A graphene oxide@bio-based porous silicon core-shell structured slow-release container, its preparation method and application

Abstract

This invention discloses a graphene oxide@bio-based porous silicon core-shell structured slow-release container, its preparation method, and its application. The container comprises a core-shell structure composed of porous silicon and graphene oxide, and a corrosion inhibitor loaded onto the shell structure. The core-shell structure includes a porous silicon core and a graphene oxide shell covering the outer surface of the porous silicon core. A GO ethanol dispersion was prepared using Hummer's method and solvent displacement method. Simultaneously, bio-based porous silicon obtained from straw combustion and the corrosion inhibitor benzotriazole were mixed and dispersed in an ethanol solution. The GO ethanol dispersion was then mixed with bio-based porous silicon and a BTA ethanol dispersion, and the BTA-loaded GO@bio-based porous silicon core-shell structured nanomaterial was prepared by spray drying. This invention synthesizes a BTA-loaded GO@bio-based porous silicon core-shell structured nanomaterial using a simple spray drying method, which can be used as a slow-release container to achieve efficient encapsulation and controlled slow release of BTA.

Description

Technical Field

[0001] This invention belongs to the field of coatings and fillers, and relates to a slow-release container with graphene oxide (GO)@bio-based porous silicon core-shell structure, its preparation method and application. Background Technology

[0002] Corrosion of metallic materials causes serious safety accidents and economic losses every year, and has long been considered a serious global problem, urgently requiring the development of efficient methods to control or mitigate metal corrosion. Currently, various anti-corrosion methods have been developed, among which the synthesis and use of corrosion inhibitors is one of the more popular and economical methods. Commonly used corrosion inhibitors include 8-hydroxyquinoline, 2-mercaptobenzothiazole, and benzotriazole (BTA). These organic corrosion inhibitors can be adsorbed onto the surface of metals and alloys through heteroatom π electrons, forming a protective surface barrier, thereby protecting the metal from corrosion degradation. Their advantage is that a small amount can form a significant protective effect. The disadvantage is that a continuous supply is required to achieve long-term corrosion protection. Therefore, in the field of coatings, to achieve long-term corrosion inhibition, researchers have previously used micro-nano slow-release containers to load corrosion inhibitors to achieve small-volume, long-term corrosion protection.

[0003] Micro-nano slow-release containers should meet two criteria: (1) they should have sufficient capacity to encapsulate corrosion inhibitors; and (2) they should have the ability to control the release of corrosion inhibitors. Currently commonly used nanocontainers include carbon nanotubes (CNs), layered double hydroxides (LDHs), mesoporous silica (SiO2), kaolinite nanotubes (HNTs), and metal-organic frameworks (MOFs).

[0004] Current research on porous sustained-release containers mainly focuses on controlling the pore size of porous materials or achieving controlled sustained release through methods such as coating the surface of porous materials. For example, Liu... [1] Hao et al. prepared a core-shell structure of CeO2 / BTA / (polyethyleneimine PEI / polystyrene sulfonate PSS), and used the PEI / PSS shell to encapsulate the CeO2 nanocapsule to control the release of BTA, thus achieving controllable release. [2] Researchers prepared mesoporous polyaniline (mPANI) hollow nanospheres using core / shell structured silica nanospheres as substrates, and controlled the release and loading of corrosion inhibitors by adjusting pore diameter, specific surface area, and total pore volume.

[0005] Graphene oxide (GO) is a novel lightweight two-dimensional nanomaterial with high barrier properties, excellent mechanical properties, high stability, and flexibility. However, existing research mainly focuses on the simple composite of two-dimensional flexible GO with porous fillers to integrate barrier and slow-release functions. There are few reports on using GO as a shell material to adjust the loading rate and slow-release efficiency of porous fillers, because solution mixing methods make it difficult to achieve efficient encapsulation and large-scale preparation of GO for porous materials, thus hindering practical applications in coatings. Relying solely on micro-nano slow-release containers is insufficient to effectively control the release behavior of corrosion inhibitors, leading to rapid consumption of the inhibitor within a short time. Furthermore, the rapid release of excessive inhibitor molecules within the coating can damage the internal structure, resulting in a decline in the coating's intrinsic properties. Therefore, how to utilize the structural characteristics of GO to assist in controlling the slow-release rate of corrosion inhibitors remains a technical challenge.

