Bio-based metal corrosion inhibitor and preparation method thereof

Abstract

The invention discloses a bio-based metal corrosion inhibitor, which is characterized in that the corrosion inhibitor is formed by mixing a pruned tea tree branch extract and a macleaya cordata pod extract according to a volume ratio of 1: 1-1: 6. Different from the bio-based metal corrosion inhibitor prepared by compounding plant extracts and chemical substances, the bio-based metal corrosion inhibitor prepared by compounding the pruned tea tree branch extract and the macleaya cordata pod extract has the advantages that the two plant extracts are compounded, no chemical product is contained, and the bio-based metal corrosion inhibitor is environmentally friendly and easy to degrade.

Description

Technical Field

[0001] The invention belongs to the technical field of corrosion inhibitors, and specifically relates to a bio-based metal corrosion inhibitor and a preparation method and application thereof. Background Art

[0002] Metal corrosion refers to the process in which metals gradually lose their original quality and function due to chemical reactions between metals and corrosive media in the surrounding environment. Metal corrosion is a thermodynamically spontaneous process that causes huge economic losses to industrial equipment, infrastructure, and transportation. It is reported that the economic losses caused by metal corrosion each year account for 1.5%-2.4% of the gross national product. Therefore, controlling metal corrosion is of great significance for saving resources, protecting the environment, and maintaining property safety. Metal corrosion inhibitor is a substance that can prevent or slow down the corrosion of metals in environmental media at low concentrations. The use of corrosion inhibitors does not require special equipment or changes in the properties of metal components, and has the advantages of being economical, effective, and highly adaptable. Therefore, it is widely used in all aspects of industrial production and has become an important anti-corrosion technical means.

[0003] At present, the common traditional corrosion inhibitors on the market, such as inorganic corrosion inhibitors, mainly contain arsenic, cuprous chloride, iodide, nitrite and chromate, and organic corrosion inhibitors mainly include sulfonate type, monoimidazoline type, fatty amine, amide and its derivative type, thiazoline type and alkyl pyridine type. Although they have achieved certain results in metal corrosion control, these traditional corrosion inhibitors contain more or less toxic chemicals, which pose potential hazards to human body and environment. In order to solve the problems of traditional corrosion inhibitors, researchers have been working hard to develop new corrosion inhibitors that are more environmentally friendly and efficient. For example, many researchers use green natural products, such as modified sweet potato starch, walnut skin extract, modified lignin, etc., in combination with chemical corrosion inhibitors as metal corrosion inhibitors to reduce metal corrosion. The results show that these natural products show excellent slow-release performance after being compounded with chemical corrosion inhibitors. However, compound corrosion inhibitors still contain chemical reagents, which have a certain impact on the environment.

[0004] my country is a suitable area for tea cultivation, with a national tea planting area of ​​about 44 million mu. Pruning is an important measure in the comprehensive management of tea cultivation. Pruning can not only eliminate apical dominance, stimulate the germination of axillary buds, and obtain more new shoots, but also remove some branches with weak growth potential and pests and diseases, thereby ensuring better growth of tea trees. For a long time, the reuse of pruned branches of tea trees has mainly focused on the leaf part of the pruned branches, such as processing them into tea slices, tea powder, feed or auxiliary materials for edible fungus culture medium, etc. The lignified branches and trunks of pruned branches are mostly discarded in tea gardens or directly fueled, so that the pruned branches with pests and diseases are transferred, which aggravates the damage of pests and diseases in tea gardens, and at the same time causes waste of resources and restricts the improvement of economic benefits of tea gardens. The high-value utilization of tea pruning branches is of great significance to improving the economic benefits of tea gardens.

[0005] Alkaloids in plants contain functional groups with high charge density such as heteroatoms and aromatic rings (also a feature of the effectiveness of corrosion inhibitors), which can be adsorbed on metal surfaces by physical or chemical action to inhibit acid corrosion of metals. Macleaya cordata is a perennial plant of the genus Macleaya of the Papaveraceae family, which is widely distributed in my country and has the effects of insecticide, antipruritic, heat-clearing, and detoxification. Modern pharmacological and chemical composition studies have shown that the main active ingredient of Macleaya cordata is alkaloids, among which sanguinarine and chelerythrine are the two alkaloid components with the highest content. However, there is no research report on the use of Macleaya cordata alkaloids as corrosion inhibitors in the prior art. Summary of the invention

[0006] The technical problem to be solved by the present invention is that the existing traditional corrosion inhibitors contain more or less toxic chemicals, which cause potential harm to human body and environment. The present invention provides a green and environmentally friendly metal corrosion inhibitor and a preparation method thereof, wherein the metal corrosion inhibitor is a natural extract of tea tree pruning branches and Macleaya seeds without adding other chemicals.

