Water purification material against biofilm attachment and preparation method thereof

Abstract

This invention relates to the field of water treatment materials technology, specifically disclosing a water purification material with anti-biofilm adhesion and its preparation method. The material uses activated carbon aerogel with a three-dimensional interconnected network structure and high conductivity as its matrix framework. A composite functional layer consisting of polydopamine-coated MXene nanosheets and phosphotungstic acid nanoclusters is constructed on its surface and pore walls through a stepwise loading process. This material, through its polydopamine-MXene core-shell structure design, effectively stabilizes MXene and firmly immobilizes phosphotungstic acid, comprehensively leveraging the surface effects of two-dimensional materials, the redox interference of polyacids, and the electrochemically assisted regeneration of the conductive framework—a triple synergistic anti-biofilm effect. This material exhibits excellent bacterial adhesion inhibition and biofilm formation inhibition capabilities, while also possessing high flux, high adsorption efficiency, and good environmental compatibility, making it suitable for scenarios prone to biological pollution, such as circulating cooling water, advanced wastewater treatment, and drinking water purification.

Description

Technical Field

[0001] This invention relates to the field of water treatment materials technology, specifically to a water purification material and its preparation method that resists biofilm adhesion. Background Technology

[0002] In many fields such as industrial circulating cooling water, municipal sewage treatment, reverse osmosis membrane systems, aquaculture and medical water pipelines, biofouling on material surfaces is the core problem that leads to decreased system efficiency, increased energy consumption, high operating costs and even equipment failure. Microorganisms colonize, proliferate and secrete extracellular polymers on material surfaces, forming complex biofilms that not only severely clog filter pores or pipes and greatly increase fluid resistance, but also cause localized corrosion, accelerate the accumulation of pollutants, and become a breeding ground for pathogens.

[0003] Currently, strategies for dealing with biofilms mainly include: adding chemical bactericides, but these carry risks of producing toxic byproducts, causing microbial resistance, and secondary environmental pollution; using antibacterial materials, but the continuous leaching of metal ions leads to ecotoxicity; photocatalytic materials heavily rely on ultraviolet light and have limited effect on deep biofilms; and physical cleaning or hydrophilic modification of membrane surfaces, but these have problems such as short-lasting effects, high energy consumption, or decreased mechanical properties. In particular, traditional porous adsorption materials, with their huge specific surface area, while efficiently adsorbing pollutants, are also prone to becoming a breeding ground for microbial aggregation and biofilm formation, leading to rapid decay of adsorption performance and a sharp drop in flux, i.e., the so-called biofouling phenomenon.

[0004] Therefore, developing a new type of water purification material that integrates high efficiency in resisting biofilm adhesion, long-lasting antibacterial properties, high pollutant adsorption capacity, good water permeability, and environmental friendliness has become a technological bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] The primary objective of this invention is to address the common problems of insufficient long-term effectiveness, high environmental risk, single functional mechanism, or susceptibility to external conditions in existing antibiofilm materials by providing a water purification material with multiple synergistic antibiofilm mechanisms, stable performance, and environmental friendliness.

[0006] The second objective of this invention is to provide a method for preparing the above-mentioned water purification material, wherein the method is process-controllable and can ensure that the functional components are uniformly and firmly loaded on the activated carbon aerogel framework and form the desired composite structure.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a water purification material that resists biofilm adhesion. The material is characterized by using a three-dimensional porous conductive activated carbon aerogel as a structural framework and conductive network. On this framework, two key functional components are loaded: one is MXene nanosheets (denoted as PDA-MXene) with a polydopamine layer on the surface, and the other is phosphotungstic acid nanoclusters. Phosphotungstic acid can be loaded on both the activated carbon aerogel framework and the polydopamine layer of PDA-MXene, together forming a complete composite antibacterial functional layer.

