A method for preparing a super-hydrophilic hollow fiber ultrafiltration membrane filament and an article

Abstract

The application provides a preparation method of super-hydrophilic hollow fiber ultrafiltration membrane filaments, comprising the following steps: S1, uniformly mixing raw materials to obtain a casting solution; S2, uniformly mixing raw materials to obtain a hollow medium; S3, injecting the casting solution of S1 and the hollow medium of S2 into a spinning device for extrusion, forming a membrane in a coagulation bath through a non-solvent induced phase separation method, and then performing water bath heat treatment after a rinsing water bath replacement, thereby obtaining the product; and the application further discloses the product. The method has a short technological process, few control points, stable membrane forming performance, and is easy to mass produce. The propylene glycol block polyether, end-vinyl polysiloxane, silicon dioxide and chloroplatinic acid are crosslinked and grafted with polyvinylidene fluoride to form a net support structure layer in which hydrophilic and hydrophobic materials are connected with each other, the hydrophilic material is permanently fixed in the membrane filaments, the water flux, mechanical strength and pollution resistance of the membrane filaments are improved, the filtration precision is improved, the service life of the ultrafiltration membrane is prolonged, and the maintenance, cleaning and operation costs during the use of the ultrafiltration are reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of water treatment filter membranes, in particular to a preparation method of super-hydrophilic hollow fiber ultrafiltration membrane filaments and a product. BACKGROUND

[0002] The energy-saving and environment-friendly industry is a strategic emerging industry cultivated by the country, and is an important support for filling the resource and environment gap and improving the quality of the ecological environment. In the field of water resources, membrane water treatment has the advantages of high treatment efficiency, short process flow, easy control, flexible use, small land occupation of membrane separation devices, and full automation of production, and plays an important role in the energy-saving and environment-friendly links in the fields of energy and power, non-ferrous metallurgy, seawater desalination, water supply treatment, sewage reuse, and medicine and food.

[0003] The ultrafiltration membrane is a membrane structure of membrane water treatment, and is generally produced by hot-induced phase separation (TIPS, referred to as a hot method) and non-solvent-induced phase separation (NIPS, referred to as a wet method) spinning. In the prior art, the hot method spinning adopts an extrusion molding process, has a short operation flow, and has less waste liquid, but the membrane filament separation effect, hydrophilicity, and anti-pollution ability are poor, the service life is short, and the cost is high; the wet method spinning is a widely used membrane preparation process in the current ultrafiltration membrane industry, the membrane filament separation pore size is small, and the anti-pollution performance is good, but the longitudinal tensile strength and hydrophilicity are insufficient, the service life is 2-5 years, the cleaning frequency is high, and therefore the energy consumption is high, resulting in high use cost of the ultrafiltration membrane. The general preparation method of the ultrafiltration membrane is blending of hydrophobic materials and hydrophilic materials, because the hydrophobic materials and the hydrophilic materials have repulsion, the two kinds of materials cannot be linked together in the microstructure, and the hydrophilic material is easy to dissolve in water, so the ordinary ultrafiltration membrane has good hydrophilicity and large flux at the beginning of use, but the hydrophilic material is lost slowly with time, the performance of the ultrafiltration membrane is poor, and the ultrafiltration membrane is scrapped. SUMMARY

[0004] In order to solve the problems of the prior art, the application provides a preparation method of super-hydrophilic hollow fiber ultrafiltration membrane filaments and a product, the problems that the hydrophilic material of the current ultrafiltration membrane is easy to lose are solved through optimization of the formula and process, the membrane filaments have permanent hydrophilic performance, and the water permeation amount, pollution resistance, mechanical strength, and service life of the prepared ultrafiltration membrane are improved.

