Hydrophilic TA (at) H-UiO-66 (at) PANI / PVDF membrane as well as preparation method and application thereof

Abstract

The invention discloses a hydrophilic TA (at) H-UiO-66 (at) PANI / PVDF (Polyvinylidene Fluoride) membrane as well as a preparation method and application thereof, the conception of the preparation method is that H-UiO-66 is modified by tannic acid and connected with aniline, and the aniline is polymerized and deposited on the surface of the membrane to prepare the membrane with high flux and pollution resistance; compared with a traditional PVDF membrane, the hydrophilic TA-coated H-UiO-66-coated PANI / PVDF membrane has the advantages that a transmission channel is added, and the flux of the membrane is improved; tA is utilized to modify H-UiO-66, abundant hydrophilic functional groups are introduced, and the super-oleophobicity of polyaniline in water can repel hydrophobic dirt, so that the pollution resistance of the membrane is improved, the service life of the membrane is prolonged, and the flux recovery rate is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of membrane separation, and particularly relates to a hydrophilic

[0002] TA@H-UiO-66@PANI / PVDF membrane and a preparation method thereof. Background Art

[0003] In recent years, treating wastewater to meet specific water quality requirements has become one of the important ways to alleviate the shortage of water resources. Membrane technology has gradually become a popular separation technology due to its advantages such as simple operation and high-quality effluent water, and has been applied in many fields. Among them, polyvinylidene fluoride (PVDF) is one of the commonly used polymer organic membrane materials, which has characteristics such as good chemical resistance, high mechanical strength, and good film-forming property, so it is widely used in the field of water treatment. However, PVDF membranes have problems of poor hydrophilicity and easy fouling. Therefore, it is of great significance to prepare a membrane with high flux, hydrophilicity, and anti-fouling properties. Summary of the Invention

[0004] The present invention proposes a hydrophilic TA@H-UiO-66@PANI / PVDF membrane and a preparation method thereof for the above problems. The idea is to use H-UiO-66 material as the main substance for membrane modification to prepare a modified membrane.

[0005] Metal-organic framework (MOFs) materials have excellent properties such as high porosity, regular pore channels, and many adsorption sites. UiO-66 has excellent hydrothermal stability and chemical stability, and is expected to break through the practical application of MOF materials in industry. Introducing large-pore H-UiO-66 into the field of membrane research has obtained unexpected effects and can provide additional transport channels. Tannic acid has abundant phenolic hydroxyl groups. In addition to providing hydrophilic groups, it usually plays the role of an anchor to fix the modified layer on the membrane surface. Conjugated polyaniline affects the field of water filtration membranes due to its hydrophilicity and antibacterial properties, simple and inexpensive synthesis method, heat resistance and acid resistance, and unique doping / dedoping chemical properties.

[0006] The present invention modifies H-UiO-66 with tannic acid and connects it with aniline, and uses aniline polymerization to deposit on the membrane surface to prepare a membrane with high flux and anti-fouling properties. To achieve the object of the present invention, the present invention proposes the following technical solutions.

[0007] In a first aspect, the present invention proposes a preparation method of a hydrophilic TA@H-UiO-66@PANI / PVDF membrane, comprising the following steps:

[0008] (1) Dissolve benzoic acid, zirconium chloride, and terephthalic acid in N,N-dimethylformamide respectively. After ultrasonic dissolution, transfer them to a high-pressure reactor for reaction. The reaction temperature is 100°C to 150°C, and the reaction time is 12h to 36h. Wash the reaction product and then immerse it in an acidic solution for reaction. Centrifuge the reaction solution to obtain the precipitate, and then wash it with N,N-dimethylformamide and absolute ethanol respectively, centrifuge, take out the solid reaction product, and dry it to obtain large-pore H-UiO-66.

[0009] The mass ratio of the benzoic acid, zirconium chloride, and terephthalic acid is 1.7 - 1.9:0.15 - 0.17:0.1 - 0.12.

[0010] (2) Disperse the large-pore H-UiO-66 prepared in step (1) in an aqueous tannic acid solution for reaction for 0.5h to 6h. After centrifugation and drying, obtain TA@H-UiO-66.

[0011] The theoretical mass ratio of the H-UiO-66 to tannic acid in the aqueous tannic acid solution is 0.5 - 1.5:1. The concentration of the aqueous tannic acid solution is 0.5 - 2g / L.

