Method and apparatus for analyzing and recovering metal impurities

Abstract

To safely analyze metal impurities in a flammable organic solvent without increasing the cost.SOLUTION: A method for analyzing metal impurities in an organic solvent having flammability includes a step of passing an organic solvent as a sample liquid through an adsorbent 11 to capture metal impurities in the sample liquid by the adsorbent 11, and a step of measuring a liquid passage amount of the sample liquid to the adsorbent 11, in which the step of measuring the liquid passage amount includes guiding the sample liquid so as to flow through a non-hazardous area, and measuring and integrating a flow rate of the sample liquid in a non-contact manner in the non-hazardous area.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for analyzing metal impurities and a recovery device. [Background technology]

[0002] Highly purified organic solvents are used in the manufacturing processes of electronic devices such as semiconductors. Metal impurities contained in organic solvents, even in trace amounts, can have a significant impact on device characteristics, so strict control of their concentrations is required. This requires highly accurate analysis of trace amounts of metal impurities in organic solvents. In particular, there is a need for highly accurate analysis even when the metal impurity concentrations in organic solvents are so low that they are below the detection limit of analytical instruments such as inductively coupled plasma mass spectrometry (ICP-MS).

[0003] To analyze such low concentrations of metal impurities, a known method involves heating and concentrating a sample liquid sampled in a bottle to increase the metal impurity concentration. However, this method involves the risk of contamination during the process of sampling and concentrating the sample liquid, and there is also a limit to the concentration rate achieved by heating. In contrast, Patent Document 1 proposes a method for analyzing metal impurities using a concentration method using an ion exchanger. In this method, an organic solvent is first passed through an ion exchanger, such as a monolithic organic porous ion exchanger, to capture the metal impurities in the sample liquid. Next, an eluent is passed through the ion exchanger, and the captured metal impurities are eluted and recovered. The metal impurities in the recovered eluent are then quantified, and the metal impurity concentration in the sample liquid is calculated from the resulting metal concentration. This method eliminates the need to sample the sample liquid in a bottle, thereby reducing the risk of contamination and increasing the concentration efficiency compared to methods that involve heating and concentrating the sample liquid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2024-042940 Summary of the Invention [Problem to be solved by the invention]

[0005] While the method described in Patent Document 1 has the above-mentioned advantages, it also has the disadvantage of increasing costs when the sample solution is a flammable organic solvent. Specifically, the method described in Patent Document 1 requires measuring the total flow rate of the sample solution passing through the ion exchanger in order to calculate the metal impurity concentration in the sample solution. However, explosion-proof measures may be required for the measuring equipment as stipulated by law. However, such explosion-proof equipment is expensive, which increases the cost of the equipment.

[0006] Therefore, an object of the present invention is to safely analyze metal impurities in flammable organic solvents without increasing costs. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the method for analyzing metal impurities of the present invention is a method for analyzing metal impurities in a flammable organic solvent, and includes the steps of passing the organic solvent as a sample liquid through an adsorbent and capturing the metal impurities in the sample liquid in the adsorbent, and measuring the amount of sample liquid passing through the adsorbent, wherein the step of measuring the amount of liquid passing includes guiding the sample liquid so that it flows through a non-hazardous location, and measuring and integrating the flow rate of the sample liquid in the non-hazardous location in a non-hazardous location.

[0008] In addition, the metal impurity recovery device of the present invention is a recovery device that recovers metal impurities in an organic solvent in order to analyze the metal impurities in a flammable organic solvent, and includes a sample liquid line through which the organic solvent is circulated as a sample liquid, an adsorbent provided in the sample liquid line for capturing metal impurities in the sample liquid, a housing that accommodates a portion of the sample liquid line including the adsorbent, and a measurement unit that is externally attached to the sample liquid line outside the housing and that non-contactly measures the flow rate of the sample liquid flowing through the sample liquid line.

[0009] According to such a method for analyzing metal impurities and a recovery device, the total flow rate of the sample liquid passing through the adsorbent can be determined without using expensive equipment that complies with explosion-proof specifications. [Effects of the Invention]

[0010] As described above, according to the present invention, metal impurities in flammable organic solvents can be analyzed safely without increasing costs. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram of an impurity recovery unit according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components common to the following embodiments will be denoted by the same reference numerals in the drawings, and redundant descriptions will be omitted where appropriate.

