Preparation method of high-flux Janus distillation membrane based on interfacial fusion of supramolecular interaction

Abstract

In view to the problems of large mass transfer resistance and low water production rate caused by poor interface compatibility of traditional Janus distillation membrane, a Janus distillation membrane interface fusion based on supramolecular interaction and a high-flux Janus distillation membrane preparation method are disclosed, which has the advantages of stable mass transfer, limited evaporation and anti-pollution and moisture resistance, and significantly improves the water production efficiency and desalination robustness of the distillation membrane. The bridging modification layer is constructed by strong hydrogen bond, the interface homogeneity is enhanced, the hydrogel layer is stably anchored with the bridging layer through the supramolecular interaction of hydrogen bond, pi-pi stacking and coordination bond between polyphenol-metal-polymer, the interface compatibility is significantly improved, the water is quickly transported to the evaporation interface, the evaporation phase change energy barrier is reduced, the steam flux is improved, the pollutants are effectively blocked and the pollutant adhesion energy barrier is improved, the membrane wetting and pollution are delayed, and the method is suitable for high-salinity wastewater treatment containing oil and surfactant, and has good industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of membrane distillation technology, and in particular to a method for preparing a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion. Background Technology

[0002] With the rapid development of industries such as chemical, pharmaceutical, textile, petroleum, and food processing, the discharge of high-salinity wastewater is increasing year by year. Its high salt content and complex composition pose a serious threat to water and soil environments. Direct discharge of high-salinity wastewater can lead to soil salinization, eutrophication of water bodies, and groundwater pollution, disrupting the ecological balance. Currently, the main technologies for treating high-salinity wastewater include evaporation crystallization and reverse osmosis, but these methods generally suffer from high energy consumption, complex operation, and difficulty in treating concentrated wastewater, limiting their large-scale application. Membrane distillation (MD), as an emerging membrane separation technology, uses vapor pressure difference as the mass transfer driving force and can achieve efficient desalination at lower temperatures, making it particularly suitable for the treatment of high-salinity wastewater and showing promising application prospects.

[0003] However, traditional hydrophobic membranes are susceptible to the effects of surfactants, oil contaminants, and fouling ions during molecular dynamics (MD) processes, leading to problems such as membrane wetting, fouling, and scaling, resulting in decreased membrane performance or even failure. To improve the wettability and antifouling properties of membranes, researchers have proposed the Janus membrane structure, which incorporates a hydrophilic layer on the surface of a hydrophobic membrane. This type of membrane delays fouling and wetting by blocking contaminants from contacting the hydrophobic base membrane through the hydrophilic layer, but this often results in increased membrane mass transfer resistance, frequently at the expense of evaporation flux.

[0004] Hydrogels, as functional materials composed of three-dimensional cross-linked polymer networks, possess tunable microstructures and physicochemical properties, and can reduce enthalpy of evaporation by adjusting segment-water molecule interactions. Combining hydrogels with a hydrophobic substrate to form Janus membranes can synergistically enhance interfacial hydration and evaporation efficiency while maintaining high flux, and significantly improve the membrane's antifouling and antiwetting capabilities.

