Hydrophilic TA (at) MOF-based forward osmosis antibacterial water purification bag and preparation method thereof

Abstract

The invention belongs to the field of water quality purification, and particularly relates to a hydrophilic TA (at) MOF-based forward osmosis antibacterial water purification bag and a preparation method thereof. The antibacterial water purification bag comprises a membrane bag, wherein the membrane bag is formed by attaching and sealing two hydrophilic TA (at) MOF-based forward osmosis membranes; the hydrophilic TA (at) MOF-based forward osmosis membrane comprises a base membrane layer, a sandwich membrane layer and a compact active layer from inside to outside along the water purification bag. The base membrane layer is a polyacrylonitrile matrix membrane layer, and glucosamine is doped in the polyacrylonitrile matrix membrane layer, so that the hydrophilicity can be improved; the film clamping layer is a TA (at) MOF particle layer, selective interception and rapid water passing are achieved, the compact active layer is a modified polyamide active layer, and the antibacterial property and the heavy metal interception capacity can be enhanced. The forward osmosis antibacterial water purification bag is simple in structure, high in portability, capable of being quickly started and effectively purifying water, and suitable for being used in various emergency environments.

Description

Technical Field

[0001] The present invention belongs to the field of water purification, and in particular relates to a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag and a preparation method thereof. Background Art

[0002] In special environments such as disaster response, aviation, field operations, and hiking expeditions, the lack of safe and convenient drinking water sources is a key factor hindering emergency response efficiency and protecting people's lives. Therefore, developing emergency water purification devices that are portable, efficient, and environmentally adaptable is of great practical significance. Current water purification technologies primarily rely on ultrafiltration or reverse osmosis, and these devices have certain drawbacks. For example, pump-type water purifiers (LifeStrawGo, MSR Guardian) are expensive, energy-intensive, and poorly treat turbid water. Ultrafiltration water purifiers (Sawyer mini) require pressure, consume high energy, and are bulky and difficult to transport. Compared to traditional membrane methods such as ultrafiltration, forward osmosis (FO) is a membrane separation process that uses a high-osmotic pressure draw fluid as the driving force to transfer water molecules from low-concentration raw water through a semipermeable membrane to a high-concentration solution. FO offers advantages such as zero energy consumption, ease of operation, and high purification accuracy, making it particularly suitable for emergency scenarios with limited power and complex water quality.

[0003] However, existing forward osmosis water purification devices suffer from systemic shortcomings in structural design, membrane fouling tolerance, and stability in extreme environments. This makes them unable to meet the core requirements of "ready-to-use, qualified purification, and lightweight" in emergency scenarios, limiting their widespread application in emergency situations. Therefore, the question is how to develop a portable emergency water purification system that is simple in structure, lightweight, easy to carry, and has excellent water purification performance to meet the rapid response needs for drinking water safety in emergencies. Summary of the Invention

[0004] In order to solve the above-mentioned problems, the present invention provides a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag and a preparation method thereof. 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 is composed of a base membrane layer, an interlayer layer and a dense active layer. The base membrane layer is a polyacrylonitrile matrix membrane doped with glucosamine to improve hydrophilicity; the interlayer layer is a TA@MOF particle layer formed by tannic acid modified and coated MOF to achieve selective interception and rapid water flow; the dense active layer is an active layer formed by chitosan-modified polyamide, which has antibacterial and heavy metal interception functions. The antibacterial water purification bag has a simple structure, is easy to carry, has excellent hydrophilicity, strong pollution resistance, good antibacterial properties and fast startup, and is suitable for drinking water purification in harsh emergency environments.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The object of the present invention is to provide a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, which includes a membrane bag, which is formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes; the hydrophilic TA@MOF-based forward osmosis membrane includes a base membrane layer, an interlayer layer and a dense active layer along the water purification bag from the inside to the outside; the base membrane layer is a polyacrylonitrile matrix membrane layer, and the polyacrylonitrile matrix membrane layer is doped with glucosamine, and the doping amount of glucosamine is 4wt.%~6wt.%, the interlayer layer is a TA@MOF particle layer formed by tannic acid modified and coated MOF, and the dense active layer is an active layer formed by chitosan modified polyamide.

[0006] In a preferred embodiment of the present invention, the thickness of the base film layer is 50 μm to 150 μm, the thickness of the interlayer is 1 μm to 20 μm, and the thickness of the dense active layer is 50 nm to 100 nm.

[0007] In a preferred embodiment of the present invention, the method for preparing the polyacrylonitrile matrix membrane comprises the following steps: S1. Adding glucosamine and a porogen to the polyacrylonitrile solution for degassing to form a film casting solution.

[0008] S2. The casting solution is coated on the substrate by immersion precipitation, and dried to obtain a polyacrylonitrile matrix membrane.