[0005] To achieve the above purposes, the technical scheme adopted by the application is as follows:

[0006] A preparation method of super-hydrophilic hollow fiber ultrafiltration membrane filaments comprises the following steps:

[0007] S1, N,N-dimethylacetamide, polyvinylidene fluoride, polyvinylpyrrolidone, glycerol, propylene glycol block polyether, end-vinyl polysiloxane, silicon dioxide and chloroplatinic acid are sequentially added into a stirred tank, stirred uniformly under oil bath, and a casting solution is obtained; polyvinylidene fluoride is a hydrophobic material (main material), polyvinylpyrrolidone is a hydrophilic material (secondary main material), glycerol is a pore forming agent, polyether (random series) is a hydrophilic auxiliary material, silicon dioxide is a hydrophilic auxiliary material, end-vinyl polysiloxane is a crosslinking agent, and chloroplatinic acid is an initiation catalyst; the casting solution of the crosslinking copolymerization of the hydrophilic material and the hydrophobic material is formed in the N,N-dimethylacetamide solution by heating and stirring.

[0008] S2, N,N-dimethylacetamide, glycerol, propylene glycol block polyether and pure water are added to a container, heated and stirred uniformly, and a hollow medium is obtained.

[0009] S3, the casting solution obtained in S1 and the hollow medium obtained in S2 are injected into a spinning device, extruded from a spinneret, and formed into a membrane by instantaneous phase separation gelation in a coagulation bath by a non-solvent induced phase separation method; after sufficient phase replacement in a rinsing water bath, the membrane is heat treated in a water bath at 60-80°C for 0.5-2.5 hours, and a super-hydrophilic hollow fiber ultrafiltration membrane filament is obtained.

[0010] The foregoing super-hydrophilic hollow fiber ultrafiltration membrane filament preparation method comprises the following steps:

[0011] S1, N,N-dimethylacetamide 50-70 parts, polyvinylidene fluoride 13-20 parts, polyvinylpyrrolidone 10-15 parts, glycerol 2-6 parts, polyether 2-8 parts, end-vinyl polysiloxane 0.5-3 parts, silicon dioxide 0.5-3 parts, and chloroplatinic acid 0.01-0.5 parts are sequentially added into a stirred tank, stirred uniformly under an oil bath at 80-100°C, and a casting solution is obtained;

[0012] S2, N,N-dimethylacetamide 30-50 parts, glycerol 5-30 parts, propylene glycol block polyether 5-30 parts, and pure water 20-50 parts are added to a container, stirred uniformly at 40-70°C, and a hollow medium is obtained;

[0013] S3, the casting solution obtained in S1 and the hollow medium obtained in S2 are injected into a spinning device, extruded from a spinneret, and formed into a membrane by instantaneous phase separation gelation in a coagulation bath by a non-solvent induced phase separation method; after sufficient phase replacement in a rinsing water bath, the membrane is heat treated in a water bath at 60-80°C for 0.5-2.5 hours, and a super-hydrophilic hollow fiber ultrafiltration membrane filament is obtained.

[0014] In the foregoing super-hydrophilic hollow fiber ultrafiltration membrane filament preparation method, the propylene glycol block polyether in S1 is F38 or F68.

[0015] The preparation method of the aforementioned super-hydrophilic hollow fiber ultrafiltration membrane filament, the casting solution injection feed rate at the spinneret in S3 is 80-120 mL / min, the hollow medium injection feed rate is 20-30 mL / min, and the spinning temperature is 60-80 DEG C.

[0016] The preparation method of the aforementioned super-hydrophilic hollow fiber ultrafiltration membrane filament, the casting solution injection feed rate at the spinneret in S3 is 100 mL / min, the hollow medium injection feed rate is 25 mL / min, and the spinning temperature is 70-75 DEG C.

[0017] The preparation method of the aforementioned super-hydrophilic hollow fiber ultrafiltration membrane filament, the non-solvent induced phase separation method in S3: the extruded membrane filament at the spinneret passes through an air bath with a length of 1-30 cm, the coagulation bath temperature is 45-65 DEG C, the depth is 0.5-2.5 m, enters a rinsing water bath, and the membrane filament is collected in a bath.

