Multi-in-one intelligent corrosion inhibitor as well as preparation method and application thereof

Abstract

The invention relates to the technical field of marine intelligent corrosion inhibitors, in particular to a multi-in-one intelligent corrosion inhibitor and a preparation method and application thereof. The invention relates to a multi-in-one intelligent corrosion inhibitor, which consists of an intelligent reservoir for storing a corrosion inhibitor and a corrosion inhibitor-sodium gluconate (SG) encapsulated in the intelligent reservoir, and the intelligent reservoir is hydroxyapatite (Cl * at Zn < 2 + > at HAP) which is modified by a chloride ion probe and is doped with Zn < 2 + > to partially replace Ca < 2 + > and has a mesoporous structure. According to the intelligent reservoir, Ca < 2 + > with poor corrosion inhibition capacity is partially replaced by Zn < 2 + > doping, a blocking channel is expanded, the corrosion inhibition gain effect is improved, the intelligent reservoir is combined with the chloride ion probe, and the response capacity to corrosion sites under the maritime work condition is achieved. By combining Zn < 2 + >, phosphate and chloride ion probe technologies and starting from a reservoir, the intelligent corrosion inhibitor can efficiently block corrosive media in a multi-in-one manner, a new direction is opened up for research and application of the efficient intelligent corrosion inhibitor, and the efficient intelligent corrosion inhibitor has potential practical value and a desirable market momentum.

Description

Technical Field

[0001] The present invention relates to the technical field of marine intelligent corrosion inhibitors, and more specifically, to a multi-functional intelligent corrosion inhibitor and its preparation method and application. Background Art

[0002] China's coastline stretches for thousands of miles, with rich marine resources and bright prospects for marine development and construction. A series of marine engineering projects such as offshore wind power, cross-sea bridges, and offshore drilling platforms have great potential. However, the marine environment is ever-changing, posing higher requirements for the steel matrix of marine engineering. Among them, steel corrosion poses the greatest economic and safety threats. As a simple and efficient means of preventing and controlling metal corrosion, corrosion inhibitors are an important anti-corrosion measure for the steel structures of marine engineering.

[0003] The anti-corrosion effect of corrosion inhibitors is obvious, but they are prone to loss and have a limited lifespan in the open and flowing marine environment, severely restricting the use of corrosion inhibitors. To address this limitation, "intelligent corrosion inhibitors" have emerged. The so-called "intelligent corrosion inhibitors" consist of three parts: corrosion inhibitors, intelligent carrier control reservoirs, and stimuli sources. Among them, the construction of the intelligent carrier control reservoir is of utmost importance. The intelligent carrier control reservoir needs to meet the following two points: First, it has a large specific surface area / pore volume to be able to load and store corrosion inhibitors, isolating the direct contact between the corrosion inhibitors and the marine environment; Second, it can intelligently identify and respond to changes in certain conditions during the steel corrosion process, that is, the stimuli source, such as pH, ion concentration, magnetic field, etc. Thus, under the stimulation of the stimuli source, the intelligent carrier control reservoir responds and releases corrosion inhibitors into the corrosion environment, extending the lifespan and use efficiency of the corrosion inhibitors.

[0004] Hydroxyapatite is a natural mineral contained in bones, teeth, shells, etc., and is widely used in the biomedical field due to its good biocompatibility and affinity. As a reservoir for many drugs, hydroxyapatite has good compound loading and storage and transportation capabilities. This meets the prerequisite conditions for an intelligent carrier control reservoir for corrosion inhibitors. To improve performance, zinc can be added to improve the effect of hydroxyapatite; however, applying hydroxyapatite or modified hydroxyapatite alone in metals cannot achieve targeted directional protection of high-chloride salt corrosion areas. It has become crucial to achieve its response to changes in the corrosion environment during the application of hydroxyapatite. Therefore, the construction of the intelligent carrier control reservoir is the primary problem in obtaining intelligent corrosion inhibitors at present. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above limitations existing in the existing marine corrosion inhibitor technology, and to provide a multi-functional intelligent corrosion inhibitor and its preparation method and application.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A multi-functional intelligent corrosion inhibitor, characterized in that it consists of an intelligent reservoir for storing the corrosion inhibitor and the corrosion inhibitor-sodium gluconate (SG) encapsulated therein; the intelligent reservoir is Zn modified by a chloride ion probe 2+ with a partial substitution of Ca by doping 2+ in the mesoporous structure of hydroxyapatite (Cl*@Zn 2+ @HAP).

