Solanum nigrum stem and leaf compounded steel bar corrosion inhibitor as well as preparation method and application thereof
By combining the extract of the stem and leaf of the sunflower stem and leaf of the sunflower with potassium benzoate and magnesium oxide, a multi-component rust inhibitor is formed, which solves the problem of corrosion of the reinforced concrete structure in the chloride environment, and achieves an efficient and environmentally friendly rust inhibition effect, especially in severe chloride-induced erosion environments such as coastal bridges, which significantly enhances the durability and protective performance of the concrete structure.
Patent Information
- Application Number
- CN202510456329.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2025-08-01
AI Technical Summary
The existing reinforced concrete structures are prone to corrosion in an environment rich in chloride salt. Traditional rust inhibitors have problems such as high cost, poor environmental protection and difficulty in degradation. The rust resistance performance of single santhemum stem and leaf extract is unstable in the long-term chloride salt erosion environment.
The extract of the stem and leaf of the sunflower is combined with potassium benzoate and magnesium oxide to form a multi-component rust inhibitor, and a protective film is formed through a polyhydroxy structure and the surface of the steel bar. Combined with potassium benzoate to form a dense film in the anode area. Magnesium oxide increases the alkalinity of the concrete pore liquid and coordinates the rust resistance performance.
It has achieved low-cost, efficient and environmentally friendly steel bar rust resistance, especially in severe chloride erosion environments such as coastal bridges, which significantly enhance the durability and protective performance of concrete structures and reduce maintenance costs.
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Figure CN120398452A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of building materials, and particularly relates to a rust inhibitor for reinforcing steel bars compounded with Solanum nigrum stems and leaves, a preparation method thereof, and an application thereof. Background Art
[0002] In an environment rich in chlorides, the corrosion of reinforcing steel bars is one of the main reasons for the deterioration of reinforced concrete structures. Therefore, improving the corrosion resistance of reinforcing steel bars in concrete structures under chloride environments has become an urgent problem to be solved.
[0003] Among numerous protective measures, rust inhibitors are widely used due to their simplicity and economy. Currently, rust inhibitors are mainly divided into three categories: inorganic types (such as chromates, nitrites, and phosphates), organic types (such as amines and alkanolamines), and mixed rust inhibitors. However, inorganic rust inhibitors often cause environmental pollution, while organic rust inhibitors are limited by their high preparation costs. Mixed rust inhibitors improve the rust inhibition effect through the synergistic action of multiple components, but in practical applications, they often face challenges such as high synthesis costs, poor environmental friendliness, and difficulty in degradation. Therefore, developing a compound rust inhibitor for reinforcing steel bars with low cost, high efficiency, and environmental friendliness has become a current research hotspot.
[0004] Solanum nigrum ( Solanum nigrum L. ) is common in most parts of China. Its fruits have high medicinal value, but Solanum nigrum stems and leaves are often discarded, causing waste of resources. Solanum nigrum stems and leaves are rich in polyphenolic compounds, including gentisic acid, luteolin, apigenin, kaempferol, m-coumaric acid, etc. Their polyhydroxy structures can form a protective film on the surface of reinforcing steel bars through adsorption and chelation, delaying corrosion. At the same time, its advantages of being green, environmentally friendly, and easily degradable conform to the concept of sustainable development, and it is a theoretical rust inhibitor for reinforcing steel bars. However, the rust inhibition effect of a single extract of Solanum nigrum stems and leaves has certain limitations in practical applications, especially for reinforced concrete structures (such as coastal bridges, etc.) that are long-term exposed to chloride erosion environments. A single rust inhibition component is difficult to form a stable protective film on the surface of reinforcing steel bars, and its rust inhibition performance is easily affected by external environmental changes, resulting in failure. Summary of the Invention
[0005] In order to solve the above problems, the present invention provides a rust inhibitor for reinforcing steel bars compounded with Solanum nigrum stems and leaves, a preparation method thereof, and an application thereof.
