A bio-based antibacterial and antifouling separation membrane enhanced with aloin, its preparation method and application

Abstract

This invention discloses a method for preparing a bio-based antibacterial and antifouling separation membrane enhanced with aloin and its application. The preparation method includes the following steps: mixing a base membrane and a polyamine solution under alkaline conditions and washing; adding an aloin solution and reacting to obtain the aloin-enhanced bio-based antibacterial and antifouling separation membrane. The separation membrane prepared by this method has high throughput while also exhibiting excellent resistance to organic fouling and antibacterial capabilities, effectively mitigating membrane fouling in wastewater treatment and providing excellent antibacterial effects.

Description

Technical Field

[0001] This invention belongs to the technical field of separation membranes, and more specifically, relates to a bio-based antibacterial and antifouling separation membrane reinforced with aloe-emodin, its preparation method, and its application. Background Technology

[0002] Wastewater resource utilization is an important means of solving the water shortage problem. Membrane bioreactors (MBRs) are widely used due to their small footprint, low energy consumption, and simple operation. However, with the development of this technology, pollution has become a major challenge limiting its separation efficiency and service life. During membrane filtration, microbial flocs and biomolecules in the activated sludge mixture can be repelled and adhere to the membrane in the form of a biocake. In addition, hydrophobic organic matter such as proteins, polysaccharides, and humic substances in the feed solution are easily adsorbed and deposited on the membrane surface, causing membrane pore blockage, thereby reducing the membrane's water flux and filtration efficiency.

[0003] Currently, polyvinylidene fluoride (PVDF) membranes are widely used in MBR processes due to their superior chemical stability, thermal stability, and ease of processing. However, commonly used PVDF membranes have strong hydrophobicity, making it difficult to meet antifouling requirements during separation.

[0004] The interaction between different pollutants and membranes involves three processes: contact, adsorption, and accumulation. Passive strategies generally involve altering the membrane surface through grafting, coating, or mixing with hydrophilic materials to weaken the interaction between fouling and the membrane, preventing fouling from adsorbing onto the membrane surface. Active strategies typically involve adding antibacterial substances to the membrane surface to inactivate bacteria and prevent biofilm formation. For example, the paper "Fabrication of ultrafiltration membrane surface with synergistic anti-fouling effect of 'dispersion-impedance' and anti-fouling mechanism of dye" discloses the introduction of hydrophilic chains with different microstructures from melamine and polyethyleneimine onto the membrane surface, significantly weakening the adhesion of fouling to the membrane surface and delaying the formation of irreversible fouling. However, the flux of this type of modified microfiltration membrane continuously decreases, indicating that a single hydrophilic modified surface has limitations and a low antifouling threshold in actual water treatment processes. It is easily covered by high concentrations of pollutants, thus losing its antifouling ability. Furthermore, this hydrophilic microfiltration membrane cannot simultaneously achieve antibacterial and antimicrobial effects; that is, a single hydrophilic modification of the membrane surface cannot achieve good simultaneous resistance to organic matter adhesion, resistance to biofouling, and good water flux in actual biofilm treatment processes. In addition, the comparative document uses dyes as the target for retention, while dyes typically exist in aqueous solutions as large aggregates. Compared to dyes, some bacteria are more easily adsorbed and deposited on the membrane surface.

[0005] Currently, the preparation of antibacterial modified membranes mainly involves the introduction of nanomaterials, the addition of antibacterial polymers, the application of photosensitive dyes, modification with bioenzymes, the introduction of functional carriers, and modification with ionic liquids. These methods can regulate microbial activity, reduce adhesion, and inhibit biofilm formation. The paper "Molecular Sizes and Antibacterial Performance Relationships of Flexible Ionic Liquid Derivatives" discloses flexible fluorescent pyrrolopyrrole dione ionic liquid derivatives (ILDs) of different molecular sizes. ILDs can insert into bacterial membranes, causing instability in the lipid bilayer and further enhancing antibacterial activity. However, some synthetic antibacterial agents suffer from problems such as frequent use and poor environmental friendliness, while some nanomaterials exhibit poor stability in water or pose a risk of spillage toxicity.

[0006] Therefore, it is of great significance to develop a sustainable separation membrane that is resistant to organic matter adhesion, biofouling, and has good water flux, and to establish an antifouling mechanism based on passive defense and active antimicrobial strategies for membrane fouling control. Summary of the Invention

[0007] To address the aforementioned technical problems, the primary objective of this invention is to provide a method for preparing a bio-based antibacterial and antifouling separation membrane enhanced with aloin. The separation membrane prepared by this method not only has high throughput but also significantly improves the membrane's resistance to organic matter adhesion and its antibacterial ability.

