CN111744370A - Hollow fiber composite membrane, preparation method and application thereof - Google Patents
Hollow fiber composite membrane, preparation method and application thereof Download PDFInfo
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Abstract
The invention belongs to the field of sewage treatment, and particularly relates to a hollow fiber composite membrane, and a preparation method and application thereof. The invention relates to a hollow fiber composite membrane. The hollow fiber composite membrane comprises a supporting layer, an intermediate layer and a surface layer which are sequentially arranged from inside to outside; the supporting layer plays a role of mechanical support, the middle layer plays a role of intermediate transition, and the epidermal layer is a compact functional cortex and plays a role of oxygen transmission and a biomembrane carrier; the penetration thickness of the skin layer embedded in the intermediate layer accounts for 0.01-0.5 of the thickness of the skin layer. The invention has good mechanical strength, oxygen transmission performance and biological affinity, and is very suitable for the MABR process of bubble-free aeration oxygen supply.
Description
Technical Field
The invention belongs to the field of sewage treatment, and particularly relates to a hollow fiber composite membrane, and a preparation method and application thereof.
Background
A Membrane Aeration bioreactor (MABR for short) is a novel high-efficiency sewage treatment process formed by organically coupling the process of a traditional biomembrane Reactor with a gas Membrane separation technology. The MABR technology has the advantages of high oxygen transmission efficiency, low process energy consumption, good operation flexibility, easy modularization integration and the like, and is concerned more and more in the fields of sewage treatment, water body restoration and the like.
The MABR process is different from the traditional bubbling aeration mode, bubble-free aeration is carried out by utilizing a gas membrane, and oxygen is directly utilized by microorganisms covered on the surface of the membrane after passing through the membrane. Under the condition of keeping the gas pressure lower than the membrane bubble point pressure, air or pure oxygen can enter the water body in a molecular form, so that the utilization efficiency of the oxygen by the microorganisms is higher than that of the traditional aeration process.
The gas film mainly plays two roles in the MABR process, namely providing a carrier for the growth of microorganisms and providing an oxygen source for the microorganisms attached to the surface of the film, so that the MABR film has the following basic properties: low mass transfer resistance and high oxygen permeability, moderate bubble point pressure, good mechanical properties and bioaffinity (CN 203139913U, a composite membrane for MABR).
Currently, there are two main types of membranes actually used in the MABR process:
(1) hydrophobic microporous membranes, typically PTFE hollow fiber membranes and polypropylene (PP) hollow fiber membranes. Due to hydrophobicity, the membrane pores are not wetted by water, namely water cannot spontaneously enter the membrane pores of the hydrophobic microporous membrane, but oxygen in the gas phase main body can directly diffuse into the biofilm to be utilized by microorganisms. The hydrophobic microporous membrane has the advantages of low mass transfer resistance, high oxygen transmission efficiency and the like, but has the defects of low aeration pressure, and micropores can be attached and blocked by secretion of microorganisms along with the increase of the service time, so that membrane pores are wetted and polluted, the gas mass transfer resistance is increased greatly, and the efficient implementation of an MABR (moving activated biofilm reactor) process is influenced;
(2) homogeneous dense membranes, which are generally made of a material with selective permeability, such as Polydimethylsiloxane (PDMS). Because the compact membrane structure has no micropores, the problems of pollution and blockage do not exist, but the critical weakness is that the transfer of oxygen is completely controlled by the dissolution diffusion coefficient of the membrane material, and the mass transfer efficiency of the oxygen is low. In addition, the PDMS material has the defects of high cost, poor mechanical strength, easy occurrence of wire breakage in the use process and the like, and the large-scale practical application of the PDMS material is limited;
in view of the above problems, attempts have been made to develop a composite membrane by coupling the structures of the above two membranes, i.e., a selectively permeable membrane having high permeability composed of a selectively permeable skin layer and a porous support layer (CN 203139913U, a composite membrane for MABR; CN 103182254B, a composite membrane for MABR and a method for producing the same). In theory, the composite membrane is the most suitable membrane for the MABR process. The material of the selective permeable skin layer can be PDMS, and the material has good air permeability and certain oxygen-nitrogen separation performance; the porous supporting layer is optimally selected to be PTFE, and has good hydrophobicity, high mechanical strength and low ventilation pressure, thereby being beneficial to reducing the operation energy consumption. However, because the surface pore diameter of the PTFE microporous membrane is generally large (>0.1 μm), when the PDMS layer is prepared by solution coating, heating and crosslinking methods, the coating PDMS solution is very easy to leak into the membrane pores due to the overlarge membrane pores of the base membrane, so that the crosslinked product cannot be bridged and collapsed, and the prepared PDMS layer has a large number of defects and cannot form a compact structure. In addition, the PDMS layer is very easy to break and fall off in the using process, and the hollow fiber composite membrane with good practicability and stability is difficult to prepare.
