A hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag and its preparation method

Abstract

This invention belongs to the field of water purification, specifically relating to a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag and its preparation method. The antibacterial water purification bag includes a membrane bag formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes together. The hydrophilic TA@MOF-based forward osmosis membranes, from the inside to the outside of the water purification bag, include a base membrane layer, a sandwich membrane layer, and a dense active layer. The base membrane layer is a polyacrylonitrile matrix membrane layer, doped with glucosamine to enhance hydrophilicity. The sandwich membrane layer is a TA@MOF particle layer, enabling selective retention and rapid water flow. The dense active layer is a modified polyamide active layer, enhancing antibacterial properties and heavy metal retention capacity. The forward osmosis antibacterial water purification bag has a simple structure, is highly portable, can be quickly started up, and effectively purifies water, making it suitable for various emergency environments.

Description

Technical Field

[0001] This invention belongs to the field of water purification, specifically relating to a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag and its preparation method. Background Technology

[0002] In special environments such as disaster emergencies, aerospace, field operations, and hiking expeditions, the lack of safe and convenient drinking water sources becomes a key factor restricting emergency response efficiency and the protection of people's lives. Therefore, developing emergency water purification devices with portability, high efficiency, and good environmental adaptability is of significant practical importance. Current water purification technologies mainly rely on ultrafiltration or reverse osmosis, and their corresponding devices have certain drawbacks. For example, pump-type water purifiers (LifeStrawGo, MSR Guardian) are expensive, energy-intensive, and have poor turbid water treatment effects; ultrafiltration water purifiers (Sawyer mini) require pressure drive, are energy-intensive, bulky, and not easy to carry. Compared to traditional membrane methods such as ultrafiltration, forward osmosis (FO) is a membrane separation process that uses a high osmotic pressure draw liquid as the driving force to allow water molecules to migrate from low-concentration raw water to the high-concentration solution side through a semi-permeable membrane. It has advantages such as zero energy consumption, simple operation, and high purification accuracy, and is particularly suitable for emergency scenarios with limited power and complex water quality.

[0003] Existing forward osmosis water purification devices suffer from systemic shortcomings in three dimensions: structural design, membrane fouling tolerance, and stability in extreme environments. This prevents them from meeting the core requirements of "ready to use, qualified purification, and lightweight" in emergency scenarios, thus limiting their widespread application in emergency situations. Therefore, the development of a portable emergency water purification system that is simple in structure, lightweight, easy to carry, and possesses excellent purification performance is crucial to meeting the rapid response needs for drinking water safety in emergencies. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag and its preparation method. The antibacterial water purification bag comprises a membrane bag formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes. The hydrophilic TA@MOF-based forward osmosis membrane consists of a base membrane layer, an interlayer membrane layer, and a dense active layer. The base membrane layer is a polyacrylonitrile matrix membrane doped with glucosamine to enhance hydrophilicity; the interlayer membrane layer is a TA@MOF particle layer formed by tannic acid-modified MOF, achieving selective retention and rapid water flow; the dense active layer is an active layer formed by chitosan-modified polyamide, possessing antibacterial and heavy metal retention functions. The antibacterial water purification bag has a simple structure, is easy to carry, has excellent hydrophilicity, strong resistance to contamination, good antibacterial properties, and rapid start-up, making it suitable for drinking water purification in harsh emergency environments.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The purpose of this invention is to provide a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag. The antibacterial water purification bag includes a membrane bag, which is formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes together. The hydrophilic TA@MOF-based forward osmosis membrane includes, from the inside to the outside of the water purification bag, a base membrane layer, an interlayer membrane layer, and a dense active layer. The base membrane layer is a polyacrylonitrile matrix membrane layer, which is doped with glucosamine at a doping amount of 4wt.% to 6wt.%. The interlayer membrane layer is a TA@MOF particle layer formed by tannic acid-modified MOF. The dense active layer is an active layer formed by chitosan-modified polyamide.

[0007] In a preferred embodiment of the present invention, the thickness of the base film layer is 50μm~150μm, the thickness of the interlayer film layer is 1μm~20μm, and the thickness of the dense active layer is 50nm~100nm.

[0008] In a preferred embodiment of the present invention, the method for preparing a polyacrylonitrile matrix membrane includes the following steps:

[0009] S1. Add glucosamine and a pore-forming agent to the polyacrylonitrile solution and perform degassing treatment to form a casting solution.

[0010] S2. The casting solution is coated onto the substrate by immersion precipitation and then dried to obtain a polyacrylonitrile matrix film.

[0011] In a preferred embodiment of the present invention, the casting solution is composed of the following components by mass percentage: 8%~9% polyacrylonitrile, 4%~6% glucosamine, 83% mixed solvent and 3%~4% pore-forming agent, totaling 100%; wherein, the mixed solvent is composed of the following components by mass percentage: 70%~80% N-methylpyrrolidone, 15%~25% dimethylformamide and 3%~10% water, totaling 100%; the pore-forming agent is a mixture of polyethylene glycol and sodium chloride in a mass ratio of 1.5~3:1.

[0012] In a preferred embodiment of the present invention, the method for preparing a hydrophilic TA@MOF-based forward osmosis membrane includes the following steps:

[0013] S1. The TA@MOF particle dispersion is filtered onto the surface of the base film layer by vacuum filtration, so that the TA@MOF particles are dispersed on the surface of the base film layer to form a TA@MOF sandwich layer.

