Method for manufacturing refined hydrogen peroxide aqueous solution

Abstract

This invention provides a method for manufacturing a hydrogen peroxide aqueous solution, which reduces impurities such as organic matter and prevents foaming and odor. The means to solve the above-mentioned problems is a method for manufacturing a purified hydrogen peroxide aqueous solution, including a predetermined reverse osmosis membrane treatment step in which a crude hydrogen peroxide aqueous solution containing impurities is brought into contact with a reverse osmosis membrane. That is, by adjusting the pressure and linear velocity of the purified hydrogen peroxide aqueous solution in the reverse osmosis membrane treatment step to ensure that the first cumulative value (the product of the reverse osmosis membrane pressure (MPaG) and the linear velocity (m³ / (m²·h)) of the hydrogen peroxide aqueous solution is less than 0.15, the above-mentioned problems are solved.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a purified hydrogen peroxide aqueous solution, and more particularly to a method for manufacturing a purified hydrogen peroxide aqueous solution including a reverse osmosis membrane (RO membrane) treatment step. Prior Technology

[0002] Hydrogen peroxide possesses oxidizing power and strong bleaching and bactericidal properties, thus it is used as a bleaching agent, bactericide, and food additive for paper, pulp, and fibers. Furthermore, its use is increasing in the electronics industry, including for cleaning semiconductor substrates, chemical polishing of copper and tin-containing copper alloys, and etching of electronic circuits. Regarding the manufacturing methods of hydrogen peroxide, the anthraquinone process is the common method. However, the aqueous solution of hydrogen peroxide produced by this method using organic solvents contains impurities such as organic matter from the organic solvents used. Furthermore, during ultrasonic degassing and other processes in the production of aqueous solution of hydrogen peroxide using the anthraquinone process, foaming may occur, and sometimes the characteristic odor of hydrogen peroxide may also be produced. For the reasons mentioned above, hydrogen peroxide aqueous solutions obtained by the anthraquinone process or similar methods are purified. Common methods for purifying hydrogen peroxide aqueous solutions include distillation, cyclone separators, adsorption resins, ion exchange resins, and reverse osmosis membranes (Patent Document 1). [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2000-302418 Summary of the Invention

[0004] [The problem that the invention aims to solve]

[0005] Even with conventional refining methods, it remains possible to obtain an aqueous solution of hydrogen peroxide with satisfactory desired properties. That is, the aqueous solution of hydrogen peroxide obtained by conventional refining methods still contains a relatively large amount of impurities, primarily organic matter, or it cannot adequately suppress foaming and odors generated during degassing.

[0006] A method for manufacturing an aqueous solution of hydrogen peroxide that reduces impurities such as organic matter and does not produce foaming or odor. [Methods for solving problems]

[0007] In order to solve the above-mentioned problems, the inventors of this case have made great efforts to study and found that adjusting the conditions in the treatment step of crude hydrogen peroxide aqueous solution in contacting RO membrane can improve the quality of hydrogen peroxide aqueous solution.

[0008] This invention includes the following. [1] A method for manufacturing a refined hydrogen peroxide aqueous solution, comprising: The reverse osmosis membrane treatment step involves contacting a crude hydrogen peroxide aqueous solution containing impurities with the reverse osmosis membrane; In this reverse osmosis membrane treatment step, the pressure and the linear velocity are adjusted so that the product of the pressure (MPaG) of the reverse osmosis membrane and the linear velocity (m3 / (m2·h)) of the hydrogen peroxide aqueous solution, i.e., the first cumulative value, is less than 0.15. [2] The method for manufacturing refined hydrogen peroxide aqueous solution as described in [1] above, wherein the average surface roughness of the reverse osmosis membrane is 0.24 μm or more. [3] The method for manufacturing refined hydrogen peroxide aqueous solution as described in [1] or [2] above, wherein the average surface roughness of the reverse osmosis membrane is less than 1.0 μm. [4] The method for manufacturing a refined hydrogen peroxide aqueous solution as described in any of [1] to [3] above, wherein the weight ratio of oxygen to nitrogen on the surface of the reverse osmosis membrane is less than 40. [5] The method for producing purified hydrogen peroxide aqueous solution as described in any of [1] to [4] above further has the following advantages: The roughness measurement step measures the surface roughness of the reverse osmosis membrane used in the membrane treatment step. [6] The method for manufacturing a refined hydrogen peroxide aqueous solution as described in any of [1] to [5] above, wherein, in the permeation membrane treatment step, the second cumulative value obtained by multiplying the first cumulative value by the viscosity (mPa·s) value of the crude hydrogen peroxide aqueous solution is less than 0.19. [7] The method for manufacturing a refined hydrogen peroxide aqueous solution as described in any of [1] to [6] above, wherein the temperature of the crude hydrogen peroxide aqueous solution is 10 to 30°C in the permeation membrane treatment step. [8] The method for manufacturing a refined hydrogen peroxide aqueous solution as described in any of [1] to [7] above, wherein the permeation ratio (%) of the permeated hydrogen peroxide water (permeated hydrogen peroxide aqueous solution) and the concentrated hydrogen peroxide water obtained by the permeation membrane treatment step, as defined by the following formula (1), is 80% or less; the permeated hydrogen peroxide water is a hydrogen peroxide aqueous solution in which the impurities have been reduced, and the concentrated hydrogen peroxide water is a hydrogen peroxide aqueous solution in which the reverse osmosis membrane has not been permeated and the impurities have been concentrated; Permeation ratio (%) = (mass of water permeated with hydrogen peroxide) / (mass of water permeated with hydrogen peroxide + mass of concentrated hydrogen peroxide) × 100 (1) [9] In the method for manufacturing refined hydrogen peroxide aqueous solution as described in [8] above, the permeation ratio is 40% or less, and the temperature of the crude hydrogen peroxide aqueous solution in the permeation membrane treatment step is 25°C or less.

