Nano mixed matrix nanofiltration membrane with uniformly dispersed sulfonated hydrophenol and preparation method of nano mixed matrix nanofiltration membrane

Abstract

The invention provides a nano mixed matrix nanofiltration membrane with uniformly dispersed sulfonated hydrophenol and a preparation method of the nano mixed matrix nanofiltration membrane, and relates to the field of nanofiltration membrane separation. The preparation method of the nano mixed matrix nanofiltration membrane with uniformly dispersed sulfonated hydrophenol comprises the following steps: preparing water-soluble sulfonated hydrophenol, and preparing the mixed matrix nanofiltration membrane. According to the preparation method of the nano mixed matrix nanofiltration membrane with uniformly dispersed sulfonated hydro-phenol, the compatibility of hydro-phenol organic cages and polyamide can be improved while the water solubility of the hydro-phenol organic cages can be effectively improved and the agglomeration of the hydro-phenol organic cages with small particle sizes in a water environment is inhibited, an additional water channel is further provided for the nanofiltration membrane, and the nanofiltration membrane can be used for preparing the nano mixed matrix nanofiltration membrane with uniformly dispersed sulfonated hydro-phenol. Rapid transfer of water molecules in the nanofiltration membrane is promoted, and the interception performance of the nanofiltration membrane is improved.

Description

Technical Field

[0001] The invention relates to the field of nanofiltration membrane separation, in particular to a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol and a preparation method thereof. Background Art

[0002] The increasing demand for clean, hygienic water necessitates the development of environmentally friendly technologies, such as desalination and water reuse, to produce fresh water. To meet this demand, nanofiltration (NF) membranes with a molecular weight cutoff range of 200-1000 Da are commonly used in water treatment processes. To advance membrane-based water treatment technologies, NF membranes must exhibit higher separation efficiency and lower energy consumption. This requires NF membranes to exhibit higher solute rejection and higher pure water yields. However, NF membranes often exhibit a trade-off between solute rejection and water permeability, with higher solute rejection resulting in lower water permeability. Therefore, improving the permeability of NF membranes without sacrificing selectivity remains a major challenge.

[0003] Recent advances in nanotechnology have opened up new avenues for developing thin-film nanocomposite (TFN) membranes with superior nanofiltration performance. In recent years, the introduction of hydrophilic nanoparticles into the polyamide separation layer has been an effective strategy for improving the flux and antifouling properties of nanofiltration membranes. Metal and oxide nanoparticles, such as silver, titanium dioxide, and silicon dioxide, have been used as additives to prepare nanohybrid matrix nanofiltration membranes. Inorganic nanoparticles, with their unique pore structure, high specific surface area, excellent thermal stability, and mechanical strength, can be incorporated into polymer-based membranes to improve membrane permeability, fouling resistance, and stability. However, conventional inorganic nanoparticles have high surface energy, are prone to aggregation, and exhibit poor interfacial compatibility with the polyamide network, leading to defect formation and reduced retention performance. Researchers have attempted to select porous organic materials with specialized cavity structures as channels for the rapid transport of ions or water molecules. However, existing porous organic materials have low activity and solubility, making them difficult to apply to the preparation of NF membranes.

[0004] Hydrolol is an organic molecular cage containing a cavity. Its cavity diameter (0.5 nm) is larger than that of a water molecule (0.28 nm), making it a promising transport channel for water molecules and a promising material for membrane structure regulation. While hydrolol organic cages have good solubility in polar solvents, they have poor solubility in water and tend to aggregate easily, making it difficult to evenly disperse them in the aqueous phase and, consequently, unable to effectively use them in the preparation of polyamide nanofiltration membranes.

[0005] Based on this, a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophilic phenol is provided, which can effectively improve the water solubility of hydrophilic phenol organic cages, inhibit the agglomeration between small-particle hydrophilic phenol organic cages in the water environment, and improve the compatibility of hydrophilic phenol organic cages with polyamide, further provide additional water channels for the nanofiltration membrane, promote the rapid transfer of water molecules in the nanofiltration membrane, and improve the retention performance of the nanofiltration membrane, which has important technical significance and research value. Summary of the Invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a method for preparing a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophilic phenol, which can effectively improve the water solubility of hydrophilic phenol organic cages, inhibit the agglomeration of small-particle hydrophilic phenol organic cages in an aqueous environment, and improve the compatibility of hydrophilic phenol organic cages with polyamide, further provide additional water channels for the nanofiltration membrane, promote the rapid transmission of water molecules in the nanofiltration membrane, and improve the retention performance of the nanofiltration membrane; the present invention also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophilic phenol prepared by the above method.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows: A method for preparing a nano-mixed matrix nanofiltration membrane with uniformly dispersed sulfonated hydrophilic phenol comprises the following steps: preparing water-soluble sulfonated hydrophilic phenol and preparing a mixed matrix nanofiltration membrane; The method for preparing water-soluble sulfonated hydropolone comprises adjusting deionized water to alkaline, then adding hydropolone and a functional organic small molecule, reacting at room temperature under oxygen flow, adjusting the pH to neutral, and drying to obtain water-soluble sulfonated hydropolone; The method for preparing the mixed matrix nanofiltration membrane comprises soaking the ultrafiltration membrane in an aqueous solution and an oily solution in sequence, and then subjecting the membrane to heat treatment to obtain a nano-mixed matrix nanofiltration membrane in which sulfonated hydrophenol is uniformly dispersed. The aqueous phase solution is a mixed aqueous solution of water-soluble sulfonated hydrophenol and polyamine monomers; The oil phase solution is an organic solvent solution of polyacyl chloride monomers.

