JP2010253442A - Method of concentrating particulate dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of concentrating particulate dispersion, which can be executed by a simple apparatus and can continuously treat the particulate dispersion of a relatively high concentration. <P>SOLUTION: In the method of concentrating the particulate dispersion, the particulate dispersion which contains zeolite particles or silica particles in an average particle size of 1-1,000 nm for 0.01-30 volume% and whose flow rate is 20-200 L/min/m<SP>2</SP>is supplied to a fixed ultrafiltration membrane having a pore diameter of 1-100 nm by a pressure of 0.03-1.0 MPa. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for concentrating a fine particle dispersion.

Fine particle dispersions are used in a wide range of fields such as electronic materials, catalysts, heat ray shielding, and coating agents.
The average particle size of the fine particles in the fine particle dispersion is usually several tens of nm. However, when the average particle size is about 1 to 100 nm, there is a problem that it takes a very long time to separate the liquid and the fine particles in dead end filtration. It was.

  For the concentration of the fine particle dispersion, a centrifuge is usually used. However, the centrifuge is difficult to increase in size and cannot be operated continuously, so that a large amount of the fine particle dispersion cannot be processed.

  When the fine particle dispersion is concentrated using a reverse osmosis membrane or an ultrafiltration membrane, the substance to be separated is usually in the order of molecules or polymers in the fine particle dispersion, and the concentration is usually 1% or less. is there. If the particle size of the fine particles exceeds 1 μm, normal filtration can be used.

  Several methods using the reverse osmosis membrane or ultrafiltration membrane have been proposed (Patent Document 1, and Non-Patent Document 1 and Non-Patent Document 2), but the fine particles and the liquid are completely separated, and the separation target There is no disclosure of a concentration method in which the particle size of the fine particles is nano-order (1 to 1000 nm).

US Pat. No. 6,521,562

From Zeolites to Porous MOF Materials the 40th Anniversary of International Zeolite Conference, R.Xu, Z.Gao, J.Chen and W.Yan (Editors), Elsevier, 242-249 (2007) J. Am. Chem. Soc., 128, 3190-3197 (2006)

  An object of the present invention is to provide a method for concentrating a fine particle dispersion which can be carried out with a simple apparatus and can continuously process a relatively high concentration fine particle dispersion.

According to the present invention, the following concentration method is provided.
1. A fine particle dispersion having a flow rate of 20 to 200 L / min / m ² containing 0.01 to 30% by volume of zeolite particles or silica particles having an average particle diameter of 1 to 1000 nm is applied at a pressure of 0.03 to 1.0 MPa. A method for concentrating a fine particle dispersion supplied to a fixed ultrafiltration membrane having a pore diameter of ˜100 nm.
2. A fine particle dispersion containing 0.01 to 30% by volume of zeolite particles or silica particles having an average particle diameter of 1 to 1000 nm is a pressure of 0.03 to 1.0 MPa and a peripheral speed of 1.5 to 12 m / s. A method for concentrating a fine particle dispersion to be supplied to a disk-shaped rotary ultrafiltration membrane having a pore diameter of ˜100 nm.
3. 3. The method for concentrating a fine particle dispersion according to 1 or 2, wherein the zeolite particles are MFI type zeolite particles.

  According to the present invention, it is possible to provide a method for concentrating a fine particle dispersion which can be carried out with a simple apparatus and can continuously process a relatively high concentration fine particle dispersion.

It is a system diagram of the concentration method of the fine particle dispersion according to an embodiment of the present invention. It is a system diagram of the concentration method of the fine particle dispersion used in Examples 1-6. It is a system diagram of the concentration method of the fine particle dispersion used in Examples 7 and 8.

The method for concentrating a fine particle dispersion of the present invention comprises a fine particle dispersion having a flow rate of 20 to 200 L / min / m ² containing 0.01 to 30% by volume of zeolite particles or silica particles having an average particle diameter of 1 to 1000 nm. , And supplied to a fixed ultrafiltration membrane having a pore size of 1 to 100 nm at a pressure of 0.03 to 1.0 MPa.

  Moreover, the concentration method of the fine particle dispersion of the present invention is a fine particle dispersion containing 0.01 to 30% by volume of zeolite particles or silica particles having an average particle diameter of 1 to 1000 nm at a pressure of 0.03 to 1.0 MPa. It supplies to the rotation ultrafiltration membrane which has a hole diameter of 1-100 nm whose peripheral speed is 1.5-12 m / s.

