Modified nanolignin sulfonate corrosion inhibitor and preparation method and application thereof

Abstract

The present application relates to the technical field of corrosion inhibitor, especially to a modified nano-lignin sulfonate corrosion inhibitor and its preparation method and application, which comprises the following raw materials: lignin sulfonate, potassium persulfate, methacryloyloxyethyl trimethyl ammonium chloride and tetrahydrofuran; the mass ratio of lignin sulfonate, potassium persulfate and methacryloyloxyethyl trimethyl ammonium chloride is 0.1-1:0.01-0.05:0.3-3.The technical scheme provided by the present application grafts methacryloyloxyethyl trimethyl ammonium chloride onto nano-lignin sulfonate through polymerization reaction to synthesize modified nano-lignin sulfonate corrosion inhibitor, which has multiple nitrogen and oxygen adsorption sites, can provide lone pair of electrons to form coordination bond with iron atom, so that the corrosion inhibitor molecules can be better adsorbed on the metal surface to slow down the corrosion process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of corrosion inhibitors, in particular to a modified nanolignin sulfonate corrosion inhibitor and a preparation method and application thereof. BACKGROUND

[0002] Since the 20th century, the corrosion inhibitor corrosion protection method has been widely used in petrochemical, marine engineering and other industries due to its low cost, simple process and excellent corrosion protection effect.

[0003] Most of the reported lignin corrosion inhibitors use lignin, alkali lignin, lignin sulfate and the like as raw materials, but the synthesized corrosion inhibitors have poor corrosion inhibition effect and the preparation process is complex. The molecular structure of lignin sulfonate contains phenolic hydroxyl, alcoholic hydroxyl, sulfonic acid group, carboxyl group and the like, so it has good water solubility, adsorption, amphiphilic properties and the like. The modified lignin sulfonate has been widely used in water treatment agents, coal slurry dispersants, ion exchangers, water reducing agents, flocculants and the like. However, there are few reports on the use of lignin sulfonate as a corrosion inhibitor.

[0004] In view of the above problems, it is of great research significance and market value to develop a modified nanolignin sulfonate corrosion inhibitor with simple preparation process and excellent corrosion inhibition performance. SUMMARY

[0005] The first object of the present application is to provide a modified nanolignin sulfonate corrosion inhibitor with good corrosion inhibition effect. The second object of the present application is to provide a preparation method of the above-mentioned corrosion inhibitor, which is simple. The present application also provides the application of the above-mentioned corrosion inhibitor in preventing material corrosion.

[0006] The present application provides a modified nanolignin sulfonate corrosion inhibitor, which comprises the following raw materials: lignin sulfonate, potassium persulfate, methacryloxyethyl trimethyl ammonium chloride and tetrahydrofuran.

[0007] The mass ratio of the lignin sulfonate, the potassium persulfate and the methacryloxyethyl trimethyl ammonium chloride is 0.1-1:0.01-0.05:0.3-3; preferably, the mass-volume ratio of the lignin sulfonate and the tetrahydrofuran is 0.1-1 g:80-150 mL. The lignin sulfonate is slightly soluble in tetrahydrofuran. Tetrahydrofuran can act as a solvent to dissolve lignin sulfonate and as an activator to promote the bond breaking of lignin sulfonate.

[0008] The present application provides a preparation method of the above-mentioned modified nanolignin sulfonate corrosion inhibitor, which comprises the following steps:

[0009] (1) adding the lignin sulfonate into the tetrahydrofuran, stirring and dissolving, and then dialyzing,

[0010] (2) after dialysis is completed, the mixed solution of the potassium persulfate and the methylacryloyloxyethyl trimethyl ammonium chloride dissolved in water is added, and polymerization is carried out at a high temperature to obtain a polymer;

[0011] (3) the polymer obtained in step (2) is cooled to room temperature, ethanol is added for further polymerization, then vacuum filtration is carried out, semi-permeable membrane permeation is carried out, and then evaporation concentration, freezing drying are carried out at a high temperature to obtain the modified nanolignosulfonate corrosion inhibitor.

[0012] Preferably, the dialysis time in step (1) is 23.5-24.5 hours; more preferably, 24 hours.

[0013] Preferably, the volume of water added in step (2) and the mass of the lignosulfonate are in a ratio of 20-80 mL: 0.1-1 g.

[0014] Preferably, the temperature of the polymerization reaction in step (2) is 60-80℃, and the reaction time is 3-4 hours. The above polymerization reaction conditions can make the lignosulfonate fully converted into nanolignosulfonate in tetrahydrofuran, improve the yield, and also make the polymerization reaction fully proceed to the right, and the reaction is complete.

