JPH074508B2 - Separation method of mixed solution - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for separating a mixed solution using a permeable membrane.

[Prior Art] As one of methods for separating a mixed solution in which two or more components are mixed, such as a mixed solution of an organic liquid, research on a pervaporation method has been advanced. As shown in the principle of this pervaporation method, the separation tank 5 is divided into an upper solution chamber 3 and a lower decompression chamber 1 by a permeable membrane 4, and the mixed solution 2 is introduced into the solution chamber 3 as shown in FIG. Then, with the mixed solution 2 in contact with the permeable membrane 4, the decompression chamber 1
By depressurizing the inside, a specific component in the mixed solution 2 is preferentially permeated into the permeable membrane 4 and diffused, and a component permeated through the permeable membrane 4 is vaporized from the surface of the permeable membrane 4 on the decompression chamber 1 side. In this way, it is possible to separate and collect by collecting the components that have permeated and permeated the permeable membrane 4 in this way, or the mixture after the components that permeate the permeable membrane 4 have been removed in this way. By collecting the residual liquid of the solution 2, separation and collection can be performed.

[Problems to be Solved by the Invention] However, in this pervaporation method, the mixed solution 2 is in a state of being in direct contact with the permeable membrane 4, and the permeable membrane 4 generally formed of a polymer material permeates the mixed solution 2. Easily swelled by. When the permeable membrane 4 is swollen in this way, the permeable membrane 4
However, there is a problem that the membrane function is deteriorated and it is difficult to separate the mixed solution 2 with high separation performance.

The present invention has been made in view of this point, and an object thereof is to improve the separation performance of a mixed solution.

[Means for Solving Problems] In the present invention, however, the permeation that preferentially permeates a specific component separated and recovered from the mixed solution 2 between the decompression chamber 1 and the solution chamber 3 into which the mixed solution 2 is introduced. The membrane 4a is provided in contact with the mixed solution 2, and the decompression chamber 1 is partitioned by a permeable membrane 4b that preferentially permeates a specific component of the mixed solution 2 other than the specific component to be separated and recovered, and is close to the solution chamber 3. Room 1a on the side and room 1b on the far side
And the chamber 1b on the side farther from the solution chamber 3 in the decompression chamber 1 is decompressed to allow the mixed solution 2 to permeate the permeable membrane 4b between the solution chamber 3 and the decompression chamber 1 and Chamber 1a near the solution chamber 3
The vaporized vapor is vaporized into the chamber 1a on the side closer to the solution chamber 3, and the vaporized vapor is further permeated into the permeable membrane 4b partitioning the interior of the decompression chamber 1 to permeate into the chamber 1b on the side far from the solution chamber 3, The present invention relates to a method for separating a mixed solution, which is characterized in that the separated liquid is recovered from the chamber 1a on the side closer to the solution chamber 3 in the decompression chamber 1.

The present invention will be described in detail below. FIG. 1 shows an example of the principle device of the present invention, in which the separation tank 5 is divided into a lower decompression chamber 1 and an upper solution chamber 3 by a permeable membrane 4a, and the bottom of the solution chamber 3 is divided by a permeable membrane 4a. The mixed solution 2 introduced into the solution chamber 3 in such a manner as to be formed is brought into contact with the entire surface of the permeable membrane 4a. Further, a permeable membrane 4b is provided in the decompression chamber 1 so that the decompression chamber 1 has a chamber 1a close to the upper and lower two solution chambers 3 and a chamber far from it.
It is divided into 1b partitions. By reducing the pressure in the chamber 1b of the decompression chamber 1, the chamber 1a is passed through the permeable membrane 4b.
The inside is also in a depressurized state.

Then, the mixed solution 2 in contact with the permeable membrane 4a permeates into the permeable membrane 4a and diffuses, but the permeable membrane 4a preferentially permeates and diffuses a specific component of the mixed solution 2. The mixed solution 2 which has permeated the permeable membrane 4a is vaporized in the chamber 1a of the decompression chamber 1 in a decompressed state. Mixed solution 2 on the permeable membrane 4a
Since the specific component therein preferentially permeates, the vaporized vapor in the chamber 1a is in a state where the concentration of the specific component is increased. Next, when this vapor that has reached the inside of the chamber 1a comes into contact with the permeable membrane 4b, it permeates the permeable membrane 4b and is diffused, so that
Since 1b is in a higher depressurized state, it permeates the permeable membrane 4b and reaches the chamber 1b side. At this time, the permeable membrane 4b preferentially permeates and diffuses other specific components of the mixed solution 2, and other specific components of the vapor in the chamber 1a preferentially penetrate.
Through the solution chamber 3 to the chamber 1b on the far side, and other characteristic components are removed from the vapor in the chamber 1a, and the concentration of the specific component is further increased.

