A hydrophilic ta@h-UiO-66@PANI / PVDF membrane, a preparation method and application thereof

Abstract

The application relates to a hydrophilic TA@H-UiO-66@PANI / PVDF membrane and a preparation method and application thereof, the preparation method is characterized in that H-UiO-66 is modified by tannic acid and connected with aniline, aniline is polymerized and deposited on the surface of the membrane to prepare a membrane with high flux and anti-pollution; compared with a traditional PVDF membrane, the hydrophilic TA@H-UiO-66@PANI / PVDF membrane increases transmission channels and improves the flux of the membrane; H-UiO-66 is modified by TA, rich hydrophilic functional groups are introduced, and the super-oleophobicity of polyaniline in water can repel hydrophobic dirt, which helps to improve the anti-pollution of the membrane and prolong the service life of the membrane, and the flux recovery rate is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of membrane separation technology, specifically relating to a hydrophilic membrane separation method.

[0002] TA@H-UiO-66@PANI / PVDF membrane and its preparation method. Background Technology

[0003] In recent years, wastewater treatment to meet specific water quality requirements has become a crucial way to alleviate water scarcity. Membrane technology, due to its advantages of simple operation and high effluent quality, has gradually become a popular separation technology and has been applied in many fields. Polyvinylidene fluoride (PVDF) is one of the commonly used high-molecular organic membrane materials, possessing excellent chemical resistance, high mechanical strength, and good film-forming properties, thus it is widely used in water treatment. However, PVDF membranes suffer from poor hydrophilicity and are prone to fouling; therefore, the development of a high-flux, hydrophilic, and fouling-resistant membrane is of great significance. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a hydrophilic TA@H-UiO-66@PANI / PVDF membrane and its preparation method. The concept lies in using H-UiO-66 material as the main substance for membrane modification to prepare the modified membrane.

[0005] Metal-organic frameworks (MOFs) possess excellent properties such as high porosity, regular pore structure, and numerous adsorption sites. UiO-66 exhibits outstanding hydrothermal and chemical stability, holding promise for breakthroughs in the practical industrial applications of MOF materials. Introducing large-pore H-UiO-66 into membrane research has yielded unexpected results, providing additional transport channels. Tannic acid, rich in phenolic hydroxyl groups, not only provides hydrophilic groups but also typically acts as an anchor, fixing the modified layer to the membrane surface. Conjugated polyaniline influences the water filtration membrane field due to its hydrophilicity and antibacterial properties, simple and inexpensive synthesis methods, heat and acid resistance, and unique doping / dedoping chemistry.

[0006] This invention modifies H-UiO-66 with tannic acid and links it to aniline, then uses aniline polymerization to deposit it onto the membrane surface, thus preparing a membrane with high flux and antifouling properties. To achieve the objectives of this invention, the following technical solution is proposed.

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

[0008] (1) Benzoic acid, zirconium chloride and terephthalic acid were dissolved in N,N-dimethylformamide, and after ultrasonic dissolution, they were transferred to a high-pressure reactor for reaction. The reaction temperature was 100℃~150℃ and the reaction time was 12h~36h. The reaction product was washed and then immersed in an acidic solution for reaction. The reaction solution was centrifuged to obtain the precipitate, and then washed with N,N-dimethylformamide and anhydrous ethanol respectively. After centrifugation, the solid reaction product was taken out and dried to obtain H-UiO-66 with large pore size.

[0009] The mass ratio of 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 obtained in step (1) in an aqueous solution of tannic acid and react for 0.5h to 6h. After centrifugation and drying, TA@H-UiO-66 is obtained.

[0011] The theoretical mass ratio of H-UiO-66 to 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.

[0012] (3) Dissolve aniline completely in a hydrochloric acid solution with a concentration of 0.05-0.1 mol / L to prepare an aniline solution; then disperse the TA@H-UiO-66 prepared in step (2) in the aniline solution and stir, add ammonium persulfate solution dropwise and react for 0.5-6 hours; centrifuge, collect the precipitate, and dry to obtain TA@H-UiO-66@PANI;

[0013] 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 to 5:0.1 to 1; the concentration of the aniline solution is 1 to 10 g / L.