[0006] References

[0007] [1]

[0008] [2] Y.Hao, L.Song, YJPiOCZhang, A facile method to prepare mesoporous polyaniline hollow nanosphere and its application in self-healingcoating, 168(2022)106912. Summary of the Invention

[0009] Purpose of the invention: The technical problem to be solved by the present invention is that the corrosion inhibitor loading capacity and the release rate are uncontrollable in the coating slow release application of porous nano-release containers. The invention proposes a slow release container with graphene oxide (GO)@bio-based porous silicon core-shell structure and its preparation method to alleviate the above problems.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A graphene oxide@bio-based porous silicon core-shell structure slow-release container includes a core-shell structure composed of porous silicon and graphene oxide, and a corrosion inhibitor loaded on the shell structure.

[0012] The core-shell structure includes a porous silicon core and a graphene oxide shell covering the outer surface of the porous silicon core.

[0013] Furthermore, the present invention improves the preparation method of the above-mentioned graphene oxide@bio-based porous silicon core-shell structure slow-release container, comprising the following steps:

[0014] (1) Graphene oxide (GO) aqueous solution was prepared by Hummer's method, and then graphene oxide (GO) was dispersed in anhydrous ethanol by solvent replacement to obtain graphene oxide (GO) ethanol solution.

[0015] (2) Disperse porous silicon and corrosion inhibitor together in ethanol to obtain mixture A;

[0016] (3) The graphene oxide (GO) ethanol solution obtained in step (1) is thoroughly mixed with the mixture A obtained in step (2) to obtain mixture B;

[0017] (4) The mixture B obtained in step (3) is dried by spray drying.

[0018] Specifically, in step (1), the concentration of the graphene oxide (GO) aqueous solution is 5-13 g / L, and the sheet size of the graphene oxide (GO) is 0.1-10 μm.

[0019] Specifically, in step (1), the concentration of the obtained graphene oxide (GO) ethanol solution is 1-20 g / L.

[0020] Specifically, in step (2), the porous silicon is obtained by sintering, reducing and acid washing using straw or rice husks as raw materials, and the porous silicon particle size is 20-100μm.

[0021] Porous silicon possesses a three-dimensional porous structure, giving it a strong capacity to load corrosion inhibitors, making it an advantageous choice for slow-release containers. Furthermore, porous silicon is a bio-based material obtained through the processing of recycled straw, rice husks, and other materials, making it environmentally friendly.

[0022] Specifically, in step (2), the corrosion inhibitor is selected from any one of benzotriazole (BTA), polyaniline (PANI), and methylbenzotriazole (TTA). Benzotriazole (BTA) is preferred.

[0023] Specifically, in step (2), the porous silicon and the corrosion inhibitor are dispersed in ethanol at a mass ratio of 1:1 to 1:10, and ultrasonically combined with mechanical stirring for 30 to 60 minutes to obtain mixture A.

[0024] Specifically, in step (3), the graphene oxide ethanol solution and mixture A are mixed at a mass ratio of graphene oxide to porous silicon of 5 to 10:1, and ultrasonically combined with mechanical stirring for 30 to 60 minutes to obtain mixture B.

[0025] Specifically, in step (3), ethanol is added to make the concentration of graphene oxide in mixture B 1 g / L to 10 g / L; the inlet temperature of the spray dryer is 70 to 90°C, and the feed rate is 1 to 10 mL / min. Preferably, the inlet temperature is 70°C and the feed rate is 3 mL / min.

[0026] Furthermore, the present invention also claims the use of the above-described graphene oxide@bio-based porous silicon core-shell structure slow-release container in the preparation of anti-corrosion coatings for metallic materials.

