JPS63221815A - Manufacture of porous diaphragm - Google Patents

Abstract

PURPOSE:To manufacture a diaphragm of superior heat resistance and chemical resistance and with sharp and ultrafine average pore diameter distribution by using mixed sol of oxide or hydroxide of specific elements as a starting raw material of a film of porous carrier. CONSTITUTION:Mixed sol the respective oxide or hydroxide compounds of at least one element selected out of the groups of Si, Ti and Zr, Al and Na is applied on a porous carrier such as alumina or the like simply by the dipping or spraying method, or calcinated at 400 deg.C or lower, gels and coats the porous carrier. Then, the coated carrier is immersed simply in hot water, or hot water in an autoclave in the range of 80-500 deg.C, or being put in circulating heated water vapor, and calcined at 400-1,300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a porous diaphragm having a separation function.

[Prior art]

This type of porous diaphragm is used for gas separation, ultrafiltration, precision filtration, etc., but in recent years, demands for heat resistance and chemical resistance have become stronger depending on usage conditions, and ceramic powders and metal powders are molded and fired. A porous diaphragm has been developed. JP-A-60-129119 discloses a gas separation membrane that is an example of this type of porous diaphragm.

The separation membrane was invented by utilizing the excellent separation function of zeolite to obtain a membrane with excellent heat resistance and chemical resistance. A zeolite membrane is formed by precipitating crystals.

[Problem that the invention seeks to solve]

However, in the separation membrane, there is a limit to the average pore size of the zeolite membrane, or the pore size distribution is not sharp because of the pores formed between zeolite powder particles. Therefore, it is difficult to obtain a separation membrane with an ultra-fine average pore diameter of 10 to several 100 pores.

Therefore, the object of the present invention is to have excellent heat resistance and chemical resistance, and a sharp pore size distribution of 10 to several 100 λ.
The objective is to produce a porous diaphragm having an ultra-fine average pore diameter.

[Means for solving problems]

The present invention relates to a method for manufacturing such a porous diaphragm,
At least one element selected from the group of Si, Ti, and Zr and A! The mixed sol of each oxidation or hydroxide of Na and Na itself or after being calcined is coated on a porous support, the support is hydrothermally treated, and then dried and fired.

In the present invention, it is preferable that the Na component of the solid content in the mixed sol is 1 to 20 iv t% in terms of oxide, and the components of the (St, Tt, Zr) group are preferably 50 to 20 iv t%.
-t% or more, it is more preferable that the Aβ component is contained in an amount of 5 to 40 wt%. As starting materials for a mixed sol of these elements, alcoholates, chelates, salts, etc. of each element are preferred. Specific examples include aluminum isopropylate, aluminum butyrate, monobutoxyaluminum diisopropylate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate), and chlorides and nitrates of each of the above elements. , sulfates, and the like. A mixed sol can be obtained by hydrolyzing these, but it is preferable to add an acid during hydrolysis to adjust P)l to 1 to 5.

The mixed sol itself can be coated on a porous carrier by dipping or spraying, or it can be calcined at 400° C. or below to gel and adhere to the porous carrier. The coated porous support is hydrothermally treated in the range of 80-500°C by simply immersing it in hot water or hot water in an autoclave, or by placing it in flowing heated steam;
It is fired at a temperature of 300°C. When the mixing ratio of Si in the film is 50 to 70wt%, firing is performed at a relatively low temperature of up to 700°C, and when the mixing ratio is high, firing is performed at a relatively low temperature of up to 700°C.
It is preferable to bake at a high temperature of ℃ or higher.

As the porous carrier, an appropriate ceramic material such as alumina, silica-alumina, mullite, cordierite, zirconia, carbon, etc. is used, and the average pore diameter thereof is larger than the average pore diameter of the coating, for example, 0. ．．
The thickness is preferably about 1 to 10 μm.

[Action/effect of the invention]

In the porous diaphragm produced by the method of the present invention,
The film covering the support exhibits a pseudo-zeolite structure due to its composition, and the film has a pseudo-zeolite structure. It has an If function and is excellent in heat resistance and chemical resistance, but in particular, a mixed sol of oxidation or hydroxide of each element is used as a starting material for the film. The oxidized or hydroxide particles of each element in the mixed sol are extremely fine, have uniform particle sizes, and are in a uniformly mixed state.
Therefore, a coating using such a mixed sol as a starting material has ultrafine pore diameters and a sharp pore diameter distribution.

In addition, in the method of the present invention, it is preferable that the Na component contains 1 to 20 wt% in terms of oxide; if it is smaller than this value, uniform pores cannot be obtained, and if it is larger than the above value, However, it is not possible to obtain a material with uniform pores, and this also leads to a decrease in acid resistance.