[0008] The second objective of this invention is to provide a bio-based antibacterial and anti-fouling separation membrane based on aloe-emodin enhanced by the above preparation method.

[0009] The third objective of this invention is to provide the application of the above-mentioned aloin-enhanced bio-based antibacterial and antifouling separation membrane in water treatment.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0011] A method for preparing a bio-based antibacterial and antifouling separation membrane enhanced with aloe-emodin includes the following steps:

[0012] S1. Mix the base film and polyamine solution under alkaline conditions, and then wash.

[0013] S2. Add aloe-emodin solution and react to obtain the aloe-emodin-enhanced bio-based antibacterial and anti-fouling separation membrane;

[0014] The structural formula of aloin is shown in formula (I) below:

[0015]

[0016] In this invention, the polyamine contains polyamine groups, some of which can undergo hydrolysis with the base membrane under alkaline conditions to form a tightly cross-linked positively charged hydration layer. Subsequently, another part of the amino groups of the polyamine grafted onto the positively charged hydration layer undergoes a nucleophilic ring-opening reaction with the hydroxyl groups on aloin, so that aloin molecules are grafted onto the surface of the positively charged hydration layer. In addition, the π-π interaction (intermolecular interaction force) between the benzene ring and phenolic hydroxyl group in aloin can enable some aloin to be directly deposited on the membrane surface, thereby playing an auxiliary role in improving the surface of the modified hydrophobic membrane.

[0017] In this invention, aloin molecules are rich in hydroxyl groups, exhibiting excellent hydrophilicity. This facilitates the formation of a dense, hydrated protective layer of a certain thickness on the membrane surface, preventing organic pollutants such as proteins from contacting the membrane surface, thereby improving the membrane's separation performance and antifouling properties. Furthermore, the aloin molecule contains aglycones and polyphenol groups, giving it superior redox properties, which are beneficial for interfering with microbial metabolic pathways. Simultaneously, aloin can influence the membrane structure of microorganisms, altering the membrane's fluidity through interaction with microbial membrane lipids, leading to membrane disruption and changes in permeability. This, in turn, reduces microbial attachment and growth on the membrane surface, significantly improving the membrane's antibacterial properties.

[0018] Furthermore, the inventors were surprised to discover through research that, due to the thin hydration layer of the chemical grafting / crosslinking network of aloin molecules, a significant decrease in the flux of the separation membrane was avoided. In other words, the separation membrane provided by this invention still maintains its high flux characteristics after modification.

[0019] The separation membrane prepared by the above-mentioned preparation method of the present invention not only ensures high throughput but also has excellent resistance to organic fouling and antibacterial ability. It can effectively alleviate membrane fouling in wastewater treatment and play an excellent antibacterial role, and has important application value in the field of wastewater resource treatment.

[0020] Preferably, the mass ratio of polyamine to aloin is 1–10:0.02. More preferably, the mass ratio of polyamine to aloin is 2–4:0.02.

[0021] Preferably, the concentration of aloin in the aloin solution is 0.1–5 wt%. More preferably, the concentration of aloin is 0.5–3 wt%; more preferably, the concentration of aloin is 1–2 wt%. Specifically, the concentration of aloin in this invention can be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, etc., or any range formed by the above values, such as 0.5–4 wt%, 1.5 wt%–4.5 wt%, etc., and this invention is not limited thereto.

[0022] Preferably, the concentration of the polyamine in the polyamine solution is 0.01–0.5 wt%. More preferably, the concentration of the polyamine is 0.01–0.05 wt%. Specifically, the concentration of aloin in this invention can be 0.01 wt%, 0.02 wt%, 0.04 wt%, 0.05 wt%, 0.08 wt%, 0.16 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, etc., or any range formed by the above values, such as 0.01–0.04 wt%, 0.02 wt%–0.08 wt%, etc., and this invention is not limited thereto.

[0023] Preferably, the polyamine is selected from one or more of polyethyleneamine, polyethyleneimine, piperazine, diethylenetriamine, and ethylenediamine. More preferably, the polyamine is diethylenetriamine. More specifically, the molecular weight of polyethyleneimine can be 600 to 25,000.

