CN111760470A - Membrane transfer coating MBR (membrane bioreactor) membrane and preparation method thereof - Google Patents
Membrane transfer coating MBR (membrane bioreactor) membrane and preparation method thereof Download PDFInfo
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- CN111760470A CN111760470A CN202010638785.0A CN202010638785A CN111760470A CN 111760470 A CN111760470 A CN 111760470A CN 202010638785 A CN202010638785 A CN 202010638785A CN 111760470 A CN111760470 A CN 111760470A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
- B01D71/34—Polyvinylidene fluoride
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0011—Casting solutions therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/1236—Particular type of activated sludge installations
- C02F3/1268—Membrane bioreactor systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
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Abstract
The invention discloses a membrane transfer coating MBR membrane and a preparation method thereof. Respectively and synchronously coating the casting solution on the two transfer films; spraying an acrylate adhesion promoter on the surface of the casting solution; simultaneously transferring the two MBR wet membrane layers loaded on the transfer membrane to the upper surface and the lower surface of the support material, and performing vertical rolling compounding to obtain a compounded MBR wet membrane; feeding the two MBR wet membranes loaded on the transfer membrane into a coagulating bath for coagulation, and automatically stripping the transfer membrane and an MBR coagulated membrane layer after coagulation is finished; and (4) enabling the stripped MBR membrane to enter a washing bath, and washing and drying to obtain the MBR membrane. The invention adopts a film transfer coating mode, realizes accurate and controllable thickness, avoids film liquid from permeating into the supporting material, and realizes the consistent structure and performance of two wet film layers; the binding force of the membrane layer and the supporting material is improved, the life cycle of the MBR membrane is prolonged, and the backwashing with higher pressure is realized; the preparation process is simple to operate, and integrated production can be realized.
Description
Technical Field
The invention relates to a preparation method of a membrane transfer coating MBR membrane, and relates to the technical field of water treatment.
Background
MBR, also called Membrane bioreactor (Membrane Bio-Reactor), is a new water treatment technology combining activated sludge process and Membrane separation technology. Compared with the traditional activated sludge method and the multilayer laminar flow and aeration technology, the MBR technology has the advantages of good effluent quality, relatively low sludge yield, small occupied area and the like, so that the introduction of the MBR technology to treat town sewage is a great trend.
MBR membranes used for sewage treatment in MBR technology are mainly divided into four types at present: hollow fiber membranes, flat sheet membranes, ceramic membranes, tubular membranes. The MBR flat membrane has the advantages of simple structure, stable process, strong pollution resistance and long service life, can construct large-scale engineering and the like, and is the first choice for future low-cost and large-scale MBR sewage treatment engineering.
The MBR flat membrane module adopted in the current market is formed by adhering an MBR membrane on an ABS support flat plate, which greatly damages the integrity of the module and seriously influences the packing density and the effective area of the membrane. The adhesion of the film to the module support tends to result in delamination, peeling of the film. The membrane cannot be backwashed due to poor adhesion of the membrane to its support.
Patent CN102510771A discloses a filtration composite, a method for manufacturing the same, and a flat filter element made of the filtration composite, in which a drainage fabric and a 2-layer filtration membrane are laminated to each other via a 2-layer adhesive web to obtain an MBR membrane. According to the method, the mechanical strength between the MBR membrane layer and the drainage fabric is improved by adopting the bonding net, but the problems of insufficient bonding between multiple interfaces, stress concentration of local defects and the like can be caused by the existence of the bonding net, so that the bonding strength between the fabric and the membrane layer is low, and the anti-backwashing capability is low.
Patent CN101035608A discloses an integrated permeation channel membrane, which uses a 3D spacer fabric to connect the surface layers by weaving, form channels in the middle, and further coat the surface of the fabric perpendicularly. The depth of the membrane casting solution penetrating into the interval braided fabric cannot be controlled, so that the MBR membrane layer has the quality problems of non-uniform thickness, non-uniform mechanical strength, non-uniform filtration property and the like, the service life of the MBR membrane component is seriously damaged, and the operation stability of the membrane component is influenced.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the problem that the mechanical property of the conventional MBR membrane module is poor.
