WO2022068109A1

WO2022068109A1 - High-flux anti-pollution ceramic filter membrane and preparation method therefor

Info

Publication number: WO2022068109A1
Application number: PCT/CN2020/140300
Authority: WO
Inventors: 丘助国; 洪昱斌; 方富林; 蓝伟光
Original assignee: 三达膜科技（厦门）有限公司
Priority date: 2020-09-29
Filing date: 2020-12-28
Publication date: 2022-04-07
Also published as: CN114307664B; CN114307664A

Abstract

Disclosed in the present invention are a high-flux anti-pollution ceramic filter membrane and a preparation method therefor. The ceramic filter membrane has a pure water flux of 2600-3200 LMH under a pressure of 0.1 MPa, comprises a ceramic membrane support body and a transition membrane layer and a filter membrane layer which are provided on the surface of the ceramic membrane support body, and has a 48h stable flux of 190-240 LMH for a 1wt% soybean protein dispersion under the pressure of 0.1 MPa. The filter membrane layer prepared in the present invention has good flatness, no cavity defect on the membrane surface, a high membrane flux, and a strong anti-pollution capability; the preparation method in the present invention can prevent the transition membrane layer from collapsing into the inside of the support body, thereby improving the flatness of the membrane layer, reducing membrane resistance, and increasing the membrane flux and improving anti-pollution performance.

Description

A kind of high-flux anti-pollution ceramic filter membrane and preparation method thereof

technical field

The invention belongs to the technical field of membrane separation materials, and in particular relates to a high-flux anti-pollution ceramic filter membrane and a preparation method thereof.

Background technique

Membrane technology has been highly valued by countries all over the world in recent years. With the large-scale promotion and application of membrane and membrane technology, more and more countries have placed it in an important position in scientific and technological innovation and national economic development. Among many membrane materials, ceramic membranes have strong anti-microbial ability; high temperature resistance; narrow pore size distribution, high separation efficiency, good chemical stability, acid resistance, alkali resistance, organic solvent resistance, high mechanical strength, and can be backwashed; It has been widely used in food industry, biological engineering, environmental engineering, chemical industry, petrochemical industry, metallurgical industry and other fields.

Commercial ceramic membranes usually have a structure of two or more layers (porous support layer, 0 layer, 1 layer or multi-layer transition membrane layer and separation membrane layer), which are distributed asymmetrically. The support is usually fired from large-sized ceramic oxide particles of 5-100 μm, and the formed microporous structure has a pore size of about 1-30 μm. Then, a transition membrane layer with a gradually decreasing pore size is formed by sintering metal oxide particles with a gradually decreasing particle size on the support, and finally a separation membrane layer material with a corresponding particle size is used to prepare a pore size ranging from 0.8 nm to 1 μm. Filtration accuracy covers microfiltration, ultrafiltration, nanofiltration grade separation membrane layers.

However, in the process of preparing the existing membrane layer, due to the uneven distribution of the pore size of the support body and the different pore sizes, the particles of the transition membrane layer usually cannot form a good overlapping structure on the surface of the support body, but collapse into the support body. Internally, the porosity of the support is greatly reduced, the membrane flux is reduced, and the membrane resistance is improved. And due to the collapse of the bottom layer, the final separation membrane layer is uneven, the membrane flatness is poor, the membrane layer is easy to wear, and the anti-pollution performance is poor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of the prior art and provide a high-flux anti-pollution ceramic filter membrane.

Another object of the present invention is to provide a method for preparing the above-mentioned high-flux anti-pollution ceramic filter membrane.

The technical scheme of the present invention is as follows: a high-flux anti-pollution ceramic filter membrane, comprising a ceramic membrane support body and a transition membrane layer and a filter membrane layer arranged on the surface of the ceramic membrane accordingly, the pore size of the ceramic membrane support body is 5-30 μm; the porosity of the filtration membrane layer is 36-40%, the surface of the membrane layer is smooth, the filtration accuracy of the prepared ceramic membrane is 100 nm, and the 1wt% soybean protein dispersion under 0.1MPa pressure is stable for 48h The flux is 190-240LMH.

In a preferred embodiment of the present invention, the material of the ceramic membrane support body is alumina or silicon carbide.

