A porous antibacterial adsorbent and its preparation method
By using Pickering foam technology to directionally enrich zinc oxide particles at the pore wall interface, the problem of random distribution of antibacterial components is solved, the antibacterial efficiency and material stability are improved, and efficient ammonia nitrogen wastewater treatment is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LUDONG UNIVERSITY
- Filing Date
- 2026-04-14
- Publication Date
- 2026-06-02
Smart Images
Figure CN122124759A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functional materials technology, and in particular to a porous antibacterial adsorbent and its preparation method. Background Technology
[0002] Ammonia nitrogen wastewater is widely found in industries such as aquaculture, landfill leachate, chemical processing, and pharmaceuticals. Its discharge easily leads to eutrophication of water bodies, posing a threat to the ecological environment and human health. Adsorption methods, due to their simple process, stable operation, and wide applicability, have become one of the effective means of treating low- to medium-concentration ammonia nitrogen wastewater. Natural clay minerals such as attapulgite, due to their high specific surface area and cation exchange capacity, are often used as ammonia nitrogen adsorbents.
[0003] However, in actual wastewater treatment, the presence of microorganisms and their attachment to material surfaces, along with biofilm formation, can clog material pores and increase mass transfer resistance, thus significantly reducing adsorption efficiency and lifespan. Therefore, introducing antibacterial components (such as zinc oxide, ZnO) to construct antibacterial adsorption materials has become a research hotspot. Zinc oxide is a broad-spectrum, highly efficient inorganic antibacterial agent.
[0004] Existing technologies typically introduce ZnO into adsorbent materials through methods such as impregnation, co-precipitation, or direct mixing. While these methods are simple, they have significant drawbacks: ZnO particles are randomly distributed within the material, making them prone to aggregation or embedding within the material. This results in a large amount of ZnO failing to effectively contact microorganisms in the water, leading to low antibacterial efficiency. On the other hand, microorganisms preferentially adhere to the pore wall surface of porous materials. Therefore, directionally enriching antibacterial components in the pore wall interface region is crucial for improving antibacterial efficiency, but existing technologies lack precise means to control this spatial distribution.
[0005] For example, Chinese invention patent CN104759265A discloses a method for preparing porous foam heavy metal adsorbent materials. Its focus is on constructing macroscopic porous blocks using a template method, but it does not address the spatial distribution regulation of antibacterial components within the pore structure. Similarly, Chinese invention patent CN107442081A discloses a method for constructing porous heavy metal adsorbents using Pickering water-based foam as a template. This method utilizes solid particles to stabilize the foam and create pores, but its purpose is limited to constructing porous structures and does not involve the directional enrichment and distribution regulation of functional components (such as antibacterial agents) at the pore wall interfaces.
[0006] Therefore, developing a method to effectively regulate the directional distribution of antibacterial components at the pore wall interface to improve the utilization efficiency of antibacterial agents and the material's resistance to biofouling is a key problem that needs to be solved by existing technologies. Summary of the Invention
[0007] The purpose of this invention is to provide a porous antibacterial adsorbent and its preparation method, to solve the problems in existing technologies where antibacterial components are randomly distributed within the material and cannot be effectively enriched at the pore wall interface, resulting in low antibacterial efficiency and susceptibility to biological contamination. The method of this invention enables the directional enrichment of zinc oxide at the pore wall interface region, thereby improving the effective utilization rate of antibacterial components and giving the material both high-efficiency ammonia nitrogen adsorption and antibacterial properties.
[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A porous antibacterial adsorbent and its preparation method, comprising the following steps: S1. Disperse surfactants, polymeric additives, attapulgite, and zinc oxide in water to form a uniform suspension; S2. Mechanically stir the suspension obtained in step S1 to introduce gas and form Pickering foam stabilized by attapulgite and zinc oxide particles. S3. Add polymerizable monomers, crosslinking agents and initiators to the Pickering foam obtained in step S2, mix them evenly, and carry out a polymerization reaction under heating conditions to solidify the foam structure and form a porous material with a three-dimensional interconnected pore structure. S4. The porous material obtained in step S3 is washed and dried to obtain the porous antibacterial adsorbent.