[0015] Preferably, the volume of ethanol added in step (3) and the mass of the lignosulfonate are in a ratio of 200-300 mL: 0.1-1 g.

[0016] Preferably, in step (3), the evaporation concentration is carried out by heating to 60-80℃.

[0017] Preferably, the semi-permeable membrane permeation time in step (3) is 2.8-3.2 hours, and the molecular cut-off of the semi-permeable membrane is 500 Da.

[0018] The obtained product is subjected to vacuum filtration, which aims to remove small particulate matters; and is subjected to dialysis in deionized water by using a semi-permeable membrane, which aims to purify soluble substances.

[0019] The above modified nanolignosulfonate corrosion inhibitor provided by the application is applied in preventing material corrosion.

[0020] Preferably, the material is carbon steel.

[0021] Compared with the prior art, the application has the following advantages:

[0022] (1) The technical scheme provided by the present application takes lignin sulfonate, potassium persulfate and methacryloxyethyl trimethyl ammonium chloride as raw materials, utilizes the characteristics of multiple hydroxyl and carboxyl functional groups on the nano lignin sulfonate molecules, grafts methacryloxyethyl trimethyl ammonium chloride onto the nano lignin sulfonate through a polymerization reaction, and synthesizes a modified nano lignin sulfonate corrosion inhibitor.

[0023] (2) Compared with the traditional lignin corrosion inhibitor, the modified nano lignin sulfonate corrosion inhibitor provided by the present application has more remarkable corrosion inhibition effect and can better inhibit the corrosion of metal.

[0024] (3) The preparation method of the modified nano lignin sulfonate corrosion inhibitor provided by the present application is simple in operation, the raw materials are easy to obtain, the synthesis time is relatively short, and the synthesis temperature is appropriate. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present application or the technical schemes in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0026] Figure 1 The Fourier transform infrared absorption spectrum of the modified nano lignin sulfonate corrosion inhibitor prepared in Example 2 of the present application;

[0027] Figure 2 The SEM image of the modified nano lignin sulfonate corrosion inhibitor prepared in Example 2 of the present application;

[0028] Figure 3 The three-electrode test system used in the present application;

[0029] Figure 4 The Nyquist plot of Q235 carbon steel immersed in 1mol / L HCl solution added with different concentrations of modified nano lignin sulfonate corrosion inhibitor for 1h in the test of the present application;

[0030] Figure 5 The polarization curve of Q235 carbon steel immersed in 1mol / L HCl solution added with different concentrations of modified nano lignin sulfonate corrosion inhibitor for 1h in the test of the present application;

[0031] Figure 6 The equivalent circuit diagram corresponding to the electrochemical impedance spectrum in the test of the present application. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0034] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited. In addition, the terms "mounting", "connecting", "connecting" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] Embodiment 1

[0036] A modified nanolignin sulfonate corrosion inhibitor comprises the following raw materials: lignin sulfonate 0.1 g, tetrahydrofuran 80 mL, potassium persulfate 0.01 g, and methacryloxyethyl trimethyl ammonium chloride 0.3 g.

[0037] The preparation method of the modified nanolignin sulfonate corrosion inhibitor is as follows:

[0038] (1) Dissolve the lignin sulfonate in tetrahydrofuran, stir and dissolve, and then dialyze for 24 h;

[0039] (2) dialysis is completed, potassium persulfate and methacryloyloxyethyl trimethyl ammonium chloride are dissolved in 20 mL of deionized water, and then warmed to 60℃, polymerization is carried out for 3 hours, to obtain a polymer;

[0040] (3) after the polymer obtained in step (2) is cooled to room temperature, 200 mL of ethanol is added for further polymerization, then vacuum suction filtration is carried out, semi-permeable membranes with a molecular weight cut-off of 500 Da are used for permeation for 3 hours, then heated to 60℃ for evaporation concentration, and freeze-drying is carried out, to obtain the modified nanolignin sulfonate corrosion inhibitor.

[0041] Example 2

[0042] A modified nanolignin sulfonate corrosion inhibitor comprises the following raw materials: 0.5 g of lignin sulfonate, 100 mL of tetrahydrofuran, 0.03 g of potassium persulfate, and 1.5 g of methacryloyloxyethyl trimethyl ammonium chloride.

[0043] The preparation method of the modified nanolignin sulfonate corrosion inhibitor is as follows:

[0044] (1) the lignin sulfonate is dissolved in tetrahydrofuran, and after stirring and dissolving, dialysis is carried out for 24 hours;

[0045] (2) after dialysis is completed, potassium persulfate and methacryloyloxyethyl trimethyl ammonium chloride are dissolved in 50 mL of deionized water, and then warmed to 70℃, polymerization is carried out for 4 hours, to obtain a polymer;

[0046] (3) after the polymer obtained in step (2) is cooled to room temperature, 250 mL of ethanol is added for further polymerization, then vacuum suction filtration is carried out, semi-permeable membranes with a molecular weight cut-off of 500 Da are used for permeation for 3 hours, then heated to 70℃ for evaporation concentration, and freeze-drying is carried out, to obtain the modified nanolignin sulfonate corrosion inhibitor.