[0013] 1 is a schematic diagram of an impurity recovery unit according to one embodiment of the present invention. Note that the configuration of the impurity recovery unit shown in the figure is merely an example, and it goes without saying that it can be modified as needed, for example, by adding valves or measuring instruments.

[0014] The impurity recovery unit 10 recovers metal impurities from an organic solvent supplied to a point of use through a solvent supply line (not shown). The organic solvent to be recovered is not particularly limited as long as it is flammable, and examples thereof include various organic solvents such as alcohols (isopropyl alcohol, methanol, ethanol, etc.), ketones (cyclohexanone, methyl isobutyl ketone, acetone, methyl ethyl ketone, etc.), alkenes (2,4-diphenyl-4-methyl-1-pentene, 2-phenyl-1-propene, etc.), esters (propylene glycol monomethyl ether acetate, isopropyl acetate, etc.), aromatics, and amines (N-methylpyrrolidone, etc.), as well as mixtures thereof.

[0015] The impurity recovery unit 10 has a sampling line L1 and a concentration column 11 attached to the sampling line L1. A portion of the sampling line L1, including the concentration column 11, is housed in a housing 12. The components of the impurity recovery unit 10, which will be described later, are also housed in the housing 12 unless otherwise specified. The sampling line (sample liquid line) L1 is connected upstream to a solvent supply line (not shown) and has the function of extracting and circulating a portion of the organic solvent flowing through the solvent supply line as a sample liquid. The concentration column 11 is composed of a resin container and an ion exchanger (adsorbent) filled in the container, and has the function of capturing and concentrating metal impurities in the sample liquid supplied through the sampling line L1. Although not shown, a drain pan is provided at the bottom of the housing 12 for recovering the sample liquid in the event of a leak inside the housing 12.

[0016] Examples of ion exchangers packed into the concentration column 11 include ion exchange resins, ion adsorption membranes (porous membranes with ion exchange capacity), and monolithic organic porous ion exchangers. Among these, monolithic organic porous ion exchangers are preferred. Monolithic organic porous ion exchangers are monolithic organic porous materials, i.e., porous materials formed from organic polymers with numerous interconnected pores serving as flow paths for the reaction solution. Compared to typical granular ion exchange resins, monolithic organic porous ion exchangers enable liquid flow at higher spatial velocities, significantly shortening the required time. Furthermore, monolithic organic porous ion exchangers are advantageous in that the captured metal impurities are easily eluted in the eluent used for quantitative analysis, thereby reducing the amount of eluent used and thereby reducing the amount of sample liquid flow. Depending on the type of metal element to be captured, at least one of monolithic organic porous cation exchangers and monolithic organic porous anion exchangers can be used as the monolithic organic porous ion exchanger. Specific examples of monolithic organic porous ion exchangers will be described later.

[0017] An on-off valve V1 is provided in the sampling line L1 upstream of the concentration column 11, and a replacement water supply line L2 equipped with an on-off valve V2 is connected downstream of the on-off valve V1. An on-off valve V3 is provided in the sampling line L1 downstream of the concentration column 11, and a replacement water discharge line L3 equipped with an on-off valve V4 is connected upstream of the on-off valve V3. The replacement water supply line L2 is connected upstream to a replacement water supply source (not shown) provided outside the housing 12, and together with the replacement water discharge line L3, is provided to supply replacement water to the concentration column 11 and circulate it. A purification means for removing metal impurities from the replacement water supplied to the concentration column 11 may be provided downstream of the on-off valve V2 in the replacement water supply line L2. For example, an ion exchanger similar to that packed in the concentration column 11 can be used as such a purification means.

[0018] A replacement gas supply line L4 equipped with an on-off valve V5 is connected to the sampling line L1 downstream of the concentration column 11 (specifically, upstream of the connection with the replacement water discharge line L3). Furthermore, a fluid discharge line L5 equipped with an on-off valve V6 is connected to the sampling line L1 upstream of the concentration column 11 (specifically, downstream of the connection with the replacement water supply line L2). The replacement gas supply line L4 is connected to a replacement gas supply source (not shown) provided outside the housing 12 on its upstream side, and is provided together with the fluid discharge line L5 to supply and circulate the replacement gas to the concentration column 11.