[0009] Preferably, in step S1, the surfactant is one or more of hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, Tween surfactants, or saponins; and the polymeric auxiliaries are one or more of chitosan, sodium alginate, polyvinyl alcohol, or polyacrylamide.
[0010] Preferably, the components in step S1 are as follows by mass percentage: surfactant 0.2% to 1.0%, polymeric additive 1.0% to 3.0%, attapulgite 1.0% to 10.0%, zinc oxide 5.0% to 15.0%, and the balance is water.
[0011] Preferably, in step S2, the mechanical stirring speed is 3000-6000 rpm and the stirring time is 10-20 minutes; the gas volume fraction of the resulting Pickering foam is 50%-90%.
[0012] Preferably, in step S3, the polymerizable monomer is one or more of 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, or acrylamide; the crosslinking agent is N,N′-methylenebisacrylamide; and the initiator is a redox initiation system composed of ammonium persulfate and sodium bisulfite.
[0013] Preferably, in step S3, the amount of polymerizable monomer added is 10% to 30% of the total mass of the system, the amount of crosslinking agent added is 20% to 30% of the monomer mass, and the amount of initiator added is 0.2% to 5% of the total mass of the system.
[0014] Preferably, in step S3, the polymerization reaction temperature is 50–70°C and the reaction time is 6–12 hours.
[0015] The present invention also provides a porous antibacterial adsorbent, which is prepared by any of the above preparation methods. The porous antibacterial adsorbent has a three-dimensional interconnected pore structure formed by a Pickering foam template, and the zinc oxide antibacterial component is enriched and distributed in the pore wall surface area.
[0016] In summary, the present invention has the following beneficial effects: Firstly, this invention creatively utilizes the interface self-assembly effect during the Pickering foam formation process to directionally enrich zinc oxide particles at the gas-liquid interface. In the subsequent polymerization and curing process, this interface structure is transformed in situ into the pore wall structure of the material, thereby realizing the controllable transformation of zinc oxide from the traditional random distribution inside the material to the directional distribution at the pore wall interface.
[0017] Secondly, because zinc oxide is enriched at the pore wall interface where microorganisms preferentially attach, the probability of contact between zinc oxide and microorganisms in the water and the effective contact area are significantly increased, thereby greatly improving the antibacterial efficiency, helping to slow down the formation of biofilm in the pores, ensuring the smooth flow of mass transfer channels, and improving the long-term stability of the material in the treatment of ammonia nitrogen wastewater containing microorganisms.
[0018] Thirdly, the zinc oxide particles in this invention are stably fixed in the pore wall structure, which reduces the problem of reduced activity caused by agglomeration, and at the same time enhances its bonding force with the matrix material, reducing the risk of loss under water flow.
[0019] Fourth, this invention integrates the three processes of porous structure construction, zinc oxide loading, and spatial distribution control through a one-step foaming-polymerization process, resulting in a simple and convenient process. By adjusting the amounts of attapulgite and zinc oxide, as well as the foaming conditions, the pore structure parameters of the material and the distribution density of zinc oxide on the pore walls can be effectively controlled, exhibiting excellent controllability. Attached Figure Description
[0020] Figure 1 The images show polarized light micrographs of the foam structure and corresponding bubble size distributions under different attapulgite addition amounts. In the figures, a–c are polarized light micrographs of the foam structure under different attapulgite addition amounts, and d–f are statistical results of the bubble size distribution under the corresponding conditions.
[0021] Figure 2Scanning electron microscope (SEM) images of porous materials prepared under different zinc oxide addition conditions are shown. In the images, a–c represent the pore structure morphology of the materials at low magnification, and d–f represent the surface morphology of the pore walls in the corresponding regions at high magnification.
[0022] Figure 3 The adsorption rate curve of ammonia nitrogen in water by the porous antibacterial adsorbent prepared in Example 1 of the present invention. Detailed Implementation
[0023] The present invention will be further described in detail below with reference to the accompanying drawings.