[10] In the method for manufacturing refined hydrogen peroxide aqueous solution as described in [8] above, the permeation ratio is 60% or more, and the temperature of the crude hydrogen peroxide aqueous solution in the permeation membrane treatment step is 15 to 35°C or less. [Effects of the Invention]

[0009] According to the present invention, an aqueous solution of hydrogen peroxide can be manufactured that can reduce the content of impurities, primarily organic compounds, and suppress foaming and odor, which may occur mainly during the manufacturing process of hydrogen peroxide. Simple Explanation of the Diagram

[0010] [Figure 1] is a schematic diagram of one state of the hydrogen peroxide purification system used in the method for manufacturing purified hydrogen peroxide aqueous solution of the present invention. [Figure 2] is a graph showing the relationship between the product of the pressure of the RO membrane and the linear velocity of the hydrogen peroxide water during the purification process (first product) and the amount of organic matter (TC value) in the purified hydrogen peroxide water in the results of the examples and comparative examples. [Figure 3] is a graph showing the relationship between the pressure of the RO membrane during purification, the product of the linear velocity of hydrogen peroxide water and the viscosity of hydrogen peroxide water (second product), and the amount of organic matter (TC value) in the purified hydrogen peroxide water in the results of the examples and comparative examples. Implementation

[0011] One aspect of this invention is a method for manufacturing a refined hydrogen peroxide aqueous solution, comprising: a reverse osmosis membrane treatment step, in which a crude hydrogen peroxide aqueous solution containing impurities is brought into contact with a reverse osmosis membrane. The method for manufacturing a refined hydrogen peroxide aqueous solution involves adjusting the pressure and linear velocity in the reverse osmosis membrane treatment step to ensure that the product of the reverse osmosis membrane pressure (MPaG) and the linear velocity of the hydrogen peroxide aqueous solution (m³ / (m²·h)) is less than 0.15. By employing this method for manufacturing a refined hydrogen peroxide aqueous solution, a hydrogen peroxide aqueous solution with reduced impurities, such as foaming, odor, and organic compounds, that are primarily generated during the hydrogen peroxide manufacturing process, can be obtained. The method for manufacturing the refined hydrogen peroxide aqueous solution of the present invention will be described in more detail below.

[0012] [Method for manufacturing refined hydrogen peroxide aqueous solution] A method for producing a purified hydrogen peroxide aqueous solution includes a permeate membrane treatment step for purifying a crude hydrogen peroxide aqueous solution. In this permeate membrane treatment step, a reverse osmosis membrane (RO membrane) is used to obtain a purified hydrogen peroxide aqueous solution with fewer impurities such as organic compounds compared to the crude hydrogen peroxide aqueous solution. In other words, the crude hydrogen peroxide aqueous solution is purified in the permeate membrane treatment step to produce a purified hydrogen peroxide aqueous solution with fewer impurities.

[0013] 1. Membrane treatment steps 1-1. Relationship between pressure of reverse osmosis membrane and linear velocity of crude hydrogen peroxide aqueous solution In the permeate membrane treatment step, the crude hydrogen peroxide aqueous solution is purified. Crude hydrogen peroxide aqueous solution refers to hydrogen peroxide aqueous solution that has not been purified by an RO membrane. The hydrogen peroxide aqueous solution can be obtained by any method, including the anthraquinone process, alcohol oxidation process, redox process, direct process (direct oxidation process), electrolysis process, etc. Crude hydrogen peroxide aqueous solution may also contain any or both organic and inorganic impurities. The concentration of hydrogen peroxide in the crude hydrogen peroxide aqueous solution is not particularly limited, and can be, for example, 20-90% by weight, 30-80% by weight, 35-70% by weight, 40-60% by weight, etc. In the reverse osmosis membrane treatment step, the pressure of the reverse osmosis membrane and the linear velocity of the hydrogen peroxide aqueous solution are adjusted within a preferred range. Specifically, the pressure and linear velocity are adjusted such that the product of the reverse osmosis membrane pressure (MPaG) and the linear velocity of the hydrogen peroxide aqueous solution (m³ / (m²·h)) is less than 0.15, i.e., the first cumulative value (MPaG·m³ / (m²·h)). The first cumulative value (MPaG·m³ / (m²·h)) is preferably 0.12 or less, more preferably 0.10 or less, even more preferably 0.08 or less, and particularly preferably 0.06 or less. There is no particular limitation on the lower limit of the first cumulative value (MPaG·m³ / (m²·h)), but it may be, for example, 0.01 or more.