In a preferred embodiment of the present invention, the porosity of the filter membrane layer is 36-40%.

In a preferred embodiment of the present invention, the thickness of the filter membrane layer is 25-35 μm.

Further preferably, the material of the ceramic membrane support body is alumina, and its pore size is 5-10 μm.

Further preferably, the material of the ceramic membrane support body is silicon carbide, and its pore size is 10-30 μm.

The above-mentioned preparation method of high-flux anti-pollution ceramic filter membrane is characterized in that: comprising the following steps:

(1) Coating activated carbon powder dispersion on the ceramic membrane support, then drying to form an activated carbon membrane layer with a thickness of 3-6 μm;

(2) coating the transition film layer coating liquid on the above-mentioned activated carbon film layer with the dip coating method, and then drying and sintering to form the transition film layer;

(3) Coat the filter membrane layer coating liquid on the transition membrane layer by the dip coating method, and then dry and sinter to form the ceramic filter membrane layer.

In a preferred embodiment of the present invention, the particle size of the activated carbon powder in the activated carbon powder dispersion liquid is 0.5-1 μm.

Further preferably, the concentration of the activated carbon powder dispersion liquid is 1-3 wt%.

In a preferred embodiment of the present invention, the drying temperature in the step (1) is 105-115° C., and the time is 24-48 h.

In a preferred embodiment of the present invention, the drying temperature in the step (2) is 105-115°C, the time is 24-48h, the sintering temperature is 1500-1650°C, and the time is 2-6h.

In a preferred embodiment of the present invention, the drying temperature in the step (3) is 105-115°C, the time is 24-72h, the sintering temperature is 1320-1380°C, and the time is 2.5-3.5h.

The beneficial effects of the present invention are:

1. The filtration membrane layer of the present invention has good flatness, no void defects on the membrane surface, high membrane flux, and strong anti-pollution ability.

2. The preparation method of the present invention prevents the transition membrane layer from collapsing into the support body by adding an activated carbon support layer, thereby improving the smoothness of the membrane layer, reducing the membrane resistance, and improving the membrane flux and anti-pollution performance.

Detailed ways

The technical solutions of the present invention will be further illustrated and described below through specific embodiments.

Example 1:

The activated carbon powder (0.8 μm) dispersion (2wt%) was coated with an activated carbon film layer with a thickness of 6 μm on the alumina ceramic membrane support with a pore size of 5-10 μm by dip coating method, and the above activated carbon film layer was heated at 105 ° C. After drying for 24 hours, a layer of aluminum oxide (D50=3um) transition film layer with a thickness of 60 μm was coated on the activated carbon film layer by dip coating method. After drying at 105 °C for 24 hours, the above activated carbon film layer and transition film layer were After sintering at 1600 °C for 3 hours, an alumina filter layer with a thickness of 30 μm was prepared by the dip coating method. After drying at 105 °C for 24 hours, sintered at 1350 °C for 3 hours, the final porosity was 38% and the filtration accuracy was 100nm. Ceramic Membrane. The 100nm ceramic filtration membrane prepared in this example has good flatness of the filtration membrane layer, no void defects on the membrane surface, and the membrane pure water flux reaches 2600LMH under 0.1Mpa pressure, which is 57% higher than that of the ceramic membrane prepared in Comparative Example 1. Using soybean protein dispersion (0.1MPa, 1wt%) to conduct anti-fouling test, its 48h operating flux is stable at 220LMH, which is 69% higher than that of conventional ceramic membranes.

Example 2

The activated carbon powder (0.5μm) dispersion (3wt%) was coated with a layer of activated carbon film with a thickness of 4μm on a silicon carbide ceramic membrane support with a pore size of 10-15μm by dip coating method, and the above activated carbon film layer was heated at 105 ° C. After drying for 24 hours, a layer of silicon carbide (D50=3.5um) transition film with a thickness of 30 μm was coated on the activated carbon film by dip coating method. After drying at 105°C for 24 hours, the above activated carbon film and transition film After the layer was sintered at 1500 °C for 2 hours, an alumina filter membrane layer with a thickness of 25 μm was prepared by the dip coating method. %, a ceramic membrane with a filtration accuracy of 100 nm. The 100nm ceramic filtration membrane prepared in this example has good flatness of the filtration membrane layer, no void defects on the membrane surface, and the membrane pure water flux reaches 2800LMH under 0.1Mpa pressure, which is 86% higher than that of the ceramic membrane prepared in Comparative Example 6. Using soybean protein dispersion (0.1MPa, 1wt%) to conduct anti-fouling test, its 48h operating flux is stable at 238LMH, which is 64% higher than that of conventional ceramic membranes.