[0008] The mass content of SG in the intelligent corrosion inhibitor is 5.82 - 5.75%.

[0009] A preparation method of the multi-functional intelligent corrosion inhibitor described above,

[0010] 1) Preparation of the intelligent reservoir with hollow and mesoporous structures: Mix the calcium acetate aqueous solution and the sodium bicarbonate aqueous solution with ethylene glycol respectively. Rapidly add an equal amount of the sodium bicarbonate solution to the obtained calcium acetate solution, and magnetically stir for 3 - 4 h to make calcium carbonate (CaCO 3 ) at the core, then add the phosphorus source, continuously stir for 12 - 15 h, and after stirring, centrifuge and wash with acetic acid solution to obtain hollow and mesoporous hydroxyapatite (HAP);

[0011] 2) Preparation of the intelligent reservoir with hollow and mesoporous structures modified by a chloride ion probe. Under vacuum, use the vacuum impregnation method to mix the above-obtained hollow and mesoporous hydroxyapatite (HAP), zinc acetate and water (as the multi-component HAP reservoir solution), and after mixing, add it to the chloride ion probe solution and carry out a mixing reaction at 50 - 60 °C under stirring conditions, and keep stirring for 24 - 26 h under a magnetic stirrer to make the chloride ion probe interact with the surface of hydroxyapatite to achieve the modification process, and then centrifuge, wash and dry to obtain Zn modified by a chloride ion probe 2+ with a partial substitution of Ca by doping 2+ in hydroxyapatite (Cl*@Zn 2+ @HAP);

[0012] Among them, the chloride ion probe solution is p-methylaminobenzoic acid protonated by titration with 1 mol / L HBr; the multi-component HAP reservoir solution is added with p-methylaminobenzoic acid (in the chloride ion probe solution) according to the [P+-H…O] hydrogen bond molar stoichiometric ratio (10 -3 ~5×10 -3 mol / L);

[0013] 3) Use the vacuum impregnation method to load SG into the intelligent reservoir obtained in step 2) above to obtain the multi-functional intelligent corrosion inhibitor.

[0014] In step 1), the aqueous calcium acetate solution and the aqueous sodium bicarbonate solution are in a ratio of 1:1; the addition amount of ethylene glycol is 5-7 times the volume of the aqueous calcium acetate solution or the aqueous sodium bicarbonate solution; the volume ratio of the aqueous calcium acetate solution to the phosphoric acid solution is 2-2.5:1.

[0015] In step 2), the mass ratio of mesoporous hydroxyapatite (HAP), zinc acetate, p-methylaminobenzoic acid, and water is 1:5-7:3-5:10-13.

[0016] In step 3), each reservoir is added to an aqueous solution of SG, ultrasonically treated for 2-5 minutes, and then placed in a vacuum oven at -0.1 MPa for 30-40 minutes; then the above process is repeated 6-8 times. After centrifugation, washing, and drying, an intelligent corrosion inhibitor is prepared.

[0017] Application of a multi-functional intelligent corrosion inhibitor as described above, the multi-functional intelligent corrosion inhibitor is used as a corrosion inhibitor for protecting metal substrates against corrosive media in the field of ocean engineering.