[0014] As mentioned above, by adjusting the range of parameters related to the pressure applied to the reverse osmosis membrane and the linear velocity of the crude hydrogen peroxide aqueous solution during the purification process, namely the range of the first cumulative value, a purified hydrogen peroxide aqueous solution with fewer impurities, primarily organic compounds, can be obtained.

[0015] In the membrane permeate treatment step, the first cumulative value mentioned above is further multiplied by the viscosity (cP or mPa·s) of the crude hydrogen peroxide aqueous solution to obtain a second cumulative value (MPaG·m 3 / (m 2·h)·cP; or MPaG·m 3·cP / (m 2·h) or (MPaG·m 3 / (m 2·h)·mPa·s), which is preferably less than 0.19. The second cumulative value (MPaG·m 3 / (m 2·h)·mPa·s) is preferably 0.17 or less, more preferably 0.15 or less, more preferably 0.13 or less, and especially preferably 0.10 or less. Furthermore, there is no particular limitation on the lower limit of the second cumulative value (MPaG·m 3 / (m 2·h)·mPa·s), but it is, for example, 0.01 or more.

[0016] As mentioned above, by adjusting and applying the pressure value to the reverse osmosis membrane, the linear velocity value of the crude hydrogen peroxide aqueous solution being processed, and the viscosity value of the crude hydrogen peroxide aqueous solution, i.e., the range of the second cumulative value, a refined hydrogen peroxide aqueous solution with fewer impurities can be obtained during the purification process of the crude hydrogen peroxide aqueous solution.

[0017] The pressure (gauge pressure: MPaG) required for purifying the crude hydrogen peroxide aqueous solution in the reverse osmosis membrane treatment step, that is, the pressure (MPaG) applied to the crude hydrogen peroxide aqueous solution to be passed through the reverse osmosis membrane, is preferably 0.02~8.0, more preferably 0.10~6.5, even more preferably 0.30~5.5, and may also be 0.40~4.7, 0.80~4.5, 1.0~4.0, etc. Furthermore, the indicated pressure (MPaG) value in the permeate membrane treatment step is equivalent to the value obtained by subtracting 0.1 from the absolute pressure (MPaA (or MPa)). Therefore, the absolute pressure (MPaA (or MPa)) value can be converted by adding 0.1 to the indicated pressure (MPaG) value. For example, the preferred range of pressure for the aforementioned reverse osmosis membrane, based on the pressure value specified by the gauge, is preferably 0.12 to 8.1 in absolute pressure (MPaA (or MPa)), more preferably 0.20 to 6.6, even more preferably 0.40 to 5.6, and may also be 0.50 to 4.5, 0.90 to 4.6, 1.1 to 4.1, etc.

[0018] The linear velocity (m³ / (m²·h)) of the crude hydrogen peroxide aqueous solution in the permeate membrane treatment step should preferably be 0.005~0.050, more preferably 0.007~0.040, and even more preferably 0.010~0.030.

[0019] The flow rate (L / min) of the crude hydrogen peroxide aqueous solution in the permeate membrane treatment step should preferably be 0.03~3.0, more preferably 0.1~2.5, even more preferably 0.3~2.0, and especially preferably 0.5~1.5. Furthermore, in the permeate treatment step, it is advisable to use a reverse osmosis membrane with a pure water permeate flow rate that can be adjusted to less than 0.6 (m³ / m² / day) under conditions of 25°C and 2.0 MPa, as detailed below.

[0020] The viscosity (cP or mPa·s) of the crude hydrogen peroxide aqueous solution in the permeate membrane treatment step should preferably be 0.05~3.0, more preferably 0.1~2.7, even more preferably 0.3~2.5, and particularly preferably 0.5~2.0 or 0.9~1.5.

[0021] 1-2. Temperature of crude hydrogen peroxide aqueous solution In the membrane permeate treatment step, the temperature of the crude hydrogen peroxide aqueous solution to be treated is, for example, -20~40℃, preferably 5~25℃, but other temperature ranges are also possible. For example, the temperature range of the crude hydrogen peroxide aqueous solution to be treated can also be 10~30℃, 12~27℃, 15~25℃, etc.

[0022] Furthermore, in the permeate membrane treatment step, the range of the value (MPaG / ℃) obtained by dividing the pressure (MPaG) applied to the crude hydrogen peroxide aqueous solution by the temperature (℃) of the crude hydrogen peroxide aqueous solution is preferably 0.01~0.50, more preferably 0.03~0.40, even more preferably 0.05~0.35, and particularly preferably 0.10~0.30.

