Preparation method and application of biomass metal corrosion inhibitor

Abstract

The invention discloses a preparation method of a biomass metal corrosion inhibitor. The preparation method is characterized by comprising the following steps: (1) washing and drying a biomass material; (2) crushing the biomass material; (3) preparing a biomass depolymerization solvent; (4) depolymerizing the biomass powder in a solvent; (5) filtering the depolymerized product at normal temperature and normal pressure to separate liquid from solid; and (6) rectifying the separated liquid to remove the organic acid solvent to obtain the metal corrosion inhibitor. The biomass is wood biomass such as passion fruit shells or straws. According to the method, organic acid reacts with hydrogen peroxide to generate peroxy acid, the peroxy acid oxidizes beta-O-4 bonds in the passion fruit shell or straw lignin, so that the lignin is depolymerized into lignin fragments with low molecular weight, the content of the lignin obtained by the method is high, and a good slow release effect can be achieved without additionally adding a chemical corrosion inhibitor. Meanwhile, the depolymerization residues are passion fruit shell or straw cellulose and can be directly sold, and high-added-value utilization of passion fruit shells or straw is achieved.

Description

Technical Field

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

[0002] Metal materials are widely used in various fields and are also indispensable raw materials in industrial production. However, due to the nature of metals, metals are prone to chemical or electrochemical reactions with environmental media and thus corroded, resulting in the destruction of metal material properties, resource loss and safety hazards. Using metal corrosion inhibitors to prevent metal corrosion is one of the best anti-corrosion methods in current industrial applications. Existing metal corrosion inhibitors mainly include inorganic corrosion inhibitors and organic corrosion inhibitors. Inorganic corrosion inhibitors mainly contain arsenic, cuprous chloride, iodide and various inorganic acid salts. Inorganic corrosion inhibitors have the following characteristics: (1) high toxicity, such as arsenic can easily cause human poisoning, nitrite, nitrate and chromate can easily cause cancer, endangering human and biological safety; (2) environmental unfriendly, phosphate can easily cause water oxidation, sulfate and borate can easily cause soil acidification; (3) fast consumption, and large amounts need to be added during use. Organic corrosion inhibitors mainly include fatty amines, amides and their derivatives, imidazolines, thiazolines, alkylpyridines, etc. Since these corrosion inhibitors are artificially synthesized organic compounds, they have certain harm to the environment.

[0003] Extracting natural products from plants as metal corrosion inhibitors has the advantages of low cost, environmental protection, practicality and biodegradability, which has attracted great attention from researchers. Many researchers use green natural products, such as modified sweet potato starch, walnut peel 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 properties after being compounded with chemical corrosion inhibitors. However, compound corrosion inhibitors still contain chemical reagents, which have a certain impact on the environment. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in view of the fact that existing metal corrosion inhibitors contain toxic chemical substances, which are easy to cause harm to human body and environment, the present invention provides a green and environmentally friendly biomass metal corrosion inhibitor and a preparation method thereof. The metal corrosion inhibitor is a natural extract of woody biomass such as passion fruit shell or straw, without adding other chemical substances.

[0005] The technical solution of the present invention is: a method for preparing a biomass metal corrosion inhibitor, comprising the following steps:

[0006] (1) washing and drying of biomass materials; (2) crushing of biomass materials; (3) preparation of biomass depolymerization solvent; (4) depolymerization of biomass powder in solvent; (5) filtering the depolymerization product at room temperature and pressure to separate the liquid and solid; (6) distilling the separated liquid to remove the organic acid solvent to obtain a metal corrosion inhibitor.

[0007] The biomass is all woody biomass raw materials such as passion fruit shells and straws.

[0008] In the step (1), the product is rinsed with tap water, dried at room temperature or dried with air at ≤40°C.

[0009] The biomass material has a crushing particle size of 80-120 μm.

[0010] The biomass depolymerization solvent is prepared by reacting a mixed solution of acetic acid: formic acid: hydrogen peroxide in a volume ratio of 3:6:1-2:7:1 at 80° C. for 1-2 hours to obtain the biomass depolymerization solvent.

[0011] The step (4) is as follows: depolymerizing the biomass powder under normal pressure, temperature of 70-90° C., solid-liquid ratio of biomass powder to depolymerization solvent of 1:30-1:60, mechanical stirring speed of 90-150 rpm, and depolymerization time of 6-10 hours.

[0012] In the step (5), the separated solid is washed, dried and sold as a high-purity cellulose raw material.

[0013] The metal corrosion inhibitor prepared by the method for preparing a biomass metal corrosion inhibitor is used to protect metal aluminum in acidic media.

[0014] Beneficial effects of the present invention: 1. The scheme of preparing bio-based metal corrosion inhibitors using an organic acid / hydrogen peroxide green solvent method in the present application is completely different in principle and technology from the use of ethanol solvent to extract biomass active ingredients as the composition of the metal corrosion inhibitor. The method used in the present invention is to use organic acid / hydrogen peroxide to depolymerize passion fruit shell or straw lignin and hemicellulose under normal pressure and near room temperature to prepare bio-based metal corrosion inhibitors. 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.

