Corrosion inhibitor, corrosion inhibitor solution as well as preparation method and application of corrosion inhibitor solution

Abstract

The invention provides a corrosion inhibitor, a corrosion inhibitor solution and a preparation method and application thereof, and belongs to the technical field of metal corrosion inhibition. The corrosion inhibitor provided by the invention comprises a protein component and a polysaccharide component, the protein contains hydrophilic carboxyl, amino and hydrophobic groups, the polysaccharide contains hydrophilic hydroxyl and carboxyl, and the hydrophilic groups can be adsorbed on a stainless steel / solution interface, so that the activation energy of an interface reaction is increased, an interface double-electrode-layer structure is changed, and the corrosion inhibition effect is improved. The hydrophobic groups form a hydrophobic film on the surface of the stainless steel, so that transfer of substances or charges related to the corrosion reaction is prevented, the corrosion rate is slowed down, meanwhile, the hydrophobic groups can be adsorbed on the scaling surface, and crystal lattices of the scaling surface are distorted to generate soft scales, so that the corrosion resistance of the stainless steel is improved. The scale inhibitor is easy to wash away by water flow to achieve the scale inhibition effect.

Description

Technical Field

[0001] This invention belongs to the field of metal corrosion inhibition technology, specifically relating to a corrosion inhibitor, a corrosion inhibitor solution, its preparation method, and its application. Background Technology

[0002] Industrial cooling circulation systems are devices that control and maintain the temperature of equipment or processes by circulating cooling media, and are widely used in various industries. The pipes in industrial cooling circulation systems are primarily made of stainless steel. With increasing circulation frequency, the concentration of chloride, sulfate, and calcium ions in the industrial circulating cooling water increases, leading to pipe corrosion and scaling. To reduce corrosion and scaling, corrosion inhibitors are typically added to the industrial circulating cooling water. However, existing corrosion inhibitors are mainly phosphorus- and sulfur-containing organic corrosion inhibitors, which generally have limited corrosion inhibition effects and are prone to causing eutrophication of the water body, while also lacking scale inhibition capabilities. Summary of the Invention

[0003] The purpose of this invention is to provide a corrosion inhibitor, a corrosion inhibitor solution, a method for preparing the same, and its applications. The corrosion inhibitor provided by this invention does not contain phosphorus or sulfur, and simultaneously exhibits better corrosion inhibition and scale inhibition effects.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a corrosion inhibitor comprising a protein component and a polysaccharide component;

[0006] The protein composition, by weight percentage, comprises the following components: aspartic acid 6-7%, glutamic acid 7-8%, serine 4-5%, glycine 10-11%, histidine 0.5-1%, arginine 2-3%, threonine 3-4%, alanine 8-9%, proline 5-6%, tyrosine 3-4%, valine 9-10%, methionine 0.5-1%, cystine 0.05-0.1%, isoleucine 7-8%, leucine 10-11%, phenylalanine 4-5%, and lysine 14-15%.

[0007] The polysaccharide components, by mass percentage, include the following: mannose 4-5%, ribose 0.4-0.6%, rhamnose 6-7%, glucuronic acid 15-16%, galacturonic acid 1-2%, glucose 56.5-57.5%, galactose 4-5%, arabinose 8-9%, and fucose 0.1-0.5%.

[0008] The present invention also provides a corrosion inhibitor solution, comprising the corrosion inhibitor described in the above technical solution and water.

[0009] Preferably, the concentration of the corrosion inhibitor in the corrosion inhibitor solution is 0.3 to 0.7 g / L.

[0010] The present invention also provides a method for preparing the corrosion inhibitor or the corrosion inhibitor solution described in the above technical solution, comprising the following steps:

[0011] (1) Inoculate Enterobacter aegypti into a culture medium and culture to obtain Enterobacter aegypti bacterial solution;

[0012] (2) The Enterobacter aegyptiaceae bacterial solution obtained in step (1) is subjected to solid-liquid separation to obtain the supernatant;

[0013] (3) Dialyze the supernatant obtained in step (2) to obtain a corrosion inhibitor solution;

[0014] (4) The corrosion inhibitor solution obtained in step (3) is freeze-dried to obtain the corrosion inhibitor.

[0015] Preferably, the culture temperature in step (1) is 36-38°C and the culture time is 15-17 hours.

[0016] Preferably, the solid-liquid separation in step (2) includes: centrifuging the Enterobacter aegypti bacterial culture to obtain centrifuged liquid, and filtering the centrifuged liquid.

[0017] Preferably, the molecular weight cutoff of the dialysis bag during dialysis in step (3) is 3-4 kDa.

[0018] Preferably, the dialysis time in step (3) is 45 to 50 hours.

[0019] Preferably, the freeze-drying in step (4) includes a first freeze-drying, a second freeze-drying, and a third freeze-drying performed sequentially; the temperature of the first freeze-drying is -50 to -30°C, and the holding time of the first freeze-drying is 4 to 5 hours; the temperature of the second freeze-drying is -25 to -10°C, and the holding time of the second freeze-drying is 12 to 20 hours; the temperature of the third freeze-drying is 0 to 5°C, and the holding time of the third freeze-drying is 10 to 15 hours.