[0009] In a preferred embodiment of the present invention, the casting solution is composed of the following components in mass percentage: 8% to 9% polyacrylonitrile, 4% to 6% glucosamine, 83% mixed solvent and 3% to 4% porogen, totaling 100%; wherein the mixed solvent is composed of the following components in mass percentage: 70% to 80% N-methylpyrrolidone, 15% to 25% dimethylformamide and 3% to 10% water, totaling 100%; the porogen is a mixture of polyethylene glycol and sodium chloride in a mass ratio of 1.5 to 3:1.

[0010] In a preferred embodiment of the present invention, the method for preparing a hydrophilic TA@MOF-based forward osmosis membrane comprises the following steps: S1. Filter the TA@MOF particle dispersion 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 interlayer.

[0011] S2. Using interfacial polymerization, the TA@MOF interlayer is sequentially immersed in an aqueous phase containing aromatic diamine and an organic phase containing trichlorobenzoyl chloride-type acyl chloride monomers, and heat-treated to form a polyamide membrane layer; the polyamide membrane layer is then activated to obtain an activated polyamide membrane layer; the activated polyamide membrane layer is immersed in a chitosan solution to allow chitosan to adsorb on the surface of the polyamide membrane to form a chitosan-adsorbed polyamide membrane; the chitosan-adsorbed polyamide membrane is dissolved in a glutaraldehyde solution to cause a cross-linking reaction, so that an active layer formed by chitosan-modified polyamide is formed on the surface of the TA@MOF interlayer, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0012] 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.

[0013] In a preferred embodiment of the present invention, the aromatic diamine is m-phenylenediamine; the trichlorobenzoyl chloride-type acyl chloride monomer is trimesoyl chloride; the activation treatment is soaking in an acidic solution for 5 min to 15 min, the acidic solution is hydrochloric acid with a concentration of 0.01 mol / L to 0.1 mol / L; the mass fraction of chitosan in the chitosan solution is 0.1 wt.% to 1.5 wt.%, 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 concentration of the glutaraldehyde solution is 0.05 wt.% to 0.5 wt.%; and the crosslinking time is 10 min to 60 min.

[0014] In a preferred embodiment of the present invention, the method for preparing a TA@MOF dispersion comprises the following steps: S1. Dissolve the metal ions and ligands in a solvent, add tannic acid, and react at 25°C~120°C to obtain TA@MOF particles.

[0015] S2. Disperse the TA@MOF particles in water and ultrasonicate to obtain a TA@MOF dispersion.

[0016] In a preferred embodiment of the present invention, the ligand is an imidazole ligand or a carboxyl ligand, the metal ion is a transition metal element; the molar ratio of tannic acid to metal ion is 0.05~0.5:1, and the molar ratio of tannic acid to ligand is 0.05~0.5:1; and the reaction time is 1h~24h.

[0017] 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: S1. Laminating two hydrophilic TA@MOF-based forward osmosis membranes, heat-sealing the laminating ends to form a membrane bag with an opening, and the dense active layer of the TA@MOF-based forward osmosis membrane is located on the outside.

[0018] S2. Inject an extractant into the membrane bag through the opening, seal the opening, and obtain a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, which includes a membrane bag. The membrane bag is formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes. The hydrophilic TA@MOF-based forward osmosis membrane is composed of a base membrane layer, an interlayer layer and a dense active layer. The base membrane layer is a polyacrylonitrile matrix membrane layer, which provides mechanical support as the bottom layer of the forward osmosis membrane. Its doping with aminoglucosamine can enhance hydrophilicity, reduce the interfacial contact angle, reduce internal concentration polarization, and enhance the bonding force with other membrane layers to avoid delamination and shedding. The interlayer is a TA@MOF particle layer formed by tannic acid modified and coated MOF. TA@MOF particles can construct secondary selective channels to achieve selective interception of large molecules or pollutants, rapid water and small ions, and improve interface roughness. At the same time, TA modification enhances hydrophilicity, and phenolic hydroxyl groups provide metal complexing ability, enhancing antibacterial and anti-fouling properties. The dense active layer is an active layer formed by chitosan modified polyamide, which has stable antibacterial function and the ability to intercept heavy metal ions and harmful substances. The hydrophilicity is improved by chitosan adsorption and glutaraldehyde cross-linking modification, accelerating the contact and dissolution of the drying extractant with water, quickly forming a high osmotic pressure difference, and shortening the waiting time for water purification startup. The forward osmosis membrane structure has high water permeability, high selectivity, high pollution resistance and antibacterial properties, and is suitable for drinking water purification in a variety of harsh emergency environments. The antibacterial water purification bag has a simple structure, strong portability, high water purification efficiency, pollution resistance, antibacterial and heavy metal retention functions, and effectively shortens the startup time. It is suitable for use in a variety of emergency environments and significantly improves user experience and drinking water safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the antibacterial water purification bag made by the present invention.