[0019] An eluent tank 13 for storing an eluent is provided inside the housing 12. The eluent tank 13 is connected to a replacement gas supply line L4 (specifically, upstream of the on-off valve V5) via a gas pressurization line L6 equipped with an on-off valve V7. The gas pressurization line L6 is provided to supply replacement gas from the replacement gas supply line L4 to the eluent tank 13 to pressurize it and discharge the eluent from the eluent tank 13. The eluent tank 13 is also connected to the sampling line L1 (specifically, downstream of the connection with the replacement water discharge line L3 and upstream of the on-off valve V3) via an eluent supply line L7 equipped with an on-off valve V8. The eluent supply line L7, together with the fluid discharge line L5, is provided to supply the eluent from the eluent tank 13 to the concentration column 11 and circulate it.

[0020] As will be described in detail later, to calculate the content of metal impurities in the sample liquid, it is necessary to grasp (measure) the total amount of sample liquid passing through the concentration column 11. To this end, the impurity recovery unit 10 has an integrating flow meter (measurement unit) 14 provided in the sampling line L1. The integrating flow meter 14 is preferably a non-contact type that measures the flow rate of the sample liquid without contact, and specifically, a clamp-on ultrasonic flow meter that can be attached to the outside of the piping that constitutes the sampling line L1. Therefore, the integrating flow meter 14 can be installed at any position on the sampling line L1, and in this embodiment, it is provided downstream of the concentration column 11 and outside the housing 12. A specific example of the integrating flow meter 14 is the clamp-on flow sensor "FD-X series" manufactured by Keyence Corporation. Note that, although a non-contact optical flow meter may be used as the integrating flow meter 14, a clamp-on ultrasonic flow meter is preferred from the viewpoint of detection sensitivity. In addition, instead of the integrating flow meter 14, a combination of an instantaneous flow meter and a calculation device that integrates its measurement values ​​may be used, but in this case too, it is preferable that the instantaneous flow meter be a clamp-on type ultrasonic flow meter.

[0021] Here, we will explain a method for recovering metal impurities in an organic solvent using the above-mentioned impurity recovery unit 10, and a method for analyzing the recovered metal impurities. Note that the metal impurities referred to here include not only those in the form of ions or particulates, but also those present in the form of compounds or complexes.

[0022] First, an organic solvent is passed through the concentration column 11 as a sample liquid. Specifically, by opening the on-off valves V1 and V3 of the sampling line L1, a part of the organic solvent flowing through the solvent supply line (not shown) is passed through the concentration column 11 as a sample liquid. In this way, metal impurities in the sample liquid are captured and concentrated by the ion exchanger in the concentration column 11. The passing speed at this time is not particularly limited, but is preferably 2000 h in space velocity (SV). -1 It is preferable that it is less than 1000h -1 It is more preferable that it is less than 200h. -1It is particularly preferable that the linear velocity (LV) is 1000 m / h or less, and more preferably 500 m / h or less. The liquid passing time (concentration time) at this time depends on the type of ion exchanger packed in the concentration column 11 and the liquid passing speed described above, but is not particularly limited as long as the metal impurities to be analyzed are concentrated to a degree that allows them to be quantified with sufficient accuracy. Note that, in order to calculate the content of metal impurities in the sample liquid from the results of the quantitative analysis described below, the total liquid passing volume of the sample liquid through the concentration column 11 is required, and this total liquid passing volume is measured at this time by the integrating flow meter 14. Thereafter, after a predetermined liquid passing time has elapsed, the on-off valves V1 and V3 of the sampling line L1 are closed to stop the passage of the sample liquid through the concentration column 11.

[0023] The sample liquid may be passed through the concentration column 11 in a downward flow direction, as opposed to the illustrated example. However, it is known that when the sample liquid is passed through the concentration column 11, the solubility of the gas in the organic solvent changes due to mixing with the water contained in the ion exchanger, and the dissolved gas in the sample liquid is generated as bubbles. Therefore, it is preferable that the sample liquid be passed through the concentration column 11 in an upward flow direction, as illustrated, to facilitate the escape of such bubbles.