[0008] The PDA-MXene is preferably in the form of a few layers or a single layer. With nanosheets as the core, a dense polydopamine coating layer with a thickness of approximately 2 to 10 nanometers is formed on its surface through in-situ oxidative polymerization of dopamine. This polydopamine layer not only greatly improves the antioxidant stability of MXene in aqueous environments, but its abundant phenolic hydroxyl and amino functional groups also provide numerous binding sites for the immobilization of phosphotungstic acid, preferably with a classic Keggin structure. .

[0009] In terms of material composition, the total loading of PDA-MXene and phosphotungstic acid on activated carbon aerogel is controlled between 5% and 30%. The ratio of the two affects the final performance of the material. The molar ratio of PDA-MXene to phosphotungstic acid (based on Ti and W elements) is preferably in the range of 1:0.5 to 1:2. Within this range, the physical antibacterial effect and biochemical interference effect of the material can achieve a good balance and synergy.

[0010] The activated carbon aerogel used as the supporting substrate should have a porosity greater than 90% to ensure low flow resistance and high loading space, and a specific surface area greater than 800 m². 2 / g, to ensure sufficient pollutant adsorption capacity, and conductivity greater than 0.1S / cm, which is the basis for its ability to achieve electric-assisted regeneration function.

[0011] Secondly, this invention provides a method for preparing the above-mentioned anti-biofilm adhesion water purification material, which mainly includes three core steps: The first step is to prepare a PDA-MXene dispersion by dispersing MXene nanosheets in a weakly alkaline Tris-HCl buffer solution, adding dopamine hydrochloride, and stirring the mixture at room temperature and in the dark for 12 to 24 hours. After the reaction is complete, unreacted monomers and byproducts are removed by centrifugation and washing to obtain a uniform and stable PDA-MXene dispersion.

[0012] The second step is phosphotungstic acid preloading. The clean activated carbon aerogel block is immersed in a phosphotungstic acid aqueous solution of a certain concentration and soaked at a temperature of 4 to 25°C for 6 to 24 hours to allow phosphotungstic acid molecules to be fully adsorbed into the pores and surface of the aerogel. After that, it is taken out and dried to obtain an intermediate preloaded with phosphotungstic acid.

[0013] The third step is vacuum-assisted composite, in which the above intermediate is immersed in the PDA-MXene dispersion prepared in the first step and placed in a vacuum environment for treatment. The pressure difference drives the dispersion to fully penetrate into all the pores of the intermediate. Then, heat treatment is carried out at 60 to 80°C for 1 to 2 hours to promote further cross-linking and curing of the polydopamine layer. Finally, after drying, the final water purification material is obtained.

[0014] The advantage of this stepwise preparation method is that it first pre-fixes easily soluble phosphotungstic acid onto the huge inner surface of the aerogel through physical adsorption, and then uses the strong adhesion of polydopamine and vacuum assistance to uniformly introduce and cover PDA-MXene onto the phosphotungstic acid-loaded framework. This sequence is conducive to the formation of a tighter electrostatic or coordination interaction between PDA-MXene and phosphotungstic acid, thereby forming a stable composite functional layer and effectively preventing the loss of phosphotungstic acid during use.

[0015] Thirdly, the present invention also covers specific applications of the aforementioned material and devices containing the material. The material can be directly used to construct or fill filters in circulating water systems, biofilm control modules in wastewater treatment, and deep purification devices for drinking water, etc. In particular, when applied, the conductivity of the activated carbon aerogel framework can be fully utilized by applying a weak DC or pulse voltage of 0.1 to 1.0V to both ends of the material. This low-voltage electric field can induce the generation of trace amounts of electrochemically active substances (such as hydrogen peroxide) or generate electroosmotic flow, thereby achieving online electrochemical-assisted removal of initial biofilm on the surface without affecting the structure of the main material, significantly extending the effective service life of the material.

[0016] The beneficial effects of this invention are: 1. In this invention, the material combines the physical cutting effect of the sharp edges of PDA-MXene nanosheets, which can directly destroy the bacteria in contact; the biochemical interference effect of immobilized phosphotungstic acid as an electron acceptor, which can continuously disrupt the metabolism and quorum sensing of microorganisms, inhibiting their proliferation and film formation; and the electric-assisted regeneration capability provided by the activated carbon aerogel conductive network, which can be cleaned online by applying a weak electric field. Multiple mechanisms work together to achieve comprehensive and long-lasting anti-biofilm efficacy.