[0014] S2. Using interfacial polymerization, the TA@MOF membrane layer is sequentially immersed in an aqueous phase containing an aromatic diamine and an organic phase containing trichlorobenzoyl chloride monomers, followed by heat treatment to form a polyamide membrane layer. Subsequently, the polyamide membrane layer is activated to obtain an activated polyamide membrane layer. The activated polyamide membrane layer is then immersed in a chitosan solution, allowing chitosan to be adsorbed onto the surface of the polyamide membrane, forming a chitosan-adsorbed polyamide membrane. The chitosan-adsorbed polyamide membrane is dissolved in a glutaraldehyde solution, resulting in a crosslinking reaction that forms an active layer of chitosan-modified polyamide on the surface of the TA@MOF membrane layer, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0015] In a preferred embodiment of the present invention, the vacuum filtration pressure is 0.01 MPa to 0.1 MPa; the filtration time is 0.5 min to 10 min; and the concentration of the TA@MOF dispersion is 0.1 mg / mL to 5 mg / mL.

[0016] In a preferred embodiment of the present invention, the aromatic diamine is m-phenylenediamine; the trichlorobenzoyl chloride monomer is trimesoyl chloride; the activation treatment is soaking in an acidic solution for 5 min to 15 min, the acidic solution being hydrochloric acid with a concentration of 0.01 mol / L to 0.1 mol / L; the chitosan solution contains 0.1 wt.% to 1.5 wt.% chitosan by mass, and the solvent is an acetic acid solution with a mass fraction of 0.5 wt.%; the soaking time is 15 min to 60 min; the glutaraldehyde solution concentration is 0.05 wt.% to 0.5 wt.%; and the crosslinking time is 10 min to 60 min.

[0017] In a preferred embodiment of the present invention, the method for preparing TA@MOF dispersion includes the following steps:

[0018] S1. Dissolve the metal ions and ligands in a solvent, add tannic acid, and react at 25℃~120℃ to obtain TA@MOF particles.

[0019] S2. Disperse TA@MOF particles in water and sonicate to obtain TA@MOF dispersion.

[0020] In a preferred embodiment of the present invention, the ligand is an imidazole ligand or a carboxyl ligand, and the metal ion is a transition metal element; the molar ratio of tannic acid to metal ion is 0.05~0.5:1, the molar ratio of tannic acid to ligand is 0.05~0.5:1, and the reaction time is 1h~24h.

[0021] Another object of the present invention is to provide a method for preparing the above-mentioned hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, comprising the following steps:

[0022] S1. Two hydrophilic TA@MOF-based forward osmosis membranes are bonded together, and the bonded ends are heat-sealed to form a membrane bag with an opening. The dense active layer of the TA@MOF-based forward osmosis membrane is located on the outside.

[0023] S2. Inject the absorbent into the membrane bag through the opening, and seal the opening to obtain a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention provides a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, the antibacterial water purification bag comprising a membrane bag, the membrane bag being formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes together, the hydrophilic TA@MOF-based forward osmosis membrane being composed of a base membrane layer, an interlayer membrane layer and a dense active layer. The base membrane layer is a polyacrylonitrile matrix membrane layer, providing mechanical support as the bottom layer of the forward osmosis membrane. Its doping with glucosamine enhances hydrophilicity, reduces the interfacial contact angle, decreases internal concentration polarization, and strengthens the adhesion to other membrane layers to prevent delamination. The sandwich layer is a TA@MOF particle layer formed by tannic acid-modified MOF. TA@MOF particles can construct secondary selective channels, enabling selective retention of macromolecules or pollutants, rapid water and small ion flow, and improved interfacial roughness. Simultaneously, TA modification enhances hydrophilicity, and phenolic hydroxyl groups provide metal complexation capabilities, enhancing antibacterial and antifouling properties. The dense active layer is an active layer formed by chitosan-modified polyamide, possessing stable antibacterial function and the ability to retain heavy metal ions and harmful substances. Chitosan adsorption and glutaraldehyde crosslinking modification improve hydrophilicity, accelerating the contact and dissolution of the drying agent with water, rapidly forming a high osmotic pressure differential, and shortening the water purification start-up waiting time. This forward osmosis membrane structure combines high permeability, high selectivity, high fouling resistance, and antibacterial properties, making it suitable for drinking water purification in various harsh emergency environments. The antibacterial water purification bag features a simple structure, high portability, high water purification efficiency, resistance to contamination, antibacterial and heavy metal retention functions, and effectively shortens the start-up time. It is suitable for use in various emergency environments, significantly improving user experience and ensuring drinking water safety. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the antibacterial water purification bag prepared according to the present invention.

[0027] Figure 2 This is a physical image of the antibacterial water purification bag produced by this invention.

[0028] Figure 3 These are test diagrams of the contact angle of the forward osmosis membrane in Examples 1 to 3 of the present invention.

[0029] Figure 4 This is a test diagram of the contact angle of the forward osmosis membrane in Comparative Example 1 of the present invention.

[0030] Figure 5 This is a graph showing the pollutant removal rate and water production of the disaster emergency water purification bag of Embodiment 1 of the present invention.

[0031] Figure 6 This is a graph showing the pollutant removal rate and water production of the outdoor hiking-type water purification bag of Embodiment 2 of the present invention.

[0032] Figure 7 This is a graph showing the pollutant removal rate and water production of the downhole operation type water purification bag in Embodiment 3 of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that the technical terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased commercially or prepared by existing methods. In this invention, polyacrylonitrile is abbreviated as PAN, N-methylpyrrolidone as NMP, tannic acid as TA, dimethylformamide as DMF, and polyethylene glycol as PEG-2000.