Disclosure of Invention
1. Problems to be solved
Aiming at the problem of poor strength of the surface layer of the composite membrane in the prior art, the invention provides the hollow fiber composite membrane, the permeation layer embedded in the middle layer of the surface layer accounts for 0.01-0.5 of the thickness of the surface layer, and the permeation layer improves the bonding strength between the two layers, so that the surface layer is not easy to crack and fall off, and the problem of poor strength of the surface layer is solved.
Furthermore, the invention also provides application of the hollow fiber composite membrane in an MABR (moving active radical biofilm reactor) process, and the composite membrane with better mechanical strength and stability is used, so that the service life of the device is prolonged.
The invention further provides a preparation method of the hollow fiber composite membrane, which comprises the steps of preparing the supporting layer, the middle layer and the surface layer in sequence, controlling the thickness of the permeating layer embedded into the middle layer of the surface layer to be 0.01-0.5 of that of the surface layer, and being simple in process, easy to prepare the hollow fiber composite membrane with good practicability and stability and high yield.
2. Technical scheme
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the invention provides a hollow fiber composite membrane, which comprises a hollow fiber composite membrane and a hollow fiber composite membrane, wherein the hollow fiber composite membrane is sequentially arranged from inside to outsideA support layer, an intermediate layer, and a skin layer; the average pore diameter of the side of the middle layer far away from the supporting layer is P1The average pore diameter of the side of the intermediate layer in contact with the support layer is P2，P1＜P2(ii) a The penetration thickness of the skin layer embedded in the middle layer is H1Thickness of the skin layer of H2，H1:H2＝0.05-0.5。
Preferably, the support layer has a pore size of 1-5 μm, a porosity of 60% -85%, and/or the intermediate layer has an average pore size P on the side facing away from the support layer1And P is1＝10-50nm。
Preferably, the penetration thickness of the intermediate layer embedded in the support layer is H3The thickness of the intermediate layer is H4，H3:H4＝0.1-0.5。
Preferably, the thickness of the intermediate layer is H4，H420-100 μm, thickness of epidermal layer H2，H2＝0.5-10μm。
Preferably, the support layer and the intermediate layer are made of fluorine-containing compounds.
Preferably, the skin layer is made of polydimethylsiloxane.
Preferably, the support layer is made of polytetrafluoroethylene; the middle layer is made of a hydrophobic material, and the hydrophobic material is polyvinylidene fluoride.
The invention also provides an application of the hollow fiber composite membrane for the MABR in an MABR process.
The invention also provides a preparation method of the hollow fiber composite membrane, which comprises the following steps,
s100, preparation of a supporting layer: mixing the raw materials and the solvent, curing, and sequentially carrying out paste extrusion, stretching and sintering processes on the cured mixture to obtain a supporting layer; the average pore diameter of the supporting layer is 1-5 μm, and the porosity is 60% -85%;
s200, preparing a supporting layer/middle layer composite membrane, namely coating the supporting layer with a solution, performing phase inversion solidification and forming to prepare the supporting layer/middle layer composite membrane; the average pore diameter of the side of the middle layer of the support layer/middle layer composite membrane far away from the support layer is P1The average pore diameter of the side of the intermediate layer in contact with the support layer is P2，P1＜P2And P is1＝10-50nm；
S300, preparing a supporting layer/middle layer/epidermal layer composite membrane, coating a coating liquid on the supporting layer/middle layer composite membrane, and heating to obtain the supporting layer/middle layer/epidermal layer composite membrane; the penetration thickness of the skin layer of the support layer/intermediate layer/skin layer composite film embedded into the intermediate layer is H1Thickness of the skin layer of H2，H1:H2＝0.05-0.5。
Preferably, the solution coating of S200 further comprises applying pressure at a pressure value of 0.05-0.5 atm.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) according to the hollow fiber composite membrane, the supporting layer plays a role in mechanical supporting, the middle layer plays a role in intermediate transition, and the epidermal layer is a compact functional cortex and plays a role in oxygen transmission and a biological membrane carrier; the intermediate level firmly combines supporting layer and epidermal layer, and the epidermal layer has certain infiltration thickness, has improved the joint strength between two-layer, avoids can appearing peeling off, the action of droing in the in-service use process, has strengthened complex film performance, increase of service life has solved the poor problem of intensity of the epidermal layer of the complex film among the prior art.
