JP7545817B2 - Device for concentrating and recovering a middle molecule solution and method for operating the same - Google Patents

Description

The present invention relates to a concentration and recovery device for concentrating a solution containing an organic solvent and a method for operating the same.

The forward osmosis membrane is a separation and concentration membrane that utilizes the osmotic pressure difference. Concentration using a forward osmosis membrane proceeds when the liquid to be concentrated comes into contact with a driving liquid having a higher osmotic pressure through the membrane, and the solvent in the liquid to be treated moves to the driving liquid side, driven by the osmotic pressure difference. Forward osmosis membrane technology has the same extremely high blocking properties as reverse osmosis membranes, but can concentrate solutions to high concentrations without applying energy such as heat or pressure, so it is a technology that is expected to be used in fields such as osmotic power generation and food. In addition, forward osmosis membrane technology is expected to be used as a concentration technology for pharmaceutical raw materials that contain components that are easily denatured by heat. A characteristic of the concentration of pharmaceutical raw materials is that the liquid to be treated contains an organic solvent. Generally, forward osmosis membranes are made of polymer materials, so there is a risk of the forward osmosis membrane being deteriorated by organic solvents. If the forward osmosis membrane deteriorates, solutes in the liquid to be treated may flow out into the driving liquid, or solutes in the driving liquid may flow into the liquid to be treated.

Patent document 1 describes how the use of polyketone as the membrane material improves the organic solvent resistance of forward osmosis membranes.

Patent document 2 describes how zeolite, an inorganic material, is used as the membrane material, and the ring structure of the zeolite is controlled to improve organic solvent resistance.

International Publication No. 2016/024573 JP 2014-039915 A

The forward osmosis membrane obtained in Patent Document 1 is not intended to concentrate a liquid containing an organic solvent to a high concentration. In the examples of Patent Document 1, only an example is described in which the liquid to be treated contains a very small amount of organic solvent. In general, there is a difference in the speed at which water and organic solvents permeate the forward osmosis membrane, so the concentration of the organic solvent in the liquid to be treated often increases during the concentration process. Therefore, if a forward osmosis membrane is only resistant to a liquid containing a low concentration of organic solvent, it is difficult to apply the forward osmosis membrane to the concentration of the liquid containing an organic solvent.
The forward osmosis membrane disclosed in Patent Document 2 is impractical as a concentration means because the amount of water permeated is extremely low.
Furthermore, there is no device for concentrating an organic solvent-containing liquid using a forward osmosis membrane made of a polymer or inorganic material that is designed to prevent the outflow of solutes in the treated liquid into the driving liquid after concentration, and at the same time, to prevent the solutes in the driving liquid from mixing into the treated liquid, by using a mechanism of the device.

The problem that the present invention aims to solve is to provide a concentration recovery device and a concentration recovery method that can achieve the desired concentration of a liquid to be treated that contains an organic solvent without deteriorating the forward osmosis membrane when concentrating the liquid to be treated using the forward osmosis membrane.

The inventors focused on the fluctuation in the organic solvent concentration in an organic solvent-containing liquid during concentration using a forward osmosis membrane and came up with the idea of adding a solvent addition mechanism to a concentration and recovery device. They discovered that swelling or dissolution of the forward osmosis membrane can be prevented by controlling the organic solvent concentration of the liquid being treated by adding an appropriate amount of solvent to the liquid being treated during or before concentration. It is expected that controlling the organic solvent concentration will prevent solutes in the liquid being treated from leaking into the driving liquid and/or solutes in the driving liquid from flowing into the liquid being treated.

That is, one example of an embodiment of the present invention is as follows:

[1] An apparatus for concentrating and recovering an organic solvent-containing liquid, comprising:
one or more concentrating mechanisms using a forward osmosis membrane; and a solvent adding mechanism for adding a solvent to the organic solvent-containing liquid.
A concentration recovery device comprising:
[2] The concentration and recovery apparatus according to the above aspect 1, wherein the organic solvent-containing liquid contains medium molecules having a molecular weight of 200 or more and 30,000 or less.
[3] The concentration and recovery apparatus according to the above aspect 1 or 2, wherein the organic solvent-containing liquid contains at least one chemical species selected from the group consisting of amino acids, peptides, nucleic acids, and sugars.
[4] The concentration and recovery apparatus according to any one of aspects 1 to 3, wherein the organic solvent-containing liquid contains at least one solvent selected from the group consisting of water, acetonitrile, methanol, ethanol, isopropyl alcohol, ethyl acetate, hexane, toluene, and dimethyl sulfoxide.
[5] The concentration and recovery apparatus according to any one of aspects 1 to 4, wherein the chemical species constituting the forward osmosis membrane includes at least one selected from the group consisting of polysulfone, polyethersulfone, polyimide, polybenzimidazole, polyvinylidene fluoride, polyacrylonitrile, polyketone, regenerated cellulose, polyamide, polyurea, zeolite, and metal-organic frameworks.
[6] The concentration and recovery apparatus according to any one of Aspects 1 to 5, wherein the driving liquid used in the concentration by the forward osmosis membrane is an aqueous solution containing at least one selected from the group consisting of sodium chloride, magnesium chloride, sodium sulfate, magnesium sulfate, potassium chloride, lithium chloride, lithium bromide, sodium acetate, acetic acid, sodium oxalate, oxalic acid, sodium citrate, citric acid, sodium phosphate, phosphoric acid, and polyethylene glycol.
[7] The concentration and recovery apparatus according to any one of aspects 1 to 6, further comprising a fractionation mechanism using one or more ultrafiltration membranes upstream of the concentration mechanism using the forward osmosis membrane.
[8] The concentration and recovery apparatus according to any one of the above aspects 1 to 7, further comprising a measurement mechanism for observing a solvent composition in an organic solvent-containing liquid.
[9] The concentration and recovery apparatus according to aspect 8, wherein the measurement mechanism is at least one selected from the group consisting of infrared spectroscopy (IR), a measurement method using a refractometer, a measurement method using a density meter, and an analysis method using liquid chromatography / mass spectrometry (LC / MS), a measurement method using gas chromatography / mass spectrometry (GC / MS), ultraviolet-visible spectroscopy (UV-vis), and a nuclear magnetic resonance device (NMR).
[10] A method for operating a concentration and recovery apparatus according to any one of aspects 1 to 9, wherein the organic solvent concentration of the organic solvent-containing liquid does not exceed the upper limit concentration of the forward osmosis membrane used, where the upper limit concentration is defined as follows: the concentration at which the ratio Js/Jw of the water permeation rate (Jw) to the back diffusion rate (Js) of salt is 0.50 when the forward osmosis membrane is immersed in an organic solvent aqueous solution of a certain concentration for 2 hours, the forward osmosis membrane is washed with pure water, and then the forward osmosis membrane is operated with pure water as the treated liquid and a 3.5 mass% aqueous sodium chloride solution as the driving liquid.
[11] The concentration and recovery device according to any one of aspects 1 to 10, further comprising a driving liquid concentration and regeneration mechanism.
[12] The concentration and recovery apparatus according to any one of the above aspects 1 to 11, wherein the concentration and regeneration mechanism is any one of reduced pressure distillation, membrane distillation, and evaporation and concentration using an evaporator.