[0018] The preparation method of the aforementioned super-hydrophilic hollow fiber ultrafiltration membrane filament, the non-solvent induced phase separation method in S3: the extruded membrane filament at the spinneret passes through an air bath with a length of 10-20 cm, the coagulation bath temperature is 50-60 DEG C, the depth is 1.5-2.0 m, enters a rinsing water bath, and the membrane filament is collected in a bath.

[0019] The preparation method of the aforementioned super-hydrophilic hollow fiber ultrafiltration membrane filament, after the rinsing water bath, the membrane filament is wound on a spinning reel at a speed of 10-20 m / min.

[0020] The super-hydrophilic hollow fiber ultrafiltration membrane filament prepared by any one of the aforementioned preparation methods.

[0021] The application adds propylene glycol block polyether, end vinyl polysiloxane, silicon dioxide and chloroplatinic acid to crosslink and graft polyvinylidene fluoride, so that the hydrophobic material polyvinylidene fluoride and the hydrophilic material polyvinylpyrrolidone, propylene glycol block polyether and silicon dioxide are completely crosslinked and bonded together to form a network support structure layer (such as Figure 2 ) in which the hydrophilic and hydrophobic materials are connected to each other. The functional skin layer (such as Figure 1 ) is uniform in thickness and free of defects, the membrane filament pore size range (such as Figure 3 ) is 50-90 nm, which is a relatively small pore size at present, the contact angle reaches 42 DEG, the hydrophilicity is good, and the overall cross section is a dense network support structure (such as Figure 4 ).

[0022] Compared with the prior art, the application has the following advantages:

[0023] The application provides a preparation method of super-hydrophilic hollow fiber ultrafiltration membrane filaments, which has a short process flow, few control points, stable film forming performance and is easy to mass produce. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The functional skin layer of the super-hydrophilic hollow fiber ultrafiltration membrane filaments of the application;

[0025] Figure 2 The cross-sectional network support structure layer of the super-hydrophilic hollow fiber ultrafiltration membrane filaments of the application;

[0026] Figure 3 The surface pore size distribution of the super-hydrophilic hollow fiber ultrafiltration membrane filaments of the application;

[0027] Figure 4 The overall cross section of the super-hydrophilic hollow fiber ultrafiltration membrane filaments of the application is a dense network support structure. DETAILED DESCRIPTION

[0028] Example 1: A preparation method of super-hydrophilic hollow fiber ultrafiltration membrane filaments

[0029] S1, 65 parts of N,N-dimethylacetamide (DMAC), 20 parts of polyvinylidene fluoride (PVDF), 15 parts of polyvinylpyrrolidone (PVP), 5 parts of glycerol, 2 parts of propylene glycol block polyether, 2 parts of end-vinyl polysiloxane, 1 part of silicon dioxide and 0.05 parts of chloroplatinic acid are added to a stirred tank, and stirred uniformly at 70 DEG C oil bath to obtain a casting solution;

[0030] S2, 50 parts of N,N-dimethylacetamide (DMAC), 20 parts of glycerol, 20 parts of propylene glycol block polyether F38 and 40 parts of pure water are added to a container, and stirred uniformly at 50 DEG C to obtain a hollow medium;

[0031] S3, the casting solution obtained in S1 and the hollow medium obtained in S2 are injected into a hollow fiber homogenizing spinneret, spinning is performed under the conditions of a casting solution feed rate of 100 mL / min, a hollow medium feed rate of 25 mL / min, and a spinning temperature of 25°C, an air bath with a length of 5 cm is passed through, a coagulation bath with a temperature of 65°C and a depth of 1 m is entered, a rinsing water bath is entered, the ultrafiltration membrane filaments coming out of the rinsing water bath are wound onto a spinning reel at a speed of 15 m / min, after the filaments are completely collected, heat treatment is performed in a water bath at 80°C for 0.5 hours, and an ultra-hydrophilic hollow fiber ultrafiltration membrane filament is obtained.