[0007] The technical scheme of the present invention is: a bio-based metal corrosion inhibitor, which is prepared by mixing a tea tree branch extract and a Macleaya cordata pod extract, with the volume ratio of the two being 1:1-1:6.

[0008] The preparation method of the tea tree branch extract comprises the following steps: (1) washing and drying tea tree pruning branches; (2) crushing tea tree pruning branch materials; (3) preparing a tea tree pruning branch extraction solvent; (4) reacting tea tree pruning branches in a solvent; (5) filtering the reaction product at room temperature and pressure to separate liquid from solid; and (6) distilling the separated liquid to remove the organic acid solvent to obtain the tea tree branch extract.

[0009] In the step (1), the pruned tea branches include branches and leaves of tea trees from all origins and all varieties, and also branches and leaves of trees of all types, which are cleaned with tap water, dried at room temperature or air-dried at ≤40°C.

[0010] In the step (2), the tea tree pruning branch material is ground into a particle size of 80-120 μm.

[0011] The tea tree pruning branch extraction solvent is prepared by reacting a mixture of acetic acid: formic acid: hydrogen peroxide = 3:6:1-2:7:1 at 70-90° C. for 1-2 hours to obtain the tea tree pruning branch extraction solvent.

[0012] The tea tree pruning branches are reacted in a solvent: the tea tree pruning branch powder is extracted under normal pressure, a temperature of 70-90°C, a solid-liquid ratio (g / mL) of the tea tree pruning branch powder to the extraction solvent of 1:30-1:60, a mechanical stirring speed of 90-150rpm, and a depolymerization time of 6-10h.

[0013] The preparation method of the Macleaya oleifera pod extract comprises the following steps: (1) washing and drying the Macleaya oleifera pods; (2) crushing the Macleaya oleifera pods; and (3) performing an extraction reaction on the Macleaya oleifera pods, filtering the Macleaya oleifera pods, and concentrating the filtrate to obtain the Macleaya oleifera pod extract.

[0014] The crushed particle size of the Macleaya hui fruit pods and the fruit seeds in the fruit pods is 80-120 μm.

[0015] The extraction reaction of (3) Macleaya oleifera pods: Macleaya oleifera pod powder plus V 甲醇 :V 1％盐酸 =1:1 extract, solid-liquid ratio of 1:30-1:60 (g / mL), ultrasonic extraction at 60-80°C for 2-6 hours, filtration, and concentration of the filtrate to obtain the Macleaya cordata pod extract.

[0016] The beneficial effects of the present invention are as follows: 1. The present invention uses tea tree pruning branch extract and Macleaya oleifera pod extract to prepare a bio-based metal corrosion inhibitor. Different from the bio-based metal corrosion inhibitor prepared by compounding plant extracts and chemical substances, the present invention uses two plant extracts to compound, does not contain chemical products, and has the advantages of being environmentally friendly and easily degradable.

[0017] 2. The method used in the present invention is to use organic acid / hydrogen peroxide to depolymerize lignin and hemicellulose from tea tree pruning branches under normal pressure and near room temperature to prepare tea tree pruning branch extract, and to use methanol / 1% hydrochloric acid to extract alkaloids in Macleaya cordata pods under normal pressure and near room temperature to prepare Macleaya cordata pod extract. The production conditions are mild, the equipment requirements are low, the process is simple, the operation is convenient and reliable, the safety is strong, the production cost is low, and it is easy to large-scale industrial production.

[0018] 3. Organic acid / hydrogen peroxide and methanol can be reused through distillation;

[0019] 4. The bio-based metal corrosion inhibitor prepared by this method is mainly low molecular weight lignin fragments and alkaloids, which can be spontaneously degraded in nature.