[0005] Conventional loading methods (such as physical deposition) often result in weak adhesion between the hydrogel layer and the hydrophobic membrane, leading to insufficient interfacial bonding. This makes the membrane prone to detachment or peeling under operational stresses (such as hydraulic fluctuations, temperature changes, or mechanical vibrations), severely impacting the membrane's long-term stability. Secondly, due to the significant chemical differences between the hydrogel and the hydrophobic membrane (opposite hydrophilicity and hydrophobicity), micron- or nanoscale gaps easily form at the interface. These gaps not only reduce structural integrity but also induce localized water accumulation during mass transfer. Specifically, when water vapor is transported from the hydrophilic side to the hydrophobic side, water accumulation at the gaps increases interfacial mass transfer resistance, forming a so-called "interfacial barrier," resulting in a longer water vapor transport path and reduced efficiency. Furthermore, localized water accumulation can promote contaminant deposition, further exacerbating membrane fouling and scaling problems. Experimental studies have shown that this interfacial problem significantly reduces the flux of composite membranes; for example, in membrane distillation applications, the flux attenuation rate can reach over 30%. It also induces non-uniform wetting, ultimately leading to irreversible damage to the membrane structure and shortening its lifespan. Current interface strengthening strategies primarily focus on physical bonding methods such as mechanical interlocking, using electrospinning to construct anchoring structures to improve Janus interface adhesion strength. However, these strategies often face the dilemma of mutually exclusive interfacial stability and mass transfer efficiency, and require expensive facilities, making them unsuitable for hydrogel systems. Furthermore, existing hydrogel-based Janus membranes are generally studied in isolation to study the bulk properties of the hydrogel, neglecting the bonding mechanism between the surface and the substrate. This results in poor structural stability and severe flux attenuation in the hydrogel-based membranes. These issues collectively restrict the commercial application of hydrogel-hydrophobic membrane composite structures, highlighting the shortcomings of existing methods in interface engineering.

[0006] Therefore, the core problem urgently needing to be solved in this field is how to achieve a strong, uniform, and stable bond between hydrogels and hydrophobic membranes to eliminate interfacial gaps and hydrophilic / hydrophobic barriers, thereby reducing mass transfer resistance and improving water vapor transport flux and overall efficiency. The goal is to develop a Janus membrane distillation membrane with strong interfacial bonding, low mass transfer resistance, high flux, excellent antifouling performance, simple preparation process, and environmental friendliness. This will promote the practical application of membrane distillation technology in high-salinity wastewater treatment, enhancing interfacial adhesion and avoiding localized water accumulation and detachment without compromising the hydrophilicity of the hydrogel or the structure of the hydrophobic membrane. Summary of the Invention

[0007] The purpose of this invention is to provide a novel method for preparing high-throughput Janus distillation membranes based on supramolecular interactions to achieve interfacial fusion, thereby solving the problems of increased mass transfer resistance and low water production performance caused by insufficient interfacial stability in traditional Janus distillation membranes. This method employs a "bridging-anchoring" strategy. First, a polymeric viscous bridging modification layer is constructed on the surface of a hydrophobic base membrane using strong hydrogen bonding between amino and fluorine groups to improve the homogeneity of the hydrophilic-hydrophobic interface. Then, a polyphenol-metal-polymer hydrogel layer is constructed in situ using a simple solvent evaporation method. This allows for strong hydrogen bonding and π-π stacking interactions between the phenolic hydroxyl groups of the hydrogel layer and the catechol groups of the bridging modification layer, as well as coordination interactions between the metal and hydroxyl groups. This achieves multiple supramolecular anchoring between the hydrogel layer and the bridging modification layer, thereby improving interfacial compatibility, promoting rapid water transport to the evaporation interface, and ensuring that the water reaching the interface via the hydrogel is in a low enthalpy of vaporization, reducing the evaporation phase transition energy barrier and increasing steam flux. The constructed polyphenol-metal-polymer hydrogel layer is formed by cross-linking polyvinyl alcohol, an environmentally friendly hydrogel material. The introduction of a polyphenol-metal network enhances the structural openness of the hydrogel, reducing the mass transfer resistance of the hydrophilic layer, and strengthens the supramolecular interaction between the hydrogel layer and the bridging modified layer, thus enhancing interfacial bonding. Based on this design, this invention can achieve reduced resistance to water molecule transport and in-situ formation of the hydrophilic layer with simple operation, while ensuring enhanced interfacial stability between the base layer and the hydrophilic layer. This results in a synergistic breakthrough in interfacial stability, mass transfer efficiency, and long-term operational reliability of membrane distillation membranes, making it particularly suitable for the stable treatment of high-salinity wastewater.

