A preparation method of rare earth-based biomimetic mineralized super-hydrophilic material
By constructing a rare earth-based adhesion layer and a mineralized layer on a polymer substrate, the problems of the polymer substrate being susceptible to oil contamination and material instability are solved, and a stable super-hydrophilic coating is achieved, which is suitable for efficient oil-water separation in commercial separation membranes and separation networks.
Patent Information
- Application Number
- CN202310621614.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-29
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2043-05-29
AI Technical Summary
The polymer substrate of existing oil-water separation materials is easily contaminated by oil, resulting in a decrease in separation flux and efficiency. In addition, commonly used mineralized layer materials are unstable or toxic under acidic and alkaline conditions, which increases costs.
A rare earth-based adhesion layer is constructed on a polymer substrate by utilizing the coordination effect of tannic acid and rare earth ions, and a mineralized layer is formed by the deposition of rare earth phosphates to form a stable super-hydrophilic coating, which is suitable for commercial separation membranes and separation networks.
The method achieves stable and efficient oil-water separation in different pH and salt solutions. It is easy to operate, low-cost, suitable for large-scale production, and the precursor solution can be used multiple times.
Smart Images
Figure CN116531965B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of super-hydrophilic coating preparation, and in particular to a method for preparing a rare earth-based biomimetic mineralized super-hydrophilic material. Background Art
[0002] Daily life, industrial production and crude oil spills all generate a large amount of oily wastewater. These insoluble oils enter the natural environment in the form of mixtures and emulsions, greatly affecting life safety and ecological environmental health. There is an urgent need to develop efficient oil-water separation technology.
[0003] Membrane separation technology has become a leader in oil-water separation technology due to its high separation efficiency, good energy utilization and low operating cost. Commonly used polymer substrates are hydrophobic and oleophilic, and are easily contaminated by oil, resulting in problems such as decreased separation flux and decreased separation efficiency, so surface modification is required. Superhydrophilic and underwater superoleophobic coatings, as a low-cost and convenient anti-oil technology, are used for surface modification of separation materials. Hydrophilic hydrogels or polyelectrolyte molecular brushes are usually used to introduce polymer substrates by grafting or blending to obtain a hydration layer on the polymer surface to achieve underwater anti-fouling effects. However, the soft polymer surface is easily affected by external forces and mechanically deformed, which affects the separation performance and anti-fouling effect during long-term use.
[0004] Based on this situation and inspired by the excellent antifouling capabilities of marine organisms, hydrophilic and durable mineralized coatings are being applied to the modification of oil-water separation materials. However, these mineralized layers are typically composed of substances such as calcium carbonate, iron oxide, titanium oxide, and silicon oxide. Materials such as calcium carbonate and iron oxide are unstable in acidic or alkaline conditions, causing the coating to fail. Materials such as titanium oxide and silicon oxide typically use unstable and toxic alkyl ester precursors, requiring long reaction times and limiting the ability to reuse the reaction solution, increasing the cost of industrialization. Summary of the Invention
[0005] In response to the shortcomings of the prior art, the present invention provides a method for preparing a rare earth-based biomimetic mineralized superhydrophilic material. The present invention utilizes the coordination effect of tannic acid and rare earth ions to achieve stable adhesion on a variety of polymer substrates, and uses this as a nucleation site to induce further deposition of low-solubility rare earth phosphates. The superhydrophilic coating prepared by the present invention has excellent separation efficiency and underwater antifouling performance, high stability in different pH and salt solutions, simple operation method, and is applicable to common commercial separation membranes and separation nets, taking into account both separation efficiency and antifouling performance, and is inexpensive and universal.
[0006] The technical solutions of the present invention are as follows:
[0007] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a substrate, a rare earth-based adhesion layer and a rare earth-based mineralized layer sequentially arranged on the surface of the substrate.