In order to solve the technical problem, the invention provides a preparation method of a membrane transfer coating MBR membrane, which is characterized by comprising the following steps:
step 1): uniformly mixing PVDF powder with an organic solvent, a pore-forming agent and a hydrophilic solvent, uniformly stirring for 4-8 hours at a constant speed under the water bath condition of 60-90 ℃ until the PVDF powder is completely dissolved and dispersed, and then filtering by using a filter screen and defoaming to obtain a casting solution;
step 2): respectively and synchronously coating the prepared casting film liquid on the two transfer films;
step 3): spraying an acrylate adhesion promoter on the surface of the casting solution;
step 4): simultaneously transferring the two MBR wet membrane layers loaded on the transfer membrane to the upper surface and the lower surface of the support material, and performing vertical rolling compounding to obtain a compounded MBR wet membrane;
step 5): feeding the two MBR wet membranes loaded on the transfer membrane into a coagulating bath for coagulation, and automatically stripping the transfer membrane and an MBR coagulated membrane layer after coagulation is finished; and (4) enabling the stripped MBR membrane to enter a washing bath, and washing and drying to obtain a finished product MBR membrane.
Preferably, the coating device in step 2) is a slot extrusion coating device or a comma knife extrusion coating device.
Preferably, the transfer film in the step 2) is a steel belt, a PET film, an organic-inorganic composite film or an organic-metal composite film.
More preferably, the transfer film is made of a stainless steel band with the thickness of 0.1-0.5 mm.
Preferably, the mass concentration of the acrylate adhesion promoter in the step 3) is 0.1-1%.
Preferably, the support material in the step 4) is a spacer knitted fabric, a composite fabric or a composite non-woven fabric, and is preferably a spacer knitted fabric.
Preferably, the pressure of the vertical rolling in the step 4) is not more than 2 bar.
Preferably, the coagulating bath in the step 5) is an isopropanol water solution with the mass concentration of 5-50%, the coagulating time is not more than 3 minutes, and the coagulating temperature is 20-70 ℃; the washing bath is water, alcohols, amide solvents or a compound of a plurality of solvents, the washing time is 24-72 hours, the washing temperature is 30-70 ℃, the washing bath is preferably water, and the washing time is 24-48 hours.
Preferably, the transfer film peeled off in the step 5) is washed and dried, and then is recycled.
The invention also provides the MBR membrane prepared by the preparation method of the membrane transfer coating MBR membrane, which is characterized in that a water collecting layer with supporting materials is arranged, and membrane layers are respectively arranged on two sides of the water collecting layer.
The MBR membrane prepared by the invention has controllable structure and thickness, simple preparation method and high production efficiency, and is suitable for industrial scale production.
The invention adopts a membrane transfer coating mode to prepare a flat membrane product with high quality, low cost, long service life and backwashing resistance. Compared with the prior art, the invention has the beneficial effects that:
1. according to the invention, the membrane transfer coating mode is adopted, the membrane casting solution is horizontally coated on the transfer membrane, and the prepared MBR membrane layer has uniform thickness, stable size, small quality fluctuation and simple operation.
2. According to the invention, the wet film is transferred to the surface of the support material and is vertically rolled and compounded, so that the wet film is prevented from permeating into the support material, and the defects of water channel blockage and unstable MBR film thickness caused by excessive permeation of the casting film liquid into the support material are avoided. The vertical compounding can avoid the difference of wet film structure caused by the influence of gravity on the wet film during horizontal compounding.
3. According to the invention, the MBR membrane layer adopts acrylic esters as a hydrophilic solvent and adopts acrylic esters as an adhesion promoter, so that the binding force between the membrane layer and the supporting material is improved, the service life of the MBR membrane can be prolonged, and higher-pressure backwashing can be realized.
4. According to the invention, a membrane transfer coating mode is adopted, the wet membrane is prepared firstly, then the two wet membrane layers are transferred to the upper surface and the lower surface of the supporting material simultaneously, and the MBR membrane is obtained by rolling, compounding, solidifying, washing and drying, so that the integrated production is realized, the instability of twice compounding of the wet membrane is avoided, and the production efficiency is improved.
Drawings
FIG. 1 is a schematic diagram of a membrane transfer coating MBR membrane manufacturing apparatus employed in the present invention;
fig. 2 is a schematic structural diagram of the membrane transfer coating MBR membrane prepared by the present invention.
Detailed Description
In order to make the invention more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.
The reagents and raw materials used in the invention are commercially available, and part of the raw materials may need to be obtained by a powder preparation process, which is a conventional treatment process in the powder industry. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
The structure schematic diagram of the manufacturing equipment for membrane transfer coating of the MBR membrane adopted by the invention is shown in figure 1, and the manufacturing equipment sequentially comprises a support material unwinding roller 1, a pair of composite steering rollers 5, a pair of composite rollers 6, two small guide rollers 8 arranged in a curing pool 7 (for placing a coagulating bath), two large guide rollers 9, two small guide rollers 8 arranged in a washing pool 11 (for placing a washing bath) and an MBR membrane product winding roller 12, wherein both sides of the composite steering rollers 5 are respectively provided with a transfer membrane unwinding roller 2, a membrane liquid casting coating system 3 and a spraying system 4 are sequentially arranged above the space between the transfer membrane unwinding roller 2 and the corresponding composite steering roller 5, and both sides of the first large guide roller 9 are respectively provided with a transfer membrane winding roller 10 (arrows in the figure indicate the membrane running and production directions).