[0035] Existing forward osmosis water purification devices suffer from systemic shortcomings in three dimensions: structural design, membrane fouling tolerance, and stability in extreme environments. These shortcomings prevent them from meeting the core requirements of "ready to use, qualified purification, and lightweight" in emergency scenarios, thus limiting their widespread application in emergency situations. Therefore, developing a portable emergency water purification system that is simple in structure, lightweight, easy to carry, and possesses excellent purification performance to meet the rapid response needs for drinking water safety in emergencies is a current challenge.

[0036] Based on this, on the one hand, the present invention provides a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, the antibacterial water purification bag comprising a membrane bag, the membrane bag being formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes together; the hydrophilic TA@MOF-based forward osmosis membrane comprises, from bottom to top along the thickness direction, a base membrane layer, an interlayer membrane layer, and a dense active layer; the base membrane layer is a polyacrylonitrile matrix membrane layer, the polyacrylonitrile matrix membrane layer being doped with glucosamine, the doping amount of glucosamine being 4wt.%~6wt.%; the interlayer membrane layer is a TA@MOF particle layer formed by tannic acid-modified MOF; and the dense active layer is an active layer formed by chitosan-modified polyamide.

[0037] It should be noted that the reaction principle and function of each membrane layer in the hydrophilic TA@MOF-based forward osmosis membrane are as follows:

[0038] (1) Membrane reaction principle: The mixed solvent diffuses rapidly outward, and the non-solvent (water) enters the membrane solution, resulting in phase separation. The pore-forming agent dissolves in water, forming a porous structure. The doped glucosamine is uniformly dispersed in the membrane matrix, and its hydrophilic groups are solidified on the inner wall of the membrane. Function: The membrane serves as the bottom layer of the forward osmosis membrane, providing mechanical support; the purpose of doping it with glucosamine containing amino and hydroxyl groups is to improve the hydrophilicity of the membrane, reduce the interfacial contact angle, and help reduce internal concentration polarization; at the same time, it improves the interfacial bonding force, and the hydrophilic groups enhance the bonding force with the intermediate TA@MOF layer and the upper polyamide active layer, preventing delamination.

[0039] (2) Membrane layer reaction principle: TA is adsorbed onto the MOF surface through hydrogen bonding and coordination to form a surface coating layer. TA modification makes the particles hydrophilic, while providing metal complexing ability through phenolic hydroxyl groups. Function: The intermediate membrane layer TA@MOF first constructs secondary selective channels. The ordered nanopores of MOF selectively trap macromolecules or pollutants, allowing water and small ions to pass through quickly. Secondly, it improves the interface roughness. After TA coating the MOF particles, the surface is more uniform, which is conducive to the formation of a dense and uniform polyamide active layer. At the same time, TA modification makes the particles hydrophilic, while providing metal complexing ability through phenolic hydroxyl groups, enhancing antibacterial and antifouling properties.

[0040] (3) Principle of Dense Active Layer Reaction: A modified polyamide active layer is prepared on the surface of the TA@MOF layer using interfacial polymerization. The aqueous phase contains polyamine monomers, and the organic phase contains acyl chloride monomers. A condensation reaction occurs at the interface of the two phases to generate polyamide. A hydrophilic modifier is introduced to form a partially gelled hydrophilic porous structure on the surface. Function: The modified polyamide active layer also serves as a hydrophilic gel coating, which promotes the rapid penetration of water molecules. The high hydrophilicity and porous structure of the gel coating increase the contact rate between the desiccant powder and water inside the water purification bag, accelerate the dissolution process, and quickly form a high osmotic pressure difference, thereby significantly shortening the start-up waiting time of the water purification bag.

[0041] The forward osmosis membrane structure combines high water permeability, high selectivity, high fouling resistance, and antibacterial properties, making it suitable for drinking water purification in various harsh emergency environments.

[0042] The thickness of the base membrane layer is 50 μm to 150 μm, the thickness of the interlayer membrane layer is 1 μm to 20 μm, and the thickness of the dense active layer is 50 nm to 100 nm. In the preparation of the forward osmosis composite membrane, membrane thickness has a significant impact on membrane structure and performance: when the base membrane is too thick, the solvent-non-solvent exchange rate slows down, and a dense structure is easily formed. Although this provides better mechanical strength and operational stability, it exacerbates internal concentration polarization and reduces water flux. When the base membrane is too thin, the mass transfer path is short and the internal concentration polarization is weak, which is beneficial for improving water flux and selectivity. However, it is prone to producing through-hole macropores or collapse during phase transformation, making it difficult to obtain a uniform, defect-free active layer during interfacial polymerization, and resulting in insufficient mechanical strength during film formation and use. To balance flux and strength, the thickness of the support layer is usually controlled in the range of 50μm to 150μm in actual preparation. By optimizing the concentration of the casting solution, the thickness of the membrane and the phase transformation conditions, a thin and porous base membrane, a uniform intermediate functional layer and an ultra-thin and dense polyamide active layer can be achieved, thereby obtaining a forward osmosis membrane with high flux, high selectivity and high stability.

[0043] The method for preparing the polyacrylonitrile matrix membrane includes the following steps: adding glucosamine and a pore-forming agent to a polyacrylonitrile solution, performing degassing treatment to form a casting solution; coating the casting solution onto a substrate using an immersion precipitation method, and drying to obtain the polyacrylonitrile matrix membrane. The matrix membrane prepared by the above method has good hydrophilicity and pore structure.

