A piezoelectric composite fiber membrane having a persistent oil-water separation ability and biodegradability
Patent Information
- Application Number
- CN202611399301.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-10
- Publication Date
- 2026-10-30
AI Technical Summary
然而，传统聚合物材料的化学稳定性高，使其不可生物降解或不可再生
[0011]本发明提出了一种提高可生物降解的纤维膜材料油水分离能力的新策略，并以此制备一种具有持久油水分离能力的可生物降解的压电复合纤维膜材料，制备方法绿色环保、流程简易安全，在含油污水处理领域具有很好的应用价值。
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Abstract
Description
Technical Field
[0001] This invention relates to an oil-water separation membrane material, specifically to a biodegradable piezoelectric composite fiber membrane with durable oil-water separation capability and its preparation method, belonging to the field of new materials technology. Background Technology
[0002] With the acceleration of global industrialization, petrochemical and other fields generate large amounts of oily wastewater. Its main components include alkanes, aromatic hydrocarbons, colloids, and asphaltenes. These substances easily adsorb at the oil-water interface, forming a high-strength rigid membrane, which in turn forms an oil-in-water emulsion, making demulsification and separation difficult. Simultaneously, oily wastewater often contains toxic substances and heavy metal ions. Direct discharge without treatment will directly lead to water pollution and environmental damage, hindering my country's sustainable development. Compared with traditional separation methods such as centrifugation, biological demulsification, and chemical demulsification, membrane separation methods have the advantages of high operational efficiency and superior separation performance. The core of membrane separation is the membrane material. Currently, existing membrane materials are broadly divided into two categories: organic polymer membranes and inorganic membranes. Among them, organic polymer membranes, such as polyvinylidene fluoride, polyacrylonitrile, and polyethylene terephthalate, are widely used in the field of oily wastewater treatment due to the availability of raw materials, good chemical stability, and high processability.
[0003] Currently, the mainstream strategy for membrane separation is to construct a superhydrophilic surface on the surface of a composite fiber membrane, thereby achieving the retention of oil droplets in the emulsion and selective permeation of the aqueous phase. For example, Panchan Dansawad et al. constructed a silica network framework using hydrolyzed tetraethoxysilane (TEOS) on the surface of a recycled polyethylene terephthalate / polyethylene glycol / silica composite membrane, forming a dynamic hydration layer, thus achieving high-efficiency antifouling performance against oil-water emulsions (J. Environ. Chem. Eng., 13(5), 117472 (2025).). However, during long-term operation, oil contaminants inevitably accumulate on the membrane surface, forming a blockage layer, eventually leading to a decrease in membrane separation flux or even complete blockage. Therefore, researchers have proposed introducing a charged layer on the membrane surface to inhibit oil droplet adhesion by utilizing the electrostatic repulsion of the same charge on the oil droplets (J. Membr. Sci., 624, 118950 (2021).). However, oil droplets carrying opposite charges in the emulsion neutralize the charge on the membrane surface during separation. Maintaining the charged layer on the membrane surface by applying an external voltage would significantly increase operating costs. In contrast, the piezoelectric effect can convert the minute mechanical energy generated by the continuous impact of water flow on the membrane surface into continuous charged energy, thus overcoming the charge neutralization problem of conventional charged membranes (J. Am. Chem. Soc., 146, 213306(2024).). However, the high chemical stability of traditional polymer materials makes them non-biodegradable or non-renewable. Whether incinerated or landfilled, the continuous accumulation of waste materials will still lead to environmental damage and add more pressure to ecosystems. In summary, to address the growing environmental concerns and sustainable development challenges, developing green membrane materials that combine high-efficiency oil-water separation performance with biodegradability has become an important research direction.
[0004] To address the aforementioned problems, this invention proposes a novel composite fiber membrane material that combines piezoelectricity and biodegradability. By introducing the piezoelectric effect into a superhydrophilic membrane material, a biodegradable piezoelectric composite fiber membrane with durable oil-water separation capability is prepared. This membrane material is composed of hydrophilic fibers, which primarily form water channels during the separation process. Through doping modification, the oleophilic fibers are endowed with piezoelectric properties, thereby promoting the directional transport of different types of charged oil droplets based on electrostatic attraction or repulsion generated on the macroscopic fiber surface. This enhances the membrane's self-cleaning function and improves the efficiency of oil droplet coalescence and demulsification. This membrane material can achieve durable and efficient separation of various complex oil-water emulsions, and its preparation process is simple and environmentally friendly, thus possessing extremely high application potential and market prospects. Summary of the Invention
[0005] The purpose of this invention is to propose a new strategy to improve the oil-water separation capability of biodegradable fiber membrane materials, and to prepare a biodegradable piezoelectric composite fiber membrane with durable oil-water separation capability.