The obtained MBR membrane includes a support material 21 with a water collection layer 20, and membrane layers 22 are respectively disposed on both sides of the support material 21, as shown in fig. 2.
Example 1
A preparation method of a membrane transfer coating MBR membrane comprises the following steps:
step 1: preparing a casting solution: uniformly mixing 20 parts of PVDF powder, 5 parts of polyethylene glycol 1000, 3 parts of acrylic ester and 72 parts of dimethylacetamide, uniformly stirring for 6 hours at 80 ℃ in a water bath, filtering by a 150-mesh screen, and carrying out vacuum defoaming treatment to obtain a refined casting solution;
step 2: MBR membrane coating: respectively and synchronously coating the prepared casting film liquid on two 304 stainless steel band transfer films with the thickness of 200 mu m at the coating speed of 0.2m/s in a mode of coating the horizontal upper surfaces of a comma knife coater, wherein the coating speed difference at two sides is not more than +/-2 percent, and the coating thickness is 200 mu m;
and step 3: spraying an adhesion promoter: and spraying the acrylate adhesion promoter with the concentration of 0.5% on the surface of the casting solution.
And 4, step 4: membrane transfer and compounding: transferring two MBR wet films loaded on the transfer film to the upper surface and the lower surface of the spaced knitted fabric at the same time, sending the knitted fabric into a composite rolling working section, and performing vertical composite and rolling to obtain a composite MBR wet film, wherein the rolling pressure is 0.6bar, and the instantaneous pressure deviation is not more than +/-5%;
and 5: and (3) solidification and washing: and (3) conveying the wet MBR membrane into a pure water coagulation tank at 30 ℃ for coagulation for 5 minutes, after the coagulation is finished, running the wet MBR membrane to a stripping roller, simultaneously stripping the transfer membrane from 2 MBR coagulation membranes, and washing and rolling the transfer membrane for later use. And washing the stripped MBR membrane in pure water at 30 ℃, washing for 36 hours, and drying to obtain a finished product MBR membrane.
Example 2
A preparation method of a membrane transfer coating MBR membrane comprises the following steps:
step 1: preparing a casting solution: uniformly mixing 20 parts of PVDF powder, 5 parts of polyethylene glycol 1000, 3 parts of acrylic ester and 72 parts of dimethylacetamide, uniformly stirring for 6 hours at 80 ℃ in a water bath, filtering by a 150-mesh screen, and carrying out vacuum defoaming treatment to obtain a refined casting solution;
step 2: MBR membrane coating: respectively and synchronously coating the prepared casting film liquid on two 304 stainless steel band transfer films with the thickness of 200 mu m at the coating speed of 0.2m/s in a mode of coating the horizontal upper surfaces of a comma knife coater, wherein the coating speed difference at two sides is not more than +/-2 percent, and the coating thickness is 200 mu m;
and step 3: spraying an adhesion promoter: and spraying the acrylate adhesion promoter with the concentration of 0.3% on the surface of the casting solution.
And 4, step 4: membrane transfer and compounding: transferring two MBR wet films loaded on the transfer film to the upper surface and the lower surface of the spaced knitted fabric at the same time, sending the knitted fabric into a composite rolling working section, and performing vertical composite and rolling to obtain a composite MBR wet film, wherein the rolling pressure is 0.3bar, and the instantaneous pressure deviation is not more than +/-5%;
and 5: and (3) solidification and washing: and (3) conveying the wet MBR membrane into a pure water coagulation tank at 30 ℃ for coagulation for 5 minutes, after the coagulation is finished, running the wet MBR membrane to a stripping roller, simultaneously stripping the transfer membrane from 2 MBR coagulation membranes, and washing and rolling the transfer membrane for later use. And washing the stripped MBR membrane in pure water at 30 ℃, washing for 36 hours, and drying to obtain a finished product MBR membrane.
And (3) performance testing:
1) the distance of the membrane casting solution penetrating into the knitted fabric is as follows: and the distance from the casting solution to the interior of the knitted fabric is measured by adopting a SEM observation method for enhancing the section of the thin MBR flat membrane with the three-dimensional spaced knitted fabric as the base material, and a section sample of the thin MBR flat membrane with the three-dimensional spaced knitted fabric as the base material is prepared by adopting a particle beam cutting method.
2) And (3) testing the water flux: testing the water flux of the prepared MBR membrane by using an ultrafiltration cup, wherein the pressure is-0.1 Mpa;
3) and (3) testing the backwashing strength: the online water pump pressure flushing method is adopted for testing, and the backwashing strength test is the lowest pressure when the structure or the function is damaged during the backwashing of the MBR membrane.