[0012] (3) Dissolve aniline fully in a hydrochloric acid solution with a concentration of 0.05 - 0.1mol / L to make an aniline solution. Then disperse the TA@H-UiO-66 prepared in step (2) in the aniline solution and stir. Dropwise add ammonium persulfate solution for reaction, which lasts for 0.5h to 6h. Centrifuge, collect the precipitate, and dry to obtain TA@H-UiO-66@PANI.

[0013] The theoretical mass ratio of the aniline, ammonium persulfate in the ammonium persulfate solution, and TA@H-UiO-66 prepared in step (2) is 1:1 - 5:0.1 - 1. The concentration of the aniline solution is 1 - 10g / L.

[0014] (4) Prepare an N,N-dimethylformamide solution of PVDF with a concentration of 15 - 21wt%. Add the TA@H-UiO-66@PANI prepared in step (3) to form a modified PVDF casting solution. Stir the modified PVDF casting solution overnight at room temperature to make it fully dispersed, and then let it stand to remove air bubbles to form a uniform polymer solution. At 10 - 25°C, use a film doctor to cast the uniform polymer solution on a glass plate, and then immerse it in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane.

[0015] The mass ratio of the PVDF to TA@H-UiO-66@PANI is 1:0.025 - 0.1.

[0016] Further, the thickness of the uniform polymer solution cast on the glass plate in step (4) is 200 μm.

[0017] Further, in step (4), the modified PVDF casting solution is first ultrasonically treated for 0.5 - 1 h and then left standing for 8 - 12 h. The role of ultrasonic treatment is to remove bubbles from the solution more quickly. There is no requirement for power. Compared with not performing ultrasonic treatment, the standing time can be shortened when ultrasonic treatment is performed.

[0018] Further, the acidic solution described in step (1) is one or more of hydrochloric acid, sulfuric acid, and nitric acid. Here, the acidic solution is preferably 0.1 mol / L hydrochloric acid solution;

[0019] Further, for the preparation method of the hydrophilic TA@H-UiO-66@PANI / PVDF membrane described in the present invention, the drying in steps (1), (2), and (3) is vacuum drying at 60 °C.

[0020] Further, the reaction temperature of the high-pressure reactor described in step (1) is 120 °C, and the reaction time is 24 h; the mass ratio of benzoic acid, zirconium chloride, and terephthalic acid is 1.832:0.166:0.12;

[0021] In step (2), the reaction time for the large-pore H-UiO-66 dispersed in the tannic acid aqueous solution is 1 h;

[0022] The theoretical mass ratio of H-UiO-66 to tannic acid in the tannic acid aqueous solution described in step (2) is 1:1; the concentration of the tannic acid aqueous solution is 1 g / L;

[0023] In step (3), the concentration of the hydrochloric acid solution is 0.1 mol / L, and the reaction time for TA@H-UiO-66 dispersed in the aniline solution and stirred with ammonium persulfate added dropwise is 0.5 h;

[0024] The theoretical mass ratio of aniline, ammonium persulfate in the ammonium persulfate solution, and TA@H-UiO-66 prepared in step (2) is 0.93:2.28:0.085; the concentration of the aniline solution is 5 g / L;

[0025] In step (4), the mass ratio of PVDF contained in the modified PVDF casting solution to TA@H-UiO-66@PANI is 1:0.025 - 0.1.

[0026] In the second aspect, the present invention provides the product of the above preparation method, a hydrophilic

[0027] TA@H-UiO-66@PANI / PVDF membrane.

[0028] Preferably, the hydrophilic TA@H-UiO-66@PANI / PVDF membrane is a hollow fiber membrane or a flat membrane.

[0029] In a third aspect, the present invention provides an application of the product of the preparation method of the hydrophilic TA@H-UiO-66@PANI / PVDF membrane as a microfiltration membrane in wastewater treatment.

[0030] The beneficial effects of the present invention are as follows: introducing H-UiO-66 on the surface of the PVDF membrane increases the transport channels and improves the membrane flux; modifying H-UiO-66 with TA introduces rich hydrophilic functional groups, and the superhydrophobicity of polyaniline in water can repel hydrophobic fouling, which helps to improve the anti-fouling property of the membrane and extend the service life of the membrane, as reflected by a greatly improved flux recovery rate. Detailed Embodiments

[0031] The present invention will be described in detail below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Any variations within the scope of the present invention should be included in the technical scope of the present invention.