[0008] Preferably, in the preparation of water-soluble sulfonated hydrophenol, the functional organic small molecule is at least one of the following: aminomethanesulfonic acid, taurine, sulfanilic acid, and aniline-2,5-disulfonic acid monosodium salt.

[0009] Preferably, in the preparation of water-soluble sulfonated hydropol, the mass fraction of hydropol in deionized water is 0.1-3 wt %; The molar ratio of hydrophenol and the functional organic small molecule in deionized water is 1:1-50.

[0010] Preferably, in the preparation of water-soluble sulfonated hydrophenol, the oxygen introduction rate is 0.1-0.2 L / min, and the reaction time at room temperature is 30-60 min.

[0011] Preferably, in the preparation of water-soluble sulfonated hydrophenol, deionized water is adjusted to an alkaline pH of 9-14.

[0012] Furthermore, the preparation method further comprises: preparing an aqueous solution; The method for preparing the aqueous phase solution comprises adjusting deionized water to be alkaline, then adding water-soluble sulfonated hydrophenol and polyamine monomer, and dispersing them uniformly to prepare the aqueous phase solution.

[0013] Preferably, the polyamine monomer in the aqueous solution is at least one of the following: piperazine, N-aminoethylpiperazine, diethylenetriamine, m-phenylenediamine, polyethyleneimine, p-phenylenediamine, melamine, and thiourea.

[0014] Preferably, in the preparation of the aqueous phase solution, the deionized water is adjusted to an alkaline pH of 10-14.

[0015] Preferably, the mass fraction of the polyamine monomer in the aqueous solution is 0.1-3.5wt%; The mass fraction of the water-soluble sulfonated hydrophenol in the aqueous solution is 0.1-2 wt %.

[0016] Furthermore, the preparation method further comprises: preparing an oil phase solution; The method for preparing the oil phase solution is to add polyacyl chloride monomers into an organic solvent and disperse them uniformly to obtain the oil phase solution.

[0017] Preferably, the polyacyl chloride monomer in the oil phase solution is at least one of the following: 1,3,5-trimesoyl chloride, isophthaloyl chloride, terephthaloyl chloride, 2,2',4,4'-biphenyltetracarboxylic acid chloride, and adipoyl chloride.

[0018] Preferably, the organic solvent in the oil phase solution is at least one of the following: n-hexane, Isopar G, benzene and toluene.

[0019] Preferably, the mass fraction of the polyacyl chloride monomer in the oil phase solution is 0.01-1 wt %.

[0020] Preferably, in the preparation of the mixed matrix nanofiltration membrane, the ultrafiltration membrane is one of the following: polysulfone ultrafiltration membrane, polyethersulfone ultrafiltration membrane, polyvinylidene chloride ultrafiltration membrane, polyvinylidene fluoride ultrafiltration membrane, polyacrylonitrile ultrafiltration membrane, sulfonated polysulfone ultrafiltration membrane.

[0021] Preferably, in the preparation of the mixed matrix nanofiltration membrane, the volume of the aqueous solution used per square centimeter of ultrafiltration membrane is 1.5-5 mL; the volume of the oil phase solution used per square centimeter of ultrafiltration membrane is 1.5-5 mL; and the volume ratio of the aqueous solution to the oil phase solution is 1:1-1.5.

[0022] Preferably, in the preparation of the mixed matrix nanofiltration membrane, the immersion time of the ultrafiltration membrane in the aqueous solution is 20-300 s; the immersion time of the ultrafiltration membrane in the oil phase solution is 30-120 s; The heat treatment temperature is 60-80°C, and the heat treatment time is 2-8 minutes.

[0023] Preferably, in the preparation of the mixed matrix nanofiltration membrane, the immersion temperature of the ultrafiltration membrane in the aqueous solution is room temperature; and the immersion temperature of the ultrafiltration membrane in the oily solution is room temperature.

[0024] A nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol is prepared by the above-mentioned preparation method.

