreasing the average particle diameter of the thermoplastic resin to improve strength.

Preferably, the thermoplastic resin powder is a non-spherical resin powder. For example, the thermoplastic resin powder may have a shape in which small spherical particles are aggregated together like a bunch of grapes, or a plurality of protrusions are formed on spherical particles such as pointed candy balls. Non-spherical thermoplastic resin powders tend to have improved resistance to dimensional changes upon swelling.

Preferably, the thermoplastic resin powder is a porous powder. The bulk density of the porous thermoplastic resin powder may be, for example, in the range of 0.1 to 0.7g/cm3, or in the range of 0.2 to 0.6g/cm 3. In the present specification, the bulk density of the porous thermoplastic resin powder is measured according to a method in compliance with ISO 60.

In this embodiment, the ratio d2/d1 of the average particle diameter d2 of the dried gel powder to the average particle diameter d1 of the thermoplastic resin powder is preferably 1.3 or more. The ratio (d3-d2)/d1 of the difference between the average particle diameter d2 of the dried gel powder and the average particle diameter d3 of the dried gel powder swollen by absorbing water to the average particle diameter d1 of the thermoplastic resin powder is preferably 4.0 or less. This can further improve the strength of the porous molded article, which is more suitably used as a self-supporting filter.

The average particle diameter D1 of the thermoplastic resin powder represents a value of D50, which is obtained according to the laser diffraction/scattering method in conformity with JISZ8825: 2013. More specifically, for the thermoplastic resin powder, a particle size distribution was obtained according to a laser diffraction/scattering method using a Mastersizer 3000 manufactured by Malvern (the u.k., Worcester) and D50, which resulted in a particle number of 50%, was defined as an average particle diameter D1 when integrated from a smaller number.

The average particle diameter d3 of the dried gel powder swollen by absorbing water means the average particle diameter of the swollen gel formed by swelling the dried gel powder with a sufficient amount of water. In this embodiment, the average particle diameter D3 of the swollen gel represents a value of D50, which is obtained according to the laser diffraction/scattering method in accordance with JIS Z8825: 2013. More specifically, for the swollen gel, a particle size distribution was obtained according to the laser diffraction/scattering method using Mastersizer 3000 manufactured by malvern (worsted corporation, uk), and D50, which resulted in 50% of the number of particles when integrated from a smaller number, was defined as an average particle diameter D3.

In this embodiment, the average particle diameter d2 of the dried gel powder is obtained according to the formula (III) mentioned below using the average particle diameter d3 of the swollen gel and the linear expansion coefficient α caused by the water absorption of the dried gel powder.

Average particle diameter d2 ═ average particle diameter d3/(1+ linear expansion coefficient α) (III)

In this embodiment, the linear expansion coefficient α due to the water absorption of the dried gel powder was obtained according to the following method. First, based on the apparent density measured according to the method in conformity with JIS K7365:1999, the volume of the dried gel powder (V1) and the volume of the swollen gel formed by swelling the dried gel powder with a sufficient amount of water (V2) were obtained. The linear expansion coefficient α is obtained using these volumes V1 and V2 according to the formula (IV) mentioned below.

Coefficient of linear expansion α ═ ((V2/V1)1/3-1) (IV)

The ratio d2/d1 of the average particle diameter d2 of the dried gel powder to the average particle diameter d1 of the thermoplastic resin powder is preferably 1.3 or more, more preferably 2 or more. The ratio d2/d1 is preferably 50 or less, more preferably 25 or less. This can prevent the porous molded member from becoming fragile due to dimensional change caused by swelling, thereby easily obtaining a filter having higher strength.

The ratio (d3-d2)/d1 of the difference between the average particle diameter d2 of the dried gel powder and the average particle diameter d3 of the dried gel powder swollen by absorbing water to the average particle diameter d1 of the thermoplastic resin powder is 4.0 or less, preferably 3.0 or less. Further, the ratio (d3-d2)/d1 is preferably 0.2 or more, more preferably 0.3 or more. This can prevent the porous molded member from becoming fragile due to dimensional change caused by swelling, thereby easily obtaining a filter having higher strength.