[0024] Preferably, the base film is selected from one or more of polyethersulfone, polyvinylidene fluoride, polyacrylonitrile, polyethylene, polyvinyl chloride, or polytetrafluoroethylene. More preferably, the base film is polyvinylidene fluoride.

[0025] Preferably, in step S2, the pH of the reaction is 8 to 10; more preferably, the pH of the reaction is 8.5 to 9.

[0026] Preferably, the aloin solution further includes a buffer solution. More specifically, the buffer solution can be a buffer solution conventionally used in the art, including but not limited to tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl).

[0027] Preferably, in step S1, the pH of the mixture is 8 to 14; more preferably, the pH of the mixture is 9.5 to 12.5.

[0028] Preferably, in step S1, the mixing time is 1 to 6 hours. More preferably, the mixing time is 2 to 4 hours.

[0029] Preferably, in step S1, the mixing temperature is 50–85°C. More preferably, the mixing temperature is 60–80°C.

[0030] Preferably, before mixing the base film with the polyamine, the surface of the base film can be cleaned with an alcohol solution to remove organic matter from the surface of the base film. More preferably, the alcohol solution can be ethanol, and its volume concentration can be 30-80%.

[0031] Furthermore, this invention seeks protection for the aloe-based bio-based antibacterial and antifouling separation membrane prepared by the above preparation method.

[0032] Preferably, the aloin-enhanced bio-based antibacterial and anti-fouling separation membrane has a porous structure and a thickness of 160–220 nm.

[0033] Furthermore, this invention claims protection for the application of an aloe-based, bio-based antibacterial and antifouling separation membrane reinforced with aloin in water treatment. More specifically, the separation membrane is particularly suitable for applications in water treatment such as reducing microbial adhesion and mitigating organic pollution.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) This invention provides a bio-based antibacterial and antifouling separation membrane enhanced with aloin. Based on passive defense mechanism and active antibacterial mechanism, the low-pollution separation membrane surface is constructed. While ensuring high throughput of the separation membrane, it also has excellent resistance to organic pollution and antibacterial ability, which can effectively alleviate the generation of membrane fouling in sewage treatment and play an excellent antibacterial role.

[0036] (2) In this invention, aloin is firmly fixed on the membrane surface through chemical bonds, and therefore has almost no bactericidal properties that can be dissolved. Introducing it onto the membrane surface allows the modified membrane to inhibit the growth of bacteria on the membrane surface without affecting the functional flora in the treatment system, thus facilitating the normal operation of the wastewater treatment system.

[0037] (3) The materials selected in this invention are green and environmentally friendly, the preparation method is simple and easy, the synthesis conditions are mild, and they are suitable for surface modification of various separation membranes. They have the advantages of low production cost and easy industrialization. Attached Figure Description

[0038] Figure 1 The images show the surface and cross-sectional morphology of the PVDF, PVDF-D, and PVDF-DF films in Example 1.

[0039] Figure 2 This is a schematic diagram of the surface properties of the PVDF, PVDF-D, and PVDF-DF films in Example 1.

[0040] in, Figure 2 (a) is the surface water contact angle of the membrane; Figure 2 (b) represents the surface charge of the membrane.

[0041] Figure 3 The diagram shows the separation performance of the PVDF, PVDF-D, and PVDF-DF membranes in Example 1, and the PVDF-DA (1:1) membrane in Example 2. Figure 3 (a) represents the water flux through the membrane; Figure 3 (b) is the membrane's resistance to organic fouling.

[0042] Figure 4 A comparison of the antibacterial properties of PVDF, PVDF-D, and PVDF-DF membranes.

[0043] Figure 5 SEM images showing the morphological changes of bacteria after co-culturing PVDF, PVDF-D, and PVDF-DF membranes with bacterial culture. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0045] Example 1: Preparation of a bio-based antibacterial and antifouling separation membrane enhanced with aloe-emodin

[0046] (1) Immerse the polyvinylidene fluoride (PVDF) membrane MF010 (PVDF) in 50% (v / v) ethanol for 5 min, rinse it several times with deionized water to obtain the cleaned base membrane, and soak it in deionized water for later use.

[0047] (2) Dissolve 4g of diethylenetriamine (DETA) in deionized water and adjust the pH of the solution to 12.5 with sodium hydroxide; the concentration of DETA after adjustment is 0.02wt% and the volume of the solution is 200mL.