[0017] 2. In this invention, MXene is coated with polydopamine, which fundamentally improves the disadvantage of MXene's easy oxidation and ensures its long-term stability. At the same time, the polydopamine layer acts as a "molecular glue" to firmly anchor MXene and phosphotungstic acid to the activated carbon skeleton, which greatly reduces the dissolution loss of phosphotungstic acid in water flow and avoids the environmental toxicity risk caused by the continuous release of metal ions in traditional silver-loaded materials.

[0018] 3. In this invention, the material inherits the high-efficiency adsorption characteristics of activated carbon aerogel, has a strong ability to remove organic pollutants in water, and its excellent anti-biofilm properties ensure that the material pores are not easily blocked by biofilm during long-term operation, thereby maintaining a high water flux. Combined with the electric-assisted regeneration function, the flux can be further restored, and the filter material replacement cycle can be greatly extended.

[0019] 4. In this invention, the raw materials involved in the preparation process are all commercially available common chemicals. The surface polymerization, solution impregnation, vacuum assistance, heat treatment and other techniques used are all conventional technologies in the field of material preparation. The process conditions are mild, the parameter window is wide, the repeatability is good, and it has the potential for large-scale production. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but 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.

[0021] Unless otherwise specified, all experimental methods used are conventional methods, and all materials and reagents used are commercially available.

[0022] Example 1: Preparation of PDA-MXene / PW12@CAG composite material This embodiment demonstrates the process of preparing composite materials according to the preferred process and proportions of the present invention.

[0023] S1. Raw material preparation: MXene raw material: selectively etched using hydrofluoric acid solution. Ceramic powder. The specific steps are as follows: Take 1g of... The powder was slowly added to 20 mL of a 40 wt% hydrofluoric acid solution, and the mixture was continuously stirred magnetically at 35 °C for 24 hours. After the reaction, the powder was repeatedly washed with deionized water by centrifugation until the pH of the supernatant was >6. The resulting precipitate was redispersed in 100 mL of deionized water and ultrasonically exfoliated in an ice-water bath under argon protection (300 W power) for 1 hour. Then, it was centrifuged at 3500 rpm for 1 hour, and the upper brownish-black dispersion was collected to obtain a few-layer chromatography solution with a concentration of ~1.5 mg / mL. Aqueous dispersion.

[0024] Activated carbon aerogel: using resorcinol and formaldehyde as carbon precursors, through catalytic sol-gel process, aging, acetone solvent exchange, and supercritical fluid extraction. The material was dried and then carbonized and activated at 800℃ in a nitrogen / carbon dioxide mixed atmosphere to obtain CAG blocks with dimensions of approximately 1×1×0.5cm. 3 Characterization showed that its porosity was 92%, its BET specific surface area was 1100 m² / g, and its volumetric conductivity was approximately 0.5 S / cm.

[0025] Other chemicals: phosphotungstic acid, dopamine hydrochloride, and tris(hydroxymethyl)aminomethane were all of analytical grade, and the water used in the experiment was deionized water.

[0026] S2. Preparation of PDA-MXene dispersion: Measure 20 mL of the above MXene dispersion and place it in a 250 mL beaker. Under magnetic stirring, add 80 mL of pre-prepared Tris-HCl buffer (pH=8.5, concentration 10 mM). After mixing evenly, add 80 mg of dopamine hydrochloride to the system. Then wrap the beaker with aluminum foil to protect it from light and continue to react with magnetic stirring at room temperature for 24 hours. After the reaction is complete, transfer the mixture to a centrifuge tube and centrifuge at 8000 rpm for 10 minutes. Discard the supernatant and redisperse the precipitate with deionized water and centrifuge and wash. Repeat this process three times to thoroughly remove unreacted monomers and small molecule byproducts. Finally, redisperse the washed precipitate in 50 mL of deionized water to obtain a homogeneous and stable PDA-MXene dispersion for later use.