[0020] The present invention also provides the application of the corrosion inhibitor described in the above technical solution, or the corrosion inhibitor solution described in the above technical solution, or the corrosion inhibitor or corrosion inhibitor solution prepared by the preparation method described in the above technical solution, in inhibiting the corrosion of stainless steel.

[0021] This invention provides a corrosion inhibitor comprising a protein component and a polysaccharide component; the protein component, by mass percentage, comprises the following components: aspartic acid 6-7%, glutamic acid 7-8%, serine 4-5%, glycine 10-11%, histidine 0.5-1%, arginine 2-3%, threonine 3-4%, alanine 8-9%, proline 5-6%, tyrosine 3-4%, valine 9-10%, methionine 0.5-1%, and cysteine ​​0.0%. The polysaccharide composition comprises, by mass percentage, 5-0.1% mannose, 7-8% isoleucine, 10-11% leucine, 4-5% phenylalanine, and 14-15% lysine; and, by mass percentage, the polysaccharide composition comprises, 4-5% mannose, 0.4-0.6% ribose, 6-7% rhamnose, 15-16% glucuronic acid, 1-2% galacturonic acid, 56.5-57.5% glucose, 4-5% galactose, 8-9% arabinose, and 0.1-0.5% fucose. The corrosion inhibitor provided by this invention comprises protein and polysaccharide components. The protein contains hydrophilic carboxyl and amino groups, as well as hydrophobic groups, while the polysaccharide contains hydrophilic hydroxyl and carboxyl groups. The hydrophilic groups can adsorb at the stainless steel / solution interface, thereby increasing the activation energy of the interfacial reaction, altering the interfacial electric double layer structure, and thus inhibiting the cathodic or anodic reaction in the corrosion cell, leading to a reduction in the corrosion rate of stainless steel. The hydrophobic groups form a hydrophobic film on the stainless steel surface, preventing the transfer of substances or charges related to the corrosion reaction and slowing down the corrosion rate. Simultaneously, it can adsorb onto the scale surface, causing lattice distortion to form soft scale that is easily washed away by water, achieving a scale inhibition effect. The results of the embodiments show that the corrosion inhibitor provided by this invention has a corrosion inhibition efficiency of over 72% and a scale inhibition rate of over 90% for stainless steel. Detailed Implementation

[0022] This invention provides a corrosion inhibitor comprising a protein component and a polysaccharide component;

[0023] The protein composition, by weight percentage, comprises the following components: aspartic acid 6-7%, glutamic acid 7-8%, serine 4-5%, glycine 10-11%, histidine 0.5-1%, arginine 2-3%, threonine 3-4%, alanine 8-9%, proline 5-6%, tyrosine 3-4%, valine 9-10%, methionine 0.5-1%, cystine 0.05-0.1%, isoleucine 7-8%, leucine 10-11%, phenylalanine 4-5%, and lysine 14-15%.

[0024] The polysaccharide components, by mass percentage, include the following: mannose 4-5%, ribose 0.4-0.6%, rhamnose 6-7%, glucuronic acid 15-16%, galacturonic acid 1-2%, glucose 56.5-57.5%, galactose 4-5%, arabinose 8-9%, and fucose 0.1-0.5%.

[0025] The corrosion inhibitor provided by this invention includes a protein component.

[0026] The protein component in the corrosion inhibitor provided by this invention comprises 6-7% aspartic acid, based on mass percentage. As one embodiment, the mass percentage of aspartic acid may specifically be 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, or 7%.

[0027] The protein component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 7-8% glutamic acid. As one embodiment, the weight percentage of glutamic acid may specifically be 7%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, or 8%.

[0028] The protein component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 4-5% serine. As one embodiment, the weight percentage of serine may specifically be 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, or 5%.

[0029] The protein component in the corrosion inhibitor provided by this invention, based on mass percentage, further includes 10-11% glycine. As one embodiment, the mass percentage of glycine may specifically be 10%, 10.1%, 10.2%, 10.3%, 10.4%, 10.5%, 10.6%, 10.7%, 10.8%, 10.9%, or 11%.

[0030] The protein component in the corrosion inhibitor provided by this invention, based on mass percentage, further includes 0.5% to 1% histidine. As one embodiment, the mass percentage of histidine may specifically be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%.

[0031] The protein component of the corrosion inhibitor provided by this invention, by weight percentage, further includes 2-3% arginine. As one embodiment, the weight percentage of arginine may specifically be 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, or 3%.

[0032] The protein component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 3-4% threonine. As one embodiment, the weight percentage of threonine may specifically be 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4%.

[0033] The protein component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 8-9% alanine. As one embodiment, the weight percentage of alanine may specifically be 8%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, or 9%.

[0034] The protein component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 5-6% proline. As one embodiment, the weight percentage of proline may specifically be 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, or 6%.

[0035] The protein component of the corrosion inhibitor provided by this invention, by weight percentage, further includes 3-4% tyrosine. As one embodiment, the weight percentage of tyrosine may specifically be 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4%.

[0036] The protein component of the corrosion inhibitor provided by this invention, by weight percentage, further includes 9-10% valine. As one embodiment, the weight percentage of valine may specifically be 9%, 9.1%, 9.2%, 9.3%, 9.4%, 9.5%, 9.6%, 9.7%, 9.8%, 9.9%, or 10%.

[0037] The protein component in the corrosion inhibitor provided by this invention, based on mass percentage, further includes 0.5-1% methionine. As one embodiment, the mass percentage of methionine may specifically be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%.