[0018] In the present invention, the Zn 2+ @HAP reservoir has sufficient space to store the corrosion inhibitor SG, and at the same time, it targets and responds to acidic environments to intelligently control the release of corrosion-inhibiting substances, realizing the intelligence of the reservoir. In addition, Zn 2+ @HAP itself acid-dissociates to release phosphate, Ca 2+ and / or Zn 2+ cooperates with the stored SG, complements each other, and provides a more long-lasting corrosion inhibition enhancement effect. At the same time, the intelligent reservoir is modified by a chloride ion probe, providing the intelligent reservoir with chloride ion response ability under neutral conditions on the basis of pH response. The corrosion inhibitor SG plays a crucial role in the initial stage of corrosion inhibition, avoiding rapid corrosion in the initial stage. As time goes by, phosphate chelates iron ions, calcium ions, or zinc ions to produce insoluble or poorly soluble phosphate deposits on the steel surface, blocking the propagation of corrosive media, making up for the deficiencies of SG due to low storage capacity and poor corrosion inhibition effect, and improving the protection ability against steel corrosion. In addition, the corrosion inhibitor SG can also be embedded into the gaps of the phosphate passivation film to improve the compactness of the passivation film, thereby generating a dense organic-inorganic composite film to block the further erosion of corrosive media, thus prolonging the service life of steel. Phosphate and the corrosion inhibitor SG intervene in the anodic reaction of steel corrosion from the reaction mechanism. Therefore, Zn 2+ with more corrosion inhibition is doped and modified, and Zn 2+, intervening in the cathodic reaction of steel corrosion, starting from multiple stages of steel corrosion to intercept, further improving the steel corrosion protection ability, and using a more sensitive chloride ion probe to respond to the high chloride salt concentration in the severely corroded area, so that the intelligent reservoir has the response ability to adapt to high chloride salt corrosion environments such as the ocean.

[0019] Theoretically, the reservoir Cl*@Zn 2+ @HAP can store corrosion inhibitors, isolate the corrosion environment, quickly release the stored corrosion inhibitors under the stimulation of acid and chloride ions, and self-acidify into phosphates, releasing Ca 2+ or Zn 2+ , and jointly intercept each path of corrosion erosion with the corrosion inhibitors stored and released, curbing the corrosion of steel.

[0020] Specifically, the prepared reservoir can jointly resist the erosion of corrosive media from different channels while intelligently responding to acid, greatly improving the corrosion inhibition protection time and effect.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Environmentally friendly. The intelligent corrosion inhibitor of the present invention, whether it is the reservoir or the carried corrosion inhibitor, exists naturally and will not cause pollution and damage to the marine environment, meeting the requirements of biocompatibility, green and non-toxic.

[0023] 2. Response recognition. The intelligent corrosion inhibitor of the present invention can recognize acid and quickly release corrosion-inhibiting substances, which is beneficial for the intelligent corrosion inhibitor to target and recognize the change in the acidity of the microenvironment in the anodic area of steel corrosion. At the same time, the intelligent release of corrosion-inhibiting substances intervenes in the continuously increasing chloride salt concentration during the corrosion process to play a role, thereby prolonging the life of the corrosion inhibitor and improving the corrosion inhibition efficiency.

[0024] 3. Chloride ion targeted binding. The intelligent corrosion inhibitor of the present invention can recognize the change in chloride ion concentration, which is beneficial for reducing the chloride ion concentration in the corrosion area while quickly releasing the corrosion inhibitor to the high chloride salt area, and the intelligent release of corrosion-inhibiting substances intervenes in the corrosion process to play a role, thereby avoiding waste of the corrosion inhibitor and improving the corrosion inhibition life.

[0025] 4. Corrosion inhibition gain. When the intelligent corrosion inhibitor of the present invention intelligently releases in response to chloride ions, the reservoir itself will also undergo acidolysis to release phosphates, Ca 2+ and / or Zn 2+ and other corrosion-inhibiting substances participate in multiple stages of steel corrosion, and cooperate with the corrosion inhibitor SG stored and released to jointly resist the chloride salt corrosion of steel. This not only improves the corrosion inhibition efficiency and corrosion inhibition time, but also greatly saves the application amount of the corrosion inhibitor SG, realizing the corrosion inhibition gain for high chloride salt environments.