[0006] The implementation process of this invention is briefly explained below. First, polycaprolactone (PCL) and glycine are selected as raw materials. The precursor solution is prepared by adjusting parameters, and barium titanate (BaTiO3) nanoparticles are doped into the PCL precursor solution. Then, a biodegradable hydrophilic composite fiber membrane material is prepared using electrospinning technology. Finally, the fiber membrane material is hydrophilically modified by tannic acid and 3-aminopropyltriethoxysilane (APTES) to enhance its affinity for water molecules. This fiber membrane not only achieves high-throughput oil-water separation due to its superhydrophilic surface, but also utilizes the piezoelectric response of the oleophilic fiber surface through water flow pulses. The electrostatic interaction between the fiber and oil droplets enables the directional transport of different charged oil droplets, enhancing the coalescence and demulsification performance of the fiber membrane. This allows for the sustained and efficient separation of various complex oil-water emulsions. Furthermore, the preparation method is simple, feasible, and environmentally friendly, thus showing great application potential.
[0007] This invention specifically relates to a biodegradable piezoelectric composite fiber membrane with durable oil-water separation capability and its preparation method, which is achieved through the following specific steps:
[0008] (1) Preparation of precursor solution: Barium titanate (16% of total solid mass), β-glycine crystals (3.5 wt%) and polycaprolactone (10.3 wt%) were dissolved in a solution of dichloromethane, N,N-dimethylacetamide and acetone (volume ratio 5.4:4.6:1) to prepare PCL precursor solution; the precursor mixture was magnetically stirred at 35 °C for 17~20 h to obtain a homogeneous precursor solution.
[0009] (2) High-speed electrospinning process: Take 5 mL of PCL precursor solution using a syringe and install a No. 22 stainless steel needle at the tip of the syringe. Place the syringe in the electrospinning equipment, set the injection pump speed to 0.5-0.6 mm / min, adjust the distance between the syringe needle and the roller receiver to 6-12 cm, and connect the syringe needles with a wire. Then, cover the roller receiver with a layer of aluminum foil and adjust the rotation speed of the roller receiver to 2800-4000 r / min. Connect the positive terminal of the high-voltage power supply to the syringe needle and adjust the voltage to 9-11 kV. Connect the negative terminal of the high-voltage power supply to the roller receiver and adjust the voltage to -1 to -2 kV. The spinning time lasts for 1-2 h. After spinning, remove the fiber membrane from the spinning machine.
[0010] (3) Hydrophilic modification process: Tannic acid (0.2 wt%) was placed in deionized water and Tris-dilute hydrochloric acid buffer (volume ratio 200:2) and stirred evenly; then 3-aminopropyltriethoxysilane (APTES, 0.2 wt%) was added to the solution and stirred evenly to obtain a hydrophilic modified solution. The fiber membrane obtained by electrospinning was immersed in the above modified solution and placed in a shaker for 8-10 h to obtain a superhydrophilic composite piezoelectric fiber membrane.
[0011] This invention proposes a novel strategy to improve the oil-water separation capability of biodegradable fiber membrane materials, and uses this strategy to prepare a biodegradable piezoelectric composite fiber membrane material with durable oil-water separation capability. The preparation method is green and environmentally friendly, and the process is simple and safe, which has great application value in the field of oily wastewater treatment. Attached Figure Description
[0012] Figure 1 is a scanning electron microscope image of the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 provided according to the present invention.
[0013] Figure 2 is a comparison image of the output voltage of the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 provided according to the present invention.
[0014] Figure 3 shows a comparison of the separation performance of the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 provided according to the present invention.
[0015] Figure 4 shows a biodegradation image of the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 provided according to the present invention. Detailed Implementation
[0016] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0017] Example 1
[0018] First, the precursor solution was prepared: barium titanate (16% of total solid mass), β-glycine crystals (3.5 wt%) and polycaprolactone (10.3 wt%) were dissolved in a solution of dichloromethane, N,N-dimethylacetamide and acetone (volume ratio 5.4 : 4.6 : 1) to prepare the PCL precursor solution; the precursor mixture was magnetically stirred at 35 ℃ for 17~20 h to obtain a homogeneous precursor solution.
[0019] Then, the high-speed electrospinning process is performed as follows: 5 mL of PCL precursor solution is taken using a syringe, and a 22-gauge stainless steel needle is attached to the tip of the syringe. The syringe is placed in the electrospinning equipment, and the injection pump speed is set to 0.5–0.6 mm / min. The distance between the syringe needle and the roller receiver is adjusted to 6–12 cm, and the syringe needle is connected using a wire. Subsequently, an aluminum foil is wrapped around the roller receiver, and the rotation speed of the roller receiver is adjusted to 2800–4000 r / min. The positive terminal of the high-voltage power supply is connected to the syringe needle, and the voltage is adjusted to 9–11 kV. The negative terminal of the high-voltage power supply is connected to the roller receiver, and the voltage is adjusted to -1 to -2 kV. The spinning time is 1–2 h. After spinning, the fiber membrane is removed from the spinning machine.