[0044] In one specific embodiment, the polyacrylonitrile solution is formed by adding PAN powder to a mixed solvent, stirring at 60°C for 4-8 hours to completely dissolve it, and then cooling to 40°C.

[0045] The casting solution is composed of the following components by mass percentage: 8%~9% polyacrylonitrile, 4%~6% glucosamine, 83% mixed solvent, and 3%~4% pore-forming agent, totaling 100%; wherein, the mixed solvent is composed of the following components by mass percentage: 70%~80% N-methylpyrrolidone, 15%~25% dimethylformamide, and 3%~10% water, totaling 100%; the pore-forming agent is a mixture of polyethylene glycol and sodium chloride in a mass ratio of 1.5~3:1.

[0046] The method for preparing the hydrophilic TA@MOF-based forward osmosis membrane includes the following steps:

[0047] S1. The TA@MOF particle dispersion is filtered onto the surface of the base film layer by vacuum filtration, so that the TA@MOF particles are dispersed on the surface of the base film layer to form a TA@MOF sandwich layer.

[0048] S2. Using interfacial polymerization, the TA@MOF membrane layer is sequentially immersed in an aqueous phase containing an aromatic diamine and an organic phase containing trichlorobenzoyl chloride monomers, followed by heat treatment to form a polyamide membrane layer. Subsequently, the polyamide membrane layer is activated to obtain an activated polyamide membrane layer. The activated polyamide membrane layer is then immersed in a chitosan solution, allowing chitosan to be adsorbed onto the surface of the polyamide membrane, forming a chitosan-adsorbed polyamide membrane. The chitosan-adsorbed polyamide membrane is dissolved in a glutaraldehyde solution, resulting in a crosslinking reaction that forms an active layer of chitosan-modified polyamide on the surface of the TA@MOF membrane layer, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0049] The vacuum filtration pressure is 0.01 MPa to 0.1 MPa, and the filtration time is 0.5 min to 10 min. The purpose is to ensure that the thickness of the membrane layer and the uniformity of the particles are appropriate.

[0050] The preparation method of the TA@MOF dispersion includes the following steps: dissolving metal ions and ligands in a solvent, adding tannic acid, and reacting at 25℃~120℃ to obtain TA@MOF particles; dispersing the TA@MOF particles in water and sonicating to obtain the TA@MOF dispersion. The ligands are not limited to imidazole or carboxyl ligands, and the metal ions are transition metal elements; the molar ratio of tannic acid to metal ions or ligands is 0.05~0.5:1; the reaction time is 1h~24h. The concentration of the TA@MOF dispersion is 0.1mg / mL~5mg / mL. The tannic acid is used as a functionalizing reagent. By controlling the molar ratio of tannic acid to metal ions or ligands, effective doping or surface coating of tannic acid in the MOF nucleus and growth process is achieved; then, the reaction conditions, including temperature, reaction time, pH, and stirring rate, are adjusted to obtain two-dimensional TA@MOF particles with uniform morphology and uniform tannic acid distribution.

[0051] The aromatic diamines mentioned include, but are not limited to, m-phenylenediamine; trichlorobenzoyl chloride acyl chloride monomers include, but are not limited to, pyromellitic trimethylolpropionate chloride.

[0052] The activation treatment includes, but is not limited to: soaking in an acidic solution for 5 to 15 minutes; the acidic solution is hydrochloric acid with a concentration of 0.01 mol / L to 0.1 mol / L. The purpose of the activation treatment is to increase the hydroxyl and amino content on the surface of the polyurethane film for subsequent chemical crosslinking.

[0053] The chitosan solution contains 0.1 wt.% to 1.5 wt.% chitosan by mass, and the solvent is an acetic acid solution with a mass fraction of 0.5 wt.%. The polyamide membrane is immersed in the chitosan solution for 15 min to 60 min, the purpose of which is to allow the chitosan to be fully adsorbed onto the membrane surface.

[0054] The glutaraldehyde solution concentration is 0.05wt.%~0.5wt.%, and the crosslinking time is 10min~60min. The purpose is to utilize the aldehyde groups of glutaraldehyde to react with the amino groups of chitosan to form a stable network structure. After the crosslinking reaction, the modified polyamide active layer needs to be washed with water to remove unreacted substances and dried at below 50℃ to obtain a modified polyamide active layer with stable antibacterial function and enhanced ability to retain heavy metal ions and harmful substances.

[0055] The antibacterial water purification bag designed in this invention has a simple structure, is highly portable, has high water purification efficiency, is resistant to pollution, has antibacterial and heavy metal interception functions, and effectively shortens the start-up time. It is suitable for use in a variety of emergency environments, significantly improving user experience and drinking water safety.

[0056] On the other hand, the present invention provides a method for preparing a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, comprising the following steps:

[0057] S1. Two hydrophilic TA@MOF-based forward osmosis membranes are bonded together, and the bonded ends are heat-sealed to form a membrane bag with an opening. The dense active layer of the TA@MOF-based forward osmosis membrane is located on the outside.

[0058] S2. Inject the absorbent into the membrane bag through the opening, and seal the opening to obtain a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag.