[0032] In the following embodiments, the performance of the membrane is evaluated by two parameters: pure water flux (J) and flux recovery rate (FRR). The water flux is the volume of water passing through a unit membrane area per unit time under a unit pressure. Usually, for the test of ultrafiltration membranes, the pressure of water is set under the same pressure conditions; it is calculated using the following formula:

[0033]

[0034] where J W is the pure water flux (L / m 2 ·h), V w is the volume of pure water filtered (L), A is the effective filtration area (m 2 ), Δt is the time used (h), J w1 is the water flux at the initial filtration of pure water (L / m 2 ·h), and J w2 is the water flux of pure water after filtering the bovine serum albumin solution and rinsing with water (L / m 2 ·h). The flux recovery rate (FRR) is the percentage of the membrane flux restored to its initial flux during the membrane separation process. It reflects the recovery ability of the membrane after fouling and is one of the important indicators to measure the membrane performance. The higher the FRR value, the better the flux recovery rate. The definition and calculation method of the flux recovery rate are as follows:

[0035]

[0036] In the formula, FRR is the flux recovery, and JW2 is the flux of the membrane after cleaning, J W1 is the initial flux of the membrane.

[0037] rate

[0038] Example 1

[0039] (1) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to prepare a PVDF solution with a mass fraction of 17%. Stir the solution overnight at room temperature to completely disperse it, then ultrasonically treat it for half an hour before use and let it stand for 12 h to remove air bubbles. Then, at room temperature, use a film doctor blade to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to obtain a PVDF membrane. Measure the pure water flux of the original membrane under the same transmembrane pressure (0.1 MPa). After pre-pressing the ultrafiltration membrane for 30 min at 0.1 MPa in a pure aqueous solution to obtain a stable flux, the effective membrane area is about 9 cm 2 .

[0040] First, measure the initial flux by pure water filtration for 30 min (measure a set of data every five minutes on average, a total of six groups to obtain the average value), and then replace pure water with a BSA solution with a concentration of 1 g / L to measure for 60 min (measure a set of data every ten minutes on average, a total of six groups to obtain the average value); then thoroughly rinse the membrane surface with deionized water to remove reversibly adsorbed proteins for 30 min; finally, filter the rinsed membrane with pure water for 30 min (measure a set of data every five minutes on average, a total of six groups to obtain the average value), and repeat the above steps for the second dynamic filtration cycle.

[0041] For the prepared PVDF membrane, at room temperature and 0.1 MPa, the pure water flux is 115 L / m 2 ·h, and the flux recovery rate is 52.17%, as shown in Table 1 for details.

[0042] Example 2

[0043] (1) Dissolve 1.832 g of benzoic acid in 20 mL of DMF. After complete dissolution, add 0.166 g of terephthalic acid and 0.12 g of zirconium chloride and dissolve them. Transfer the dissolved solution to a reaction kettle and react at 120 °C for 24 h. Wash twice with DMF and then disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to obtain the precipitate, and wash it by centrifugation with DMF and ethanol respectively, repeating the washing 3 times to obtain H-UiO-66 with large pore size. (2) Dissolve 0.1 g of TA in 100 mL of water, adjust the pH to 8.5, then add 0.1 g of H-UiO-66, stir for 1 h and then centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93 g of aniline in 200 mL of 0.1 mol / L HCl solution, add 0.085 g of TA@H-UiO-66 and stir to disperse. Dissolve 2.28 g of ammonium persulfate in 10 mL of 0.1 mol / L HCl solution, and gradually add it dropwise to the aniline solution containing TA@H-UiO-66. React for 0.5 h, centrifuge and collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to prepare a 17 wt% PVDF N,N-dimethylformamide solution. Add 0.085 g of TA@H-UiO-66@PANI to form a modified PVDF casting solution. Stir the solution overnight at room temperature to make it completely dispersed, then ultrasonically treat it for half an hour before use and let it stand for 12 h to remove air bubbles. Then, at room temperature, use a film doctor to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane.

[0044] Measure the pure water flux of the modified membrane at a transmembrane pressure of 0.1 MPa. After pre-pressing the ultrafiltration membrane in pure aqueous solution at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area is about 9 cm 2 .

