阅读说明：本技术 一种利用豆类根瘤菌的钢筋阻锈剂及制备方法和应用 (Reinforcing steel bar rust inhibitor using legume rhizobium and preparation method and application thereof ) 是由 宋子健 蔡焕春 蒋林华 储洪强 张诗语 于 2021-11-08 设计创作，主要内容包括：本发明公开了一种利用豆类根瘤菌的钢筋阻锈剂及制备方法和应用。本发明所述的阻锈剂中包括豆类根瘤菌发酵物的有机溶剂浸取液。本发明利用豆类根瘤菌的钢筋阻锈剂原料为大豆收获后剩余的植株根茎,原料来源广泛且为废弃物,钢筋阻锈剂制备过程简单无毒,为环境节约友好型的绿色钢筋阻锈剂。(The invention discloses a reinforcing steel bar rust inhibitor utilizing legume rhizobium and a preparation method and application thereof. The rust inhibitor comprises an organic solvent leaching solution of a legume rhizobium fermentation product. The raw materials of the reinforcing steel bar rust inhibitor of the legume rhizobium are roots and stems of the residual soybean plants after harvesting, the raw materials are widely available and are wastes, the preparation process of the reinforcing steel bar rust inhibitor is simple and nontoxic, and the reinforcing steel bar rust inhibitor is an environment-friendly green reinforcing steel bar rust inhibitor.)

1. The reinforcing steel bar rust inhibitor utilizing the legume rhizobia is characterized by comprising an organic solvent leaching solution of legume rhizobia fermentation products.

2. The rebar rust inhibitor using legume rhizobia according to claim 1, wherein the legume rhizobia fermentation product is prepared by the following method:

(S11) adding 2000mL of nutritive gravy agar culture medium into the leguminous rhizobium, and culturing for 3-10 days at 50-60 ℃;

(S12) adding the product of the step (S11) to the ground soybean rhizome powder, and culturing at 50-60 ℃ for 10-50 days;

(S13) mixing the legume rhizobium powder prepared in the step (S12) with an organic solvent, stirring uniformly and standing;

(S14) adjusting the pH value of the mixed solution of the legume rhizobium powder prepared in the step (S13) and the organic solvent to 8.5-12 to obtain the reinforcing steel bar rust inhibitor.

3. A reinforcing bar rust inhibitor using legume rhizobium according to claim 1, wherein in step (S11), the nutrient broth agar medium contains 3.0g/L beef extract, 10.0g/L peptone, 5.0g/L NaCl and 15.0g/L agar.

4. A reinforcing bar rust inhibitor using legume rhizobium according to claim 1, wherein in step (S13), the legume rhizobium powder accounts for 5-20% by mass of the organic solvent.

5. The reinforcing bar rust inhibitor using legume rhizobium according to claim 1, wherein the mass of the product of the step (S1) in the step (S12) is 0.1-1% of the mass of the ground soybean rhizome powder.

6. A steel bar rust inhibitor using legume rhizobium according to claim 1, wherein in step (S11), the legume rhizobium is preferably sinorhizobium, magnolia benthamiana or acacia rhizobium.

7. The reinforcing bar rust inhibitor using legume rhizobium according to claim 1, wherein in the step (S11), 1-10mg of MnSO is added during the cultivation process₄。

8. The reinforcing bar rust inhibitor using legume rhizobium according to claim 1, wherein in the step (S13), the organic solvent is absolute ethyl alcohol.

9. The preparation method of the reinforcing steel bar rust inhibitor as claimed in claim 1, which is characterized by comprising the following steps:

(S21) adding 2000mL of nutritive gravy agar culture medium into the leguminous rhizobium, and culturing for 3-10 days at 50-60 ℃;

(S22) adding the product of the step (S21) to the ground soybean rhizome powder, and culturing at 50-60 ℃ for 10-50 days;

(S23) mixing the legume rhizobium powder prepared in the step (S22) with an organic solvent, stirring uniformly and standing;

(S24) adjusting the pH value of the mixed solution of the legume rhizobium powder prepared in the step (S23) and the organic solvent to 8.5-12 to obtain the reinforcing steel bar rust inhibitor.