(2) According to the hollow fiber composite membrane, the pore diameter of the supporting layer limits the macroporous structure of the supporting layer, and the porous characteristic of the supporting layer is favorable for reducing gas transfer resistance; when the aperture is 1-5 μm, the intermediate layer has a certain penetration thickness relative to the support layer, so that the mechanical strength of the composite membrane is enhanced, and the intermediate layer is prevented from falling off; and the thickness of the skin layer determines the oxygen transmission permeation flux of the composite membrane.
(3) According to the hollow fiber composite membrane, the supporting layer and the middle layer are made of hydrophobic materials, so that membrane pores can be prevented from being wetted due to water vapor condensation in the using process, and the increase of oxygen mass transfer resistance can be avoided; the middle layer and the supporting layer are both fluorine-containing compounds, so that the compatibility is good, and the problem of peeling between the two layers is solved; moreover, when the skin layer is polydimethylsiloxane and the middle layer is polyvinylidene fluoride, the middle layer and the skin layer also have good binding capacity and are prevented from peeling off.
(4) The application of the hollow fiber composite membrane in the MABR technology uses the composite membrane with better mechanical strength and stability, and prolongs the service life of the device.
(5) The preparation method of the hollow fiber composite membrane is simple in preparation process, the composite membrane is prepared by applying pressures of different degrees, and the yield is high.
Drawings
FIG. 1 is a schematic structural view of the present invention;
fig. 2 is a schematic cross-sectional view of the present invention.
Wherein: 100. a support layer; 200. an intermediate layer; 210. a permeable zone II; 300. a skin layer; 400. a cavity.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The invention is described in detail below with reference to specific exemplary embodiments. It will, however, be understood that various modifications and changes may be made without departing from the scope of the invention as defined in the appended claims. The detailed description and drawings are to be regarded as illustrative rather than restrictive, and any such modifications and variations are intended to be included within the scope of the present invention as described herein. Furthermore, the background is intended to be illustrative of the state of the art as developed and the meaning of the present technology and is not intended to limit the scope of the invention or the application and field of application of the invention.
Example 1
The invention provides a hollow fiber composite membrane which can be used for an MABR (moving average membrane bioreactor) process. As shown in fig. 1, the hollow fiber composite membrane includes a support layer 300, an intermediate layer 200, and a skin layer 100, wherein the intermediate layer 200 is disposed between the support layer 300 and the skin layer 100, and is used to solve the problem that the skin layer 100 is likely to peel off when directly covering the support layer 300. As shown in fig. 2, the hollow fiber composite membrane is provided with a cavity 400 through which gas passes, and the support layer 300, the intermediate layer 200, and the skin layer 100 are sequentially disposed from the cavity 400 to the outside.
The supporting layer 300 is a macroporous supporting base film layer, plays a role of mechanical support, avoids the phenomenon of yarn breakage in the use process, and has the tensile strength of more than 20 MPa. When the pore diameter is 1-5 μm and the porosity is 60% -85%, the hydrophobic and porous characteristics are favorable for reducing the gas transfer resistance. The support layer 300 and the intermediate layer 200 are made of a fluorine-containing compound, and further, the support layer 300 is typically Polytetrafluoroethylene (PTFE).