[0025] Compared with the prior art, the present invention has the following beneficial effects: In the preparation of a nano-mixed matrix nanofiltration membrane with uniformly dispersed sulfonated hydrophilic phenol, the present invention first chemically bonds functional organic small molecules to the hydrophilic phenol organic cages through a one-step Michael addition reaction or Schiff base reaction, ionizes the hydrophilic phenol organic cages, and prepares completely water-soluble hydrophilic phenol organic cages (i.e., water-soluble sulfonated hydrophilic phenol), thereby inhibiting the agglomeration of small-particle hydrophilic phenol organic cages in an aqueous environment; then, the hydrophilic phenol is used as a water phase additive in an interfacial polymerization process and uniformly dispersedly introduced into a polyamide nanofiltration membrane; the water-soluble sulfonated hydrophilic phenol has good compatibility with the polyamide and can provide additional water channels, thereby promoting the rapid transfer of water molecules in the membrane and improving the retention performance of the nanofiltration membrane.

[0026] Furthermore, in the preparation of water-soluble sulfonated hydrocyclopentane, the present invention modifies the hydrocyclopentane organic cage to different degrees of sulfonation by controlling the molar ratio of hydrocyclopentane and functional organic small molecules, so as to improve its dispersibility and solubility in aqueous amine solution, thereby making it uniformly dispersed among the polyamide polymer chain segments, coordinating the microstructure and charge of the polyamide separation layer, and preparing a polyamide nanocomposite filtration membrane with high charge distribution pores.

[0027] Furthermore, the modified hydrophilic phenol organic cage (i.e., water-soluble sulfonated hydrophilic phenol) prepared by the present invention can not only be evenly dispersed between the polyamide polymer segments, coordinating the microstructure and charge of the polyamide dense layer pairs, but also its inherent nanopores can provide additional water molecule transmission channels.

[0028] Furthermore, in the preparation of water-soluble sulfonated hydrophenol, the functional organic small molecules used for modification, such as aminomethanesulfonic acid, taurine, sulfanilic acid, and aniline-2,5-disulfonic acid monosodium salt, have the advantages of simple structure, low cost and easy availability, and the modification method is simple, which is convenient for promotion in industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Graphs showing water flux of the mixed matrix nanofiltration membranes of Examples 1-7 and Comparative Example 1.

[0030] Figure 2 Graph showing the salt rejection of the mixed matrix nanofiltration membranes of Examples 1-7 and Comparative Example 1.

[0031] Figure 3 Graph showing the pollutant removal rates of the mixed matrix nanofiltration membranes of Examples 1-7 and Comparative Example 1.

[0032] Figure 4 This is a surface SEM image of the mixed matrix nanofiltration membrane of Example 3.

[0033] Figure 5 This is a surface SEM image of the mixed matrix nanofiltration membrane of Comparative Example 1.

[0034] Figure 6 This is a diagram showing the particle sizes of the water-soluble sulfonated hydrolanol and hydrolanol in Example 3. DETAILED DESCRIPTION

[0035] In order to provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described. It should be noted that the following detailed description is illustrative and is intended to further illustrate the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] It should be noted that the terms used herein are intended only to describe specific embodiments and are not intended to limit the exemplary embodiments of the present invention. As used herein, "first," "second," and the like are used to distinguish similar objects and are not used to describe a specific order or precedence. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] The present invention provides a method for preparing a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol, comprising the following steps: Step 1: Preparation of water-soluble sulfonated hydrocyclophenol: adding hydrocyclophenol and a functional organic small molecule to alkaline deionized water, introducing a large amount of oxygen at room temperature and stirring the mixture thoroughly to react. After the reaction, the pH of the solution is adjusted from alkaline to neutral, and the mixture is freeze-dried to obtain a yellow powder product, i.e., water-soluble sulfonated hydrocyclophenol.

[0038] In an embodiment of the present invention, the functional organic small molecule is at least one of the following: aminomethanesulfonic acid, taurine, sulfanilic acid, and aniline-2,5-disulfonic acid monosodium salt.

[0039] In the embodiment of the present invention, the mass fraction of hydrophenol in deionized water is 0.1-3 wt %, preferably 0.8-2 wt %, and more preferably 1-1.5 wt %.

[0040] In an embodiment of the present invention, the molar ratio of hydrophenol to the functional organic small molecule in deionized water is 1:1-50, preferably 1:4-50.

[0041] In an embodiment of the present invention, the alkaline deionized water is prepared by adjusting the pH of the deionized water to 9-14 using an alkaline substance (such as sodium carbonate, sodium hydroxide, potassium hydroxide, etc.) to provide an alkaline solvent environment for subsequent reactions; preferably, the pH of the deionized water is adjusted to 12-13.

[0042] In an embodiment of the present invention, the oxygen introduction rate is 0.1-0.2 L / min, the stirring speed is 250-350 rpm, and the stirring reaction time is 30-60 min.