[0006] The first object of the present invention is to provide a rust inhibitor for reinforcing steel bars compounded with Solanum nigrum stems and leaves, which includes the following components in parts by mass: 20 - 40 parts of Solanum nigrum stem and leaf extract, 5 - 10 parts of potassium benzoate, 1 - 2 parts of magnesium oxide, and 20 - 50 parts of water.
[0007] Preferably, it is 40 parts of Solanum nigrum stem and leaf extract, 5 parts of the potassium benzoate, 1 part of the magnesium oxide, and 40 parts of the water.
[0008] Preferably, the extract of Solanum nigrum stems and leaves includes 2,5-dihydroxybenzoic acid, 2-(3,4-dihydroxyphenyl)-5,7-dihydroxybenzofuran-4-one, 5,7-dihydroxy-2-(4-hydroxyphenyl)benzofuran-4-one, 3,5,7-trihydroxy-2-(4-hydroxyphenyl)benzofuran-4-one, and (E)-3-(3-hydroxyphenyl)-2-acrylic acid.
[0009] Preferably, the preparation method of the Solanum nigrum stems and leaves compound steel rust inhibitor is as follows: weigh each component, stir and mix evenly at room temperature; The preparation method of the extract of Solanum nigrum stems and leaves includes the following steps: S1: Select Solanum nigrum stems and leaves as raw materials, wash them with clean water, dry, crush, and sieve to obtain Solanum nigrum stems and leaves powder; S2: Add the Solanum nigrum stems and leaves powder into an ethanol solution, fully soak it at room temperature and then carry out reflux extraction; after extraction, carry out vacuum filtration to collect the filtrate; S3: Concentrate the filtrate to obtain a concentrated solution; dry the concentrated solution to obtain the extract of Solanum nigrum stems and leaves.
[0010] Preferably, in step S2, the liquid-to-material ratio of the Solanum nigrum stems and leaves powder to the ethanol solution is 15-20 mL: 1 g.
[0011] Preferably, in step S2, the ethanol concentration in the ethanol solution is 65-75%; the time for fully soaking at room temperature is 40-60 min.
[0012] Preferably, in step S2, the temperature of the reflux extraction is 70-75 °C, the number of reflux extraction times is 3-4 times, and the extraction time for each time is 40-50 min.
[0013] Preferably, the drying in step S1 is specifically drying by baking, the baking temperature is 60-65 °C, and the time is 10-15 h; the sieving is through a 100-mesh sieve.
[0014] Preferably, the drying in step S3 is specifically vacuum drying, the drying temperature is 60-65 °C, the vacuum degree is 300 Pa, and the drying time is 5-8 h.
[0015] The second object of the present invention is to provide an application of the Solanum nigrum stems and leaves compound steel rust inhibitor in delaying the corrosion of steel bars. The Solanum nigrum stems and leaves compound steel rust inhibitor is incorporated into reinforced concrete, and the incorporation amount accounts for 0.025-0.1% of the mass of the cementitious material in the reinforced concrete.
[0016] Compared with the prior art, the present invention can achieve the following beneficial effects: In view of the problems existing in the prior art, the present invention proposes a rust inhibitor for steel bars compounded with the stems and leaves of Solanum nigrum. By compounding the extract of the stems and leaves of Solanum nigrum with auxiliary components such as potassium benzoate and magnesium oxide, the comprehensive performance of the rust inhibitor is effectively enhanced. Specifically, the polyphenolic compounds in the extract of the stems and leaves of Solanum nigrum form a coordination chelation with iron ions on the surface of the steel bar through their polyhydroxy structure, generating an organic protective film; potassium benzoate, as an anodic rust inhibitor component, forms a dense organic film in the anodic region of the steel bar, reducing the anodic reaction; magnesium oxide generates magnesium hydroxide after contacting with water, increasing the alkalinity of the pore solution of the concrete and promoting the formation of a passive film on the surface of the steel bar. The synergistic effect of these three components not only effectively inhibits the anodic reaction during the corrosion process of the steel bar, but also resists the erosion of chloride ions through a stable protective film, thus significantly improving the rust inhibition performance and the durability of the concrete structure. The rust inhibitor for steel bars compounded with the stems and leaves of Solanum nigrum of the present invention has the advantages of low cost, strong environmental protection, good persistence, etc., and is particularly suitable for reinforced concrete structures severely eroded by chloride salts such as coastal bridges. Compared with traditional nitrite rust inhibitors, the rust inhibitor of the present invention is non-toxic, pollution-free, does not contain carcinogenic substances, and is more friendly to the environment.