[0015] 2. Organic acid / hydrogen peroxide depolymerization solvent is green and environmentally friendly, and the organic acid can be reused through distillation;

[0016] 3. The biomass metal corrosion inhibitor prepared by this method is mainly low molecular weight lignin fragments, which can be spontaneously degraded in nature.

[0017] 4. The entire process does not discharge any solid or liquid pollutants or waste into the environment;

[0018] 5. Different from the method of extracting biomass active ingredients from ethanol to prepare metal corrosion inhibitors, which is to dissolve lignin in a small part of biomass in ethanol, due to the low content of dissolved lignin, 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 peracids oxidize the β-O-4 bonds in passion fruit shells or straw lignin, thereby achieving lignin depolymerization into low molecular weight lignin fragments. The lignin content obtained by this method is high, so no additional chemical corrosion inhibitors are needed to achieve a good slow-release effect. At the same time, the depolymerization residue is passion fruit shell cellulose or straw cellulose, which can be sold directly, realizing the high added value of passion fruit shells or straw.

[0019] 6. The depolymerization products of passion fruit shell (or straw) lignin and hemicellulose in the biomass metal corrosion inhibitor of the present invention are mostly organic macromolecules containing O atoms and N atoms. The organic macromolecules coordinate with the d empty orbitals of metal ions through O atoms and N atoms to form coordination bonds, and are adsorbed on the metal surface to form a dense adsorption film layer on the metal surface. The adsorption film layer isolates the acid corrosion medium from the metal Al surface, thereby slowing down the corrosion of the metal Al in the acid medium; DETAILED DESCRIPTION

[0020] 1. Washing and drying of passion fruit shells or straw materials; passion fruit shells include passion fruit shells from all origins and all varieties, and straw includes straw from all origins and all crops. Passion fruit shells or straws should be washed clean with tap water, and then air-dried at room temperature or with forced air (≤40°C) to avoid carbonization of passion fruit shells or straws due to excessive temperature.

[0021] 2. Crushing passion fruit shells or straw materials;

[0022] The particle size of passion fruit shell or straw material is preferably 80-120 μm. If the particle size is too small, there will be residues left in the product during the later filtration. If the particle size is too large, it is not conducive to the depolymerization of passion fruit shell or straw lignin, and reduces the yield of passion fruit shell or straw metal corrosion inhibitor.

[0023] 3. Preparation of passion fruit shell or straw depolymerization solvent;

[0024] A mixture of acetic acid: formic acid: hydrogen peroxide = 3:6:1 to 2:7:1 is reacted at 80°C for 1-2 hours to obtain a depolymerization 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, and propionic acid, with a purity of more than 98%.

[0025] 4. Depolymerization of passion fruit shell or straw powder in solvent;

[0026] Depolymerize the passion fruit shell or straw powder under normal pressure, temperature 70-90°C, solid-liquid ratio of passion fruit shell or straw powder to depolymerization solvent of 1:30-1:60, mechanical stirring speed 90-150rpm, depolymerization time 6-10h. Depolymerize the passion fruit shell or straw powder lignin and hemicellulose into low molecular weight organic matter in the solution for subsequent preparation of passion fruit shell or straw metal corrosion inhibitor, and passion fruit shell or straw cellulose as a by-product of the method can be sold as a commodity.

[0027] 5. Filter the depolymerization product at normal temperature and pressure to separate the liquid and solid.

[0028] The low molecular weight organic matter solution obtained by depolymerizing passion fruit shell or straw lignin and hemicellulose and the solid passion fruit shell cellulose or straw cellulose are filtered and separated at normal temperature and pressure.

[0029] 6. Distilling the separated liquid to remove the organic acid solvent to obtain passion fruit shell or straw metal corrosion inhibitor;

[0030] The separated low molecular weight organic solution is distilled to extract organic acid for reuse. The reason for removing organic acid is that the presence of organic acid will affect the slow release effect of metal corrosion inhibitor.

[0031] 7. The separated solids are washed, dried and sold as high-purity cellulose raw materials.

[0032] The application of the biomass metal corrosion inhibitor such as passion fruit shell or straw is the application of the metal corrosion inhibitor to protect metal aluminum in acidic medium.

[0033] The specific implementation methods are as follows:

[0034] Example 1

[0035] The passion fruit shell was washed with tap water, placed in a blast drying oven at 40°C for 24 hours, and set aside. The dried passion fruit shell was crushed with a crusher to a particle size of 100 μm, packed and sealed, and placed in a dryer for use. 72 mL of acetic acid, 144 mL of formic acid, and 24 mL of hydrogen peroxide were added to the container, stirred at 80°C at 150 rpm / min for 1 hour, and then 8 g of passion fruit shell powder was added, 8 drops of concentrated hydrochloric acid were dripped, and stirred at 80°C at 150 rpm / min for 6 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 a passion fruit shell metal corrosion inhibitor. The filter residue is passion fruit shell cellulose, which can be sold as a commodity.