[0038] The protein component in the corrosion inhibitor provided by this invention, based on a mass percentage, further includes 0.05-0.1% cystine. As one embodiment, the mass percentage of cystine may specifically be 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1%.

[0039] The protein component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 7-8% isoleucine. As one embodiment, the weight percentage of isoleucine may specifically be 7%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, or 8%.

[0040] The protein component in the corrosion inhibitor provided by this invention, based on mass percentage, further includes 10-11% leucine. As one embodiment, the mass percentage of leucine may specifically be 10%, 10.1%, 10.2%, 10.3%, 10.4%, 10.5%, 10.6%, 10.7%, 10.8%, 10.9%, or 11%.

[0041] The protein component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 4-5% phenylalanine. As one embodiment, the weight percentage of phenylalanine may specifically be 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, or 5%.

[0042] The protein component of the corrosion inhibitor provided by this invention, based on mass percentage, further includes 14-15% lysine. As one embodiment, the mass percentage of lysine may specifically be 14%, 14.1%, 14.2%, 14.3%, 14.4%, 14.5%, 14.6%, 14.7%, 14.8%, 14.9%, or 15%.

[0043] The corrosion inhibitor provided by this invention includes a polysaccharide component.

[0044] The polysaccharide component in the corrosion inhibitor provided by this invention comprises 4-5% mannose by weight percentage. As one embodiment, the mannose weight percentage may specifically be 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, or 5%.

[0045] The polysaccharide component in the corrosion inhibitor provided by this invention, based on a mass percentage, further includes 0.4% to 0.6% ribose. As one embodiment, the mass percentage of ribose may specifically be 0.4%, 0.42%, 0.44%, 0.46%, 0.48%, 0.5%, 0.52%, 0.54%, 0.56%, 0.58%, or 0.6%.

[0046] The polysaccharide component in the corrosion inhibitor provided by the present invention, by weight percentage, further includes 6-7% rhamnose. As one embodiment, the weight percentage of rhamnose may specifically be 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, or 7%.

[0047] The polysaccharide component in the corrosion inhibitor provided by this invention, based on a mass percentage, further includes 15-16% glucuronic acid. As one embodiment, the mass percentage of glucuronic acid may specifically be 15%, 15.1%, 15.2%, 15.3%, 15.4%, 15.5%, 15.6%, 15.7%, 15.8%, 15.9%, or 16%.

[0048] The polysaccharide component in the corrosion inhibitor provided by this invention, based on a mass percentage, further includes 1-2% galacturonic acid. As one embodiment, the mass percentage of galacturonic acid may specifically be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%.

[0049] The polysaccharide component in the corrosion inhibitor provided by this invention, based on mass percentage, further includes 56.5% to 57.5% glucose. As one embodiment, the mass percentage of glucose may specifically be 56.5%, 56.6%, 56.7%, 56.8%, 56.9%, 57%, 57.1%, 57.2%, 57.3%, 57.4%, or 57.5%.

[0050] The polysaccharide component in the corrosion inhibitor provided by the present invention, by weight percentage, further includes 4-5% galactose. As one embodiment, the weight percentage of galactose may specifically be 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, or 5%.

[0051] The polysaccharide component in the corrosion inhibitor provided by this invention, by weight percentage, further includes 8-9% arabinose. As one embodiment, the weight percentage of arabinose may specifically be 8%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, or 9%.

[0052] The polysaccharide component in the corrosion inhibitor provided by the present invention, based on a mass percentage, further includes 0.1% to 0.5% fucose. As one embodiment, the mass percentage of fucose may specifically be 0.1%, 0.2%, 0.3%, 0.4%, or 0.5%.

[0053] The corrosion inhibitor provided by this invention comprises protein and polysaccharide components. The protein contains hydrophilic carboxyl and amino groups as well as hydrophobic groups, while the polysaccharide contains hydrophilic functional groups, such as hydroxyl and carboxyl groups. The hydrophilic groups can adsorb at the stainless steel / solution interface, thereby increasing the activation energy of the interfacial reaction, changing the interfacial double layer structure, and thus inhibiting the cathodic or anodic reaction in the corrosion cell, leading to a reduction in the corrosion rate of stainless steel. The hydrophobic groups form a hydrophobic film on the stainless steel surface, preventing the transfer of substances or charges related to the corrosion reaction, reducing the surface roughness of stainless steel, slowing down the corrosion rate and the deposition of scale. At the same time, the corrosion inhibitor contains multiple carboxyl oxygen atoms, which can easily become adsorption sites for the corrosion inhibitor to interact with the metal crystal surface, thereby effectively preventing the continued growth of scale on the metal crystal surface. In addition, the protein and polysaccharide components cause the crystal lattice of the scale to be distorted, forming soft scale that is easily washed away by water flow, achieving the effect of scale inhibition.

[0054] The present invention also provides a corrosion inhibitor solution, comprising the corrosion inhibitor described in the above technical solution and water.

[0055] In this invention, the concentration of the corrosion inhibitor in the corrosion inhibitor solution is preferably 0.3–0.7 g / L. As one embodiment, the concentration of the corrosion inhibitor in the corrosion inhibitor solution can specifically be 0.3 g / L, 0.4 g / L, 0.5 g / L, 0.6 g / L, or 0.7 g / L. By controlling the concentration of the corrosion inhibitor in the corrosion inhibitor solution within the above range, this invention can further improve the corrosion inhibition and scale inhibition effects of the corrosion inhibitor solution.