10. Use of the rebar corrosion inhibitor of claim 1 to retard rebar corrosion; the application method is characterized in that the reinforcing steel bar rust inhibitor is doped into the reinforced concrete, and the doping amount accounts for 1-4% of the mass of the cement cementing material in the reinforced concrete.

Technical Field

The invention relates to the technical field of building materials, in particular to a reinforcing steel bar rust inhibitor produced by fermenting and culturing legume rhizobium by soybean plant roots and stems and an application method thereof.

Background

In the service environment rich in chlorine salt, the steel bar corrosion is the main cause of the corrosion damage of the reinforced concrete structure. The durability problem of the reinforced concrete structure caused by corrosion is very serious, the usability and the durability of the structure are influenced if the problem is serious, the bearing capacity of the structure is reduced if the problem is serious, and even the structure fails, so that huge economic loss is caused. The application of the rust inhibitor is one of the most effective measures for improving the durability of the reinforced concrete structure in actual engineering, but the rust inhibitor in the current market mainly comprises inorganic, organic or mixed chemical products, and has the problems of high cost, toxicity, great environmental pollution and the like. The rhizobium mainly refers to bacteria which are symbiotic with the roots of the bean crops to form rhizobia and can fix nitrogen, and nitrogen-containing organic matters in the rhizobium contain a large number of lone-pair electrons, so that the rhizobium has the potential of preparing the reinforcing steel bar rust inhibitor.

Disclosure of Invention

The purpose of the invention is as follows: the invention provides a reinforcing steel bar rust inhibitor utilizing legume rhizobium and a preparation method and application thereof. The steel bar rust inhibitor is prepared by extracting effective components of rhizobium fermentation products, has low cost and effectively improves the rust inhibiting capability of steel bars in concrete.

The technical scheme is as follows: the reinforcing steel bar rust inhibitor utilizing the legume rhizobia comprises an organic solvent leaching solution of a legume rhizobia fermentation product.

As a preferred embodiment of the present invention, the legume rhizobium fermented product is prepared by the following method:

(S11) adding 2000mL of nutritive gravy agar culture medium into the leguminous rhizobium, and culturing for 3-10 days at 50-60 ℃;

(S12) adding the product of the step (S11) to the ground soybean rhizome powder, and culturing at 50-60 ℃ for 10-50 days;

(S13) mixing the legume rhizobium powder prepared in the step (S12) with an organic solvent, stirring uniformly and standing;

(S14) adjusting the pH value of the mixed solution of the legume rhizobium powder prepared in the step (S13) and the organic solvent to 8.5-12 to obtain the reinforcing steel bar rust inhibitor.

As a preferred embodiment of the present invention, in the step (S11), the nutrient broth agar medium contains 3.0g/L beef extract, 10.0g/L peptone, 5.0g/L NaCl and 15.0g/L agar.

In a preferred embodiment of the present invention, in the step (S13), the legume rhizobium powder accounts for 5% to 20% by mass of the organic solvent.

In a preferred embodiment of the present invention, in the step (S12), the mass of the product of the step (S11) is 0.1% to 1% of the mass of the soybean rhizome mill flour.

In a preferred embodiment of the present invention, in the step (S11), the legume rhizobium is preferably sinorhizobium, magnolia benthamiana or acacia rhizobium.

As a preferred embodiment of the present invention, in the step (S11), 1-10mg of MnSO is added during the cultivation₄。

In a preferred embodiment of the present invention, in the step (S13), the organic solvent is absolute ethanol.

The preparation method of the reinforcing steel bar rust inhibitor comprises the following steps:

(S21) adding 2000mL of nutritive gravy agar culture medium into the leguminous rhizobium, and culturing for 3-10 days at 50-60 ℃;

(S22) adding the product of the step (S21) to the ground soybean rhizome powder, and culturing at 50-60 ℃ for 10-50 days;

(S23) mixing the legume rhizobium powder prepared in the step (S22) with an organic solvent, stirring uniformly and standing;

(S24) adjusting the pH value of the mixed solution of the legume rhizobium powder prepared in the step (S23) and the organic solvent to 8.5-12 to obtain the reinforcing steel bar rust inhibitor.