[0047] Example 3

[0048] A modified nanolignin sulfonate corrosion inhibitor comprises the following raw materials: 1 g of lignin sulfonate, 150 mL of tetrahydrofuran, 0.05 g of potassium persulfate, and 3 g of methacryloyloxyethyl trimethyl ammonium chloride.

[0049] The preparation method of the modified nanolignin sulfonate corrosion inhibitor is as follows:

[0050] (1) the lignin sulfonate is dissolved in tetrahydrofuran, and after stirring and dissolving, dialysis is carried out for 24 hours;

[0051] (2) after dialysis is completed, potassium persulfate and methacryloyloxyethyl trimethyl ammonium chloride are dissolved in 80 mL of deionized water, and then warmed to 80℃, polymerization is carried out for 4 hours, to obtain a polymer;

[0052] (3) After cooling the polymer obtained in step (2) to room temperature, add 300 mL of ethanol for further polymerization, then perform vacuum filtration, use a semi-permeable membrane with a molecular cutoff of 500 Da for 3 h, then heat to 80 °C for evaporation and concentration, freeze dry to obtain modified nano lignin sulfonate corrosion inhibitor.

[0053] The modified nano-lignin sulfonate corrosion inhibitor sample prepared in Example 2 of this invention was analyzed by Fourier transform infrared absorption spectroscopy. Figure 1 As shown, at 3003cm -1 The absorption peaks at that point correspond to CH3 and N. + The stretching vibration, 1736cm -1 The absorption peak at 1456 cm⁻¹ corresponds to the stretching vibration of CO in the alkyl chain. -1 The absorption peak at the point indicates the characteristic vibration of C=N, indicating the successful synthesis of the modified nano-lignin sulfonate corrosion inhibitor.

[0054] The morphology of the modified nano-lignin sulfonate corrosion inhibitor sample prepared in Example 2 was further observed using SEM testing, such as... Figure 2 As shown, after dispersion and dilution with ethanol, the size of the nano-lignin sulfonate is 100 nm, which confirms the successful synthesis of the modified nano-lignin sulfonate.

[0055] The corrosion inhibition effect of the modified nano-lignin sulfonate corrosion inhibitor prepared in Example 2 was tested, and the test procedure is as follows:

[0056] Q235 carbon steel (10×10×2mm) was used, polished with 180, 400, 800, and 1200 grit SiC sandpaper, degreased with ethanol, and then dried with a hairdryer on a cool setting. One side (10×10mm) of the treated sample was retained, while the other five sides were sealed with high-temperature epoxy resin. The samples were then immersed in 1mol / L HCl solutions containing modified nano-lignin sulfonate corrosion inhibitors at concentrations of 0mg / L, 1mg / L, 2mg / L, 4mg / L, 8mg / L, and 15mg / L, respectively. After immersion for 1 hour, the electrochemical impedance spectroscopy (EIS) in the solution was measured. The soaking process is as follows: Prepare 6 portions of 200mL 1mol / L HCl solution, and add 0mg, 0.2mg, 0.4mg, 0.8mg, 1.6mg and 3mg of the modified nano-lignin sulfonate corrosion inhibitor prepared in Example 2 respectively to obtain soaking solutions with concentrations of 0mg / L, 1mg / L, 2mg / L, 4mg / L, 8mg / L and 15mg / L respectively. Soak each solution in a piece of Q235 carbon steel for 1 hour.

[0057] Using a three-electrode system, such as Figure 3The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum electrode. The electrochemical impedance is measured by a CS310H electrochemical workstation, with a frequency range of 10 4 -10 -2 Hz and an amplitude of 10 mV. The AC impedance spectra of Q235 carbon steel in 1 mol / L HCl solution with 0 mg / L, 1 mg / L, 2 mg / L, 4 mg / L, 8 mg / L, and 15 mg / L of modified nanolignin sulfonate corrosion inhibitor are shown in Figure 4 .

[0058] The data obtained by fitting the AC impedance spectra are shown in the equivalent circuit diagram in Figure 6 , and the corrosion inhibition efficiency is calculated, and the corrosion inhibition efficiency is calculated using the following formula:

[0059]

[0060] In the formula: η EIS is the corrosion inhibition efficiency, %; R 0 ct is the charge transfer resistance of the blank group, Ω·cm 2 ; R ct is the charge transfer resistance after adding the corrosion inhibitor, Ω·cm 2 .