[0017] In summary, the present invention realizes the efficient development and low-cost utilization of resources by extracting the effective components of the stems and leaves of Solanum nigrum, and has significant ecological and economic benefits. The rust inhibitor of the present invention has a small dosage and low cost, can generate a dense protective film on the surface of the steel bar, and effectively inhibits the corrosion of the steel bar. The rust inhibitor is directly incorporated into the concrete without complex treatment processes, has strong adaptability to the concrete and does not affect its performance. Especially in structures severely eroded by chloride ions such as coastal bridges, it shows excellent protection effects, can significantly enhance the durability of the concrete structure, extend the service life and reduce the maintenance cost. In addition, the development of this rust inhibitor also realizes the efficient utilization of waste resources of the stems and leaves of Solanum nigrum, with both economic and ecological benefits, providing a new solution for improving the durability of reinforced concrete structures. Brief Description of the Drawings
[0018] Figure 1 is a flowchart of the preparation method of the extract of the stems and leaves of Solanum nigrum provided by an embodiment of the present invention.
[0019] Figure 2 is the electrochemical impedance spectrum of the electrode of the steel bar added with the rust inhibitor for steel bars compounded with the stems and leaves of Solanum nigrum in a test environment with a NaCl mass fraction of 1%.
[0020] Figure 3 is the Tafel dynamic potential polarization curve of the steel bar added with the rust inhibitor for steel bars compounded with the stems and leaves of Solanum nigrum in a test environment with a NaCl mass fraction of 1%. Detailed Embodiments
[0021] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed descriptions will not be repeated.
[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.
[0023] The present invention provides a compound steel bar rust inhibitor of Solanum nigrum stems and leaves, which comprises the following components in parts by mass: 20 - 40 parts of Solanum nigrum stems and leaves extract, 5 - 10 parts of potassium benzoate, 1 - 2 parts of magnesium oxide, and 20 - 50 parts of water; In a specific embodiment, it is 20 parts of Solanum nigrum stems and leaves extract, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 20 parts of water; or 26 parts of Solanum nigrum stems and leaves extract, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 25 parts of water; or 30 parts of Solanum nigrum stems and leaves extract, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 25 parts of water; or 30 parts of Solanum nigrum stems and leaves extract, 6 parts of potassium benzoate, 1 part of magnesium oxide, and 32 parts of water; or 30 parts of Solanum nigrum stems and leaves extract, 5 parts of potassium benzoate, 2 parts of magnesium oxide, and 30 parts of water; or 30 parts of Solanum nigrum stems and leaves extract, 7 parts of potassium benzoate, 1 part of magnesium oxide, and 34 parts of water; or 35 parts of Solanum nigrum stems and leaves extract, 5 parts of potassium benzoate, 2 parts of magnesium oxide, and 34 parts of water; or 35 parts of Solanum nigrum stems and leaves extract, 6 parts of potassium benzoate, 1 part of magnesium oxide, and 35 parts of water; or 40 parts of Solanum nigrum stems and leaves extract, 8 parts of potassium benzoate, 1 part of magnesium oxide, and 35 parts of water; or 40 parts of Solanum nigrum stems and leaves