[0032] Performance test of the hollow fiber homogenizing ultrafiltration membrane prepared in this example: the pure water flux value is 720 L / m 2 ·h (0.1 MPa, 25°C), the tensile value is 4.5 N, the elongation rate is 220%, the contact angle is 52°, the bubble point pressure is 0.52 MPa (ethanol), and the open pore rate is 89%.

[0033] Example 2: A method for preparing an ultra-hydrophilic hollow fiber ultrafiltration membrane filament:

[0034] S1, 50 parts of N,N-dimethylacetamide (DMAC), 17 parts of polyvinylidene fluoride (PVDF), 13 parts of polyvinylpyrrolidone (PVP), 2 parts of glycerol, 8 parts of propylene glycol block polyether, 0.5 parts of vinyl-terminated polysiloxane, 3 parts of silicon dioxide, and 0.5 parts of chloroplatinic acid are added to a stirred tank, and stirring is performed under an oil bath at 90°C until a uniform casting solution is obtained;

[0035] S2, 40 parts of N,N-dimethylacetamide (DMAC), 5 parts of glycerol, 30 parts of propylene glycol block polyether F68, and 50 parts of pure water are added to a container, and stirring is performed at 70°C until a uniform hollow medium is obtained;

[0036] S3, the casting solution obtained in S1 and the hollow medium obtained in S2 are injected into a hollow fiber homogenizing spinneret, spinning is performed under the conditions of a casting solution feed rate of 80 mL / min, a hollow medium feed rate of 30 mL / min, and a spinning temperature of 25°C, an air bath with a length of 30 cm is passed through, a coagulation bath with a temperature of 55°C and a depth of 0.5 m is entered, a rinsing water bath is entered, the ultrafiltration membrane filaments coming out of the rinsing water bath are wound onto a spinning reel at a speed of 20 m / min, after the filaments are completely collected, heat treatment is performed in a water bath at 60°C for 2.5 hours, and an ultra-hydrophilic hollow fiber ultrafiltration membrane filament is obtained.

[0037] Performance test of the hollow fiber homogenizing ultrafiltration membrane prepared in this example: the pure water flux value is 650 L / m 2 ·h (0.1 MPa, 25°C), the tensile value is 4.55 N, the elongation rate is 235%, the contact angle is 50°, the bubble point pressure is 0.58 MPa (ethanol), and the open pore rate is 88%.

[0038] Example 3: A method for preparing a super-hydrophilic hollow fiber ultrafiltration membrane filament:

[0039] S1, 70 parts by mass of N,N-dimethylacetamide (DMAC), 13 parts of polyvinylidene fluoride (PVDF), 10 parts of polyvinylpyrrolidone (PVP), 6 parts of glycerol, 6 parts of propylene glycol block polyether, 3 parts of vinyl-terminated polysiloxane, 0.5 parts of silicon dioxide, 0.01 parts of chloroplatinic acid were added to a stirred tank, and stirred uniformly under an oil bath at 50°C to obtain a casting solution;

[0040] S2, 30 parts by mass of N,N-dimethylacetamide (DMAC), 15 parts of glycerol, 5 parts of propylene glycol block polyether F38 and 5 parts of pure water were added to a container, and stirred uniformly at 40°C to obtain a hollow medium;

[0041] S3, the casting solution obtained in S1 and the hollow medium obtained in S2 were injected into a hollow fiber homogenizing spinneret, and spun under the conditions of a casting solution feed rate of 120 mL / min, a hollow medium feed rate of 20 mL / min, and a spinning temperature of 25°C. After an air bath with a length of 1 cm, the ultrafiltration membrane filament was immersed in a coagulation bath with a temperature of 45°C and a depth of 2.5 m, and then immersed in a rinsing water bath. The ultrafiltration membrane filament coming out of the rinsing water bath was wound onto a spinning reel at a speed of 10 m / min. After the spinning was completed, the ultrafiltration membrane filament was heat treated in a water bath at 70°C for 1.5 hours to obtain a super-hydrophilic hollow fiber ultrafiltration membrane filament.