According to one aspect of the present invention, when a liquid to be treated containing an organic solvent is concentrated using a forward osmosis membrane, it is possible to prevent solutes in the liquid to be treated from flowing out into the driving liquid after concentration and to prevent solutes in the driving liquid from mixing into the liquid to be treated.

1 is a schematic diagram showing a concentration recovery apparatus according to one embodiment of the present invention. 1 is a schematic diagram showing a concentration recovery apparatus according to one embodiment of the present invention. 1 is a schematic diagram showing a concentration recovery apparatus according to one embodiment of the present invention. 1 is a schematic diagram showing a concentration recovery apparatus according to one embodiment of the present invention. 1 is a schematic diagram showing a concentration recovery apparatus according to one embodiment of the present invention. 1 is a schematic diagram showing a concentration recovery apparatus according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing a performance evaluation device for a concentration and recovery device. FIG. 1 shows the results in Example 1. FIG. 13 shows the results in Example 2. FIG. 13 shows the results in Example 3. FIG. 13 shows the results in Example 4. FIG. 13 shows the results in Example 5. FIG. 13 shows the results in Example 6. FIG. 13 shows the results in Example 7. FIG. 13 shows the results in Example 8. FIG. 13 is a diagram showing the results in Comparative Example 1.

The following describes an embodiment of the present invention (hereinafter, referred to as "the present embodiment"). The inventors have focused on the fact that when the organic solvent concentration of the liquid to be treated is sufficiently low, the performance degradation of the forward osmosis membrane is negligible, and that the organic solvent permeates the forward osmosis membrane to a certain extent. One aspect of the present invention provides a solvent addition concentration method in which a solvent is added to the liquid to be treated and concentration is performed using a forward osmosis membrane, and an apparatus for realizing the method.

<Concentration recovery device>
The concentration and recovery apparatus provided by one aspect of the present invention comprises one or more forward osmosis membranes and one or more solvent addition mechanisms, and typically further comprises one or more tanks for treated liquid, one or more drive liquid tanks, and one or more liquid delivery pumps.

Figures 1 to 6 are schematic diagrams showing a concentration recovery device according to one embodiment of the present invention. Referring to Figures 1 to 6, the concentration recovery devices 100, 200, 300, 400, 500, and 600 are equipped with one or more concentration mechanisms using a forward osmosis membrane 4, and a solvent addition mechanism 2 that adds a solvent to an organic solvent-containing liquid. In a typical embodiment, the concentration recovery device is equipped with a tank 1 for treated liquid, a solvent addition mechanism 2, a pump 3, a forward osmosis membrane 4, a driving liquid tank 5, and a measurement mechanism 6. The tank for treated liquid contains an organic solvent-containing liquid. The driving liquid tank contains a driving liquid. In one embodiment, the concentration recovery device further includes an organic solvent-containing liquid supplied to one side of the forward osmosis membrane and a driving liquid supplied to the other side of the forward osmosis membrane.

As shown in FIG. 6, the concentration recovery device according to a specific embodiment may further include a fractionation mechanism using an ultrafiltration membrane 7 and a pretreatment tank 8. The ultrafiltration membrane 7 is preferably provided before the concentration mechanism using the forward osmosis membrane 4 (i.e., upstream of the liquid flow). In the concentration recovery device, the liquid to be treated is stored in a tank 1 for the liquid to be treated and is supplied to the forward osmosis membrane 4 via the ultrafiltration membrane 7 as desired. In a preferred embodiment, the tank 1 for the liquid to be treated is provided between the fractionation mechanism using the ultrafiltration membrane 7 and the concentration mechanism using the forward osmosis membrane 4 as shown in FIG. 6.

There is no limit to the number of forward osmosis membranes 4 that can be installed. Since the desolvation speed of a typical ultrafiltration membrane can differ by nearly 10 times from that of a forward osmosis membrane, it is preferable to provide more forward osmosis membranes than ultrafiltration membranes in the concentration and recovery device, or to provide a tank 1 for the liquid to be treated between the ultrafiltration membrane 7 and the forward osmosis membrane 4 as shown in Figure 6. When multiple forward osmosis membranes are used, the multiple forward osmosis membranes may be connected in parallel (see Figure 4) or in series (see Figure 5). When multiple forward osmosis membranes are used, the same driving liquid may be passed through them, or driving liquids of different types and/or different concentrations may be passed through them.

The driving liquid is stored in the driving liquid tank 5. The driving liquid is sent to the forward osmosis membrane 4 by the pump 3, where the solvent is extracted from the liquid to be treated. As the operation of the driving liquid progresses, the solute concentration of the driving liquid decreases, and the osmotic pressure decreases. Therefore, in a preferred embodiment, it is preferable that the concentration recovery device includes a driving liquid concentration regeneration mechanism (not shown) that extracts the solvent from the diluted driving liquid. It is preferable that the concentration regeneration mechanism is at least one selected from the group consisting of a reduced pressure distillation mechanism, a membrane distillation mechanism, and an evaporation concentration mechanism using an evaporator.

The organic solvent contained in the organic solvent-containing liquid to be treated may affect the desolvation speed of the forward osmosis membrane and the back diffusion of salt, which may result in loss of solutes or deterioration of quality, so the organic solvent concentration in the liquid to be treated must be controlled to be sufficiently low. In this embodiment, the concentration and recovery device is equipped with a solvent addition mechanism 2, which adds a solvent (e.g., water) to the liquid to be treated to maintain the organic solvent concentration of the liquid to be treated at a predetermined level or lower. This solvent addition mechanism is preferably provided after the fractionation mechanism using the ultrafiltration membrane 7 (if used) (i.e., downstream of the liquid flow) and before the forward osmosis membrane 4 (i.e., upstream of the liquid flow).

In one embodiment, an organic solvent concentration monitor serving as a measurement mechanism 6 for measuring the organic solvent concentration in the liquid to be treated is preferably provided within the concentration and recovery device, particularly between the ultrafiltration membrane 7 and the forward osmosis membrane 4. Figures 1 to 6 show an example in which the measurement mechanism 6 is provided within the tank 1 for the liquid to be treated.