extract, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 40 parts of water; The main components of the Solanum nigrum stems and leaves extract include 2,5 - dihydroxybenzoic acid, 2-(3,4 - dihydroxyphenyl)-5,7 - dihydroxybenzofuran - 4 - one, 5,7 - dihydroxy - 2-(4 - hydroxyphenyl)benzofuran - 4 - one, 3,5,7 - trihydroxy - 2-(4 - hydroxyphenyl)benzofuran - 4 - one, (E)-3-(3 - hydroxyphenyl)-2 - acrylic acid; The preparation method of the compound steel bar rust inhibitor of Solanum nigrum stems and leaves is: weighing each component and stirring and mixing evenly at room temperature; The preparation method of the Solanum nigrum stems and leaves extract comprises the following steps: S1: Select the stems and leaves of Solanum nigrum as raw materials, wash them with clean water, dry, crush, and sieve them to obtain Solanum nigrum stem and leaf powder; Specifically, the drying method is drying in an oven, the drying temperature is 60 - 65 °C, and the time is 10 - 15 h; the crushing is carried out by grinding and crushing with a high-speed grinder; the sieving is through a 100-mesh sieve; S2: Add the Solanum nigrum stem and leaf powder into an ethanol solution, fully soak it at room temperature and then carry out reflux extraction; after extraction, carry out vacuum filtration and collect the filtrate; Specifically, the liquid-to-material ratio of the Solanum nigrum stem and leaf powder to the ethanol solution is 15 - 20 mL:1 g; the ethanol concentration in the ethanol solution is 65 - 75%; the time for fully soaking at room temperature is 40 - 60 min; the temperature for reflux extraction is 70 - 75 °C, the number of reflux extraction times is 3 - 4 times, and the extraction time for each time is 40 - 50 min; S3: Concentrate the filtrate to obtain a concentrated solution; dry the concentrated solution to obtain the Solanum nigrum stem and leaf extract; Specifically, the concentration is carried out by rotary evaporation, the temperature of rotary evaporation is 60 - 65 °C, and the time is 1 - 2 h; the drying method is vacuum drying, the drying temperature is 60 - 65 °C, the vacuum degree is 300 Pa, and the drying time is 5 - 8 h (see the preparation flow chart in Figure 1 )
[0024] Example 1 This example provides a preparation method of Solanum nigrum stem and leaf extract, which specifically includes the following steps: S1: Select the stems and leaves of Solanum nigrum as raw materials, wash them with clean water, place them in an oven at 60 °C, dry for 15 h, grind and crush them, and sieve through a 100-mesh sieve to remove larger particles to obtain Solanum nigrum stem and leaf powder.
[0025] S2: Add the Solanum nigrum stem and leaf powder into an ethanol solution with a concentration of 65% according to the liquid-to-material ratio of 20 mL:1 g, soak it at room temperature for 40 min, carry out reflux extraction at 70 °C for 4 times, 40 min each time; after extraction, carry out vacuum filtration to obtain the filtrate; S3: Place the filtrate in a rotary evaporator for heating and concentration to obtain a concentrated solution; place the concentrated solution in a vacuum dryer, evacuate to 300 Pa, and dry at 60 °C for 8 h to obtain the Solanum nigrum stem and leaf extract.
[0026] Example 2 This example provides a preparation method of Solanum nigrum stem and leaf extract, which specifically includes the following steps: S1: Select the stems and leaves of Solanum nigrum as raw materials, wash them with clean water, place them in an oven at 65 °C, dry for 13 h, grind and crush them, and sieve through a 100-mesh sieve to remove larger particles to obtain Solanum nigrum stem and leaf powder.