The middle layer 200 is a mesoporous film transition layer, plays a role in middle transition, and firmly bonds the support layer 300 and the skin layer 100, thereby realizing uniform defect-free preparation of the skin layer 100. The intermediate layer 200 is made of a hydrophobic material, and is generally made of polyvinylidene fluoride (PVDF). The hydrophobic nature of the middle layer 200 also avoids wetting by water vapor condensation, thereby increasing oxygen mass transfer resistance and the like. The thickness of the intermediate layer 200 is H4，H420-100 μm, a permeation layer ii 210 is disposed between the intermediate layer 200 and the support layer 300, and the permeation layer ii 210 is a portion of the intermediate layer 200 embedded in the support layer 300. The thickness of the permeation layer defines the form of the connection between the two films and determines the strength of the bond between the two layers. If the permeable layer is not present, the two layers of films can be stripped and fall off in the actual use process, and the service performance and the service life of the composite film are influenced. The thickness of the permeable layer II 210 is H3The thickness of the intermediate layer 200 is H4，H3:H40.1-0.5. Furthermore, the intermediate layer 200 has an asymmetric structure, and the side of the intermediate layer 200 away from the support layer 300 has a mesoporous structure with an average pore diameter P1The side of the intermediate layer 200 contacting the support layer 300 is a finger-like macroporous structure with an average pore diameter P2，P1＜P2And P is110-50 nm. If the mean pore diameter P1Too large a size may not allow uniform preparation of the skin layer material on the intermediate layer 200, if the average pore diameter P1If the size is too small, the gas permeability of the intermediate layer 200 itself is poor, and the oxygen transmission requirement of the MABR membrane cannot be satisfied.
The skin layer 100 is a dense functional layer, typically Polydimethylsiloxane (PDMS), that acts as an oxygen transport and biofilm carrier, and its dense structure prevents wetting and fouling of the MABR membrane. It is noted that when the skin layer 100 is a PDMS layer and the intermediate layer 200 is a PVDF layer, the two layers have excellent bonding ability to prevent the peeling phenomenon. The skin layer 100 has a thickness H2，H20.5-10 μm. The thickness of the skin layer 100 determines the oxygen transmission permeation flux of the composite membrane, i.e., the process efficiency of the MABR process. Be provided with between epidermal layer 100 and the intermediate level 200 and permeate layer I, permeate layer I is the part of epidermal layer 100 embedding intermediate level 200, and the thickness of permeating layer I is H1The thickness of the skin layer 100 is H2，H1:H20.05-0.5. The design can improve the bonding strength between two layers, avoid the stripping and falling actions in the actual use process, enhance the service performance of the composite film and prolong the service life.
The preparation method of the hollow fiber composite membrane of the invention comprises the following steps,
s100, preparation of a support layer 100: mixing the raw materials and the solvent, curing, and sequentially carrying out paste extrusion, stretching and sintering processes on the cured mixture to obtain a supporting layer 100; the average pore diameter of the supporting layer 100 is 1-5 μm, and the porosity is 60% -85%;
s200, preparing a supporting layer/middle layer composite membrane, namely coating the supporting layer 100 with a solution, performing phase inversion solidification and forming to prepare the supporting layer/middle layer composite membrane; the average pore diameter of the support layer/intermediate layer composite film on the side of the intermediate layer 200 remote from the support layer 100 is P1The average pore diameter of the side of the intermediate layer 200 in contact with the support layer 300 is P2，P1＜P2And P is110-50 nm; the solution coating process further comprises applying pressure at a pressure of 0.05 to 0.5 atm;
s300, preparing a supporting layer/middle layer/epidermal layer composite membrane, coating a coating liquid on the supporting layer/middle layer composite membrane, and heating to obtain the supporting layer/middle layer/epidermal layer composite membrane; the thickness of the permeation layer in which the skin layer 100 of the support layer/intermediate layer/skin layer composite film is embedded in the intermediate layer 200 is H1The thickness of the skin layer 100 is H2，H1:H2＝0.05-0.5。