[0008] Furthermore, the rare earth-based biomimetic mineralized super-hydrophilic material includes a rare earth-based biomimetic mineralized super-hydrophilic coating, and the super-hydrophilic coating includes a rare earth-based adhesion layer and a rare earth-based mineralized layer.
[0009] Furthermore, the rare earth-based adhesion layer is formed by tannic acid and rare earth ions assembling at the interface. The interface refers to the solid-liquid interface between the substrate and the infiltration solution. Due to the two-step infiltration, electrostatic adsorption controls the assembly of tannic acid and rare earth ions only at the interface.
[0010] Furthermore, the rare earth-based mineralized layer is a sparingly soluble rare earth phosphate.
[0011] Furthermore, the rare earth element of the rare earth base includes but is not limited to one of lanthanum, cerium, and neodymium. Preferably, the rare earth element of the rare earth base is lanthanum.
[0012] Furthermore, the substrate is a polymer substrate, the polymer substrate includes a separation membrane or a separation network, the material of the polymer substrate includes one or more of polyvinylidene fluoride, nylon, and polyethersulfone; and the polymer substrate is a hydrophobic material.
[0013] A method for preparing the rare earth-based biomimetic mineralized super-hydrophilic material comprises the following steps:
[0014] S1: soaking the polymer substrate with ethanol, taking it out, dipping it in a tannic acid solution, taking it out again, rinsing it, dipping it in a rare earth salt solution, taking it out again, rinsing it, and drying it to obtain a modified polymer;
[0015] S2: After immersing the modified polymer obtained in step S1 in a rare earth salt solution, taking it out and rinsing it, then immersing it in a phosphate solution, taking it out and rinsing it, repeating the above rare earth salt solution immersion, rinsing, and phosphate solution immersion and rinsing process, and then drying it to obtain a rare earth-based biomimetic mineralized super hydrophilic material.
[0016] Furthermore, in step S1, the polymer substrate includes a separation membrane or a separation net, and the material of the polymer substrate includes one of polyvinylidene fluoride, nylon, and polyethersulfone.
[0017] Furthermore, in steps S1 and S2, the rare earth salt is a soluble rare earth salt. Preferably, the rare earth salt is lanthanum chloride, and the concentration of the rare earth salt solution is 0.05-0.5 mol / L.
[0018] Furthermore, in step S1, the concentration of the tannic acid solution is 1-10 mg / L; and the immersion time is 0.5-2 h.
[0019] Furthermore, in step S2, the phosphate is a soluble phosphate, preferably, the phosphate is sodium dihydrogen phosphate or disodium hydrogen phosphate, and the concentration of the phosphate solution is 0.05-0.5 mol / L; the immersion time is 1-5 min, and the number of cycles is 1-10 times.
[0020] The present invention also protects a rare earth-based biomimetic mineralized super-hydrophilic coating, which is formed on the surface of a substrate and includes a rare earth-based adhesion layer and a rare earth-based mineralized layer. The rare earth-based biomimetic mineralized super-hydrophilic material includes a rare earth-based biomimetic mineralized super-hydrophilic coating, which includes a rare earth-based adhesion layer and a rare earth-based mineralized layer. The rare earth-based adhesion layer is obtained by assembling tannic acid and rare earth ions at the interface. The rare earth-based mineralized layer is a sparingly soluble rare earth phosphate. The rare earth element of the rare earth base includes but is not limited to one of lanthanum, cerium, and neodymium. Preferably, the rare earth element of the rare earth base is lanthanum.
[0021] The rare earth-based biomimetic mineralized super-hydrophilic coating is used for oil-water separation.
[0022] The beneficial technical effects of the present invention are:
[0023] This invention leverages the strong interaction between tannic acid and rare earth ions to construct hydrophilic coatings on various polymer surfaces. These coatings serve as nucleation sites, inducing the nucleation and growth of rare earth phosphates. Due to the extremely low solubility and mechanical stability of rare earth phosphates, the resulting super-hydrophilic coatings are stable in various pH and saline solutions and exhibit high separation efficiency for various oil-water emulsions and mixtures.