[0036] The operation of this embodiment is simple. When in use, first polish the aluminum standard metal test piece 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 2h, take it out and put it in a dryer for use. Pour 20mL of 1mol / L HCL into two containers (container A and container B) respectively, container A is a blank control group experiment, and container B is a test group experiment. Then add 1mL of passion fruit shell metal corrosion inhibitor to container B, mix the corrosion inhibitor with 20mL1mol / 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 25℃ 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 slow-release rate calculated in this implementation case is 95.6%. 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.

[0037] Example 2:

[0038] The passion fruit shell was washed with tap water, placed in a blast drying oven at 40°C for 24 hours, and set aside. The dried passion fruit shell was crushed with a crusher, the crushing particle size was 120μm, the bag was sealed, and placed in a dryer for use. 96mL of acetic acid, 192mL of formic acid, and 32mL of hydrogen peroxide were added to the container respectively, stirred at 80°C at 150rpm / min for 2h, and then 8g of passion fruit shell powder was added, 10 drops of concentrated hydrochloric acid were dripped, and the reaction was stirred at 80°C at 150rpm / 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 a passion fruit shell metal corrosion inhibitor. The filter residue is passion fruit shell cellulose, which can be sold as a commodity.

[0039] 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 2 mL of passion fruit shell 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 35℃ water bath for 24h. 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 96.4%. 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.

[0040] Example 3:

[0041] The passion fruit shell was washed with tap water, placed in a blast drying oven at 40°C for 24 hours, and set aside. The dried passion fruit shell was crushed with a crusher, the crushing particle size was 90μm, the bag was sealed, and placed in a dryer for use. 120mL of acetic acid, 240mL of formic acid, and 40mL of hydrogen peroxide were added to the container respectively, stirred at 80°C at 150rpm / min for 2h, and then 10g of passion fruit shell powder was added, 20 drops of concentrated hydrochloric acid were dripped, and the reaction was stirred at 80°C at 150rpm / min for 10 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 a passion fruit shell metal corrosion inhibitor. The filter residue is passion fruit shell cellulose, which can be sold as a commodity.

[0042] 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 passion fruit shell 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 35℃ 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 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.

[0043] Example 4:

[0044] Wash the straw with tap water, place it in a blast drying oven at 40°C and dry it for 24 hours for later use. Crush the dried straw with a crusher to a particle size of 100μm, seal it in a bag, and place it in a desiccator for later use. Add 72mL of acetic acid, 144mL of formic acid, and 24mL of hydrogen peroxide to the container, stir and react at 80°C at 150rpm / min for 1h, then add 8g of straw, drip 8 drops of concentrated hydrochloric acid, stir and react at 80°C at 150rpm / min for 6h, cool naturally to room temperature after the reaction, filter, and vacuum evaporate the filtrate to remove the organic acid solvent to obtain straw metal corrosion inhibitor. The filter residue is straw cellulose, which can be sold as a commodity.

[0045] The operation of this embodiment is simple. When in use, first polish the aluminum standard metal test piece 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 straw 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 25℃ 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 slow-release rate calculated in this implementation case is 95%. 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 method for preparing a biomass metal corrosion inhibitor, characterized in that: The method comprises the following steps: (1) washing and drying biomass materials; (2) crushing biomass materials; (3) preparing a biomass depolymerization solvent; (4) depolymerizing biomass powder in a solvent; (5) filtering the depolymerization product at room temperature and pressure to separate liquid and solid; and (6) distilling the separated liquid to remove the organic acid solvent to obtain a metal corrosion inhibitor. The biomass is passion fruit shell or straw.

2. The method for preparing a biomass metal corrosion inhibitor according to claim 1, characterized in that: In the step (1), the product is rinsed with tap water, dried at room temperature or dried with air at ≤40°C.

3. The method for preparing a biomass metal corrosion inhibitor according to claim 1, characterized in that: The biomass material has a crushing particle size of 80-120 μm.

4. The method for preparing a biomass metal corrosion inhibitor according to claim 1, characterized in that: The biomass depolymerization solvent is prepared by reacting a mixed solution of acetic acid: formic acid: hydrogen peroxide in a volume ratio of 3:6:1-2:7:1 at 80° C. for 1-2 hours to obtain the biomass depolymerization solvent.

5. The method for preparing a biomass metal corrosion inhibitor according to claim 1, characterized in that: The step (4) is as follows: depolymerizing the biomass powder under normal pressure, temperature of 70-90° C., solid-liquid ratio of biomass powder to depolymerization solvent of 1:30-1:60, mechanical stirring speed of 90-150 rpm, and depolymerization time of 6-10 hours.

6. The method for preparing a biomass metal corrosion inhibitor according to claim 1, characterized in that: In the step (5), the separated solid is washed, dried and sold as a high-purity cellulose raw material.

7. Application of the metal corrosion inhibitor prepared by the method for preparing a biomass metal corrosion inhibitor as described in any one of claims 1 to 6 for protecting metal aluminum in acidic media.