[0056] The corrosion inhibitor provided by this invention can be used in solid form or in solution form, making it more convenient to use.

[0057] The present invention also provides a method for preparing the corrosion inhibitor or the corrosion inhibitor solution described in the above technical solution, comprising the following steps:

[0058] (1) Inoculate Enterobacter aegypti into a culture medium and culture to obtain Enterobacter aegypti bacterial solution;

[0059] (2) The Enterobacter aegyptiaceae bacterial solution obtained in step (1) is subjected to solid-liquid separation to obtain the supernatant;

[0060] (3) Dialyze the supernatant obtained in step (2) to obtain a corrosion inhibitor solution;

[0061] (4) The corrosion inhibitor solution obtained in step (3) is freeze-dried to obtain the corrosion inhibitor.

[0062] The present invention involves inoculating Enterobacter aegyptiaceae into a culture medium for cultivation to obtain Enterobacter aegyptiaceae bacterial suspension.

[0063] The present invention does not have any particular limitation on the source of the Enterobacter aegyptiacus, and products from commercially available products well known to those skilled in the art or products extracted by conventional extraction methods are acceptable.

[0064] As one implementation method, the extraction method of the Enterobacter aegyptiacus is as follows: (1) Select the bottom sludge of the cooling tower of a thermal power plant in Beijing as makeup water for the circulating cooling water system, let it stand and filter, take 10 mL of sludge water sample into 1 L Postgate C liquid medium (1 L Postgate C liquid medium contains 4.5 g Na2SO4, 1.0 g NH4Cl, 1.0 g yeast extract, 0.5 g KH2PO4, 0.3 g sodium citrate, 0.06 g CaCl2·6H2O, 0.06 g MgSO4·7H2O, 0.004 g FeSO4·7H2O, and the pH value of Postgate C liquid medium is 7.5±0.2), and then put it into a biochemical incubator at 37±1℃ for constant temperature anaerobic culture. After the liquid medium turns black, the enrichment solution is obtained.

[0065] (2) Prepare a nutrient-type Postgate C solid medium with an agar concentration of 2% (1L of Postgate C solid medium contains 4.5g Na2SO4, 1.0g NH4Cl, 1.0g yeast extract, 0.5g KH2PO4, 0.3g sodium citrate, 0.06g CaCl2·6H2O, 0.06g MgSO4·7H2O, 0.004g FeSO4·7H2O, 20g agar, and the pH of Postgate C solid medium is 7.5±0.2). After sterilization, wait until the temperature drops to 50℃, and under aseptic conditions, pour the medium into the lids of sterilized petri dishes, with a thickness of 1 / 4 of the height of the petri dish lid. After the culture medium plates (lower layer of medium) have cooled, divide the enrichment solution into 10... -2 10 -3 10 -4 After dilution (by volume), take 0.2 mL of the diluted solution and spread it evenly on a plate. Let it stand until the diluted solution seeps into the culture medium. Then, pour in Postgate C solid medium (top layer) of the same nutrient type, with a thickness of 2-3 mm. When pouring the top layer, make sure the liquid culture medium forms a convex shape. Immediately insert the inner plate of the culture dish bottom down and mouth and lid in the same direction into the top layer of culture medium to form a double-plate sample. Remove excess agar from the gap between the inner and outer plates and pour in melted sterile paraffin to evenly cover the entire gap around the culture dish with a layer of paraffin. Incubate at 28-30℃. After 5-6 days of incubation, many small black spherical colonies will grow on the plate. Select single colonies and repeat the dilution, spreading, double-plate incubation, and selection process twice to achieve the isolation and purification of the strain. The isolated and purified strain was identified as Enterobacter auriculi.

[0066] In this invention, the culture medium is preferably a liquid culture medium, more preferably Postgate C liquid culture medium; the 1L Postgate C liquid culture medium preferably contains 4-5g Na2SO4, 0.5-1.5g NH4Cl, 0.5-1.5g yeast extract, 0.1-1g KH2PO4, 0.1-0.5g sodium citrate, 0.05-0.1g CaCl2·6H2O, 0.05-0.1g MgSO4·7H2O, and 0.001-0.005g FeSO4·7H2O, more preferably containing 4.5g Na2SO4, 1.0g NH4Cl, 1.0g yeast extract, 0.5g KH2PO4, 0.3g sodium citrate, 0.06g CaCl2·6H2O, 0.06g MgSO4·7H2O, and 0.004g FeSO4·7H2O; the Postgate C liquid culture medium preferably contains ... The pH value of liquid culture medium C is preferably 7.5 ± 0.2.

[0067] In this invention, the volume ratio of Enterobacter alginate to culture medium is preferably 1:(10-25), more preferably 1:20.

[0068] In this invention, the culture temperature is preferably 36-38°C, more preferably 37°C; the culture time is preferably 15-17 hours, more preferably 16 hours.

[0069] After obtaining the Enterobacter aegyptiaceae bacterial solution, the present invention performs solid-liquid separation on the Enterobacter aegyptiaceae bacterial solution to obtain the supernatant.