[0024] The present invention utilizes a sparingly soluble rare earth phosphate as a hydrophilic functional layer for the first time, providing stable underwater superoleophobic properties in complex acidic, alkaline and salt environments; the entire process is based entirely on aqueous dip coating, is pollution-free, low-energy, and the precursor solution can be recycled; the process method can quickly obtain a stable superhydrophilic coating through simple cyclic immersion, is easy to operate, and has high repeatability. The precursor salt solution used can be used multiple times in different batches of products, and has low selectivity for polymer substrates. It is an inexpensive, easy to mass-produce, and popularizable preparation technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 These are digital photos of the rare earth-based biomimetic mineralized super-hydrophilic coating modified polymer separation membrane and separation network prepared in Examples 2 and 5.
[0026] Figure 2These are microscopic photos of the rare earth-based biomimetic mineralized super-hydrophilic coating modified polymer separation membrane prepared in Example 2 before and after separation of oil-water emulsion.
[0027] Figure 3 This is a digital photo of the rare earth-based biomimetic mineralized super-hydrophilic coating modified polymer separation network prepared in Example 5 separating an oil-water mixture.
[0028] In the figure: A, is before the separation test starts, B, is during the separation test, and C, shows the end of the separation test.
[0029] Figure 4 The oil-water emulsion separation performance of the rare earth-based biomimetic mineralized super-hydrophilic coating modified polymer separation membrane prepared in Examples 1-3 and Comparative Example 1 under different cyclic immersion times.
[0030] Figure 5 This is the multiple cycle separation experiment of Example 2.
[0031] Figure 6 The underwater oil contact angles measured in Example 2 after immersion in solutions with different pH values for 24 hours.
[0032] Figure 7 The underwater oil contact angles measured in Example 2 after immersion in different salt solutions for 7 days.
[0033] Figure 8 This is the underwater oil contact angle of various oil droplets in Example 2.
[0034] Figure 9 These are digital photos of Example 2 and Comparative Example 2 before and after oil droplet flushing. DETAILED DESCRIPTION
[0035] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.
[0036] The invention discloses a rare earth-based biomimetic mineralized super-hydrophilic material. The rare earth-based biomimetic mineralized super-hydrophilic material comprises a substrate, a rare earth-based adhesion layer and a rare earth-based mineralized layer which are sequentially arranged on the surface of the substrate.
[0037] In one embodiment of the present invention, the rare earth-based adhesion layer is obtained by assembling tannic acid and rare earth ions at the interface.
[0038] In one embodiment of the present invention, the rare earth-based mineralized layer is a sparingly soluble rare earth phosphate.
[0039] In one embodiment of the present invention, the rare earth element of the rare earth base includes but is not limited to one of lanthanum, cerium, and neodymium.
[0040] In one embodiment of the present invention, the rare earth element of the rare earth base is preferably lanthanum.
[0041] In one embodiment of the present invention, the substrate is a polymer substrate.
[0042] A method for preparing the rare earth-based biomimetic mineralized super-hydrophilic material comprises the following steps:
[0043] S1: soaking the polymer substrate with ethanol, taking it out, dipping it in a tannic acid solution, taking it out again, rinsing it, dipping it in a rare earth salt solution, taking it out again, rinsing it, and drying it to obtain a modified polymer;
[0044] S2: After immersing the modified polymer obtained in step S1 in a rare earth salt solution, taking it out and rinsing it, then immersing it in a phosphate solution, taking it out and rinsing it, repeating the above rare earth salt solution immersion, rinsing, and phosphate solution immersion and rinsing process, and then drying it to obtain a rare earth-based biomimetic mineralized super hydrophilic material.
[0045] In one embodiment of the present invention, in step S1, the polymer substrate comprises a separation membrane or a separation net, and the material of the polymer substrate is one or more of polyvinylidene fluoride, nylon or polyethersulfone.