[0045] Then, conduct two consecutive dynamic filtration cycles on the modified membrane at the same transmembrane pressure of 0.1 MPa. First, measure the pure water filtration for 30 min (measure a set of data every five minutes on average, a total of six sets to obtain the average value) to obtain the initial flux, and then replace the pure water with a 1 g / L BSA solution and measure for 60 min (measure a set of data every ten minutes on average, a total of six sets to obtain the average value); then thoroughly rinse the membrane surface with deionized water for 30 min to remove reversibly adsorbed proteins; finally, filter the rinsed membrane with pure water for 30 min (measure a set of data every five minutes on average, a total of six sets to obtain the average value) to complete the first dynamic filtration cycle, and repeat the above steps to conduct the second dynamic filtration cycle.

[0046] The prepared TA@H-UiO-66@PANI / PVDF membrane has a pure water flux of 612 L / m 2 ·h and a flux recovery rate of 76.58% at room temperature and 0.1 MPa, as shown in Table 1.

[0047] Example 3

[0048] (1) Dissolve 1.832 g of benzoic acid in 20 mL of DMF. After complete dissolution, add 0.166 g of terephthalic acid and 0.12 g of zirconium chloride and dissolve them. Transfer the dissolved solution to a reaction kettle and react at 120 °C for 24 h. After washing twice with DMF, disperse it in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to obtain the precipitate, and centrifuge and wash it with DMF and ethanol respectively, repeating the washing 3 times to obtain macroporous H-UiO-66. (2) Dissolve 0.1 g of TA in 100 mL of water, adjust the pH to 8.5, then add 0.1 g of H-UiO-66, stir for 1 h, and then centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93 g of aniline in 200 mL of 0.1 mol / L HCl solution, add 0.085 g of TA@H-UiO-66 and stir to disperse. Dissolve 2.28 g of ammonium persulfate in 10 mL of 0.1 mol / L HCl solution, and gradually add it dropwise to the aniline solution containing TA@H-UiO-66. React for 0.5 h, centrifuge, and collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to obtain a 17 wt% PVDF N,N-dimethylformamide solution, and then add 0.136 g of TA@H-UiO-66@PANI to prepare a modified PVDF casting solution. Stir the modified PVDF casting solution overnight at room temperature to completely disperse it, then ultrasonically treat it for half an hour before use, and let it stand for 12 h to remove air bubbles. Then, at room temperature, use a film doctor to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane. Measure the pure water flux of the modified membrane under the same transmembrane pressure (0.1 MPa). After pre-pressing the ultrafiltration membrane in pure aqueous solution at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area is about 9 cm 2 .

[0049] Then, two consecutive dynamic filtration cycles were performed on the modified membrane at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by measuring the pure water filtration for 30 min (an average of one set of data was measured every five minutes, and a total of six sets of data were obtained for averaging), and then the BSA solution with a concentration of 1 g / L was used instead of pure water to measure for 60 min (an average of one set of data was measured every ten minutes, and a total of six sets of data were obtained for averaging); then the membrane surface was thoroughly rinsed with deionized water for 30 min to remove reversibly adsorbed proteins; finally, the rinsed membrane was filtered with pure water for 30 min (an average of one set of data was measured every five minutes, and a total of six sets of data were obtained for averaging), completing the first dynamic filtration cycle; the above steps were repeated for the second dynamic filtration cycle.

[0050] The prepared TA@H-UiO-66@PANI / PVDF membrane had a pure water flux of 619 L / m 2 ·h and a flux recovery rate of 80.43%, as shown in Table 1 for details.

[0051] Example 4

[0052] (1) Dissolve 1.832 g of benzoic acid in 20 mL of DMF. After complete dissolution, add 0.166 g of terephthalic acid and 0.12 g of zirconium chloride and dissolve them. Transfer the dissolved solution to a reaction kettle and react at 120 °C for 24 h. Wash twice with DMF and then disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to obtain the precipitate, and centrifuge with DMF and ethanol respectively, repeating the washing 3 times to obtain H-UiO-66 with large pore size. (2) Dissolve 0.1 g of TA in 100 mL of water. After adjusting the pH to 8.5, add 0.1 g of H-UiO-66 and stir for 1 h, then centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93 g of aniline in 200 mL of 0.1 mol / L HCl solution, add 0.085 g of TA@H-UiO-66 and stir to disperse. Dissolve 2.28 g of ammonium persulfate in 10 mL of 0.1 mol / L HCl solution and add it dropwise to the aniline solution containing TA@H-UiO-66. React for 0.5 h, centrifuge and wash, and collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to obtain a 17 wt% PVDF N,N-dimethylformamide solution. Add 0.17 g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution overnight at room temperature to completely disperse it, then ultrasonically treat it for half an hour before use and let it stand for 12 h to remove bubbles. Then, at room temperature, use a film doctor blade to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane. Measure the pure water flux of the modified membrane under the same transmembrane pressure (0.1 MPa). After pre-pressing the ultrafiltration membrane in pure aqueous solution at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area is about 9 cm 2 .