[0042] The performance test of the hollow fiber homogenizing ultrafiltration membrane prepared in this example showed that the pure water flux value was 890 L / m 2 ·h (0.1 MPa, 25°C), the tensile value was 3.6 N, the elongation rate was 185%, the contact angle was 48°, the bubble point pressure was 0.48 MPa (ethanol), and the open porosity was 91%.

[0043] Example 4: A method for preparing a super-hydrophilic hollow fiber ultrafiltration membrane filament:

[0044] S1, 60 parts by mass of N,N-dimethylacetamide (DMAC), 15 parts of polyvinylidene fluoride (PVDF), 12 parts of polyvinylpyrrolidone (PVP), 4 parts of glycerol, 4 parts of propylene glycol block polyether, 1 part of vinyl-terminated polysiloxane, 2 parts of silicon dioxide, and 0.2 parts of chloroplatinic acid were added to a stirred tank, and stirred uniformly under an oil bath at 80°C to obtain a casting solution;

[0045] S2, 35 parts by mass of N,N-dimethylacetamide (DMAC), 25 parts of glycerol, 20 parts of propylene glycol block polyether, and 30 parts of pure water were added to a container, and stirred uniformly at 60°C to obtain a hollow medium;

[0046] S3, the casting solution obtained in S1 and the hollow medium obtained in S2 are injected into a hollow fiber homogenizing spinneret, spinning is performed under the conditions of a casting solution feed rate of 100 mL / min, a hollow medium feed rate of 25 mL / min, and a spinning temperature of 25°C, an air bath with a length of 10 cm is passed through, a coagulation bath with a temperature of 60°C and a depth of 2.0 m is entered, a rinsing water bath is entered, the ultrafiltration membrane filaments coming out of the rinsing water bath are wound onto a spinning reel at a speed of 15 m / min, and after the filaments are completely collected, heat treatment is performed in a water bath at 75°C for 1.0 hour, thereby obtaining the super-hydrophilic hollow fiber ultrafiltration membrane filaments.

[0047] Performance test of the hollow fiber homogenizing ultrafiltration membrane prepared in this example: the pure water flux value is 700 L / m 2 ·h (0.1 MPa, 25°C), the tensile value is 3.9 N, the elongation is 200%, the contact angle is 42°, the bubble point pressure is 0.54 MPa (ethanol), and the open pore rate is 90%.

[0048] Example 5: A method for preparing super-hydrophilic hollow fiber ultrafiltration membrane filaments:

[0049] S1, 55 parts of N,N-dimethylacetamide (DMAC), 19 parts of polyvinylidene fluoride (PVDF), 13 parts of polyvinylpyrrolidone (PVP), 3 parts of glycerol, 5 parts of propylene glycol block polyether, 1.5 parts of vinyl-terminated polysiloxane, 1.5 parts of silicon dioxide, and 0.08 parts of chloroplatinic acid are added to a stirred tank, and stirring is performed under an oil bath at 60°C until uniformity is achieved, thereby obtaining a casting solution;

[0050] S2, 45 parts of N,N-dimethylacetamide (DMAC), 30 parts of glycerol, 10 parts of propylene glycol block polyether, and 35 parts of pure water are added to a container, and stirring is performed at 55°C until uniformity is achieved, thereby obtaining a hollow medium;

[0051] S3, the casting solution obtained in S1 and the hollow medium obtained in S2 are injected into a hollow fiber homogenizing spinneret, spinning is performed under the conditions of a casting solution feed rate of 100 mL / min, a hollow medium feed rate of 25 mL / min, and a spinning temperature of 25°C, an air bath with a length of 20 cm is passed through, a coagulation bath with a temperature of 50°C and a depth of 1.5 m is entered, a rinsing water bath is entered, the ultrafiltration membrane filaments coming out of the rinsing water bath are wound onto a spinning reel at a speed of 15 m / min, and after the filaments are completely collected, heat treatment is performed in a water bath at 65°C for 2.0 hours, thereby obtaining the super-hydrophilic hollow fiber ultrafiltration membrane filaments.