[0027] Beneficial effects:

[0028] This invention synthesizes a GO@bio-based porous silicon core-shell structure slow-release container loaded with corrosion inhibitor via a simple spray drying method. The process is simple and suitable for industrial-scale production. Secondly, this invention selects bio-based porous silicon as the core material, which has a porous structure and a large specific surface area. Porous silicon obtained by processing straw as the raw material is a bio-based material, which is green and environmentally friendly, beneficial to environmental protection and reducing industrial production costs. Finally, this invention coats the porous silicon surface with GO, which further enhances the loading capacity of the porous silicon and achieves a slow release effect of the corrosion inhibitor. Applying this slow-release container to coatings can further improve the anti-corrosion performance and long-term corrosion resistance of the coating, making it of great application value in the field of marine anti-corrosion coatings. Attached Figure Description

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0030] Figure 1 This is a schematic diagram of the GO@ bio-based porous silicon core-shell structure of the slow-release container.

[0031] Figure 2 This is a scanning electron microscope image of the BTA-loaded GO@bio-based porous silicon core-shell structure sustained-release container prepared in Example 1.

[0032] Figure 3 This is the energy spectrum of the BTA-loaded GO@bio-based porous silicon core-shell structure sustained-release container prepared in Example 1.

[0033] Figure 4 This is a scanning electron microscope image of the bio-based porous silica slow-release container loaded with BTA prepared in Comparative Example 1.

[0034] Figure 5This is the energy spectrum of the bio-based porous silica slow-release container loaded with BTA prepared in Comparative Example 1.

[0035] Figure 6 This is a standard curve showing the relationship between the concentration of corrosion inhibitor BTA and ultraviolet absorbance.

[0036] Figure 7 The graph shows the sustained-release performance of the BTA-loaded sustained-release containers prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0037] The present invention can be better understood from the following embodiments.

[0038] In the following examples, the bio-based porous silica raw material was obtained by sintering, reducing, and acid washing rice husks, with a size of 20-100 μm. The preparation method is based on the applicant's previous patent and paper (CN201410242323.1, https: / / doi.org / 10.1016 / j.ensm.2020.10.002). The concentration of the GO aqueous solution used for Hummer's method exfoliation was 5-13 g / L, wherein the GO nanosheets had a size of 0.1-10 μm.

[0039] Example 1

[0040] (1) GO aqueous solution (concentration of 8 g / L) was obtained by Hummer's method. Then, GO was dispersed in anhydrous ethanol by solvent replacement, and ultrasonication combined with mechanical stirring at 800 r / min for 30 min was used to obtain GO ethanol solution (concentration of 1 g / L).

[0041] (2) Porous silica and corrosion inhibitor benzotriazole (BTA) were dispersed in ethanol at a mass ratio of 1:1, and the mixture was ultrasonicated and mechanically stirred at 600 r / min for 30 min to obtain mixture A;

[0042] (3) Add the GO ethanol solution to mixture A, with the mass ratio of GO, porous silica, and benzotriazole being 10:1:1. Mix the mixture by sonication combined with mechanical stirring at 600 r / min for 30 min to obtain mixture B. Add a certain amount of ethanol to control the concentration of GO in mixture C to be 10 g / L;

[0043] (4) The mixture C was spray-dried to prepare a GO@bio-based porous silica core-shell structure slow-release container loaded with corrosion inhibitor BTA. The inlet temperature of the spray dryer was 70℃, and the feed rate was 3ml / min.

[0044] Example 2

[0045] (1) GO aqueous solution (concentration of 8 g / L) was obtained by Hummer's method. Then, GO was dispersed in anhydrous ethanol by solvent replacement, and ultrasonication combined with mechanical stirring at 800 r / min for 30 min was used to obtain GO ethanol solution (concentration of 1 g / L).

[0046] (2) Porous silica and corrosion inhibitor benzotriazole (BTA) were dispersed in ethanol at a mass ratio of 1:5, and the mixture was ultrasonicated and mechanically stirred at 600 r / min for 30 min to obtain mixture A;

[0047] (3) Add the GO ethanol solution to mixture A, with the mass ratio of GO, porous silica and benzotriazole being 10:1:5. Mix the mixture by sonication combined with mechanical stirring at 600 r / min for 30 min to obtain mixture B. Add a certain amount of ethanol to control the concentration of GO in mixture C to 6 g / L.

[0048] (4) The mixture C was spray-dried to prepare a GO@bio-based porous silica core-shell structure slow-release container loaded with corrosion inhibitor BTA. The inlet temperature of the spray dryer was 70℃, and the feed rate was 3ml / min.