[0024] Next, a substitution process is performed by flowing replacement water and replacement gas through the concentration column 11 in this order. Specifically, first, the on-off valves V2 and V6 of the replacement water supply line L2 and the fluid discharge line L5 are opened. After a certain amount of replacement water supplied from the replacement water supply line L2 is discharged to the outside through the fluid discharge line L5, the on-off valve V6 of the fluid discharge line L5 is closed and the on-off valve V4 of the replacement water discharge line L3 is opened. This allows replacement water to flow through the concentration column 11, replacing the sample liquid remaining in the concentration column 11, particularly the ion exchanger, with the replacement water. The replaced sample liquid is then discharged to the outside together with the replacement water through the replacement water discharge line L3. Once the content of the concentration column 11 has been sufficiently replaced with replacement water, the on-off valves V2 and V4 of the replacement water supply line L2 and the replacement water discharge line L3 are closed to stop the flow of replacement water through the concentration column 11, and the on-off valves V5 and V6 of the replacement gas supply line L4 and the fluid discharge line L5 are opened. As a result, the replacement gas is passed through the concentration column 11, and the replacement water remaining in the concentration column 11, particularly in the ion exchanger, is further replaced with the replacement gas. The replaced replacement water is discharged to the outside together with the replacement gas through the fluid discharge line L5. This replacement process prevents the eluent (aqueous solution containing an acid) used in the elution process described below from coming into contact with the organic solvent, thereby ensuring safety. Note that it is not necessary to use both replacement water and replacement gas as the replacement fluid for the replacement process; either one may be used.

[0025] The water used as replacement water is preferably as pure as possible, i.e., the metal impurity concentration is preferably reduced as much as possible. Specifically, the metal impurity concentration is preferably reduced to less than 10 ng / L, more preferably less than 1 ng / L, and particularly preferably less than 0.1 ng / L. The gas used as replacement gas is preferably a high-purity gas with a purity of 99.9% or more, more preferably 99.99% or more. The type of high-purity gas is not particularly limited, and examples include inert gases (nitrogen, argon, helium, etc.) and oxygen. Note that air can also be used as the high-purity gas as long as the metal impurities have been sufficiently removed.

[0026] During the flow of the sample liquid, the amount of metal impurities captured by the ion exchanger gradually decreases along the flow direction. Therefore, it is preferable that the flow direction of the replacement fluid is the same as the flow direction of the sample liquid. This allows metal impurities captured by the ion exchanger to be recaptured downstream even after they are desorbed, preventing them from being discharged from the concentration column 11. Therefore, taking into consideration the above-mentioned bubble discharge, it is preferable that the flow direction of the replacement water is upward as shown in the figure. On the other hand, if the replacement gas is passed through the concentration column 11 in an upward flow, bubbling may occur within the concentration column 11, and the replacement water may not be given enough upward force to push it upward. Therefore, although the flow direction of the replacement gas may be upward, the same as the flow direction of the sample liquid, it is more preferable that the flow direction of the replacement gas is downward as shown in the figure from the viewpoint of preventing bubbling. The flow rate of the replacement water is not particularly limited, but is preferably 20,000 h at SV. -1 It is preferable that the temperature is 100 to 4000 h or less. -1 It is more preferable that the LV is 1000 m / h or less, and more preferably 1 to 80 m / h. The time for which the replacement fluid is allowed to flow depends on the type and flow rate of the ion exchanger packed in the concentration column 11, but is not particularly limited as long as the sample liquid remaining in the ion exchanger can be replaced with the replacement fluid.