[0070] In this invention, the solid-liquid separation preferably includes: centrifuging the Enterobacter aegypti bacterial culture to obtain a centrifuged liquid, and filtering the centrifuged liquid.

[0071] In this invention, the Enterobacter aeruginosa bacterial culture is preferably subjected to a first centrifugation to obtain a first solid and a first centrifuged liquid. The first centrifuged liquid is then mixed with phosphate buffered saline and subjected to a second centrifugation to obtain a centrifuged liquid, namely loose EPS.

[0072] After obtaining the first solid, the present invention preferably mixes the first solid with phosphate buffer brine and then performs a third centrifugation to obtain a bundled EPS.

[0073] In this invention, the first centrifugation rate is preferably 6000-7000 rpm, more preferably 6500 rpm; the first centrifugation time is preferably 4-6 min, more preferably 5 min.

[0074] In this invention, the phosphate buffer solution preferably comprises K₂HPO₄, KH₂PO₄, NaCl, and water; the concentration of K₂HPO₄ in the phosphate buffer solution is preferably 0.4–0.6 mmol / mL, more preferably 0.5 mmol / mL; the concentration of KH₂PO₄ in the phosphate buffer solution is preferably 0.4–0.6 mmol / mL, more preferably 0.5 mmol / mL; the concentration of NaCl in the phosphate buffer solution is preferably 0.01–0.02 mol / mL, more preferably 0.015 mol / mL; and the pH value of the phosphate buffer solution is preferably 6.5–7.5, more preferably 7.

[0075] In this invention, the volume ratio of the Enterobacter aeruginosa bacterial solution to phosphate-buffered saline is preferably (2-3):1, more preferably 2.5:1.

[0076] In this invention, the second centrifugation rate is preferably 6000-7000 rpm, more preferably 6500 rpm; the second centrifugation time is preferably 4-6 min, more preferably 5 min.

[0077] This invention controls the centrifugation parameters within the above-mentioned range, which can fully remove impurities from the bacterial solution.

[0078] In this invention, the filtration is preferably performed using a 0.22 μm microporous membrane. This invention does not impose any special limitations on the material or other parameters of the microporous membrane; any microporous membrane well-known to those skilled in the art can be used.

[0079] The present invention preferably preserves the supernatant at 3-5°C.

[0080] After obtaining the supernatant, the present invention dialyzes the supernatant to obtain a corrosion inhibitor solution.

[0081] In this invention, the molecular weight cutoff of the dialysis bag during dialysis is preferably 3-4 kDa, more preferably 3.5 kDa; the dialysis time is preferably 45-50 h, more preferably 48 h.

[0082] In this invention, the dialysis is preferably performed in deionized water; the deionized water is preferably replaced every 7 to 9 hours, more preferably every 8 hours.

[0083] In this invention, when the concentration of the corrosion inhibitor in the corrosion inhibitor solution is not within the desired range, water is preferably added to adjust the concentration of the corrosion inhibitor in the solution. This invention does not have a specific limitation on the amount of water used, as long as the concentration of the corrosion inhibitor in the solution is within the desired range.

[0084] The corrosion inhibitor solution is preferably stored at 3-5°C.

[0085] After obtaining the corrosion inhibitor solution, the present invention freeze-dries the corrosion inhibitor solution to obtain the corrosion inhibitor.

[0086] In this invention, the freeze-drying preferably includes a first freeze-drying, a second freeze-drying, and a third freeze-drying performed sequentially.

[0087] In this invention, the temperature of the first freeze-drying is preferably -50 to -30°C; the holding time of the first freeze-drying is preferably 4 to 5 hours; the temperature of the second freeze-drying is preferably -25 to -10°C, and the holding time of the second freeze-drying is preferably 12 to 20 hours; the temperature of the third freeze-drying is preferably 0 to 5°C, and the holding time of the third freeze-drying is preferably 10 to 15 hours.

[0088] The corrosion inhibitor prepared by this invention is a loose extracellular polymeric material with excellent corrosion inhibition and scale inhibition effects, and it is free of phosphorus and sulfur, making it green and environmentally friendly.

[0089] The present invention also provides the application of the corrosion inhibitor described in the above technical solution, or the corrosion inhibitor solution described in the above technical solution, or the corrosion inhibitor or corrosion inhibitor solution prepared by the preparation method described in the above technical solution, in inhibiting the corrosion of stainless steel.

[0090] In this invention, the corrosion inhibitor or corrosion inhibitor solution is preferably used to inhibit the corrosion of stainless steel in industrial cooling circulation devices, and more preferably to inhibit the corrosion of stainless steel in industrial circulating cooling water.

[0091] The present invention preferably involves adding a corrosion inhibitor or corrosion inhibitor solution to industrial circulating cooling water.

[0092] In one implementation, the industrial circulating cooling water is reclaimed water; the reclaimed water is obtained from a municipal wastewater treatment plant after secondary treatment.

[0093] In this invention, the concentration ratio of the industrial circulating cooling water is preferably 3 to 5 times, that is, the industrial circulating cooling water will evaporate and concentrate during the circulating cooling process. When the required concentration ratio is exceeded, the industrial circulating cooling water needs to be replaced.

[0094] In this invention, the volume ratio of the corrosion inhibitor solution to the industrial circulating cooling water is preferably 1:(10-50).