[0053] Then, conduct two consecutive dynamic filtration cycles on the modified membrane under the same transmembrane pressure of 0.1 MPa. First, measure the pure water filtration for 30 min (measure a set of data every five minutes on average, a total of six sets to obtain the average value) to obtain the initial flux, and then replace the pure water with a 1 g / L BSA solution and measure for 60 min (measure a set of data every ten minutes on average, a total of six sets to obtain the average value); then thoroughly rinse the membrane surface with deionized water for 30 min to remove reversibly adsorbed proteins; finally, filter the rinsed membrane with pure water for 30 min (measure a set of data every five minutes on average, a total of six sets to obtain the average value) to complete the first dynamic filtration cycle; repeat the above steps for the second dynamic filtration cycle.

[0054] The prepared TA@H-UiO-66@PANI / PVDF membrane has a pure water flux of 624 L / m 2 ·h and a flux recovery rate of 82.55% at room temperature and 0.1 MPa, as shown in Table 1.

[0055] Example 5

[0056] (1) Dissolve 1.832 g of benzoic acid in 20 mL of DMF. After complete dissolution, add 0.166 g of terephthalic acid and 0.12 g of zirconium chloride and dissolve. Transfer the dissolved solution to a reaction kettle and react at 120 °C for 24 h. Wash twice with DMF and disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to obtain the precipitate, and centrifuge with DMF and ethanol respectively, repeating the washing 3 times to obtain large-pore H-UiO-66. (2) Dissolve 0.1 g of TA in 100 mL of water, adjust the pH to 8.5, then add 0.1 g of H-UiO-66, stir for 1 h and then centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93 g of aniline in 200 mL of 0.1 mol / L HCl solution, add 0.085 g of TA@H-UiO-66 and stir to disperse. Dissolve 2.28 g of ammonium persulfate in 10 mL of 0.1 mol / L HCl solution and add it dropwise to the aniline solution containing TA@H-UiO-66, react for 0.5 h, centrifuge and wash, collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to obtain a 17 wt% PVDF N,N-dimethylformamide solution, add 0.204 g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution overnight at room temperature to completely disperse it, then ultrasonically treat it for half an hour before use and let it stand for 12 h to remove bubbles. Then, at room temperature, use a film doctor to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane. Measure the pure water flux of the modified membrane under the same transmembrane pressure (0.1 MPa). After pre-pressing the ultrafiltration membrane in pure aqueous solution at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area is about 9 cm 2 . The test time is 120 minutes, and it is measured every ten minutes to obtain the average flux to minimize experimental errors.

[0057] Then, two consecutive dynamic filtration cycles were carried out on the modified membrane at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by measuring the pure water filtration for 30 min (an average of one set of data was measured every five minutes, and a total of six sets of data were obtained for the average value), and then the BSA solution with a concentration of 1 g / L was used instead of pure water to measure for 60 min (an average of one set of data was measured every ten minutes, and a total of six sets of data were obtained for the average value); then the membrane surface was thoroughly rinsed with deionized water for 30 min to remove reversibly adsorbed proteins; finally, the rinsed membrane was filtered with pure water for 30 min (an average of one set of data was measured every five minutes, and a total of six sets of data were obtained for the average value), completing the first dynamic filtration cycle; repeat the above steps to carry out the second dynamic filtration cycle.

[0058] The prepared TA@H-UiO-66@PANI / PVDF membrane had a pure water flux of 498 L / m 2 ·h and a flux recovery rate of 81.49% at room temperature and 0.1 MPa, as shown in Table 1 for details.