[0026] 5. Intelligent regulation. Based on the above characteristics of the chloride ion probe-modified hydroxyapatite, the intelligent corrosion inhibitor of the present invention releases phosphate, Ca 2+ and / or Zn 2+ , and the content thereof is related to the environmental chloride ion concentration. Through the modification of the chloride ion probe, when the chloride ion concentration continuously increases, the dissociation of hydroxyapatite is continuously regulated, thereby realizing the intelligent regulation of the release amount of the corrosion inhibitor substance.

[0027] 6. Multi-faceted integration. In the intelligent corrosion inhibitor of the present invention, the stored SG is an adsorption-type corrosion inhibitor, which is adsorbed on the steel surface through the complexation between the polar group and Fe. The phosphate released by the acidolysis of the reservoir HAP is a precipitation film-type corrosion inhibitor, which deposits on the steel surface by generating insoluble iron phosphate salt with the iron ions of the steel anode corrosion product, playing the role of isolating the corrosion medium. Both of these mainly start from the anodic reaction of steel corrosion. And after doping and modification with Zn 2+ , the reservoir Zn 2+ @HAP will also release Zn 2+ during acidolysis, which intervenes in the cathodic process of steel corrosion, and intervenes from multiple aspects such as anodic and cathodic reactions, chelation passivation, and coordination adsorption to prevent corrosion from occurring, thereby providing a construction method for an efficient intelligent corrosion inhibitor.

[0028] 7. Synergistic effect. In the intelligent corrosion inhibitor of the present invention, sodium gluconate (SG), hydroxyapatite (HAP), Zn 2+ and the chloride ion probe (Cl*) can jointly cope with various harsh corrosion environments, and have a response effect on corrosion media such as acid and chloride ions. Under the combined action of the four substances, a multi-functional integrated intelligent corrosion inhibitor reservoir system is formed. Brief Description of the Drawings

[0029] Figure 1 shows the synthesis route and application principle of the intelligent corrosion inhibitor provided by the embodiment of the present invention.

[0030] Figure 2 shows the scanning electron microscope morphology diagrams of the intelligent corrosion inhibitor provided by the embodiment of the present invention (HAP) (a), (Cl*@Zn 2+ @HAP) (b).

[0031] Figure 3 shows the chloride ion concentration response change diagram of the intelligent corrosion inhibitor (Cl*@Zn 2+ @HAP) provided by the embodiment of the present invention Detailed Embodiments

[0032] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments. However, the embodiments do not impose any form of limitation on the present invention. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are all conventional reagents, methods, and equipment in the technical field.

[0033] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0034] Based on the correlation between the corrosion degree of the steel anode and the change in the acidity of the anode microenvironment, as well as the correlation between the chloride ion concentration in the corrosion area, the present invention uses hydroxyapatite as a reservoir to intelligently identify the steel anode area and targetedly regulate the release of corrosion inhibitors (SG, Cl*, phosphate, Ca 2+ and / or Zn 2+ ). Through synergistic enhancement, it intervenes in the corrosion process from multiple aspects and inhibits steel corrosion in a multi-faceted manner.

[0035] In ocean engineering, the present invention not only solves the problems that occur during the actual application of corrosion inhibitors, but also overcomes to a certain extent the problems of low reservoir storage in the intelligent corrosion inhibitor system and insufficient efficiency of the corrosion inhibitor itself, providing a promising solution for constructing an efficient intelligent corrosion inhibitor.

[0036] Furthermore, the intelligent corrosion inhibitor utilizes the acidolysis characteristics of HAP to enable it to target and identify the acidic and high-chloride salt environment of the corrosion anode, undergo acidolysis, and thus break the reservoir structure to rapidly release corrosion inhibitors (SG, Cl*, phosphate, Ca 2+ and / or Zn 2 + ). Moreover, according to the pH and chloride ion concentration of the corrosion microenvironment, it will intelligently regulate the release amount of corrosion inhibitors (phosphate, Cl*, Ca 2+ and / or Zn 2+ ), synergistically load the corrosion inhibitor SG, generate a corrosion inhibition enhancement effect, and further overcome the limitations of SG as a corrosion inhibitor, such as large dosage, high cost, and low corrosion inhibition effect, making SG have application value as a corrosion inhibitor, and thus achieving targeted identification, intelligent controlled release, and high-efficiency corrosion inhibition.