[0014] (4) Prepare a PVDF N,N-dimethylformamide solution with a concentration of 15-21 wt%, add the TA@H-UiO-66@PANI prepared in step (3), prepare a modified PVDF casting solution, stir the modified PVDF casting solution overnight at room temperature to make it completely dispersed, and then let it stand to remove bubbles to prepare a uniform polymer solution; cast the uniform polymer solution onto a glass plate at 10-25℃ using a film doctor blade, and then immerse it in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane;

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

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

[0017] Furthermore, in step (4), the modified PVDF casting solution is first ultrasonically treated for 0.5-1h, and then allowed to stand for 8-12h. The purpose of ultrasonic treatment is to remove air bubbles from the solution more quickly. There is no power requirement. Compared with no ultrasonic treatment, the standing time can be shortened by ultrasonic treatment.

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

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

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

[0021] In step (2), the large-pore size H-UiO-66 is dispersed in an aqueous solution of tannic acid and reacted for 1 hour.

[0022] The theoretical mass ratio of H-UiO-66 to tannic acid in the tannic acid aqueous solution 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 ammonium persulfate added dropwise is 0.5 h.

[0024] The theoretical mass ratio of aniline in step (3), ammonium persulfate in the ammonium persulfate solution, and TA@H-UiO-66 obtained in step (2) is 0.93:2.28:0.085; the concentration of the aniline solution is 5 g / L.

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

[0026] Secondly, the present invention proposes a product of the above-mentioned 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 sheet membrane.

[0029] Thirdly, the product of the method for preparing the hydrophilic TA@H-UiO-66@PANI / PVDF membrane proposed in this invention can be used as a microporous filter membrane in wastewater treatment.

[0030] The beneficial effects of this invention are as follows: introducing H-UiO-66 onto the surface of the PVDF membrane increases the transport channels and improves the membrane flux; using TA to modify H-UiO-66 introduces abundant hydrophilic functional groups, and the superoleophobicity of polyaniline in water can repel hydrophobic fouling, which helps to improve the membrane's antifouling properties and extend its service life, as reflected in a significantly improved flux recovery rate. Detailed Implementation

[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 or implementations that do not depart from the content and scope of the present invention should be included within the technical scope of the present invention.

[0032] In the examples below, the membrane performance is evaluated using two parameters: pure water flux (J) and flux recovery rate (FRR). Water flux refers to the volume of water passing through a unit membrane area per unit time under unit pressure. Typically, ultrafiltration membrane tests are conducted under the same water pressure conditions. The flux is calculated using the following formula:

[0033]

[0034] Among them, J W Pure water flux (L / m 2 ·h), V w Let A be the volume of pure water filtered (L) and A be the effective filtration area (m²). 2 ), Δt is the time taken (h), J w1 The initial water flux (L / m) during the filtration of pure water 2 ·h), J w2 The water flux (L / m³) of filtered pure water after filtering bovine serum albumin solution and rinsing with water. 2 •h). Flux recovery rate (FRR) refers to the percentage of membrane flux that recovers to its initial flux during membrane separation. It reflects the membrane's ability to recover after fouling and is one of the important indicators for measuring membrane performance. A higher FRR value indicates a better flux recovery rate. The definition and calculation method of flux recovery rate are as follows:

[0035]

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

[0037] Rate

[0038] Example 1

[0039] (1) 3.4 g of PVDF polymer powder was dissolved in 17.58 ml of N,N-dimethylformamide solvent to prepare a 17% (w / w) PVDF solution. The solution was stirred overnight at room temperature to ensure complete dispersion. Before use, it was sonicated for half an hour and allowed to stand for 12 hours to remove air bubbles. Then, a uniform polymer solution with a thickness of 200 μm was cast onto a glass plate at room temperature using a membrane doctor blade. The glass plate was then immersed in water for solvent exchange for 1 day to prepare a PVDF membrane. The pure water flux of the original membrane was measured under the same transmembrane pressure (0.1 MPa). After the ultrafiltration membrane was pre-pressed in pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 .

[0040] First, the initial flux was obtained by filtering pure water for 30 minutes (6 sets of data were measured at an average of 5 minutes each). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (6 sets of data were measured at an average of 10 minutes each). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered with pure water again for 30 minutes (6 sets of data were measured at an average of 5 minutes each). The above steps were repeated for the second dynamic filtration cycle.

[0041] The prepared PVDF membrane exhibits a pure water flux of 115 L / m³ at room temperature and 0.1 MPa. 2 The flux recovery rate was 52.17% (see Table 1 for details).

