JPS607906A - Manufacture of dynamic membrane - Google Patents

Abstract

PURPOSE:To obtain a dynamic membrane having a higher solute excluding performance than the dynamic membrane consisting separately of alumina sol and colloidal silica by combining both materials. CONSTITUTION:An organic porous support such as ceramics and sintered metallic powder can be exemplified as the porous support. The alumina sol, consisting of feathery particles having 50X5-400X40mum particle size and using an organic and an inorganic acid such as acetic and hydrochloric acid as a stabilizer, is used. The solubility in water of colloidal silica is preferably stabilized with acidity. The amt. of the aq. soln. contg. colloidal silica is regulated to 20- 50l per 1m<2> surface area of the support to manufacture the dynamic membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an extradynamic membrane suitable for ultrapolar applications. Specifically, the present invention relates to a method for producing a dynamic membrane having a two-layer structure consisting of alumina sol and colloidal silica.

Conventionally, dynamic membranes using alumina sol are well known, and their ultra-P performance is, for example, in the case of filtration of a 5% gelatin aqueous solution equivalent to J-S4 type, at a pressure of 20 kg/d.
The solute exclusion rate was about 96 to 22% under the following conditions: G, flow rate along the membrane strip, o, tm7θec, and temperature O: θ°C. Also,
A dynamic membrane made of colloidal silica is also well known, and its ultra-P performance under the same conditions as above was about 9, with a solute rejection rate of 7 to 2.

That is, depending on the dynamic Im of the alumina sol, 3~3I6 of the solute will be lost with the permeate water, and with the dynamic membrane of colloidal silica, 2~3X of the solute will be lost along with the permeate water. .

Therefore, if the solute rejection rate, which reaches several % of 2θ, can be further improved by a point, it will be possible to reduce the amount of solute loss by a considerable percentage, and if the solute component is expensive, the effect will be extremely high. big.

In view of these circumstances, the inventors of the present invention have conducted extensive research and have discovered that by combining alumina sol and colloidal silica, a dynamic membrane made of these individual materials has higher elution and removal performance. , arrived at the present invention.

The present invention will be explained in detail below.

As the porous support used in the present invention, various known ones can be mentioned. Examples include ceramics, sintered maple powder, sintered glass powder, carbon materials, and other inorganic porous materials, as well as various synthetic resins such as cellulose acetate, polyvinyl chloride, polymethacrylonitrile, polyamide, and fluororesin. The porous support is removed.

The diameter of the surface pores of the porous support varies depending on the material, but is usually θ, θ/~-μ, preferably 0. θ! ~θ, 2μ is used.

The thickness of the porous support is not particularly limited and depends on the intended use of the dynamic membrane.

It is sufficient as long as it has mechanical strength.

As an alumina sol, the particle size is great! θ×jfrL
μ～riθO×41θmIt, preferably 1100X1
The concentration of the feather-shaped alumina sol with a solid content of 0μ to 3θox3omμ is 0. θ/~θ, 2 f/l
, preferably 0.02 to θ,/g/l.

Particle size for colloidal silica! ~! θmμ, preferably 10-. Particles of granular shape of 20 mμ are used. An aqueous solution of colloidal silica that is either acidic or alkaline stabilized can be used, but acidic and stabilized aqueous solutions are preferred.

The concentration of colloidal silica is θ as solid content, θ3~/
, θy7t% preferably 0.7 to 0. ! t f/l is good. Similarly, a colloidal solution of acid-stable silica with such a concentration is usually pH 4t-6.The amounts of the aqueous solution containing alumina sol and the aqueous solution containing colloidal silica are calculated by the difference in area of the support/per 0-j. O can be expressed in degrees.

The method described above can be used to produce a dynamic membrane according to the method of the present invention. In this method, first, an aqueous solution of alumina sol is refluxed on a porous support. The reflux is
It is necessary to carry out the process under pressure, usually at ~0.7~/Om/sec, preferably at ~2~-m/sec.

The temperature of this alumina sol may be room temperature.

The reflux time varies depending on the conditions; 5 to 3
0 minutes is enough.

After this, the pressure is returned to normal pressure and the inside of the flow path is washed with water.