[0027] Once the inside of the concentration column 11 has been sufficiently purged with the replacement gas, an eluent is passed through the concentration column 11 to perform an elution process. Specifically, the on-off valve V5 of the replacement gas supply line L4 is closed to stop the supply of replacement gas to the concentration column 11, and then the on-off valves V7 and V8 of the gas pressure line L6 and the eluent supply line L7 are opened. Thus, the inside of the eluent tank 13 is pressurized with the replacement gas, and the eluent in the eluent tank 13 is supplied to the concentration column 11 through the eluent supply line L7 and the sampling line L1. Metal impurities captured by the ion exchanger in the concentration column 11 are eluted into the eluent, which is then collected together with the eluent in a collection container (not shown) located downstream of the fluid discharge line L5. The gas used to pressurize the inside of the eluent tank 13 is not limited to the replacement gas used in the replacement process and may be another gas. That is, the gas pressure line L6 may be connected to a supply source of another pressurizing gas instead of being connected to the replacement gas supply line L4. Such pressurizing gases include, for example, inert gases (nitrogen, argon, helium, etc.) and air.

[0028] The eluent used here is an aqueous solution containing an acid. The acid contained in the eluent may be either an inorganic acid or an organic acid, and examples of inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid. Among these, nitric acid, sulfuric acid, and hydrochloric acid are preferred because they facilitate the elution of ionic metal impurities and enable the preparation of high-purity eluents. The acid concentration in the eluent is not particularly limited, but is preferably 0.1 to 3.0 N. Furthermore, the eluent is preferably one in which the concentration of each metal impurity is 100 ng / L or less. Specifically, nitric acid or hydrochloric acid in which the concentration of each metal impurity is 100 ng / L or less is more preferred, and nitric acid or hydrochloric acid in which the concentration of each metal impurity is 10 ng / L or less is particularly preferred.

[0029] The amount of eluent passed through is not particularly limited as long as the concentration of metal impurities in the recovered eluent is higher than the detection limit of an analytical device described below, but as described below, it is preferably as small as possible. Note that the amount of eluent passed through (recovered amount) is necessary to calculate the content of metal impurities in the sample liquid, just like the total amount of sample liquid passed through the concentration column 11, and is therefore measured during the elution process, for example, by an integrating flow meter provided in the fluid discharge line L5 (specifically, outside the housing 12), or is measured by a recovery container with a measuring function.

[0030] The metal impurities in the recovered eluent are then quantified, and the metal impurity concentrations in the sample solution are calculated from the obtained metal concentrations. For example, an inductively coupled plasma mass spectrometer (ICP-MS), an inductively coupled plasma atomic emission spectrometer (ICP-AES), an atomic absorption spectrometer, or an ion chromatograph can be used to quantify the metal impurities. The type of metal impurity element to be analyzed is not particularly limited, and for example, at least one of Li, B, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Sr, Mo, Ag, Cd, In, Sn, Sb, Ba, W, Au, Pt, and Pb can be analyzed. The metal impurity concentration in the sample solution can be calculated by dividing the obtained metal concentration by the concentration factor of the eluent (the total volume of sample solution passed divided by the volume of eluent recovered). The quantitative analysis described above may be performed on-site where the impurity recovery unit 10 is installed, or may be performed at a location remote from the site.

[0031] According to the above-described calculation method, even if the metal impurity concentration in the organic solvent is so low as to be below the detection limit of the analytical instrument, the metal impurity concentration in the organic solvent can be determined by increasing the concentration factor of the eluent until the metal impurity concentration in the eluent reaches or exceeds the detection limit. Therefore, it is preferable to increase the concentration factor of the eluent as much as possible. Therefore, it is preferable to minimize the amount of eluent recovered for the same total amount of sample liquid passed. In other words, if metal impurities can be recovered with a smaller amount of eluent, it becomes possible to measure (evaluate) even lower concentrations of metal impurities in the organic solvent without increasing the total amount of sample liquid passed. From this perspective, it is preferable that the flow direction of the eluent into the concentration column 11 be opposite to the flow direction of the sample liquid, as shown in the figure. As described above, the amount of metal impurities captured by the ion exchanger gradually decreases along the flow direction of the sample liquid. However, by passing the eluent in the opposite direction, it becomes possible to recover such metal impurities with a smaller amount of eluent.