[0049] Example 3

[0050] (1) GO aqueous solution (concentration of 8 g / L) was obtained by Hummer's method. Then, GO was dispersed in anhydrous ethanol by solvent replacement, and ultrasonication combined with mechanical stirring at 800 r / min for 30 min was used to obtain GO ethanol solution (concentration of 1 g / L).

[0051] (2) Porous silica and corrosion inhibitor benzotriazole (BTA) were dispersed in ethanol at a mass ratio of 1:10, and the mixture was ultrasonicated and mechanically stirred at 600 r / min for 30 min to obtain mixture A;

[0052] (3) Add the GO ethanol solution to mixture A. The mass ratio of GO, porous silica and benzotriazole is 5:1:10. Mix the mixture by sonication combined with mechanical stirring at 600 r / min for 30 min to obtain mixture B. Add a certain amount of ethanol to control the concentration of GO in mixture C to 2 g / L.

[0053] (4) The mixture C was spray-dried to prepare a GO@bio-based porous silica core-shell structure slow-release container loaded with corrosion inhibitor BTA. The inlet temperature of the spray dryer was 70℃, and the feed rate was 3ml / min.

[0054] Comparative Example 1

[0055] (1) Porous silica and corrosion inhibitor benzotriazole (BTA) were dispersed in ethanol at a mass ratio of 1:1, and the mixture was ultrasonicated and mechanically stirred at 600 r / min for 60 min to obtain mixture A;

[0056] (2) The mixture A was dried using a spray dryer to prepare a bio-based porous silica slow-release container loaded with corrosion inhibitor BTA. The inlet temperature of the spray dryer was 70℃ and the feed rate was 3ml / min.

[0057] The sustained-release container samples obtained in Examples 1-3 and Comparative Example 1 were subjected to scanning electron microscopy, X-ray energy dispersive spectroscopy, and sustained-release performance testing. The specific testing methods are as follows:

[0058] Sustained-release performance test: A 10 mg / mL BTA aqueous solution was prepared, and the absorption spectrum was measured using a UV-Vis spectrophotometer in the range of 190 nm to 340 nm. 265 nm, where BTA exhibits absorption, was selected as the quantitative measurement point. BTA aqueous solutions with concentrations of 0, 1, 2, 4, 8, 15, 20, 30, 40, 50, and 60 μg / mL were prepared, and their absorbance at 265 nm was measured using a UV-Vis spectrophotometer. A concentration-absorbance standard curve was plotted. Simulation was performed using Origin software, yielding the equation: Abs = 0.047 * Concen + 0.008.

[0059] Take 0.05 g of BTA / GO / porous silica powder and BTA / porous silica powder respectively, disperse them in 100 mL of deionized water and stir mechanically at a stirring speed of 200 rpm. Take 1 mL of solution at 0, 1, 3, 5, 7, 10, 12, 15, 20, 25, 30, 50, 60, 90, 120 and 150 min respectively, filter them with a 0.22 μm aqueous filter, dilute them 10 times, measure the absorbance with a spectrophotometer, and calculate the concentration of BTA in the solution with the help of a standard curve.

[0060] Figure 1 This is a schematic diagram of the slow-release container structure of the GO@ bio-based porous silicon core-shell structure of the present invention, including a core-shell structure composed of porous silicon and graphene oxide, and a corrosion inhibitor loaded on the shell structure; wherein, the core-shell structure includes a porous silicon core and a graphene oxide shell covering the outer surface of the porous silicon core.

[0061] Figure 2 This is a scanning electron microscope image of the BTA-loaded GO@bio-based porous silicon core-shell structured slow-release container prepared in Example 1. The slow-release container is spherical, with GO coating the surface of the porous silicon to form a core-shell structure.

[0062] Figure 3This is the energy dispersive spectroscopy (EDS) spectrum of the BTA-loaded GO@bio-based porous silicon core-shell structure sustained-release container prepared in Example 1. Elemental analysis of C, O, Si, and N showed that C and O were uniformly dispersed on the surface of the structure in a spherical shape, indicating that GO was completely and uniformly coated on the surface, and the BTA-loaded porous silicon was encapsulated inside, resulting in lower Si and N content. This further confirms the successful preparation of the GO@bio-based porous silicon core-shell structure sustained-release container.