[0021] Figure 2 This is a physical picture of the antibacterial water purification bag made by the present invention.

[0022] Figure 3 This is a test diagram of the contact angle of the forward osmosis membrane of Examples 1 to 3 of the present invention.

[0023] Figure 4 This is a contact angle test diagram of the forward osmosis membrane of Comparative Example 1 of the present invention.

[0024] Figure 5 This is a graph showing the pollutant removal rate and water production of the disaster emergency water purification bag according to Example 1 of the present invention.

[0025] Figure 6 This is a graph showing the pollutant removal rate and water production of the outdoor hiking water purification bag according to Example 2 of the present invention.

[0026] Figure 7 This is a graph showing the pollutant removal rate and water production of the underground operation type water purification bag of Example 3 of the present invention. DETAILED DESCRIPTION

[0027] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods. In the present invention, the English abbreviation of polyacrylonitrile is PAN, the English abbreviation of N-methylpyrrolidone is NMP, the English abbreviation of tannic acid is TA, the English abbreviation of dimethylformamide is DMF, and the English abbreviation of polyethylene glycol is PEG-2000.

[0029] Existing forward osmosis water purification devices suffer from systemic shortcomings in structural design, membrane fouling tolerance, and stability in extreme environments. This makes them unable to meet the core requirements of "ready-to-use, qualified purification, and lightweight" in emergency scenarios, limiting their widespread application in this field. Therefore, the challenge remains to develop a portable emergency water purification system that is simple in structure, lightweight, easy to carry, and offers excellent water purification performance to meet the rapid response needs for drinking water safety in emergencies.

[0030] Based on this, on the one hand, the present invention provides a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag, which includes a membrane bag, which is formed by bonding and sealing two hydrophilic TA@MOF-based forward osmosis membranes; the hydrophilic TA@MOF-based forward osmosis membrane includes a base membrane layer, an interlayer layer and a dense active layer from bottom to top along the thickness direction; the base membrane layer is a polyacrylonitrile matrix membrane layer, and the polyacrylonitrile matrix membrane layer is doped with glucosamine, and the doping amount of glucosamine is 4wt.%~6wt.%, the interlayer layer is a TA@MOF particle layer formed by tannic acid modified and coated MOF, and the dense active layer is an active layer formed by chitosan modified polyamide.

[0031] It should be noted that the reaction principles and functions of each membrane layer in the hydrophilic TA@MOF-based forward osmosis membrane are as follows: (1) Principle of base membrane reaction: The mixed solvent diffuses outward rapidly, and the non-solvent (water) enters the membrane liquid, causing phase separation. The porogen dissolves in water to form a porous structure. The doped glucosamine is evenly dispersed in the membrane matrix, and its hydrophilic groups are solidified on the inner wall of the base membrane. Function: The base membrane serves as the bottom layer of the forward osmosis membrane and provides mechanical support. The purpose of doping glucosamine containing amino and hydroxyl groups is to increase the hydrophilicity of the base membrane, reduce the interfacial contact angle, and help reduce internal concentration polarization. At the same time, it improves the interfacial bonding force. The hydrophilic groups strengthen the bonding force with the middle TA@MOF layer and the upper polyamide active layer, preventing delamination.

[0032] (2) Interlayer reaction principle: TA is adsorbed on the MOF surface through hydrogen bonding and coordination to form a surface coating. TA modification makes the particles hydrophilic and provides metal complexing ability through phenolic hydroxyl groups. Function: The intermediate interlayer TA@MOF first constructs a secondary selective channel. The ordered nanopores of MOF selectively intercept large molecules or pollutants, allowing water and small ions to pass 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 and provides metal complexing ability through phenolic hydroxyl groups, enhancing antibacterial and anti-fouling properties.

[0033] (3) Dense active layer reaction principle: 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 between the two phases to form 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 has the function of promoting the rapid penetration of water molecules. The high hydrophilicity and porous structure of the gel coating increase the contact rate between the dry extractant powder in the water purification bag and water, accelerate the dissolution process, and quickly form a high osmotic pressure difference, thereby significantly shortening the waiting time for the water purification bag to start.

[0034] The forward osmosis membrane structure has high water permeability, high selectivity, high pollution resistance and antibacterial properties, and is suitable for drinking water purification in a variety of harsh emergency environments.

[0035] The thickness of the base membrane layer is 50 μm to 150 μm, the thickness of the interlayer is 1 μm to 20 μm, and the thickness of the dense active layer is 50 nm to 100 nm. During the preparation of forward osmosis composite membranes, membrane thickness has a significant impact on membrane structure and performance: when the base membrane is too thick, the solvent-nonsolvent exchange rate slows down, and a dense structure is easily formed. While this provides good 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 internal concentration polarization is weak, which is beneficial for improving water flux and selectivity. However, it is easy to produce penetrating macropores or collapse during the phase inversion process, making it difficult to obtain a uniform, defect-free active layer during interfacial polymerization, and the mechanical strength during membrane formation and use is insufficient. In order to take into account both flux and strength, the support layer thickness is usually controlled in the range of 50μm~150μm in actual preparation. By optimizing the casting liquid concentration, scraping film thickness and phase conversion conditions, a thin and porous base membrane, a uniform intermediate functional layer and an ultra-thin and dense polyamide active layer are achieved, thereby obtaining a forward osmosis membrane with high flux, high selectivity and high stability.