[0042] Example 2

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

[0044] The pure water flux of the modified membrane was measured at a transmembrane pressure of 0.1 MPa. After the ultrafiltration membrane was pre-pressurized with pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 .

[0045] Then, the modified membrane was subjected to two consecutive dynamic filtration cycles at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by filtering pure water for 30 minutes (averaging six sets of data every five minutes). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (averaging six sets of data every ten minutes). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered again with pure water for 30 minutes (averaging six sets of data every five minutes) to complete the first dynamic filtration cycle. The above steps were repeated for the second dynamic filtration cycle.

[0046] The prepared TA@H-UiO-66@PANI / PVDF membrane exhibits a pure water flux of 612 L / m³ at room temperature and 0.1 MPa. 2 •h, flux recovery rate was 76.58%, see Table 1 for details.

[0047] Example 3

[0048] (1) Dissolve 1.832g of benzoic acid in 20mL of DMF. After complete dissolution, add 0.166g of terephthalic acid and 0.12g of zirconium chloride and dissolve. Transfer the dissolved solution to a reaction vessel and react at 120℃ for 24h. After washing twice with DMF, disperse in 0.1mol / L hydrochloric acid solution for 30min. Centrifuge the reaction solution to collect the precipitate, and wash with DMF and ethanol respectively by centrifugation. Repeat the washing three times to obtain large-pore H-UiO-66. (2) Dissolve 0.1g of TA in 100mL of water, adjust the pH to 8.5, add 0.1g of H-UiO-66, stir for 1h, and centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93g of aniline in 200mL of 0.1mol / L HCl solution, add 0.085g of TA@H-UiO-66 and stir to disperse. Add 2.28g of ammonium persulfate to 10mL of 0.1mol / L HCl solution and dissolve. Add the solution dropwise to the aniline solution containing TA@H-UiO-66 and react for 0.5h. Centrifuge and collect the precipitate to obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4g of PVDF polymer powder in 17.58ml of N,N-dimethylformamide solvent to obtain a 17wt% N,N-dimethylformamide solution of PVDF. Add 0.136g of TA@H-UiO-66@PANI to prepare a modified PVDF casting solution. Stir the modified PVDF casting solution overnight at room temperature to ensure complete dispersion. Before use, sonicate for half an hour and let stand for 12h to remove air bubbles. Then, a uniform polymer solution with a thickness of 200 μm was cast onto a glass plate at room temperature using a membrane doctor blade. The glass plate was then immersed in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane. The pure water flux of the modified membrane was measured under the same transmembrane pressure (0.1 MPa). After pre-pressuring the ultrafiltration membrane in pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 .

[0049] Then, the modified membrane was subjected to two consecutive dynamic filtration cycles at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by filtering pure water for 30 minutes (averaging six sets of data every five minutes). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (averaging six sets of data every ten minutes). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered with pure water again for 30 minutes (averaging six sets of data every five minutes) to complete 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 exhibits a pure water flux of 619 L / m³ at room temperature and 0.1 MPa. 2 • h, flux recovery rate was 80.43%, see 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. Transfer the dissolved solution to a reaction vessel and react at 120 °C for 24 h. After washing twice with DMF, disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to collect the precipitate, 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, add 0.1 g of H-UiO-66, stir for 1 h, and centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93g of aniline in 200mL of 0.1mol / L HCl solution, add 0.085g of TA@H-UiO-66 and stir to disperse. Add 2.28g of ammonium persulfate to 10mL of 0.1mol / L HCl solution and dissolve. Add the solution dropwise to the aniline solution containing TA@H-UiO-66 and react for 0.5h. Centrifuge and wash, collect the precipitate, and obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4g of PVDF polymer powder in 17.58ml of N,N-dimethylformamide solvent to obtain a 17wt% N,N-dimethylformamide solution of PVDF. Add 0.17g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution at room temperature overnight to ensure complete dispersion. Then, sonicate for half an hour before use and let stand for 12h to remove air bubbles. Then, a uniform polymer solution with a thickness of 200 μm was cast onto a glass plate at room temperature using a membrane doctor blade. The glass plate was then immersed in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane. The pure water flux of the modified membrane was measured under the same transmembrane pressure (0.1 MPa). After pre-pressuring the ultrafiltration membrane in pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 .