[0048] (3) The base membrane is mixed with the DETA solution prepared in step (2) above, and the base membrane is hydrolyzed under a constant temperature water bath at 75°C. After hydrolysis, it is washed three times with deionized water to remove the amine molecules remaining in the pores of the modified membrane. Then it is soaked in deionized water for 24 hours. The modified membrane obtained is labeled as PVDF-D.

[0049] (4) Dissolve 20 mg of aloin (alloin CAS: 1415-73-2, its structural formula is shown in formula (I) below) in 50 mM Tris HCl buffer solution, and adjust the pH of the solution to 8.5 with hydrochloric acid (alloin concentration is 1 wt%).

[0050]

[0051] (5) Fix the base membrane so that the selective layer of the base membrane faces upwards on one side; pour in the aloe-emodin solution prepared in step (4) above, and mix and react at room temperature at a speed of 70 rpm for 6 hours under the condition of pH 8.5. After the reaction is completed, rinse thoroughly with deionized water and store the modified membrane in deionized water to obtain the aloe-emodin-enhanced bio-based antibacterial and anti-fouling separation membrane (labeled as PVDF-DA).

[0052] Example 2: Preparation of a bio-based antibacterial and antifouling separation membrane enhanced with aloin

[0053] The difference between this embodiment and Example 1 is that in step (2), the amount of DETA added is 0.01 wt%, and an aloin-enhanced bio-based antibacterial and antifouling separation membrane (PVDF-DA(1:1)) is prepared. Example 1: Surface morphology characterization of the aloin-enhanced bio-based antibacterial and antifouling separation membrane.

[0054] The surface and cross-sectional morphology of the PVDF, PVDF-D, and PVDF-DF films in Example 1 were observed using a field emission scanning electron microscope (SEM, JSM-6330F, NEC Corporation). The films were dried in a vacuum drying oven beforehand. Before observation, conductive adhesive was applied to the copper stage of the sample, and small square-cut film pieces were fixed onto the conductive adhesive. The sample surface was then sputter-coated with gold and observed under an accelerating voltage of 5 kV.

[0055] Figure 1 These are surface and cross-sectional morphology observation images of the PVDF, PVDF-D, and PVDF-DF films from Example 1. Figure 1 It is evident that the PVDF base film possesses a fibrous network microporous structure. The surface of the PVDF-D membrane is almost indistinguishable from that of the base PVDF membrane, indicating minimal impact on the membrane's morphology. The PVDF-DF membrane surface contains numerous nanoscale protrusions and microcracks. Cross-sectional analysis reveals that, compared to the base PVDF membrane, the PVDF-DF membrane prepared by grafting aloe-emodin has a deposited layer approximately 190 nm thick, exhibiting a porous structure.

[0056] Test Example 2: Flux and Organic Pollution Resistance Test of Aloe-Enhanced Bio-based Antibacterial and Antifouling Separation Membrane

[0057] The pure water flux and water contact angle of the separation membrane were tested using the following methods:

[0058] Pure water flux measurement: The measurement was performed using a cross-flow filtration device (CF016D, Sterlitech, USA), with an effective membrane area of ​​8 cm². 2 The filtration temperature was controlled at 25℃, the test pressure at 1 bar, and the membrane surface flow rate at 0.079 m / s. The membrane was pre-pressed with pure water, and after the flux stabilized, the permeate flux J was recorded. The calculation formula is:

[0059]

[0060] Where V represents the permeate volume (L), and A represents the effective membrane area (m²). 2 ), where Δt represents the filtering time (h).

[0061] The water contact angles of the PVDF, PVDF-D, and PVDF-DF membranes in Example 1 were tested. The water contact angle (CA) in air medium was measured using a droplet shape analyzer (DSA25E, Kruss GmbH, Germany). Specifically, a 2μL droplet was dropped onto the membrane surface and held for 5 seconds. The droplet profile was recorded using the droplet shape analyzer, and the angle between the gas, liquid, and solid phases at this point was calculated as the water contact angle of the sample. Each membrane was tested at least five times, and the average value was taken.

[0062] Figure 2 Schematic diagrams of the surface properties of the PVDF, PVDF-D, and PVDF-D-F membranes in Example 1. Among them, Figure 2 (a) is the surface water contact angle of the membrane; Figure 2 (b) is the surface charge property of the membrane.