In this embodiment, the porous molded article is formed by sintering a mixed powder containing a dry gel powder and a thermoplastic resin powder.

From one aspect, the porous molded article can be described as a structure in which the dry gel powder is dispersed and fixed in a porous structure formed by sintering the thermoplastic resin powder. Porous moldings may be described as moldings in which dry gel powder is combined with thermoplastic resin powder.

The content of the dry gel powder in the mixed powder is within the content of 100 parts by mass of the thermoplastic resin powder, preferably 10 parts by mass or more, more preferably 25 parts by mass or more. The content of the dry gel powder in the mixed powder is within the content of 100 parts by mass of the thermoplastic resin powder, preferably 900 parts by mass or less, more preferably 300 parts by mass or less.

The mixed powder may further contain any component other than the dry gel powder and the thermoplastic resin powder as an additive. For example, the mixed powder may also contain activated carbon, heavy metal reduction media, arsenic removal media, antimicrobial media, ion exchange media, iodine, resins, fibers, gas absorption media, and the like. Such additives are contained in an amount of 20% by weight or less, more preferably 5% by weight or less, with respect to the total amount of the mixed powder.

In this embodiment, the mixed powder is filled in a mold according to the desired shape of the porous molded article, and sintered. Sintering of the mixed powder may be performed to fuse the thermoplastic resin powder.

The sintering temperature may be, for example, the melting point of the thermoplastic resin in the thermoplastic resin powder or higher. The sintering temperature may be, for example, 140 ℃ or higher, preferably 150 ℃ or higher. The sintering temperature may be, for example, 200 ℃ or less, or 180 ℃ or less.

The sintering time is not particularly limited, and may be, for example, in the range of 5 minutes to 120 minutes, or in the range of 10 minutes to 60 minutes.

The porous molded article can be molded into various shapes by appropriately selecting a mold into which the mixed powder is filled at the time of sintering. For example, the porous molded part may be molded into various shapes including a disk shape, a hollow cylinder shape, a bell shape, a cone shape, and a hollow star shape.

The thickness of the porous molded member may be, for example, 0.2mm or more, preferably 1mm or more, more preferably 5mm or more. The thickness of the porous molding may be, for example, 1000mm or less, preferably 100mm or less.

The porous molded article may be a sintered article of mixed powders, or a swollen body formed by swelling the sintered article. For example, the sintered article may be swollen with a solvent. Examples of the solvent include water and organic solvents. In this embodiment, the polar solvent that causes swelling of the sintered article is preferably an organic solvent, and is more preferably PGMEA (propylene glycol 1-monomethyl ether 2-acetate), PGME (propylene glycol monomethyl ether), cyclohexane, and ethyl lactate.

The filter according to this embodiment comprises a porous molding. The filter according to this embodiment may be a filter configured by a porous molding, and may also have another member in order to sufficiently remove metal ions.

The shape of the filter according to this embodiment is not particularly limited, and may be, for example, a cylinder, a prism, a plate, a bell, a sphere, a hemisphere, and a rectangular parallelepiped, and they may be hollow.

The filter according to this embodiment is characterized in that, as described above, when water having a resistivity value of 18 M.OMEGA.cm or more is passed through the filter at a space velocity of 1200hr-1, the resistivity value after the passage of the water is 15 M.OMEGA.cm or more.

The method for obtaining such a filter is not particularly limited, and for example, a cleaning liquid is circulated in the porous molded member to clean the porous molded member. Examples of the cleaning liquid include water, organic solvents, acidic solutions, alkaline solutions, and mixed solutions thereof. The cleaning conditions are not particularly limited. For example, the flow rate at the time of cleaning may be in the range of 10mL/min to 10L/min, and the space velocity at the time of cleaning may be in the range of 6hr to 6000 hr-1. The temperature of the cleaning liquid may be in the range of, for example, 1 ℃ to 99 ℃.

