Water treatment membrane material compound and preparation method thereof

Abstract

The invention relates to the field of water treatment membrane material preparation, in particular to a water treatment membrane material compound and a preparation method thereof. According to the water treatment membrane material compound provided by the invention, the polymer and the MOFs are effectively polymerized together, so that not only are the excellent selectivity and adsorption performance of the MOFs material reserved, but also the defects of poor mechanical strength and poor stability when the MOFs are independently applied are overcome. The newly synthesized water treatment membrane material compound has very high selectivity, high water flux, good mechanical strength and durability, can efficiently remove harmful metal ions and organic pollutants in water, remarkably improves the water treatment efficiency, and has remarkable environmental protection benefits.

Description

Technical Field

[0001] The invention relates to the field of water treatment membrane material preparation, and in particular to a water treatment membrane material composite and a preparation method thereof. Background Art

[0002] As the global industrialization process continues to accelerate, water pollution issues are becoming increasingly prominent, and water quality deterioration has become a global environmental issue. In this context, the presence of harmful metal ions and organic pollutants in water bodies not only poses a serious threat to human drinking water safety, but also causes irreversible damage to aquatic ecosystems. These pollutants are highly stable and toxic, and can accumulate and amplify their toxic effects through the food chain, thereby affecting the balance and health of the entire ecosystem.

[0003] For the treatment of such complex pollutants, traditional water treatment methods, such as physical adsorption, precipitation and chemical degradation, can remove some pollutants to a certain extent, but they have exposed many limitations in practical applications. For example, physical adsorption often has problems such as limited adsorption capacity and low treatment efficiency; precipitation may cause secondary pollution due to the generation of difficult-to-treat sludge; chemical degradation may have a negative impact on the environment due to the use of a large amount of chemical reagents, and has poor selectivity, making it difficult to achieve efficient removal of specific pollutants.

[0004] In view of the various shortcomings of traditional water treatment methods, researchers are constantly committed to exploring new water treatment technologies that are more efficient and environmentally friendly. In recent years, membrane separation technology has shown great application potential in the field of water treatment due to its significant characteristics such as high efficiency separation, low energy consumption, and environmental friendliness. This technology can selectively separate and remove pollutants of different sizes, charges, and properties in water bodies through specific membrane materials, thereby effectively improving the efficiency and selectivity of water treatment, and providing new ideas and ways to solve the current severe water pollution problem.

[0005] Therefore, membrane separation technology has gradually become an important research direction in the field of water treatment, and it is very promising to invent a water treatment membrane material composite. Summary of the invention

[0006] In view of the above-mentioned existing technical problems, the present invention aims to provide a water treatment membrane material composite and a preparation method thereof. The water treatment membrane material composite prepared by this method effectively polymerizes the polymer and MOFs together, so that the water treatment membrane material composite has high selectivity and high water flux, good mechanical strength and durability, can efficiently remove harmful metal ions and organic pollutants in water, significantly improve water treatment efficiency, and has significant environmental benefits.

[0007] The present invention discloses a method for preparing a water treatment membrane material composite, comprising the following preparation steps:

[0008] S1 Composite membrane solution synthesis: dissolving polyethersulfone in a solvent, stirring and heating until the polyethersulfone is completely dissolved to form a polymer solution; dissolving the metal organic framework material in ammonia water to form a gel; then adding the metal organic framework material gel to the above polymer solution, stirring and mixing to obtain a composite membrane solution;

[0009] S2 Preparation of water treatment membrane material composite: Add the composite membrane liquid obtained in step S1 to the electrospinning apparatus, set the voltage, injection distance and injection flow rate of the electrospinning apparatus, and then spray the composite membrane liquid to form nanofibers, and guide them to the collecting plate through the electric field to form a composite membrane; then dry and heat-treat the composite membrane to obtain a water treatment membrane material composite after curing.

[0010] Preferably, in the S1 composite membrane solution synthesis step, the solvent is N-methylpyrrolidone.

[0011] Preferably, in the S1 composite membrane solution synthesis step, the mass concentration of the polymer solution is 1 to 1.5 g / L.

[0012] Preferably, in the step S1 of synthesizing the composite membrane solution, the metal organic framework material is a mesh metal-organic framework material.

[0013] Preferably, in the S1 composite membrane solution synthesis step, the mass fraction of the metal organic framework material in the gel is 15-30%.

[0014] Preferably, in the S1 composite membrane solution synthesis step, the temperature of the stirring, heating and dissolving is 60-80°C.