[0020] Finally, the hydrophilic modification process was performed as follows: Tannic acid (0.2 wt%) was placed in deionized water and Tris-dilute hydrochloric acid buffer (volume ratio 200:2) and stirred until homogeneous; then 3-aminopropyltriethoxysilane (APTES, 0.2 wt%) was added to the solution and stirred thoroughly to obtain a hydrophilic modified solution. The fiber membrane obtained by electrospinning was immersed in the above modified solution and placed in a shaker for 8-10 h to obtain a superhydrophilic composite piezoelectric fiber membrane.
[0021] Figure 1 Scanning electron microscope (SEM) images of the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 constructed in this invention are provided. The images clearly show that the PCL / Glycine@BaTiO3 fibers have a rough surface, uniformly adhered with a large number of barium titanate nanoparticles, and locally contain a small number of filler agglomerates and protrusions. The diameters of the two types of fibers are basically the same, approximately 400–480 nm, and the fibers are uniformly distributed in an interwoven pattern, forming a continuous porous network.
[0022] Figure 2 The output piezoelectricity diagrams of barium titanate in the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 according to the present invention at different doping concentrations are presented. As shown in the figure, the output voltage first increases and then decreases with increasing barium titanate doping concentration, reaching a peak at a doping concentration of 16% of the total solid mass.
[0023] Figure 3 The separation flux and separation efficiency of the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 according to the present invention are shown in different oil phases. As shown in the figure, the separation flux and separation efficiency decrease with increasing oil phase viscosity, while the separation efficiency remains above 95%, indicating that the product fiber membrane has good separation efficiency and can meet the requirements of practical applications.
[0024] Figure 4A comparison of the degradation process of the biodegradable piezoelectric fiber membrane PCL / Glycine@BaTiO3 provided according to this invention in soil with that of commercially available PAN fiber membranes is presented. As shown in the figure, the PCL / Glycine@BaTiO3 fiber membrane naturally degraded and fragmented in soil within 30 days, and was completely degraded within 90 days; while the PAN fiber membrane showed no tendency to degrade in the natural environment. The results indicate that the biodegradable piezoelectric fiber membrane prepared by this invention possesses excellent biodegradability and has significant application value in the field of green treatment of oily wastewater.
Claims
1. This invention specifically relates to a piezoelectric composite fiber membrane with durable oil-water separation capability and biodegradability, and a method for preparing the same. The method is as follows: (1) Preparation of precursor solution: Barium titanate (16% of total solid mass), β-glycine crystals (3.5 wt%) and polycaprolactone (10.3 wt%) were dissolved in a solution of dichloromethane, N,N-dimethylacetamide and acetone (volume ratio 5.4:4.6:1) to prepare PCL precursor solution; the precursor mixture was magnetically stirred at 35 °C for 17~20 h to obtain a homogeneous precursor solution; (2) High-speed electrospinning process: Take 5 mL of PCL precursor solution using a syringe and install a No. 22 stainless steel needle at the tip of the syringe. Place the syringe in the electrospinning equipment, set the injection pump speed to 0.5-0.6 mm / min, adjust the distance between the syringe needle and the roller receiver to 6-12 cm, and connect the syringe needles with a wire. Then, cover the roller receiver with a layer of aluminum foil and adjust the rotation speed of the roller receiver to 2800-4000 r / min. Connect the positive terminal of the high-voltage power supply to the syringe needle and adjust the voltage to 9-11 kV. Connect the negative terminal of the high-voltage power supply to the roller receiver and adjust the voltage to -1--2 kV. The spinning time lasts for 1-2 h. After spinning, remove the fiber membrane from the spinning machine. (3) Hydrophilic modification process: Tannic acid (0.2 wt%) was placed in deionized water and Tris-dilute hydrochloric acid buffer (volume ratio 200:2) and stirred evenly; then 3-aminopropyltriethoxysilane (APTES, 0.2 wt%) was added to the solution and stirred evenly to obtain a hydrophilic modified solution. The fiber membrane obtained by electrospinning was immersed in the above modified solution and placed in a shaker for 8-10 h to obtain a superhydrophilic composite piezoelectric fiber membrane; The research results show that the biodegradable piezoelectric fiber membrane prepared by this invention has efficient and long-lasting oil-water separation capabilities, and the preparation method is simple, safe, green and environmentally friendly, which has great application value in the field of oily wastewater treatment.