Method for removing metal ions

The metal ion removal method according to this embodiment is a method of removing metal ions in a solution to be treated, and has a passing step of passing the solution to be treated through the above-described filter.

According to the removal method according to this embodiment, metal ions (specifically, Na ions, Fe ions, K ions, Ca ions, Co ions, Cr ions, and Ni ions) can be effectively removed, and thus a liquid having an extremely low metal ion content (for example, a liquid having a metal ion content of 500ppt or less per type, more preferably 150ppt or less, and still more preferably 100ppt or less) can be obtained.

In this embodiment, the content of the metal ion in the solution to be treated is not particularly limited. For example, the content of metal ions in the solution to be treated may be 1ppb or more, or 100ppb or more. The upper limit of the content of the metal ion in the solution to be treated is not particularly limited, and may be, for example, 100ppm or less, or 1000ppb or less.

The solution to be treated may be an aqueous solvent such as water, an organic solvent such as PGMEA, or a mixed solution thereof.

The conditions for passing through the solution to be treated are not particularly limited. For example, Space Velocity (SV) may be in the range of 6 to 200 hr-1. The main pressure may be in the range of, for example, 20kPa to 300 kPa.

The solution to be treated may also contain organic compounds. That is, in this embodiment, the metal ions can be removed from the solution formed by dissolving the organic compound in the solvent. In this embodiment, additives may be added to the solution to be treated, and then the metal ions may be removed.

In a preferred aspect, the removal method may be a method of removing metal ions in a solution to be treated containing a compound having an acidic group. Here, according to an embodiment, the removing method may include an adding step of adding a strong base to the solution to be treated, and a passing step of passing the solution to be treated containing the added strong base through a filter.

In view of the above, by performing the addition step, metal ions can be more removed from the solution to be treated containing the compound having an acidic group.

The compound having an acidic group may be a low molecular compound or a high molecular compound. Examples of the acidic group include a phenolic hydroxyl group, a carboxyl group, a sulfone group and a nitric acid group. Of these groups, the phenolic hydroxyl group is most preferred because it works well in the addition step.

For example, the compound having an acidic group may include at least one type selected from the group consisting of: phenol resins, acrylic resins, epoxy resins, silicone resins, and monomers as raw materials for these resins. The compound having an acidic group preferably includes a phenol resin because it functions more significantly in the addition step.

The strong base used in the addition step is not particularly limited. Examples of strong bases include metal hydroxides such as sodium hydroxide and tetramethylammonium hydroxide.

The equivalent ratio of strong base to acidic groups in the solution to be treated is preferably 1.0 × 10^-9Or greater, more preferably 1.0 × 10^-8Or greater, the equivalence ratio is preferably 1.0 × 10^-4Or less, more preferably 1.0 × 10^-5Or smaller. This may further remove metal ions in the pass through step.

In this embodiment, the solution to be treated may be passed through another filter. That is, the passing step may include a first passing step of passing the solution to be treated through a first filter, and a second passing step of passing the solution to be treated that has passed the first passing step through a second filter. Here, the above-described filter is used as the second filter, and the first filter is not particularly limited.

In a preferred aspect, the first filter may include a porous molded member which is a sintered article containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered article.

The first filter according to this aspect may be exemplified by the same filter as the filter according to the above-described embodiment. However, the first filter is not necessarily configured such that when water having a resistivity value of 18 M.OMEGA.cm or more is passed through the filter at a space velocity of 1200hr-1, the resistivity value after the water is passed through is 15 M.OMEGA.cm or more.

From this aspect, it is preferable that the ion exchange resin in the second filter (i.e., the filter according to the above-described embodiment) includes a sulfonic acid group, and the ion exchange resin in the first filter includes at least one type of group selected from the group consisting of a phosphoramidate group, an iminodiacetic acid group, and a tertiary amino group. In such a combination of the first filter and the second filter, for example, even if Na ions elute when the first filter removes Fe ions, the second filter can remove the eluted Na ions, thereby significantly reducing the content of metal ions.