[0095] The present invention preferably adds a corrosion inhibitor or corrosion inhibitor solution every 15 to 30 days.

[0096] In this invention, the stainless steel material preferably includes SS304, SS316L or SS317L.

[0097] When the corrosion inhibitor or corrosion inhibitor solution provided by this invention is used to inhibit the corrosion of stainless steel, no additional alkali, complexing agent or other agents are required, no pH value adjustment is required, the operation is simple, the dosage is small, and it does not contain phosphorus and sulfur, so it will not cause secondary pollution such as eutrophication of water bodies, while having excellent corrosion inhibition and scale inhibition effects.

[0098] The corrosion inhibitor or corrosion inhibitor solution provided by this invention can effectively delay the corrosion of stainless steel pipes by industrial circulating cooling water. When the concentration ratio of industrial circulating cooling water is 3 to 5 times, the service life of stainless steel materials can be guaranteed to be ≥15 years, and up to 25 years.

[0099] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0100] The extraction method of Enterobacter aegyptiaceae in the example is as follows: (1) Select the bottom sludge of the cooling tower of a thermal power plant in Beijing as makeup water for the circulating cooling water system. After static filtration, take 10 mL of sludge water sample into 1 L Postgate C liquid medium (1 L Postgate C liquid medium contains 4.5 g Na2SO4, 1.0 g NH4Cl, 1.0 g yeast extract, 0.5 g KH2PO4, 0.3 g sodium citrate, 0.06 g CaCl2·6H2O, 0.06 g MgSO4·7H2O, 0.004 g FeSO4·7H2O, and the pH value of Postgate C liquid medium is 7.5±0.2). Then put it into a biochemical incubator at 37±1℃ for constant temperature anaerobic culture. After the liquid medium turns black, the enrichment solution is obtained.

[0101] (2) Prepare a nutrient-type Postgate C solid medium with an agar concentration of 2% (1L of Postgate C solid medium contains 4.5g Na2SO4, 1.0g NH4Cl, 1.0g yeast extract, 0.5g KH2PO4, 0.3g sodium citrate, 0.06g CaCl2·6H2O, 0.06g MgSO4·7H2O, 0.004g FeSO4·7H2O, 20g agar, and the pH of Postgate C solid medium is 7.5±0.2). After sterilization, wait until the temperature drops to 50℃, and under aseptic conditions, pour the medium into the lids of sterilized petri dishes, with a thickness of 1 / 4 of the height of the petri dish lid. After the culture medium plates (lower layer of medium) have cooled, divide the enrichment solution into 10... -2 10 -3 10 -4After dilution (by volume), 0.2 mL of the diluted solution was evenly spread on a plate and allowed to stand until it seeped into the culture medium. Then, a 3 mm thick layer of Postgate C solid medium (top layer) was poured in, creating a convex shape. The inner dish was then inserted bottom-down, with the opening and lid aligned, forming a double-plate sample. Excess agar was removed from the gap between the inner and outer dishes, and melted sterile paraffin was poured in, ensuring a uniform paraffin layer around the entire dish. The plate was incubated at 29±1℃. After 5 days of incubation, numerous small black spherical colonies grew on the plate. Single colony selection was performed, and the process of dilution, spreading, double-plate incubation, and selection was repeated twice to achieve the isolation and purification of the strain. The isolated and purified strain was identified as Enterobacter auriculi.

[0102] The water quality parameters of the reclaimed water in each application example are: pH value 7.31; conductivity 750 μS·cm. -1 The total hardness is 244.8 mg CaCO3L. -1 Cl - The content is 108.1 mg·L. -1 SO4 2- The content is 177.0 mg·L. -1 NO3 - The content is 97.7 mg·L. -1 ;PO4 3- The content is 1.14 mg·L. -1 NH4 + The content is 1.69 mg·L. -1 COD Cr It is 55.7 mg·L -1 The BOD5 content was 44.5 mg·L⁻¹. -1 Turbidity was 1.89 NTU; K + The content is 27.6 mg·L. -1 Na + The content is 82.4 mg·L. -1 ;Ca 2+ The content is 175.61 mg·L. -1 ;Mg 2+ The content is 65.52 mg·L. -1 Fe 3+ The content is 0.17 mg·L. -1 Al 3+ The content is 0.58 mg·L. -1 ;Si 2+ The content is 24.36 mg·L. -1 Mn 2+ The content is 0.17 mg·L. -1Zn 2+ The content is 3.43 mg·L. -1 The total bacterial count was 6.25 × 10⁻⁶. 7 L -1 .

[0103] Example 1

[0104] A corrosion inhibitor solution, composed of a corrosion inhibitor and water.

[0105] The corrosion inhibitor is composed of protein and polysaccharide components;

[0106] The protein composition, by weight percentage, comprises the following components: aspartic acid 6.91%, glutamic acid 7.84%, serine 4.21%, glycine 10.38%, histidine 0.85%, arginine 2.06%, threonine 3.45%, alanine 8.06%, proline 5.72%, tyrosine 3.95%, valine 9.50%, methionine 0.83%, cystine 0.06%, isoleucine 7.05%, leucine 10.38%, phenylalanine 4.41%, and lysine 14.34%.

[0107] The polysaccharide component, by mass percentage, consists of the following components: mannose 4.51%, ribose 0.5%, rhamnose 6.72%, glucuronic acid 15.46%, galacturonic acid 1.73%, glucose 57%, galactose 4.77%, arabinose 8.92%, and fucose 0.39%.