[0043] Step 2: preparing an aqueous phase solution: adding a polyamine monomer and the water-soluble sulfonated hydrophenol prepared in step 1 into alkaline deionized water, and uniformly dispersing them by ultrasonication to obtain an aqueous phase solution.

[0044] In an embodiment of the present invention, the polyamine monomer is at least one of the following: piperazine, N-aminoethylpiperazine, diethylenetriamine, m-phenylenediamine, polyethyleneimine, p-phenylenediamine, melamine, and thiourea.

[0045] In an embodiment of the present invention, the mass fraction of the polyamine monomer in the aqueous solution is 0.1-3.5 wt %, preferably 0.5-2.5 wt %, and more preferably 0.7-1.5 wt %.

[0046] In the embodiment of the present invention, the mass fraction of the water-soluble sulfonated hydrophenol in the aqueous solution is 0.1-2 wt %, preferably 0.3-1.5 wt %, and more preferably 0.5-1 wt %.

[0047] In an embodiment of the present invention, the alkaline deionized water is prepared by adjusting the pH of the deionized water to 10-14 using an alkaline substance (such as sodium carbonate, sodium hydroxide, potassium hydroxide, etc.) to provide an alkaline solvent environment for the polyamine monomer and the water-soluble sulfonated hydrophenol; preferably, the pH of the deionized water is adjusted to 12-13.

[0048] Step 3: preparing an oil phase solution: adding a polyacyl chloride monomer to an organic solvent and uniformly dispersing the monomer by ultrasonication to obtain an oil phase solution.

[0049] In an embodiment of the present invention, the polyvalent acyl chloride monomer is at least one of the following: 1,3,5-trimesoyl chloride, isophthaloyl chloride, terephthaloyl chloride, 2,2',4,4'-biphenyltetracarboxylic acid chloride, and adipoyl chloride.

[0050] In an embodiment of the present invention, the organic solvent is at least one of the following: n-hexane, Isopar G, benzene and toluene.

[0051] In an embodiment of the present invention, the mass fraction of the polyacyl chloride monomer in the oil phase solution is 0.01-1 wt %; preferably 0.05-0.5 wt %; more preferably 0.08-0.2 wt %.

[0052] Step 4: Prepare a mixed matrix nanofiltration membrane: Under room temperature, the ultrafiltration membrane is sequentially immersed in the aqueous solution prepared in step 2 and the oily solution prepared in step 3; after immersion, the membrane is dried, and then heat-treated and then immersed in deionized water for storage to obtain a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol.

[0053] In the embodiment of the present invention, in the preparation of the mixed matrix nanofiltration membrane, the volume of the aqueous solution used per square centimeter of the ultrafiltration membrane is 1.5-5 mL, preferably 2-4.5 mL.

[0054] In the embodiment of the present invention, in the preparation of the mixed matrix nanofiltration membrane, the volume of the oil phase solution used per square centimeter of the ultrafiltration membrane is 1.5-5 mL, preferably 2-4.5 mL.

[0055] In an embodiment of the present invention, in the preparation of the mixed matrix nanofiltration membrane, the volume ratio of the aqueous phase solution to the oil phase solution is 1:1-1.5, preferably 1:1-1.2.

[0056] In the embodiment of the present invention, the ultrafiltration membrane is one of the following materials: polysulfone ultrafiltration membrane, polyethersulfone ultrafiltration membrane, polyvinylidene chloride ultrafiltration membrane, polyvinylidene fluoride ultrafiltration membrane, polyacrylonitrile ultrafiltration membrane, and sulfonated polysulfone ultrafiltration membrane.

[0057] In an embodiment of the present invention, the ultrafiltration membrane is immersed in the aqueous solution for 20-300 s, preferably 30-200 s, and more preferably 40-150 s.

[0058] In an embodiment of the present invention, the ultrafiltration membrane is immersed in the oil phase solution for 30-120 s, preferably 30-90 s, and more preferably 30-60 s.

[0059] In an embodiment of the present invention, the temperature of the heat treatment is 60-80° C., and the time of the heat treatment is 2-8 minutes.

[0060] In the embodiment of the present invention, in the preparation of the mixed matrix nanofiltration membrane, an ultrafiltration membrane is used as a substrate, and a polyamide nanofiltration membrane layer is formed on the ultrafiltration membrane by interfacial polymerization reaction, thereby obtaining a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol.

[0061] In the preparation of the nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophilic phenol in the embodiment of the present invention, the functional organic small molecules used are all strong nucleophiles with sulfonic acid groups and primary amine groups, which can undergo Schiff base reaction (cross-linking) with the carbonyl groups in oxidized hydrophilic phenol in an alkaline aqueous solution to ionize the surface of the hydrophilic phenol organic cage; by introducing sulfonic acid groups, the problems of poor dispersion and easy agglomeration of the hydrophilic phenol organic cage in the aqueous phase can be effectively overcome, and it can be used as an aqueous phase additive in the interfacial polymerization process; at the same time, by controlling the molar ratio of hydrophilic phenol and the functional organic small molecules, the sulfonation degree of sulfonated hydrophilic phenol can be precisely controlled, and then it can be uniformly dispersed and introduced into the polyamide nanofiltration membrane, ultimately overcoming the trade-off equilibrium effect of the dense polymer membrane.