Regarding hydrothermal treatment, the temperature is preferably in the range of 80 to 500°C,
If it is lower than this value, the hydrothermal treatment is insufficient, making it difficult to obtain a pseudo-zeolite structure and having poor thermal stability (and if it is higher than the above value, industrial operation becomes difficult. In the method of the present invention, In particular, add acid during hydrolysis to achieve a pH of 1~
When adjusted to 5, a stable sol solution and fine particles are formed, which is suitable for film formation. If the pH is lower than the above value, the sol will easily gel and cannot be passed through membrane formation, and if it is higher than the above value, colloidal particles will polycondense and become macromolecules, making it difficult to form membranes with fine pores. difficult.

The firing temperature is preferably in the range of 400 to 1,300°C. If lower than such value, heat resistance;
Sufficient corrosion resistance cannot be obtained, and furthermore, the residual carbide does not disappear and the release of the acid as an additive is insufficient. Further, when the value is higher than the above value, the fine particles forming the micropores grow due to sintering, and finally become vitrified and lose the membrane function.

The temperature for calcination of the mixed sol is preferably 400°C or lower, thereby compressing it into finer particles and increasing the interparticle bonding force by subsequent firing to obtain a film with fine pores. be able to.

〔Example〕

5i (QC) 1ρ4, 86 (OCJH, ), and water glass at 80 wt% in terms of oxide of each metal element, 15-
t % and 5 wt %, added to 80° C. hot water and hydrolyzed for 1 hour, and then added nitric acid so that the pH was 3 to obtain a mixed sol. The obtained mixed sol was supported on an α-alumina pipe with an outer diameter of 10 N, an inner diameter of 8 N, and an average pore diameter of 1 μm, and after drying, it was heated in an autoclave for 200 min.
It is hydrothermally treated by immersing it in hot water at ℃ for 12 hours. Next, this pipe was dried and fired at 650°C for 1 hour, and then heated at 80°C.
A porous diaphragm was obtained by washing with hot water at .degree. C. for 1 hour. The average pore diameter of the resulting porous diaphragm was 10λ. Note that the average pore diameter is measured by a gas adsorption method.

[Example 2] Zr(QC
, Hl)3, and T1(QC, H7), a porous diaphragm was produced in the same manner as in the same example. The average pore diameter (gas adsorption method) of each membrane obtained was 108.

[Example 3] Except for Example 1, in which the oxide equivalent values of each metal element (Si, Aβ, Na) were set to 95-L%, 4wt%, and 1-t%, and the firing temperature was set to 1,200°C. produced a porous diaphragm in the same manner as in the same example. The average pore diameter in the resulting membrane of each diaphragm was 100A. Note that the average pore diameter is measured by a gas adsorption method.

The porous diaphragm manufactured in each of the above examples was placed in a flow-through gas separation device, and IIz50voA%, Nz50ν
A separation test was conducted using a 1% O mixed gas at room temperature and a supply pressure of 2 to 20 kg/-. Hl in the gas on the permeate side is 6
It was confirmed that it was concentrated to 5 to 61 vol% and had excellent selective permeability (separation function). Also, each diaphragm has 4
Heat treated in the atmosphere at 00°C for 100 hours, P11=
When we conducted the above separation test on samples that had been immersed in HCl solution at a temperature of 90℃ for 200 hours at pH=14 and for 200 hours on samples that had been immersed in a NaOH solution at a temperature of 90℃ at pH=14, we found that the separation function did not change before and after these treatments. There were almost no changes.

Claims (6)

[Claims] (1) A mixed sol of at least one element selected from the group of Si, Ti, and Zr and each oxidation or hydroxide of Al and Na is coated on a porous support by itself or after calcining. A method for producing a porous diaphragm, which comprises hydrothermally treating a carrier, followed by drying and firing. (2) The manufacturing method according to claim 1, wherein the solid content of the mixed sol contains 1 to 20 wt% of Na as an oxide. (3) The manufacturing method according to claim 1 or 2, wherein the mixed sol uses an alcoholate, chelate, or salt of each of the elements as a starting material. (4) Claim 1: The mixed sol is obtained by adding an acid to a solution of the starting raw materials and hydrolyzing the same raw materials.
2. The manufacturing method according to item 2, item 3, or item 3. (5) The manufacturing method according to claim 1, 2, 3, or 4, wherein the hydrothermal treatment is performed with water or steam at 80 to 500°C. (6) The manufacturing method according to claim 1, 2, 3, 4, or 5, wherein the firing temperature is 400 to 1,300°C.