When the particle size of the contained fine particles is nano-order (1 to 1000 nm), the fine particle dispersion is usually difficult to separate into solid and liquid, but by using the method for concentrating fine particle dispersion of the present invention, it is continuous with a simple apparatus. Then, it can be concentrated at a flow rate above a certain level (for example, 1 × 10 ⁻⁶ m ³ / m ² / s or more in permeate flow rate).
Further, by using the method for concentrating fine particle dispersion of the present invention, the fine particle dispersion can be concentrated to, for example, 20 to 30% by volume.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram of a method for concentrating a fine particle dispersion according to an embodiment of the present invention.
As shown in FIG. 1, the fine particle dispersion is supplied from the dispersion supply tank 10 to the membrane separation module 30 by the transport pump 20. In the membrane separation module 30, the fine particle dispersion is filtered, the filtrate is discharged from the discharge path 40, and the fine particle concentrate is returned from the circulation path 50 to the dispersion supply tank 10 through the valve 60.

The fine particles contained in the fine particle dispersion used in the concentration method of the present invention (hereinafter sometimes simply referred to as the fine particle dispersion of the present invention) are zeolite particles or silica particles, preferably MFI type zeolite particles.
The average particle diameters of the zeolite particles and the silica particles are each 1 to 1000 nm, preferably 10 to 500 nm. This average particle diameter is a value obtained using a dynamic scattering method, and can be measured, for example, by using ELS-Z2 (manufactured by Otsuka Electronics Co., Ltd.).
The synthesized zeolite particles are usually 10 to 1000 nm.

The content of fine particles in the fine particle dispersion of the present invention is 0.01 to 30% by volume, preferably 0.1 to 10% by volume. When the content of fine particles exceeds 30% by volume, the flow rate of the permeate may be reduced.
In the case where the fine particle dispersion is circulated as in the system of FIG. 1, the concentration of the first fine particle dispersion to be processed and the concentration of concentrated water after filtration may be low. For example, the washing liquid may be added only for the filtrate, and the washing may be performed without increasing the concentration.

  As a dispersion solvent for the fine particle dispersion of the present invention, for example, water; alcohols such as ethanol and methanol can be used.

  The fine particle dispersion of the present invention can be prepared, for example, by adding a dispersion solvent such as water to a commercially available silica dispersion to obtain a predetermined concentration. Moreover, the reaction completion liquid of zeolite can also be used as it is as the fine particle dispersion of the present invention.

In the concentration method of the present invention, the fine particle dispersion of the present invention is supplied to the ultrafiltration membrane at a pressure of 0.03 to 1.0 MPa, and preferably the fine particle dispersion of the present invention is limited to a pressure of 0.03 to 0.2 MPa. Supply to the outer membrane. Even when the supply pressure of the fine particle dispersion exceeds 1.0 MPa, the amount of permeate cannot be increased.
In the case of the system shown in FIG. 1, the supply pressure of the fine particle dispersion can be adjusted by, for example, the transport pump 20 and / or the valve 60.

The pore size of the ultrafiltration membrane used in the concentration method of the present invention is 1 to 100 nm. The pore size of the ultrafiltration membrane depends on the particle size of the fine particles contained in the fine particle dispersion to be treated. Usually, since the particles have a particle size distribution, the pore size of the ultrafiltration membrane is set smaller than the average particle size of the fine particles.
When the pore size of the ultrafiltration membrane is less than 1 nm, the permeate flow rate may decrease and the processing time may be prolonged. On the other hand, when the pore size of the ultrafiltration membrane is more than 100 nm, fine particles may pass through.

In the concentration method of the present invention, a fixed ultrafiltration membrane or a disk-like rotary filtration membrane is used.
As the ultrafiltration membrane used in the concentration method of the present invention, for example, a flat membrane or an annular membrane can be used, and these membranes may be a module type. The membrane area of the filtration membrane can be adjusted by the throughput of the fine particle dispersion, and when the ultrafiltration membrane requires a large area, an annular membrane module type is preferable.
For example, since zeolite synthesis is often carried out with high alkalinity, it is desirable that the ultrafiltration membrane be alkali resistant.

When the concentration method of the present invention is carried out using a fixed ultrafiltration membrane, the fine particle dispersion of the present invention is supplied to the fixed ultrafiltration membrane at a flow rate of 20 to 200 L / min / m ² per membrane area.
When the flow rate is less than 20 L / min / m ² , the particle peeling effect due to the flow may not be obtained. On the other hand, when the flow rate exceeds 200 L / min / m ² , the pressure increases and the load on the transport pump may increase.

When the concentration method of the present invention is carried out using a disk-shaped rotary filtration membrane, the disk-shaped rotary filtration membrane is set to 1.5 to 12 m / s, preferably 5 to 10 m / s at a peripheral speed based on the outer diameter. The fine particle dispersion of the invention is fed to a disc rotating filtration membrane.
When the peripheral speed is less than 1.5 m / s, there is a possibility that the effect of removing particles by rotation cannot be obtained. On the other hand, when the peripheral speed is more than 12 m / s, there is a possibility that cavitation, shaft vibration, and deterioration of the durability of the film may become problems.