<Liquid to be treated>
The liquid to be treated refers to a liquid that is sent to a forward osmosis membrane and concentrated. The liquid to be treated is composed of a solute and a solvent. In this disclosure, a liquid to which a solvent has been added or which has been concentrated is also called the liquid to be treated. The liquid to be treated may be fractionated by an ultrafiltration membrane. In this case, the liquid sent to the ultrafiltration membrane is called a pretreatment liquid, the liquid that has permeated the ultrafiltration membrane is called a permeated liquid, and the liquid that has been blocked by the ultrafiltration membrane is called a blocked liquid.

[solvent]
In the present disclosure, the solvent refers to water and an organic solvent. The organic solvent is an organic compound having one or more carbon atoms, and in one embodiment, is a compound that exists in a liquid state at a temperature higher than 0°C and lower than 50°C at normal pressure. As the organic solvent, for example, one or more selected from the group consisting of acetonitrile, methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate, pentane, hexane, toluene, xylene, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), chloroform, methylene chloride, acetone, and dioxane can be used. More preferably, from the viewpoint of high speed of permeation through the forward osmosis membrane and short concentration time, the solvent is at least one selected from the group consisting of water, acetonitrile, methanol, ethanol, isopropyl alcohol, ethyl acetate, butanol, hexane, toluene, dimethyl sulfoxide, NMP, chloroform, methylene chloride, and acetone, and more preferably at least one selected from the group consisting of water, acetonitrile, methanol, ethanol, isopropyl alcohol, ethyl acetate, hexane, toluene, and dimethyl sulfoxide. The organic solvent-containing liquid of the present disclosure is a liquid containing at least water, an organic solvent, and a solute. The ratio of water to organic solvent is arbitrary, but since the organic solvent can swell or dissolve the forward osmosis membrane and thus deteriorate the performance of the forward osmosis membrane, it is preferable that the concentration of the organic solvent in the organic solvent-containing liquid is equal to or lower than the upper limit concentration of the organic solvent that the forward osmosis membrane can tolerate (also referred to as the allowable upper limit concentration or simply the upper limit concentration in the present disclosure), which will be described later.

[Solute]
In one embodiment, the solute is selected from salts and compounds having a molecular weight of 50 or more. The salt may be an inorganic salt or an organic salt. The solute may be one or more compounds selected from the group consisting of sodium chloride, magnesium chloride, sodium sulfate, magnesium sulfate, potassium chloride, lithium chloride, lithium bromide, sodium acetate, acetic acid, sodium oxalate, oxalic acid, sodium citrate, citric acid, sodium phosphate, and phosphoric acid. Compounds having a molecular weight of 50 or more are not limited, but examples thereof include amino acids, peptides, sugars, nucleic acids, proteins, nucleotides, polyketides, ethylene glycols, aldehydes, carboxylic acids, sulfonic acid compounds, amines, terpenes, aromatic compounds, heterocyclic aromatic compounds, alkaloids, alcohol compounds, ester compounds, and the like.

(Medium molecule)
The medium molecule is an example of the solute and refers to a molecule having a molecular weight of 200 to 30,000. The solute in the liquid to be treated is preferably a medium molecule in terms of solubility in water or organic solvents and the tendency to clog forward osmosis membranes. It is particularly preferable that the medium molecule has a molecular weight of 500 to less than 10,000, 500 to less than 7,000, 500 to less than 3,500, 500 to less than 2,900, or 1,000 to less than 2,900, since it is expected to dissolve in aqueous solutions containing organic solvents of a wide range of concentrations. The molecular weight is a molecular weight calculated from the structural formula, but when the molecular weight exceeds 500, it may be a number average molecular weight calculated in terms of polyethylene oxide using gel permeation chromatography.

In one embodiment, at least one solute selected from the group consisting of amino acids, peptides, nucleic acids, and sugars is preferred. These solutes have many hydrophilic functional groups, such as hydroxyl groups, amino groups, and carboxyl groups, in the molecule, and are more water-soluble than other compounds, such as hydrocarbon compounds, and are therefore less likely to precipitate during the concentration process of the organic solvent-containing liquid, making them preferred.

An amino acid refers to a compound having a carboxy group and an amino group in the same molecule, and includes natural and unnatural amino acids.
Peptides are organic compounds containing one or more amide bonds, and include, but are not limited to, dipeptides such as alanylglutamine, carnosine, anserine, and aspartame; oligopeptides such as glutathione; hormone peptides such as insulin; and cyclic peptides such as cyclosporin A and bacitracin.
A nucleic acid may be a molecule consisting of five monosaccharides, a nucleobase, and a phosphate.
The saccharide may be an organic compound containing one or more of a hexasaccharide backbone, a pentasaccharide backbone, and a glucosamine backbone, and examples thereof include, but are not limited to, sugar chains such as oligosaccharides, oligosaccharide peptides, and oligosaccharides.

The organic solvent-containing liquid may contain one or more of an acid, a buffer, impurities having a molecular weight larger than the above-mentioned medium molecule, etc., but may not contain these. The acid is preferably at least one selected from the group consisting of acetic acid, fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, hydrochloric acid, sulfuric acid, citric acid, and oxalic acid. The buffer may be at least one selected from the group consisting of acetic acid, oxalic acid, citric acid, phosphoric acid, boric acid, tartaric acid, and alkali metal salts thereof (e.g., sodium salts), and Tris buffer.

<Driving fluid>
The driving liquid is an aqueous solution having a higher osmotic pressure than the liquid to be treated. The driving liquid is passed through the forward osmosis membrane. The driving liquid is preferably an aqueous solution containing at least one selected from the group consisting of sodium chloride, magnesium chloride, sodium sulfate, magnesium sulfate, potassium chloride, lithium chloride, lithium bromide, sodium acetate, acetic acid, sodium oxalate, oxalic acid, sodium citrate, citric acid, sodium phosphate, phosphoric acid, and polyethylene glycol. The driving liquid may also contain an organic solvent. The ratio of water to organic solvent in the driving liquid is arbitrary, but is lower than the upper limit concentration of the organic solvent permitted by the forward osmosis membrane. The type of organic solvent contained in the liquid to be treated and the type of organic solvent contained in the driving liquid may be the same or different.

<Forward osmosis membrane>
In one embodiment, the forward osmosis membrane may have a dense layer and a base membrane layer. The dense layer may be a layer with a pore size of 2.0 nm or less, and the base membrane layer may be a layer with a pore size of more than 2.0 nm. The dense layer plays a role of allowing water molecules to pass through and blocking solutes of the liquid to be treated and solutes of the driving liquid. The base membrane layer is a layer that allows water molecules, solutes of the liquid to be treated, and solutes of the driving liquid to pass through, and plays a role of mechanically supporting the dense layer. The dense layer and the base membrane layer may be composed of the same or different chemical species.