In this example, the specific preparation method is as follows:
1) uniformly mixing PTFE dispersion resin and solvent oil, wherein the mass fractions are 76% and 24% respectively;
2) curing the uniformly mixed materials at 40 ℃ for 12 hours;
3) loading the cured mixture into a prepressing device, prepressing and degassing for 5min under 2.0MPa to obtain a PTFE blank;
4) loading the prepared PTFE blank into paste extrusion equipment, and extruding at 60 ℃ to obtain a primary PTFE hollow fiber membrane;
5) carrying out heat treatment on the nascent PTFE hollow fiber membrane at 200 ℃ for 10min for degreasing to remove solvent oil;
6) stretching the degreased PTFE hollow fiber membrane by 5.0 times in the length direction at 250 ℃ at a stretching speed of 10 m/min;
7) sintering the stretched PTFE hollow fiber membrane at 360 ℃ for 5min to prepare a PTFE support layer, wherein the inner diameter of the PTFE support layer is 0.8mm, the outer diameter of the PTFE support layer is 1.6mm, the average pore diameter of the PTFE support layer is 5.0 mu m, the porosity of the PTFE support layer is 85 percent, and the tensile strength of the PTFE support layer is 32 MPa;
8) dissolving PVDF in N, N-dimethylacetamide, wherein the mass fraction of PVDF is 10%, and mechanically stirring at 80 ℃ for 12 hours to prepare a uniform and transparent casting solution;
9) coating the casting solution on the outer surface of the PTFE support layer by using self-made spinning equipment, applying 0.2atm pressure in the coating process to enable the casting solution to partially permeate into PTFE hollow fiber membrane pores, and then soaking into a hydrogel system for phase conversion, thereby preparing the PTFE/PVDF composite membrane. PVDF Total thickness H450 μm, thickness H of permeation layer II 210 in PTFE-based film320 μm, the PVDF intermediate layer is of asymmetric structure, the side close to the PTFE support layer is of a finger-like macroporous structure, while the side far away from the PTFE support layer has smaller surface pores with an average pore diameter P1Is 10 nm;
10) dissolving vinyl PDMS, a hydrogen-containing silicone oil cross-linking agent and a platinum catalyst in n-hexane, wherein the mass concentrations are respectively 2.0%, 0.5% and 500ppm, and mechanically stirring uniformly to obtain a coating liquid;
11) removing water drops on the surface of the PTFE/PVDF composite membrane by using an air knife, immersing the PTFE/PVDF composite membrane into PDMS coating liquid, and keeping the PTFE/PVDF composite membrane for 1min for 3 times; air (a)Drying for 5min, and performing heat treatment at 75 ℃ for 120min to obtain a PTFE/PVDF/PDMS hollow fiber composite membrane; thickness H of permeation layer I for PDMS permeating PVDF membrane hole10.5 μm; total thickness H of PDMS skin layer2And 5.0 μm.
Example 2
This example was substantially the same as example 1 except that a pressure of 0.05atm was applied during the coating process, and the average pore diameter of the PTFE support layer in the prepared composite membrane was 3.0 μm and the porosity was 70%. PVDF Total thickness H420 μm, thickness H of the permeation layer II 210 in the PTFE-based film3:H40.5, the PVDF intermediate layer is of an asymmetric structure, the side close to the PTFE support layer is of a finger-shaped macroporous structure, and the surface of the side far away from the PTFE support layer is smaller, and the average pore diameter is 30 nm. Total thickness H of PDMS skin layer2Is 10 μm; thickness H of permeable layer I1:H2＝0.05。
Example 3
This example was substantially the same as example 1 except that a pressure of 0.5atm was applied during the coating process, and the average pore diameter of the PTFE support layer in the prepared composite membrane was 1.0 μm and the porosity was 60%. PVDF Total thickness H4Thickness H of permeation layer II 210 in PTFE-based film of 100 μm3:H4The PVDF intermediate layer is of an asymmetric structure, the side close to the PTFE support layer is of a finger-shaped macroporous structure, and the side far away from the PTFE support layer is smaller in surface pores, and the average pore diameter is 50 nm. Total thickness H of PDMS skin layer2Is 2 μm; thickness H of permeable layer I1:H2＝0.5。
Comparative example 1
The basic content of this comparative example is the same as example 1, except that the specific preparation steps are as follows:
1) uniformly mixing PTFE dispersion resin and solvent oil, wherein the mass fractions are 76% and 24% respectively;
2) curing the uniformly mixed materials at 40 ℃ for 12 hours;
3) loading the cured mixture into a prepressing device, prepressing and degassing for 5min under 2.0MPa to obtain a PTFE blank;
4) loading the prepared PTFE blank into paste extrusion equipment, and extruding at 60 ℃ to obtain a primary PTFE hollow fiber membrane;
5) carrying out heat treatment on the nascent PTFE hollow fiber membrane at 200 ℃ for 10min for degreasing to remove solvent oil;
6) stretching the degreased PTFE hollow fiber membrane by 5.0 times in the length direction at 250 ℃ at a stretching speed of 10 m/min;
7) sintering the stretched PTFE hollow fiber membrane at 360 ℃ for 5min to prepare a PTFE hollow fiber support base membrane, wherein the inner diameter of the PTFE hollow fiber support base membrane is 0.8mm, the outer diameter of the PTFE hollow fiber support base membrane is 1.6mm, the average pore diameter of the PTFE hollow fiber support base membrane is 5.0 mu m, the porosity of the PTFE hollow fiber support base membrane is 85 percent, and the tensile strength of the PTFE hollow fiber support base membrane is;
8) dissolving vinyl PDMS, a hydrogen-containing silicone oil cross-linking agent and a platinum catalyst in n-hexane, wherein the mass concentrations are respectively 2.0%, 0.5% and 500ppm, and mechanically stirring uniformly to obtain a coating liquid;
9) removing water drops on the surface of the PTFE membrane by using an air knife, immersing the PTFE membrane in PDMS coating liquid, and keeping the time for 1min for 3 times; after air drying for 5min, heat treating at 75 deg.C for 120min to obtain PTFE/PDMS hollow fiber composite membrane.
Comparative example 2
The basic content of this comparative example is the same as example 1, except that the specific preparation steps are as follows:
1) dissolving PVDF in N, N-dimethylacetamide, wherein the mass fraction of PVDF is 10%, and mechanically stirring at 80 ℃ for 12 hours to prepare a uniform and transparent casting solution;
2) and spinning the membrane casting solution into a hollow fiber membrane by using self-made spinning equipment, and then soaking the hollow fiber membrane into a hydrogel system for phase conversion to obtain the PVDF base membrane. The PVDF basal membrane has the inner diameter of 0.8mm, the outer diameter of 1.2mm, the wall thickness of 200 μm, an asymmetric structure, a finger-shaped macroporous structure on one side of the inner surface, smaller surface pores on one side of the outer surface and an average pore diameter of 10 nm;
3) dissolving vinyl PDMS, a hydrogen-containing silicone oil cross-linking agent and a platinum catalyst in n-hexane, wherein the mass concentrations are respectively 2.0%, 0.5% and 500ppm, and mechanically stirring uniformly to obtain a coating liquid;
4) removing water drops on the surface of the PVDF base film by using an air knife, immersing the PVDF base film into PDMS coating liquid, and keeping the PVDF base film for 1min for 3 times; after air drying for 5min, heat treating at 75 deg.C for 120min to obtain PVDF/PDMS hollow fiber composite membrane. The depth of PDMS permeating into PVDF film hole is 0.5 μm; the total thickness of the PDMS dense film skin layer was 5.0 μm.
In the present comparative example, the PTFE/PDMS, PVDF/PDMS, and PTFE/PVDF/PDMS hollow fiber composite membranes prepared in example 1, comparative example 1, and the present comparative example were subjected to performance characterization, specifically as shown in table 1 below:
TABLE 1 characterization of hollow fiber composite membranes
As can be seen from the table, the hollow fiber composite membrane prepared by the invention has good mechanical strength, oxygen transmission performance and biocompatibility, and is very suitable for the MABR process of bubble-free aeration oxygen supply.
More specifically, although exemplary embodiments of the invention have been described herein, the invention is not limited to these embodiments, but includes any and all embodiments modified, omitted, combined, e.g., between various embodiments, adapted and/or substituted, as would be recognized by those skilled in the art from the foregoing detailed description. The limitations in the claims are to be interpreted broadly based the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. The scope of the invention should, therefore, be determined only by the appended claims and their legal equivalents, rather than by the descriptions and examples given above.