[0032] As described above, according to this embodiment, a non-contact flowmeter (e.g., a clamp-on ultrasonic flowmeter) that can be externally attached to the piping that constitutes the sampling line L1 is used as the integrating flowmeter 14 that measures the total amount of sample liquid passing through the concentration column 11. Therefore, the integrating flowmeter 14 can be installed outside the housing 12, which is a non-hazardous location, rather than inside the housing 12, which is a hazardous location. This eliminates the need for expensive explosion-proof equipment. Naturally, there is no need to employ a complex explosion-proof structure or undergo certification procedures for explosion-proof standards. Furthermore, the use of an external integrating flowmeter 14 not only eliminates the need for piping work, but also eliminates the need for leakage prevention measures. As a result, it is possible to analyze metal impurities in flammable organic solvents without increasing costs. The hazardous location referred to here is a location where an explosive atmosphere exists or is likely to exist due to the leakage of flammable gas or vapor from a flammable liquid into the atmosphere, and where the use of equipment that complies with specified explosion-proof standards is mandatory. The location of the integrating flow meter 14 is not particularly limited as long as it is outside the housing 12, and may be, for example, upstream of the concentration column 11.

[0033] In the above-described recovery method, as long as the steps up to the substitution treatment with replacement water can be performed on-site (at the installation location of the impurity recovery unit 10), the remaining steps may be performed elsewhere. For example, the impurity recovery unit 10 may be portable and not include the eluent tank 13 and the associated lines L6 and L7. In this case, the steps up to the substitution treatment with replacement water may be performed on-site, and then the impurity recovery unit 10 including the housing 12 may be transported to another location, where the remaining steps may be performed. Alternatively, the substitution treatment with replacement gas may be performed at that other location, and then the impurity recovery unit 10 may be transported to a further other location, where the elution treatment may be performed. Alternatively, instead of the impurity recovery unit 10 being portable, the concentration column 11 may be removably attached to the sampling line L1. In this case, too, the steps up to the substitution treatment with replacement water may be performed on-site, and then the concentration column 11 may be removed from the sampling line L1, and the remaining steps may be performed elsewhere. Alternatively, the substitution treatment with replacement gas may be performed at that other location, and then the elution treatment may be performed at yet another location. For this purpose, the concentration column 11 may be provided with a sealing means for sealing the inside to prevent contamination or leakage when the concentration column 11 is removed from the sampling line L1.

[0034] Here, two types of monolithic organic porous ion exchangers will be described as specific examples of monolithic organic porous ion exchangers suitable for use as adsorbents packed in the concentration column 11. One is a first monolithic organic porous ion exchanger described in paragraphs

[0019] to

[0028] of Japanese Patent Application Laid-Open No. 2010-234357, and the other is a second monolithic organic porous ion exchanger described in paragraphs

[0052] to

[0061] of the same publication. Hereinafter, the monolithic organic porous ion exchanger will be simply referred to as a "monolith ion exchanger," and the monolithic organic porous material will also be simply referred to as a "monolith." Furthermore, a monolithic organic porous intermediate, which is an intermediate (precursor) in the production of a monolith, will also be simply referred to as a "monolith intermediate."

[0035] The first monolith ion exchanger is obtained by introducing ion exchange groups into a monolith, and has a continuous macropore structure in which bubble-like macropores overlap each other, and these overlapping portions form openings (mesopores) with an average diameter of 30 to 300 μm, preferably 30 to 200 μm, and particularly preferably 35 to 150 μm, when wetted with water.

[0036] The method for producing a first monolithic ion exchanger, as described in paragraphs

[0029] to

[0051] of Japanese Patent Publication No. 2010-234357, consists of the following four steps: (1) First, a mixture of an oil-soluble monomer containing no ion exchange groups, a surfactant, and water is stirred to prepare a water-in-oil emulsion. The water-in-oil emulsion is then polymerized to obtain a first monolith intermediate with a continuous macropore structure and a total pore volume of 5 to 16 ml / g. (2) A mixture is prepared consisting of a vinyl monomer, a crosslinker having at least two vinyl groups per molecule, an organic solvent that dissolves the vinyl monomer and the crosslinker but not the polymer produced by polymerization of the vinyl monomer, and a polymerization initiator. (3) This mixture is allowed to stand and polymerized in the presence of the first monolith intermediate obtained in (1) above to obtain a first monolith with a thicker skeleton than the first monolith intermediate. (4) Then, ion exchange groups are introduced into the first monolith thus obtained to produce a first monolith ion exchanger.