[0020] 5. Different from the method of extracting biomass active ingredients from ethanol to prepare metal corrosion inhibitors, which is to dissolve a small part of the bioactive ingredients in ethanol, due to the low content of bioactive ingredients, additional chemical corrosion inhibitors must be added to improve the slow-release effect, which cannot achieve true green environmental protection. This method is to generate peracids through the reaction of organic acids and hydrogen peroxide, and the peracid oxidizes the β-O-4 bonds in the lignin of tea tree pruning branches, thereby achieving lignin depolymerization into low molecular weight lignin fragments. The lignin content obtained by this method is high, and at the same time, the alkaloids of Macleaya fruit pods are extracted by methanol / low concentration hydrochloric acid and compounded with lignin, which increases the plant extract on the metal surface, so there is no need to add additional chemical corrosion inhibitors to achieve a good slow-release effect. At the same time, the depolymerization residue is tea tree pruning branch cellulose, which can be sold directly, realizing the high added value utilization of tea tree pruning branches. DETAILED DESCRIPTION

[0021] 1. Washing and drying of pruned tea branches;

[0022] Pruned tea tree branches include branches and leaves of tea trees from all origins and all varieties, as well as branches and leaves of all types of trees. They should be washed clean with tap water, dried at room temperature or with forced air (≤40℃) to avoid carbonization of branches and leaves caused by excessively high temperatures.

[0023] 2. Crushing of tea tree pruning materials;

[0024] The particle size of the tea tree pruning material is preferably 80-120 μm. If the particle size is too small, residues will be left in the product during the later filtration, and if the particle size is too large, it will be unfavorable for the depolymerization of the tea tree pruning lignin and reduce the yield of the tea tree pruning extract.

[0025] 3. Preparation of solvent for extracting tea tree pruning branches;

[0026] A mixture of acetic acid: formic acid: hydrogen peroxide = 3:6:1-2:7:1 is reacted at 70-90° C. for 1-2 hours to obtain a tea tree pruning branch extraction solvent. The hydrogen peroxide is commercially available hydrogen peroxide containing 30% hydrogen peroxide; the organic acid includes saturated monocarboxylic acids such as formic acid, acetic acid, propionic acid, etc., with a purity of more than 98%.

[0027] 4. The pruned branches of tea trees react in a solvent;

[0028] The tea tree pruning branch powder is subjected to extraction reaction under normal pressure, temperature of 70-90°C, solid-liquid ratio of tea tree pruning branch powder to extraction solvent of 1:30-1:60, mechanical stirring speed of 90-150rpm, and depolymerization time of 6-10h. Lignin and hemicellulose of tea tree pruning branch powder are depolymerized into low molecular weight organic matter dissolved in extraction solvent for subsequent preparation of tea tree pruning branch extract, and tea tree pruning branch cellulose as a by-product of the method can be sold as a commodity.

[0029] 5. Filter the reaction product at normal temperature and pressure to separate the liquid and solid.

[0030] The low molecular weight organic matter solution obtained by depolymerization of tea tree pruning branch lignin and hemicellulose and the solid tea tree pruning branch cellulose are filtered and separated at normal temperature and pressure.

[0031] 6. distilling the separated liquid to remove the organic acid solvent to obtain a tea tree pruning branch extract;

[0032] The separated low molecular weight organic solution is distilled to extract organic acid for repeated use.

[0033] The reason for removing organic acids is that the presence of organic acids will affect the slow-release effect of metal corrosion inhibitors.

[0034] (II) Preparation of Macleaya oleifera pod (including seeds in pod) extract

[0035] 1. Washing and drying of the fruit pods of Bo Luo Hui;

[0036] The fruit pods of Boletus oleraceus include the fruit pods of Boletus oleraceus from all origins and all varieties, and also include the branches and leaves of all varieties of Boletus oleraceus. They should be cleaned with tap water, and air-dried at room temperature or with forced air (≤40°C) to avoid carbonization of the materials due to excessive temperature.

[0037] 2. Crushing of the fruit pods of Bo Luo Hui;

[0038] The crushing particle size of the fruit pods of Macleaya hui (including the seeds in the fruit pods) is preferably 80-120 μm. If the particle size is too small, residues will be left in the product during the later filtration, and if the particle size is too large, it will be unfavorable for the extraction of bioactive substances in the fruit pods of Macleaya hui, and reduce the yield of the Macleaya hui extract.

[0039] 3. Extraction reaction of Macleaya oleifera pods

[0040] Put the crushed Bo Luo Hui powder into a glass container and add V 甲醇 :V 1％盐酸 =1:1 (volume ratio) of the extract, the solid-liquid ratio (g / mL) of the Macleaya oleifera pod powder to the extract is 1:30-1:60, ultrasonic extraction is performed at 60-80° C. for 2-6 hours, filtration is performed, and the filtrate is concentrated to obtain the Macleaya oleifera pod extract.