[0037] At the same time, after Zn 2+ @HAP is doped and modified with Zn 2+ , the addition of Zn 2+ expands the corrosion interception channels. Starting from the corrosion cathode reaction, by combining with the cathode corrosion product OH - to form insoluble Zn(OH) 2 deposited on the cathode reaction site to block the progress of the corrosion reaction, and superimposing phosphate and SG, thereby providing a new and efficient corrosion interception strategy.

[0038] In Cl*@Zn 2+After the @HAP is modified by the chloride ion probe Cl*, the range of corrosion environment conditions is expanded. In neutral and alkaline environments with high chloride salts, through the combination of the chloride ion probe and environmental chloride ions, corrosion inhibitors (SG, Cl*, phosphate, Ca 2+ and / or Zn 2+ ) in the intelligent reservoir are released, providing an application prospect in the marine environment and achieving a multi-component synergistic corrosion inhibition effect.

[0039] Example 1 Cl*@Zn 2+ Preparation of @HAP-SG

[0040] Step 1 Preparation of HAP with hollow and mesoporous structures

[0041] First, prepare a 0.3M aqueous solution of calcium acetate and a 0.5M aqueous solution of sodium bicarbonate, and add 5 times the volume of ethylene glycol to each, and stir magnetically until evenly mixed. Rapidly add an equal volume of sodium bicarbonate solution to the calcium acetate solution and stir magnetically for 3 h to obtain calcium carbonate (CaCO 3 ) cores. Then add 1% v / v of H 3 PO 4 solution as a phosphorus source and continuously stir for 12 h. And obtain a hollow structure by centrifugal washing with 0.2% v / v acetic acid solution. Finally, obtain HAP through centrifugation, washing, and drying.

[0042] Step 2 Preparation of Cl*@Zn 2+ @HAP

[0043] For the HAP prepared in Step 1, the HAP reservoir is modified with a chloride ion probe. The specific process is as follows: Preparation of an intelligent reservoir with hollow and mesoporous structures modified by a chloride ion probe. Under vacuum conditions, use the vacuum impregnation method to mix the obtained hollow and mesoporous hydroxyapatite (HAP), zinc acetate, and water (as a multi-component HAP reservoir solution, where the mass ratio of hydroxyapatite (HAP), zinc acetate, and water is 1:5:10), and after mixing, add it to the chloride ion probe solution and carry out a mixing reaction at 50 °C under stirring conditions, and keep stirring for 24 h under a magnetic stirrer to enable the chloride ion probe to interact with the surface of hydroxyapatite to achieve the modification process, and then centrifuge, wash, and dry to obtain hydroxyapatite in which the doped part replaces Ca 2+ (Cl*@Zn 2+ @HAP); 2+ @HAP);

[0044] Among them, the chloride ion probe solution is p-methylaminobenzoic acid protonated by titration with 1 mol / L HBr; the multi-component HAP reservoir solution is added with p-methylaminobenzoic acid (in the chloride ion probe solution) according to the [P+-H…O] hydrogen bond molar stoichiometric ratio (3×10-3 mol / L);

[0045] Step 3 Loading of Corrosion Inhibitor SG

[0046] Load SG onto Cl*@Zn 2+ @HAP reservoir by vacuum impregnation method. Add the Cl*@Zn 2+ @HAP reservoir into an aqueous solution of SG (concentration: 50 mg / mL), sonicate for 2 minutes, and then place it in a vacuum oven at -0.1 MPa for 30 minutes. Repeat this process six times. Then, obtain the intelligent corrosion inhibitor Cl*@Zn 2+ @HAP-SG through centrifugation, washing, and drying (see Figure 2 ).

[0047] As can be seen from Figure 2 SG in Cl*@Zn 2+ @HAP-SG is successfully loaded onto hydroxyapatite.