[0015] Preferably, in the S1 composite membrane liquid synthesis step, the stirring and mixing method for uniformly mixing to obtain the composite membrane liquid is ultrasonic mixing, and the ultrasonic frequency is 20 to 40 Hz.

[0016] Preferably, in the S2 water treatment membrane material composite preparation step, the voltage of the electrospinning apparatus is set to 15-25 kV.

[0017] Preferably, in the S2 water treatment membrane material composite preparation step, the spraying distance is 10 to 20 cm, and the spraying flow rate is 1 to 2 ml / min.

[0018] A water treatment membrane material composite is prepared by any one of the above-mentioned methods for preparing a water treatment membrane material composite.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a water treatment membrane material composite and a preparation method thereof. Metal organic framework materials (MOFs) are embedded in a polymer matrix by a chemical synthesis method to optimize the pore structure of the composite membrane, which can effectively improve the selectivity and water flux of the membrane. The polymer and MOFs composite of the present invention not only retains the excellent selectivity and adsorption performance of the MOFs material, but also overcomes the defects of poor mechanical strength and poor stability when MOFs are used alone. The pore structure of MOFs in the water treatment membrane material composite prepared by the preparation method provided by the present invention can be adjusted to adapt to the removal of specific pollutants, has high selectivity, and can effectively remove harmful metal ions (such as lead, mercury, chromium, etc.) and organic pollutants in water. Since the embedding of MOFs optimizes the pore structure of the composite, a higher water flux is guaranteed to meet the water treatment needs in industrial applications. The introduction of the polymer matrix improves the mechanical strength and durability of the composite membrane and extends the service life of the membrane. DETAILED DESCRIPTION

[0021] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0022] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0023] Embodiment 1: A method for preparing a water treatment membrane material composite comprises the following steps:

[0024] S1 Composite membrane liquid synthesis: polyethersulfone is dissolved in N-methylpyrrolidone, and the mixture is stirred and heated to 60°C to completely dissolve the polyethersulfone to form a polymer solution with a mass concentration of 1 g / L; metal organic framework materials (MOFs) are dissolved in ammonia water to form a gel with a mass fraction of 15%; the metal organic framework material gel is then added to the above polymer solution, and the composite membrane liquid is obtained by uniformly mixing the mixture by ultrasonic stirring, wherein the frequency of the ultrasonic wave is 20 Hz.

[0025] S2 Preparation of water treatment membrane material composite: Add the composite membrane liquid obtained in step S1 to an electrospinning apparatus, set the voltage of the electrospinning apparatus to 15 kV, the spray distance to 10 cm, and the spray flow rate to 1 ml / min, then spray the composite membrane liquid to form nanofibers, and guide them to a collecting plate through an electric field to form a composite membrane; then dry and heat-treat the composite membrane to obtain a water treatment membrane material composite after curing.

[0026] Embodiment 2: A method for preparing a water treatment membrane material composite comprises the following steps:

[0027] S1 Composite membrane liquid synthesis: polyethersulfone was dissolved in N-methylpyrrolidone, and the mixture was stirred and heated to 65°C to completely dissolve the polyethersulfone to form a polymer solution with a mass concentration of 1.1 g / L; metal organic framework materials (MOFs) were dissolved in ammonia water to form a gel with a mass fraction of 17%; the metal organic framework material gel was then added to the above polymer solution, and the composite membrane liquid was obtained by uniformly mixing the mixture by ultrasonic stirring, wherein the frequency of the ultrasonic wave was 25 Hz.

[0028] S2 Preparation of water treatment membrane material composite: Add the composite membrane liquid obtained in step S1 to an electrospinning apparatus, set the voltage of the electrospinning apparatus to 17 kV, the spray distance to 12 cm, and the spray flow rate to 1.2 ml / min, then spray the composite membrane liquid to form nanofibers, and guide them to a collecting plate through an electric field to form a composite membrane; then dry and heat-treat the composite membrane to obtain a water treatment membrane material composite after curing.

[0029] Embodiment 3: A method for preparing a water treatment membrane material composite comprises the following steps:

[0030] S1 Composite membrane liquid synthesis: polyethersulfone is dissolved in N-methylpyrrolidone, and the mixture is stirred and heated to 70°C to completely dissolve the polyethersulfone to form a polymer solution with a mass concentration of 1.2 g / L; metal organic framework materials (MOFs) are dissolved in ammonia water to form a gel with a mass fraction of 20%; the metal organic framework material gel is then added to the above polymer solution, and the composite membrane liquid is obtained by uniformly mixing the mixture by ultrasonic stirring, wherein the frequency of the ultrasonic wave is 30 Hz.