[0046] In one embodiment of the present invention, in steps S1 and S2, the rare earth salt is a soluble rare earth salt. Preferably, the rare earth salt is lanthanum chloride, and the concentration of the rare earth salt solution is 0.05 mol / L, 0.1 mol / L, 0.2 mol / L or 0.5 mol / L.
[0047] In one embodiment of the present invention, in step S1, the concentration of the tannic acid solution is 1 mg / L, 2 mg / L, 5 mg / L, 8 mg / L or 10 mg / L; and the immersion time is 0.5 h, 1 h, 1.5 h or 2 h.
[0048] In one embodiment of the present invention, in step S2, the phosphate is a soluble phosphate, preferably, the phosphate is sodium dihydrogen phosphate or disodium hydrogen phosphate, and the concentration of the phosphate solution is 0.05 mol / L, 0.1 mol / L, 0.2 mol / L or 0.5 mol / L; the immersion time is 1 min, 2 min, 4 min or 5 min, and the number of cycles is 1 time, 2 times, 4 times, 8 times or 10 times.
[0049] The present invention also uses the rare earth-based biomimetic mineralized super-hydrophilic material for oil-water separation.
[0050] In the present invention, the oil-water separation experiment is conducted by a dead-end filtration device experiment, and the oil content is determined by an organic carbon analyzer.
[0051] The present invention will be further described below through examples and comparative examples.
[0052] Example 1
[0053] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a rare earth-based adhesion layer and a rare earth-based mineralized layer; the rare earth-based adhesion layer is formed by assembling tannic acid and rare earth ions at the interface; the rare earth-based mineralized layer is a rare earth phosphate; and the rare earth element of the rare earth base is lanthanum. The preparation process of the rare earth-based biomimetic mineralized super-hydrophilic material is as follows:
[0054] S1, polyvinylidene fluoride microporous filter membrane (such as Figure 1 The adhesive layer (shown) was pre-soaked with ethanol, removed, and then immersed in a 10 mg / L tannic acid solution for 1 hour. After rinsing, it was immersed in a 0.1 mol / L lanthanum chloride solution for 30 minutes. After rinsing, it was dried to obtain an adhesive layer-modified polymer. (Polyphenols provide hydrogen bonds, which strongly interact with rare earth ions.)
[0055] S2, the gained modified polymer is immersed in 0.1mol / L lanthanum chloride solution for 5min, takes out and rinses and immerses in 0.1mol / L sodium dihydrogen phosphate solution for 5min, takes out and rinses, this is recorded as one soaking cycle. Soak 2 cycles and then dry to obtain a polymer modified by rare earth-based biomimetic mineralization super-hydrophilic coating, that is, rare earth-based biomimetic mineralization super-hydrophilic material.
[0056] Among them, a rare earth-based biomimetic mineralized super-hydrophilic coating is formed on the surface of the substrate.
[0057] Example 2
[0058] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a rare earth-based adhesion layer and a rare earth-based mineralized layer; the rare earth-based adhesion layer is formed by assembling tannic acid and rare earth ions at the interface; the rare earth-based mineralized layer is a rare earth phosphate; and the rare earth element of the rare earth base is lanthanum. The preparation process of the rare earth-based biomimetic mineralized super-hydrophilic material is as follows:
[0059] S1. Pre-soak the polyvinylidene fluoride microporous filter membrane with ethanol, take it out, and then immerse it in a 10 mg / L tannic acid solution for 1 hour. After taking it out and rinsing it, immerse it in a 0.1 mol / L lanthanum chloride solution for 30 minutes. Take it out, rinse it, and dry it to obtain an adhesion layer modified polymer.