[0048] Example 2 SG Content in Cl*@Zn 2+ @HAP-SG

[0049] Perform thermogravimetric analysis on the Cl*@Zn 2+ @HAP-SG prepared in Example 1 and SG. Determine the inhibitor loading rate by thermogravimetry. The analysis method refers to the reference: T. Miri, D. Seifzadeh and Z. Rajabalizadeh. Smart epoxycoating containing inhibitor-loaded cellulose nanocrystals for corrosionprotection of steel[J]. Surf. Coat. Tech., 2024, 477: 130241.

[0050] The analysis results show that the loaded mass content of SG in Cl*@Zn 2+ @HAP-SG is 5.75%. Example 3 Release Behavior and Chloride Ion Responsiveness of Cl*@Zn 2 + @HAP-SG

[0051] Perform release behavior tests on the Cl*@Zn 2+ @HAP-SG prepared in Example 1. Use high-performance liquid chromatography-ultraviolet absorption detector to determine Cl*@Zn 2+ @HAP-SG in a neutral solution without Cl - and with the addition of 0.8 M Cl -The release behavior of SG in the middle, and the analysis method: References: Yu Xingjia, Chen Jing. Research on the determination of sodium gluconate and sodium acetate content in balanced salt irrigation solution by high performance liquid chromatography [J]. Technology and Market, 2019, 26(9): 3. At the same time, compared with the HAP-SG inhibitor, Cl*@Zn 2+ The change of chloride ion response release performance of the @HAP-SG composite reservoir.

[0052] The HAP-SG inhibitor prepares HAP according to the description in Example 1 above, and then prepares the inhibitor according to the description in its step 3.

[0053] The analysis results show that Cl*@Zn 2+ The release amount of SG after 2 h of @HAP-SG in a neutral solution without chlorine is 36%, while the release amount of SG after 2 h in a chlorine-containing solution (0.8 M) is 89%, far exceeding the release amount in a chlorine-free environment. When the HAP-SG composite reservoir is used alone, the release amount in both chlorine-containing and chlorine-free solutions is less than 35%. This shows that Cl*@Zn 2+ The @HAP-SG reservoir has the ability to recognize the chloride ion environment. Cl*@Zn 2+ The ability of the Cl*@Zn Figure 3 @HAP-SG reservoir to recognize the chloride ion environment is characterized by its selective adsorption response release chart of chloride ions through an electrochemical quartz crystal microbalance, as

[0054] Example 4 The chloride ion responsiveness of Cl*@Zn 2+ @HAP-SG

[0055] Conditions: In the following studies, Q235 carbon steel was used as the working electrode to simulate offshore steel facilities, and the exposed area was 1 cm 2 . The NaCl solution was used to simulate different concentrations of chloride salt environments to accelerate the release of the inhibitor from the reservoir. The intelligent inhibitor Cl*@Zn 2 + @HAP-SG and the addition amount of HAP-SG were 1 g / L. The following electrochemical tests were carried out at room temperature. The electrochemical test solution was 100 mL.

[0056] There are two cases in total: First, add an equal mass content of the HAP-SG reservoir alone, that is, 0.1 g; Second, add 0.1 g of Cl*@Zn 2+ @HAP-SG.

[0057] The corrosion inhibition performance was tested by electrochemical impedance spectroscopy. References: Z. Li, J. Cao, T. Mao, et al. Synthesis of Bimannich Base with Thiazole and Its Corrosion Inhibition Effect on H 2 S and CO 2 at High Temperature[J]. BMC Chem., 2021, 15(1).

[0058] There are four types, namely chloride ion concentrations of 0.2, 0.4 M, 0.6 M, and 0.8 M respectively.

[0059] The corrosion inhibition performance was tested by electrochemical impedance spectroscopy. The method is as follows, and the test results are shown in Table 1.