Example 3

The activated carbon powder (1 μm) dispersion (3wt%) was coated with a layer of activated carbon film with a thickness of 6 μm on a silicon carbide ceramic membrane support with a pore size of 15-30 μm by the dip coating method, and the activated carbon film layer was baked at 115 ° C. After drying for 48 hours, a layer of silicon carbide (D50=4.2um) transition film layer with a thickness of 80 μm was coated on the activated carbon film layer by dip coating method. After drying at 115 °C for 48 hours, the above activated carbon film layer and transition film layer were Sintered at 1650 °C for 6 h; then used the dip coating method to prepare an alumina filter membrane with a thickness of 35 μm. After drying the above membrane at 115 °C for 72 h, sintered at 1380 °C for 3.5 h, the final prepared porosity was 36%. Ceramic membrane with filtration accuracy of 100nm. The 100nm ceramic filtration membrane prepared in this example has good flatness of the filtration membrane layer, no void defects on the membrane surface, and the membrane pure water flux reaches 3200LMH under the pressure of 0.1Mpa, which is 79% higher than that of the ceramic membrane prepared in Comparative Example 7. Using soybean protein dispersion (0.1MPa, 1wt%) to conduct anti-fouling test, its 48h operating flux is stable at 195LMH, which is 74% higher than that of conventional ceramic membranes.

Comparative Example 1

A layer of alumina (D50=3um) transition film layer with a thickness of 60 μm was coated on the alumina ceramic membrane support with a pore size of 5-10 μm by the dip coating method, and after drying at 105 ° C for 24 hours, the above transition film layer was After sintering at 1600 °C for 3 hours, a 30 μm thick alumina filter layer was prepared by dip coating method, dried at 105 °C for 24 hours, and then sintered at 1350 °C for 3 hours. Ceramic Membrane. The 100nm ceramic filtration membrane prepared in this comparative example has poor surface flatness, and the membrane pure water flux is 1650LMH under 0.1Mpa pressure. The anti-pollution test was carried out with soybean protein dispersion (0.1MPa, 1wt%), and its 48h operation was smooth. The amount is stable at 130LMH.

Comparative Example 2

The activated carbon powder (1.5μm) dispersion (2wt%) was coated with an activated carbon film layer with a thickness of 10μm on the alumina ceramic membrane support with a pore size of 5-10μm by the dip coating method, and the above activated carbon film layer was heated at 105 ° C. After drying for 24 hours, a layer of aluminum oxide (D50=3um) transition film layer with a thickness of 60 μm was coated on the activated carbon film layer by dip coating method. After drying at 105 °C for 24 hours, the above activated carbon film layer and transition film layer were After sintering at 1600 °C for 3 hours, the transition film layer fell off seriously, and the separation film layer could not be formed. The activated carbon powder particles were too coarse, and the corresponding activated carbon film layer was too thick.

Comparative Example 3

The activated carbon powder (0.3 μm) dispersion (2wt%) was coated with an activated carbon film layer with a thickness of 1 μm on the alumina ceramic membrane support with a pore size of 5-10 μm by the dip coating method, and the above activated carbon film layer was heated at 105 ° C. After drying for 24 hours, a layer of aluminum oxide (D50=3um) transition film layer with a thickness of 60 μm was coated on the activated carbon film layer by dip coating method. After drying at 105 °C for 24 hours, the above activated carbon film layer and transition film layer were After sintering at 1600 °C for 3 hours, a 30 μm thick alumina filter layer was prepared by dip coating method, dried at 105 °C for 24 hours, and then sintered at 1350 °C for 3 hours. Alumina ceramic membrane. The 100nm alumina ceramic filter membrane prepared in this comparative example has poor surface flatness, and the membrane pure water flux is 1760LMH under 0.1Mpa pressure. The anti-pollution test was carried out with soybean protein dispersion (0.1MPa, 1wt%), and its 48h The operating flux is stable at 140LMH.