[0036] The polyacrylonitrile matrix membrane preparation method comprises the following steps: adding glucosamine and a porogen to a polyacrylonitrile solution, performing a degassing treatment, and forming a casting solution; coating the casting solution on a substrate using an immersion precipitation method, and drying to obtain the polyacrylonitrile matrix membrane. The matrix membrane prepared by this method has good hydrophilicity and a pore structure.

[0037] In a specific embodiment, the polyacrylonitrile solution is formed by adding PAN powder into a mixed solvent, stirring at 60°C for 4 hours to 8 hours to completely dissolve it, and then cooling to 40°C.

[0038] The casting solution is composed of the following components in mass percentage: 8% to 9% polyacrylonitrile, 4% to 6% glucosamine, 83% mixed solvent and 3% to 4% porogen, which total 100%; wherein the mixed solvent is composed of the following components in mass percentage: 70% to 80% N-methylpyrrolidone, 15% to 25% dimethylformamide and 3% to 10% water, which total 100%; the porogen is a mixture of polyethylene glycol and sodium chloride in a mass ratio of 1.5 to 3:1.

[0039] The method for preparing the hydrophilic TA@MOF-based forward osmosis membrane comprises the following steps: S1. Filter the TA@MOF particle dispersion 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 interlayer.

[0040] S2. Using interfacial polymerization, the TA@MOF interlayer is sequentially immersed in an aqueous phase containing aromatic diamine and an organic phase containing trichlorobenzoyl chloride-type acyl chloride monomers, and heat-treated to form a polyamide membrane layer; the polyamide membrane layer is then activated to obtain an activated polyamide membrane layer; the activated polyamide membrane layer is immersed in a chitosan solution to allow chitosan to adsorb on the surface of the polyamide membrane to form a chitosan-adsorbed polyamide membrane; the chitosan-adsorbed polyamide membrane is dissolved in a glutaraldehyde solution to cause a cross-linking reaction, so that an active layer formed by chitosan-modified polyamide is formed on the surface of the TA@MOF interlayer, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0041] 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 the appropriate thickness of the interlayer and the uniformity of the particles.

[0042] The method for preparing a TA@MOF dispersion comprises the following steps: dissolving a metal ion and a ligand in a solvent, adding tannic acid, and reacting at 25°C to 120°C to obtain TA@MOF particles; dispersing the TA@MOF particles in water and sonicating to obtain a TA@MOF dispersion. The ligand is not limited to imidazole or carboxyl ligands, and the metal ion is a transition metal element; the molar ratio of tannic acid to metal ion or ligand is 0.05 to 0.5:1; and the reaction time is 1 to 24 hours. The concentration of the TA@MOF dispersion is 0.1 mg / mL to 5 mg / mL. Tannic acid is used as a functionalizing agent, and by adjusting the molar ratio of tannic acid to metal ion or ligand, effective doping or surface coating of tannic acid during MOF nucleation and growth is achieved. Reaction conditions, including temperature, reaction time, pH, and stirring rate, are then adjusted to obtain two-dimensional TA@MOF particles with uniform morphology and uniform tannic acid distribution.

[0043] The aromatic diamine includes but is not limited to m-phenylenediamine; the trichlorobenzoyl chloride type acyl chloride monomer includes but is not limited to trimesoyl chloride.

[0044] The activation treatment includes but is not limited to: soaking in an acidic solution for 5 minutes 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.

[0045] The chitosan solution contains chitosan at a mass fraction of 0.1 wt.% to 1.5 wt.%, and the solvent is an acetic acid solution at a mass fraction of 0.5 wt.%. The polyamide membrane is immersed in the chitosan solution for 15 to 60 minutes to allow the chitosan to fully adsorb on the membrane surface.

[0046] The glutaraldehyde solution has a concentration of 0.05% to 0.5% by weight, and a crosslinking time of 10 to 60 minutes. This allows the aldehyde groups of glutaraldehyde to crosslink with the amino groups of chitosan, forming a stable network structure. After the crosslinking reaction, the modified polyamide active layer must be washed with water to remove unreacted substances and then dried at below 50°C to obtain a modified polyamide active layer with stable antibacterial properties and enhanced retention of heavy metal ions and harmful substances.