[0008] To achieve the above objectives, the present invention provides the following solution: This invention provides a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion, comprising, from bottom to top, a hydrophobic base membrane, a bridging modification layer, and a polyphenol-metal-polymer hydrogel layer; the bridging modification layer is a polydopamine / polyethyleneimine composite layer; the polyphenol-metal-polymer hydrogel layer is formed by cross-linking polyphenol materials, metal chlorides, and polymers through supramolecular interactions.

[0009] Preferably, the hydrophobic base membrane is one of polytetrafluoroethylene membrane and polyvinylidene fluoride membrane, with a pore size of 0.1-0.45 μm.

[0010] Preferably, the mass concentration of polydopamine in the bridging modified layer is 0.05-5.0 mg / mL, and the molecular weight of polyethyleneimine is 300-10000 Da, with a mass concentration of 0.05-5.0 mg / mL.

[0011] Preferably, the polyphenolic material includes one of protocatechuic acid, tannic acid, gallic acid, quercetin, and pyrogallol, with a mass concentration of 1-15 wt%; the metal chloride includes one of FeCl3, CuCl2, AlCl3, and ZnCl2, with a concentration of 0.03-1.0 mol / L; and the polyvinyl alcohol has a degree of alcoholysis of 78.5-99.0 mol% and a mass concentration of 5-20 wt%.

[0012] Preferably, the molar ratio of the polyphenol material to the metal chloride is 1:(2-9).

[0013] Preferably, the polymer includes one of polyvinyl alcohol, chitosan, gelatin, and polyethylene glycol hydrogel materials.

[0014] This invention also provides a method for preparing a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion, comprising the following steps: S1. Dissolve polydopamine and polyethyleneimine in a Tris-HCl buffer solution with pH=8.5 and a concentration range of 0.05-5.00 mM, and stir to obtain a bridging modified layer solution; S2. Deposit the bridging modified layer solution onto the surface of the hydrophobic base film, let it stand for 10-12 h, and then dry to obtain the bridging modified hydrophobic film; S3. Dissolve the polyphenol material in an ethanol solution to obtain a first solution, dissolve the metal chloride in water to obtain a second solution, and dissolve the polyvinyl alcohol in water and heat and stir to obtain a third solution; S4. Mix the first solution, the second solution, and the third solution in a mass ratio of 1:1:(5-20), heat and stir, and then let stand to remove bubbles to obtain the hydrogel precursor solution; S5. The hydrogel precursor solution is coated onto the surface of the bridging layer modified hydrophobic membrane and dried to obtain the Janus membrane distillation membrane.

[0015] Preferably, in step S2, the drying temperature is 40-60 ℃ and the drying time is 6-8 h.

[0016] Preferably, in step S3, the polyvinyl alcohol solution is stirred at 90-95 °C for 6-10 h.

[0017] Preferably, in step S5, the coating method is scraping, spraying, spin coating, or natural flow coating, and the coating thickness is 50-300 μm.

[0018] This invention also provides an application of a high-throughput Janus distillation membrane based on supramolecular interaction to achieve interfacial fusion in membrane distillation treatment of high-salt wastewater. The polyphenol-metal-polymer hydrogel layer of the high-throughput Janus distillation membrane based on supramolecular interaction to achieve interfacial fusion is oriented towards the feed liquid, which is saline wastewater or high-salt wastewater containing surfactants / mineral oil.

[0019] The present invention achieves the following beneficial technical effects compared to the prior art: 1. The interfacial compatibility between the hydrophilic and hydrophobic layers of the Janus membrane is significantly enhanced. Existing Janus membranes typically form their hydrophilic layers through surface deposition, direct coating, or layer-by-layer assembly, resulting in weak interfacial adhesion between the surface layer and the substrate. This leads to interlayer delamination during long-term operation or in high-salt environments. This invention addresses this issue by constructing a polydopamine / polyethyleneimine bridging modified layer and utilizing the multiple supramolecular interactions (hydrogen bonds, π-π stacking, coordination bonds, etc.) of the polyphenol-metal-polymer hydrogel layer to achieve stable anchoring between the hydrophilic layer and the hydrophobic substrate. This strategy significantly improves interfacial compatibility and overall structural stability, ensuring the long-term operational reliability of the Janus membrane in high-salt wastewater treatment and resolving the problem of insufficient hydrophilic-hydrophobic interfacial adhesion in traditional Janus membranes.