For example, when a water-alcohol solution is used as the mixed solution 2 to separate water and alcohol, a permeable membrane is used.
An alcohol-selective material that preferentially permeates alcohol is used as 4a, and a water-selective material that preferentially permeates water is used as the permeable membrane 4b. When the chamber 1b of the decompression chamber 1 is decompressed, first, the permeable membrane 4a preferentially permeates alcohol, so that the alcohol component of the mixed solution 2 preferentially permeates into the permeable membrane 4a, and the permeable membrane 4a enters from the chamber 1a side. The vaporized vapor has a high alcohol concentration. Next, the water contained in the vapor of which the alcohol concentration is increased in the chamber 1a is preferentially permeated through the permeable membrane 4b to be moved to the chamber 1b, and as a result, the moisture in the chamber 1a is reduced. Water can be removed from the steam to further increase the alcohol concentration. Thus, as the permeable membrane 4a between the decompression chamber 1 and the solution chamber 3, a specific component to be separated and recovered from the mixed solution 2, that is, an alcohol-selective one is used, and the permeable membrane 4b for partitioning the decompression chamber 3 is separated. By using a specific component other than the specific component to be recovered, that is, a water-selective component, it becomes possible to recover the alcohol component from the water-alcohol solution in a highly separated state from the chamber 1a. It is also possible to separate the two components from the mixed solution 2 independently, such as the alcohol component from the chamber 1a and the water from the chamber 1b. Of course, by increasing the number of the permeable membranes 4a, 4b ... to be three or four, it becomes possible to separate the multi-components from the mixed solution such as three-components and four-components.

Here, as the permeable membrane, a so-called non-porous membrane can be used, and a membrane used in a conventional pervaporation method can be used. For example alginate film,
Chitosan film, crosslinked chitosan film, chitosan acetate film, quaternized chitosan film, polystyrene film, polyvinylidene chloride film, silicon (polydimethylsiloxane) film, polyvinylidene fluoride film, cellulose nitrate film, cellulose acetate film, crosslinked polyvinyl alcohol Film, polyamic acid film,
Examples include poly (1-trimethylsilyl) -1-propyne film and styrene-dimethylsiloxane-based graft copolymer film. Among the permeable membranes enumerated in this way, for example, when separating a water-alcohol mixed solution as described above, as a water-selective membrane, an alginic acid membrane, a chitosan membrane, a crosslinked chitosan membrane, a polystyrene membrane, a crosslinked polyvinyl alcohol membrane, a polyamic acid. An acid film or the like, and a polydimethylsiloxane film, a poly (1-trimethylsilyl) -1-propyne film, a styrene-dimethylsiloxane-based graft copolymer film, or the like can be selected and used as the alcohol-selective film. Moreover, since the permeation rate in the permeable membrane is inversely proportional to the film thickness, the permeation rate can be increased by reducing the film thickness of the permeable membrane, and the performance of separating the components of the mixed solution is independent of the film thickness. Therefore, it is possible to improve the membrane performance by thinning the permeable membrane. The permeation rate in the permeable membrane is also affected by the degree of pressure reduction in the decompression chamber, and the permeation rate can be increased as the degree of pressure reduction in the decompression chamber increases, that is, as the vacuum is increased. Since the permeable membrane is usually fragile and cannot withstand the decompressed state of the decompression chamber in many cases, polypropylene non-woven fabric or polyester non-woven fabric, Teflon or polysulfone porous film, porous glass plate or It is preferable that the permeable membrane is supported by a porous support such as a porous ceramic plate, and this support prevents the permeable membrane from being broken in the decompressed state of the decompression chamber.