A forward osmosis membrane may be configured as a module (hereinafter, also referred to as a forward osmosis membrane module) by loading a plurality of forward osmosis membranes. The solvent removal rate of the forward osmosis membrane module is expressed as Jw (kg/ ^m2 /h). Here, Jw is calculated from the following formula (1).
Jw=L/(M×H)...(1)
L is the amount of the treated liquid reduced (kg), M is the surface area of the dense layer of the forward osmosis membrane (m ² ), and H is the operation time (h).

During operation of the forward osmosis membrane module, solutes in the drive liquid may move to the treated liquid. This is called back diffusion of salts, and its speed is expressed as Js (g/ ^m2 /h). Js is calculated from the following formula (2).
Js=G/(M×H)...(2)
G is the amount of salt increase (g), M is the surface area (m ² ) of the dense layer of the forward osmosis membrane, and H is the operation time (h).

In one embodiment, the forward osmosis membrane has a mass of water permeating the forward osmosis membrane per unit time and a mass of organic solvent permeating the forward osmosis membrane per unit time that satisfy the following relationship:
0 < (mass of organic solvent permeating the forward osmosis membrane per unit time) / (mass of water permeating the forward osmosis membrane per unit time) × 100 ≦ 100
That is, the forward osmosis membrane according to one embodiment allows both water molecules and organic solvent molecules to permeate, but the amount of organic solvent molecules that permeates is smaller than the amount of water molecules.

There is no limit to the thickness of the dense layer of the forward osmosis membrane, but from the viewpoint of maintaining a high mechanical strength and solvent removal speed of the forward osmosis membrane, it is preferably 0.010 μm or more and 3.0 μm or less, more preferably 0.10 μm or more and 1.0 μm or less.

There is no limit to the thickness of the base film layer, but from the viewpoint of maintaining high mechanical strength and solvent removal speed, it is preferably 10 μm or more and 1000 μm or less, more preferably 15 μm or more and 500 μm or less, and even more preferably 20 μm or more and 350 μm or less.

There are no limitations on the shape of the forward osmosis membrane, and it may be a flat membrane or a hollow fiber membrane. In the case of a flat membrane, the base membrane layer may include, for example, a nonwoven fabric.

The chemical species constituting the forward osmosis membrane preferably includes at least one selected from the group consisting of polysulfone, polyethersulfone, polyimide, polybenzimidazole, polyvinylidene fluoride, polyacrylonitrile, polyketone, regenerated cellulose, polyamide, polyurea, zeolite, and metal organic framework (ZIF-8, UiO-66, etc.). From the viewpoint of achieving both the desolvation speed (dehydration speed when the solvent is water) and the blocking ability of the solutes of the treated liquid and the solutes of the driving liquid, at least one selected from the group consisting of polysulfone, polyethersulfone, polyimide, polybenzimidazole, polyvinylidene fluoride, polyacrylonitrile, polyketone, regenerated cellulose, polyamide, and polyurea is preferred.

When the forward osmosis membrane comes into contact with a high concentration of organic solvent, it may swell or dissolve. When the forward osmosis membrane swells, the pore size of the dense layer increases, so the diameter of the substance that can be blocked by the dense layer increases, and the solutes of the liquid to be treated and the driving liquid can easily pass through the forward osmosis membrane. Alternatively, if there is a difference in the swelling rate between the dense layer and the base membrane layer, defects may occur between the dense layer and the base membrane layer, and the solutes of the liquid to be treated and the driving liquid may easily pass through the forward osmosis membrane. In addition, depending on the type of organic solvent, the dense layer or the base membrane layer may be dissolved by the organic solvent, causing defects. Therefore, in the concentration using the forward osmosis membrane, it is preferable that the organic solvent concentration of the liquid to be treated and the driving liquid is equal to or lower than the upper limit concentration allowed by the forward osmosis membrane so that the membrane does not swell or dissolve. In particular, since the organic solvent concentration of the liquid to be treated increases as the concentration recovery process progresses, it is desirable to maintain the organic solvent concentration in the liquid to be treated below the upper limit concentration described below throughout the concentration recovery process.

The upper limit concentration refers to the maximum concentration at which Js/Jw calculated based on the upper limit concentration measurement test described below is 0.50 or less. From the viewpoint of long-term operation of the forward osmosis membrane, the upper limit concentration is more preferably a concentration at which Js/Jw is 0.40 or less, and more preferably a concentration at which Js/Jw is 0.35 or less. When the organic solvent concentration is not allowed to exceed the above upper limit concentration, swelling and deterioration of the forward osmosis membrane do not progress in a short period of time, which is preferable.

<Solvent addition mechanism>
The solvent addition mechanism has a role of adding a solvent to the liquid to be treated and adjusting the organic solvent concentration of the liquid to be treated. The concentration recovery device of this embodiment is provided with a solvent addition mechanism, so that the organic solvent concentration of the liquid to be treated that comes into contact with the forward osmosis membrane can be maintained at a desired level or lower. When exposed to a high concentration of organic solvent, the forward osmosis membrane can be deteriorated by swelling, dissolution, etc., and the solvent addition mechanism prevents the liquid to be treated that has an excessively high organic solvent concentration from coming into contact with the forward osmosis membrane, thereby suppressing deterioration of the forward osmosis membrane. An example of the solvent added to the liquid to be treated by the solvent addition mechanism is water. In a typical embodiment, the solvent is water. There is no limitation on the form of solvent addition, and the solvent may be added to the liquid to be treated before concentration by the forward osmosis membrane or during concentration by the forward osmosis membrane. The solvent addition mechanism may be connected to a tank for the liquid to be treated, may be connected to a line through which the liquid to be treated is sent to the forward osmosis membrane, or may be connected to a line through which the liquid to be treated that has left the forward osmosis membrane returns to the tank for the liquid to be treated.

<Ultrafiltration membrane>
The concentration and recovery device of this embodiment can be provided with a fractionation mechanism using one or more ultrafiltration membranes in front of the forward osmosis membrane (i.e., the upstream side of the liquid flow). When the size of the solute contained in the organic solvent-containing liquid is sufficiently large, the ultrafiltration membrane can fractionate and purify the liquid to some extent. In addition, when the organic solvent-containing liquid contains impurities other than the molecules to be concentrated, the impurities and the molecules to be concentrated can be separated by the fractionation mechanism. There are no limitations on the molecular weight cutoff and membrane shape of the ultrafiltration membrane. The molecular weight cutoff is preferably 1 kDa or more and 1000 kDa or less, or 3 kDa or more and 500 kDa or less, or 3 kDa or more and 100 kDa or less, or 3 kDa or more and 50 kDa or less, or 3 kDa or more and 10 kDa or less, or 5 kDa or more and 10 kDa or less. In addition, multiple ultrafiltration membranes may be used as the fractionation mechanism.
The ultrafiltration membrane may be operated in any manner. Generally, there is a dead-end type in which the liquid is fed perpendicular to the membrane by using centrifugal force, and a cross-flow type in which the liquid is fed parallel to the membrane. The cross-flow type is preferable because solutes are less likely to accumulate.