[0047] The antibacterial water purification bag designed by the present invention has a simple structure, strong portability, high water purification efficiency, pollution resistance, antibacterial and heavy metal retention functions, and effectively shortens the startup time. It is suitable for use in a variety of emergency environments and significantly improves user experience and drinking water safety.

[0048] 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: S1. Laminating two hydrophilic TA@MOF-based forward osmosis membranes, heat-sealing the laminating ends to form a membrane bag with an opening, and the dense active layer of the TA@MOF-based forward osmosis membrane is located on the outside.

[0049] S2. Inject an extractant into the membrane bag through the opening, seal the opening, and obtain a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag.

[0050] The hydrophilic TA@MOF-based forward osmosis membrane needs to be pretreated, and the pretreatment steps are to dry the hydrophilic TA@MOF-based forward osmosis membrane at room temperature, soak it in a propylene glycol aqueous solution with a mass fraction of 40wt.%, and dry it at room temperature after 4h~6h. In the specific use process, since the hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag contacts water, the water penetrates into the membrane bag. Therefore, a waterproof packaging layer is provided outside the membrane bag. The waterproof packaging layer can be a plastic sealing bag prefabricated with a PA / PE composite film, thereby obtaining an antibacterial water purification bag with a double-layer protective structure. During use, the packaging layer is removed and placed in water to absorb water. The structure of the antibacterial water purification bag with a double-layer protective structure is as follows Figure 1 As shown, it consists of a plastic bag 1, a film bag 2, an extracting agent 3, a drinking water port 4 and a water purification tank 5.

[0051] The extractants have different components depending on the application scenario. In specific examples, a lemon energy extractant composed of glucose, citric acid, and honey powder is suitable for disaster response; an anti-fatigue extractant composed of caffeine, taurine, and fructose is suitable for outdoor hiking; and an electrolyte extractant composed of sodium citrate, potassium chloride, and glycine is suitable for underground operations.

[0052] The following is further explained through specific examples.

[0053] Example 1 A method for preparing a disaster emergency hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag comprises the following steps: S1. Dissolve 8g of PAN in 83g of a mixed solvent consisting of 75% NMP, 20% DMF, and 5% water. Stir at 60°C for 5h until completely dissolved to obtain a PAN solution. Cool the PAN solution to 40°C, add 6g of glucosamine, and stir for 1h. Then, add 1.5g of PEG-2000 and 1.5g of NaCl particles, stir and disperse, and let stand for 24h to degas. This solution is then applied to a nonwoven fabric substrate using an immersion precipitation method. The solution is then immersed in a 25°C pure water bath for phase inversion for 10s. The solution is then washed with water and dried at 40°C to obtain a hydrophilic polyacrylonitrile matrix membrane, i.e., the base membrane.

[0054] 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 hours. Centrifuge and wash to obtain TA@ZIF-8 particles. Disperse 20 mg of TA@ZIF-8 particles in 2 mg / mL deionized water and ultrasonicate for 30 minutes. Vacuum filter the surface of the base membrane at 0.06 MPa for 5 minutes to form a uniform interlayer.

[0055] S3. Immerse the interlayer in a 2 wt.% aqueous solution of m-phenylenediamine for 60 seconds, remove the excess solution and drain. Then, immerse it in a 0.2 wt.% hexane solution of trimesoyl chloride for 1 minute, remove the excess solution, and heat treat it 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 transferring it to a 0.2 wt.% glutaraldehyde solution for cross-linking reaction for 20 minutes. Wash with water and dry at 45°C to obtain an active layer formed by chitosan-modified polyamide, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0056] S4. Take two pieces of hydrophilic TA@MOF-based forward osmosis membranes prepared in S3. The size of a single membrane is 10cm×15cm. Dry them at room temperature and soak them in a 40wt.% propylene glycol aqueous solution. After 6 hours of drying at room temperature, a pretreated hydrophilic TA@MOF-based forward osmosis membrane is obtained. The active layer of the pretreated hydrophilic TA@MOF-based forward osmosis membrane is facing outward. After the three sides of the two membranes are heat-sealed with a hot press sealing machine, a forward osmosis membrane bag is formed. The extractant is a dry lemon energy-type extractant, which is a mixture of 30g glucose, 5g citric acid and 5g honey powder. Subsequently, the membrane bag is sealed with a hot press sealing machine. Finally, the membrane bag is placed in a 20cm×25cm plastic bag prefabricated with a PA / PE composite film, thereby obtaining an antibacterial water purification bag with a double-layer protective structure, that is, a disaster emergency water purification bag, such as Figure 2 shown.

[0057] The effective area of ​​the disaster emergency water bag is 300cm 2 Disaster emergency water bags are suitable for river water and surface water in flooded areas under disaster emergency scenarios. Among them, the number of Vibrio cholerae in the water body is greater than 10 6 CFU / mL, Pb in heavy metals 2+ / Cd 2+ ≤0.5mg / L, suspended matter content is 50NTU~200NTU.