[0041] (III) Preparation of bio-based metal corrosion inhibitors

[0042] The tea tree pruning branch extract and the Macleaya cordata pod extract are compounded in a volume ratio of 1:1-1:6 to prepare a bio-based metal corrosion inhibitor.

[0043] Application examples:

[0044] Application of the bio-based metal corrosion inhibitor in metal aluminum pickling:

[0045] Example 1:

[0046] The tea tree pruning branches were washed with tap water, placed in a blast drying oven at 40°C for 24 hours, and set aside. The dried tea tree pruning branches were crushed with a crusher to a particle size of 100 μm, packed and sealed, and placed in a desiccator for later use. 72 ml of acetic acid, 144 ml of formic acid, and 24 ml of hydrogen peroxide were added to the container respectively, stirred at 80°C at 120 rpm / min for 1 hour, and then 8 g of tea tree pruning branch powder was added, 8 drops of hydrochloric acid were dripped, and stirred at 80°C at 120 rpm / min for 8 hours. After the reaction was completed, it was naturally cooled to room temperature, filtered, and the filtrate was vacuum-evaporated to remove the organic acid solvent to obtain the tea tree pruning branch extract. The filter residue is tea tree pruning branch cellulose, which can be sold as a commodity.

[0047] The fruit pods of Macleaya cordata are cleaned with tap water, placed in a forced air drying oven at 40°C for 24 hours, and then used for standby. The dried fruit pods of Macleaya cordata are crushed with a crusher, the particle size of the fruit pods of Macleaya cordata is 100 μm, and the crushed fruit pods are sealed in a bag and placed in a desiccator for standby. 5 g of the crushed fruit pod powder of Macleaya cordata is placed in a container, 125 ml of methanol and 125 ml of 1% hydrochloric acid are added, and ultrasonic extraction is performed at 60°C for 2 hours, filtered, and the filtrate is evaporated to remove the solvent and concentrated to obtain the Macleaya cordata fruit pod extract.

[0048] The tea tree pruning branch extract and the Macleaya cordata pod extract were compounded in a volume ratio of 1:1 to prepare a bio-based metal corrosion inhibitor.

[0049] When in use, first polish the aluminum standard metal specimen with a length of 4 cm, a width of 4 cm, and a thickness of 4 mm with sandpaper, clean it, then put it into 50 mL of acetone and 50 mL of anhydrous ethanol in turn and wipe it with absorbent cotton, take it out and place it on a clean filter paper, dry it with filter paper, place it in a vacuum drying oven at 40 ° C for 2 hours, take it out and put it in a dryer for use. Pour 20 mL of 1 mol / L HCL into two containers (container A and container B) respectively, container A is the blank control group experiment, and container B is the test group experiment. Then add 1 mL of the above-mentioned bio-based metal corrosion inhibitor to container B, mix the corrosion inhibitor with 20 mL of 1 mol / L HCL, and then put the weighed aluminum sheet m into container A and container B respectively. A ,0 and m B ,0, put container A and container B in a constant temperature 30℃ water bath for 12h. Then take out the aluminum sheet, rinse it with distilled water, soak it in anhydrous ethanol for about 3min, take it out and place it on a clean filter paper, dry it with the filter paper, put it in a vacuum drying oven at 40℃ for 2h, and weigh it on an analytical balance to obtain the mass of the aluminum sheet m A and m B , The metal release rate calculated in this implementation case is 95.4%. The metal corrosion inhibitor of the present invention does not contain any substance harmful to the human body and the environment, will not cause pollution after use, and has a good use effect. Example 2:

[0050] The tea tree pruning branches were rinsed with tap water, placed in a blast drying oven at 40°C for 24 hours, and set aside. The dried tea tree pruning branches were crushed with a crusher to a particle size of 120μm, packed in bags and sealed, and placed in a desiccator for use. 80mL of acetic acid, 280mL of formic acid, and 40mL of hydrogen peroxide were added to the container respectively, stirred at 90°C at 150rpm / min for 1.5h, and then 8g of tea tree pruning branch powder was added, 8 drops of hydrochloric acid were dripped, and stirred at 90°C at 150rpm / min for 8h. After the reaction was completed, it was naturally cooled to room temperature, filtered, and the filtrate was vacuum-rotated to remove the organic acid solvent to obtain the tea tree pruning branch extract. The filter residue is tea tree pruning branch cellulose, which can be sold as a commodity.