[0062] The embodiment of the present invention also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0063] The present invention will be further described below with reference to some specific embodiments.

[0064] Example 1 This embodiment provides a method for preparing a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol, specifically: Step 1: Preparation of water-soluble sulfonated hydrocyclophenol: Adjust the pH of deionized water to 13, add 1 wt% hydrocyclophenol and 0.2 wt% taurine (functional organic small molecule) to the deionized water with a pH of 13, and the molar ratio of the two is 1:4. At room temperature, introduce oxygen at a rate of 0.1 L / min, and stir at 300 rpm for 40 minutes. After the reaction is completed, adjust the pH to neutral, and freeze-dry to obtain a yellow powder product (taurine-modified hydrocyclophenol), i.e., water-soluble sulfonated hydrocyclophenol.

[0065] The structural formula of taurine-modified hydrophenol is as follows: .

[0066] Step 2: Prepare an aqueous solution: adjust the pH of deionized water to 11, add 0.8 wt% piperazine (polyamine monomer) and 0.5 wt% water-soluble sulfonated hydrophenol to the deionized water with a pH of 11, and disperse them uniformly by ultrasonication to obtain an aqueous solution.

[0067] Step 3: Prepare an oil phase solution: add 0.1 wt% of trimesoyl chloride (polyacyl chloride monomer) into n-hexane (organic solvent) and disperse uniformly by ultrasonication to obtain an oil phase solution.

[0068] Step 4: Prepare a mixed matrix nanofiltration membrane: Under room temperature, immerse the polysulfone ultrafiltration membrane in an aqueous solution, take it out after soaking for 60 seconds, and use air to blow to remove excess droplets on the membrane surface; then immerse it in an oil phase solution, soak it for 30 seconds, take it out and dry it; heat treat the dried membrane, control the heat treatment temperature to 70°C, and the heat treatment time to 2 minutes; after the heat treatment is completed, soak it in deionized water for storage to obtain a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol.

[0069] The volume of the aqueous solution used per square centimeter of the polysulfone ultrafiltration membrane is 2.2 mL.

[0070] The volume of the oil phase solution used per square centimeter of polysulfone ultrafiltration membrane is 2.2 mL.

[0071] This embodiment also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0072] Example 2 In the preparation of the nano-hybrid matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophilic phenol in Example 2, except for the different molar ratio of hydrophilic phenol to taurine (functional organic small molecule) in step 1, the remaining steps are the same as those in Example 1. Specifically: Step 1: Preparation of water-soluble sulfonated hydrocyclophenol: Adjust the pH of deionized water to 13, add 1 wt% hydrocyclophenol and 0.5 wt% taurine (functional organic small molecule) to the deionized water with a pH of 13, and the molar ratio of the two is 1:10. At room temperature, introduce oxygen at a rate of 0.1 L / min, and stir at 300 rpm for 40 minutes. After the reaction is completed, adjust the pH to neutral, and freeze-dry to obtain a yellow powder product (taurine-modified hydrocyclophenol), i.e., water-soluble sulfonated hydrocyclophenol.

[0073] This embodiment also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0074] Example 3 In the preparation of the nano-hybrid matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophilic phenol in Example 3, except for the different molar ratio of hydrophilic phenol to taurine (functional organic small molecule) in step 1, the remaining steps are the same as those in Example 1. Specifically: Step 1: Preparation of water-soluble sulfonated hydrocyclophenol: Adjust the pH of deionized water to 13, add 1 wt% hydrocyclophenol and 1.5 wt% taurine (functional organic small molecule) to the deionized water with a pH of 13, and the molar ratio of the two is 1:30. At room temperature, introduce oxygen at a rate of 0.1 L / min, and stir at 300 rpm for 40 minutes. After the reaction is completed, adjust the pH to neutral, and freeze-dry to obtain a yellow powder product (taurine-modified hydrocyclophenol), i.e., water-soluble sulfonated hydrocyclophenol.

[0075] This embodiment also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0076] Example 4 In the preparation of the nano-hybrid matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophilic phenol in Example 4, except for the different molar ratio of hydrophilic phenol to taurine (functional organic small molecule) in step 1, the remaining steps are the same as those in Example 1. Specifically: Step 1: Preparation of water-soluble sulfonated hydrocyclophenol: Adjust the pH of deionized water to 13, add 1 wt% hydrocyclophenol and 2.5 wt% taurine (functional organic small molecule) to the deionized water with a pH of 13, and the molar ratio of the two is 1:50. At room temperature, introduce oxygen at a rate of 0.1 L / min, and stir at 300 rpm for 40 minutes. After the reaction is completed, adjust the pH to neutral, and freeze-dry to obtain a yellow powder product (taurine-modified hydrocyclophenol), i.e., water-soluble sulfonated hydrocyclophenol.