[0020] 2. Reduced mass transfer resistance and increased flux Existing Janus distillation membranes suffer from high mass transfer resistance due to the introduction of an additional dense layer, resulting in low flux during membrane distillation, significantly lower than that of hydrophobic membranes. This invention constructs a bridging layer on a hydrophobic membrane using an interface fusion modulation strategy and anchors the hydrophilic hydrogel layer through supramolecular interactions, thereby improving membrane flux and optimizing mass transfer resistance. The resulting Janus distillation membrane not only maintains its water production capacity but also significantly enhances it, effectively solving the problem of low flux in traditional Janus membranes and ensuring the efficient and stable operation of the hydrogel Janus membrane distillation membrane in high-salt wastewater treatment. The hydrophilic hydrogel layer in this invention, rich in hydrophilic groups and with low osmotic resistance, provides a rapid transport channel for water molecules, which helps reduce mass transfer resistance. Furthermore, a robust fixation on the hydrophobic membrane is achieved through a "bridging-anchoring" strategy, significantly improving interfacial compatibility and enabling rapid water transport to the evaporation interface. Simultaneously, strong hydrogen bonds are formed between the hydrophilic polyphenol-metal-polymer hydrogel and water molecules, weakening hydrogen bonds between water molecules in the hydrophilic layer and increasing the proportion of intermediate water within the hydrogel layer, effectively reducing the enthalpy of vaporization. Through interfacial compatibility adjustment, the confined evaporation strategy ensures that water reaching the interface via the hydrogel is in a low enthalpy of vaporization state, lowering the evaporation phase transition energy barrier and thus significantly improving the membrane evaporation flux.

[0021] 3. Simultaneously achieves anti-fouling, anti-scaling, and wettability properties. Commercial hydrophobic membranes and conventional Janus membranes are prone to permanent failure due to wetting and fouling of membrane pores when surfactants and salt ions coexist. The Janus membrane of this invention utilizes a "bridging-anchoring" strategy between the hydrophilic surface and hydrophobic substrate, along with a polyphenol-metal network structure within the hydrogel layer, to regulate interlayer interfacial compatibility and the hydration of the hydrophilic layer. Combined with supramolecular interactions and the hydration layer effect, this results in a membrane surface exhibiting hydrophilic and oleophobic properties, and a robust interfacial bonding force. This reduces the risk of liquid accumulation in interfacial pores, thereby enhancing the critical Laplace pressure between the feed liquid and the substrate, and delaying surfactant diffusion. Simultaneously, it significantly increases the energy barrier for mineral oil / gypsum adhesion to the membrane surface, ensuring high permeability while possessing excellent anti-wetting, anti-fouling, and anti-scaling properties, effectively preventing the wetting, fouling, and scaling of the membrane by surfactants, scale ions, and oils in wastewater.