[0027] S2: Add the powder of Solanum nigrum stems and leaves to ethanol solution with a concentration of 70% at a liquid-to-solid ratio of 18 mL:1 g, soak it at room temperature for 55 min, reflux and extract it 3 times at 75 °C for 50 min each time; after extraction, filter it under reduced pressure to obtain the filtrate. S3: Place the filtrate in a rotary evaporator to heat and concentrate it to obtain a concentrated solution; place the concentrated solution in a vacuum dryer, evacuate to 300 Pa, and dry it at 62 °C for 7 h to obtain the extract of Solanum nigrum stems and leaves.
[0028] Example 3 This example provides a method for preparing an extract of Solanum nigrum stems and leaves, which specifically includes the following steps: S1: Select Solanum nigrum stems and leaves as raw materials, wash them with clean water, place them in an oven at 65 °C, dry them continuously for 12 h, grind and crush them, and pass them through a 100-mesh sieve to remove larger particles to obtain the powder of Solanum nigrum stems and leaves.
[0029] S2: Add the powder of Solanum nigrum stems and leaves to ethanol solution with a concentration of 70% at a liquid-to-solid ratio of 18 mL:1 g, soak it at room temperature for 55 min, reflux and extract it 4 times at 75 °C for 40 min each time; after extraction, filter it under reduced pressure to obtain the filtrate. S3: Place the filtrate in a rotary evaporator to heat and concentrate it to obtain a concentrated solution; place the concentrated solution in a vacuum dryer, evacuate to 300 Pa, and dry it at 60 °C for 7 h to obtain the extract of Solanum nigrum stems and leaves.
[0030] Example 4 This example provides a compound steel bar rust inhibitor of Solanum nigrum stems and leaves, which includes the following components by mass: 20 parts of the extract of Solanum nigrum stems and leaves, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 20 parts of water; the preparation method of the extract of Solanum nigrum stems and leaves is the same as that in Example 1.
[0031] Example 5 This example provides a compound steel bar rust inhibitor of Solanum nigrum stems and leaves, which includes the following components by mass: 26 parts of the extract of Solanum nigrum stems and leaves, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 25 parts of water; the preparation method of the extract of Solanum nigrum stems and leaves is the same as that in Example 2.
[0032] Example 6 This example provides a compound steel bar rust inhibitor of Solanum nigrum stems and leaves, which includes the following components by mass: 30 parts of the extract of Solanum nigrum stems and leaves, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 25 parts of water; the preparation method of the extract of Solanum nigrum stems and leaves is the same as that in Example 3.
[0033] Example 7 This example provides a compound steel bar rust inhibitor of Solanum nigrum stems and leaves, which includes the following components by mass: 30 parts of the extract of Solanum nigrum stems and leaves, 6 parts of potassium benzoate, 1 part of magnesium oxide, and 32 parts of water; the preparation method of the extract of Solanum nigrum stems and leaves is the same as that in Example 1.
[0034] Example 8 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 30 parts of Solanum nigrum L. stems and leaves extract, 5 parts of potassium benzoate, 2 parts of magnesium oxide, and 30 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 3.
[0035] Example 9 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 30 parts of Solanum nigrum L. stems and leaves extract, 7 parts of potassium benzoate, 1 part of magnesium oxide, and 34 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 1.
[0036] Example 10 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 35 parts of Solanum nigrum L. stems and leaves extract, 5 parts of potassium benzoate, 2 parts of magnesium oxide, and 34 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 1.
[0037] Example 11 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 35 parts of Solanum nigrum L. stems and leaves extract, 6 parts of potassium benzoate, 1 part of magnesium oxide, and 35 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 1.
[0038] Example 12 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 40 parts of Solanum nigrum L. stems and leaves extract, 8 parts of potassium benzoate, 1 part of magnesium oxide, and 35 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 1.
[0039] Example 13 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 40 parts of Solanum nigrum L. stems and leaves extract, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 40 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 1.
[0040] Example 14 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 40 parts of Solanum nigrum L. stems and leaves extract, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 40 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 2.