[0024] Example 1 At room temperature, 0.05 g of saponin (nonionic surfactant), 0.20 g of chitosan, 0.15 g of attapulgite, and 1.0 g of ZnO were added to 10 mL of deionized water. The mixture was stirred at 4500 rpm for 10 minutes to form a stable Pickering foam template. Subsequently, 1.5 g of the monomer 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 0.3 g of the crosslinking agent N,N′-methylenebisacrylamide (MBA) were added to the foam system, and stirring continued for 3 minutes. Finally, 0.05 g of the initiator ammonium persulfate (APS) and 0.05 g of sodium bisulfite (SBS) were added, and stirring continued for 0.5 minutes. The system was then placed in a 60°C oven for polymerization for 12 hours. The resulting product was washed with ethanol using a Soxhlet extraction for 24 hours and then dried to obtain the porous antibacterial adsorbent material described in this invention.
[0025] Comparative Example 1 This comparative example illustrates the effect of the order of zinc oxide addition on the material structure and properties. Under the same raw material composition and dosage conditions as Example 1 (0.05 g saponin, 0.20 g chitosan, 0.15 g attapulgite, 1.0 g ZnO, 10 mL deionized water), the order of zinc oxide addition was changed. Specifically, the process was as follows: First, saponin and attapulgite were added to deionized water and stirred at 4500 r / min for 10 min to form a stable Pickering foam template. Then, after the foam structure was formed, ZnO was added to the system and stirred at a low stirring speed (1000 r / min) for 1–2 min to achieve simple dispersion. Next, the same amounts of AMPS, MBA, APS, and SBS as in Example 1 were added, and polymerization, washing, and drying were carried out under the same conditions to obtain the control sample.
[0026] Since zinc oxide is added after the gas-liquid interface is formed, it does not participate in the construction process of the interface structure. Therefore, it is mainly randomly dispersed inside the material matrix and does not accumulate at the pore wall interface.
[0027] Example 2 At room temperature, 0.05 g saponin, 0.20 g chitosan, 0.15 g attapulgite, and 1.5 g ZnO were added to 10 mL of deionized water. The mixture was stirred at 4500 rpm for 10 minutes to form a stable Pickering foam template. Subsequently, 1.5 g AMPS, 0.3 g MBA, 0.05 g APS, and 0.05 g SBS were added, and the stirring, polymerization, and post-treatment conditions were the same as in Example 1 to obtain a porous antibacterial adsorbent material.
[0028] Comparative Example 2 This comparative example illustrates the effect of the order of zinc oxide addition on the material structure and properties. Under the same raw material composition and dosage conditions as Example 2, a control sample was prepared using the exact same process as Comparative Example 1, adding ZnO after foam formation. In this sample, zinc oxide also failed to achieve interfacial enrichment.
[0029] Performance testing 1. Structural characterization: Figure 1 Polarized light microscopy images of Pickering foams formed with different amounts of attapulgite and the corresponding bubble size distributions are shown. With increasing attapulgite content, the bubble size distribution narrows, uniformity improves, and the average size decreases, indicating that attapulgite has a significant regulatory and stabilizing effect on the foam structure.
[0030] Figure 2 Scanning electron microscope (SEM) images of the materials prepared in Examples 1 and 2 and the comparative examples are shown. The results show that all samples exhibit a three-dimensional interconnected macroporous structure, confirming the successful pore creation using the foam template method. At high magnification... Figure 2 In the df (data sample), the microstructure of the pore wall surface can be observed. When the zinc oxide content is low (e.g., 5%), the pore wall is mainly composed of fibrous attapulgite; when the zinc oxide content is increased to 10% (Example 1) and 15% (Example 2), a large number of zinc oxide particles are seen to be enriched on the pore wall surface, even forming a continuous particle layer. In contrast, the pore wall surface of the comparative sample (not shown) is relatively smooth, with fewer zinc oxide particles, confirming that the zinc oxide is mainly located inside the material.