Comparative Example 4

The activated carbon powder (0.8 μm) dispersion (4wt%) was coated with an activated carbon film layer with a thickness of 20 μm on the alumina ceramic membrane support with a pore size of 5-10 μm by the dip coating method (the concentration of the activated carbon dispersion is too high, the corresponding The activated carbon film layer is too thick), after drying the above activated carbon film layer at 105 ℃ for 24 hours, a layer of alumina (D50=3um) transition film layer with a thickness of 60 μm is applied on the activated carbon film layer by dip coating method, 105 After drying at ℃ for 24 hours, the above activated carbon membrane layer and transition membrane layer were sintered at 1600 ℃ for 3 hours, the transition membrane layer fell off seriously, and the separation membrane layer could not be further formed.

Comparative Example 5

The activated carbon powder (0.8 μm) dispersion (0.5 wt%) was coated with an activated carbon film layer with a thickness of 3 μm on the alumina ceramic membrane support with a pore size of 5-10 μm by the dip coating method, and the above activated carbon film layer was placed at 105 . After drying at ℃ for 24 hours, a layer of alumina (D50=3um) transition film layer with a thickness of 60 μm was coated on the activated carbon film layer by dip coating method, and after drying at 105 ℃ for 24 hours, the above activated carbon film layer and transition film After the layer was sintered at 1600 °C for 3 hours, a 30 μm thick alumina filter layer was prepared by dip coating method, dried at 105 °C for 24 hours, and then sintered at 1350 °C for 3 hours. The final prepared porosity was 38% and the filtration accuracy was 100nm ceramic membrane. The 100nm ceramic filter membrane prepared in this example has some hole defects on the surface of the filter membrane, and the pure water flux of the membrane is 1870LMH under 0.1Mpa pressure. The 48h running flux was stable at 155LMH.

Comparative Example 6

A silicon carbide (D50=3.5um) transition film layer with a thickness of 30 μm is coated on the silicon carbide ceramic membrane support with a pore size of 10-15 μm by the dip coating method, and after drying at 105 ° C for 24 hours, the above transition film layer is After sintering at 1500°C for 2h, a 25μm-thick alumina filter film was prepared by dip coating method. After drying the above film at 105°C for 24h, sintered at 1320°C for 2.5h, the final porosity was 40%. , The filtration precision is 100nm ceramic membrane. The 100nm alumina ceramic filtration membrane prepared in this comparative example has poor membrane flatness, and the membrane pure water flux is 1500LMH under 0.1Mpa pressure. Soy protein dispersion (0.1MPa, 1wt%) is used for anti-pollution test, and its 48h The operating flux is stable at 145LMH.

Comparative Example 7

A silicon carbide (D50=4.2um) transition film layer with a thickness of 80 μm is coated on a silicon carbide ceramic membrane support with a pore size of 15-30 μm by the dip coating method, and after drying at 115 ° C for 48 hours, the above transition The membrane layer was sintered at 1650 °C for 6 hours; then an alumina filter membrane layer with a thickness of 35 μm was prepared by the dip coating method. After drying the above membrane layer at 115 °C for 72 hours, sintered at 1380 °C for 3.5 hours. The final prepared porosity was 36 %, a ceramic membrane with a filtration accuracy of 100 nm. The 100nm ceramic filtration membrane prepared in this example has poor flatness of the membrane layer, and the membrane pure water flux is 1780LMH at 0.1Mpa pressure. The anti-pollution test is carried out using soybean protein dispersion (0.1MPa, 1wt%), and its 48h operating flux is Stable at 112LMH.

The comparison of the prepared products of each embodiment and comparative example is shown in the following table:

Data from the above table

The filtration membrane layer of the invention has good flatness, no void defects on the membrane surface, high membrane flux, and the flux of the ceramic membrane prepared by conventional ceramic membrane technology is increased by 50-100%, and the anti-pollution ability is strong. In the test, under the transmembrane pressure difference of 0.1MPa, it is 50-80% higher than the conventional ceramic membrane.