[0041] Example 15 This example provides a compound steel bar rust inhibitor with Solanum nigrum L. stems and leaves, which includes the following components by mass fraction: 40 parts of Solanum nigrum L. stems and leaves extract, 5 parts of potassium benzoate, 1 part of magnesium oxide, and 40 parts of water; the preparation method of the Solanum nigrum L. stems and leaves extract is the same as that in Example 3.
[0042] Example 16 Application example: A compound steel bar rust inhibitor of Solanum nigrum stems and leaves prepared in Example 15 above was incorporated into reinforced concrete, and the rust inhibition performance of the steel bars added with the rust inhibitor was evaluated. The specific process is as follows: The compound steel bar rust inhibitor of Solanum nigrum stems and leaves was added to the simulated concrete pore solution at different addition amounts (0.1%, 0.05%, 0) respectively to prepare Test Sample 1, Test Sample 2 and the control group. The corrosion performance of Test Sample 1, Test Sample 2 and the control group was tested, and then the rust inhibition performance of the rust inhibitor at different addition amounts on the steel bars was evaluated. The sample preparation is as follows: I. Sample preparation 1. Prepare Test Sample 1: Cut out a cylindrical Q235 steel bar with a diameter of 8.0 mm and a height of 10.0 mm, place it in a PVC pipe, and fill the gap between the steel bar block and the PVC pipe with epoxy resin. Then select one plane of the steel bar block as the working surface, polish it step by step with sandpaper, wash it with distilled water and degrease it with ethanol to make the working surface present a mirror state. Use phosphoric acid solution and sodium hydroxide solution to adjust the pH of the saturated calcium hydroxide solution at 25 °C to 12.0 as the simulated concrete pore solution. Add a compound steel bar rust inhibitor of Solanum nigrum stems and leaves prepared in Example 15 above to the simulated concrete pore solution at a mass fraction of 0.1% to prepare Test Sample 1. Seal Test Sample 1 and conduct corrosion performance testing.
[0043] 2. Prepare Test Sample 2: Cut out a cylindrical Q235 steel bar with a diameter of 8.0 mm and a height of 10.0 mm, place it in a PVC pipe, and fill the gap between the steel bar block and the PVC pipe with epoxy resin. Then select one plane of the steel bar block as the working surface, polish it step by step with sandpaper, wash it with distilled water and degrease it with ethanol to make the working surface present a mirror state. Use phosphoric acid solution and sodium hydroxide solution to adjust the pH of the saturated calcium hydroxide solution at 25 °C to 12.0 as the simulated concrete pore solution. Add a compound steel bar rust inhibitor of Solanum nigrum stems and leaves prepared in Example 15 above to the simulated concrete pore solution at a mass fraction of 0.05% to prepare Test Sample 2. Seal Test Sample 2 and conduct corrosion performance testing.
[0044] 3. Preparation of the control group: Cut out a Q235 steel bar in the shape of a cylinder with a diameter of 8.0 mm and a height of 10.0 mm, place it in a PVC pipe, and use epoxy resin to fill the gap between the steel bar block and the PVC pipe. Then, select one plane of the steel bar block as the working surface, polish it step by step with sandpaper, wash it with distilled water, and degrease it with ethanol to make the working surface present a mirror state; use phosphoric acid solution and sodium hydroxide solution to adjust the pH of the saturated calcium hydroxide solution at 25 °C to 12.0 as the simulated concrete pore solution; no Solanum nigrum stem and leaf compound steel bar rust inhibitor is added to this simulated concrete pore solution, and this sample is used as the control group, and the corrosion performance test is also carried out.