In a preferred embodiment of the present invention, the standing time in the step (S23) is 24 hours or more.

In a preferred embodiment of the present invention, the acid for adjusting the pH in the step (S24) is nitric acid or phosphoric acid, and the base is sodium hydroxide or potassium hydroxide.

The soybean rhizome grinding powder is soybean plant rhizome waste remained after the soybean is harvested, and is mechanically crushed into powder by a grinder after being naturally aired.

The reinforcing steel bar corrosion inhibitor is applied to delaying the corrosion of reinforcing steel bars.

The application method comprises the step of doping the reinforcing steel bar rust inhibitor into reinforced concrete, wherein the doping amount accounts for 1-4% of the mass of a cement cementing material in the reinforced concrete.

Has the advantages that: (1) the raw materials of the reinforcing steel bar rust inhibitor of the legume rhizobium are roots and stems of the residual plants after the soybeans are harvested, the raw materials are widely available and are waste, the preparation process of the reinforcing steel bar rust inhibitor is simple and non-toxic, and the reinforcing steel bar rust inhibitor is an environment-friendly green reinforcing steel bar rust inhibitor; (2) the rust inhibitor prepared by the invention has low cost and convenient use, can be directly added into concrete, effectively improves the rust inhibiting capability of steel bars in the concrete, and further prolongs the service life of a reinforced concrete structure.

Drawings

FIG. 1 shows Cl in a test environment^-Electrochemical impedance spectrums of the steel bar electrodes of the test sample 1, the test sample 2 and the control group at the concentration of 0.1 mol/L;

FIG. 2 shows the steel bar self-corrosion potential with Cl for the test sample 1, the test sample 2 and the control group^-Adding a concentration change trend graph;

FIG. 3 shows corrosion current densities of steel bars of test sample 1, test sample 2 and control group as a function of Cl^-Adding a concentration change trend graph.

Detailed Description

Example (b): the invention provides a reinforcing steel bar rust inhibitor prepared by fermenting and culturing legume rhizobia by soybean plant roots and stems. The soybean rhizome grinding powder in the embodiment is soybean plant rhizome waste left by harvested soybeans, and is naturally dried and mechanically crushed into powder by a grinder. The nutrient gravy agar medium in this example was prepared by the following method: taking 3.0g of beef extract, 10.0g of peptone, 5.0g of NaCl and 15.0g of agar, adding water to 1L, and heating to dissolve to obtain the nutrient broth agar medium. The steel bar rust inhibitor is prepared by the following method:

(1) taking a strain of legume rhizobium (Sinorhizobium 2 generation), using 1800mL of nutrient gravy agar, and adding 7mg of MnSO₄·H₂O, and culturing for 10 days at the temperature of 55 ℃;

(2) adding the product obtained in the step (1) into soybean rhizome grinding powder (mass ratio: 0.005: 1), and culturing at 55 ℃ for 40 days;

(3) mixing the legume rhizobium powder prepared in the step (2) with ethanol, wherein the mass ratio of the legume rhizobium powder to the ethanol is 15:100, uniformly stirring and standing for 24 hours;

s4: after filtering, the pH value is adjusted to 11.5 by phosphoric acid and sodium hydroxide solution, and the required steel bar rust inhibitor is obtained.