[0077] This embodiment also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0078] Example 5 In the preparation of the nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydroquinone in Example 5, except that the functional organic small molecule used in step 1 is aminomethanesulfonic acid, the remaining steps are the same as those in Example 3. Specifically: Step 1: Prepare water-soluble sulfonated hydrophenol: adjust the pH of deionized water to 13, add 1 wt% hydrophenol and 1.5 wt% aminomethanesulfonic acid (functional organic small molecule) to deionized water with a pH of 13, introduce oxygen at a rate of 0.1 L / min at room temperature, and stir at 300 rpm for 40 minutes; after the reaction, adjust the pH to neutral, and freeze-dry to obtain a yellow powder product (aminomethanesulfonic acid-modified hydrophenol), i.e., water-soluble sulfonated hydrophenol.

[0079] The structural formula of aminomethanesulfonic acid modified hydrophenol is as follows: .

[0080] This embodiment also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0081] Example 6 In the preparation of the nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydroquinone in Example 5, except that the functional organic small molecule used in step 1 is sulfanilic acid, the remaining steps are the same as those in Example 3. Specifically: Step 1: Prepare water-soluble sulfonated hydrophenol: Adjust the pH of deionized water to 13, add 1 wt% hydrophenol and 1.5 wt% sulfanilic acid (functional organic small molecule) to deionized water with a pH of 13, introduce oxygen at a rate of 0.1 L / min at room temperature, and stir at 300 rpm for 40 minutes; after the reaction, adjust the pH to neutral, and freeze-dry to obtain a yellow powder product (sulfanilic acid-modified hydrophenol), i.e., water-soluble sulfonated hydrophenol.

[0082] The structural formula of sulfanilic acid modified hydrophenol is as follows:

[0083] This embodiment also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0084] Example 7 In the preparation of the nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol in Example 5, except that the functional organic small molecule used in step 1 is aniline-2,5-disulfonic acid methyl sodium salt, the remaining steps are the same as those in Example 3. Specifically: Step 1: Prepare water-soluble sulfonated hydrophenol: adjust the pH of deionized water to 13, add 1 wt% hydrophenol and 1.5 wt% aniline-2,5-disulfonic acid sodium salt (functional organic small molecule) to deionized water with a pH of 13, introduce oxygen at a rate of 0.1 L / min at room temperature, and stir at 300 rpm for 40 minutes; after the reaction is completed, adjust the pH to neutral, and freeze-dry to obtain a yellow powder product (aniline-2,5-disulfonic acid sodium salt modified hydrophenol), i.e., water-soluble sulfonated hydrophenol.

[0085] The structural formula of aniline-2,5-disulfonic acid sodium salt modified hydrophenol is as follows:

[0086] This embodiment also provides a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol prepared by the above method.

[0087] Comparative Example 1 Comparative Example 1 adopts the technical solution of Example 3, except that the step 1 of preparing water-soluble sulfonated hydrophenol is omitted, and the addition of water-soluble sulfonated hydrophenol to the aqueous solution is omitted. Specifically: Step 1: Prepare an aqueous phase solution: adjust the pH of deionized water to 11, add 0.8 wt % piperazine (polyamine monomer) to the deionized water with a pH of 11, and disperse it evenly by ultrasonication to obtain an aqueous phase solution.

[0088] Step 2: Prepare an oil phase solution: add 0.1 wt% of trimesoyl chloride (polyacyl chloride monomer) into n-hexane (organic solvent) and disperse uniformly by ultrasonication to obtain an oil phase solution.

[0089] Step 3. Prepare a mixed matrix separation membrane (blank control): Under room temperature, immerse the polysulfone ultrafiltration membrane in an aqueous solution, soak for 60 seconds, take it out, and use air to blow to remove excess droplets on the membrane surface; then immerse it in an oil phase solution, soak for 30 seconds, take it out and dry it; heat treat the dried membrane, control the heat treatment temperature to 70°C, and the heat treatment time to 2 minutes; after the heat treatment is completed, immerse it in deionized water for storage to obtain a mixed matrix separation membrane.

[0090] Test Example 1 The test conditions for Examples 1-7 and Comparative Example 1 were: the feed solutions were deionized water and a 2000 mg / L magnesium sulfate aqueous solution, respectively. Before adding the feed solutions, the membrane performance test apparatus was rinsed two to three times with deionized water before testing began. Test conditions were 25°C, 6 bar. Pre-pressurization was performed for 1 hour before data recording. Data recording began after the effluent stabilized. The test lasted 1 hour. After the test, the filtrate volume was measured with a graduated cylinder, and the conductivity was measured with a conductivity meter.