In the preparation method of the present invention, activated carbon powder is prepared into a dispersion liquid, and a thick carbon film layer is coated on a ceramic membrane support by a dip coating method. After drying the activated carbon film layer, the dip coating method or dip coating method is used The membrane method forms a transition membrane layer or a filter membrane layer on the activated carbon membrane layer, and the prepared activated carbon membrane layer fills in the large hole defects of the support, and controls the thickness of the activated carbon membrane layer to prevent the transition layer or the filter layer and the substrate from being insufficiently combined. It is firm and uses the porous structure of the activated carbon itself to prevent the activated carbon film layer from being able to form a transition film layer or filter film layer of sufficient thickness due to insufficient porosity after drying.

The above are only the preferred embodiments of the present invention, so the scope of implementation of the present invention cannot be limited accordingly, that is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the description should still be covered by the present invention. In the range.

Industrial Applicability

The invention discloses a high-flux anti-pollution ceramic filter membrane and a preparation method thereof. The pure water flux under 0.1MPa pressure is 2600-3200 LMH, which comprises a ceramic membrane support body and a ceramic membrane support body arranged on the surface of the ceramic membrane support body. The transition membrane layer and the filtration membrane layer have a stable flux of 190-240 LMH of 1 wt % soybean protein dispersion under 0.1 MPa pressure for 48 hours. The filtration membrane layer prepared by the invention has good flatness, no void defect on the membrane surface, high membrane flux and strong anti-pollution ability; the preparation method of the invention can prevent the transition membrane layer from collapsing into the inside of the support body, thereby improving the flatness of the membrane layer, Reduce membrane resistance, improve membrane flux and anti-fouling performance, with industrial practicability.

Claims

A high-flux anti-pollution ceramic filter membrane is characterized by comprising a ceramic membrane support body, a transition membrane layer and a filter membrane layer sequentially arranged on the surface of the ceramic membrane, and the pore diameter of the ceramic membrane support body is 5-30 μm The porosity of the filtration membrane layer is 36-40%, the surface of the membrane layer is smooth, the filtration precision of the prepared ceramic membrane is 100nm, and the stable flux of 1wt% soybean protein dispersion liquid under 0.1MPa pressure for 48h is 190 -240LMH.
The high-flux anti-pollution ceramic filter membrane according to claim 1, wherein the ceramic membrane support body is alumina, and the pore size is 5-10 μm.
The high-flux anti-pollution ceramic filter membrane according to claim 1, wherein the ceramic membrane support body is silicon carbide, and the pore size is 10-30 μm.
The high-flux anti-pollution ceramic filter membrane according to claim 1, wherein the thickness of the filter membrane layer is 25-35 μm.
A preparation method of a high-flux anti-pollution ceramic filter membrane is characterized in that: comprising the following steps:

(1) Coating activated carbon powder dispersion liquid on the ceramic membrane support, the concentration of the activated carbon powder dispersion liquid is 1-3wt%, and the particle size of the activated carbon powder in the activated carbon powder dispersion liquid is 0.5-1 μm; Drying to form an activated carbon film with a thickness of 3-6 μm;

(2) Coat the transition film layer coating liquid on the activated carbon film layer by the dip coating method, carry out drying and sintering, the sintering temperature is 1500-1650 ℃, the time is 2-6h, and the transition film layer is formed;

(3) Coat the filter membrane layer coating liquid on the transition membrane layer by the dip coating method, and then dry and sinter. Ceramic filter membrane layer.
The preparation method according to claim 5, wherein the ceramic membrane support is an alumina ceramic membrane with a pore diameter of 5-10, the transition membrane is alumina with a thickness of 60 μm, and D50=3um.
The preparation method according to claim 6, wherein the filter layer is an alumina filter membrane layer with a thickness of 30 μm and a porosity of 38%.
The preparation method according to claim 5, wherein the ceramic membrane support is a silicon carbide ceramic membrane with a pore diameter of 10-30, and the transition film thickness is 30-80 μm of silicon carbide D50=3.5-4.2 um.
The preparation method according to claim 5, wherein the filter layer is an alumina filter membrane layer with a thickness of 25-35 μm and a porosity of 36-40%.