Metal ion removing equipment

The metal ion removal apparatus according to this embodiment includes a removal section having the filter according to the above-described embodiment.

Fig. 1 is a view for describing a metal ion removing apparatus according to a preferred embodiment, and fig. 2 is a sectional view taken along line II-II in fig. 1. The metal ion removal apparatus 100 shown in fig. 1 includes a removal section 10 having a filter 11 according to the above-described embodiment, a first tank 20 for storing a solution 21 to be treated, and a second tank 30 for storing a liquid 31 from which metal ions are removed. The removal section 10 is divided by a filter 11 into a first region 12 and a second region 13.

The first tank 20 is coupled to the removal section 10 via a first line L1, and the solution 21 to be treated in the first tank 20 is sent to the first zone 12 of the removal section 10 through a first line L1. The solution to be treated 21 sent to the first area 12 moves to the second area 13 through the filter 11. At this time, the metal ions in the solution to be treated 21 are removed by the filter 11. The second tank 30 is coupled to the removal section 10 via a second line L2, and the solution to be treated (liquid 31) passing through the filter 11 is sent from the second region 13 to the second tank 30 through a second line L2.

Fig. 3 is a view for describing a metal ion removing apparatus according to another preferred embodiment. The metal ion removing apparatus 200 shown in fig. 3 includes a first removing section 50 having a first filter 51, a second removing section 60 having a second filter 61, a first tank 70 for storing a solution 71 to be treated, a second tank 80 for storing an intermediate liquid 81 passed through the first filter 51, and a third tank 90 for storing a liquid 91 from which metal ions are removed passed through the second filter 61. The second filter 61 is a filter according to the above embodiment.

The first tank 70 is coupled to the first removal section 50 via a first line L11. The solution to be treated 71 in the first tank 70 is sent to the first removal section 50 through a first line L11. The solution to be treated 71 sent to the first removal section 50 is passed through a first filter 51. The first removal section 50 is coupled to the second tank 80 via a second line L12. The intermediate liquid 81 passed through the first filter 51 is sent to the second tank 80 through the second line L12.

The second tank 80 is coupled to the second removal section 60 via a third line L13. The intermediate liquid 81 in the second tank 80 is sent to the second removal section 60 through the third line L13. The intermediate liquid 81 sent to the second removal section 60 is passed through the second filter 61. Second removal section 60 is coupled to third tank 90 via a fourth line L14. The liquid 91 that has passed through the second filter 61 and has been removed of metal ions is sent to the third tank 90 through the fourth line L14.

In a preferred aspect, the first filter 51 may include a porous molded member which is a sintered product containing a mixed powder of a dry gel powder including an ion exchange resin and a thermoplastic resin powder, or a swollen body of the sintered product.

The first filter 51 according to this aspect may be exemplified by the same filter as the filter according to the above-described embodiment. However, the first filter 51 is not necessarily configured such that when water having a resistivity value of 18 M.OMEGA.cm or more is passed through the filter at a space velocity of 1200hr-1, the resistivity value after the water is passed through is 15 M.OMEGA.cm or more.

From this point of view, it is preferable that the ion exchange resin in the second filter 61 (i.e., the filter according to the above-described embodiment) includes a sulfonic acid group, and the ion exchange resin in the first filter 51 includes at least one type of group selected from the group consisting of a phosphoramidate group, an iminodiacetic acid group, and a tertiary amino group. In such a combination of the first filter 51 and the second filter 61, for example, even if the solution to be treated contains a plurality of types of metal ions (for example, iron ions and sodium ions), each type of metal ions can be significantly reduced.

While the description of the preferred embodiments of the present invention has been given above, the present invention is not limited to the above-described embodiments.