[0059] The hydrophilic TA@MOF-based forward osmosis membrane requires pretreatment. The pretreatment steps involve air-drying the hydrophilic TA@MOF-based forward osmosis membrane at room temperature, then immersing it in a 40 wt.% glycerol aqueous solution for 4-6 hours, followed by further drying at room temperature. In practical use, since water permeates into the membrane bag after contact with the hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, a waterproof packaging layer is provided outside the membrane bag. This waterproof packaging layer can be a pre-sealed plastic bag made of PA / PE composite membrane, thus obtaining an antibacterial water purification bag with a double-layer protective structure. During use, the packaging layer is removed, and the bag is immersed in water for water absorption. The structure of the double-layer protective antibacterial water purification bag is as follows... Figure 1 As shown, it consists of a plastic seal bag 1, a film bag 2, an absorbent 3, a drinking spout 4, and a purified water tank 5.

[0060] The composition of the extractant varies depending on the application scenario. In specific embodiments, a lemon-based energy extractant composed of glucose, citric acid, and honey powder is suitable for disaster emergencies; an anti-fatigue functional extractant composed of caffeine, taurine, and fructose is suitable for outdoor hiking; and an electrolyte functional extractant composed of sodium citrate, potassium chloride, and glycine is suitable for downhole operations.

[0061] The following specific examples will provide further explanation.

[0062] Example 1

[0063] A method for preparing a disaster emergency-grade hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag includes the following steps:

[0064] S1. Dissolve 8g of PAN in 83g of a mixed solvent consisting of 75% NMP, 20% DMF, and 5% water. Stir at 60℃ for 5h until completely dissolved to obtain a PAN solution. Cool the PAN solution to 40℃, add 6g of glucosamine, and stir for 1h. Then add 1.5g of PEG-2000 and 1.5g of NaCl particles, stir to disperse, and let stand for 24h to degas, obtaining a casting solution. Apply the casting solution to a nonwoven fabric substrate using an immersion precipitation method, immerse it in a 25℃ pure water bath for phase inversion for 10s, wash with water, and dry at 40℃ to obtain a hydrophilic polyacrylonitrile matrix membrane, i.e., the base layer membrane.

[0065] S2. Dissolve 0.3 mmol of Zn(NO3)2·6H2O and 1.2 mmol of 2-methylimidazole in methanol, add 0.05 mmol of tannic acid, and react at 25 °C for 12 h. After centrifugation and washing, TA@ZIF-8 particles are obtained. Disperse 20 mg of TA@ZIF-8 particles in deionized water with a concentration of 2 mg / mL, sonicate for 30 min, and then vacuum filter on the surface of the base membrane at a pressure of 0.06 MPa for 5 min to form a uniform sandwich layer.

[0066] S3. Immerse the membrane layer in a 2 wt.% m-phenylenediamine aqueous solution for 60 seconds, remove excess solution and drain. Then immerse it in a 0.2 wt.% trimesoyl chloride n-hexane solution for 1 minute, remove excess solution, and heat treat for 10 minutes to form a polyamide layer. Activate the surface of the polyamide layer with a 0.05 mol / L HCl solution for 10 minutes. Then immerse the polyamide layer in a 1.5 wt.% chitosan solution for 30 minutes. The chitosan solution is obtained by dissolving chitosan in a 0.5 wt.% acetic acid solution, and then transfer it to a 0.2 wt.% glutaraldehyde solution for a crosslinking reaction for 20 minutes. Wash with water and dry at 45°C to obtain the active layer formed by chitosan-modified polyamide, thus obtaining the hydrophilic TA@MOF-based forward osmosis membrane.

[0067] S4. Take two hydrophilic TA@MOF-based forward osmosis membranes prepared in S3, each membrane measuring 10cm × 15cm. Air dry at room temperature, then immerse them in a 40wt.% glycerol aqueous solution for 6 hours. After 6 hours, dry at room temperature to obtain pretreated hydrophilic TA@MOF-based forward osmosis membranes. With the active layer of the pretreated hydrophilic TA@MOF-based forward osmosis membrane facing outwards, heat-seal three sides of both membranes using a heat-sealing machine to form a forward osmosis membrane bag. Inject the extractant from the open end. The extractant is a dried lemon energy-type extractant, composed of 30g glucose, 5g citric acid, and 5g honey powder. Then, seal the edges of the membrane bag using a heat-sealing machine. Finally, place the membrane bag into a pre-made 20cm × 25cm plastic-sealed bag made of PA / PE composite membrane to obtain an antibacterial water purification bag with a double-layer protective structure, i.e., a disaster emergency water purification bag. Figure 2 As shown.

[0068] The effective area of ​​the disaster emergency water bag is 300 cm². 2 The disaster emergency water bag is suitable for use with river water and surface water in flooded areas during disaster emergency scenarios. Specifically, the water quality must contain >10 mg / L of Vibrio cholerae. 6 CFU / mL, Pb in heavy metals 2+ / Cd 2+ ≤0.5mg / L, suspended solids content is 50NTU~200NTU.

[0069] Example 2

[0070] A method for preparing an outdoor hiking-type hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag includes the following steps:

[0071] S1. Dissolve 9g of PAN in 83g of a mixed solvent consisting of 75% NMP, 20% DMF, and 5% water. Stir at 60℃ for 8 hours until completely dissolved to obtain a PAN solution. Cool the PAN solution to 40℃, add 4g of glucosamine, and stir for 1 hour. Then add 2.5g of PEG-2000 and 1.5g of NaCl particles, stir to disperse, and let stand for 24 hours to remove bubbles, obtaining a casting solution. Apply the casting solution to a nonwoven fabric substrate using an immersion precipitation method, immerse it in a 25℃ pure water bath for phase inversion for 10 seconds, wash with water, and dry at 40℃ to obtain a hydrophilic polyacrylonitrile matrix membrane, i.e., the base layer membrane.