[0060] S2, the gained modified polymer is immersed in 0.1mol / L lanthanum chloride solution for 5min, takes out and rinses and then immerses in 0.1mol / L sodium dihydrogen phosphate solution for 5min, takes out and rinses, this is recorded as one soaking cycle. Soaking 4 cycles and then drying to obtain a polymer modified by rare earth-based biomimetic mineralization super-hydrophilic coating, that is, rare earth-based biomimetic mineralization super-hydrophilic material.
[0061] Among them, a rare earth-based biomimetic mineralized super-hydrophilic coating is formed on the surface of the substrate.
[0062] Example 3
[0063] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a rare earth-based adhesion layer and a rare earth-based mineralized layer; the rare earth-based adhesion layer is formed by assembling tannic acid and rare earth ions at the interface; the rare earth-based mineralized layer is a rare earth phosphate; and the rare earth element of the rare earth base is lanthanum. The preparation process of the rare earth-based biomimetic mineralized super-hydrophilic material is as follows:
[0064] S1. Pre-soak the polyvinylidene fluoride microporous filter membrane with ethanol, take it out, and then immerse it in a 10 mg / L tannic acid solution for 1 hour. After taking it out and rinsing it, immerse it in a 0.1 mol / L lanthanum chloride solution for 30 minutes. Take it out, rinse it, and dry it to obtain an adhesion layer modified polymer.
[0065] S2, the gained modified polymer is immersed in 0.1mol / L lanthanum chloride solution for 5min, takes out and rinses and then immerses in 0.1mol / L sodium dihydrogen phosphate solution for 5min, takes out and rinses, this is recorded as one soaking cycle. Soaking and drying after 6 cycles obtain the polymer modified by rare earth-based biomimetic mineralization super-hydrophilic coating, that is, rare earth-based biomimetic mineralization super-hydrophilic material.
[0066] Among them, a rare earth-based biomimetic mineralized super-hydrophilic coating is formed on the surface of the substrate.
[0067] Example 4
[0068] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a rare earth-based adhesion layer and a rare earth-based mineralized layer; the rare earth-based adhesion layer is formed by assembling tannic acid and rare earth ions at the interface; the rare earth-based mineralized layer is a rare earth phosphate; and the rare earth element of the rare earth base is lanthanum. The preparation process of the rare earth-based biomimetic mineralized super-hydrophilic material is as follows:
[0069] S1. Pre-soak the polyvinylidene fluoride microporous filter membrane with ethanol, take it out, and then immerse it in a 10 mg / L tannic acid solution for 1 hour. After taking it out and rinsing it, immerse it in a 0.1 mol / L lanthanum chloride solution for 30 minutes. Take it out, rinse it, and dry it to obtain an adhesion layer modified polymer.
[0070] S2, the gained modified polymer is immersed in 0.1mol / L lanthanum chloride solution for 5min, takes out and rinses and then immerses in 0.1mol / L sodium dihydrogen phosphate solution for 5min, takes out and rinses, this is recorded as one immersion cycle. Soak 8 cycles and then dry to obtain a polymer modified by rare earth-based biomimetic mineralization super-hydrophilic coating, that is, rare earth-based biomimetic mineralization super-hydrophilic material.
[0071] Among them, a rare earth-based biomimetic mineralized super-hydrophilic coating is formed on the surface of the substrate.
[0072] Example 5
[0073] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a rare earth-based adhesion layer and a rare earth-based mineralized layer; the rare earth-based adhesion layer is formed by assembling tannic acid and rare earth ions at the interface; the rare earth-based mineralized layer is a rare earth phosphate; and the rare earth element of the rare earth base is lanthanum. The preparation process of the rare earth-based biomimetic mineralized super-hydrophilic material is as follows:
[0074] S1. Pre-soak a 300-mesh nylon mesh with ethanol, remove it, and then immerse it in a 10 mg / L tannic acid solution for 1 hour. Remove it, rinse it, and then immerse it in a 0.1 mol / L lanthanum chloride solution for 30 minutes. Remove it, rinse it, and dry it to obtain an adhesion layer modified polymer.