[0045] II. Performance testing Use a CS350 electrochemical workstation. The test system adopts a typical three-electrode system (that is, the steel bar is the working electrode, the platinum electrode is the auxiliary electrode, and the mercury / mercuric oxide electrode is used as the reference electrode) to test the electrochemical impedance spectrum and Tafel dynamic potential polarization curve of test sample 1, test sample 2 and the control group, and then evaluate the corrosion inhibition performance of the rust inhibitor with different addition amounts on the steel bar; the specific test conditions and results are as follows: 1. Test the electrochemical impedance spectrum The electrochemical impedance spectrum is to apply a small-amplitude alternating potential wave with different frequencies to the electrochemical system, measure the ratio of the alternating potential to the current signal (this ratio is the impedance of the system) as a function of the sine wave frequency, or the phase angle of the impedance as a function of the sine wave frequency, and then analyze the mechanisms of electrode materials, solid electrolytes, conductive polymers, and corrosion protection. In this experiment, the electrochemical impedance spectrum test uses a sine alternating voltage with a perturbation amplitude of 10 mV, and the test frequency range is 0.01 Hz to 10,000 Hz. The Zview software is used to fit and organize the measured data.
[0046] The test results are as Figure 2 ; Figure 2 is the Nyquist plot, which is a representation of the electrochemical impedance spectrum. It plots the real part of the impedance on the abscissa and the imaginary part of the impedance on the ordinate. The larger the radius of the capacitive semicircle of the impedance spectrum, the greater the polarization resistance of the steel bar electrode, and the better the rust removal effect of the corresponding steel bar rust inhibitor. Figure 2 The three curves in it respectively represent the electrochemical impedance spectra of the steel bar electrodes of test sample 1, test sample 2 and the control group when the mass fraction of NaCl in the test environment is 1%. The curve of test sample 1 has the largest radius, the polarization resistance of the steel bar is the largest, and the corrosion resistance is the best. The curve radius of test sample 2 is the second, and the curve radius of the control group is the smallest. It can be seen that adding a Solanum nigrum stem and leaf compound steel bar rust inhibitor prepared in Example 15 with a mass fraction of 0.05% or 0.1% to the simulated concrete pore solution significantly improves the corrosion resistance of the steel bar. The steel bar rust inhibitor prepared from Solanum nigrum stem and leaf has excellent rust inhibition effect on the steel bar.
[0047] 2. Testing Tafel potentiodynamic polarization curves The scanning potential for the Tafel potentiodynamic polarization curve test is ±250 mV relative to the open circuit potential, and the scanning rate is 1 mV / s. To obtain better results, the Tafel potentiodynamic polarization curve test under each test condition is repeated at least three times.
[0048] The test results are as Figure 3 。 Figure 3 Among them, the three curves respectively represent the Tafel potentiodynamic polarization curves of Test Sample 1, Test Sample 2, and the control group when the mass fraction of NaCl in the test environment is 1%. The self-corrosion current density of the control group is 1.410 μA / cm 2 ; the self-corrosion current density of Test Sample 1 is 0.162 μA / cm 2 , and the corrosion inhibition efficiency is 88%; the self-corrosion current density of Test Sample 2 is 0.324 μA / cm 2 , and the corrosion inhibition efficiency is 77%. It can be seen that the a kind of rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves prepared in the above Example 15 has excellent rust inhibition effect on steel bars.
[0049] The laws of the two groups of experimental results are the same. It can be seen that adding 0.05% and 0.1% of the rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves to the simulated concrete pore solution significantly improves the corrosion resistance of steel bars and has excellent rust inhibition effect on steel bars.
[0050] The advantages of the present invention are as follows: Compared with traditional nitrite rust inhibitors, the rust inhibitor of the present invention is non-toxic, pollution-free, does not contain carcinogenic substances, and is more environmentally friendly. Solanum nigrum fruits are often used for medicinal development, and its stems and leaves are rich in resources but are often discarded. The present invention realizes the efficient development and low-cost utilization of resources by extracting the effective components of Solanum nigrum stems and leaves, and has significant ecological and economic benefits. The rust inhibitor of the present invention has a small dosage and low cost, can form a dense protective film on the surface of steel bars, and effectively inhibits the corrosion of steel bars. The rust inhibitor is directly incorporated into the concrete without complex treatment processes, has strong adaptability to concrete and does not affect its performance. Especially in structures such as coastal bridges where chloride ion erosion is severe, it shows excellent protection effects, can significantly enhance the durability of concrete structures, extend the service life and reduce the maintenance cost.