[0023] 1-3. Permeability Ratio The permeation ratio (permeate ratio; %) of the mass ratio of permeate water to concentrated hydrogen peroxide water obtained by the permeate membrane treatment step, as defined by the following formula (1), should preferably be 80% or less, or 85% or less or 90% or less; the permeate water is a hydrogen peroxide aqueous solution with reduced impurities, and the concentrated hydrogen peroxide water is a hydrogen peroxide aqueous solution that has not permeated the reverse osmosis membrane and whose impurities have been concentrated. Permeation ratio (%) = (mass of water permeated with hydrogen peroxide) / (mass of water permeated with hydrogen peroxide + mass of concentrated hydrogen peroxide) × 100 (1) The aforementioned permeation ratio is preferably 75% or less, more preferably 70% or less, and especially preferably 60% or less. Furthermore, the permeation ratio can be, for example, 20% or more, preferably 25% or more, or 35% or more. If the permeation ratio is high, a large amount of permeate-treated hydrogen peroxide water can be obtained in a short time through the membrane treatment step; however, the workload of the devices in the purification system described later for purifying the hydrogen peroxide water solution will also increase, so it is advisable to keep it within the aforementioned predetermined range.

[0024] Considering the efficient removal of organic compounds, it is recognized that in the permeate membrane treatment step, when the permeate ratio is low, it is better to lower the temperature of the hydrogen peroxide aqueous solution of the target substance. Therefore, for example, it is advisable to set the permeate ratio of the above formula (1) to 40% or less, 35% or less, or 30% or less, and set the temperature of the crude hydrogen peroxide aqueous solution in the permeate membrane treatment step, that is, the liquid temperature, to 25°C or less or 20°C or less, for example, to 5~25°C or 10~20°C, etc. On the other hand, it has been found that in the permeate membrane treatment step, when the permeate ratio is high, it is preferable even if the temperature of the hydrogen peroxide aqueous solution of the object being treated is relatively high. Therefore, for example, it is preferable to set the permeate ratio of the above formula (1) to 60% or more, 65% or more, or 70% or more, and to set the temperature of the crude hydrogen peroxide aqueous solution in the permeate membrane treatment step, i.e., the liquid temperature, to be within the range of 15~35℃ or 10~30℃.

[0025] 1-4. Impurities contained in crude hydrogen peroxide aqueous solution A purified hydrogen peroxide aqueous solution, obtained through a permeation membrane treatment step, is a hydrogen peroxide aqueous solution with reduced impurities, known as permeate hydrogen peroxide water. However, the impurity concentration in the permeate hydrogen peroxide water should preferably be below 20 mg / L. According to the method for producing purified hydrogen peroxide aqueous solution of the present invention, substantially impurity-free permeate hydrogen peroxide water can be efficiently generated, and the impurity concentration can be reduced as described above. The impurity concentration in the permeate hydrogen peroxide water is preferably below 16 mg / L, more preferably below 12 mg / L, particularly preferably below 10 mg / L, or below 8 mg / L.

[0026] Impurities in crude hydrogen peroxide aqueous solutions, which are the targets of refining, typically contain organic compounds generated during hydrogen peroxide production steps, such as the anthraquinone process. Examples of such organic compounds include, for instance, the components of the working solution and their deterioration products in a crude hydrogen peroxide aqueous solution obtained using the anthraquinone process. Examples of deterioration products include: non-polar solvent deterioration products (e.g., benzaldehyde, benzoic acid, phenol, benzyl alcohol, etc.), polar solvent deterioration products (e.g., 2-ethylhexanol, 2-ethylhexanal, etc.), and anthraquinone deterioration products (e.g., anthrone, oxyanthrone, tetrahydrooxyanthrone, anthraquinone epoxide, tetrahydroanthrone epoxide, etc.).

[0027] Furthermore, the crude hydrogen peroxide aqueous solution sometimes contains inorganic compounds as impurities. Examples of inorganic impurities include compounds derived from the catalyst in the anthraquinone process, such as copper, zinc, chromium, palladium, rhodium, ruthenium, platinum, iron, nickel, aluminum, sodium, potassium, calcium, chlorine, sulfur, silicon dioxide, and boron. These inorganic compounds may also be the target of refining.

[0028] 2. Reverse osmosis membrane (RO membrane) 2-1. Morphology of Reverse Osmosis Membranes The type of reverse osmosis membrane used in the permeate membrane treatment step is not particularly limited, as long as it has the ability to remove impurities contained in the crude hydrogen peroxide aqueous solution. In terms of the form of reverse osmosis membranes, flat sheet membranes, pleated membranes, spiral membranes, tubular membranes, rod membranes, capillary membranes, spaghetti membranes, hollow fiber membranes, or combinations thereof can be listed. In the permeate treatment step, a reverse osmosis membrane device incorporating a reverse osmosis membrane can be used, such as a cylindrical device with a built-in reverse osmosis membrane of the various shapes described above. A reverse osmosis membrane device can be used individually, or multiple devices can be connected in series or parallel. For example, two or more reverse osmosis membrane devices can be connected in parallel, or more than ten reverse osmosis membrane devices can be used.

[0029] 2-2. Materials for Reverse Osmosis Membranes Examples of materials used for reverse osmosis membranes include polyethyleneimine condensates, cellulose acetate, modified polyacrylonitrile, polybenzimidazole piperazine, polyetheramide, cellulose triacetate, polyamide carboxylic acid, cross-linked polyether, cross-linked polyamide, polyamide, polybenzimidazole, sulfonated phenyl ether, polypiperamide, polyethyleneimine, toluene diisocyanate, polyethyleneimine chloroethylene, sulfonated polyfurfuryl alcohol, sulfonated polyurethane, polyether urea, polyvinyl alcohol, polyurethane, polyamide-polyvinyl alcohol, sulfonated polyether urea, or polyamide. Reverse osmosis membranes can be asymmetric or composite membranes. Composite membranes made of polyamide are preferred.