[0075] S2, the gained modified polymer is immersed in 0.1mol / L lanthanum chloride solution for 5min, takes out and rinses and then immerses in 0.1mol / L sodium dihydrogen phosphate solution for 5min, takes out and rinses, this is recorded as one soaking cycle. Soaking 4 cycles and then drying to obtain a polymer modified by rare earth-based biomimetic mineralization super-hydrophilic coating, that is, rare earth-based biomimetic mineralization super-hydrophilic material.
[0076] Among them, a rare earth-based biomimetic mineralized super-hydrophilic coating is formed on the surface of the substrate.
[0077] Example 6
[0078] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a rare earth-based adhesion layer and a rare earth-based mineralized layer; the rare earth-based adhesion layer is formed by assembling tannic acid and rare earth ions at the interface; the rare earth-based mineralized layer is a rare earth phosphate; and the rare earth element of the rare earth base is lanthanum. The preparation process of the rare earth-based biomimetic mineralized super-hydrophilic material is as follows:
[0079] S1, nylon (such as Figure 1 The adhesive layer (shown) was pre-soaked with ethanol, removed, and then immersed in a 1 mg / L tannic acid solution for 2 hours. After removal and rinsing, it was immersed in a 0.05 mol / L lanthanum chloride solution for 30 minutes. After removal, rinsing, and drying, a modified polymer adhesive layer was obtained. (Polyphenols provide hydrogen bonds and have strong interactions with rare earth ions.)
[0080] S2, the modified polymer was immersed in a 0.05mol / L lanthanum chloride solution for 5min, taken out and rinsed, and then immersed in a 0.05mol / L sodium dihydrogen phosphate solution for 1min, taken out and rinsed. This was recorded as one soaking cycle. After soaking for 10 cycles, the polymer was dried to obtain a rare earth-based biomimetic mineralized super-hydrophilic coating modified polymer, that is, a rare earth-based biomimetic mineralized super-hydrophilic material.
[0081] Among them, a rare earth-based biomimetic mineralized super-hydrophilic coating is formed on the surface of the substrate.
[0082] Example 7
[0083] A rare earth-based biomimetic mineralized super-hydrophilic material comprises a rare earth-based adhesion layer and a rare earth-based mineralized layer; the rare earth-based adhesion layer is formed by assembling tannic acid and rare earth ions at the interface; the rare earth-based mineralized layer is a rare earth phosphate; and the rare earth element of the rare earth base is lanthanum. The preparation process of the rare earth-based biomimetic mineralized super-hydrophilic material is as follows:
[0084] S1. Pre-soak the polyethersulfone with ethanol, remove it, and then immerse it in a 5 mg / L tannic acid solution for 0.5 h. Remove it, rinse it, and then immerse it in a 0.5 mol / L lanthanum chloride solution for 30 min. Remove it, rinse it, and dry it to obtain an adhesive layer-modified polymer. (Polyphenols provide hydrogen bonds and have strong interactions with rare earth ions.)
[0085] S2, the modified polymer was immersed in a 0.5 mol / L lanthanum chloride solution for 5 min, taken out and rinsed, and then immersed in a 0.5 mol / L disodium hydrogen phosphate solution for 3 min, taken out and rinsed. This was recorded as one soaking cycle. After soaking for 1 cycle, the polymer was dried to obtain a rare earth-based biomimetic mineralized super-hydrophilic coating modified polymer, that is, a rare earth-based biomimetic mineralized super-hydrophilic material.
[0086] Among them, a rare earth-based biomimetic mineralized super-hydrophilic coating is formed on the surface of the substrate.
[0087] Comparative Example 1
[0088] The polyvinylidene fluoride microporous filter membrane was pre-soaked, then immersed in a 10 mg / L tannic acid solution for 1 hour, removed and rinsed, and then immersed in a 0.1 mol / L lanthanum chloride solution for 30 minutes, removed and rinsed, and dried.