[0059] Example 5

[0060] (1) Dissolve 1.832 g of benzoic acid in 20 mL of DMF. After complete dissolution, add 0.166 g of terephthalic acid and 0.12 g of zirconium chloride and dissolve them. Transfer the dissolved solution to a reaction kettle and react at 120 °C for 24 h. Wash twice with DMF and disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to obtain the precipitate, and centrifuge with DMF and ethanol respectively, and repeat the washing 3 times to obtain large-pore H-UiO-66. (2) Dissolve 0.1 g of TA in 100 mL of water, adjust the pH to 8.5, then add 0.1 g of H-UiO-66, stir for 1 h and then centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93 g of aniline in 200 mL of 0.1 mol / L HCl solution, add 0.085 g of TA@H-UiO-66 and stir to disperse. Dissolve 2.28 g of ammonium persulfate in 10 mL of 0.1 mol / L HCl solution, and gradually add it dropwise to the aniline solution containing TA@H-UiO-66. React for 0.5 h, centrifuge and wash, and collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to obtain a 17 wt% PVDF N,N-dimethylformamide solution. Add 0.204 g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution overnight at room temperature to completely disperse it, then ultrasonically treat it for half an hour before use, and let it stand for 12 h to remove air bubbles. Then, at room temperature, use a film doctor blade to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane. Measure the pure water flux of the modified membrane under the same transmembrane pressure (0.1 MPa). After pre-pressing the ultrafiltration membrane in a pure aqueous solution at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area is about 9 cm 2 . The test time is 120 minutes, and it is measured every ten minutes to obtain the average flux to minimize experimental errors.

[0061] Then, conduct two consecutive dynamic filtration cycles on the modified membrane under the same transmembrane pressure of 0.1 MPa. First, measure the pure water filtration for 30 min (measure a set of data every five minutes on average, a total of six groups to obtain the average value) to obtain the initial flux, and then replace the pure water with a 1 g / L BSA solution and measure for 60 min (measure a set of data every ten minutes on average, a total of six groups to obtain the average value); then thoroughly rinse the membrane surface with deionized water to remove reversibly adsorbed proteins for 30 min; finally, filter the rinsed membrane with pure water for 30 min (measure a set of data every five minutes on average, a total of six groups to obtain the average value) to complete the first dynamic filtration cycle; repeat the above steps for the second dynamic filtration cycle.

[0062] The prepared TA@H-UiO-66@PANI / PVDF membrane has a pure water flux of 498 L / m 2 ·h at room temperature and 0.1 MPa, and the flux recovery rate is 81.56%. See Table 1 for details.

[0063] Example 6

[0064] (1) Dissolve 1.832 g of benzoic acid in 20 mL of DMF. After complete dissolution, add 0.166 g of terephthalic acid and 0.12 g of zirconium chloride and dissolve them. Transfer the dissolved solution to a reaction kettle and react at 120 °C for 24 h. After washing twice with DMF, disperse it in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to obtain the precipitate, and centrifuge it with DMF and ethanol respectively, and repeat the washing 3 times to obtain large-pore H-UiO-66. (2) Dissolve 0.1 g of TA in 100 mL of water, adjust the pH to 8.5, then add 0.1 g of H-UiO-66, stir for 1 h and then centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93 g of aniline in 200 mL of 0.1 mol / L HCl solution, add 0.085 g of TA@H-UiO-66 and stir to disperse. Dissolve 2.28 g of ammonium persulfate in 10 mL of 0.1 mol / L HCl solution, and add it dropwise to the aniline solution containing TA@H-UiO-66. React for 0.5 h, centrifuge and wash, and collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to obtain a 17 wt% PVDF N,N-dimethylformamide solution, add 0.255 g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution overnight at room temperature to make it completely dispersed, then ultrasonically treat it for half an hour before use, and let it stand for 12 h to remove bubbles. Then, at room temperature, use a film doctor to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane. Measure the pure water flux of the modified membrane under the same transmembrane pressure (0.1 MPa). After pre-pressing the ultrafiltration membrane in pure aqueous solution at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area is about 9 cm 2 . The test time is 120 minutes, and it is measured every ten minutes to obtain the average flux to minimize experimental errors.