[0053] Then, the modified membrane was subjected to two consecutive dynamic filtration cycles at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by filtering pure water for 30 minutes (averaging six sets of data every five minutes). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (averaging six sets of data every ten minutes). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered with pure water again for 30 minutes (averaging six sets of data every five minutes) to complete the first dynamic filtration cycle. The above steps were repeated for the second dynamic filtration cycle.

[0054] The prepared TA@H-UiO-66@PANI / PVDF membrane exhibits a pure water flux of 624 L / m³ at room temperature and 0.1 MPa. 2 •h, flux recovery rate was 82.55%, see Table 1 for details.

[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 vessel and react at 120 °C for 24 h. After washing twice with DMF, disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to collect the precipitate, 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, add 0.1 g of H-UiO-66, stir for 1 h, and centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93g of aniline in 200mL of 0.1mol / L HCl solution, add 0.085g of TA@H-UiO-66 and stir to disperse. Add 2.28g of ammonium persulfate to 10mL of 0.1mol / L HCl solution and dissolve. Add the solution dropwise to the aniline solution containing TA@H-UiO-66 and react for 0.5h. Centrifuge and wash, collect the precipitate, and obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4g of PVDF polymer powder in 17.58ml of N,N-dimethylformamide solvent to obtain a 17wt% N,N-dimethylformamide solution of PVDF. Add 0.204g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution at room temperature overnight to ensure complete dispersion. Then, sonicate for half an hour before use and let stand for 12h to remove bubbles. Then, a uniform polymer solution with a thickness of 200 μm was cast onto a glass plate at room temperature using a membrane doctor blade. The glass plate was then immersed in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane. The pure water flux of the modified membrane was measured under the same transmembrane pressure (0.1 MPa). After pre-pressuring the ultrafiltration membrane in pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 The test lasted 120 minutes, with measurements taken every ten minutes to obtain the average flux, in order to minimize experimental error.

[0057] Then, the modified membrane was subjected to two consecutive dynamic filtration cycles at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by filtering pure water for 30 minutes (averaging six sets of data every five minutes). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (averaging six sets of data every ten minutes). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered again with pure water for 30 minutes (averaging six sets of data every five minutes), completing the first dynamic filtration cycle. The above steps were repeated for the second dynamic filtration cycle.

[0058] The prepared TA@H-UiO-66@PANI / PVDF membrane exhibits a pure water flux of 498 L / m³ at room temperature and 0.1 MPa. 2 The flux recovery rate was 81.49% (see 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. Transfer the dissolved solution to a reaction vessel and react at 120 °C for 24 h. After washing twice with DMF, disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to collect the precipitate, 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, add 0.1 g of H-UiO-66, stir for 1 h, and centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93g of aniline in 200mL of 0.1mol / L HCl solution, add 0.085g of TA@H-UiO-66 and stir to disperse. Add 2.28g of ammonium persulfate to 10mL of 0.1mol / L HCl solution and dissolve. Add the solution dropwise to the aniline solution containing TA@H-UiO-66 and react for 0.5h. Centrifuge and wash, collect the precipitate, and obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4g of PVDF polymer powder in 17.58ml of N,N-dimethylformamide solvent to obtain a 17wt% N,N-dimethylformamide solution of PVDF. Add 0.204g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution at room temperature overnight to ensure complete dispersion. Then, sonicate for half an hour before use and let stand for 12h to remove bubbles. Then, a uniform polymer solution with a thickness of 200 μm was cast onto a glass plate at room temperature using a membrane doctor blade. The glass plate was then immersed in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane. The pure water flux of the modified membrane was measured under the same transmembrane pressure (0.1 MPa). After pre-pressuring the ultrafiltration membrane in pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 The test lasted 120 minutes, with measurements taken every ten minutes to obtain the average flux, in order to minimize experimental error.

[0061] Then, the modified membrane was subjected to two consecutive dynamic filtration cycles at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by filtering pure water for 30 minutes (averaging six sets of data every five minutes). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (averaging six sets of data every ten minutes). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered with pure water again for 30 minutes (averaging six sets of data every five minutes) to complete the first dynamic filtration cycle. The above steps were repeated for the second dynamic filtration cycle.