TABLE 1
Claims (6)
1. A preparation method of a membrane transfer coating MBR membrane is characterized by comprising the following steps:
step 1): uniformly mixing PVDF powder with an organic solvent, a pore-forming agent and a hydrophilic solvent, uniformly stirring for 4-8 hours at a constant speed under the water bath condition of 60-90 ℃ until the PVDF powder is completely dissolved and dispersed, and then filtering by using a filter screen and defoaming to obtain a casting solution;
step 2): respectively and synchronously coating the prepared casting film liquid on the two transfer films;
step 3): spraying an acrylate adhesion promoter on the surface of the casting solution;
step 4): simultaneously transferring the two MBR wet membrane layers loaded on the transfer membrane to the upper surface and the lower surface of the support material, and performing vertical rolling compounding to obtain a compounded MBR wet membrane;
step 5): feeding the two MBR wet membranes loaded on the transfer membrane into a coagulating bath for coagulation, and automatically stripping the transfer membrane and an MBR coagulated membrane layer after coagulation is finished; and (4) enabling the stripped MBR membrane to enter a washing bath, and washing and drying to obtain a finished product MBR membrane.
2. The method for preparing the MBR membrane for membrane transfer coating according to claim 1, wherein the coating equipment adopted in the step 2) is a slot extrusion coating equipment or a comma knife extrusion coating equipment.
3. The method for preparing the membrane transfer coating MBR membrane according to claim 1, wherein the transfer membrane in the step 2) is a steel belt, a PET membrane, an organic-inorganic composite membrane or an organic-metal composite membrane.
4. The preparation method of the membrane transfer coating MBR membrane, which is characterized in that the transfer membrane adopts a stainless steel band with the thickness of 0.1-0.5 mm.
5. The method for preparing the MBR membrane for membrane transfer coating according to claim 1, wherein the support material in the step 4) is a spacer knitted fabric, a composite fabric or a composite non-woven fabric.
6. The MBR membrane prepared by the preparation method of the membrane transfer coating MBR membrane according to any one of claims 1-5, is characterized in that a support material (21) with a water collecting layer (20) is provided, and membrane layers (22) are respectively arranged on two sides of the support material (21).
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| CN202010638785.0A CN111760470A (en) | 2020-07-06 | 2020-07-06 | Membrane transfer coating MBR (membrane bioreactor) membrane and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112320930A (en) * | 2020-10-16 | 2021-02-05 | 中国海诚工程科技股份有限公司 | MBR flat membrane for enhancing three-dimensional space knitted fabric substrate and preparation method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101035608A (en) * | 2004-08-11 | 2007-09-12 | 佛兰芒技术研究所 | Integrated permeate channel membrane |
| CN101685256A (en) * | 2008-09-25 | 2010-03-31 | 富士胶片株式会社 | Photosensitive film manufacturing method, photosensitive film, photosensitive laminating body, permanent pattern forming method and printing circuit board |
| CN102582200A (en) * | 2011-11-27 | 2012-07-18 | 中国海诚工程科技股份有限公司 | Device and method for transfer coating of pre-drying thin film of lithium battery diaphragm |
| WO2015133364A1 (en) * | 2014-03-03 | 2015-09-11 | Jnc株式会社 | Composite fine porous membrane and filter using same |
-
2020
- 2020-07-06 CN CN202010638785.0A patent/CN111760470A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101035608A (en) * | 2004-08-11 | 2007-09-12 | 佛兰芒技术研究所 | Integrated permeate channel membrane |
| CN101685256A (en) * | 2008-09-25 | 2010-03-31 | 富士胶片株式会社 | Photosensitive film manufacturing method, photosensitive film, photosensitive laminating body, permanent pattern forming method and printing circuit board |
| CN102582200A (en) * | 2011-11-27 | 2012-07-18 | 中国海诚工程科技股份有限公司 | Device and method for transfer coating of pre-drying thin film of lithium battery diaphragm |
| WO2015133364A1 (en) * | 2014-03-03 | 2015-09-11 | Jnc株式会社 | Composite fine porous membrane and filter using same |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112320930A (en) * | 2020-10-16 | 2021-02-05 | 中国海诚工程科技股份有限公司 | MBR flat membrane for enhancing three-dimensional space knitted fabric substrate and preparation method thereof |
| CN112320930B (en) * | 2020-10-16 | 2022-09-23 | 中国海诚工程科技股份有限公司 | MBR flat membrane for enhancing three-dimensional interval knitted fabric substrate and preparation method thereof |
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Application publication date: 20201013 |