[0091] Test Example 2 The test conditions for Examples 1-7 and Comparative Example 1 were: the feedstock solutions were 10 mg / L aqueous solutions of cephalexin (CA) and clindamycin phosphate (CP), respectively, with neutral, positive, and negative charge in water. Before adding the feedstock solutions, the membrane performance test apparatus was rinsed two to three times with deionized water before testing began. Test conditions were 25°C and 6 bar. Pre-pressurization was performed for 1 hour before data recording, and data recording began after the effluent stabilized. The test lasted 1 hour. After the test, the concentration of the filtered solution was measured using a high-performance liquid chromatograph.

[0092] The membrane flux and salt rejection were calculated according to formulas a and b.

[0093] Calculation formula a:

[0094] in, J Indicates flux (L·m -2 ·h-1 ), V p Indicates the volume of water actually passing through the membrane (L), A Indicates the membrane area (m 2 ), t Indicates the actual test time (h).

[0095] Calculation formula b:

[0096] in, R It indicates the retention rate of salt ions by the membrane. C p 、 C f Represent the conductivity of the permeate and the original solution respectively.

[0097] The antibiotic retention rate of the membrane was calculated according to formula c.

[0098] Calculation formula c:

[0099] in, R It represents the retention rate of antibiotics by the membrane. C p 、 C f represent the antibiotic concentrations of the permeate and original solution, respectively.

[0100] The water flux and salt rejection of the nanofiltration membranes prepared in each embodiment and comparative example were tested. The results are as follows: Figure 1 and 2 As shown, it can be seen that: (1) The data from Examples 1-7 show that the addition of water-soluble sulfonated hydrocarbyl phenol to the interfacial polymerization aqueous phase can significantly increase the water flux value. The water flux of all Examples is more than twice that of Comparative Example 1. The retention rate of magnesium sulfate is also improved to a certain extent. This is because the introduction of sulfonated hydrocarbyl phenol increases the effective membrane surface area, which can enhance the overall negative charge of the membrane surface without affecting the cross-linking degree of the polyamide layer, ultimately breaking the trade-off effect between water flux and salt rejection of dense nanofiltration membranes.

[0101] (2) The data of Examples 1-4 show that the degree of sulfonation of sulfonated hydrowheel phenol can be precisely controlled by adjusting the molar ratio of hydrowheel phenol and functional organic small molecules. As the degree of sulfonation increases, the water flux gradually increases, and the salt interception rate reaches a peak in Example 3. Finally, the molar ratio of hydrowheel phenol and functional organic small molecules in Example 3 is selected as the optimal ratio.

[0102] (3) Furthermore, in combination with Examples 5-7, it can be found that when the molar ratio of hydrophilic phenol to functional organic small molecules is 1:30, the overall performance of the membrane is optimal, indicating that regulating the molar ratio of the two has a positive promoting effect on the uniform dispersion of sulfonated hydrophilic phenol.

[0103] The membrane performance test of pollutant removal was carried out on the nanofiltration membranes prepared in each embodiment and comparative example. The results are as follows: Figure 3 As shown, it can be seen that: (1) The data of Examples 1-7 show that the introduction of water-soluble sulfonated hydrophenol as an aqueous phase additive can effectively improve the removal of neutral and negatively charged pollutants. The removal rate of each example reached 98%, achieving a high efficiency removal effect.

[0104] (2) The data of Examples 1-4 and Comparative Example 1 show that regulating the molar ratio of hydroquinone and functional organic small molecules can effectively improve the removal rate of negatively charged pollutants. The reason is that the introduced sulfonic acid groups can enhance the negative charge of the membrane surface.

[0105] Based on the above data, the SEM images of Example 3 and Comparative Example 1 are as follows: Figure 4 and Figure 5 As shown, in Example 3, the addition of water-soluble sulfonated hydropolone forms a regular Turing structure, indicating that the addition of water-soluble sulfonated hydropolone can significantly differ the diffusion rates of the monomers in the two phases at the interface, thereby forming a pleated structure. The formation of the pleated structure further confirms that the preparation method provided by the present invention can improve the separation performance and water flux of the nanofiltration membrane by adding water-soluble sulfonated hydropolone to the aqueous phase.

[0106] Based on the above data results, Figure 6 The particle size comparison of water-soluble sulfonated hydropolone and hydropolone in Example 3 shows that by adding functional organic small molecules to react with hydropolone to undergo a Schiff base reaction to connect sulfonic acid groups, the uniform dispersion of hydropolone in water can be effectively improved, so that it will not agglomerate in the aqueous phase, thereby avoiding the formation of large defects due to agglomeration during the interfacial polymerization process, and solving the problem of easy agglomeration of nanomaterials.