[0108] The concentration of the corrosion inhibitor in the corrosion inhibitor solution is 0.3 g / L;

[0109] The method for preparing the corrosion inhibitor solution is as follows: (1) 10 mL of Enterobacter aegypti is inoculated into 200 mL of Postgate C liquid medium (1 L of Postgate C liquid medium contains 4.5 g of Na2SO4, 1.0 g of NH4Cl, 1.0 g of yeast extract, 0.5 g of KH2PO4, 0.3 g of sodium citrate, 0.06 g of CaCl2·6H2O, 0.06 g of MgSO4·7H2O, 0.004 g of FeSO4·7H2O, and the pH value of Postgate C liquid medium is 7.5±0.2), and cultured at 37℃ for 16 h to obtain Enterobacter aegypti bacterial solution;

[0110] (2) Take 25 mL of the Enterobacter aegypti bacterial culture obtained in step (1) and centrifuge at 6500 rpm for 5 min to obtain the first centrifuge liquid. Then mix it with 10 mL of phosphate buffered saline. The phosphate buffered saline is composed of K2HPO4, KH2PO4, NaCl and water. The concentration of K2HPO4 is 0.5 mmol / mL, the concentration of KH2PO4 is 0.5 mmol / mL, the concentration of NaCl is 0.015 mol / mL, and the pH value is 7. Centrifuge at 6500 rpm for 5 min to obtain the centrifuge liquid. Filter the centrifuge liquid through a 0.22 μm microporous filter membrane to obtain the supernatant.

[0111] (3) Transfer the supernatant obtained in step (2) to a 3.5 kDa dialysis bag and dialyze in deionized water for 48 hours. Replace the deionized water every 8 hours. Mix the dialyzed solution with water to obtain a corrosion inhibitor solution.

[0112] Application Example 1

[0113] The reclaimed water was concentrated at 40°C in a constant temperature water bath, and the chloride ion concentration was measured. Concentration was stopped when the chloride ion concentration was three times that of the reclaimed water, and the resulting 3-fold concentrated reclaimed water was filtered through a 0.22μm microporous membrane to obtain experimental water (stored at 4°C).

[0114] SS304, SS316L, and SS317L stainless steel were processed into square test pieces of 10mm*10mm*1mm. Copper wires were soldered to one side of the test piece, and the other side was polished with sandpaper and diamond abrasive paste to serve as the working interface. The test piece was placed in a PVC pipe and sealed and insulated with epoxy resin to obtain a stainless steel electrode. The SS304, SS316L, and SS317L stainless steel test pieces were then successively ground, polished, soaked in acetone for 10 minutes, soaked in anhydrous ethanol for 10 minutes, and dried to obtain stainless steel test pieces. The stainless steel test pieces and stainless steel electrodes were irradiated under a UV lamp for 30 minutes and then immersed in three times the volume of concentrated regenerated water by rotating the plate. The corrosion inhibitor solution from Example 1 was added, with a volume ratio of corrosion inhibitor solution to three times the volume of concentrated regenerated water of 1:50. The reaction was carried out at 25±1℃ and stirred at 2000rpm for 24 hours.

[0115] After the reaction was completed, the stainless steel test piece and stainless steel electrode were removed. The corrosion inhibition efficiency of the corrosion inhibitor solution of Example 1 on the stainless steel test piece was obtained by weight loss method, electrochemical AC impedance spectroscopy, and polarization curve testing. The scale inhibition rate was tested by calcium ion, magnesium ion, alkalinity, and chloride ion concentrations. The corrosion inhibition efficiency of the corrosion inhibitor solution of Example 1 on the stainless steel test piece after 24 hours was 72%, and the scale inhibition rate was 90% (the corrosion inhibition efficiency and scale inhibition rate of the three types of stainless steel test pieces can achieve the above effects, the same below).

[0116] Application Example 2

[0117] In Application Example 1, the volume ratio of the corrosion inhibitor solution to 3 times concentrated regenerated water was replaced with 1:30, while all other parameters remained the same as in Application Example 1. In Application Example 2, the corrosion inhibitor solution achieved a corrosion inhibition efficiency of 75% and a scale inhibition rate of 92% on the stainless steel specimen after 24 hours.

[0118] Example 2

[0119] The concentration of the corrosion inhibitor in the corrosion inhibitor solution of Example 1 was replaced with 0.4 g / L, and all other parameters were the same as in Example 1.

[0120] Example 3

[0121] The concentration of the corrosion inhibitor in the corrosion inhibitor solution of Example 1 was replaced with 0.5 g / L, and all other parameters were the same as in Example 1.

[0122] Application Example 3

[0123] The corrosion inhibitor solution in Example 1 of Application Example 2 was replaced with the corrosion inhibitor solution in Example 3. All other parameters were the same as in Application Example 2. The corrosion inhibition efficiency of the corrosion inhibitor solution in Application Example 3 on the stainless steel specimen after 24 hours was 80%, and the scale inhibition rate was 96%.

[0124] Application Example 4

[0125] The reaction time in Application Example 3 was replaced with 3 days, while all other parameters remained the same as in Application Example 3. The test results showed that the corrosion inhibition efficiency of the corrosion inhibitor solution on the stainless steel specimen in Application Example 4 was 85% and the scale inhibition rate was 97% after 3 days.