[0031] 2. Ammonia nitrogen adsorption performance: The material obtained in Example 1 was subjected to ammonia nitrogen adsorption tests. At room temperature, its adsorption of NH4+ in water was measured. + The equilibrium adsorption capacity can reach 2.4 mmol / g. Figure 3 The adsorption rate curve of this material shows that it has a fast adsorption rate and a high adsorption capacity. This is attributed to the well-developed three-dimensional interconnected pore structure of the material and the excellent ammonia nitrogen adsorption capacity of attapulgite itself.
[0032] 3. Antibacterial properties: The plate count method was used to test the inhibition rate of the materials obtained in Examples 1 and 2 and Comparative Examples 1 and 2 against Escherichia coli and Staphylococcus aureus. The results are shown in Table 1.
[0033] Table 1 Comparison of antibacterial properties of different samples As shown in Table 1, the materials prepared in Examples 1 and 2 of this invention exhibited significantly better antibacterial effects against both test strains than their comparative counterparts. In particular, Example 2, with a zinc oxide content of 15%, showed an inhibition rate of up to 97.47% against *Escherichia coli*. This strongly demonstrates that by controlling the interface to enrich zinc oxide on the pore wall surface, its contact efficiency with microorganisms can be greatly improved, thereby significantly enhancing the antibacterial properties of the material.
[0034] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.
Claims
1. A porous antibacterial adsorbent and its preparation method, characterized in that, Includes the following steps: S1. Disperse surfactants, polymeric additives, attapulgite, and zinc oxide in water to form a uniform suspension; S2. Mechanically stir the suspension obtained in step S1 to introduce gas and form Pickering foam stabilized by attapulgite and zinc oxide particles. S3. Add polymerizable monomers, crosslinking agents and initiators to the Pickering foam obtained in step S2, mix them evenly, and carry out a polymerization reaction under heating conditions to solidify the foam structure and form a porous material with a three-dimensional interconnected pore structure. S4. The porous material obtained in step S3 is washed and dried to obtain the porous antibacterial adsorbent.
2. The porous antibacterial adsorbent and its preparation method according to claim 1, characterized in that: In step S1, the surfactant is one or more of hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, Tween surfactants, or saponins; the polymeric auxiliaries are one or more of chitosan, sodium alginate, polyvinyl alcohol, or polyacrylamide.
3. The porous antibacterial adsorbent and its preparation method according to claim 1, characterized in that: The components in step S1, by mass percentage, are: surfactant 0.2%–1.0%, polymeric additive 1.0%–3.0%, attapulgite 1.0%–10.0%, zinc oxide 5.0%–15.0%, with the remainder being water.
4. The porous antibacterial adsorbent and its preparation method according to claim 1, characterized in that: In step S2, the mechanical stirring speed is 3000-6000 rpm, and the stirring time is 10-20 minutes; the gas volume fraction of the resulting Pickering foam is 50%-90%.
5. The porous antibacterial adsorbent and its preparation method according to claim 1, characterized in that: In step S3, the polymerizable monomer is one or more of 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, or acrylamide; the crosslinking agent is N,N′-methylenebisacrylamide; and the initiator is a redox initiation system composed of ammonium persulfate and sodium bisulfite.
6. The porous antibacterial adsorbent and its preparation method according to claim 1, characterized in that: In step S3, the amount of polymerizable monomer added is 10% to 30% of the total mass of the system, the amount of crosslinking agent added is 20% to 30% of the monomer mass, and the amount of initiator added is 0.2% to 5% of the total mass of the system.
7. The porous antibacterial adsorbent and its preparation method according to claim 1, characterized in that: In step S3, the polymerization reaction is carried out at a temperature of 50–70°C for 6–12 hours.
8. A porous antibacterial adsorbent, characterized in that, The porous antibacterial adsorbent, prepared by any one of claims 1 to 7, has a three-dimensional interconnected pore structure formed by a Pickering foam template, and the zinc oxide antibacterial component is enriched and distributed in the pore wall surface area.