[0027] S3. Phosphotungstic acid preloading: Accurately weigh a piece of dried CAG (approximately 0.1 g), prepare 5 mL of 0.02 mol / L phosphotungstic acid aqueous solution, completely immerse the CAG in the solution, and place the container in a 4°C refrigerator for 12 hours to allow the phosphotungstic acid to fully diffuse and adsorb into the pores of the CAG. After the time is up, carefully remove the CAG with tweezers, gently wipe away any remaining droplets on the surface with filter paper, and then transfer the sample to the sample tray of a freeze dryer. Freeze-dry for 24 hours to obtain an intermediate preloaded with phosphotungstic acid, denoted as PW12@CAG.

[0028] S4. Vacuum-assisted composite: The PW12@CAG intermediate prepared above was completely immersed in the PDA-MXene dispersion prepared in step S2. The entire system was placed in a vacuum dryer, the vacuum pump was started, and the pressure inside the chamber was reduced to about -0.095 MPa and maintained for 30 minutes. During this process, a large number of bubbles were observed to escape from the inside of the CAG, indicating that the dispersion penetrated into the pores under the pressure difference. After that, the vent valve was slowly opened to restore the pressure to normal. This "vacuuming-restoring normal pressure" process was repeated 3 times to ensure that the dispersion was fully wetted. After impregnation, the composite material was removed and the excess dispersion on the surface was gently absorbed with filter paper. The sample was then heat-treated in a 60°C oven for 2 hours to further crosslink and cure the polydopamine layer, thereby enhancing the bonding strength. Finally, the sample was freeze-dried again to obtain the final composite material, denoted as PDA-MXene / PW12@CAG. According to inductively coupled plasma optical emission spectrometry (ICP-OES), the total loading of PDA-MXene and PW12 in the material is approximately 15 wt%, and the molar ratio of Ti to W is close to 1:1.

[0029] The design basis and advantages of the above-mentioned stepwise preparation process are as follows: First, easily soluble phosphotungstic acid (PW12) is pre-loaded onto the CAG framework through physical adsorption. Then, under vacuum assistance, the negatively charged PW12 reacts with protonated amino groups (-NH3) prepared in a weakly alkaline buffer solution. + A strong electrostatic attraction is generated between PDA and MXene, driving the PDA-MXene nanosheets to tightly anchor onto the PW12@CAG framework and form a coating. The polydopamine (PDA) layer acts as a "multifunctional molecular bridge" in this process; it not only stabilizes MXene through covalent / non-covalent interactions, but its abundant functional groups also interact with PW12 and CAG in multiple ways. The final heat treatment step promotes intermolecular crosslinking of the PDA layer, further enhancing the stability of the entire composite functional layer and effectively preventing the dissolution of PW12 during use.

[0030] Example 2: Preparation of composite materials with high phosphotungstic acid ratio This embodiment is used to investigate the effect of increasing the relative content of phosphotungstic acid on the material properties.

[0031] The preparation process is exactly the same as in Example 1, except that the concentration of the phosphotungstic acid aqueous solution in step S3 is changed to 0.1 mol / L. The parameters of the other steps remain unchanged. In the final composite material, the molar ratio of Ti to W is approximately 1:2.

[0032] Example 3: Preparation of high MXene ratio composite materials This embodiment is used to investigate the effect of increasing the relative content of MXene on material properties.

[0033] The preparation process is exactly the same as in Example 1, except that the concentration of the phosphotungstic acid aqueous solution in step S3 is reduced to 0.02 mol / L. The parameters of the other steps remain unchanged. In the final composite material, the molar ratio of Ti to W is approximately 2:1.

[0034] Example 4: Preparation of a polydopamine-free control sample (MXene / PW12@CAG) This embodiment aims to verify the importance of the polydopamine modification layer.