[0030] As a material for reverse osmosis membranes, it is preferable to use materials with an oxygen / nitrogen mass ratio of less than 40. That is, the aforementioned ratio of the weight of oxygen atoms to nitrogen atoms in the material components that form the surface of the reverse osmosis membrane that is permeable by hydrogen peroxide aqueous solution should preferably be less than 40, more preferably less than 35, more preferably less than 25, less than 20 or less than 10, and especially preferably less than 2, for example, 0.1 or more and less than 2.

[0031] Previously, RO membranes with high oxygen / nitrogen ratios, such as those coated with polyvinyl alcohol (PVA), were sometimes thought to suppress the adhesion of organic impurities. However, PVA can also decompose due to hydrogen peroxide. Therefore, considering the need to avoid unnecessary decomposition on the membrane surface, it is advisable to use RO membranes without PVA coating or RO membranes that meet the aforementioned oxygen / nitrogen ratio requirements.

[0032] 2-3. Properties of reverse osmosis membranes The average surface roughness of the reverse osmosis membrane should preferably be 0.240 μm or more. Furthermore, the average surface roughness of the reverse osmosis membrane should preferably be 1.000 μm or less. When using a reverse osmosis membrane with such an average roughness value, it has been confirmed that the TC rejection rate of the hydrogen peroxide-permeable water increases, that is, the TC value of the hydrogen peroxide-permeable water is effectively reduced. The average surface roughness of the reverse osmosis membrane is preferably 0.300 μm to 0.900 μm, more preferably 0.400 μm to 0.850 μm, and even better if it is 0.450 μm to 0.800 μm, such as 0.500 μm to 0.750 μm. Typically, the initial surface roughness of the RO membrane is often 0.600 to 0.700 μm, but it is believed that the surface tends to smooth out and decrease in roughness due to use. Therefore, confirming and adjusting the average roughness value of the reverse osmosis membrane is important. Furthermore, the surface roughness value of the reverse osmosis membrane is based on the arithmetic mean roughness Ra value of JIS specification (JIS B 0601-2001).

[0033] When contacting the crude hydrogen peroxide aqueous solution with the reverse osmosis membrane, the appropriate treatment pressure for the reverse osmosis membrane is as long as it is within the allowable range of the reverse osmosis membrane. The reverse osmosis membrane should preferably be able to withstand a pressure of 0.02 to 8.0 MPaG applied to the crude hydrogen peroxide aqueous solution. The pressure range that can be applied to the reverse osmosis membrane is preferably the pressure range mentioned above in the osmosis membrane treatment step, or 0.10 to 7.0 MPaG, more preferably 0.30 to 6.0 MPaG, 0.50 to 5.0 MPaG, and for example 1.0 to 4.5 MPaG. Furthermore, the allowable pressure (absolute pressure: MPaA (or MPa)) of the reverse osmosis membrane should preferably be 0.12~8.1 (MPaG), more preferably 0.20~7.1 (MPa), even more preferably 0.40~6.1 (MPa), 0.60~5.1 (MPa), and for example 1.1~4.6 (MPa).

[0034] The reverse osmosis membrane should preferably be one that allows the permeate flow rate of pure water to be adjusted to less than 0.6 (m³ / m² / day) at a temperature of 25°C and an effective pressure of 2.0 MPa. Specifically, it is preferable to use a membrane that can allow pure water to permeate at a permeate flow rate of 0.1 or higher but less than 0.6 (m³ / m² / day), 0.2 or higher but less than 0.6 (m³ / m² / day), or 0.3 or higher but less than 0.5 (m³ / m² / day). Furthermore, the temperatures mentioned above refer to the temperatures of the pure water permeating the reverse osmosis membrane and the reverse osmosis membrane itself. Also, the effective pressure refers to the effective pressure acting on the reverse osmosis membrane obtained by subtracting the osmotic pressure difference and secondary side pressure from the average operating pressure. The average operating pressure is the average of the pressure of the supply water (operating pressure) and the pressure of the concentrate (concentrate outlet pressure) on the primary side of the reverse osmosis membrane (i.e., the value of (operating pressure + concentrate outlet pressure) / 2). As a reverse osmosis membrane, it is advisable to use one with a permeability of 300~1000 GPD (gallons per day) under the conditions of feed water temperature of 25℃, supply pressure of 5.5MPa and salt concentration of 32000 (ppm (mg / L)) in the supply water. The better permeability of the reverse osmosis membrane is 400~800 GPD, more preferably 500~700 GPD, and even better is 550~650 GPD.

[0035] Furthermore, RO membranes can be incorporated into reverse osmosis membrane modules. A reverse osmosis membrane module can include a reverse osmosis membrane, a pressure vessel for fixing and supporting the reverse osmosis membrane, and may also include a pressurization method to bring crude hydrogen peroxide aqueous solution into contact with the reverse osmosis membrane.