[0065] Then, two consecutive dynamic filtration cycles were performed on the modified membrane at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by measuring the pure water filtration for 30 min (a total of six groups of data were measured every five minutes on average and the average value was obtained), and then the BSA solution with a concentration of 1 g / L was used instead of pure water to measure for 60 min (a total of six groups of data were measured every ten minutes on average and the average value was obtained); then the membrane surface was thoroughly rinsed with deionized water for 30 min to remove reversibly adsorbed proteins; finally, the rinsed membrane was filtered with pure water for another 30 min (a total of six groups of data were measured every five minutes on average and the average value was obtained), completing the first dynamic filtration cycle; the above steps were repeated to perform the second dynamic filtration cycle.

[0066] The prepared TA@H-UiO-66@PANI / PVDF membrane had a pure water flux of 322 L / m 2 ·h and a flux recovery rate of 81.79%, as shown in Table 1 for details.

[0067] Example 7

[0068] (1) Dissolve 1.832 g of benzoic acid in 20 mL of DMF. After complete dissolution, add 0.166 g of terephthalic acid and 0.12 g of zirconium chloride and dissolve them. Transfer the dissolved solution to a reaction kettle and react at 120 °C for 24 h. After washing twice with DMF, disperse it in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to obtain the precipitate, and centrifuge it with DMF and ethanol respectively, repeating the washing three times to obtain macroporous H-UiO-66. (2) Dissolve 0.1 g of TA in 100 mL of water. After adjusting the pH to 8.5, add 0.1 g of H-UiO-66 and stir for 1 h, then centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93 g of aniline in 200 mL of 0.1 mol / L HCl solution, add 0.085 g of TA@H-UiO-66 and stir to disperse. Dissolve 2.28 g of ammonium persulfate in 10 mL of 0.1 mol / L HCl solution, and gradually add it dropwise to the aniline solution containing TA@H-UiO-66. React for 0.5 h, centrifuge and wash, and collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4 g of PVDF polymer powder in 17.58 ml of N,N-dimethylformamide solvent to obtain a 17 wt% PVDF N,N-dimethylformamide solution. Add 0.34 g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution overnight at room temperature to completely disperse it, then ultrasonically treat it for half an hour before use and let it stand for 12 h to remove bubbles. Then, at room temperature, use a film doctor to cast a uniform polymer solution with a thickness of 200 μm on a glass plate, and then immerse the glass plate in water for solvent exchange for 1 day to prepare the TA@H-UiO-66@PANI / PVDF membrane.

[0069] Measure the pure water flux of the modified membrane under the same transmembrane pressure (0.1 MPa). After pre-pressing the ultrafiltration membrane in pure aqueous solution at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area is about 9 cm 2 .

[0070] Then, conduct two consecutive dynamic filtration cycles on the modified membrane under the same transmembrane pressure of 0.1 MPa. First, measure the pure water filtration for 30 min (average of one set of data every five minutes, a total of six sets to obtain the average value) to obtain the initial flux, and then replace the pure water with a 1 g / L BSA solution and measure for 60 min (average of one set of data every ten minutes, a total of six sets to obtain the average value); then thoroughly rinse the membrane surface with deionized water for 30 min to remove reversibly adsorbed proteins; finally, filter the rinsed membrane with pure water for 30 min (average of one set of data every five minutes, a total of six sets to obtain the average value) to complete the first dynamic filtration cycle; repeat the above steps to conduct the second dynamic filtration cycle.

[0071] The prepared TA@H-UiO-66@PANI / PVDF membrane has a pure water flux of 185 L / m 2 ·h at room temperature and 0.1 MPa, and the flux recovery rate is 80.13%. See Table 1 for details.

[0072] Table 1: Performance test of the membrane

[0073]

[0074] At a working pressure of 0.1 MPa, the pure water flux of the membrane in Example 1 is 115 L / m 2 ·h. The membrane flux of Example 4 reaches 624 L / m 2 ·h. However, as the concentration of the TA@H-UiO-66@PANI material increases, the pure water flux of the ultrafiltration membrane first increases and then decreases. The pure water flux of the membrane in Example 7 is only 185 L / m 2 ·h. During the dynamic anti-fouling performance test, the anti-fouling performance of the membrane was studied by using multi-cycle filtration operation of 0.1 g / L BSA aqueous solution. The flux recovery rate of the membrane in Example 4 can reach 82.55%. It can be concluded that the modified membrane flux is greatly improved, and the anti-fouling performance is also improved. When the addition amount of the TA@H-UiO-66@PANI material is that of Example 4, the performance of the membrane is the best.