[0035] Without performing step S2 (i.e. without preparing the PDA-MXene dispersion), the original MXene dispersion obtained in step S1 is used directly for step S4. That is, the PW12@CAG intermediate is immersed in the original MXene dispersion and subjected to the same vacuum-assisted compounding, heat treatment and drying process. The resulting material is denoted as MXene / PW12@CAG.

[0036] Example 5: Preparation of a phosphotungstic acid-free control sample (PDA-MXene@CAG) This embodiment aims to verify the necessity of the phosphotungstic acid component.

[0037] Without performing step S3 (i.e., without phosphotungstic acid preloading), the original pure CAG is directly used in step S4, that is, the pure CAG is immersed in PDA-MXene dispersion and subjected to the same vacuum-assisted compounding, heat treatment and drying process. The resulting material is denoted as PDA-MXene@CAG.

[0038] Example 6: Preparation of MXene-free control sample (PW12@CAG) This embodiment aims to verify the necessity of the MXene component.

[0039] Steps S2 and S4 are omitted; only step S3 is performed, which involves immersing pure CAG in a 0.05 mol / L phosphotungstic acid solution. After impregnation and drying, the material is obtained and denoted as PW12@CAG. Example 7: Preparation of a non-conductive substrate control sample (PDA-MXene / PW12@AC) This embodiment aims to verify the key role of the activated carbon aerogel conductive framework.

[0040] Commercially purchased block activated carbon (AC) was cut into pieces the same size as CAG, with a BET specific surface area of ​​approximately 1000 m². 2 / g (but without macroscopic conductivity) completely replaced the activated carbon aerogel in Example 1. Subsequently, strictly following steps S3 and S4 of Example 1, PW12 and PDA-MXene were loaded onto the AC block to obtain a control sample, denoted as PDA-MXene / PW12@AC. Comparative Example 1: Pure Activated Carbon Aerogel (CAG) Pure activated carbon aerogel, obtained using the same raw materials and preparation method as in Example 1, without any functionalization loading, was used as the benchmark for performance evaluation.

[0041] Comparative Example 2: Commercial polymer microfiltration membranes Commercially available polyvinylidene fluoride flat sheet microfiltration membranes with a nominal pore size of 0.22 μm were selected. This is a microfiltration material widely used in water treatment, but it is susceptible to biological contamination.

[0042] Comparative Example 3: Commercial silver-impregnated activated carbon (Ag@AC) Commercially available silver-loaded granular activated carbon was purchased, with a silver loading of approximately 2 wt%. An appropriate amount of this material was taken and pressed into a sheet-like shape with dimensions similar to the sample in Example 1 under certain pressure in a mold for performance comparison testing.

[0043] Comparative Example 4: One-step mixed load comparison sample This comparative example aims to verify the superiority of the stepwise preparation process of the present invention.

[0044] The process sequence of Example 1 was changed: PDA-MXene dispersion was first prepared according to step S2, and then the dispersion was directly mixed with 0.05 mol / L phosphotungstic acid aqueous solution at a certain volume ratio to obtain a mixed dispersion of PDA-MXene and PW12. Pure CAG was immersed in this mixture and vacuum-assisted compounding, heat treatment and drying were carried out in the same way as step S4 of Example 1. This method attempts to achieve simultaneous loading of all functional components in one step.

[0045] Comparative Example 5: Conventional photocatalytic material (PDA-MXene / TiO2@CAG) This comparative example uses common photocatalytic antibacterial materials as a reference.

[0046] In step S3 of Example 1, a commercially available P25 type titanium dioxide nanoparticle aqueous dispersion (ultrasonicated) of equal mass concentration was used to replace the phosphotungstic acid solution. PDA-MXene was then loaded according to step S4 of Example 1, and the resulting material was denoted as PDA-MXene / TiO2@CAG.

[0047] Comparative Example 6: Commercial Biofouling-resistant Filter Cartridge A commercially available composite filter cartridge (mainly composed of zinc-loaded activated carbon and antibacterial polymer) that claims to have anti-biofilm function was selected. Its core material was extracted and processed into a size and shape similar to that of the sample in Example 1 for performance comparison testing.