[0061] The fitting results of the AC impedance spectra of Q235 carbon steel in 0 mg / L, 1 mg / L, 2 mg / L, 4 mg / L, 8 mg / L, and 15 mg / L of modified nanolignin sulfonate corrosion inhibitor are shown in Table 1.

[0062] Table 1 is the fitting results of the AC impedance spectra of Q235 carbon steel after immersion

[0063]

[0064] As shown in Table 1, after adding the modified nanolignin sulfonate corrosion inhibitor, the charge transfer resistance increased significantly, and when the concentration of the corrosion inhibitor was 15 mg / L, the corrosion inhibition efficiency reached 96.7%. The results show that in the 1 mol / L HCl solution environment, the addition of modified nanolignin sulfonate corrosion inhibitor has obvious corrosion inhibition effect on Q235 carbon steel.

[0065] The polarization curve of Q235 carbon steel in 1 mol / L HCl solution with different concentrations of modified nanolignin sulfonate corrosion inhibitor was measured according to the above test method, with a scanning range of ± 150 mV relative to the open circuit potential, a scanning rate of 0.5 mV / s, and a sampling frequency of 1 Hz. The polarization curve is shown in Figure 5 . The fitting results of the polarization curve are shown in Table 2, and the corrosion inhibition efficiency is calculated using the following formula:

[0066]

[0067] In the formula: η PDP is the corrosion efficiency, %; I θ O is the corrosion current of the blank control group after immersion for 1h, A / cm 2 ;I O is the corrosion current after adding the modified nanolignin sulfonate corrosion inhibitor and immersion for 1h, A / cm 2 .

[0068] Table 2 is the fitting result of the polarization curve of Q235 carbon steel after immersion

[0069]

[0070] As shown in Table 2, after adding the modified nanolignin sulfonate corrosion inhibitor, the corrosion current of Q235 carbon steel is reduced, which indicates that the modified nanolignin sulfonate corrosion inhibitor exhibits significant inhibition effect; when the concentration of the corrosion inhibitor is 15mg / L, the corrosion efficiency reaches 96.9%.

[0071] The modified nanolignin sulfonate corrosion inhibitor provided by the application is white colloid at normal temperature, and is easily soluble in water; the preparation method of the application is simple in operation, raw materials are easily obtained, the synthesis time is relatively short, and the synthesis temperature is appropriate.

[0072] In summary, the modified nanolignin sulfonate corrosion inhibitor provided by the application has stronger adsorption capacity, can better coordinate with the metal surface to form a dense adsorption protective layer, can better inhibit the corrosion of the metal, and has more significant corrosion inhibition effect.

[0073] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A method for preparing a modified nanolignosulfonate corrosion inhibitor, characterized in that, The lignosulfonate, the potassium persulfate and the methacryloyloxyethyl trimethyl ammonium chloride have a mass ratio of 0.1-1:0.01-0.05:0.3-3. The method comprises the following steps: (1) the lignosulfonate is added into the tetrahydrofuran, and after stirring and dissolving, dialysis is performed; (2) after the dialysis is completed, a mixed solution of the potassium persulfate and the methacryloyloxyethyl trimethyl ammonium chloride dissolved in water is added, and polymerization is performed under heating to obtain a polymer; (3) the polymer obtained in step (2) is cooled to room temperature, ethanol is added for further polymerization, then vacuum filtration is performed, semi-permeable membrane permeation is performed, and then evaporation concentration under heating, freeze drying are performed to obtain the modified nanometer lignosulfonate corrosion inhibitor.

2. The method of claim 1, wherein, The dialysis time in step (1) is 23.5-24.5 hours.

3. The method of claim 1, wherein the method further comprises, The volume of the water added in step (2) and the mass of the lignosulfonate have a ratio of 20-80 mL:0.1-1 g.

4. The method of claim 1, wherein the method further comprises, The temperature of the polymerization reaction in step (2) is 60-80 DEG C, and the reaction time is 3-4 hours.

5. The preparation method according to claim 1, characterized in that, The volume of the ethanol added in step (3) and the mass of the lignosulfonate have a ratio of 200-300 mL:0.1-1 g.

6. The method of claim 1, wherein the method further comprises, In step (3), evaporation concentration is performed under heating to 60-80 DEG C.

7. The method of claim 1, wherein the method further comprises, In step (3), the semi-permeable membrane permeation time is 2.8-3.2 hours, and the molecular cut-off of the semi-permeable membrane is 500 Da.

8. The modified nanometer lignosulfonate corrosion inhibitor prepared by the preparation method of claim 1 is applied to prevent material corrosion.

9. Use according to claim 8, characterized in that, The material is carbon steel.

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