[0036] There is no particular limitation on the membrane area of ​​the reverse osmosis membrane, that is, the area of ​​the permeate surface of the crude hydrogen peroxide aqueous solution of the reverse osmosis membrane. For example, the membrane area of ​​the reverse osmosis membrane contained in each solid equipment-sized device (about 8 inches in length, etc.) is about 40 m2.

[0037] 3. Roughness Measurement Procedure The method for manufacturing purified hydrogen peroxide aqueous solution shall preferably include a roughness measurement step, which measures the surface roughness of the reverse osmosis membrane used in the permeate membrane treatment step. As mentioned above, the surface roughness value of the RO membrane usually decreases with use in the permeate membrane treatment step, so the roughness measurement step is to confirm whether the average surface roughness has been adjusted to the aforementioned preferred range. The surface roughness value of the reverse osmosis membrane should preferably be measured before or after the osmosis membrane treatment step, for example, before the osmosis membrane treatment step, or at least confirmed by data. Furthermore, it is preferable to measure the surface roughness value of the reverse osmosis membrane immediately after the osmosis membrane treatment step, as this provides clear insights into the deterioration of the reverse osmosis membrane during the treatment, the relationship between the crude aqueous solution, the impurity concentration (TC value) in the hydrogen peroxide permeate, and the surface roughness value. Therefore, measuring the surface roughness value of the reverse osmosis membrane after the osmosis membrane treatment step can predict the subsequent replacement period of the reverse osmosis membrane and prevent adverse conditions from occurring in advance during the osmosis membrane treatment step. The surface roughness value of the RO membrane was measured using a three-dimensional white light interferometer and an atomic force microscope (AFM).

[0038] [Refining System for Hydrogen Peroxide Aqueous Solution] Figure 1 is a schematic diagram of an example of a hydrogen peroxide aqueous solution purification system 10 that can be used in the permeate membrane treatment step of purifying hydrogen peroxide aqueous solution. The purification system 10 includes an RO membrane container 3, etc., in which an RO membrane 3a is installed. In the purification system 10, the raw material hydrogen peroxide (crude hydrogen peroxide aqueous solution, hereinafter also referred to as crude aqueous solution) storage tank 1, metering pump 2, RO membrane container 3, back pressure valve 4, first and second flow sensors 6a and 6b, and purification side and non-purification side treatment liquid storage tanks 8a and 8b are connected by piping as shown in the figure. The crude aqueous solution, as described below, is separated into permeate (permeate hydrogen peroxide water) which is sent to the purification side treatment liquid storage tank 8a and concentrate (concentrated hydrogen peroxide water) which is sent to the non-purification side treatment liquid storage tank 8b by an RO membrane 3a disposed inside the RO membrane container 3, and then purified.

[0039] In the purification process of the hydrogen peroxide aqueous solution using the purification system 10, firstly, a predetermined raw material aqueous solution is added to the raw material aqueous solution storage tank 1, and the liquid temperature is adjusted using a cooler / heater to reach a predetermined temperature (e.g., the temperature listed in the table below showing the results of the example (20°C, etc.)). The raw material aqueous solution is pumped to the RO membrane container 3 using a metering pump 2, and after confirming that hydrogen peroxide is flowing into the concentrate side piping, the back pressure valve 4 connected to the concentrate side piping is gradually closed to pressurize the inside of the RO membrane container 3 to a predetermined pressure (e.g., the pressure listed in the table below showing the results of the example (2.20 MPaG, etc.)). Furthermore, if the osmotic pressure of the crude aqueous solution inside the RO membrane container 3 exceeds the predetermined pressure, hydrogen peroxide will begin to flow into the permeate side piping.

[0040] In practice, only hydrogen peroxide and water permeate from the RO membrane container 3 to the permeate-side piping, and the crude aqueous solution is purified. On the other hand, hydrogen peroxide water containing impurities is sent from the RO membrane container 3 to the non-permeate-side piping. The permeate ratio, that is, the ratio of the amount of permeate passing through the permeate-side piping to the amount of permeate passing through the non-permeate-side piping, is controlled by adjusting the back pressure valve 4 to achieve a predetermined flow rate by monitoring the flow rates using a first flow sensor 6a located on the permeate-side piping and a second flow sensor 6b located on the non-permeate-side piping. For example, with a feed pump flow rate of 1.00 L / min and a permeate ratio of 50%, the back pressure valve 4 is adjusted to achieve a concentrate (non-permeate): 0.5 L / min and a permeate: 0.5 L / min. In this way, a hydrogen peroxide aqueous solution is collected while maintaining a predetermined permeate / concentrate flow rate ratio.