The ultrafiltration membrane may be provided between the tank for the treated liquid and the forward osmosis membrane, or a pretreatment tank 8 may be provided separately from the tank for the treated liquid, and an ultrafiltration membrane 7 may be provided between the pretreatment tank 8 and the tank for the treated liquid 1. In one embodiment, the tank for the treated liquid is disposed between the fractionation mechanism using the ultrafiltration membrane and the concentration mechanism using the forward osmosis membrane.

The ultrafiltration membrane may be, for example, a polymer membrane or a ceramic membrane.

<Measurement mechanism>
The concentration and recovery apparatus of this embodiment may be provided with a measurement mechanism for measuring the solvent composition (particularly the organic solvent concentration) in the organic solvent-containing liquid, which is the liquid to be treated. The measurement mechanism may be incorporated in the apparatus line or may be provided outside the line. As the measurement mechanism, one or more selected from the group consisting of a refractometer, a density meter, a liquid chromatography/mass spectrometry (LC/MS) device, a gas chromatography/mass spectrometry (GC/MS) device, an infrared spectrometer (IR) photometer, an ultraviolet-visible spectrometer (UV-vis) photometer, and a nuclear magnetic resonance (NMR) device may be used. These analysis methods can be used depending on the type and/or concentration of the solvent and solute. Among them, in terms of ease of measurement, one or more selected from the group consisting of a refractometer, a density meter, an infrared spectrometer (IR) photometer, and an ultraviolet-visible spectrometer (UV-vis) photometer are preferred, and an infrared spectrometer (IR) photometer and a refractometer are more preferred. Even in a mixed system containing multiple types of organic solvents, the concentration can be measured by the measurement mechanism 6 by creating a calibration curve in advance.

<Method of adding solvent>
The method of adding the solvent should preferably satisfy the following inequality:
(A+B)>C and
E/(D+E)>(E-Bt)/(D+E-At-Bt+Ct)
That is,
A-B×(D/E)<C<A+B
Where:
A is the rate at which water permeates the forward osmosis membrane (kg/h), B is the rate at which an organic solvent permeates the forward osmosis membrane (kg/h), C is the rate at which solvent (water) is added to the liquid to be treated (kg/h), D is the initial mass of water (kg) in the liquid to be treated, E is the initial mass of organic solvent (kg) in the liquid to be treated, At is the mass of water (kg) that permeates the forward osmosis membrane during time t after the start of concentration, Bt is the mass of organic solvent (kg) that permeates the forward osmosis membrane during time t after the start of concentration, and Ct is the mass of solvent (water) added to the liquid to be treated during time t after the start of concentration.

From the viewpoint of satisfying the above inequality, the method of adding the solvent is preferably any one of the following (i) to (iii).
(i) A method of adding a solvent (e.g., water) at a certain rate in accordance with the solvent removal rate of the forward osmosis membrane; (ii) A method of appropriately measuring the organic solvent concentration in the liquid to be treated and adding a solvent (e.g., water) according to the organic solvent concentration; (iii) A method of adding a sufficient amount of solvent (e.g., water) to the liquid to be treated in advance and then concentrating the liquid to be treated using a concentration recovery device. In any of the methods (i), (ii), and (iii), it is possible to concentrate the liquid to be treated without the organic solvent concentration exceeding the upper limit concentration of the forward osmosis membrane. From the viewpoint of shortening the total operation time, the above method (ii) is preferred.

<Concentration and regeneration mechanism of working liquid>
The driving liquid concentration and regeneration mechanism is a mechanism for removing the solvent from the diluted driving liquid and increasing the osmotic pressure. In the concentration and recovery device of this embodiment, the concentration and regeneration mechanism is not necessarily required, but it is preferable to use the concentration and regeneration mechanism from the viewpoint of long-term operation of the concentration and recovery device. The concentration and regeneration mechanism is preferably at least one selected from the group consisting of a reduced pressure distillation mechanism, a membrane distillation mechanism, and an evaporation and concentration mechanism using an evaporator.

<Operation of the concentration recovery device>
In one embodiment, the concentration and recovery apparatus can be operated at a liquid temperature in the range of more than 0° C. and not more than 50° C. From the viewpoint of high solubility of the solute and stable existence of the solute in the liquid, the operating temperature is preferably 4° C. or more and 40° C. or less, more preferably 10° C. or more and 30° C. or less. There may be a temperature difference between the liquid to be treated and the driving liquid.

The pressure applied to the forward osmosis membrane is preferably 100 kPa or less on both the treated liquid side and the driving liquid side, from the viewpoint of making it easy to concentrate the treated liquid without causing the solutes in the treated liquid and the driving liquid to adhere to the forward osmosis membrane, and making it difficult for the forward osmosis membrane to become compacted. The pressure here refers to the value indicated by a pressure gauge installed at the inlet of each liquid of the forward osmosis membrane when a predetermined amount of liquid is delivered during operation, and does not take into account osmotic pressure. The pressure difference between the treated liquid side and the driving liquid side is preferably 50 kPa or less, more preferably 20 kPa or less, from the viewpoint of enabling the forward osmosis membrane to be used for a longer period of time. It does not matter whether the pressure on the treated liquid side or the driving liquid side is higher.

When a fractionation mechanism using an ultrafiltration membrane is provided, the operating temperature of the ultrafiltration membrane may be the same as the temperature of the liquid being treated. In addition, the operating pressure is preferably 300 kPa or less, more preferably 200 kPa or less, and even more preferably 100 kPa or less, from the viewpoint of reducing adhesion of solutes to the ultrafiltration membrane.

<Determination of upper limit concentration>
The allowable upper limit concentration of the forward osmosis membrane for the organic solvent-containing liquid is the concentration at which the ratio of the desolvation rate (Jw) to the salt back diffusion rate (Js), Js/Jw, is 0.50 when the forward osmosis membrane is immersed in an organic solvent aqueous solution of a predetermined concentration for 2 hours, the forward osmosis membrane is washed with pure water, the liquid to be treated is pure water, the driving liquid is a 3.5 mass% sodium chloride aqueous solution, and the forward osmosis membrane is operated at a liquid temperature of 25° C. The method for determining the upper limit concentration will be described below. FIG. 7 is a schematic diagram showing a performance evaluation device for a concentration recovery device. The performance evaluation device 700 includes a driving liquid tank 15, a liquid delivery pump 16 for the driving liquid, a pure water tank 17, an electronic balance 18, a liquid delivery pump 19 for the pure water, and a forward osmosis membrane module 20.
The forward osmosis membrane module is connected to a performance evaluation device as shown in FIG. 7, and pure water (as the liquid to be treated) is passed through one side (the dense layer side in one embodiment) and a 3.5 mass% sodium chloride aqueous solution (as the driving liquid) is passed through the other side (the base membrane layer side in one embodiment) at 25° C. for 30 minutes, and the average dehydration rate and salt back diffusion rate for 30 minutes are calculated according to the above-mentioned formulas (1) and (2). At this time, the flow rate of each liquid is adjusted so that the pressure applied to the forward osmosis membrane by the pure water and the sodium chloride aqueous solution during the liquid passing is 20 kPa or less. After the measurement, the forward osmosis membrane is thoroughly washed with pure water. The sodium chloride contained in the liquid to be treated after the evaluation can be detected using a conductivity meter.