The fixed ultrafiltration membrane peels off the fine particles by the flow of the fluid, whereas the disc-shaped rotary filtration membrane rotates the membrane itself to peel off the fine particles.
Specific examples of the disk-shaped rotary filtration membrane include R-Fine manufactured by Kotobuki Industries Co., Ltd.

  In the concentration method of the present invention, for example, the discharge path, the circulation path, and the membrane separation module of the system shown in FIG. 1 are not particularly limited as long as they can withstand pressure and impurities are not mixed into the fine particle dispersion. The discharge path, the circulation path, and the membrane separation module are usually made of stainless steel or resin.

Example 1
The fine particle dispersion was concentrated using the fine particle dispersion concentration system shown in FIG.
Specifically, the fine particle dispersion was supplied from the dispersion supply tank 10 to the membrane separation module 30 by the transport pump 20. The fine particle dispersion is filtered in the membrane separation module 30, the filtrate is discharged from the discharge path 40, the concentrated liquid of the fine particle dispersion is passed through the valve 60 and the flow meter 70, and returned from the circulation path 50 to the dispersion supply tank 10. It was.
The dispersion supply tank 10 was temperature-controlled with a thermostat 90 while stirring with a stirrer 80. Further, the permeate flow rate of the concentrate was measured with a flow meter 70, and the membrane separation pressure in the membrane separation module 30 of the concentrate was measured with a gauge 100.

Colloidal silica having an average particle diameter of 11 nm (SI-30, manufactured by Catalyst Chemical Industry Co., Ltd.) was used as the fine particles, and water was used as the dispersion solvent to prepare a fine particle dispersion having a concentration of 1.2% by volume. .
The membrane separation module 30 is a thin film flow type flat membrane test cell C10-T (manufactured by Nitto Denko Corporation), and has a molecular weight cut-off of 50,000 (membrane pore diameter is about 5 nm) on the filtration membrane of the membrane separation module 30. Using an ultrafiltration membrane (NTU-3150, manufactured by Nitto Denko Corporation), the fine particle dispersion was supplied to the ultrafiltration membrane at a flow rate of 140 L / min / m ² and a pressure of 0.12 MPa, and the permeation flow rate was measured. The results are shown in Table 1.

Example 2
The fine particle dispersion was concentrated and the permeate flow rate was measured in the same manner as in Example 1 except that colloidal silica having an average particle size of 47 nm (SI-45P, manufactured by Catalyst Chemical Industry) was used for the fine particles of the fine particle dispersion. . The results are shown in Table 1.

Example 3
The fine particle dispersion was concentrated and the permeation flow rate was measured in the same manner as in Example 1 except that colloidal silica (manufactured by Catalyst Kasei Kogyo, SI-80P) having an average particle diameter of 80 nm was used for the fine particles of the fine particle dispersion. . The results are shown in Table 1.

尚、実施例１の透過流量１．７×１０^−５ｍ^３／ｍ^２／ｓは、換算すると１．０Ｌ／ｍｉｎ／ｍ^２であり、実施例２の透過流量７．５×１０^−６ｍ^３／ｍ^２／ｓは、換算すると０．４５Ｌ／ｍｉｎ／ｍ^２であり、実施例３の透過流量６．０×１０^−６ｍ^３／ｍ^２／ｓは、換算すると０．３６Ｌ／ｍｉｎ／ｍ^２である。

Note that the flux ^{1.7 × 10 -5 m 3 / m} 2 / s Example 1, when converted was 1.0 L / min / ^{m 2,} permeation of Example 2 flow rate 7.5 × ^{10 -6} m ³ / m ² / s is converted to 0.45 L / min / m ² , and the permeation flow rate of Example 3 is 6.0 × 10 ⁻⁶ m ³ / m ² / s is converted to 0.36 L / s. min / m ² .

Example 4
Based on the method disclosed in ZEOLITES, 14, 557-567 (1994), 40 g of 10% NaOH aqueous solution (manufactured by Wako Pure Chemical Industries), 2188 g of purified water (manufactured by Wako Pure Chemical Industries), TPAOH (tetrapropyl ammonium hydroxide, manufactured by SACHEM) ) 2000 g and TEOS (tetraethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) 2553 g were put into a 10 L stirring tank and reacted with stirring at 25 ° C. for 24 hours and 100 ° C. for 48 hours, respectively, and zeolite fine particles having an average particle size of 100 nm A zeolite fine particle dispersion (zeolite reaction liquid) having a concentration of 10 vol% was prepared.
The composition (molar ratio) of the obtained zeolite fine particle dispersion was as follows.
TPAOH / SiO2 / H2O / EtOH = 8/25/338/100

  The fine particle dispersion was concentrated and the permeate flow rate was measured in the same manner as in Example 1 except that the fine particle dispersion prepared above was used. The results are shown in Table 2.