Although various mixed solutions can be separated using the method of the present invention, it is particularly effective for separating mixed solutions that cannot be separated by ordinary distillation. For example, water-alcohol system and water-aromatic compound system, water-alcohol and aromatic compounds from an azeotropic mixture such as ether system, recovery of ethers, separation recovery of organic solvents such as hydrocarbons having a boiling point close, Separation and collection of a mixture of structural isomers such as a mixture of o-, m- and p-xylene, separation and collection of a mixture of optical isomers such as dextrorotatory and levorotatory, drugs and biological substances, fruit juice, and a polymerizable monomer Separation of thermally decomposable or heat-alterable mixtures such as the body, separation of products from the reaction mixture to promote the reaction by shifting the equilibrium of the reaction, ammonia and amines, hydrogen sulfide, carbon dioxide from wastewater The present invention can be effectively applied to separation and removal of volatile organic mixtures such as sulfurous acid gas. In addition, the separation and concentration of alcohol from biomass, the separation and recovery of expensive organic solvents such as dimethylformamide, dimethylacetamide, and dimethylsulfoxide from the synthetic fiber spinning bath, the solvent in the paint waste liquid that occurs during paint manufacturing and in the coating line Separation and collection, separation and concentration of alcohol mixture and organic solvent mixture in chemical factory, or separation and collection of salts in these mixtures, collection of trichlene used for dry cleaning, concentration treatment of emulsion solution, solution of radioactive material Concentration, concentration and separation of rare earth ions from solution, concentration of virus and bacteriophage, production of sterile water and non-pyrogenic water for pharmaceuticals, hospitals, hemodialysis, etc., production of ultrapure water for electronics industry, etc. The present invention can also be applied.

[Examples] The present invention will be further described below with reference to Examples.

Example 1 Using the apparatus shown in FIG. 1, an alcohol-selective polydimethylsiloxane membrane that preferentially permeates alcohol as the permeation membrane 4a in FIG. 1 and a water selection that preferentially permeates water as the permeation membrane 4b. A dialdehyde cross-linked chitosan membrane was used, respectively. Here, the permeation area of the dialdehyde cross-linked chitosan membrane is 5 times that of the polydimethylsiloxane membrane.
The size of the membrane was adjusted so that it would double.

The polydimethylsiloxane film consists of 7 parts by weight of polydimethylsiloxane and 0.25 parts by weight of the catalyst as a curing agent.
RA (manufactured by Shin-Etsu Chemical Co., Ltd.) and 49 parts by weight of benzene were mixed, and after stirring this, the mixture was cast on a stainless steel film-forming device and dried by standing at 25 ° C. for 6 hours to form a film having a thickness of 100 μm. It was obtained by forming a film.

A dialdehyde crosslinked chitosan film was prepared as follows. That is, a cast solution prepared by degassing a 1% by weight chitosan solution in a 1N acetic acid aqueous solution under reduced pressure was cast on a flat dish for film formation, and allowed to stand in a constant temperature dryer at 60 ° C for 6 hours. The solvent was allowed to evaporate completely and the chitosan acetate film was deposited. The chitosan acetate film was peeled from the flat dish and immersed in a 1N aqueous sodium hydroxide solution to obtain a chitosan film. Next, 0.5% as a catalyst in 0.4% glutaraldehyde aqueous solution.
By dipping this chitosan film in a solution prepared by adding a sulfuric acid aqueous solution of N at room temperature for 15 minutes, cross-linking chitosan with dialdehyde, washing with water, and drying under reduced pressure at room temperature,
A dialdehyde cross-linked chitosan film having a thickness of 20 μm was obtained.

Then, an aqueous ethanol solution having various concentrations is introduced into the solution chamber 3 as the mixed solution 2, each chamber 1a, 1b of the decompression chamber 1 is adjusted to an atmosphere of 40 ° C., and the chamber 1b is 1.5 × 10 ⁻² Torr.
The pressure was reduced to r. At this time, the depressurizing operation is performed in the chamber 1a.
The chamber 1b was kept in the suction state for 1 hour while the valve 6 of the chamber 1b was closed and the valve 7 of the chamber 1b was opened. After this operation, the concentration of ethanol in the vapor in the chamber 1a of the decompression chamber 1 was measured. The results are shown in Table 1.

Comparative Example 1 Using the apparatus shown in FIG. 2, a polydimethylsiloxane membrane was used as the permeable membrane 4, and the depressurization chamber 1 was depressurized for 1 hour in the same manner as in Example 1. After this operation, the concentration of ethanol in vapor in the decompression chamber 1 was measured. The results are shown in Table 1.

As can be seen from Table 1, in Example 1 which is a method in which a permeable membrane is further added to the pervaporation method than in Comparative Example 1 by the pervaporation method, separation is performed in a state where the concentration of ethanol is increased. It is confirmed that they can be collected.

Examples 2 and 3 Using the apparatus shown in FIG. 1, the atmospheric temperature of each chamber 1a, 1b of the decompression chamber 1 was set to 25 ° C. (Example 2) and 55 ° C. (Example 3), respectively. Others are the same as in Example 1 and room 1a
The concentration of ethanol in the steam inside was measured. The results are shown in Table 2.