Adding the reinforcing steel bar rust inhibitor prepared by the method into a concrete simulation solution according to different addition amounts to prepare a test sample 1, a test sample 2 and a control group, testing the corrosion performance of the test sample 1, the test sample 2 and the control group, and further evaluating the rust inhibition performance of the rust inhibitor with different addition amounts on reinforcing steel bars, wherein the sample preparation comprises the following steps:

a. preparation of test sample 1

Cutting 12mm phi HPB235 steel bars into 5mm short steel bar bars, sealing the columnar side surfaces of the short steel bar bars with epoxy resin, taking the end surfaces as working surfaces, and gradually polishing the end surfaces to a mirror surface by using aluminum oxide metallographic abrasive paper; preparing saturated calcium hydroxide solution, and adjusting the pH value to 11.5 (the adjusting solution is phosphoric acid solution and sodium hydroxide solution); placing the steel bar ground into mirror polish into the saturated calcium hydroxide solution to prepare concrete simulation liquid; the reinforcing steel bar rust inhibitor prepared by the method and utilizing the legume rhizobium is added into a saturated calcium hydroxide solution of a concrete simulation solution according to 3 percent (volume percentage) to prepare a test sample 1, and the test sample 1 is sealed and subjected to corrosion performance test.

b. Preparation of test sample 2

Cutting 12mm phi HPB235 steel bars into 5mm short steel bar bars, sealing the columnar side surfaces of the short steel bar bars with epoxy resin, taking the end surfaces as working surfaces, and gradually polishing the end surfaces to a mirror surface by using aluminum oxide metallographic abrasive paper; preparing saturated calcium hydroxide solution, and adjusting the pH value to 11.5 by using phosphoric acid and sodium hydroxide solution; placing the steel bar ground into mirror polish into the saturated calcium hydroxide solution to prepare concrete simulation liquid; the reinforcing steel bar rust inhibitor prepared by the method and utilizing the legume rhizobium is added into a saturated calcium hydroxide solution of the concrete simulation solution according to 1 percent (volume percentage) to prepare a test sample 2, and the test sample 2 is sealed and subjected to corrosion performance test.

c. Preparation of control group

Cutting 12mm phi HPB235 steel bars into 5mm short steel bar bars, sealing the columnar side surfaces of the short steel bar bars with epoxy resin, taking the end surfaces as working surfaces, and gradually polishing the end surfaces to a mirror surface by using aluminum oxide metallographic abrasive paper; preparing saturated calcium hydroxide solution, and adjusting the pH value to 11.5 by using phosphoric acid and sodium hydroxide solution; placing the steel bar ground into mirror polish into the saturated calcium hydroxide solution to prepare concrete simulation liquid; the concrete simulation liquid is not added with the reinforcing steel bar rust inhibitor prepared by the method and utilizing the legume rhizobium, and the sample is used as a control group to carry out corrosion performance test in the same way.

By adopting a PARSTAT2273 electrochemical workstation, a typical three-electrode system (namely, a steel bar is used as a working electrode, a platinum electrode is used as an auxiliary electrode, and a saturated calomel electrode is used as a reference electrode) is adopted in a test system to test the electrochemical impedance spectrum, the self-corrosion potential and the corrosion current density of a test sample 1, a test sample 2 and a control group, and then the corrosion resistance of the steel bar by the corrosion inhibitor with different addition amounts is evaluated, wherein the specific test conditions are as follows:

(1) the electrochemical impedance spectrum is characterized in that an electrochemical system is applied with an alternating current potential wave with different frequencies and small amplitude, the change of the ratio of the alternating current potential to a current signal (the ratio is the impedance of the system) along with the frequency of a sine wave or the change of the phase angle of the impedance along with the frequency of the sine wave is measured, and then the mechanisms of electrode materials, solid electrolytes, conductive polymers, corrosion protection and the like are analyzed. In the experiment, the electrochemical impedance spectrum test adopts sinusoidal alternating voltage with disturbance amplitude of 10mV, the test frequency range is 10 mHz-100 KHz, and ZsimWin software is used for fitting and sorting the measured data.

The test results are shown in FIG. 1. Fig. 1 is a Nyquist diagram, which is a representation of electrochemical impedance spectroscopy, the impedance Z of an electrode is composed of a real part Z ' and an imaginary part Z ", i.e., Z ═ Z ' + j Z", the Nyquist diagram is plotted with the real part Z ' of the impedance as the abscissa and the imaginary part-Z "of the impedance as the ordinate, the larger the radius of the circular arc, i.e., the larger the polarization resistance, the better the corrosion resistance, and the smaller the radius of the circular arc, i.e., the smaller the polarization resistance, the worse the corrosion resistance.