[0072] S2. Dissolve 0.5 mmol of Zn(NO3)2·6H2O and 2 mmol of 2-methylimidazole in methanol, add 0.08 mmol of tannic acid, and react at 25 °C for 12 h. After centrifugation and washing, TA@ZIF-8 particles are obtained. Disperse 30 mg of TA@ZIF-8 particles in deionized water with a concentration of 2 mg / mL, sonicate for 30 min, and then vacuum filter on the surface of the base membrane at a pressure of 0.03 MPa for 5 min to form a uniform sandwich layer.

[0073] S3. The membrane layer is immersed in a 1.5 wt.% m-phenylenediamine aqueous solution for 90 seconds, excess solution is removed and drained, then immersed in a 0.15 wt.% trimesoyl chloride n-hexane solution for 1 minute, excess solution is removed, and heat-treated for 8 minutes to form a polyamide layer. The surface of the polyamide layer is activated with a 0.05 mol / L HCl solution for 10 minutes; then the polyamide layer is immersed in a 1.5 wt.% chitosan solution for 30 minutes. The chitosan solution is obtained by dissolving chitosan in a 0.5 wt.% acetic acid solution, and then transferred to a 0.2 wt.% glutaraldehyde solution for crosslinking reaction for 15 minutes; washed with water and dried at 45°C, the active layer formed by chitosan-modified polyamide is obtained, thus obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0074] S4. Take two hydrophilic TA@MOF-based forward osmosis membranes prepared in S3, each membrane measuring 10cm × 15cm. Air dry at room temperature, then immerse them in a 40wt.% glycerol aqueous solution for 6 hours. After drying at room temperature, a pretreated hydrophilic TA@MOF-based forward osmosis membrane is obtained. With the active layer of the pretreated hydrophilic TA@MOF-based forward osmosis membrane facing outwards, heat-seal three sides of the two membranes using a heat-sealing machine to form a forward osmosis membrane bag. Inject the extractant from the open end. The extractant is a drying and anti-fatigue functional extractant composed of 2g caffeine, 3g taurine, and 35g fructose. Then, seal the edges of the membrane bag using a heat-sealing machine. Finally, place the membrane bag into a pre-made 20cm × 25cm plastic-sealed bag made of PA / PE composite membrane to obtain an antibacterial water purification bag with a double-layer protective structure, i.e., an outdoor hiking-type water purification bag.

[0075] The effective area of ​​the obtained outdoor hiking water bladder is 300 cm². 2 Outdoor hiking water bladders are suitable for use in mountain streams and high-altitude lakes during outdoor hiking activities. Specifically, the water quality must contain >10 Cryptosporidium oocysts. 3 Organic micropollutants ≤0.1 mg / L, pesticide concentration ≤0.1 mg / L.

[0076] Example 3

[0077] A method for preparing a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag for downhole operations includes the following steps:

[0078] S1. Dissolve 9g of PAN in 83g of a mixed solvent consisting of 75% NMP, 20% DMF, and 5% water. Stir at 60℃ for 8 hours until completely dissolved to obtain a PAN solution. Cool the PAN solution to 40℃, add 4g of glucosamine, and stir for 1 hour. Then add 2.5g of PEG-2000 and 1.5g of NaCl particles, stir to disperse, and let stand for 24 hours to remove bubbles, obtaining a casting solution. Apply the casting solution to a nonwoven fabric substrate using an immersion precipitation method, immerse it in a 25℃ pure water bath for phase inversion for 10 seconds, wash with water, and dry at 40℃ to obtain a hydrophilic polyacrylonitrile matrix membrane, i.e., the base layer membrane.

[0079] S2. Dissolve 0.2 mmol of Zn(NO3)2·6H2O and 0.8 mmol of 2-methylimidazole in methanol, add 0.03 mmol of tannic acid, and react at 25 °C for 12 h. After centrifugation and washing, TA@ZIF-8 particles are obtained. Disperse 15 mg of TA@ZIF-8 particles in deionized water with a concentration of 2 mg / mL, sonicate for 30 min, and then vacuum filter on the surface of the base membrane at a pressure of 0.06 MPa for 10 min to form a uniform sandwich layer.

[0080] S3. Immerse the membrane layer in a 2 wt.% m-phenylenediamine aqueous solution for 120 s, remove excess solution and drain. Then immerse it in a 0.1 wt.% trimesoyl chloride n-hexane solution for 1 min, remove excess solution, and heat treat for 5 min to form a polyamide layer. Activate the surface of the polyamide layer with a 0.1 mol / L HCl solution for 10 min. Then immerse the polyamide layer in a 1.5 wt.% chitosan solution for 30 min. The chitosan solution is obtained by dissolving chitosan in a 0.5 wt.% acetic acid solution, and then transferred to a 0.2 wt.% glutaraldehyde solution for crosslinking reaction for 15 min. Wash with water and dry at 45℃ to obtain the active layer formed by chitosan-modified polyamide, thus obtaining the hydrophilic TA@MOF-based forward osmosis membrane.