Example 5
The fine particle dispersion was concentrated and the permeate flow rate was measured in the same manner as in Example 4 except that the concentration of the fine particle dispersion was changed to 5% by volume. The results are shown in Table 2.

Example 6
The fine particle dispersion was concentrated and the permeate flow rate was measured in the same manner as in Example 4 except that the concentration of the fine particle dispersion was 2.5% by volume. The results are shown in Table 2.

尚、実施例４の透過流量１．２×１０^−６ｍ^３／ｍ^２／ｓは、換算すると０．０７２Ｌ／ｍｉｎ／ｍ^２であり、実施例５の透過流量２．８×１０^−６ｍ^３／ｍ^２／ｓは、換算すると０．１７Ｌ／ｍｉｎ／ｍ^２であり、実施例６の透過流量５．０×１０^−６ｍ^３／ｍ^２／ｓは、換算すると０．３０Ｌ／ｍｉｎ／ｍ^２である。

Note that the flux ^{1.2 × 10 -6 m 3 / m} 2 / s Example 4, when converted was 0.072L / min / ^{m 2,} permeation of Example 5 flow 2.8 × ^{10 -6} m ³ / m ² / s is 0.17 L / min / m ² in terms of conversion, and the permeation flow rate of 5.0 × 10 ⁻⁶ m ³ / m ² / s in Example 6 is 0.30 L / in in terms of conversion. min / m ² .

Example 7
The fine particle dispersion was concentrated using the fine particle dispersion concentration system shown in FIG.
Specifically, the fine particle dispersion was supplied from the dispersion supply tank 10 to the membrane separation module 30 by the transport pump 20. The fine particle dispersion was filtered in a membrane separation module 30 including a disk-shaped rotary filtration membrane, and the concentrated solution and the filtrate were separated from each other. The separated concentrated solution and filtrate were each controlled by the valve 60 and partly returned to the dispersion supply tank 10 and the rest was discharged.

  The membrane separation module 30 is R-Fine (manufactured by Kotobuki Kogyo Co., Ltd.). A ceramic membrane having a pore diameter of 7 nm is used as the filtration membrane of the membrane separation module 30, and this ceramic membrane is 740 rpm (peripheral speed: 5.9 m / min). While rotating at s), the zeolite fine particle dispersion having an average particle diameter of 10 nm and a concentration of 10% by volume prepared in Example 4 was supplied at a pressure of 0.1 MPa, and the permeation flow rate was measured. The results are shown in Table 3.

Example 8
The fine particle dispersion was concentrated and the permeate flow rate was measured in the same manner as in Example 7 except that the concentration of the fine particle dispersion was changed to 5% by volume. The results are shown in Table 3.

尚、実施例７の透過流量３．１×１０^−６ｍ^３／ｍ^２／ｓは、換算すると０．１９Ｌ／ｍｉｎ／ｍ^２であり、実施例８の透過流量５．３×１０^−６ｍ^３／ｍ^２／ｓは、換算すると０．３２Ｌ／ｍｉｎ／ｍ^２である。

Note that the flux ^{3.1 × 10 -6 m 3 / m} 2 / s Example 7, when converted is 0.19L / min / ^{m 2,} permeation of Example 8 flow 5.3 × ^{10 -6} When converted, m ³ / m ² / s is 0.32 L / min / m ² .

  The fine particle dispersion concentrated by the concentration method of the present invention can be used in a wide range of fields such as electronic materials, catalysts, heat ray shielding, and coating agents.

10 Dispersion Supply Tank 20 Transport Pump 30 Membrane Separation Module 40 Discharge Channel 50 Circulation Channel 60 Valve 70 Flow Meter 80 Stirrer 90 Thermostat 100 Gauge

Claims (3)

A fine particle dispersion having a flow rate of 20 to 200 L / min / m ² containing 0.01 to 30% by volume of zeolite particles or silica particles having an average particle diameter of 1 to 1000 nm is applied at a pressure of 0.03 to 1.0 MPa. A method for concentrating a fine particle dispersion supplied to a fixed ultrafiltration membrane having a pore diameter of ˜100 nm.   A fine particle dispersion containing 0.01 to 30% by volume of zeolite particles or silica particles having an average particle diameter of 1 to 1000 nm is a pressure of 0.03 to 1.0 MPa and a peripheral speed of 1.5 to 12 m / s. A method for concentrating a fine particle dispersion to be supplied to a disk-shaped rotary ultrafiltration membrane having a pore diameter of ˜100 nm.   The method for concentrating a fine particle dispersion according to claim 1 or 2, wherein the zeolite particles are MFI type zeolite particles.

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