The three curves in FIG. 1 represent Cl in the test environment^-When the concentration is 0.1mol/L, the electrochemical impedance spectrums of the steel bar electrodes of the test sample 1, the test sample 2 and the comparison group are the largest in curve radius of the test sample 1, the largest in polarization resistance of the steel bar and the best in corrosion resistance, the second in curve radius of the test sample 2 and the smallest in curve radius of the comparison group, and therefore, 3% and 1% (volume percentage) of the steel bar rust inhibitor utilizing the legume rhizobia is added into the concrete simulation liquid respectively, so that the corrosion resistance of the steel bar is obviously improved, and the steel bar rust inhibitor utilizing the legume rhizobia has a good rust inhibiting effect on the steel bar.

(2) The scanning potential of the potentiodynamic polarization curve test is-0.015V relative to the open circuit potential, and the scanning speed is 0.2 mV/s. Potentiodynamic testing was repeated at least three times per test condition in order to obtain better results.

The test results are shown in FIG. 2. The three curves in FIG. 2 represent the self-corrosion potential Ecorr of the steel bars of the test sample 1, the test sample 2 and the control group respectively with Cl^-Adding a concentration change trend graph, wherein the self-corrosion potential Ecorr is a parameter for thermodynamically characterizing the corrosion resistance trend of the material in a specific medium, and the larger the negative value of Ecorr is, the more easily corroded the steel bar is, as shown in figure 2, along with Cl^-The concentration is increased, the self-corrosion potential Ecorr of the steel bars of the test sample 1, the test sample 2 and the comparison group is in a trend of gradually decreasing, the self-corrosion potential Ecorr of the steel bars of the test sample 1 is reduced to the minimum compared with an initial value, the negative value of the self-corrosion potential Ecorr is the minimum, the negative value of the self-corrosion potential Ecorr of the steel bars of the test sample 2 is the second order, the negative value of the self-corrosion potential Ecorr of the steel bars of the comparison group is the maximum, the corrosion resistance of the steel bars of the test sample 1 is the strongest, and 3 percent (volume percentage) of the steel bars of the test sample 1 is 3 percent (volume percentage)Than ratio) of the reinforcing steel bar rust inhibitor by using the legume rhizobium^-The corrosion rate, 1% (volume percentage) of the steel bar rust inhibitor using leguminous rhizobium in the test sample 2 reduces the Cl content of the steel bar to a certain extent^-The rate of corrosion, the next time the corrosion resistance of the steel reinforcement of test sample 2, is the worst for the steel reinforcement of the control.

(3) The self-corrosion potential Ecorr was tested by Ecorr vs Time standard template in the PARSTAT2273 electrochemical workstation PowerCorr module.

The test results are shown in FIG. 3. The three curves in FIG. 3 represent the corrosion current densities i of the steel bars of test sample 1, test sample 2 and the control group, respectively_corrWith Cl^-The higher the corrosion current density icorr, the higher the corrosion rate of the steel bar, as shown in FIG. 3, with Cl^-The concentration is increased, the numerical value of the corrosion current density icorr of the steel bar of the test sample 1 is the minimum, and the numerical value is not obviously changed, which indicates that the corrosion rate of the steel bar of the test sample 1 is the lowest, the corrosion resistance of the steel bar is the strongest, and the corrosion rate of the steel bar is obviously reduced by 3 percent (volume percentage) of the steel bar rust inhibitor utilizing the legume rhizobium in the test sample 1; with Cl^-The numerical value of the steel bar corrosion current density icorr of the test sample 2 is increased due to the increase of the concentration, but the steel bar corrosion current density of the test sample 2 is still lower than that of the steel bar corrosion current density icorr of a control group, and therefore, the corrosion rate of the steel bar is reduced to a certain extent by the 1% (volume percentage) steel bar rust inhibitor utilizing the legume rhizobium in the test sample 2.