[0022] 4. Simple preparation process and controllable structure Compared to existing conventional Janus membrane preparation processes that are complex, environmentally unfriendly, and prone to instability, this invention employs a simple and easy-to-implement coating-drying method based on a solvent evaporation strategy. This process is simple, environmentally friendly, mild, and inexpensive. Furthermore, by utilizing polyphenol-metal-polymer hydrogels and combining them with polyphenol-metal coordination modulation, the structure and properties of the hydrophilic layer (such as hydrophilicity, pore size, and surface chemistry) can be precisely controlled, achieving stable and efficient membrane distillation operation. Therefore, this invention, using inexpensive and environmentally friendly raw materials and a simple and mild preparation method, achieves a high degree of structural tunability, demonstrating promising prospects for industrial production and application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A flowchart illustrating the preparation method of a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion, as provided by this invention. Figure 2 Peel strength test of high-throughput Janus distillation membrane based on supramolecular interaction to achieve interfacial fusion provided by the present invention; Figure 3 The high-throughput Janus distillation membrane based on supramolecular interaction to achieve interface fusion provided in Example 4 of the present invention and the Janus membrane cross-section scanning electron microscope image of Comparative Example 2 are shown. Figure 4Evaporation flux and salt rejection rate of the high-throughput Janus distillation membrane based on supramolecular interaction to achieve interfacial fusion provided by the present invention; Figure 5 Antifouling and wetting resistance tests were conducted on the high-throughput Janus distillation membrane based on supramolecular interaction to achieve interfacial fusion provided in Example 4 of the present invention and the Janus membrane of Comparative Example 1. Figure 6 Scanning electron microscope (SEM) images of the surface and cross-section of the high-throughput Janus distillation membrane based on supramolecular interaction to achieve interfacial fusion provided in Example 4 of the present invention and the Janus membrane of Comparative Example 1, for structural resistance testing. Detailed Implementation

[0025] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" of the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] 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.

[0028] The purpose of this invention is to provide a method for preparing a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion. This method involves sequentially constructing a bridging modification layer and a polyphenol-metal-polymer hydrogel layer on the surface of a hydrophobic base membrane. Multiple supramolecular interactions are utilized to achieve high-strength interfacial fusion between the hydrophilic and hydrophobic layers, significantly improving the structural stability and mass transfer performance of the Janus membrane. The implementation process and effects of this invention are described in detail below through specific embodiments.

[0029] The main raw materials and parameters of Examples 1-5 and Comparative Examples 1-2 of the present invention are shown in Table 1.

[0030] Table 1 Polydopamine / mg / mL Polyethyleneimine (molecular weight 600 Da) / mg / mL 15 mL polyvinyl alcohol (degree of hydrolysis 98.0-99.0 mol%) / wt% 2.5 mL protocatechuic acid / wt% 2.5 mL ferric chloride / mol / L Example 1 PTFE hydrophobic membrane (0.22 μm) 2.0 2.0 10 2 0.04 Example 2 PTFE hydrophobic membrane (0.22 μm) 2.0 2.0 10 4 0.09 Example 3 PTFE hydrophobic membrane (0.22 μm) 2.0 2.0 10 6 0.13 Example 4 PTFE hydrophobic membrane (0.22 μm) 2.0 2.0 10 8 0.17 Example 5 PTFE hydrophobic membrane (0.22 μm) 2.0 2.0 10 10 0.22 Comparative Example 1 PTFE hydrophobic membrane (0.22μm) - - - - - Comparative Example 2 PTFE hydrophobic membrane (0.22 μm) 2.0 2.0 10 - - Example 1 like Figure 1 As shown, firstly, a polytetrafluoroethylene hydrophobic membrane with a pore size of 0.22 μm was selected as the hydrophobic base membrane.

[0031] Next, prepare the bridging modification layer solution: Dissolve 2.0 mg / mL polydopamine and 2.0 mg / mL polyethyleneimine with a molecular weight of 600 Da in a Tris-HCl buffer solution with a pH of 8.5 and a concentration of 0.05 mmol / L. Stir at room temperature for 5 minutes to ensure that the solution is fully dissolved and mixed evenly.

[0032] Next, the bridging modified layer solution was uniformly deposited on the surface of the hydrophobic base film, and allowed to stand for 12 hours for interface modification. Then, the excess solution was poured off, and the film was dried at 45 °C for 6 hours to obtain the bridging modified hydrophobic film.