[0048] Effect verification example To comprehensively evaluate the performance of the material of the present invention (represented by Example 1) and to systematically compare it with each example and comparative example, the following experiments were designed for testing and characterization.

[0049] Antibacterial adhesion performance test (short-term): Cut each material sample into 1×1cm pieces. 2 After sterilization with ethanol and rinsing with sterile PBS, the samples were placed in 24-well plates. 2 mL of E. coli (ATCC 25922) suspension prepared with PBS was added to each well, resulting in a bacterial concentration of [missing information]. The well plate was placed in a constant temperature incubator at 37℃ and statically incubated for 4 hours. After incubation, the sample was removed and gently rinsed 3 times with sterile PBS to remove unadhered airborne bacteria. The sample was then transferred to a centrifuge tube containing 5 mL PBS and sonicated for 10 minutes to remove bacteria attached to the surface. An appropriate amount of elution buffer was serially diluted and spread on LB agar plates. After incubation at 37℃ upside down for 24 hours, colony counting was performed. The bacterial adhesion inhibition rate was obtained by calculating the number of colony-forming units per unit sample surface area and comparing it with the adhesion amount of Comparative Example 1 (pure CAG). Anti-biofilm formation performance test (long-term): Using Pseudomonas aeruginosa (PAO1) as the model biofilm-forming bacterium, the samples were placed in 24-well plates, and 2 mL of M9 minimum medium containing 1 / 10 concentration of LB medium was added to each well. Pseudomonas aeruginosa was then inoculated to the final concentration. The culture medium was kept statically at 30℃ for 72 hours without changing the culture medium to simulate the biofilm formation process. After the culture was completed, the bacterial culture in the wells was carefully aspirated, and the samples were gently rinsed three times with PBS to remove airborne bacteria. Then, 1 mL of 0.1% crystal violet solution was added, and the samples were stained at room temperature for 15 minutes. The staining solution was discarded, and the samples were washed thoroughly with deionized water until the washings were colorless. Subsequently, 2 mL of 95% ethanol was added to dissolve the crystal violet bound to the biofilm, and the samples were gently shaken for 10 minutes to ensure complete dissolution. 200 μL of the solution was transferred to a 96-well plate, and the absorbance at 590 nm was measured using a microplate reader. The value is positively correlated with biofilm biomass. The biofilm inhibition rate is calculated by comparing it with the OD value of Comparative Example 1. Dynamic filtration and contaminant removal performance test: Each material was processed into a circular disc with a diameter of 2cm and a thickness of approximately 0.5cm, and placed in a custom-made stainless steel filter tank, with an effective filtration area of ​​3.14cm². 2Prepare simulated contaminated water: using deionized water as a base, add humic acid (as a model organic pollutant) to a concentration of 10 mg / L, and inoculate with E. coli until... Dead-end filtration experiments were conducted under a constant transmembrane pressure of 0.5 bar, and the initial pure water flux was recorded. Then, the system was switched to simulated polluted water and operated continuously for 24 hours. The flux was recorded at the end of the operation. And calculate flux retention rate ( (×100%), and at the beginning of the experiment and 24 hours after the start of the experiment, influent and effluent water samples were taken respectively, and their chemical oxygen demand was determined by rapid digestion spectrophotometry to calculate the COD removal rate; Electrically Assisted Regeneration Effect Test: After completing the above 24-hour pollution experiment, a regeneration test was conducted on the sample from Example 1. A 0.5V DC regulated power supply was applied to the electrodes on both sides of the filter tank, with the material acting as the cathode. The test was run for 30 minutes, during which pure water was circulated at a low flow rate. After the power supply was removed, the stable flux of the material in pure water was tested again. And calculate the flux recovery rate ( (×100%) Material stability and dissolution test: The sample of Example 1 and the sample of Comparative Example 3 (silver-loaded activated carbon) were placed in conical flasks, and sufficient deionized water was added. They were continuously shaken and soaked in a shaker at 25°C and 150 rpm for 30 days. Samples were taken at regular intervals, filtered through a 0.22 μm filter membrane, and the concentrations of tungsten (W) and silver (Ag) in the filtrate were determined by inductively coupled plasma mass spectrometry to evaluate the dissolution of functional components. The table below summarizes the main performance test results for all embodiments and comparative examples: Table 1. Basic performance test results of the examples and comparative examples