[0089] Properties: Non-mineralized modified separation membranes cannot achieve underwater superoleophobicity and are easily contaminated by oil.
[0090] Comparative Example 2
[0091] Pre-soak the polyvinylidene fluoride microporous filter membrane with ethanol, immerse it in a 0.1 mol / L lanthanum chloride solution for 5 minutes, remove it, rinse it, and then immerse it in a 0.1 mol / L sodium dihydrogen phosphate solution for 5 minutes. Remove it and rinse it. This is recorded as one immersion cycle. After 4 immersion cycles, dry it.
[0092] Properties: Hydrophobic polymer substrates cannot be directly modified by biomimetic mineralization.
[0093] Test example:
[0094] The rare earth-based biomimetic mineralized super-hydrophilic coating modified polymer separation membrane prepared in Example 2 was used to separate the oil-water emulsion. Specifically, the membrane material was placed in a dead-end filtration device and dead-end filtration was performed under a vacuum pressure of 0.3 bar. Microscopic photographs before and after separation were taken. The results are shown in FIG. Figure 2As shown in the figure, it can be seen that when the separation membrane prepared in Example 2 is used to separate n-hexane and pump oil, there are obvious emulsion droplets before separation, but no obvious emulsion droplets after separation.
[0095] The separation efficiency and cycle number of the membranes prepared in the examples and comparative examples were tested. The specific experimental method was as follows: a xylene emulsion stabilized with Tween 80 (oil-water ratio 1:99) was used as the separation liquid, and the separation membrane was pre-soaked and placed in a dead-end filtration device (device as shown in FIG. Figure 3 As shown, Figure A shows before the separation test, Figure B shows during the separation test, and Figure C shows the end of the separation test). Filtration was performed under a vacuum pressure of 0.3 bar, and the separation flux was calculated using the filtration time and filtration volume. The filtrate was tested by a TOC analyzer to calculate the separation efficiency.
[0096] Figure 4 The oil-water emulsion separation performance of the rare earth-based biomimetic mineralized super-hydrophilic coating-modified polymer separation membranes prepared in Examples 1-3 and Comparative Example 1 at different immersion cycles is shown. As shown in the figure, Examples 1-3 show improvements in both separation flux and efficiency compared to Comparative Example 1. The difference in separation efficiency, particularly 99% versus 97%, is significant, indicating a 200% improvement in oil rejection (residual oil content reduced from 3% to 1%).
[0097] An emulsion was prepared at an oil-water ratio of 1:99, wherein the oil phase was a xylene emulsion stabilized with 1% Tween 80. The membrane material was placed in a dead-end filtration device, the emulsion was added, and dead-end filtration was performed under a vacuum pressure of 0.3 bar. The separation flux and separation efficiency of the membrane material prepared in Example 2 were measured for multiple cycles. The results are shown in FIG. Figure 5 As shown in Figure 2, for the first ten cycles, a fixed volume of emulsion was separated each time, followed by a brief water rinse after separation, and then continued testing. After ten cycles, the separation flux dropped to 85%, and the separation efficiency dropped to 97.6%, although these remained at a high level. After the tenth separation, a one-hour water backwash followed by further testing showed that the separation flux recovered to 99.5%, and the separation efficiency returned to 99.1%, demonstrating the excellent anti-fouling performance of Example 2.
[0098] The membrane material prepared in Example 2 was soaked in solutions of different pH values for 24 hours, then placed in water. A 4 μl oil droplet was injected onto the membrane surface with a microsyringe. The underwater oil contact angle was measured. The results are shown in Figure 2. Figure 6 As shown in the figure, it can be seen that the membrane prepared in Example 2 has excellent pH stability.
[0099] The membrane materials prepared in Example 2 were soaked in different salt solutions for seven days, and then placed in water. A 4 μl oil droplet was injected onto the membrane surface with a micro syringe. The underwater oil contact angle of the membrane material was measured. The results are as follows: Figure 7 As shown in the figure, it can be seen that the membrane material prepared by the present invention has excellent salt solution stability.