[0033] Subsequently, a hydrogel precursor solution was prepared. 2 wt% protocatechuic acid was dissolved in 50% ethanol solution and stirred for 20 minutes to obtain the first solution. 0.04 mol / L ferric chloride was dissolved in deionized water and stirred for 20 minutes to obtain the second solution. 10 wt% polyvinyl alcohol with a degree of hydrolysis of 98.0-99.0 mol% was stirred at 95°C for 6 hours until completely dissolved to obtain the third solution. The first, second, and third solutions were mixed at a mass ratio of 1:1:6 and stirred at 80°C for 10 minutes. The mixture was then placed in a 30°C incubator for 6 hours to remove bubbles, yielding a homogeneous hydrogel precursor solution.

[0034] Finally, the hydrogel precursor solution was coated onto the surface of the bridging layer modified hydrophobic membrane using a blade coating method with a blade gap of 100 μm. After coating, the membrane was dried at room temperature to form a polyphenol-metal-polymer hydrogel layer, thus obtaining a Janus distillation membrane based on supramolecular interactions.

[0035] Example 2 The difference between this embodiment and Example 1 is that the mass concentration of protocatechuic acid in the hydrogel precursor solution is 4 wt%, and the concentration of ferric chloride is 0.09 mol / L. The remaining steps and parameters are the same as in Example 1.

[0036] Example 3 The difference between this embodiment and Example 1 is that the mass concentration of protocatechuic acid in the hydrogel precursor solution is 6 wt%, and the concentration of ferric chloride is 0.13 mol / L. The remaining steps and parameters are the same as in Example 1.

[0037] Example 4 The difference between this embodiment and Example 1 is that the mass concentration of protocatechuic acid in the hydrogel precursor solution is 8 wt%, and the concentration of ferric chloride is 0.17 mol / L. The remaining steps and parameters are the same as in Example 1.

[0038] Example 5 The difference between this embodiment and Example 1 is that the mass concentration of protocatechuic acid in the hydrogel precursor solution is 10 wt%, and the concentration of ferric chloride is 0.22 mol / L. The remaining steps and parameters are the same as in Example 1.

[0039] Comparative Example 1 Untreated polytetrafluoroethylene hydrophobic membranes were used directly as control samples.

[0040] Comparative Example 2 The bridging layer modified hydrophobic membrane was prepared using the same steps as in Example 1, but without coating with the hydrogel precursor solution, i.e. it only had a bridging modification layer and no hydrogel layer.

[0041] A series of performance tests were conducted on the membrane samples prepared in the above embodiments and comparative examples, including interfacial peel strength, contact angle, evaporation flux, salt rejection rate, antifouling and anti-fouling performance, etc. The test results are as follows: (a) Peel strength test Using a SUSTCMT4304 electronic universal testing machine with a 90° peel clamp, the film sample was cut into strips of 1cm x 10cm and adhered to a metal strip with 3M adhesive. The other side was then stretched at a tensile speed of 1 mm / min under the clamp. The peel strength test results are as follows: Figure 2 As shown in the figure, the Janus membrane prepared by this invention achieves enhanced interfacial peel strength, solving the problem of poor adhesion between the hydrophilic layer and the substrate in traditional Janus membranes, and improving operational stability. Furthermore, the cross-sectional scanning electron microscope images of the membranes in Comparative Example 2 and Example 4, as shown in Figure 3, also clearly demonstrate that the supramolecular enhancement strategy achieves complete fusion and tight adhesion of the Janus interface, eliminating interfacial voids and reducing the possibility of mechanical peeling of the composite membrane.

[0042] (ii) Hydrophilic and oleophobic test Using a KinoSL250 contact angle meter, the water contact angles of the membrane surface and bottom in air and the oil contact angles in pure water were tested using pure water and mineral oil, respectively. The test results are shown in Table 2. The contact angle of the hydrogel-based Janus membrane distillation membrane prepared in this invention is 46-57° on the membrane surface and about 120° at the bottom. This indicates that the hydrogel construction significantly enhances the hydrophilicity of the membrane surface, while the underlying structure still maintains effective water vapor transport channels, achieving the characteristics of the Janus structure. Simultaneously, the underwater oil contact angle of the Janus membrane is >145°, exhibiting excellent hydrophilic and oleophobic properties compared to the hydrophobic membrane in Comparative Example 1. This significantly improves the membrane's antifouling properties and enables long-term stability in the treatment of oily and high-salt wastewater.