[0107] In summary, the method for preparing a nano-hybrid matrix nanofiltration membrane with uniformly dispersed sulfonated hydrophilic phenol provided by the present invention can effectively improve the water solubility of hydrophilic phenol organic cages, inhibit the agglomeration of small-particle hydrophilic phenol organic cages in an aqueous environment, and improve the compatibility of the hydrophilic phenol organic cages with polyamide, further providing additional water channels for the nanofiltration membrane, promoting the rapid transfer of water molecules within the nanofiltration membrane, and improving the retention performance of the nanofiltration membrane. Furthermore, the nano-hybrid matrix nanofiltration membrane with uniformly dispersed sulfonated hydrophilic phenol has high water flux, high salt rejection, and excellent pollutant removal performance, effectively overcoming the problem of poor membrane performance caused by the easy agglomeration of traditional nanomaterials. Furthermore, the preparation method is simple, which is conducive to industrial production and application.

[0108] Unless otherwise specified, all percentages used in the present invention are by mass.

[0109] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol, characterized in that: The following steps are involved: Preparation of water-soluble sulfonated hydroquinone and mixed matrix nanofiltration membrane; The method for preparing water-soluble sulfonated hydropolone comprises adjusting deionized water to alkaline, then adding hydropolone and a functional organic small molecule, reacting at room temperature under oxygen flow, adjusting the pH to neutral, and drying to obtain water-soluble sulfonated hydropolone; The method for preparing the mixed matrix nanofiltration membrane comprises soaking the ultrafiltration membrane in an aqueous solution and an oily solution in sequence, and then subjecting the membrane to heat treatment to obtain a nano-mixed matrix nanofiltration membrane in which sulfonated hydrophenol is uniformly dispersed. The aqueous phase solution is a mixed aqueous solution of water-soluble sulfonated hydrophenol and polyamine monomers; The oil phase solution is an organic solvent solution of polyacyl chloride monomers.

2. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: In the preparation of water-soluble sulfonated hydrophenol, the functional organic small molecule is at least one of the following: aminomethanesulfonic acid, taurine, sulfanilic acid, and aniline-2,5-disulfonic acid monosodium salt.

3. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: In the preparation of water-soluble sulfonated hydrocyclophenol, the mass fraction of hydrocyclophenol in deionized water is 0.1-3 wt %; The molar ratio of hydrophenol and the functional organic small molecule in deionized water is 1:1-50.

4. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: In the preparation of water-soluble sulfonated hydrophenol, the oxygen introduction rate is 0.1-0.2 L / min, and the reaction time at room temperature is 30-60 min.

5. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: The polyamine monomer in the aqueous solution is at least one of the following: piperazine, N-aminoethylpiperazine, diethylenetriamine, m-phenylenediamine, polyethyleneimine, p-phenylenediamine, melamine, and thiourea; The polyvalent acyl chloride monomer in the oil phase solution is at least one of the following: 1,3,5-trimesoyl chloride, isophthaloyl chloride, terephthaloyl chloride, 2,2',4,4'-biphenyltetracarboxylic acid chloride, and adipoyl chloride.

6. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: The mass fraction of the polyamine monomer in the aqueous solution is 0.1-3.5wt%; The mass fraction of the water-soluble sulfonated hydrophenol in the aqueous solution is 0.1-2wt%; The mass fraction of the polyacyl chloride monomer in the oil phase solution is 0.01-1 wt %.

7. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: In the preparation of the mixed matrix nanofiltration membrane, the ultrafiltration membrane is one of the following: polysulfone ultrafiltration membrane, polyethersulfone ultrafiltration membrane, polyvinylidene chloride ultrafiltration membrane, polyvinylidene fluoride ultrafiltration membrane, polyacrylonitrile ultrafiltration membrane, and sulfonated polysulfone ultrafiltration membrane.

8. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: In the preparation of the mixed matrix nanofiltration membrane, the volume of the aqueous solution used per square centimeter of the ultrafiltration membrane is 1.5-5 mL; the volume of the oil phase solution used per square centimeter of the ultrafiltration membrane is 1.5-5 mL; and the volume ratio of the aqueous solution to the oil phase solution is 1:1-1.

5.

9. The method for preparing a nano-mixed matrix nanofiltration membrane uniformly dispersed with sulfonated hydrophenol according to claim 1, characterized in that: In the preparation of the mixed matrix nanofiltration membrane, the ultrafiltration membrane is immersed in the aqueous solution for 20-300 seconds; the ultrafiltration membrane is immersed in the oil solution for 30-120 seconds; The heat treatment temperature is 60-80°C, and the heat treatment time is 2-8 minutes.

10. A nano-mixed matrix nanofiltration membrane with uniform dispersion of sulfonated hydrophenol, characterized in that: The method is prepared according to any one of claims 1 to 9.

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