Claims (10)
1. A hollow fiber composite membrane characterized by: comprises a supporting layer (300), an intermediate layer (200) and a skin layer (100) which are arranged from inside to outside in sequence; the intermediate layer (200) has an average pore diameter P on the side facing away from the support layer (300)1The middle layer (200) is connected with the supporting layer (300)The average pore diameter of the contact side is P2，P1＜P2(ii) a Be provided with between epidermal layer (100) and intermediate level (200) and permeate layer I, the thickness of permeating layer I is H1The thickness of the skin layer (100) is H2，H1:H2＝0.05-0.5。
2. A hollow fiber composite membrane according to claim 1, wherein: the support layer (300) has an average pore diameter of 1-5 μm, a porosity of 60% -85%, and/or
The intermediate layer (200) has an average pore diameter P on the side facing away from the support layer (300)1，P1＝10-50nm。
3. A hollow fiber composite membrane according to claim 1, wherein: a permeable layer II (210) is arranged between the middle layer (200) and the supporting layer (300), and the thickness of the permeable layer II (210) is H3The thickness of the intermediate layer (200) is H4，H3:H4＝0.1-0.5。
4. A hollow fiber composite membrane according to claim 1, wherein: the thickness of the intermediate layer (200) is H4，H420-100 μm, the thickness of the skin layer (100) being H2，H2＝0.5-10μm。
5. A hollow fiber composite membrane according to claim 1, wherein: the support layer (300) and the intermediate layer (200) are both made of a fluorine-containing compound.
6. A hollow fiber composite membrane according to claim 1, wherein: the skin layer (100) is made of polydimethylsiloxane.
7. The hollow fiber composite membrane according to claim 5, wherein: the support layer (300) is made of polytetrafluoroethylene; the middle layer (200) is made of a hydrophobic material, and the hydrophobic material is polyvinylidene fluoride.
8. Use of a hollow fibre composite membrane according to any one of claims 1 to 7 in an MABR process.
9. A preparation method of a hollow fiber composite membrane is characterized by comprising the following steps: the specific steps are as follows,
s100, preparation of a support layer (300): mixing the raw materials and the solvent, curing, and sequentially carrying out paste extrusion, stretching and sintering processes on the cured mixture to obtain a supporting layer (300); the average pore diameter of the support layer (300) is 1-5 μm, and the porosity is 60% -85%;
s200, preparing a supporting layer (300)/middle layer (200) composite membrane, namely coating the supporting layer (300) with a solution, performing phase inversion solidification and forming to prepare the supporting layer (300)/middle layer (200) composite membrane; the average pore diameter of the side of the middle layer (200) of the composite film of the support layer (300)/the middle layer (200), which is far away from the support layer (300), is P1The average pore diameter of the side of the intermediate layer (200) in contact with the support layer (300) is P2，P1＜P2And P is1＝10-50nm；
S300, preparing a supporting layer (300)/intermediate layer (200)/skin layer (100) composite film, coating a coating liquid on the supporting layer (300)/intermediate layer (200) composite film, and heating to obtain the supporting layer (300)/intermediate layer (200)/skin layer (100) composite film; the penetration thickness of the skin layer (100) of the support layer (300)/intermediate layer (200)/skin layer (100) composite film embedded into the intermediate layer (200) is H1The thickness of the skin layer (100) is H2，H1:H2＝0.05-0.5。
10. A method for preparing a hollow fiber composite membrane according to claim 9, characterized in that: the solution coating of S200 further comprises applying pressure at a pressure value of 0.05-0.5 atm.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023160073A1 (en) * | 2022-02-23 | 2023-08-31 | 中国石油化工股份有限公司 | Hollow fiber seperation membrane, preparation method therefor and application thereof |
| CN116712868A (en) * | 2023-06-30 | 2023-09-08 | 杭州科百特过滤器材有限公司 | Cellulose virus-removing film with high mechanical strength and preparation process thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023160073A1 (en) * | 2022-02-23 | 2023-08-31 | 中国石油化工股份有限公司 | Hollow fiber seperation membrane, preparation method therefor and application thereof |
| CN116712868A (en) * | 2023-06-30 | 2023-09-08 | 杭州科百特过滤器材有限公司 | Cellulose virus-removing film with high mechanical strength and preparation process thereof |
| CN116712868B (en) * | 2023-06-30 | 2023-10-31 | 杭州科百特过滤器材有限公司 | Cellulose virus-removing film with high mechanical strength and preparation process thereof |
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