[0058] Example 2 A method for preparing an outdoor hiking-type hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag comprises the following steps: S1. Dissolve 9g of PAN in 83g of a mixed solvent consisting of 75% NMP, 20% DMF, and 5% water. Stir at 60°C for 8h until completely dissolved to obtain a PAN solution. Cool the PAN solution to 40°C, add 4g of glucosamine, and stir for 1h. Then, add 2.5g of PEG-2000 and 1.5g of NaCl particles, stir and disperse, and let stand for 24h to degas. This solution is then applied to a nonwoven fabric substrate using an immersion precipitation method. The solution is then immersed in a 25°C pure water bath for phase inversion for 10s. The solution is then washed with water and dried at 40°C to obtain a hydrophilic polyacrylonitrile matrix membrane, the base membrane.

[0059] 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 hours. Centrifuge and wash to obtain TA@ZIF-8 particles. Disperse 30 mg of TA@ZIF-8 particles in 2 mg / mL deionized water and ultrasonicate for 30 minutes. Vacuum filter the surface of the base film at 0.03 MPa for 5 minutes to form a uniform interlayer.

[0060] S3. Immerse the interlayer in a 1.5wt% aqueous solution of m-phenylenediamine for 90 seconds, remove the excess solution and drain, then immerse it in a 0.15wt% n-hexane solution of trimesoyl chloride for 1 minute, remove the excess solution, and heat treat for 8 minutes to form a polyamide layer. Activate the surface of the polyamide layer with a 0.05mol / L HCl solution for 10 minutes; then immerse the polyamide layer in a 1.5wt% chitosan solution for 30 minutes. The chitosan solution is obtained by dissolving chitosan in a 0.5wt% acetic acid solution, and then transferred to a 0.2wt% glutaraldehyde solution for cross-linking reaction for 15 minutes; wash with water and dry at 45°C to obtain an active layer formed by chitosan-modified polyamide, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0061] S4. Take two hydrophilic TA@MOF-based forward osmosis membranes prepared in S3, each measuring 10 cm × 15 cm. Air-dry them at room temperature and soak them in a 40 wt.% aqueous glycerol solution. After 6 hours of drying at room temperature, obtain a pretreated hydrophilic TA@MOF-based forward osmosis membrane. Place the pretreated hydrophilic TA@MOF-based forward osmosis membrane with the active layer facing outward. Heat-seal the two membranes on three sides using a hot press to form a forward osmosis membrane bag. Inject an extractant from the open end. The extractant is a dry, anti-fatigue functional extractant composed of 2g caffeine, 3g taurine, and 35g fructose. Then, seal the edges of the membrane bag using a hot press. Finally, place the membrane bag in a 20 cm × 25 cm plastic bag prefabricated from a PA / PE composite film, thereby obtaining an antibacterial water purification bag with a double-layer protective structure, i.e., an outdoor hiking-grade water purification bag.

[0062] The effective area of ​​the outdoor hiking water bag is 300cm 2 The outdoor hiking water bag is suitable for mountain streams and plateau lakes in outdoor hiking scenes. Among them, the Cryptosporidium oocysts in the water body are >10 3 / L, pesticides in organic micro-pollution ≤0.1mg / L.

[0063] Example 3 A method for preparing a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag for underground operation comprises the following steps: S1. Dissolve 9g of PAN in 83g of a mixed solvent consisting of 75% NMP, 20% DMF, and 5% water. Stir at 60°C for 8h until completely dissolved to obtain a PAN solution. Cool the PAN solution to 40°C, add 4g of glucosamine, and stir for 1h. Then, add 2.5g of PEG-2000 and 1.5g of NaCl particles, stir and disperse, and let stand for 24h to degas. This solution is then applied to a nonwoven fabric substrate using an immersion precipitation method. The solution is then immersed in a 25°C pure water bath for phase inversion for 10s. The solution is then washed with water and dried at 40°C to obtain a hydrophilic polyacrylonitrile matrix membrane, the base membrane.

[0064] 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. Centrifuge and wash to obtain TA@ZIF-8 particles. Disperse 15 mg of TA@ZIF-8 particles in 2 mg / mL deionized water and ultrasonicate for 30 min. Vacuum filter the surface of the base film at 0.06 MPa for 10 min to form a uniform interlayer.

[0065] S3. Immerse the interlayer in a 2 wt.% aqueous solution of m-phenylenediamine for 120 seconds, remove the excess solution and drain. Then, immerse it in a 0.1 wt.% hexane solution of trimesoyl chloride for 1 minute, remove the excess solution, and heat treat it for 5 minutes to form a polyamide layer. Activate the surface of the polyamide layer with a 0.1 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 transferring it to a 0.2 wt.% glutaraldehyde solution for cross-linking reaction for 15 minutes. Wash with water and dry at 45°C to obtain an active layer formed by chitosan-modified polyamide, thereby obtaining a hydrophilic TA@MOF-based forward osmosis membrane.

