JPS6097003A - Membrane separation method - Google Patents

Abstract

PURPOSE:To enhance separation efficiency and a permeation speed, in separating a solution mixture by a pervaporation method, by allowing the solution mixture to pass through a non-porous layer through a porous layer. CONSTITUTION:A porous layer comprises a layer having substantially no separation capacity and a pore size of about 100-several mum and is prepared by using polysulfone, cellulose acetate, cellulose nitrate, a homopolymer or copolymer of vinyl chloride or a blend thereof. A non-porous layer comprises a layer having no piercing pore observable by an electronic microscope and has a thickness of 100-10,000Angstrom and is prepared by using polyurea, polyetheramide, polyether urea, polyamide, polyether, a homopolymer or block or graft copolymer of polyvinyl halide or a blend thereof.

Description

[Detailed Description of the Invention] [Technical Field] The present invention provides a method for separating a mixed liquid by a pervaporation method using a composite membrane having a porous layer and a non-porous layer made of a different material. It is related to.

[Prior art and its problems]

Separation technologies using membranes have been actively studied in recent years, and some of them have even been put into practical use. Practical examples include:
For example, it can be found in many processes such as seawater desalination using reverse osmosis membranes, salt production using ion exchange membranes, and recovery of electrodeposition paint using ultrafiltration membranes. Separation using membranes has attracted attention from various fields as an energy-saving separation method that can replace conventional distillation methods.Furthermore, it has been widely used in the United States and Research is active mainly in Europe and Japan.

A pervaporation method is being researched as one method for such membrane separation. This technique supplies a mixed liquid through the membrane on one side and evaporates the mixed liquid in the membrane by applying a vacuum or flowing gas to the other side.
The mixed liquid is separated into each component based on the difference in affinity between the membrane and the mixed liquid. The feature of this technology is that unlike reverse osmosis, there is no concentration limit due to osmotic pressure, so it is not limited to separating mixed liquids with low concentrations, but can separate mixed liquids with a whole range of concentrations. , and also azeotropes,
These include solvents with similar boiling points and the ability to separate isomers (for example, ortho and para isomers, and cis and trans isomers).

However, the reason why the pervaporation method has not reached practical use at present is that firstly, the decomposition rate α (α = VX
/ XV: Fraction of component A in the stock solution x.

The fraction of the component x, the fraction of the A component in the permeate, the fraction y of the 1B component in the permeate, is equivalent to or slightly better than the fraction of distillation.There are sufficient advantages of passing the membrane with a pusher claw. The second problem is that the permeation rate Q (Q-F
/T-3: F is transmission l, ■ is time.

This is because the membrane area (S: membrane area) is at a practically low level, and a membrane with a permeation rate of at least 10 times the currently known permeation rate is required.

Regarding pervaporation, many patent documents have been known for a long time, but recently, Japanese Patent Application Laid-Open No. 58-4
0102.58-40103.58-40104.51
-40105.58-58106.58-58107.
58-5810f3.58-95521.58-955
22.58-95523, etc., various separation methods are shown.

In some of these patent documents, the permselectivity of the components to be permeated in the mixed liquid is reversed depending on the separation method.

On the other hand, in the composite membrane, the permeation rate of 0 can be reduced to 0 by providing as thin a polymer cord as possible, which determines the substance function. A porous layer that does not have any properties per se, and a non-porous layer of a polymeric material that has the properties of the above-mentioned substance, which is a different material, are used for the purpose of This structure has been extensively developed mainly in the field of inverted diaphragm gas membranes.

[Purpose of the invention] The present inventors applied a composite membrane to the barbage parage milling method, and achieved high α and high Q by IH.
The present invention was completed by discovering a method for distributing mixed liquids more effectively.

[Structure of the invention]

In other words, this defense is based on the fact that when a mixed liquid is separated by a pervaporation method using a composite membrane that has a porous layer that has a substantially opposite separation ability and a non-porous layer that is responsible for the porous layer and the material, the mixed liquid This involves two people.