An organic solvent aqueous solution of a predetermined concentration is prepared, and the forward osmosis membrane module is immersed in the organic solvent aqueous solution for 2 hours so that the liquid is in sufficient contact with the forward osmosis membrane. The forward osmosis membrane module is then recovered and thoroughly washed with pure water. The performance of the forward osmosis membrane is evaluated again at 25°C using a performance evaluation device such as that shown in Figure 7, and the desolvation rate and salt back diffusion rate are calculated. Here, if Js/Jw is 0.50 or less, it is considered acceptable, and if it is greater than 0.50, the forward osmosis membrane is considered to have deteriorated. The organic solvent concentration of the liquid to be treated is increased by 5 mass% in increments such as 5 mass%, 10 mass%, and 15 mass%, and the maximum point at which Js/Jw is 0.50 or less is set as the upper limit concentration.

<Concentration and recovery of middle molecule solution>
An example of a method for concentrating and recovering a middle molecule solution containing an organic solvent will be described below.
A medium molecule solution having a predetermined organic solvent concentration and solute concentration is prepared. Here, the organic solvent concentration and solute concentration are as follows:
Organic solvent concentration (mass %)=(mass of organic solvent (g))/(mass of total solution (g))×100
Solute concentration (mass%)=(mass of solute (g))/(mass of total solution (g))×100
It is expressed as:
The middle molecular solution is concentrated in a concentration recovery device as the liquid to be treated. If necessary, the organic solvent concentration of the liquid to be treated during the concentration operation may be measured by a measurement mechanism. The organic solvent concentration, solute concentration, and solute concentration of the driving liquid after concentration are determined using the same analysis method as the measurement mechanism, for example, nuclear magnetic resonance or inductively coupled plasma-mass spectrometry (ICP-MS). In addition, after the forward osmosis membrane module is thoroughly washed with pure water after use, the liquid to be treated is pure water and the driving liquid is a 3.5 mass% sodium chloride aqueous solution, and the liquid temperature is 25°C. The flow rate is adjusted so that the pressure applied to the forward osmosis membrane from the liquid to be treated and the driving liquid is 20 kPa or less, respectively, and the performance can be evaluated by Js/Jw.

The recovery rate of the solute in the treated liquid after concentration can be calculated from the following formula (3).
Recovery rate = {(Middle molecule concentration (mass%) of the liquid to be treated after concentration) × (mass (g) of the liquid to be treated after concentration) × 100} / {(Middle molecule concentration (mass%) of the liquid to be treated before concentration) × (mass (g) of the liquid to be treated before concentration) × 100} ... (3)

In one embodiment, the recovery rate of the organic solvent-containing liquid is preferably 80.0% by mass or more, more preferably 95.0% by mass or more. The recovery rate is ideally 100% by mass, but from the viewpoint of ease of manufacturing the concentration recovery device, it may be, for example, 99.9% by mass or less, or 99.5% by mass or less.

When the performance evaluation of the forward osmosis membrane after the concentration operation shows that Js/Jw is 0.50 or less, the forward osmosis membrane can be considered not to have deteriorated, and the same forward osmosis membrane may be used again for the concentration operation.

<Concentration recovery method>
One aspect of the present invention also provides a method for concentrating and recovering an organic solvent-containing liquid. The method includes a concentration step of concentrating the organic solvent-containing liquid using a forward osmosis membrane, and in the concentration step, a solvent is added to the organic solvent-containing liquid. In one aspect, the concentration and recovery method may be carried out using the above-mentioned concentration and recovery device. Therefore, the components such as the forward osmosis membrane (hollow fiber membrane, etc.), ultrafiltration membrane, measurement mechanism, concentration and regeneration mechanism, organic solvent-containing liquid, and driving liquid used in the method, and the mode of concentration operation may be the same as those exemplified in the section "Concentration and recovery device".
Preferred examples of each step of the concentration and recovery method will be described below.

<Concentration process>
In this step, the organic solvent-containing liquid is concentrated using a forward osmosis membrane. In the concentration step, a solvent is added to the organic solvent-containing liquid. In the concentration step, the organic solvent-containing liquid is supplied to one side of the forward osmosis membrane, and a driving liquid is supplied to the other side of the forward osmosis membrane. The method of adding the solvent is not limited, and may be continuous or intermittent addition. It is desirable to add the solvent to the organic solvent-containing liquid so that the organic solvent concentration of the organic solvent-containing liquid is maintained within a range not exceeding the allowable upper limit concentration of the forward osmosis membrane described above in the section "Concentration and recovery device".

<Fractionation step>
The method of the present embodiment may further include a fractionation step of fractionating the organic solvent-containing liquid using one or more ultrafiltration membranes prior to the concentration step. The fractionated organic solvent-containing liquid obtained in the fractionation step may be supplied to the concentration step via a tank for treated liquid.

<Measurement of Solvent Composition>
The method of the present embodiment may further include observing the solvent composition in the organic solvent-containing liquid. The observation may be performed using the measurement mechanism exemplified in the section "Concentration and Recovery Apparatus". The observation of the solvent composition may be performed, for example, at a preset time interval during the concentration step.

<Driving solution concentration and regeneration process>
The method of the present embodiment may further include a driving liquid concentration and regeneration step of concentrating and regenerating the driving liquid diluted in the concentration step. For the concentration and regeneration, the concentrating and regeneration mechanism exemplified in the section "Concentration and recovery device" may be used.

The organic solvent-containing liquid can be concentrated by the process exemplified above. In one aspect, the recovery rate of the organic solvent-containing liquid by the method of this embodiment and the concentration of the solute contained in the driving liquid in the concentrated liquid recovered by concentrating the organic solvent-containing liquid are preferably within the ranges exemplified in the section entitled "Concentration and Recovery Apparatus."

Specific examples of the present invention are given below as examples and comparative examples, but the present invention is not limited to these scopes.