[0060] Corrosion inhibition efficiency in the four environments with different chloride ion concentrations described in Table 1

[0061] Add intelligent reservoir Chloride ion concentration (M) Corrosion inhibition efficiency (%) <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 0.2 62.27％ <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 0.4 65.85％ <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 0.6 86.54％ <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 0.8 92.71％ HAP-SG 0.2 34.51％ HAP-SG 0.8 35.24％

[0062] It was found that the higher the chloride ion concentration, the better the protective effect of the intelligent corrosion inhibitor Cl*@Zn 2+ @HAP-SG on steel. Therefore, the improvement of this anti-corrosion performance is related to the dissociation of HAP in the reservoir and the degradation degree of chloride ion concentration. The higher the content of phosphate released, the better the chloride ion probe binds to chloride ions in the environment, and the better the corrosion inhibition synergistic effect. This characteristic can make intelligent regulation according to the different degrees of chloride ion concentration increase corresponding to different degrees of steel corrosion. The more severe the corrosion, the higher the environmental chloride ion concentration, and the more phosphate released by Cl*@Zn 2+ @HAP-SG, providing a better synergistic protection strategy.

[0063] Example 5 Cl*@Zn 2+ @HAP-SG's multi-faceted high corrosion inhibition

[0064] The implementation conditions in Example 4 were adopted. The only difference was the different types of intelligent corrosion inhibitors added, namely HAP-SG and Cl*@Zn 2+ @HAP-SG.

[0065] The corrosion inhibition performance was tested by electrochemical impedance spectroscopy. The method was as in Example 4, and the test results are shown in Table 2.

[0066] Table 2 Corrosion inhibition efficiency of HAP-SG and Zn 2+ @HAP-SG

[0067] Intelligent corrosion inhibitor Immersion time (h) Corrosion inhibition efficiency (%) HAP-SG 6 64.5 HAP-SG 12 68.3 HAP-SG 24 71.7 HAP-SG 48 83.7 <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 6 96.3 <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 12 97.4 <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 24 98.6 <![CDATA[Cl*@Zn 2+ @HAP-SG]]> 48 98.8

[0068] It was found that Cl*@Zn 2+ After doping and modification with @HAP-SG, the protection effect of the intelligent corrosion inhibitor system was greatly improved, and the corrosion inhibition efficiency within 48 h was above 97%, indicating the barrier effect of its corrosion inhibition protective layer. In addition, Cl*@Zn 2+ @HAP-SG had a much higher corrosion inhibition effect during the whole immersion period than HAP-SG. It can be seen that Cl*@Zn 2+ @HAP-SG gave full play to the protective performance per unit dose while responding to the chloride ion concentration in the corrosive environment, and greatly improved the corrosion inhibition performance on the premise of maintaining the dosage. The mechanism involved the participation of Zn 2+ in combination with phosphate and SG in multiple stages of corrosion, and they jointly and synergistically constructed a corrosion inhibition layer to block the corrosive medium. Cl*@Zn 2+ @HAP-SG's high corrosion inhibition property indicates that metal ions with corrosion inhibition synergy, such as Zn 2+ , can be doped into the reservoir HAP through a simple method, thereby greatly improving the ability of the intelligent corrosion inhibitor system to block the corrosion of steel at the same dose. At the same time, a chloride ion probe was added for modification. The corrosion inhibition efficiency above 97% enabled Zn 2+ @HAP-SG to have the prerequisite background for marine engineering applications. Cl*@Zn 2+ @HAP-SG's continuously increasing high corrosion inhibition performance during the long-term process indicates that the Cl*@Zn 2+ @HAP-SG can be further modified by applying a chloride ion probe, thereby greatly improving the ability of the intelligent corrosion inhibitor system to block chloride ions in the corrosion of steel at the same dose. It improved the application prospect of the intelligent corrosion inhibition reservoir in a high-chloride corrosion environment.

[0069] The multi-functional intelligent corrosion inhibitor of the present invention uses environmentally friendly hydroxyapatite as the intelligent reservoir of the corrosion inhibitor, targets and identifies the environmental pH and chloride ion concentration to intelligently control the release of corrosion inhibitors, synergistically enhances the corrosion inhibition performance, and realizes the multi-function integration of environmental friendliness, target recognition, intelligent control release, and corrosion inhibition enhancement of marine corrosion inhibition materials. And the HAP reservoir can be modified by simple Zn 2+ doping, and then the modified Zn 2+ @HAP-SG is modified with a chloride ion probe. After modification, it not only blocks the corrosion reaction from multiple aspects such as the anodic and cathodic reactions of corrosion, chelation passivation, and coordination adsorption, but also provides excellent chloride ion corrosion blocking performance for its application in the field of ocean engineering.