[0100] The membrane material prepared in Example 2 was placed in water, and a 4 μl oil droplet was injected onto the membrane surface with a micro syringe. The underwater oil contact angle of the membrane material prepared in Example 2 to various oil droplets was measured. The results are shown in FIG. Figure 8 As shown, it is demonstrated that the membrane prepared by the present invention has a broad spectrum of underwater oleophobicity.
[0101] The membrane materials of Example 2 and Comparative Example 2 were placed in water respectively, and 3 mL of xylene was drawn with a syringe and injected on the surface of the membrane material to test the surface of the membrane material before and after the oil droplet was flushed. Figure 9 As shown, under the flushing of oil droplets (dark color), the oil droplets adhere to Comparative Example 2, but not to Example 2, indicating that the membrane material prepared in Example 2 has excellent underwater oleophobicity.
[0102] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the scope of protection of the present invention.
Claims
1. A rare earth-based biomimetic mineralized super-hydrophilic material, characterized in that: The rare earth-based biomimetic mineralized super-hydrophilic material comprises a substrate, a rare earth-based adhesion layer and a rare earth-based mineralized layer sequentially arranged on the surface of the substrate; The rare earth-based adhesion layer is obtained by assembling tannic acid and rare earth ions at the interface; and the rare earth-based mineralization layer is rare earth phosphate.
2. The rare earth-based biomimetic mineralized super-hydrophilic material according to claim 1, characterized in that: The rare earth element of the rare earth base includes one of lanthanum, cerium and neodymium.
3. The rare earth-based biomimetic mineralized super-hydrophilic material according to claim 1, characterized in that: The rare earth element of the rare earth base is lanthanum.
4. The rare earth-based biomimetic mineralized super-hydrophilic material according to claim 1, characterized in that: The substrate is a polymer substrate.
5. A method for preparing the rare earth-based biomimetic mineralized super-hydrophilic material according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: S1: soaking the polymer substrate with ethanol, taking it out, dipping it in a tannic acid solution, taking it out again, rinsing it, dipping it in a rare earth salt solution, taking it out again, rinsing it, and drying it to obtain a modified polymer; S2: After immersing the modified polymer obtained in step S1 in a rare earth salt solution, taking it out and rinsing it, then immersing it in a phosphate solution, taking it out and rinsing it, repeating the above rare earth salt solution immersion, rinsing, and phosphate solution immersion and rinsing process, and then drying it to obtain a rare earth-based biomimetic mineralized super hydrophilic material.
6. The preparation method according to claim 5, characterized in that In step S1, the polymer substrate includes a separation membrane or a separation net, and the material of the polymer substrate includes one or more of polyvinylidene fluoride, nylon, and polyethersulfone.
7. The preparation method according to claim 5, characterized in that In steps S1 and S2, the rare earth salt is a soluble rare earth salt, and the concentration of the rare earth salt solution is 0.05-0.5 mol / L.
8. The preparation method according to claim 5, characterized in that In steps S1 and S2, the rare earth salt is lanthanum chloride.
9. The preparation method according to claim 5, characterized in that In step S1, the concentration of the tannic acid solution is 1-10 mg / L; and the immersion time is 0.5-2 h.
10. The preparation method according to claim 5, characterized in that In step S2, the phosphate is a soluble phosphate, and the concentration of the phosphate solution is 0.05-0.5 mol / L; the immersion time is 1-5 min, and the number of cycles is 1-10 times.
11. The preparation method according to claim 5, characterized in that In step S2, the phosphate is sodium dihydrogen phosphate or disodium hydrogen phosphate.
12. An application of the rare earth-based biomimetic mineralized super-hydrophilic material according to any one of claims 1 to 4, characterized in that: The rare earth-based biomimetic mineralized super-hydrophilic material is used for oil-water separation.