(Production Example 1)
A 20% by mass solution of polyethersulfone (BASF Ultrason) in N-methylpyrrolidone (NMP) was prepared, and the above solution was filled into a wet hollow fiber spinning machine equipped with a double-nozzle nozzle, and extruded into a coagulation tank filled with water to form hollow fibers by phase separation. The hollow fibers had an outer diameter of 1.0 mm and an inner diameter of 0.70 mm. The hollow fiber membranes were bundled and packed into a plastic housing so that the inner surface area was ¹⁰⁰ cm2, and the housing and the hollow fiber membrane bundle were bonded with a urethane adhesive to form a hollow fiber membrane module including the housing and the hollow fiber membrane bundle.

An aqueous solution containing 2.0% by mass of m-phenylenediamine and 0.10% by mass of sodium dodecyl sulfate was passed through the inner surface of the hollow fiber membrane for 5 minutes, followed by passing nitrogen at 5.0 L/min for 5 minutes, and then passing a hexane solution of 0.20% by mass of 1,3,5-benzenecarboxylic acid trichloride through it for 3 minutes to process it into a forward osmosis membrane module. The forward osmosis membrane module was washed overnight with pure water before use.

The solvent removal rate Jw and salt back-diffusion rate Js of the forward osmosis membrane were measured by a dehydration test using pure water and a 3.5% by mass aqueous sodium chloride solution. The delivery rates of the pure water and 3.5% by mass aqueous sodium chloride were 120 mL/min and 270 mL/min, respectively. Jw = 12.6 (kg/ ^m2 /h), Js = 2.8 (g ^/m2 /h).

Example 1
A forward osmosis membrane module was obtained according to Production Example 1. The desolvation rate Jw and salt back diffusion rate Js of the forward osmosis membrane were measured by a dehydration test using pure water and a 3.5 mass% sodium chloride aqueous solution. At this time, the liquid delivery rates of pure water and 3.5 mass% sodium chloride were 120 mL/min and 270 mL/min, respectively. Jw = 11.9 (kg/m ² /h), Js = 2.0 (g/ ^{m 2} /h). After immersing in 10, 15, 20, 25, and 30 mass% aqueous solutions of acetonitrile at 25°C for 2 hours, the forward osmosis membrane module was thoroughly washed with pure water. Js/Jw were 0.22, 0.19, 0.33, 0.45, and 0.97, respectively. Therefore, the upper limit concentration of organic solvent that the forward osmosis membrane can tolerate was set to 25 mass%.

0.80 g of alanylglutamine was dissolved in 500 g of 10% by mass acetonitrile aqueous solution to prepare a 0.157% by mass alanylglutamine solution. This was used as the treated liquid and a concentration experiment was performed using the concentration recovery device equipped with the forward osmosis membrane module. A 35% by mass magnesium chloride aqueous solution was used as the driving liquid. The liquid feed rates of the treated liquid and the driving liquid were 75 mL/min and 130 mL/min, respectively. During operation, water was added to the treated liquid at a rate of 1.0 g/min per minute. After 115 minutes, the mass of the treated liquid reached 100 g, so operation was stopped. The acetonitrile concentration of the concentrated treated liquid was measured by IR and a refractometer and found to be 19.2% by mass. The recovery rate was calculated using the above formula (3) and found to be 92.8%.

Example 2
A forward osmosis membrane module was produced according to Production Example 1. Jw = 11.9, Js = 1.9. A concentration experiment was carried out by preparing a liquid to be treated in the same manner as in Example 1, except that the water addition rate was 1.5 g/min. The operation was stopped after 135 minutes. The acetonitrile concentration in the liquid to be treated after the concentration experiment was 18.0 mass%. The recovery rate was calculated by the above formula (3) to be 91.3%.

Example 3
A forward osmosis membrane module was produced according to Production Example 1. Jw = 13.0, Js = 1.4. A liquid to be treated was prepared in the same manner as in Example 1, and a concentration experiment was carried out. However, the water addition rate was 2.0 g/min. The operation was stopped at 159 minutes. The acetonitrile concentration in the liquid to be treated after the concentration experiment was 14.4 mass%. The recovery rate was calculated using the above formula (3) and was 96.0%.

Example 4
A forward osmosis membrane module was produced according to Production Example 1. Jw = 9.9, Js = 2.2. A liquid to be treated was prepared in the same manner as in Example 1, and a concentration experiment was carried out. However, the water addition rate was 1.6 g/min. The operation was stopped after 144 minutes. The acetonitrile concentration in the liquid to be treated after the concentration experiment was 16.8 mass%. The recovery rate was calculated using the above formula (3) and was 91.9%.

Example 5
A forward osmosis membrane module was produced according to Production Example 1. Jw = 12.6, Js = 1.1. A liquid to be treated was prepared in the same manner as in Example 1, and a concentration experiment was carried out. However, water was not added until 55 minutes after the start of operation. From 56 minutes after the start of operation, the water addition rate was set to 2.0 g/min. The operation was stopped at 106 minutes. The acetonitrile concentration in the liquid to be treated after the concentration experiment was 16.8 mass%. The recovery rate was calculated using the above formula (3) and was 94.2%.

Example 6
A forward osmosis membrane module was produced according to Production Example 1. Jw = 11.5, Js = 2.4. A concentration experiment was carried out after preparing the liquid to be treated in the same manner as in Example 1 except that a 20% by mass aqueous solution of acetonitrile was used as the solvent. Here, the average desolvation speed of the forward osmosis membrane during concentration was measured and found to be 4.1 g/min. The acetonitrile concentration in the liquid to be treated was measured every minute using a refractometer in the tank for the liquid to be treated and every 5 minutes using IR measurement. When the concentration of acetonitrile reached 22% by mass, hydrogenation was started at 4.1 g/min, and when the concentration of acetonitrile reached 20% by mass, hydrogenation was stopped. The operation was stopped at 189 minutes. The acetonitrile concentration in the liquid to be treated after the concentration experiment was 21.9% by mass. The recovery rate was calculated using the above formula (3) and was found to be 91.6%.

(Example 7)
A forward osmosis membrane module was produced according to Production Example 1. Jw = 13.3, Js = 2.4. When the upper limit concentration of methanol was measured, Js / Jw was 0.30, 0.41, 0.44, and 0.59 when immersed in 30, 35, 40, and 45 mass% methanol aqueous solutions, respectively. Therefore, the upper limit concentration of organic solvents that the forward osmosis membrane can tolerate was set to 40 mass%. A 30 mass% methanol aqueous solution was used as the solvent to prepare a treated liquid in the same manner as in Example 1, and a concentration experiment was performed. Here, the average desolvation speed of the forward osmosis membrane during concentration was measured, and it was 4.5 g / min. The methanol concentration in the treated liquid was measured every minute by a refractometer in the treated liquid tank and every 5 minutes by IR measurement. When the concentration of methanol reached 40 mass%, hydrogenation was started at 4.5 g / min, and hydrogenation was stopped when the concentration of methanol reached 35 mass%. The operation was stopped at 108 minutes. The methanol concentration in the treated liquid after the concentration experiment was 33.6% by mass. The recovery rate was calculated to be 98.0% by the above formula (3).