[0063] From Figure 2 (a), it can be seen that the water contact angles of PVDF, PVDF-D, and PVDF-D-A are 85.62°, 56.38°, and 36.12° respectively, all having good hydrophilicity. The water contact angle of the PVDF-D membrane is slightly lower than that of the base membrane PVDF, mainly because polar groups such as -OH and -NH2 are generated on the surface of the base membrane PVDF in the DETA aqueous solution. The water contact angle of the PVDF-D-A membrane is significantly reduced, indicating that the introduction of aloin will cause a further improvement in the hydrophilicity of the base membrane surface. The main reason is that the aloin molecule has polyhydroxy groups such as resorcinol, and the hydroxy groups can easily form hydrogen bonds with water, increasing the affinity between the membrane surface and water.

[0064] From Figure 2 (b), it can be seen that the order of the isoelectric points of the separation membranes is PVDF < PVDF-D < PVDF-D-A. The negative charge on the surface of the PVDF-D membrane decreases significantly. This is because after amination modification, the membrane surface has different amounts of -NH and -NH2 groups, and the amino groups undergo protonation, making the membrane surface positively charged. The negative charge on the surface of the PVDF-D-A membrane decreases significantly, probably because the O in the phenolic hydroxyl group approaches the benzene ring skeleton due to p-π conjugated electron clouds, making it easy to dissociate H + , and the degree of deprotonation is greater.

[0065] Figure 3 Separation performance diagrams of the PVDF, PVDF-D, PVDF-D-F membranes in Example 1 and the PVDF-D-A(1:1) membrane in Example 2. Among them, Figure 3 (a) is the water flux of the membrane; Figure 3 (b) is the anti-organic fouling performance of the membrane.

[0066] From Figure 3 (a), it can be seen that the fluxes of the PVDF, PVDF-D, PVDF-D-A, and PVDF-D-A(1:1) membranes are: 248 L·m -2 ·h -1 ·bar -1 (LMH bar -1 ), 522 L·m -2 ·h -1 ·bar -1 (LMH bar-1 ), 217 L·m -2 ·h -1 ·bar -1 (LMH bar -1 ), 308 L·m -2 ·h -1 ·bar -1 (LMH bar -1 When hydrophilic modification (PVDF-DA, PVDF-DA(1:1)) is used, the membrane flux decreases slightly because aloin imparts a hydration layer to the membrane substrate surface, which increases the membrane resistance, but still maintains excellent membrane flux.

[0067] Depend on Figure 3 (b) It can be seen that PVDF, upon contact with E. coli filtrate (CFU = 4 × 10⁻⁶), 7 After this, the membrane flux dropped sharply, indicating that a large number of pollutants were adsorbed on the membrane surface. Bacteria gradually aggregated to form large-sized fouling, causing membrane pore blockage and a significant decrease in flux. At the same time, the bacteria have a certain degree of adhesiveness and can adhere tightly to the membrane surface, making them difficult to clean.

[0068] Figure 3 In (b), the flux of the PVDF-D membrane still showed a sharp decline. The main reason for this was that the membrane pore size increased after treatment with the polyamine under alkaline conditions, making it easier for fouling to clog the membrane pores. However, due to the presence of the positively charged hydration protective layer, it was able to partially resist the tight complexation of pollutants with the membrane surface. Therefore, after rinsing with pure water, most of the fouling on the membrane surface was easily cleaned.

[0069] Compared to polyvinylidene fluoride (PVDF) membranes, PVDF-DA membranes exhibit a lower flux decline in the initial stage. This is because, after modification with aloin, the carboxyl groups on the membrane surface are covered by the hydroxyl groups on the aloin, and the hydration layer acts as a fouling defense layer, making it difficult for most pollutants to adhere firmly to the membrane surface. Furthermore, aloin affects the membrane structure for microorganisms, reducing microbial adhesion to the membrane surface. Therefore, after rinsing with pure water, a small amount of pollutants remain on the PVDF-DA membrane surface, and the flux can recover relatively well.

[0070] Test Example 3: Biofouling Resistance Test of Aloe-Enhanced Bio-based Antibacterial and Antifouling Separation Membrane

[0071] The antibacterial properties of PVDF, PVDF-D, and PVDF-DF from Example 1 were tested. The test methods are as follows:

[0072] Escherichia coli (ATCC 8739, purchased from Guangdong Provincial Microbial Culture Collection Center) was used as the model bacterium in the experiment. Before the experiment, the experimental bacterial strains needed to be cultured separately. 10 μL of the stock solution was inoculated into 250 mL of LB liquid medium and cultured at 30°C for 12 h. The bacterial solution was then centrifuged at 5000 r / min for 10 min, washed three times with PBS buffer, and finally diluted to OD200. 600 A concentration of 0.4 was prepared for use. The PVDF, PVDF-D, and PVDF-DF from Example 1 were cut to 1×1cm pieces respectively. 2 After determining the area of ​​the membrane, place it in a 24-well plate containing 600 μL of LB liquid culture medium and a diluted bacterial suspension, respectively, so that the membrane is in contact with the bacterial suspension. After incubation at 30°C for 12 h, gently wipe off the unadsorbed bacteria on the membrane surface with PBS buffer solution. Place the rinsed membrane in a centrifuge tube containing 10 mL of PBS buffer solution and sonicate for 10 min. Dilute the sonicated bacterial samples with PBS buffer to prepare a series of bacterial solutions with different concentration gradients, and then perform CFU plate counting on the obtained bacterial suspensions.

[0073]

[0074] Where R represents the antibacterial rate (%) of the modified membrane; N0 represents the total number of colonies (CFU) formed on the surface of the original separation membrane; N represents the total number of colonies (CFU) formed on the surface of the modified separation membrane; and d represents the dilution factor.

[0075] Figure 4 A comparison of the antibacterial properties of PVDF, PVDF-D, and PVDF-DF films. Figure 4 It can be seen that the PVDF-DF separation membrane prepared in this invention has relatively good antibacterial properties. The number of colonies on the PVDF and PVDF-D membranes are approximately 6.03 ± 0.11 × 10⁻⁶. 9 4.83±0.61×10 9 The number of colonies on the PVDF-DF separation membrane was approximately 1.12 ± 0.13 × 10⁻⁶. 8 Compared to PVDF, the amount of bacterial colonies adhering to the membrane was reduced by 90.42%.

[0076] Figure 5SEM images show the morphological changes of bacteria after co-culturing PVDF, PVDF-D, and PVDF-DF membranes with bacterial suspension. The scanning electron microscope results show that the E. coli adsorbed on the PVDF-D membrane are slender rod-shaped with smooth and intact cell membranes. In contrast, the E. coli on the PVDF-DF membrane exhibit two main morphologies: one is that the cell bodies are shrunken and smaller, but still retain some cellular integrity; the other is that the overall cell structure is altered, with the damaged cell surface enveloped by irregular aggregates.

[0077] The above results indicate that the bio-based antibacterial and antifouling separation membrane enhanced with aloin possesses both "pollution resistance" and "active antibacterial" capabilities. The hydration protective layer effectively blocks the tight complexation of organic pollutants with the membrane surface, and aloin molecules "actively attack" microorganisms near the membrane surface, disrupting their normal growth.

[0078] The foregoing examples are merely illustrative, used to explain some features of the method described in this invention. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are demonstrated by the applicant's actual experimental results. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A method for preparing a bio-based bacteriostatic anti-pollution separation membrane based on aloin reinforcement, characterized in that, The preparation method comprises the following steps: S1. mixing a base film and a polyamine solution under alkaline conditions, and cleaning; S2. adding an aloe glycoside solution to obtain the aloe glycoside reinforced bio-based bacteriostatic and anti-pollution separation film; The mass ratio of the polyamine to the aloe glycoside is 1-10:0.02; The concentration of the aloe glycoside in the aloe glycoside solution is 1-2 wt%; The concentration of the polyamine in the polyamine solution is 0.02 wt%-0.08 wt%; The polyamine is selected from diethylene triamine; The base film is selected from one or more of polyether sulfone, polyvinylidene fluoride, polyacrylonitrile, polyethylene, polyvinyl chloride or polytetrafluoroethylene; The structure of the aloe glycoside is shown in the following formula (I): （I） 。 2. The method of claim 1, wherein, The mass ratio of the polyamine to the aloe glycoside is 2-4:0.

02.

3. The preparation method according to claim 1, characterized in that, The concentration of the aloe glycoside in the aloe glycoside solution is 1 wt%.

4. The preparation method according to claim 1, characterized in that, The concentration of the polyamine in the polyamine solution is 0.02 wt%.

5. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. In step S2, the pH of the reaction is 8-10.

6. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The aloe glycoside solution further comprises a buffer solution.

7. The aloe glycoside reinforced bio-based bacteriostatic and anti-pollution separation film obtained by the preparation method in any one of claims 1-6.

8. The application of the aloe glycoside reinforced bio-based bacteriostatic and anti-pollution separation film in claim 7 in water treatment.

Images