[0037] The second monolithic ion exchanger is a bicontinuous structure consisting of a three-dimensionally continuous skeleton with a thickness of 1 to 60 μm, which is made of an aromatic vinyl polymer containing 0.3 to 5.0 mol% of crosslinked structural units among all structural units to which ion-exchange groups have been introduced, and three-dimensionally continuous pores with a diameter of 10 to 100 μm between the skeletons. The second monolithic ion exchanger has a total pore volume of 0.5 to 5 ml / g and an ion exchange capacity per volume in a water-wet state of 0.3 to 5 mg equivalents / ml, and the ion-exchange groups are uniformly distributed throughout the porous ion exchanger.

[0038] The second monolith ion exchanger is manufactured through the following four steps, as described in paragraphs

[0062] to

[0083] of Japanese Patent Application Laid-Open No. 2010-234357. (1) First, a mixture of an oil-soluble monomer containing no ion exchange groups, a surfactant, and water is stirred to prepare a water-in-oil emulsion. The water-in-oil emulsion is then polymerized to obtain a second monolith intermediate with a continuous macropore structure and a total pore volume of more than 16 ml / g and not more than 30 ml / g. (2) A mixture is prepared containing an aromatic vinyl monomer, a crosslinker having at least two vinyl groups per molecule and 0.3 to 5 mol% of the total oil-soluble monomer, an organic solvent that dissolves the aromatic vinyl monomer and the crosslinker but not the polymer produced by polymerization of the aromatic vinyl monomer, and a polymerization initiator. (3) This mixture is allowed to stand and polymerized in the presence of the second monolith intermediate obtained in (1) above to obtain a second monolith with a bicontinuous structure. (4) Then, ion exchange groups are introduced into the second monolith thus obtained to produce a second monolith ion exchanger. [Explanation of symbols]

[0039] 10 Impurity recovery unit 11 Concentration column 12. Case 13 Eluent tank 14. Integrating flow meter (measurement section) L1 Sampling line (sample liquid line) L2 Replacement water supply line L3 Displacement water discharge line L4 Replacement gas supply line L5 Fluid discharge line L6 Gas pressure line L7 Eluent supply line V1~V8 on-off valves

Claims

1. A method for analyzing metal impurities in a flammable organic solvent, comprising: a step of passing the organic solvent as a sample solution through an adsorbent and capturing the metal impurities in the sample solution on the adsorbent; measuring the amount of the sample liquid passing through the adsorbent; The step of measuring the amount of liquid passed directing the sample liquid to flow through a non-hazardous location; and measuring and integrating the flow rate of the sample liquid in a non-hazardous location without contact.

2. 2. The analytical method according to claim 1, wherein the flow rate of the sample liquid is measured using a clamp-on ultrasonic flowmeter.

3. a step of flowing at least one of water and gas as a replacement fluid through the adsorbent after the sample liquid has been passed through, thereby replacing the sample liquid remaining in the adsorbent with the replacement fluid; the step of passing an eluent through the adsorbent after the replacement fluid has been passed through, and eluting the metal impurities captured by the adsorbent into the eluent and recovering them.

4. Quantifying the recovered metal impurities; The analytical method according to claim 3 , further comprising: calculating a concentration of the metal impurities in the organic solvent based on the result of the quantification and the acquired amount of the solution passed.

5. 3. The analytical method according to claim 1, wherein the adsorbent is a monolithic organic porous ion exchanger.

6. The analytical method according to claim 1 or 2, wherein the organic solvent is an alcohol.

7. 1. A recovery apparatus for recovering metal impurities in a flammable organic solvent in order to analyze the metal impurities in the organic solvent, comprising: a sample liquid line through which the organic solvent is passed as a sample liquid; an adsorbent provided in the sample liquid line for capturing the metal impurities in the sample liquid; a housing that accommodates a portion of the sample liquid line including the adsorbent; a measuring unit that is attached to the outside of the housing and to a pipe that constitutes the sample liquid line, and that measures the flow rate of the sample liquid flowing through the sample liquid line in a non-contact manner.

Images