The porous 11 layer referred to herein is a layer having substantially no separation performance and has many through holes. It has the form of a flat membrane or a hollow membrane, and its pore diameter is about 100 to several microns, and can be confirmed by drilling with an electron microscope. More preferably, the size of the micropores on one side is about 100.
The pore diameter gradually increases toward the other side, and is about several microns on the other side. Further, the material for this porous layer can be selected from various organic polymers and inorganic materials.

It is usually an organic polymer because of its ease of processing.

Homopolymers or polymers such as polysulfone, cellulose acetate, cellulose nitrate, and vinyl chloride, or blends of these are used. Porous membranes that can be used as porous layers include, for example, a solution of polysulfone in dimethylformamide (IMF) poured onto a glass plate to a certain thickness, and then soaked in water or an aqueous solution, for example, 0.5% sodium dodecyl sulfate. By wet coagulation in an aqueous solution containing a small amount of r% and 2% by weight of DMF, a porous membrane having a majority of its surface with fine pores of about 100 mm or less in diameter is prepared. is obtained.

This porous TLT membrane is made of woven fabric or non-woven fabric.
It may be 4.

In addition, a non-porous layer is a layer that does not have at least through holes that can be observed with an electron microscope, and the
000A is preferred. If the thickness is thinner than this range, it may get damaged during use.

Also, if it is too thick, Q will be insufficient. As such a non-porous layer, a porous layer and a material are used.

For example, it can be selected from various organic polymers and inorganic materials, but organic polymers are generally preferred, such as polyurea and polyetheramide.

Polyether urea, polyamide, polyester.

A homopolymer such as polyether polyvinyl halide, a block copolymer, a graft copolymer, or a blend is used for the defecation port 1. Preferably, from the viewpoint of solvent resistance and durability, a crosslinked polymer, particularly a crosslinked product of the above polymer, is used. Since crosslinkable polymers are insoluble in solvents and cannot be synthesized and then imitated, a composite membrane is formed by separately creating a porous !19[T'711['wA]. Composite membranes made by this method are the mainstream of composite membranes in modern times.In this way, composite membranes are made of thin 41.
The part of the porous layer: the part of 1111m that supports f'! ). A reverse osmosis membrane is a composite membrane.

NS-100, NS-200 (North Star rtll
The product 'C- developed for this purpose is a prism film <More 4j
1) Nato is known. The forms of these composite membranes include hollow fibers and flat membranes, but the present invention is of course not limited to the form. A typical example will be shown in the later examples by standing in a transmission electron microscope.

J, lko, here's the fortune teller l゛\-A homogeneous mixed liquid consisting of Veronians and (2 components on the 11 sides of the membrane, t: /, -1, t1' loss L 17) components. The 119 components of the mixed liquid are separated based on the difference in affinity, and then the membrane is separated on the other side of the membrane by drawing air or flowing an inert gas. This is a membrane separation method in which the components that have passed through the membrane are taken out as a gas, and the liquid is recovered by cooling the gas.

The mixed liquid separated in the present invention is a homogeneous mixed liquid of two or multiple components, such as benzane/toluene, benzene/'cyclohexane, benzene, /1)-bequinone, 0-xylene, 27'p-xylene, etc. Organic mixture system, water/methanol, water/Jtanol, water/I+-propyl alcohol, water/1so-1[]pyral, water/acetane, water/di-quaternary alcohol, water/ Examples include dimethyl small lumamide, water/organic mixture systems such as water/acid resistant.

Special feature c: It has a remarkable effect on the separation of II systems, and is useful for the separation of water and nonorkol systems, for example. The fact that it is effective to effectively separate these mixed liquids by the method of the present invention will be explained in detail with the following examples, but the interpretation of the present invention is not limited by these examples. isn't it.

Reference example 1 Installation of polysulfone microporous membrane.

Polysulpon 15 parts, dimethylborno, amide 85
I adjusted the casting liquid in the heavy lifting part and it was 7.

Apply this casting solution to dry glass root soil without scratches.
It was cast to a thickness of μm. Immediately after that, the cast membrane was quickly and quietly put into water along with the cuff plate at a constant speed.The polysulfone microporous membrane peeled off from the glass plate after 4 seconds, but it was kept in a drain for 10 minutes. The polysulfone microporous membrane obtained in this way was made of a polysulfone microporous membrane. Electron micrographs confirmed that there were relatively large holes near the surface that was in contact with the cuff plate.