[0062] The prepared TA@H-UiO-66@PANI / PVDF membrane exhibits a pure water flux of 498 L / m³ at room temperature and 0.1 MPa. 2 The flux recovery rate was 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. Transfer the dissolved solution to a reaction vessel and react at 120 °C for 24 h. After washing twice with DMF, disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to collect the precipitate, 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, add 0.1 g of H-UiO-66, stir for 1 h, and centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93g of aniline in 200mL of 0.1mol / L HCl solution, add 0.085g of TA@H-UiO-66 and stir to disperse. Add 2.28g of ammonium persulfate to 10mL of 0.1mol / L HCl solution and dissolve. Add the solution dropwise to the aniline solution containing TA@H-UiO-66 and react for 0.5h. Centrifuge and wash, collect the precipitate, and obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4g of PVDF polymer powder in 17.58ml of N,N-dimethylformamide solvent to obtain a 17wt% N,N-dimethylformamide solution of PVDF. Add 0.255g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution at room temperature overnight to ensure complete dispersion. Then, sonicate for half an hour before use and let stand for 12h to remove bubbles. Then, a uniform polymer solution with a thickness of 200 μm was cast onto a glass plate at room temperature using a membrane doctor blade. The glass plate was then immersed in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane. The pure water flux of the modified membrane was measured under the same transmembrane pressure (0.1 MPa). After pre-pressuring the ultrafiltration membrane in pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 The test lasted 120 minutes, with measurements taken every ten minutes to obtain the average flux, in order to minimize experimental error.

[0065] Then, the modified membrane was subjected to two consecutive dynamic filtration cycles at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by filtering pure water for 30 minutes (averaging six sets of data every five minutes). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (averaging six sets of data every ten minutes). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered again with pure water for 30 minutes (averaging six sets of data every five minutes), completing the first dynamic filtration cycle. The above steps were repeated for the second dynamic filtration cycle.

[0066] The prepared TA@H-UiO-66@PANI / PVDF membrane exhibits a pure water flux of 322 L / m³ at room temperature and 0.1 MPa. 2 The flux recovery rate was 81.79% (see 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. Transfer the dissolved solution to a reaction vessel and react at 120 °C for 24 h. After washing twice with DMF, disperse in 0.1 mol / L hydrochloric acid solution for 30 min. Centrifuge the reaction solution to collect the precipitate, 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, add 0.1 g of H-UiO-66, stir for 1 h, and centrifuge to obtain TA@H-UiO-66. (3) Dissolve 0.93g of aniline in 200mL of 0.1mol / L HCl solution, add 0.085g of TA@H-UiO-66 and stir to disperse. Add 2.28g of ammonium persulfate to 10mL of 0.1mol / L HCl solution and dissolve. Add the solution dropwise to the aniline solution containing TA@H-UiO-66 and react for 0.5h. Centrifuge and wash, collect the precipitate, and obtain TA@H-UiO-66@PANI. (4) Dissolve 3.4g of PVDF polymer powder in 17.58ml of N,N-dimethylformamide solvent to obtain a 17wt% N,N-dimethylformamide solution of PVDF. Add 0.34g of TA@H-UiO-66@PANI to prepare a modified casting solution. Stir the modified casting solution at room temperature overnight to ensure complete dispersion. Then, sonicate for half an hour before use and let stand for 12h to remove air bubbles. Then, a uniform polymer solution with a thickness of 200 μm was cast onto a glass plate at room temperature using a film doctor blade, and the glass plate was then immersed in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane.

[0069] The pure water flux of the modified membrane was measured under the same transmembrane pressure (0.1 MPa). After the ultrafiltration membrane was pre-pressurized in pure water at 0.1 MPa for 30 min to obtain a stable flux, the effective membrane area was approximately 9 cm². 2 .

[0070] Then, the modified membrane was subjected to two consecutive dynamic filtration cycles at the same transmembrane pressure of 0.1 MPa. First, the initial flux was obtained by filtering pure water for 30 minutes (averaging six sets of data every five minutes). Then, the flux was measured for 60 minutes using a 1 g / L BSA solution instead of pure water (averaging six sets of data every ten minutes). Next, the membrane surface was thoroughly rinsed with deionized water for 30 minutes to remove reversibly adsorbed proteins. Finally, the rinsed membrane was filtered again with pure water for 30 minutes (averaging six sets of data every five minutes), completing the first dynamic filtration cycle. The above steps were repeated for the second dynamic filtration cycle.

[0071] The prepared TA@H-UiO-66@PANI / PVDF membrane exhibits a pure water flux of 185 L / m³ at room temperature and 0.1 MPa. 2 •h, flux recovery rate was 80.13%, see Table 1 for details.