(Example 8)
A forward osmosis membrane module was produced according to Production Example 1. Jw = 12.5, Js = 1.4. An experiment was carried out in the same manner as in Example 6, except that maltopentaose was used instead of alanylglutamine. The operation was stopped at 185 minutes. The acetonitrile concentration in the treated liquid after the concentration experiment was 21.1% by mass. The recovery rate was calculated using the above formula (3) and was 95.3%.

(Comparative Example 1)
A forward osmosis membrane module was produced according to Production Example 1. Jw = 9.9, Js = 1.2. The same liquid to be treated as in Example 6 was prepared, and a concentration experiment was carried out. However, water was not added. The operation was stopped after 89 minutes. The acetonitrile concentration in the liquid to be treated after the concentration experiment was 47.6 mass%. The recovery rate was calculated using the above formula (3) and was 79.0%.

(Comparative Example 2)
The same liquid to be treated as in Example 2 was fractionally concentrated using a vivaflow50R (manufactured by Sartorius, molecular weight cutoff 5,000 Da, membrane area ⁵⁰ cm2) as an ultrafiltration membrane. The liquid temperature was 25°C, and the operating pressure was 50 kPa. No water was added. The operation was stopped after 83 minutes. The acetonitrile concentration of the blocking liquid after the concentration experiment was 19.6 mass%. The recovery rate was calculated using the above formula (3) to be 6.3%.

The above results are summarized in Figures 8 to 16.

By adding the solvent, it was possible to operate the forward osmosis membrane at an organic solvent concentration below the upper limit of the forward osmosis membrane, which is expected to make the forward osmosis membrane less susceptible to deterioration by organic solvents.
For this reason, it is found to be useful to monitor the organic solvent concentration of the liquid being treated during operation and add water appropriately to carry out concentration within a certain organic solvent concentration range.

In addition, by operating the system with an organic solvent concentration below the upper limit, it is expected that the membrane will not deteriorate even if the same forward osmosis membrane is used repeatedly.

The present invention can be used in the concentration process of solutions containing organic solvents. Deterioration of the forward osmosis membrane due to swelling and dissolution can be suppressed by controlling the organic solvent concentration of the treated liquid by adding a solvent, making it possible to recover small molecules, which were difficult to recover using conventional methods, at a high recovery rate and in high concentration.

100, 200, 300, 400, 500, 600 Concentration and recovery device 700 Performance evaluation device 1 Tank for treated liquid 2 Solvent addition mechanism 3 Pump 4 Forward osmosis membrane 5, 15 Driving liquid tank 6 Measurement mechanism 7 Ultrafiltration membrane 8 Pretreatment tank 16 Driving liquid delivery pump 17 Pure water tank 18 Electronic balance 19 Pure water delivery pump 20 Forward osmosis membrane module

Claims (12)

An apparatus for concentrating and recovering an organic solvent-containing liquid, comprising:
The organic solvent-containing liquid contains water and at least one solvent selected from the group consisting of acetonitrile, methanol, isopropyl alcohol, ethyl acetate, hexane, toluene, and dimethyl sulfoxide;
The concentration and recovery device comprises:
one or more concentrating mechanisms using a forward osmosis membrane; and a solvent adding mechanism for adding water to the organic solvent-containing liquid.
A concentration recovery device comprising: 2. The concentration and recovery apparatus according to claim 1 , further comprising a measuring mechanism for observing the solvent composition in the organic solvent-containing liquid. The measurement mechanism is at least one selected from the group consisting of infrared spectroscopy (IR), a measurement method using a refractometer, a measurement method using a density meter, and an analysis method using liquid chromatography / mass spectrometry (LC / MS), gas chromatography / mass spectrometry (GC / MS), ultraviolet-visible spectroscopy (UV-vis), and a nuclear magnetic resonance device (NMR). The concentration and recovery apparatus according to claim 2 , which uses at least one selected from the group consisting of an analysis method using an ultraviolet-visible spectroscopy (UV-vis), and a nuclear magnetic resonance device (NMR). The concentration and recovery apparatus according to any one of claims 1 to 3 , wherein the organic solvent-containing liquid contains medium molecules having a molecular weight of 200 or more and 30,000 or less. 5. The concentration and recovery apparatus according to claim 1 , wherein the organic solvent-containing liquid contains at least one chemical species selected from the group consisting of amino acids, peptides, nucleic acids, and sugars. The concentration and recovery apparatus according to any one of claims 1 to 5, wherein a chemical species constituting the forward osmosis membrane includes at least one selected from the group consisting of polysulfone, polyethersulfone, polyimide, polybenzimidazole, polyvinylidene fluoride, polyacrylonitrile, polyketone, regenerated cellulose, polyamide, polyurea, zeolite, and metal-organic frameworks . The concentration and recovery apparatus according to any one of claims 1 to 6, wherein a driving liquid used in the concentration by the forward osmosis membrane is an aqueous solution containing at least one selected from the group consisting of sodium chloride, magnesium chloride, sodium sulfate, magnesium sulfate, potassium chloride, lithium chloride, lithium bromide, sodium acetate, acetic acid, sodium oxalate, oxalic acid, sodium citrate, citric acid, sodium phosphate, phosphoric acid, and polyethylene glycol. The concentration and recovery apparatus according to any one of claims 1 to 7 , further comprising a fractionation mechanism using one or more ultrafiltration membranes, which is provided in a stage preceding the concentration mechanism using the forward osmosis membrane. The concentration and recovery device according to any one of claims 1 to 8 , further comprising a mechanism for concentrating and regenerating the driving liquid. The concentration recovery apparatus according to claim 9 , wherein the concentration regeneration mechanism is any one of reduced pressure distillation, membrane distillation, and evaporation concentration using an evaporator. A method for operating a concentration and recovery apparatus in which the organic solvent concentration of an organic solvent-containing liquid does not exceed an upper limit concentration of a forward osmosis membrane used, comprising the steps of:
the organic solvent-containing liquid contains water,
The concentration and recovery device comprises:
one or more concentrating mechanisms using a forward osmosis membrane; and a solvent adding mechanism for adding water to the organic solvent-containing liquid.
Equipped with
a forward osmosis membrane is immersed in an organic solvent aqueous solution of a certain concentration for 2 hours, the forward osmosis membrane is washed with pure water, and then the forward osmosis membrane is operated with pure water as the treated liquid and a 3.5 mass% aqueous sodium chloride solution as the driving liquid, and the upper limit concentration is a concentration at which the ratio Js/Jw of the water permeation rate (Jw) to the back diffusion rate (Js) of salt is 0.50. The method for operating a concentration recovery apparatus according to claim 11 , wherein the concentration recovery apparatus is the concentration recovery apparatus according to any one of claims 1 to 10 .

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