[0041] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. [Example]

[0042] [Analytical and Measurement Methods] <Applicable processing pressure for reverse osmosis membranes (pressure of reverse osmosis membranes (MPaG))> The pressure (MPaG) of the reverse osmosis membrane was measured using a Bolton tube manometer. Value of linear velocity (m³ / (m²·h)) of hydrogen peroxide aqueous solution Measure the flow rate of the hydrogen peroxide water and the RO membrane area in the following formula (1), and calculate the linear velocity value of the hydrogen peroxide aqueous solution according to the following formula (1). Linear velocity (m³ / (m²·h)) = Flow rate of hydrogen peroxide permeate (m³ / h) / RO membrane area (m²) ･･･(1) <Viscosity (mPa･s) of Crude Aqueous Hydrogen Peroxide Solution> Using a BII viscometer (manufactured by Toki Sangyo Co., Ltd.), measure the viscosity (mPa･s) value of the crude aqueous hydrogen peroxide solution. <TC Value> Use the following device and method to measure the TOC concentration (TC value) representing the amount of organic compounds in the refined aqueous hydrogen peroxide solution. Use a TOC (Total Organic Carbon) meter to measure the TOC value, and thereby obtain the TC value. Device: TOC-L manufactured by Shimadzu Corporation Measurement method: Heat the sample to 680 °C together with a platinum catalyst in a combustion furnace filled with purified air, burn and decompose it, and convert it into carbon dioxide. Cool and dehumidify the obtained carbon dioxide after conversion, and compare it with a calibration curve type to thereby obtain the TC (total carbon) concentration in the sample. Next, acidify the same sample and perform aeration treatment to convert the IC (inorganic carbon) in the sample into carbon dioxide and detect it, thereby obtaining the IC concentration. Subtract the IC concentration from the obtained TC concentration to calculate the TOC concentration.

[0043] <Purification Using RO Membrane> Regarding the RO membrane, a commercially available 582 GPD reverse osmosis membrane was used. Moreover, conditions such as the permeation ratio (collection ratio), supply liquid temperature, supply liquid flow rate, and treatment pressure were set as shown in Table 1 below, and the aqueous hydrogen peroxide solution was purified. <Surface Roughness of RO Membrane> As described below, use a three-dimensional white light interference microscope to measure the surface roughness of the RO membrane. Device: "Contour GT-K" manufactured by Bruker Japan Co., Ltd. Cut each sample of the RO membrane into a square of about 2 cm, place it on the slide of the above device, and supply it for analysis in a water-wetted state. Device: Contour GT-K manufactured by Bruker Measurement mode: Vertical scanning (VSI) Objective lens: 50 times Measurement range: (XY) 126 × 95 μm 2 (Z) 30 μm Reverse scanning: 5 μm Threshold value: 5% (threshold value of the sensitivity of the CCD detector) Calibration: Cylinder + tilt calibration Measurement method: The RO membrane sample was irradiated with white light while the interference fringes were measured by scanning 30 μm in the Z direction. <Effervescence of Hydrogen Peroxide Aqueous Solution> Add 50 ml of purified hydrogen peroxide aqueous solution to a 50 ml volumetric flask and heat in a boiling water bath for 5 hours. Then, cool the aqueous solution to room temperature and visually inspect for foaming when degassing it in an ultrasonic cleaner. No foaming is considered "good"; foaming is considered "bad". <The Odor of Hydrogen Peroxide Aqueous Solution> Measure the purified hydrogen peroxide solution into a 50ml volumetric flask, stopper the flask, and shake it 10 times. Then, judge the odor by the operator's sense of smell. If no odor is detected, it is judged as "good"; if an odor is detected, it is judged as "bad".

[0044] Example 1: The RO membrane was used to purify 45% hydrogen peroxide water (unwashed crude aqueous solution) prepared from hydrogen peroxide obtained using the anthraquinone process under the conditions shown in Table 1 below. For the RO membrane, a commercially available membrane with a membrane area of ​​2.4 (m²), an average surface roughness of 0.60 μm, a pure water permeate flow rate of 0.5 (m³ / m² / day) at a temperature of 25°C and an effective pressure of 2.0 MPa, and an oxygen / nitrogen mass ratio of less than 2 was used. Furthermore, the results of TOC concentration (TC concentration), foaming evaluation, and odor evaluation in the obtained purified hydrogen peroxide aqueous solution (permeate hydrogen peroxide water) are shown in Table 1. [Table 1]

[0045] Examples 2-11 and Comparative Examples 1 and 2: The same 45% hydrogen peroxide water (unwashed crude aqueous solution) as in Example 1 was purified under the conditions described in Table 1 above. For example, in Example 7, to achieve a permeation ratio of 70%, the feed pump flow rate was set to 1.00 L / min, and the back pressure valve 4 was adjusted such that the flow rate of the concentrate (non-permeate) was 0.3 L / min and the flow rate of the permeate was 0.7 L / min. Also in Example 7, to set the linear velocity, i.e., the feed pump flow rate divided by the membrane area, to 0.025 (m³ / (m²·h), the flow rate was set to 1.00 L / min, and an RO membrane with a membrane area of ​​2.4 (m²) was used. Hydrogen peroxide (crude hydrogen peroxide aqueous solution, crude aqueous solution) with a viscosity of 1.17 (mPa·s) was used as the purification target.