EXAMPLE A 3% aqueous solution of J Biami]/(1 tileshicyamine modified Boryevik [J Ruhid 1]) was prepared.

Apart from this and IJ, 19- % hexane solution was prepared.

A T-biamine aqueous solution was uniformly applied to the surface of the polysulfone microporous membrane prepared in Reference Example 1 that was in contact with air during casting.
After soaking, hold the membrane vertically and drain the liquid for 30 seconds. Next, the membrane was held horizontally and the isophthalic acid chloride solution was uniformly poured into the membrane, and the solution was left for 1 minute.
Drying was performed in a hot air circulation dryer for 0 minutes. It was confirmed from electron micrographs that the composite membrane prepared in this way had an active layer made of shrimp amine crosslinked polymer on one side of the polysulfite membrane. The active layer of this composite membrane made of J Piamine cross-linked polymer T was oriented toward the gas phase, and its permeation capacity was measured at a humidity of 30°C, a 10% ethanol aqueous solution, and a pressure of 10 mm on the gas phase side. The binding is shown in Table 1.

Example 2 33% Piamine aqueous solution was replaced with 2% polyethyleneimine aqueous solution'a (J was changed in the same manner as in Example 1!!!8
One film was evaluated in the same manner as in Example 1.
Small size on the front.

-1()- Example 3 Isophthalic acid chloride 1% hekylene solution.

A membrane was formed in the same manner as in Example 2, except that the 1% hexane solution of tolylene diisocyanate was replaced with a 1% hexane solution of modified isophthalic acid chloride.

Table 1 shows the results of evaluation in the same manner as in Example 1. A transmission electron micrograph of the membrane thus obtained is shown in FIG. .

Example 5 A 2% aqueous solution of metaphenylenediamine was prepared. Apart from this, 0.1% Freon T of trimesoyl chloride
A F solution was prepared.

2% of the single membrane of the polysulfone microporous membrane prepared in Reference Example 1
After being immersed in the metaphenylenediamine aqueous solution for 1 minute, the liquid was drained for 30 seconds. Next, the membrane was immersed in a trimesoyl chloride solution for 10 seconds, then drained and dried at room temperature. The separation performance of the thus obtained membrane by pervaporation method was measured in the same manner as in Example 1. The results are shown in Table 1. A transmission electron micrograph of this film is shown in FIG. Non-porous and porous layers were observed.

Example 6 2 parts by weight of furfuryl alcohol, 2 parts by weight of sulfuric acid.

A mixed solution of 20 parts by weight of isopropyl alcohol, 0.7 parts by weight of sodium dodecyl sulfate, and 75.3 parts by weight of water and 0 parts by weight was prepared.

A single membrane of the polysulfone microporous membrane prepared in Reference Example 1 was immersed in the above mixed solution for 15 minutes, and then drained for 1 minute. Next, the membrane was dried at 150° C. for 15 minutes in a hot air circulating dryer. The separation performance of the thus obtained membrane by pervaporation method was measured in the same manner as in Example 1. The results are shown in Table 1.

Example 7 The separation performance of Toshi's PEC-1000 membrane by the pervaporation method was measured in the same manner as in Example 1.

The results are shown in Table 1. Furthermore, a transmission type electron mirror photograph of this film is shown in FIG. A non-porous layer and a porous layer can be observed.

Comparative Examples 1 to 7 Composite membranes prepared in Examples 1 to 7 were prepared in Table 1, except that the active layer side of each membrane was directed toward the stock solution side.

14-

[Brief explanation of the drawing]

Figures 1 to 3 are electron micrographs (9
0000 times). FIG. 1 relates to Example 4, FIG. 2 to Example 5, and FIG. 3 to Example 6. Patent applicant Director of Institute of Industrial Technology 15-

Claims (1)

[Claims] When a mixed liquid is separated by a pervaporation method using a composite membrane having a porous layer having substantially no separation ability and a non-porous layer made of a material different from the porous layer, the mixed liquid is passed through the porous layer. A membrane separation method characterized by passing through a non-porous layer.