[0051] The fruit pods of Macleaya oleifera were rinsed with tap water, placed in a forced air drying oven at 40°C for 24 hours, and then used for standby. The dried fruit pods of Macleaya oleifera were crushed with a crusher, the particle size of the crushed fruit pods of Macleaya oleifera was 120 μm, and the crushed fruit pods of Macleaya oleifera were sealed in a bag and placed in a desiccator for standby. 5 g of the crushed fruit pod powder of Macleaya oleifera was placed in a container, 100 ml of methanol and 100 ml of 1% hydrochloric acid were added, and ultrasonic extraction was performed at 70°C for 4 hours, filtered, and the filtrate was evaporated to remove the solvent and concentrated to obtain the Macleaya oleifera fruit pod extract.

[0052] Tea tree pruning branch extract and Macleaya cordata pod extract were compounded in a volume ratio of 1:5 to prepare a bio-based metal corrosion inhibitor.

[0053] When in use, first polish the aluminum standard metal specimen with a length of 4 cm, a width of 4 cm, and a thickness of 4 mm with sandpaper, clean it, then put it into 50 mL of acetone and 50 mL of anhydrous ethanol in turn and wipe it with absorbent cotton, take it out and place it on a clean filter paper, dry it with filter paper, place it in a vacuum drying oven at 40 ° C for 2 hours, take it out and put it in a dryer for use. Pour 20 mL of 1 mol / L HCL into two containers (container A and container B) respectively, container A is the blank control group experiment, and container B is the test group experiment. Then add 3 mL of the above-mentioned bio-based metal corrosion inhibitor to container B, mix the corrosion inhibitor with 20 mL of 1 mol / L HCL, and then put the weighed aluminum sheet m into container A and container B respectively. A ,0 and m B ,0, put container A and container B in a constant temperature 40℃ water bath for 18h. Then take out the aluminum sheet, rinse it with distilled water, soak it in anhydrous ethanol for about 3min, take it out and place it on a clean filter paper, dry it with the filter paper, put it in a vacuum drying oven at 40℃ for 2h, and weigh it on an analytical balance to obtain the mass of the aluminum sheet mA and m B , The metal release rate calculated in this implementation case is 96.6%. The metal corrosion inhibitor of the present invention does not contain any substance harmful to the human body and the environment, will not cause pollution after use, and has a good use effect. Example 3:

[0054] The tea tree pruning branches were washed with tap water, placed in a blast drying oven at 40°C for 24 hours, and set aside. The dried tea tree pruning branches were crushed with a crusher to a particle size of 120 μm, packed and sealed, and placed in a desiccator for later use. 120 mL of acetic acid, 240 mL of formic acid, and 40 mL of hydrogen peroxide were added to the container respectively, stirred at 85°C at 130 rpm / min for 2 hours, and then 8 g of tea tree pruning branch powder was added, 8 drops of hydrochloric acid were dripped, and stirred at 85°C at 130 rpm / min for 10 hours. After the reaction was completed, it was naturally cooled to room temperature, filtered, and the filtrate was vacuum-rotated to remove the organic acid solvent to obtain the tea tree pruning branch extract. The filter residue is tea tree pruning branch cellulose, which can be sold as a commodity.

[0055] The fruit pods of Macleaya oleifera were rinsed with tap water, placed in a forced air drying oven at 40°C for 24 hours, and then used for standby. The dried fruit pods of Macleaya oleifera were crushed with a crusher, the particle size of the crushed fruit pods of Macleaya oleifera was 120 μm, and the crushed fruit pods of Macleaya oleifera were sealed in a bag and placed in a desiccator for standby. 5 g of the crushed fruit pod powder of Macleaya oleifera was placed in a container, 150 ml of methanol and 150 ml of 1% hydrochloric acid were added, and ultrasonic extraction was performed at 80°C for 6 hours, filtered, and the filtrate was evaporated to remove the solvent and concentrated to obtain the Macleaya oleifera fruit pod extract.

[0056] Tea tree pruning branch extract and Macleaya cordata pod extract were compounded in a volume ratio of 1:4 to prepare a bio-based metal corrosion inhibitor.