[0081] S4. Take two hydrophilic TA@MOF-based forward osmosis membranes prepared in S3, each membrane measuring 10cm × 15cm. Air dry at room temperature, then immerse them in a 40wt.% glycerol aqueous solution for 6 hours. After 6 hours, dry at room temperature to obtain pretreated hydrophilic TA@MOF-based forward osmosis membranes. With the active layer of the pretreated hydrophilic TA@MOF-based forward osmosis membrane facing outwards, heat-seal three sides of the two membranes using a heat-sealing machine to form a forward osmosis membrane bag. Inject the extractant from the open end. The extractant is a dry electrolyte functional extractant, composed of 2g sodium citrate, 3g potassium chloride, and 35g glycine. Then, seal the edges of the membrane bag using a heat-sealing machine. Finally, place the membrane bag into a pre-made 20cm × 25cm plastic-sealed bag made of PA / PE composite membrane to obtain an antibacterial water purification bag with a double-layer protective structure, i.e., a downhole operation type water purification bag.

[0082] The effective area of ​​the obtained downhole water bag is 300 cm². 2 The underground operation water bag is suitable for mine water inrush and rock seepage in emergency underground operation scenarios. The water mainly contains heavy metal ions, such as iron, manganese, lead, zinc, and copper.

[0083] Comparative Example 1

[0084] The difference from Example 1 is that unmodified ZIF-8 is used instead of TA@ZIF-8 particles.

[0085] Performance tests were conducted on the forward osmosis membranes used in Examples 1-3 and Comparative Example 1. The hydrophilicity of the membrane surface was characterized by measuring the contact angle of deionized water droplets under static conditions using a contact angle meter. The water flux of the membrane was measured using a self-built forward osmosis testing device, which mainly consisted of a feed side and draw solution, a flat-plate membrane tank, a circulation system, and a measurement and recording system. The draw solution volume was recorded over time, and the flux was calculated based on the unit time and effective membrane area. The water flux calculation formula is:

[0086] .

[0087] Where ΔV is the change in volume of the suction chamber (L), and A is the effective membrane area (m²). 2 ), where Δt is the test time (h).

[0088] Figure 3 These are test diagrams of the contact angle of the forward osmosis membrane in Examples 1 to 3 of the present invention. Figure 4 This is a test diagram of the contact angle of the forward osmosis membrane in Comparative Example 1 of the present invention. (From...) Figure 3 and Figure 4It can be seen that the hydrophilic surface contact angle of the forward osmosis membrane in Example 1 is 45.1°, that of the forward osmosis membrane in Example 2 is 43.6°, that of the forward osmosis membrane in Example 3 is 44.7°, and that of the forward osmosis membrane in Comparative Example 1 is 65.2°. This indicates that the contact angle of the non-tannic acid-modified forward osmosis membrane in Comparative Example 1 is significantly larger than that of the TA@MOF-based forward osmosis membranes in Examples 1-3, and the hydrophilicity of the membrane surface is reduced.

[0089] Water flux testing showed that the pure water flux of the forward osmosis membrane in Example 1 was 28.7 L·m⁻¹. -2 ·h -1 The pure water flux of the forward osmosis membrane in Example 2 was 35.4 L·m. -2 ·h -1 The pure water flux of the forward osmosis membrane in Example 3 was 30.6 L·m. -2 ·h -1 The pure water flux of the forward osmosis membrane in Comparative Example 1 was 16.8 L·m⁻¹. -2 ·h -1 This indicates that the non-tannic acid-modified forward osmosis membrane in Comparative Example 1 has a lower water flux and poorer purification efficiency compared to the TA@MOF-based forward osmosis membranes in Examples 1-3.

[0090] The antibacterial water purification bags prepared in Examples 1 to 3 were tested for use. The disaster emergency water purification bag in Example 1 used flood-polluted river water as its raw material, containing 50 NTU of suspended solids and 10 NTU of E. coli. 6 CFU / mL, Pb 2 + The concentration was 0.5 mg / L. Example 2, an outdoor hiking-type water purification bag, used mountain stream water as the raw material, containing 1200 Cryptosporidium cells / L and 0.08 mg / L of glyphosate pesticide. Example 3, an underground operation-type water purification bag, used mine water as the raw material, containing Fe2+ ions. 3+ Mn 2+ Pb 2+ Zn 2+ and Cu 2+The specific process is as follows: ① Influent sampling: Place the water purification bag in the water source to be treated, allowing the raw material liquid to flow naturally into the bag until the water chamber is full. ② Waiting for infiltration: Depending on the water quality, let it stand for 10-30 minutes; the water volume in the inner bag will gradually increase. ③ The pollutant content in the water is tested using a turbidimeter, plate count method, and ICP-OES. Specifically, the removal effect of *E. coli* is evaluated by detecting the number of colony-forming units (CFU / mL) in the influent and product water samples using the membrane filtration-plate count method; the content of organic micropollutants is determined by high-performance liquid chromatography (HPLC); the parasite content is determined by direct microscopic counting; and the removal effect of heavy metal ions is determined by measuring the concentration of metal ions in the influent and product water using inductively coupled plasma optical emission spectrometry (ICP-OES) and calculating the rejection rate.

[0091] Figure 5 This is a graph showing the pollutant removal rate and water production of the disaster emergency water purification bag of Embodiment 1 of the present invention. Figure 5 It can be seen that the disaster emergency water purification bag prepared in Example 1 has a heavy metal rejection rate of Pb. 2+ / Cd 2+ >99.5%, with a 100% E. coli rejection rate, and can produce 1200 mL of water after a single use of 2 hours.