[0052] Performance test of the hollow fiber homogenizing ultrafiltration membrane prepared in this example: the pure water flux value is 560 L / m 2• h (0.1 MPa, 25°C) with a tensile value of 4.7 N, an elongation of 260%, a contact angle of 55°, a bubble point pressure of 0.6 MPa (ethanol), and an open porosity of 86%.

Claims

1. A method for preparing a super hydrophilic hollow fiber ultrafiltration membrane, characterized in that: The following steps are involved: S1. By mass, 50-70 parts of N,N-dimethylacetamide, 13-20 parts of polyvinylidene fluoride, 10-15 parts of polyvinyl pyrrolidone, 2-6 parts of glycerol, 2-8 parts of polyether, 0.5-3 parts of vinyl-terminated polysiloxane, 0.5-3 parts of silicon dioxide, and 0.01-0.5 parts of chloroplatinic acid are added to a stirring vessel in sequence, and stirred evenly in an oil bath at 85-100° C. to obtain a casting solution; S2. Add 30 to 50 parts by mass of N,N-dimethylacetamide, 5 to 30 parts by mass of propylene glycol, 5 to 30 parts by mass of propylene glycol block polyether, and 20 to 50 parts by mass of pure water into a container, and stir uniformly at 40 to 70° C. to obtain a hollow medium; S3. The casting liquid obtained in S1 and the hollow medium obtained in S2 are injected into the spinning device and extruded from the spinneret. The membrane is formed into a gel by instantaneous phase separation in the coagulation bath through a non-solvent induced phase separation method. After sufficient phase replacement in a rinsing water bath, the membrane is heat-treated in a water bath at 60 to 80°C for 0.5 to 2.5 hours to obtain super hydrophilic hollow fiber ultrafiltration membrane filaments.

2. The method for preparing a super hydrophilic hollow fiber ultrafiltration membrane according to claim 1, wherein: The propylene glycol block polyether in S1 is F38 and F68.

3. The method for preparing super hydrophilic hollow fiber ultrafiltration membrane according to claim 1, characterized in that: In S3, the injection rate of the casting solution at the spinneret is 80-120 mL / min, the injection rate of the hollow medium is 20-30 mL / min, and the spinning temperature is 60-80°C.

4. The method for preparing super hydrophilic hollow fiber ultrafiltration membrane according to claim 1, characterized in that: The injection rate of the casting solution at the spinneret in S3 is 100 mL / min, the injection rate of the hollow medium is 25 mL / min, and the spinning temperature is 70-75°C.

5. The method for preparing super hydrophilic hollow fiber ultrafiltration membrane according to claim 1, characterized in that: The non-solvent induced phase separation method described in S3: the membrane fibers extruded from the spinneret pass through an air bath with a length of 1 to 30 cm, a coagulation bath with a temperature of 45 to 65°C and a depth of 0.5 to 2.5 m, and then enter a rinsing water bath and a collecting bath.

6. The method for preparing super hydrophilic hollow fiber ultrafiltration membrane according to claim 1, characterized in that: The non-solvent induced phase separation method described in S3: the membrane fibers extruded from the spinneret pass through an air bath with a length of 10 to 20 cm, a coagulation bath with a temperature of 50 to 60°C and a depth of 1.5 to 2.0 m, and then enter a rinsing water bath and a collecting bath.

7. The method for preparing a super hydrophilic hollow fiber ultrafiltration membrane according to claim 5 or 6, characterized in that: After the rinsing water bath, the membrane filaments are wound onto a winding wheel at a speed of 10 to 20 m / min.

8. Super hydrophilic hollow fiber ultrafiltration membrane obtained by the preparation method according to any one of claims 1 to 7.

Images