[0066] S4. Take two hydrophilic TA@MOF-based forward osmosis membranes prepared in S3, each measuring 10 cm × 15 cm. Air-dry at room temperature and soak in a 40 wt.% aqueous glycerol solution. After 6 hours, dry at room temperature to obtain a pretreated hydrophilic TA@MOF-based forward osmosis membrane. Place the pretreated hydrophilic TA@MOF-based forward osmosis membrane with the active layer facing outward. Heat-seal the two membranes on three sides using a hot press to form a forward osmosis membrane bag. Inject an 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 membrane bag with a hot press and place it in a 20 cm × 25 cm plastic bag prefabricated from a PA / PE composite film. This creates an antibacterial water purification bag with a double-layer protective structure, i.e., a water purification bag for underground operations.

[0067] The effective area of ​​the underground operation water bag is 300cm 2 The water quality suitable for underground operation water bags is mine water and rock seepage in the event of an underground operation accident. Among them, the water body mainly contains heavy metal ions such as iron, manganese, lead, zinc and copper.

[0068] Comparative Example 1 The difference from Example 1 is that unmodified ZIF-8 is used instead of TA@ZIF-8 particles.

[0069] The forward osmosis membranes in Examples 1 to 3 and Comparative Example 1 were subjected to performance tests. The hydrophilicity of the membrane surface was characterized by measuring the contact angle by adding a deionized water droplet in a static state using a contact angle meter. The water flux of the membrane was measured using a self-built forward osmosis test device, which mainly consists of a feed side and an extraction liquid, a flat membrane tank, a circulation system, and a measurement and recording system. The extraction liquid volume that changes with time is recorded and calculated based on the unit time and effective membrane area. The water flux calculation formula is:

[0070] .

[0071] Where ΔV is the volume change of the drawn liquid chamber (L), A is the effective membrane area (m 2 ), Δt is the test time (h).

[0072] Figure 3 This is a test diagram of the contact angle of the forward osmosis membrane of Examples 1 to 3 of the present invention. Figure 4 This is a test diagram of the contact angle of the forward osmosis membrane of Comparative Example 1 of the present invention. Figure 3 and Figure 4As can be seen, the hydrophilic contact angle of the forward osmosis membrane of Example 1 is 45.1°, the hydrophilic contact angle of the forward osmosis membrane of Example 2 is 43.6°, the hydrophilic contact angle of the forward osmosis membrane of Example 3 is 44.7°, and the contact angle of the forward osmosis membrane of Comparative Example 1 is 65.2°. This indicates that the forward osmosis membrane of Comparative Example 1, which is not modified with tannic acid, has a significantly higher contact angle than the TA@MOF-based forward osmosis membranes of Examples 1 to 3, and the hydrophilicity of the membrane surface has decreased.

[0073] The water flux test shows that the pure water flux of the forward osmosis membrane of Example 1 is 28.7 L·m -2 ·h -1 The pure water flux of the forward osmosis membrane of Example 2 is 35.4 L·m -2 ·h -1 The pure water flux of the forward osmosis membrane of Example 3 is 30.6 L·m -2 ·h -1 The pure water flux of the forward osmosis membrane of Comparative Example 1 is 16.8 L·m -2 ·h -1 This indicates that the forward osmosis membrane of Comparative Example 1 that is not modified with tannic acid has a lower water flux and a worse purification efficiency than the TA@MOF-based forward osmosis membranes of Examples 1 to 3.

[0074] The antibacterial water purification bags prepared in Examples 1 to 3 were tested for use. The raw material liquid used in the disaster emergency water purification bag in Example 1 was flood-polluted river water, in which the suspended solids content was 50 NTU and the E. coli content was 10 6 CFU / mL, Pb 2 + The concentration is 0.5 mg / L. The raw material liquid used in the outdoor hiking water purification bag of Example 2 is mountain stream water, wherein the Cryptosporidium content is 1200 / L and the glyphosate pesticide content is 0.08 mg / L. The raw material liquid used in the underground operation water purification bag of Example 3 is mine water, wherein the heavy metal ions are Fe 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, and allow the raw liquid to flow naturally into the bag until the water cavity is full. ② Waiting for penetration: Let it stand for 10 minutes to 30 minutes depending on the water quality, and you can see that the amount of water in the inner bag gradually increases. ③ Use turbidity meter, plate count method and ICP-OES to test the content of water pollutants. Among them, the removal effect of Escherichia coli is evaluated by detecting the number of colony forming units (CFU / mL) in the influent and produced water samples by 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 counting method under a microscope; the removal effect of heavy metal ions is determined by measuring the metal ion concentrations in the influent and produced water by inductively coupled plasma optical emission spectrometry (ICP-OES), and the retention rate is calculated.