[0063] Figure 4 This is a scanning electron microscope (SEM) image of the BTA-loaded bio-based porous silicon slow-release container prepared in Comparative Example 1. The image shows a porous silicon structure with a size of approximately 10–20 μm.

[0064] Figure 5 This is the energy dispersive spectroscopy (EDS) spectrum of the BTA-loaded bio-based porous silica slow-release vessel prepared in Comparative Example 1. No GO was added, so the carbon content is very low. Without GO encapsulation, the porous silica has poor loading capacity, low BTA content, and scarce nitrogen.

[0065] Figure 6 This is a standard curve showing the relationship between the concentration of corrosion inhibitor BTA and ultraviolet absorbance.

[0066] Figure 7 The figures show the sustained-release performance of the BTA-loaded slow-release containers prepared in Example 1 and Comparative Example 3. As can be seen from the figures, the BTA content loaded in the GO@bio-based porous silicon core-shell structure slow-release container is significantly higher than that loaded in porous silicon, increasing by approximately tenfold. Furthermore, the GO encapsulation further slows down the release rate of the corrosion inhibitor BTA, increases the sustained-release time, and improves the sustained-release performance of porous silicon as a slow-release container.

[0067] This invention provides a graphene oxide@bio-based porous silicon core-shell structured slow-release container, its preparation method, and its application. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A graphene oxide@bio-based porous silicon core-shell structure slow-release container, characterized in that, It includes a core-shell structure composed of porous silicon and graphene oxide, and a corrosion inhibitor loaded on the core-shell structure; The core-shell structure includes a porous silicon core and a graphene oxide shell covering the outer surface of the porous silicon core. The graphene oxide@bio-based porous silicon core-shell structured slow-release container was prepared through the following steps: (1) Graphene oxide aqueous solution was prepared by Hummer's method, and then graphene oxide was dispersed in anhydrous ethanol by solvent replacement to obtain graphene oxide ethanol solution. (2) Disperse porous silicon and corrosion inhibitor together in ethanol to obtain mixture A; (3) The graphene oxide ethanol solution obtained in step (1) is thoroughly mixed with the mixture A obtained in step (2) to obtain mixture B; (4) The mixture B obtained in step (3) is dried by spray drying to obtain the final product; In step (1), the sheet size of graphene oxide is 0.1~10μm; In step (2), the porous silicon is obtained by sintering, reducing and acid washing using straw or rice husks as raw materials, and the porous silicon particle size is 20~100μm; In step (3), ethanol is added to make the concentration of graphene oxide in mixture B 1 g / L~10 g / L.

2. The graphene oxide@bio-based porous silicon core-shell structure slow-release container according to claim 1, characterized in that, In step (1), the concentration of the graphene oxide aqueous solution is 5~13 g / L.

3. The graphene oxide@bio-based porous silicon core-shell structure slow-release container according to claim 1, characterized in that, In step (1), the concentration of the obtained graphene oxide ethanol solution is 1~20 g / L.

4. The graphene oxide@bio-based porous silicon core-shell structure slow-release container according to claim 1, characterized in that, In step (2), the corrosion inhibitor is selected from any one of benzotriazole (BTA), polyaniline (PANI), and methylbenzotriazole (TTA).

5. The graphene oxide@bio-based porous silicon core-shell structure slow-release container according to claim 1, characterized in that, In step (2), the porous silicon and corrosion inhibitor are dispersed in ethanol at a mass ratio of 1:1 to 1:10, and ultrasonically combined with mechanical stirring for 30 to 60 minutes to obtain mixture A.

6. The graphene oxide@bio-based porous silicon core-shell structure slow-release container according to claim 1, characterized in that, In step (3), the graphene oxide ethanol solution and mixture A are mixed at a mass ratio of graphene oxide to porous silicon of 5~10:1, and ultrasonically combined with mechanical stirring for 30~60 min to obtain mixture B.

7. The graphene oxide@bio-based porous silicon core-shell structure slow-release container according to claim 1, characterized in that, In step (3), the inlet temperature of the spray dryer is 70~90℃ and the feed rate is 1~10mL / min.

8. The application of the graphene oxide@bio-based porous silicon core-shell structure slow-release container according to claim 1 in the preparation of anti-corrosion coatings for metallic materials.

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