[0031] S2 Preparation of water treatment membrane material composite: Add the composite membrane liquid obtained in step S1 to an electrospinning apparatus, set the voltage of the electrospinning apparatus to 20 kV, the spray distance to 15 cm, and the spray flow rate to 1.5 ml / min, then spray the composite membrane liquid to form nanofibers, and guide them to a collecting plate through an electric field to form a composite membrane; then dry and heat-treat the composite membrane to obtain a water treatment membrane material composite after curing.

[0032] Embodiment 4: A method for preparing a water treatment membrane material composite comprises the following steps:

[0033] S1 Composite membrane liquid synthesis: polyethersulfone is dissolved in N-methylpyrrolidone, and the mixture is stirred and heated to 75°C to completely dissolve the polyethersulfone to form a polymer solution with a mass concentration of 1.3 g / L; metal organic framework materials (MOFs) are dissolved in ammonia water to form a gel with a mass fraction of 25%; the metal organic framework material gel is then added to the above polymer solution, and the composite membrane liquid is obtained by uniformly mixing the mixture by ultrasonic stirring, wherein the frequency of the ultrasonic wave is 35 Hz.

[0034] S2 Preparation of water treatment membrane material composite: Add the composite membrane liquid obtained in step S1 to an electrospinning apparatus, set the voltage of the electrospinning apparatus to 22 kV, the spray distance to 17 cm, and the spray flow rate to 1.7 ml / min, then spray the composite membrane liquid to form nanofibers, and guide them to a collecting plate through an electric field to form a composite membrane; then dry and heat-treat the composite membrane to obtain a water treatment membrane material composite after curing.

[0035] Embodiment 5: A method for preparing a water treatment membrane material composite comprises the following steps:

[0036] S1 Composite membrane liquid synthesis: polyethersulfone is dissolved in N-methylpyrrolidone, and the mixture is stirred and heated to 80°C to completely dissolve the polyethersulfone to form a polymer solution with a mass concentration of 1.5 g / L; metal organic framework materials (MOFs) are dissolved in ammonia water to form a gel with a mass fraction of 30%; the metal organic framework material gel is then added to the above polymer solution, and the composite membrane liquid is obtained by uniformly mixing the mixture by ultrasonic stirring, wherein the frequency of the ultrasonic wave is 40 Hz.

[0037] S2 Preparation of water treatment membrane material composite: Add the composite membrane liquid obtained in step S1 to an electrospinning apparatus, set the voltage of the electrospinning apparatus to 25 kV, the spray distance to 20 cm, and the spray flow rate to 2 ml / min, then spray the composite membrane liquid to form nanofibers, and guide them to a collecting plate through an electric field to form a composite membrane; then dry and heat-treat the composite membrane to obtain a water treatment membrane material composite after curing.

[0038] Embodiment 6: A method for preparing a water treatment membrane material composite comprises the following steps:

[0039] S1 polymer solution synthesis: polyethersulfone was dissolved in N-methylpyrrolidone, and the mixture was stirred and heated to 75°C to completely dissolve the polyethersulfone to form a polymer solution with a mass concentration of 1.3 g / L;

[0040] S2 Preparation of water treatment membrane material composite: Add the polymer solution obtained in step S1 to the electrospinning apparatus, set the voltage of the electrospinning apparatus to 22 kV, the spray distance to 17 cm, and the spray flow rate to 1.7 ml / min, then spray the polymer solution to form nanofibers, and guide them to the collecting plate through the electric field, and then dry and heat treat and solidify to obtain the water treatment membrane material.

[0041] Embodiment 7: A method for preparing a water treatment membrane material composite comprises the following steps:

[0042] S1 Synthesis of metal organic framework material gel: The metal organic framework material (MOFs) was dissolved in ammonia water and mixed evenly by ultrasonic stirring to form a gel with a mass fraction of 25%; the frequency of the ultrasonic wave was 35 Hz.

[0043] S2 Preparation of water treatment membrane material composite: Add the metal organic framework material gel obtained in step S1 to the electrospinning instrument, set the voltage of the electrospinning instrument to 22 kV, the spray distance to 17 cm, and the spray flow rate to 1.7 ml / min, then spray the metal organic framework material gel to form nanofibers, and guide them to the collection plate through an electric field, and then dry and heat treat to obtain the water treatment membrane material after curing.