[0043] Example 1 46.72±2.33 115.84±5.26 145.54±1.32 Example 2 55.97±1.83 117.31±3.27 147.10±2.84 Example 3 56.49±2.40 116.65±4.12 146.73±4.32 Example 4 50.95±4.30 118.48±0.77 146.52±2.58 Example 5 56.63±1.72 119.78±0.31 145.85±1.96 Comparative Example 1 125.08±7.40 119.21±0.45 32.61±1.00 Comparative Example 2 52.64±2.26 116.78±1.25 137.22±4.31 (III) Evaporation flux and salt rejection test A direct contact membrane distillation apparatus was used, with an initial volume of 1000 mL of 35 g / L sodium chloride solution and pure water as the feed and distillate, respectively. The inlet temperatures of the feed and distillate were maintained at 60 ± 2 ℃ and 20 ± 2 ℃, respectively. A peristaltic pump was used to control the flow rate on both sides at 400 mL / min. The mass and conductivity of the distillate were continuously recorded for 12 h, and the steam flux and salt rejection rate were calculated. The results are as follows: Figure 4 As shown in the figure, Comparative Example 2, a traditional hydrophilic dense membrane, exhibits a significantly reduced steam flux compared to the hydrophobic membrane in Comparative Example 1, decreasing from 25.08 kg m³. -2 h -1 Reduced to 19.84 kg m -2 h -1 The Janus membrane prepared by this invention exhibits improved permeation flux compared to Comparative Example 1, with Example 4 achieving a membrane flux of 28.81 kg m³. -2 h -1 Compared with Comparative Example 1 and Comparative Example 2, the membranes showed improvements of 14.87% and 45.21%, respectively, while maintaining a salt rejection rate of nearly 100%. This indicates that the construction of hydrogel layers enhanced by supramolecular interactions can not only improve interlayer bonding, but also improve the vapor transport capacity of the membrane by regulating the hydration effect and microstructure. This allows for increased membrane vapor flux and stable desalination even after the introduction of an additional dense layer.

[0044] (iv) Wetting resistance and anti-fouling performance test The wettability and antifouling properties of the membrane were tested using a 35 g / L sodium chloride solution containing 0.04 mmol / L sodium dodecyl sulfate and 1 g / L mineral oil as the feed liquid. The results are as follows: Figure 5As shown, in Comparative Example 1, the flux gradually decreased to 0 within 200 min of system operation, while the conductivity increased to over 2200 μs / cm, indicating that the membrane was easily wetted and prone to pore blockage due to oil contamination, leading to membrane failure. The Janus membrane prepared in this invention maintained a stable flux of 25 kg m³ within 720 min of operation. -2 h -1 With a conductivity of around 15 μs / cm, the Janus membrane exhibits excellent antifouling and wettability.

[0045] Anti-scaling test The fouling of the membrane was characterized after continuous filtration for 24 h using a 35 g / L sodium chloride solution containing 20 mmol / L sodium sulfate and 20 mmol / L calcium chloride as the feed liquid. The results are as follows: Figure 6 As shown, Comparative Example 1 has a surface covered with dense, plate-like and rod-shaped monoclinic CaSO4 crystals, and the crystals penetrate the substrate as observed in the cross-section, indicating that scaling-induced physical blockage and interfacial wetting effects ultimately lead to the overall failure of the membrane. The Janus membrane prepared in this invention, as shown in Example 4, did not exhibit obvious CaSO4 crystals on its surface or cross-section; only a small number of amorphous nanoparticle clusters were present, indicating that it successfully inhibited gypsum nucleation and crystal growth, significantly improving the membrane's anti-scaling properties.