The aqueous solution of colloidal silica is then refluxed. Reflux is carried out under pressure, usually 2~''kg/caG, preferably '~''
j kg/e4 G, flow rate 0. / ~/ Om
/sac, preferably 0.2 to 2 m/see. The temperature of this colloidal silica aqueous solution may be room temperature.

The reflux time varies depending on the conditions, but may be 5 to 30 minutes.

After this, while still under pressure, pH/~3.5, preferably pH
/, Oh~λ,! Reflux the acid aqueous solution.

Specifically, an aqueous acid solution prepared with a strong acid such as sulfuric acid, nitric acid, or hydrochloric acid is used. Although the reflux time varies depending on various conditions, it may be 3θ minutes. This treatment promotes aggregation of silica particles and forms a strong dynamic film.

Subsequently, it is preferable that the mixture is further kneaded under pressure and the heated water is refluxed.

Heated water is usually 1yo~/θθ℃, preferably 7θ~
The temperature of 10θ℃ is used.

Reflux time varies depending on various conditions/! ~90 minutes is enough. By this method, it is possible to further strengthen the bond between the silica particles and create a dynamic kf shape with strong force and entanglement with the alumina particles and a high solute exclusion rate.

Thereafter, the pressure is returned to normal and the inside of the channel is washed with water, completing the formation of the DynaBac film.

It goes without saying that during the production of a dynamic membrane, one side of the porous support from which permeated water is discharged is always kept at normal pressure.

The thus obtained dynamic membrane has better performance in excluding polymeric substances than the dynamic membrane produced in the same manner as the aluminum production method.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples and does not exceed the gist of the present invention.

Example/Alumina sol (particle size: 220 ox, zomμ to 30θX 3Qmμ) was added as a solid content in water 301 on a ceramic porous negative support (surface pore diameter: about θ, /μ) of θ, 77d. 22% aqueous solution to a pressure of 20%
/dG, flow rate 0.1 m/BeC1 temperature -0°C, the mixture was refluxed for 20 minutes to form a film. Thereafter, the pressure was returned to normal and the inside of the channel was washed with water.

Next, colloidal silica (particle size: 10
A membrane was formed by refluxing an aqueous solution in which 69% (-20 mμ) was dissolved as a solid content at a pressure of 20/c9/cdG, a flow rate of O6 of fn/sec, and a temperature of -0°C for %2θ minutes. While keeping the pressure θ at 9/crl G, pH, 2,
The sulfuric acid aqueous solution at 21.20° C. was refluxed for 20 minutes, and then water was refluxed at the same pressure to wash and remove the sulfuric acid. Thereafter, the pressure was returned to normal, and the inside of the channel was washed with water to form a dynamic membrane.

Using the dynamic membrane thus produced, the pressure was -9/cdl G and the flow rate was 0. nim/eec
.

A 3% gelatin aqueous solution equivalent to JIsg building was passed through at a temperature of 0°C. The results are shown in Table-/.

After treatment, it was left under pressure (20 to 91 crlG) for 50
℃.

A dynamic membrane was produced and an aqueous gelatin solution was PMed in the same manner as in Example J, except that the heated water at temperatures of 20°C and 10°C was refluxed for 20 minutes.The results are shown in Table VC.

Table - / Comparative Example / A dynamic film was produced in the same manner as in the case of Shoriki Seisei, except that the step 1 to form a dynamic film of alumina sol was omitted.

Furthermore, the aqueous gelatin solution was filtered with Nbζb'c L as described in Example 1, and solutes were removed;
Ki/o was 2o, 7%.

Representative Patent Attorney Hase - 7 others Inside 0 shots by Takayuki Tanabe Inside 0 applicants Mitsubishi Kasei Techno Engineers Co., Ltd. 2-1-30 Shiba, Minato-ku, Tokyo

Claims (2)

[Claims] (1) Alumina sol is refluxed with an indenter on a porous support to form a membrane, colloidal silica is further refluxed with an indenter on top of the membrane to form a membrane, and then pg
The value is 3. A method for producing a dynamic membrane that involves refluxing an acid aqueous solution at a lower temperature. (2) A method for producing the implant according to claim 1, which comprises refluxing the acid aqueous solution using a pressurizer, and then refluxing heated water under pressure.