[0046] Furthermore, in Examples 8 and 9 and Comparative Example 1, the RO membranes used were of the same type as those used in other examples such as Example 7, and had lower surface roughness values ​​due to prolonged use. The average surface roughness values ​​of the RO membranes are shown in Table 2. [Table 2]

[0047] As can be seen from the results of the examples and comparative examples shown in Table 1, by controlling the purification conditions of the crude aqueous solution, the TC value of the obtained purified hydrogen peroxide water is sufficiently reduced and the occurrence of foaming and odor is suppressed. Specifically, the results in Table 1 and Figure 2 confirm that the example in which the product of the reverse osmosis membrane pressure (MPaG) and the linear velocity (m³ / (m²·h)) of the hydrogen peroxide aqueous solution, i.e., the first cumulative value, is less than 0.15, has sufficiently reduced the TC value. Furthermore, compared to the comparative example that does not meet these requirements, it more effectively removes organic compounds as impurities and prevents foaming and odor. Moreover, the results in Table 1 and Figure 3 show that the example in which the second cumulative value, obtained by further multiplying the first cumulative value by the viscosity (mPa·s) of the crude hydrogen peroxide aqueous solution, is less than 0.19, also achieves effective purification of the crude aqueous solution. Furthermore, the results of Examples 7-9 and Comparative Example 1 shown in Table 2 confirm the following trend: although the purification conditions other than the surface roughness of the RO membrane are not exactly the same (see Table 1), the examples that used RO membranes with a surface roughness of approximately 0.480 μm to 0.600 μm showed that the TC value was sufficiently reduced and good results were observed; in contrast, Comparative Example 1, which used an RO membrane with a surface roughness that was too low, showed a higher TC value and could not sufficiently reduce the concentration of impurities in the hydrogen peroxide permeated water.

[0048] 1: Raw material aqueous solution (crude aqueous solution) storage tank 2: Metering pump 3: RO membrane container 3a:RO membrane 4: Back pressure valve 6a: First flow sensor 6b: Second flow sensor 8a: Refined side treatment fluid storage tank 8b: Unrefined side treatment fluid storage tank 10: Refining System (Refining System for Hydrogen Peroxide Aqueous Solution)

Claims

1. A method for manufacturing a purified hydrogen peroxide aqueous solution, comprising: The reverse osmosis membrane treatment step involves contacting a crude hydrogen peroxide aqueous solution containing impurities with a reverse osmosis membrane. In this membrane treatment step, the pressure and the linear velocity are adjusted such that the product of the pressure (MPaG) of the reverse osmosis membrane and the linear velocity (m3 / (m2·h)) of the hydrogen peroxide aqueous solution, i.e., the first cumulative value, is 0.055 or higher and less than 0.

15. The concentration of hydrogen peroxide in the crude hydrogen peroxide aqueous solution is 45 to 60% by weight.

2. The method for manufacturing purified hydrogen peroxide aqueous solution as claimed in claim 1, wherein, The average surface roughness of the reverse osmosis membrane is above 0.24 μm.

3. A method for producing a purified hydrogen peroxide aqueous solution as described in claim 1 or 2, wherein, The average surface roughness of the reverse osmosis membrane is less than 1.0 μm.

4. A method for producing a purified hydrogen peroxide aqueous solution as described in claim 1 or 2, wherein, The weight ratio of oxygen to nitrogen on the surface of the reverse osmosis membrane is less than 40.

5. The method for manufacturing the purified hydrogen peroxide aqueous solution as claimed in claim 1 or 2 further comprises: a roughness measurement step for measuring the surface roughness of the reverse osmosis membrane used in the permeate membrane treatment step.

6. A method for producing a purified hydrogen peroxide aqueous solution as claimed in claim 1 or 2, wherein, In this permeation membrane treatment step, the first cumulative value is further multiplied by the viscosity (mPa·s) value of the crude hydrogen peroxide aqueous solution to obtain a second cumulative value that is less than 0.

19.

7. A method for producing a purified hydrogen peroxide aqueous solution as claimed in claim 1 or 2, wherein, In this permeate membrane treatment step, the temperature of the crude hydrogen peroxide aqueous solution is 10~30℃.

8. A method for producing a purified hydrogen peroxide aqueous solution as claimed in claim 1 or 2, wherein, The permeation ratio (%) of the permeate water and the concentrated hydrogen peroxide water obtained by the permeate membrane treatment step, as defined by the following formula (1), is 80% or less; the permeate water is a hydrogen peroxide aqueous solution in which the impurities have been reduced, and the concentrated hydrogen peroxide water is a hydrogen peroxide aqueous solution in which the impurities have not permeated the reverse osmosis membrane and have been concentrated; Permeation ratio (%) = (mass of permeate water) / (mass of permeate water + mass of concentrated hydrogen peroxide water) × 100･･･(1).

9. The method for producing purified hydrogen peroxide aqueous solution as described in claim 8, wherein, The permeation ratio is below 40%, and the temperature of the crude hydrogen peroxide aqueous solution in the permeation membrane treatment step is below 25°C.

10. The method for producing purified hydrogen peroxide aqueous solution as claimed in claim 8, wherein, The permeation ratio is above 60%, and the temperature of the crude hydrogen peroxide aqueous solution in the permeation membrane treatment step is below 15~35°C.

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