Claims

1. A multi-in-one intelligent corrosion inhibitor, characterized in that: It consists of a smart reservoir for storing corrosion inhibitors and a corrosion inhibitor encapsulated therein, sodium gluconate (SG); the smart reservoir is Zn modified by a chloride ion probe. 2+ Doping partially replaces Ca 2+ Mesoporous structure of hydroxyapatite (Cl*@Zn 2+ @HAP).

2. The multi-in-one intelligent corrosion inhibitor according to claim 1, characterized in that: The mass content of SG in the intelligent corrosion inhibitor is 5.82-5.75%.

3. A method for preparing the multi-in-one intelligent corrosion inhibitor according to claim 1, characterized in that: 1) Preparation of a smart reservoir with a hollow and mesoporous structure: A calcium acetate aqueous solution and a sodium bicarbonate aqueous solution are mixed with ethylene glycol respectively, and an equal amount of sodium bicarbonate solution is quickly added dropwise to the obtained calcium acetate solution, and magnetic stirring is performed for 3-4 hours to make calcium carbonate (CaCO3) in the core, and then a phosphorus source is added, and stirring is continued for 12-15 hours. After stirring, the hollow and mesoporous hydroxyapatite (HAP) is obtained by centrifugation and washing with an acetic acid solution; 2) Preparation of a hollow and mesoporous smart reservoir modified by a chloride ion probe, in a vacuum state, the above-mentioned hollow and mesoporous hydroxyapatite (HAP), zinc acetate and water are mixed by vacuum impregnation method, and then added to a chloride ion probe solution for mixing reaction at 50-60°C under stirring conditions, and stirred for 24-26 hours under a magnetic stirrer to allow the chloride ion probe to interact with the hydroxyapatite surface to achieve the modification process, and then centrifuged, washed and dried to obtain the chloride ion probe modified Zn 2+ Doping partially replaces Ca 2+ Hydroxyapatite (Cl*@Zn 2+ @HAP); The chloride ion probe solution is p-aminobenzoic acid protonated with 1 mol / L HBr; the polyvalent HAP reservoir solution is added with p-aminobenzoic acid (in the chloride ion probe solution) according to the [P+-H…O] hydrogen bond molar ratio (10 -3 ~5×10 -3 mol / L); 3) Using a vacuum impregnation method, SG is loaded into the smart reservoir obtained in the above step 2) to obtain a multi-in-one smart corrosion inhibitor.

4. The method for preparing the multi-in-one intelligent corrosion inhibitor according to claim 3, characterized in that: In the step 1), the calcium acetate aqueous solution and the sodium bicarbonate aqueous solution are in a ratio of 1:1; the amount of ethylene glycol added is 5-7 times the volume of the calcium acetate aqueous solution or the sodium bicarbonate aqueous solution respectively; and the volume ratio of the calcium acetate aqueous solution to the phosphoric acid solution is 2-2.5:

1.

5. The method for preparing the intelligent reservoir agent modified by chloride ion probe and having hollow and mesoporous structure according to claim 3, characterized in that: In the step 2), the mass ratio of the mesoporous hydroxyapatite (HAP), zinc acetate, p-aminobenzoic acid and water is 1:5-7:3-5:10-13.

6. The method for preparing the multi-in-one intelligent corrosion inhibitor according to claim 3, characterized in that: In the step 3), each reservoir is added to the aqueous solution of SG, ultrasonically treated for 2-5 minutes, and then placed in a vacuum oven at -0.1MPa for 30-40 minutes; then the above process is repeated 6-8 times; and then the intelligent corrosion inhibitor is obtained by centrifugation, washing and drying.

7. An application of the multi-in-one intelligent corrosion inhibitor according to claim 1, characterized in that: The multi-in-one intelligent corrosion inhibitor is used in the field of marine engineering as a corrosion inhibitor for protecting metal substrates from corrosive media.

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