[0072] Table 1: Membrane Performance Testing

[0073]

[0074] At an operating pressure of 0.1 MPa, the membrane pure water flux in Example 1 was 115 L / m³. 2 •h. The membrane flux in Example 4 reached 624 L / m. 2 However, as the concentration of TA@H-UiO-66@PANI material increased, the pure water flux of the ultrafiltration membrane first increased and then decreased. In Example 7, the pure water flux of the membrane was only 185 L / m³. 2 • h. During dynamic antifouling performance testing, the membrane's antifouling performance was studied using multiple cycles of filtration with a 0.1 g / L BSA aqueous solution. The flux recovery rate of the membrane in Example 4 reached 82.55%. This indicates that the modified membrane significantly improved flux and also enhanced antifouling performance, with the best performance achieved when the TA@H-UiO-66@PANI material was added at the amount found in Example 4.

Claims

1. A method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane, comprising the following steps: (1) Benzoic acid, zirconium chloride and terephthalic acid were dissolved in N,N-dimethylformamide, and after ultrasonic dissolution, they were transferred to a high-pressure reactor for reaction. The reaction temperature was 100℃~150℃ and the reaction time was 12h~36h. The reaction product was washed and then immersed in an acidic solution for reaction. The reaction solution was centrifuged to obtain the precipitate, which was then washed with N,N-dimethylformamide and anhydrous ethanol, centrifuged, and the solid reaction product was taken out and dried to obtain H-UiO-66 with large pore size. The mass ratio of benzoic acid, zirconium chloride, and terephthalic acid is 1.7~1.9:0.15~0.17:0.1~0.

12. (2) Disperse the large-pore H-UiO-66 prepared in step (1) in an aqueous solution of tannic acid and react for 0.5 h to 6 h. After centrifugation and drying, obtain TA@ H-UiO-66. The mass ratio of H-UiO-66 to 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) Prepare an aniline solution by fully dissolving aniline in a hydrochloric acid solution with a concentration of 0.05~0.1 mol / L; The TA@ H-UiO-66 prepared in step (2) is then dispersed in the aniline solution and stirred. Ammonium persulfate solution is added dropwise and reacted for 0.5 h to 6 h. The precipitate is collected by centrifugation and dried to obtain TA@ H-UiO-66@PANI. The mass ratio of aniline, ammonium persulfate in the ammonium persulfate solution, and 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) Prepare a PVDF N,N-dimethylformamide solution with a concentration of 15~21 wt%, add the TA@ H-UiO-66@PANI prepared in step (3), prepare a modified PVDF casting solution, stir the modified PVDF casting solution at room temperature overnight to make it completely dispersed, and then let it stand to remove bubbles to make a uniform polymer solution; cast the uniform polymer solution onto a glass plate at 10-25℃ using a film doctor blade, and then immerse it in water for solvent exchange for 1 day to prepare a TA@H-UiO-66@PANI / PVDF membrane; The mass ratio of PVDF to TA@H-UiO-66@PANI is 1:0.025~0.1; In step (4), the thickness of the uniform polymer solution cast on the glass plate is 200 μm.

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 modified PVDF casting solution is first ultrasonically treated for 0.5-1h, and then left to stand for 8-12h.

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

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

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

6. A 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℃ and the reaction time is 24h; the mass ratio of benzoic acid, zirconium chloride and terephthalic acid is 1.832:0.166:0.12; In step (2), the large-pore size H-UiO-66 is dispersed in an aqueous solution of tannic acid and reacted for 1 hour. In step (2), the 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 reaction time for TA@ H-UiO-66 dispersed in the aniline solution and ammonium persulfate added dropwise is 0.5 h. The mass ratio of aniline in step (3), ammonium persulfate in the ammonium persulfate solution, and TA@H-UiO-66 obtained in step (2) is 0.93:2.28:0.085; the concentration of the aniline solution is 5 g / L. The modified PVDF casting solution described in step (4) contains PVDF in a mass ratio of 1:0.025~0.1 to TA@H-UiO-66@PANI.

7. The membrane prepared by the method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 1.

8. The membrane prepared by the method for preparing a hydrophilic TA@H-UiO-66@PANI / PVDF membrane according to claim 7 is used as a microporous filter membrane in wastewater treatment.

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