[0046] In summary, this invention successfully prepared Janus distillation membranes with high interfacial stability, high throughput, and excellent antifouling / anti-scaling / anti-wetting properties through an interface fusion strategy achieved by supramolecular interactions. The preparation process is simple, green, and low-cost, and is suitable for the long-term stable treatment of high-salinity wastewater, showing broad prospects for industrial applications.

[0047] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion, characterized in that, It includes a hydrophobic base membrane, a bridging modification layer, and a polyphenol-metal-polymer hydrogel layer arranged sequentially from bottom to top; the bridging modification layer is a polydopamine / polyethyleneimine composite layer; the polyphenol-metal-polymer hydrogel layer is formed by cross-linking polyphenol materials, metal chlorides, and polymers through supramolecular interactions.

2. The high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion according to claim 1, characterized in that, The hydrophobic base membrane is one of polytetrafluoroethylene membrane and polyvinylidene fluoride membrane, with a pore size of 0.1-0.45 μm.

3. The high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion according to claim 1, characterized in that, The bridging modified layer contains polydopamine with a mass concentration of 0.05-5.0 mg / mL and polyethyleneimine with a molecular weight of 300-10000 Da and a mass concentration of 0.05-5.0 mg / mL.

4. The high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion according to claim 1, characterized in that, The polyphenolic material includes one of protocatechuic acid, tannic acid, gallic acid, quercetin, and pyrogallol, with a mass concentration of 1-15 wt%; the metal chloride includes one of FeCl3, CuCl2, AlCl3, and ZnCl2, with a concentration of 0.03-1.0 mol / L; the degree of alcoholysis of the polyvinyl alcohol is 78.5-99.0 mol%, with a mass concentration of 5-20 wt%.

5. The high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion according to claim 4, characterized in that, The molar ratio of the polyphenol material to the metal chloride is 1:(2-9).

6. The high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion according to claim 1, characterized in that, The polymer includes one of the following hydrogel materials: polyvinyl alcohol, chitosan, gelatin, and polyethylene glycol.

7. A method for preparing a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Dissolve polydopamine and polyethyleneimine in a Tris-HCl buffer solution with pH=8.5 and a concentration range of 0.05-0.50 mM, and stir to obtain a bridging modified layer solution; S2. Deposit the bridging modified layer solution onto the surface of the hydrophobic base film, let it stand for 10-12 h, and then dry to obtain the bridging modified hydrophobic film; S3. Dissolve the polyphenol material in an ethanol solution to obtain a first solution, dissolve the metal chloride in water to obtain a second solution, and dissolve the polyvinyl alcohol in water and heat and stir to obtain a third solution; S4. Mix the first solution, the second solution, and the third solution in a mass ratio of 1:1:(5-20), heat and stir, and then let stand to remove bubbles to obtain the hydrogel precursor solution; S5. The hydrogel precursor solution is coated onto the surface of the bridging layer modified hydrophobic membrane and dried to obtain the Janus membrane distillation membrane.

8. The method for preparing a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion according to claim 7, characterized in that, In step S2, the drying temperature is 40-60 ℃ and the drying time is 6-8 h.

9. The method for preparing a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion according to claim 7, characterized in that, In step S5, the coating method is scraping, spraying, spin coating or natural flow coating, and the coating thickness is 50-300 μm.

10. An application of a high-throughput Janus distillation membrane based on supramolecular interactions to achieve interfacial fusion as described in any one of claims 1-6 in membrane distillation treatment of high-salinity wastewater, characterized in that, The polyphenol-metal-polymer hydrogel layer of the high-throughput Janus distillation membrane based on supramolecular interaction to achieve interface fusion is directed toward the feed liquid, which is saline wastewater or high-salt wastewater containing surfactants / mineral oil.

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