[0050] (Note: The antibacterial test for Comparative Example 5 was conducted under visible light irradiation.) Table 2. Basic performance test results of the examples and comparative examples

[0051] As shown in Table 1, the material of this invention exhibits excellent antibacterial and anti-biofilm adhesion efficacy. The bacterial adhesion inhibition rate and biofilm inhibition rate of Example 1 (optimized sample) are both close to 99%, proving the effectiveness of the synergistic effect of PDA-MXene, PW12 and CAG framework. Specifically, the performance of Example 4 (without PDA modification) and Example 5 (without PW12) decreased significantly, respectively confirming the key role of the polydopamine layer in stabilizing MXene and strengthening interfacial bonding, and the core position of phosphotungstic acid in providing long-term biochemical interference and inhibiting biofilm formation. Example 6 (without MXene) had the lowest performance, indicating that the lack of the unique two-dimensional surface structure and nanoscale roughness provided by MXene nanosheets significantly weakened the material's physical barrier and interference ability against initial bacterial adhesion. Compared with the comparative examples, although Comparative Example 3 (silver-loaded activated carbon) had a high bacterial adhesion inhibition rate, its biofilm inhibition rate (80.2%) was significantly lower than that of Example 1, indicating its insufficiency in inhibiting long-term biofilm formation. Comparative Example 5 ( The performance of the control sample is generally poor and heavily dependent on light conditions. The test results of the control sample 6 (commercial anti-fouling filter) show that although it has a certain anti-adhesion ability (bacterial adhesion inhibition rate of 85.2%), its long-term biofilm inhibition rate (72.5%) is relatively limited, indicating that its antibacterial efficacy may not be able to cope with the serious biofilm formation problem in a long time.

[0052] As shown in Table 2, the material of this invention exhibits significant advantages in long-term operational performance, regeneration capacity, and environmental safety. Example 1 shows a 24-hour flux retention rate as high as 88.5%, and after electro-assisted regeneration, the flux recovery rate reaches 96.2%. This fully demonstrates the material's excellent anti-fouling ability and unique advantage of online regeneration. This advantage stems from the conductive network of the CAG; when a weak cathode voltage is applied, an oxygen reduction reaction may occur at the material / solution interface to generate trace amounts of hydrogen peroxide (…). The presence of reactive oxygen species such as α, β, and γ, along with the electroosmotic flow generated, facilitates the physical stripping of attached biomass. In comparison, Example 7 (non-conductive AC matrix) exhibited extremely low flux retention and recovery rates, directly confirming that the CAG conductive network is the physical basis for achieving high-flux stable operation and electrochemically assisted regeneration. Regarding environmental safety, the W element leaching in Example 1 was below the detection limit (<5 ppb), indicating that the functional components were firmly immobilized. In contrast, Comparative Example 3 (silver-loaded activated carbon) showed an Ag ion leaching rate as high as 850 ppb, posing a clear ecotoxicity risk. This highlights the effectiveness of the material in this invention through immobilization and a non-leaching mechanism (the oxidation-reduction reaction of PW12). The original interference) achieves antibacterial and environmentally friendly properties. In addition, the performance of Comparative Example 4 (one-step process) is inferior to that of Example 1, indicating that the stepwise preparation process of "phosphotungstic acid pre-loading-vacuum assisted composite PDA-MXene" adopted by the present invention is crucial for building a stable and efficient composite functional layer. The flux retention rate (45.5%) and pollutant removal rate (88.5%) of Comparative Example 6 (commercial filter) are at a medium level, and it does not have an electric assisted regeneration function. Its performance is lower than that of the optimized example of the present invention (Example 1), which further highlights the comprehensive advantages of the material of the present invention in terms of integrated performance and long-term regeneration capability.