[0092] Figure 6 This is a graph showing the pollutant removal rate and water production of the outdoor hiking-type water purification bag of Embodiment 2 of the present invention. Figure 6 It can be seen that the outdoor hiking-type water purification bag of Example 2 has an organic micro-pollution rejection rate of >99.8%, a parasite rejection rate of 100%, and can produce 1800mL of water after a single use of 2 hours.

[0093] Figure 7 This is a graph showing the contaminant removal rate and water production of the downhole operation-type water purification bag in Embodiment 3 of the present invention. Figure 7 It can be seen that the downhole operation type water purification bag of Example 3 has a heavy metal ion rejection rate of >99.7% and can produce 1400mL of water in 2 hours of single use.

[0094] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended scope of protection is intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of this invention.

[0095] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of protection of this invention and its equivalents, this invention also intends to include these modifications and variations.

Claims

1. A hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, characterized in that, The antibacterial water purification bag includes a membrane bag, which is formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes together. The hydrophilic TA@MOF-based forward osmosis membrane includes a base membrane layer, a sandwich membrane layer, and a dense active layer from the inside to the outside of the water purification bag. The base membrane layer is a polyacrylonitrile matrix membrane layer, which is doped with glucosamine at a doping amount of 4wt.%~6wt.%. The sandwich membrane layer is a TA@MOF particle layer formed by tannic acid-modified MOF. The dense active layer is an active layer formed by chitosan-modified polyamide.

2. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 1, characterized in that, The thickness of the base film layer is 50μm~150μm, the thickness of the interlayer film layer is 1μm~20μm, and the thickness of the dense active layer is 50nm~100nm.

3. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 1, characterized in that, A method for preparing a polyacrylonitrile matrix membrane includes the following steps: Aminoglucose and a pore-forming agent are added to a polyacrylonitrile solution for degassing to form a casting solution. The casting solution was coated onto the substrate by immersion precipitation and then dried to obtain a polyacrylonitrile matrix film.

4. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 3, characterized in that, The casting solution is composed of the following components by mass percentage: 8%~9% polyacrylonitrile, 4%~6% glucosamine, 83% mixed solvent, and 3%~4% pore-forming agent, totaling 100%; wherein, the mixed solvent is composed of the following components by mass percentage: 70%~80% N-methylpyrrolidone, 15%~25% dimethylformamide, and 3%~10% water, totaling 100%; the pore-forming agent is a mixture of polyethylene glycol and sodium chloride in a mass ratio of 1.5~3:

1.

5. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 1, characterized in that, The preparation method of hydrophilic TA@MOF-based forward osmosis membrane includes the following steps: The TA@MOF dispersion was filtered onto the surface of the base film layer by vacuum filtration, so that the TA@MOF particles were dispersed on the surface of the base film layer to form a TA@MOF sandwich layer. Using interfacial polymerization, the TA@MOF membrane layer is sequentially immersed in an aqueous phase containing an aromatic diamine and an organic phase containing trichlorobenzoyl chloride monomers, followed by heat treatment to form a polyamide membrane layer. Subsequently, the polyamide membrane layer is activated to obtain an activated polyamide membrane layer. The activated polyamide membrane layer is then immersed in a chitosan solution, allowing chitosan to be adsorbed onto the surface of the polyamide membrane, forming a chitosan-adsorbed polyamide membrane. The chitosan-adsorbed polyamide membrane is then dissolved in a glutaraldehyde solution, resulting in a crosslinking reaction that forms an active layer of chitosan-modified polyamide on the surface of the TA@MOF membrane layer, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

6. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 5, characterized in that, The vacuum filtration pressure is 0.01 MPa to 0.1 MPa; the filtration time is 0.5 min to 10 min; and the concentration of the TA@MOF dispersion is 0.1 mg / mL to 5 mg / mL.

7. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 5, characterized in that, The aromatic diamine is m-phenylenediamine; the trichlorobenzoyl chloride monomer is trimesoyl chloride; the activation treatment involves soaking in an acidic solution for 5 to 15 minutes, the acidic solution being hydrochloric acid with a concentration of 0.01 mol / L to 0.1 mol / L; the chitosan solution contains 0.1 wt.% to 1.5 wt.% chitosan by mass, and the solvent is an acetic acid solution with a mass fraction of 0.5 wt.%; the soaking time is 15 to 60 minutes; the glutaraldehyde solution concentration is 0.05 wt.% to 0.5 wt.%; and the crosslinking time is 10 to 60 minutes.

8. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 5, characterized in that, The preparation method of TA@MOF dispersion includes the following steps: Metal ions and ligands are dissolved in a solvent, tannic acid is added, and the mixture is reacted at 25℃~120℃ to obtain TA@MOF particles; TA@MOF particles were dispersed in water and sonicated to obtain a TA@MOF dispersion.

9. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 8, characterized in that, The ligands are imidazole or carboxyl ligands, and the metal ions are transition metal elements; the molar ratio of tannic acid to metal ions is 0.05~0.5:1, and the molar ratio of tannic acid to ligands is 0.05~0.5:1; the reaction time is 1h~24h.

10. A method for preparing a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to any one of claims 1 to 9, characterized in that, Includes the following steps: Two hydrophilic TA@MOF-based forward osmosis membranes are bonded together, and the bonded ends are heat-sealed to form a membrane bag with an opening. The dense active layer of the TA@MOF-based forward osmosis membrane is located on the outside. By injecting an extractant into the membrane bag through the opening and then sealing the opening, a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag is obtained.

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