[0044] The water treatment membrane material composites prepared in Examples 1 to 5 and the water treatment membrane materials prepared in Examples 6 to 7 were subjected to performance tests, and the various test experiments are as follows:

[0045] (1) Selectivity: Select common water pollutant heavy metal ions (Pb 2+ , Cu 2+ ) and organic matter (dyes, acid orange). The water treatment membrane material composite is immersed in an aqueous solution containing a known concentration of pollutants. The pollutant concentration in the original aqueous solution and the aqueous solution after membrane filtration is measured (using ICP-OES, UV-Vis, etc.). The removal rate is calculated (removal rate = (initial concentration - concentration after filtration) / initial concentration × 100%).

[0046] (2) Mechanical strength: Use a universal material testing machine to test the tensile strength and elongation at break of the water treatment membrane. Tensile strength: The maximum force that the membrane withstands when it breaks divided by the cross-sectional area of ​​the membrane, usually in MPa. Elongation at break: The ratio of the extended length of the membrane when it breaks to the initial length, in percentage (%).

[0047] (3) Durability: The membrane was immersed in solutions with different pH values ​​(e.g., pH 4, 7, 10) and temperature conditions. After a time interval (2 weeks), the changes in the membrane's selectivity, mechanical strength, and water flux were tested.

[0048] Stability: The performance degradation of the membrane was observed by conducting experiments on the membrane for a long time (one month).

[0049] (4) Water flux test: Pure water is passed through the membrane and the amount of water passing through per unit time is recorded.

[0050] The experimental data records of (1) to (4) are shown in the following table:

[0051]

[0052]

[0053] From the experimental data in the above table, it can be seen that the removal rates of Examples 4 and 5 are the highest, reaching 95% and 94% respectively; the tensile strength and elongation at break are relatively high; they have good durability under different pH conditions; and the water flux is relatively high, reaching 390L / m 2 h and 375L / m 2 ·h. The removal rates of Examples 1 to 3 are relatively low, but all above 90%; the tensile strength and elongation at break are relatively poor, but all above 12MPa and 25%; the water flux is also above 300L / m 2 ·h or more; durability and stability are also good. The removal rate, tensile strength, elongation at break, water flux, durability and stability of Example 6 and Example 7 are all very poor. Therefore, Example 4 and Example 5 perform best in all performance indicators, with higher selectivity, mechanical strength, water flux and better durability and stability. The performance of Examples 1 to 3 is slightly inferior to that of Examples 4 to 5 in all aspects. The performance of Examples 6 and Example 7 is relatively poor in all aspects.

[0054] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A method for preparing a water treatment membrane material composite, characterized in that: The following steps are involved: S1 Composite membrane solution synthesis: dissolving polyethersulfone in a solvent, stirring and heating until the polyethersulfone is completely dissolved to form a polymer solution; dissolving the metal organic framework material in ammonia water to form a gel; then adding the metal organic framework material gel to the above polymer solution, stirring and mixing to obtain a composite membrane solution; S2 Preparation of water treatment membrane material composite: Add the composite membrane liquid obtained in step S1 to the electrospinning apparatus, set the voltage, injection distance and injection flow rate of the electrospinning apparatus, and then spray the composite membrane liquid to form nanofibers, and guide them to the collecting plate through the electric field to form a composite membrane; then dry and heat-treat the composite membrane to obtain a water treatment membrane material composite after curing.

2. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the S1 composite membrane solution synthesis step, the solvent is N-methylpyrrolidone.

3. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the S1 composite membrane solution synthesis step, the mass concentration of the polymer solution is 1 to 1.5 g / L.

4. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the S1 composite membrane solution synthesis step, the metal organic framework material is a mesh metal-organic framework material.

5. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the S1 composite membrane solution synthesis step, the mass fraction of the metal organic framework material in the gel is 15-30%.

6. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the S1 composite membrane solution synthesis step, the temperature for stirring, heating and dissolving is 60-80°C.

7. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the step S1 of synthesizing the composite membrane liquid, the stirring and mixing method for uniformly mixing the composite membrane liquid is ultrasonic mixing, and the ultrasonic frequency is 20 to 40 Hz.

8. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the S2 water treatment membrane material composite preparation step, the voltage of the electrospinning apparatus was set to 15–25 kV.

9. The method for preparing a water treatment membrane material composite according to claim 1, characterized in that: In the step of preparing the S2 water treatment membrane material composite, the spraying distance is 10 to 20 cm, and the spraying flow rate is 1 to 2 ml / min.

10. The water treatment membrane material composite prepared by the method for preparing a water treatment membrane material composite according to any one of claims 1 to 9.

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