[0053] In summary, based on the data in Tables 1 and 2, the PDA-MXene / PW12@CAG composite material provided by this invention successfully achieves synergistic effects of multiple anti-biofilm mechanisms. It not only has near-complete inhibition of bacterial attachment and biofilm formation (Table 1), but also maintains high purification efficiency and high throughput during long-term dynamic operation. It can be efficiently regenerated through low-energy-consumption electrical assistance and avoids the leaching of harmful substances (Table 2). The specific material combination (PDA-MXene, PW12, CAG), optimized component ratio, and key stepwise preparation process are essential conditions for obtaining the above-mentioned comprehensive performance. This material provides an innovative solution for solving the problem of biological pollution in water treatment that is efficient, long-lasting, green, and has intelligent regeneration potential.

[0054] In the description of this specification, the terms "preparation example," "example," "various examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that example or preparation example, which are included in at least one example or preparation example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same example or preparation example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more examples or preparation examples.

[0055] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A water purification material resistant to biofilm adhesion, characterized in that, include: Three-dimensional porous conductive activated carbon aerogel framework; Polydopamine-modified MXene nanosheets loaded on the activated carbon aerogel framework; Phosphotungstic acid nanoclusters loaded on the activated carbon aerogel framework and / or the polydopamine-modified MXene nanosheets.

2. The water purification material according to claim 1, characterized in that, In the polydopamine-modified MXene nanosheets, MXene is either few-layered or monolayered. Nanosheets, in which Representing -OH, -O, or -F surface end groups, the polydopamine modified layer is a coating layer with a thickness of 2-10 nm formed by in-situ polymerization of dopamine.

3. The water purification material according to claim 1, characterized in that, The phosphotungstic acid nanoclusters have a Keggin structure. Based on the mass of the activated carbon aerogel framework, the total loading of the polydopamine-modified MXene nanosheets and the phosphotungstic acid nanoclusters is 5 wt% to 30 wt%.

4. The water purification material according to claim 3, characterized in that, The molar ratio of the polydopamine-modified MXene nanosheets to the phosphotungstic acid nanoclusters, calculated in terms of Ti and W elements, is 1:0.5 to 1:

2.

5. The water purification material according to claim 1, characterized in that, The activated carbon aerogel has a porosity greater than 90% and a specific surface area greater than 800 m². 2 / g, conductivity greater than 0.1S / cm.

6. A method for preparing a water purification material with anti-biofilm adhesion as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Preparation of polydopamine-modified MXene dispersion: MXene nanosheets were dispersed in Tris-HCl buffer at pH=8.5, dopamine hydrochloride was added, and the mixture was stirred and reacted at room temperature in the dark for 12-24 hours. After centrifugation and washing, the mixture was redispersed to obtain polydopamine-modified MXene dispersion. S2. Phosphotungstic acid preloading: Activated carbon aerogel is impregnated in an aqueous solution of 0.01-0.1 mol / L phosphotungstic acid for 6-24 hours at 4-25℃, then removed and dried to obtain the phosphotungstic acid preloading intermediate; S3. Vacuum-assisted compounding: The intermediate obtained in step S2 is immersed in the dispersion obtained in step S1, and the mixture is treated under vacuum to allow the dispersion to fully penetrate. Then, it is heat-treated at 60-80°C for 1-2 hours, and finally dried to obtain the water purification material.

7. The preparation method according to claim 6, characterized in that, In step S1, the amount of dopamine hydrochloride added is such that its concentration in the reaction system is 0.5-2.0 mg / mL.

8. The application of the anti-biofilm water purification material according to any one of claims 1-5 in a circulating water system, a sewage treatment system or a drinking water purification system.

9. A water treatment device, characterized in that, Water purification materials containing any one of claims 1-5 that resist biofilm adhesion.

10. The water treatment apparatus according to claim 9, characterized in that, The device is equipped with a power supply for applying a DC or pulse voltage of 0.1-1.0V to the water purification material.

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