Comparative Examples 2 and 3 Using the apparatus shown in FIG.
The concentration of ethanol in the vapor in the decompression chamber 1 was measured in the same manner as in Comparative Example 1 except that the temperature was set to 55 ° C. (Comparative Example 2) and 55 ° C. (Comparative Example 3), respectively. The results are shown in Table 2.

Similarly in Table 2, Comparative Examples 2 and 3 by pervaporation method
From the above, it is confirmed that Examples 2 and 3, which are a method in which a permeable membrane is added to the pervaporation method, can be separated and recovered in a state where the concentration of ethanol is increased.

[Effects of the Invention] As described above, in the present invention, a permeable membrane that preferentially permeates a specific component that is separated and recovered from the mixed solution is provided between the decompression chamber and the solution chamber into which the mixed solution is introduced. The pressure reducing chamber is divided into a chamber closer to the solution chamber and a chamber farther from the solution chamber by partitioning the decompression chamber with a permeable membrane that preferentially permeates specific components other than the specific component that separates and collects the mixed solution. , The chamber on the side far from the solution chamber in the decompression chamber is decompressed, and the mixed solution is permeated into the permeable membrane between the solution chamber and the decompression chamber to vaporize into the chamber near the solution chamber in the decompression chamber and this solution. The vaporized vapor in the chamber on the side closer to the chamber is further permeated into the permeable membrane that partitions the decompression chamber and permeates into the chamber on the side far from the solution chamber,
Since the separated liquid is collected from the chamber on the side close to the solution chamber in the decompression chamber, the permeable membrane between the solution chamber and the decompression chamber preferentially permeates a specific component to be separated and collected from the mixed solution to decompress the decompression chamber. It is possible to increase the concentration of this specific component in the chamber on the side close to the solution chamber, and to separate the specific component other than the specific component to be separated and recovered in the vapor in the chamber near the solution chamber in the decompression chamber. A specific component other than the specific component that is permeated through the permeable membrane that partitions the decompression chamber and separated into the chamber on the side far from the solution chamber in the decompression chamber and separated and recovered from the vapor in the chamber near the solution chamber in the decompression chamber It is possible to further increase the concentration of the specific component to be removed and separated and recovered, and it is possible to recover with a high concentration of the specific component to be separated and recovered from the chamber near the solution chamber in the decompression chamber. By pervaporation method It is capable of improving the separation performance of the mixed solution. In separating the mixed solution as described above, the depressurization of the chamber far from the solution chamber is continued while the vapor having a high concentration of the specific component to be separated and recovered is retained in the chamber near the solution chamber in the depressurization chamber. Then, in accordance with the depressurization duration, other specific components other than the specific component to be separated and recovered in the vapor in the chamber near the solution chamber in the depressurization chamber permeate and permeate the permeable membrane partitioning the depressurization chamber to be reduced. Therefore, it is possible to further increase the concentration of the specific component to be separated and recovered in the chamber on the side closer to the solution chamber in the decompression chamber, and by extending the decompression duration, the chamber on the side closer to the solution chamber in the decompression chamber. The specific component to be separated and recovered from the can be recovered in a state where the concentration of the specific component is further increased.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus used in the present invention, and FIG. 2 is a schematic view of an apparatus used in a conventional pervaporation method. 1 is a decompression chamber, 1a and 1b are decompression chambers, 2 is a mixed solution, 3
Is a solution chamber, 3a and 3b are partitioned chambers in the solution chamber, and 4a and 4b are permeable membranes.

Claims (1)

[Claims] 1. A decompression chamber is provided between a decompression chamber and a solution chamber into which the mixed solution is introduced, in a state in which a permeable membrane that preferentially permeates a specific component separated and recovered from the mixed solution is in contact with the mixed solution. Divide into a chamber on the side close to the solution chamber and a chamber on the side far away by partitioning with a permeable membrane that preferentially permeates specific components other than the specific component to be separated and collected in the mixed solution, on the side far from the solution chamber in the decompression chamber. The chamber was decompressed and the mixed solution was permeated into the permeable membrane between the solution chamber and the decompression chamber to vaporize into the chamber close to the solution chamber in the decompression chamber and vaporize into the chamber close to the solution chamber. A method for separating a mixed solution, characterized in that vapor is further permeated through a permeable membrane that partitions the decompression chamber to permeate into a chamber on the side far from the solution chamber, and the separated liquid is recovered from a chamber on the side closer to the solution chamber in the decompression chamber. .