Claims

1. A method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane, comprising the following steps: (1) Dissolving benzoic acid, zirconium chloride and terephthalic acid in N,N-dimethylformamide respectively, transferring to a high-pressure reactor for reaction after ultrasonic dissolution, the reaction temperature is 100°C to 150°C, and the reaction time is 12h to 36h; washing the reaction product and immersing it in an acidic solution for reaction, centrifuging the reaction solution to obtain a precipitate, and then washing it with N,N-dimethylformamide and anhydrous ethanol respectively, centrifuging, taking out the solid reaction product, and drying it to obtain large-pore H-UiO-66; The mass ratio of the benzoic acid, zirconium chloride and terephthalic acid is 1.7-1.9: 0.15-0.17: 0.1-0.12 (2) dispersing the large-pore H-UiO-66 prepared in step (1) in a tannic acid aqueous solution for reaction for 0.5 h to 6 h, and centrifugally drying to obtain TA@H-UiO-66; The theoretical mass ratio of the H-UiO-66 to the tannic acid in the tannic acid aqueous solution is 0.5-1.5:1; the concentration of the tannic acid aqueous solution is 0.5-2 g / L; (3) fully dissolving aniline in a hydrochloric acid solution with a concentration of 0.05 to 0.1 mol / L to prepare an aniline solution; then dispersing the TA@H-UiO-66 prepared in step (2) in the aniline solution and stirring, and adding ammonium persulfate solution dropwise to react for 0.5 h to 6 h; After centrifugation, the precipitate was collected and dried to obtain TA@H-UiO-66@PANI; The theoretical mass ratio of the aniline, the ammonium persulfate in the ammonium persulfate solution and the TA@H-UiO-66 obtained in step (2) is 1:1-5:0.1-1; the concentration of the aniline solution is 1-10 g / L; (4) preparing a 15-21 wt% PVDF N,N-dimethylformamide solution, adding the TA@H-UiO-66@PANI prepared in step (3) to prepare a modified PVDF casting solution, stirring the modified PVDF casting solution at room temperature overnight to completely disperse it, and then standing to remove bubbles to prepare a uniform polymer solution; using a film scraper to cast the uniform polymer solution on a glass plate at 10-25° C., and then immersing it in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane; The mass ratio of the PVDF to TA@H-UiO-66@PANI is 1:0.025-0.

1.

2. The method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1, characterized in that: In step (4), the thickness of the uniform polymer solution cast on the glass plate is 200 μm.

3. The method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1, characterized in that: In step (4), the modified PVDF casting solution is firstly ultrasonically treated for 0.5-1h and then allowed to stand for 8-12h.

4. The method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1, characterized in that: The acidic solution in step (1) is one or more of hydrochloric acid, sulfuric acid and nitric acid.

5. The method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1, characterized in that: The acidic solution in step (1) is a 0.1 mol / L hydrochloric acid solution.

6. The method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1, characterized in that: The drying in step (1), step (2) and step (3) is vacuum drying at 60°C.

7. The method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1, characterized in that: The reaction temperature of the high-pressure reactor in step (1) is 120° C., and the reaction time is 24 h; the mass ratio of benzoic acid, zirconium chloride and terephthalic acid is 1.832:0.166:0.12; In step (2), the large-pore H-UiO-66 is dispersed in a tannic acid aqueous solution and the reaction time is 1 h; In step (2), the theoretical mass ratio of H-UiO-66 to tannic acid in the tannic acid aqueous solution is 1:1; the concentration of the tannic acid aqueous solution is 1 g / L; In step (3), the concentration of the hydrochloric acid solution is 0.1 mol / L, and the TA@H-UiO-66 is dispersed in the aniline solution, stirred, and ammonium persulfate is added dropwise for a reaction time of 0.5 h; The theoretical mass ratio of the aniline in step (3), the ammonium persulfate in the ammonium persulfate solution and the TA@H-UiO-66 prepared in step (2) is 0.93:2.28:0.085; the concentration of the aniline solution is 5 g / L; The mass ratio of PVDF to TA@H-UiO-66@PANI contained in the modified PVDF casting solution in step (4) is 1:0.025-0.

1.

8. A product of the method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1.

9. The product of the method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 8, characterized in that: The hydrophilic TA@H-UiO-66@PANI / PVDF membrane is a hollow fiber membrane or a flat membrane.

10. Use of the product of the method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 9 as a microporous filter membrane in wastewater treatment.

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