[0075] Figure 5 This is a graph showing the pollutant removal rate and water production of the disaster emergency water purification bag of Example 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 retention rate of Pb 2+ / Cd 2+ >99.5%, E. coli retention rate is 100%, and 1200mL of water can be produced after a single use of 2h.

[0076] Figure 6 This is a graph showing the pollutant removal rate and water production of the outdoor walking water purification bag according to Example 2 of the present invention. Figure 6 It can be seen that the outdoor hiking water purification bag of Example 2 has an organic micro-pollutant retention rate of >99.8%, a parasite retention rate of 100%, and can produce 1800 mL of water after a single use of 2 hours.

[0077] Figure 7 This is a graph showing the pollutant removal rate and water production of the underground operation water purification bag of Example 3 of the present invention. Figure 7 It can be seen that the underground operation type water purification bag of Example 3 has a heavy metal ion retention rate of >99.7%, and can produce 1400 mL of water in a single use of 2 hours.

[0078] It should be noted that when the present invention relates to numerical ranges, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes the preferred embodiments. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the attached protection scope is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0079] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the present invention and its equivalents, the present invention is intended to include such changes and modifications.

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; the hydrophilic TA@MOF-based forward osmosis membrane includes a base membrane layer, an interlayer 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, and the polyacrylonitrile matrix membrane layer is doped with glucosamine, and the doping amount of glucosamine is 4wt.%~6wt.%, the interlayer layer is a TA@MOF particle layer formed by tannic acid modified and coated MOF, and 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 50 μm~150 μm, the thickness of the interlayer is 1 μm~20 μm, and the thickness of the dense active layer is 50 nm~100 nm.

3. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 1, characterized in that: The preparation method of the polyacrylonitrile matrix membrane comprises the following steps: adding glucosamine and a porogen to a polyacrylonitrile solution and performing a degassing treatment to form a film casting solution; The casting solution is coated on the substrate by an immersion precipitation method, and the polyacrylonitrile matrix membrane is obtained by drying.

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 in mass percentage: 8% to 9% polyacrylonitrile, 4% to 6% glucosamine, 83% mixed solvent and 3% to 4% porogen, which total 100%; wherein the mixed solvent is composed of the following components in mass percentage: 70% to 80% N-methylpyrrolidone, 15% to 25% dimethylformamide and 3% to 10% water, which total 100%; the porogen is a mixture of polyethylene glycol and sodium chloride in a mass ratio of 1.5 to 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 a hydrophilic TA@MOF-based forward osmosis membrane comprises the following steps: The TA@MOF 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 interlayer. By using interfacial polymerization, the TA@MOF interlayer is sequentially immersed in an aqueous phase containing aromatic diamine and an organic phase containing trichlorobenzoyl chloride-type acyl chloride monomers, and heat-treated to form a polyamide membrane layer; the polyamide membrane layer is then activated to obtain an activated polyamide membrane layer; the activated polyamide membrane layer is immersed in a chitosan solution to allow chitosan to adsorb on the surface of the polyamide membrane to form a chitosan-adsorbed polyamide membrane; the chitosan-adsorbed polyamide membrane is dissolved in a glutaraldehyde solution to cause a cross-linking reaction, thereby forming an active layer formed by chitosan-modified polyamide on the surface of the TA@MOF interlayer, 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 0.01MPa~0.1MPa; the filtration time is 0.5min~10min; the concentration of TA@MOF dispersion is 0.1mg / mL~5mg / 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-type acyl chloride monomer is trimesoyl chloride; the activation treatment is soaking in an acidic solution for 5 minutes to 15 minutes, the acidic solution is hydrochloric acid with a concentration of 0.01 mol / L to 0.1 mol / L; the mass fraction of chitosan in the chitosan solution is 0.1wt.% to 1.5wt.%, and the solvent is an acetic acid solution with a mass fraction of 0.5wt.%; the soaking time is 15 minutes to 60 minutes; the concentration of the glutaraldehyde solution is 0.05wt.% to 0.5wt.%; and the crosslinking time is 10 minutes 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 comprises the following steps: The metal ions and ligands are dissolved in a solvent, tannic acid is added, and the reaction is carried out at 25°C to 120°C to obtain TA@MOF particles. TA@MOF particles were dispersed in water and ultrasonicated to obtain TA@MOF dispersion.

9. The hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag according to claim 8, characterized in that: 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, and the molar ratio of tannic acid to ligand is 0.05-0.5:1; and 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: The following steps are involved: Two hydrophilic TA@MOF-based forward osmosis membranes are laminated together, and the laminating ends are heat-sealed to form a membrane bag with an opening, with the dense active layer of the TA@MOF-based forward osmosis membrane located on the outside; The extractant is injected into the membrane bag through the opening, and the opening is sealed to obtain a hydrophilic TA@MOF-based forward osmosis antibacterial water purification bag.

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