[0057] When in use, first polish the aluminum standard metal specimen with a length of 4 cm, a width of 4 cm, and a thickness of 4 mm with sandpaper, clean it, then put it into 50 mL of acetone and 50 mL of anhydrous ethanol in turn and wipe it with absorbent cotton, take it out and place it on a clean filter paper, dry it with filter paper, place it in a vacuum drying oven at 40 ° C for 2 hours, take it out and put it in a dryer for use. Pour 20 mL of 1 mol / L HCL into two containers (container A and container B) respectively, container A is the blank control group experiment, and container B is the test group experiment. Then add 5 mL of the above-mentioned bio-based metal corrosion inhibitor to container B, mix the corrosion inhibitor with 20 mL of 1 mol / L HCL, and then put the weighed aluminum sheet m into container A and container B respectively. A,0 and m B,0, put container A and container B in a constant temperature 40℃ water bath for 20h. Then take out the aluminum sheet, rinse it with distilled water, soak it in anhydrous ethanol for about 3min, take it out and place it on a clean filter paper, dry it with the filter paper, put it in a vacuum drying oven at 40℃ for 2h, and weigh it on an analytical balance to obtain the mass of the aluminum sheet m A and m B , The metal slow-release rate calculated in this implementation case is 97.2%. The metal corrosion inhibitor of the present invention does not contain any substance harmful to the human body and the environment, does not cause pollution after use, and has a good use effect.

Claims

1. A bio-based metal corrosion inhibitor, characterized in that: The corrosion inhibitor is prepared by mixing tea tree branch extract and Macleaya cordata pod extract, with the volume ratio of the two being 1:1-1:

6.

2. A bio-based metal corrosion inhibitor according to claim 1, characterized in that: The preparation method of the tea tree branch extract comprises the following steps: (1) washing and drying tea tree pruning branches; (2) crushing tea tree pruning branch materials; (3) preparing a tea tree pruning branch extraction solvent; (4) reacting tea tree pruning branches in a solvent; (5) filtering the reaction product at room temperature and pressure to separate liquid from solid; and (6) distilling the separated liquid to remove the organic acid solvent to obtain the tea tree branch extract.

3. A bio-based metal corrosion inhibitor according to claim 2, characterized in that: In the step (1), the pruned tea branches include branches and leaves of tea trees from all origins and all varieties, and also branches and leaves of trees of all types, which are cleaned with tap water, dried at room temperature or air-dried at ≤40°C.

4. A bio-based metal corrosion inhibitor according to claim 2, characterized in that: In the step (2), the tea tree pruning branch material is ground into a particle size of 80-120 μm.

5. A bio-based metal corrosion inhibitor according to claim 2, characterized in that: The tea tree pruning branch extraction solvent is prepared by reacting a mixture of acetic acid: formic acid: hydrogen peroxide = 3:6:1 to 2:7:1 at 70-90° C. for 1-2 hours to obtain the tea tree pruning branch extraction solvent.

6. A bio-based metal corrosion inhibitor according to claim 2, characterized in that: The tea tree pruning branches are reacted in a solvent: the tea tree pruning branch powder is extracted under normal pressure, a temperature of 70-90°C, a solid-liquid ratio (g / mL) of the tea tree pruning branch powder to the extraction solvent of 1:30-1:60, a mechanical stirring speed of 90-150rpm, and a depolymerization time of 6-10h.

7. The bio-based metal corrosion inhibitor according to claim 1, characterized in that: The preparation method of the Macleaya oleifera pod extract comprises the following steps: (1) washing and drying the Macleaya oleifera pods; (2) crushing the Macleaya oleifera pods; and (3) performing an extraction reaction on the Macleaya oleifera pods, filtering the Macleaya oleifera pods, and concentrating the filtrate to obtain the Macleaya oleifera pod extract.

8. A bio-based metal corrosion inhibitor according to claim 7, characterized in that: The crushed particle size of the Macleaya hui fruit pods and the fruit seeds in the fruit pods is 80-120 μm.

9. The bio-based metal corrosion inhibitor according to claim 7, characterized in that: The extraction reaction of (3) Macleaya oleifera pods: Macleaya oleifera pod powder plus V 甲醇 :V 1％盐酸 =1:1 extract, solid-liquid ratio of 1:30-1:60 (g / mL), ultrasonic extraction at 60-80°C for 2-6 hours, filtration, and concentration of the filtrate to obtain the Macleaya cordata pod extract.