[0051] It should be understood that various forms of the processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the disclosure of the present invention can be executed in parallel, sequentially, or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is made herein.
[0052] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves, characterized in that: It includes the following components by mass parts: 20 - 40 parts of Solanum nigrum stem and leaf extract, 5 - 10 parts of potassium benzoate, 1 - 2 parts of magnesium oxide, and 20 - 50 parts of water.
2. The compound steel bar rust inhibitor of Solanum nigrum stems and leaves according to claim 1, characterized in that: The Solanum nigrum stem and leaf extract is 40 parts, the potassium benzoate is 5 parts, the magnesium oxide is 1 part, and the water is 40 parts.
3. A kind of rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves according to claim 1, characterized in that: The Solanum nigrum stem and leaf extract includes 2,5 - dihydroxybenzoic acid, 2-(3,4 - dihydroxyphenyl)-5,7 - dihydroxybenzofuran - 4 - one, 5,7 - dihydroxy - 2-(4 - hydroxyphenyl)benzofuran - 4 - one, 3,5,7 - trihydroxy - 2-(4 - hydroxyphenyl)benzofuran - 4 - one, and (E)-3-(3 - hydroxyphenyl)-2 - acrylic acid.
4. A composite steel bar rust inhibitor of Solanum nigrum stems and leaves according to any one of claims 1 to 3, characterized in that: The preparation method of the Solanum nigrum stem and leaf compound steel bar rust inhibitor is: weigh each component, stir and mix evenly at room temperature; The preparation method of the Solanum nigrum stem and leaf extract includes the following steps: S1: Select Solanum nigrum stems and leaves as raw materials, wash them with clean water, dry, crush, and sieve to obtain Solanum nigrum stem and leaf powder; S2: Add the Solanum nigrum stem and leaf powder into an ethanol solution, fully soak it at room temperature and then reflux extract; after extraction, perform vacuum filtration to collect the filtrate; S3: Concentrate the filtrate to obtain a concentrated solution; dry the concentrated solution to obtain the Solanum nigrum stem and leaf extract.
5. A kind of rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves according to claim 4, characterized in that: In step S2, the liquid - to - solid ratio of the Solanum nigrum stem and leaf powder to the ethanol solution is 15 - 20 mL:1 g.
6. A rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves according to claim 5, characterized in that: In step S2, the ethanol concentration in the ethanol solution is 65 - 75%; the time for fully soaking at room temperature is 40 - 60 min.
7. A kind of rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves according to claim 4, characterized in that: In step S2, the temperature for reflux extraction is 70 - 75 °C, the number of reflux extraction times is 3 - 4 times, and the extraction time for each time is 40 - 50 min.
8. A compound reinforcing steel bar rust inhibitor of Solanum nigrum stems and leaves according to claim 4, characterized in that: The drying in step S1 is specifically drying by baking, the baking temperature is 60 - 65 °C, and the time is 10 - 15 h; the sieving is through a 100 - mesh sieve.
9. A kind of rust inhibitor for steel bars compounded with Solanum nigrum stems and leaves according to claim 4, characterized in that: The drying in step S3 is specifically vacuum drying, the drying temperature is 60 - 65 °C, the vacuum degree is 300 Pa, and the drying time is 5 - 8 h.
10. Use of a Solanum nigrum L. stem and leaf compounded steel bar rust inhibitor according to any one of claims 1-9 in delaying steel bar corrosion, characterized in that: Mix the Solanum nigrum stem and leaf compound steel bar rust inhibitor into reinforced concrete, and the mixing amount accounts for 0.025 - 0.1% of the mass of the cementitious material in the reinforced concrete.