[0126] Application Example 5

[0127] The 3-fold concentrated regenerated water in Application Example 4 was replaced with 4-fold concentrated regenerated water, and all other parameters were the same as in Application Example 4. The corrosion inhibition efficiency of the corrosion inhibitor solution on the stainless steel specimen in Application Example 5 was 81% and the scale inhibition rate was 94% after 3 days.

[0128] Application Example 6

[0129] The 3-fold concentrated regenerated water in Application Example 4 was replaced with 5-fold concentrated regenerated water, and all other parameters were the same as in Application Example 4. The corrosion inhibition efficiency of the corrosion inhibitor solution on the stainless steel specimen in Application Example 6 was 76% and the scale inhibition rate was 91% after 3 days.

[0130] Application Example 7

[0131] The reaction time in Application Example 3 was replaced with 15 days, while all other parameters remained the same as in Application Example 3. The test results showed that the corrosion inhibitor solution in Application Example 7 had a corrosion inhibition efficiency of 80% and a scale inhibition rate of 93% on the stainless steel specimen after 15 days.

[0132] Comparative Application Example 1

[0133] The Enterobacter aegypti in Example 3 was replaced with ATCC 7757 strain, and all other parameters were the same as in Example 3. A corrosion inhibitor solution was obtained, and then tested according to the method in Application Example 4. The test results showed that the corrosion efficiency of the corrosion inhibitor solution in Application Example 1 on the stainless steel specimen for 3 days was 30-35% higher than that in Application Example 4, and the scale inhibition rate was 80%.

[0134] Comparative Application Example 2

[0135] The corrosion inhibitor solution in Example 3 was replaced with a tight-packed EPS solution. The difference between the preparation method of the corrosion inhibitor solution and that in Example 1 is as follows: (2) 25 mL of the Enterobacter aegypti bacterial solution obtained in step (1) was centrifuged at 6500 rpm for 5 min to obtain the first solid. Then, it was mixed with 10 mL of phosphate buffered saline, which consisted of K2HPO4, KH2PO4, NaCl and water. The concentration of K2HPO4 was 0.5 mmol / mL, the concentration of KH2PO4 was 0.5 mmol / mL, the concentration of NaCl was 0.015 mol / mL, and the pH value was 7. The mixture was then centrifuged at 6500 rpm for 5 min to obtain the centrifuged liquid. The centrifuged liquid was filtered through a 0.22 μm microporous filter membrane to obtain the supernatant. All other parameters were the same as in Example 3. The test was performed according to the method in Application Example 4. The corrosion inhibition efficiency of the stainless steel test piece in Application Example 2 for 3 days was 62%, and the scale inhibition rate was 83%.

[0136] In summary, the corrosion inhibitor or corrosion inhibitor solution provided by this invention has excellent corrosion inhibition and scale inhibition effects on stainless steel.

[0137] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A corrosion inhibitor comprising a protein component and a polysaccharide component; The protein composition, by weight percentage, comprises the following components: aspartic acid 6-7%, glutamic acid 7-8%, serine 4-5%, glycine 10-11%, histidine 0.5-1%, arginine 2-3%, threonine 3-4%, alanine 8-9%, proline 5-6%, tyrosine 3-4%, valine 9-10%, methionine 0.5-1%, cystine 0.05-0.1%, isoleucine 7-8%, leucine 10-11%, phenylalanine 4-5%, and lysine 14-15%. The polysaccharide components, by mass percentage, include the following: mannose 4-5%, ribose 0.4-0.6%, rhamnose 6-7%, glucuronic acid 15-16%, galacturonic acid 1-2%, glucose 56.5-57.5%, galactose 4-5%, arabinose 8-9%, and fucose 0.1-0.5%.

2. A corrosion inhibitor solution comprising the corrosion inhibitor of claim 1 and water.

3. The corrosion inhibitor solution according to claim 2, characterized in that, The concentration of the corrosion inhibitor in the corrosion inhibitor solution is 0.3–0.7 g / L.

4. A method for preparing the corrosion inhibitor of claim 1 or the corrosion inhibitor solution of claim 2 or 3, comprising the following steps: (1) Inoculate Enterobacter aegypti into a culture medium and culture to obtain Enterobacter aegypti bacterial solution; (2) The Enterobacter aegyptiaceae bacterial solution obtained in step (1) is subjected to solid-liquid separation to obtain the supernatant; (3) Dialyze the supernatant obtained in step (2) to obtain a corrosion inhibitor solution; (4) The corrosion inhibitor solution obtained in step (3) is freeze-dried to obtain the corrosion inhibitor.

5. The preparation method according to claim 4, characterized in that, The culture temperature in step (1) is 36-38℃, and the culture time is 15-17h.

6. The preparation method according to claim 4, characterized in that, The solid-liquid separation in step (2) includes: centrifuging the Enterobacter aegypti bacterial solution to obtain centrifuged liquid, and filtering the centrifuged liquid.

7. The preparation method according to claim 4, characterized in that, In step (3), the molecular weight cutoff of the dialysis bag during dialysis is 3-4 kDa.

8. The preparation method according to claim 4 or 7, characterized in that, The dialysis time in step (3) is 45-50 hours.

9. The preparation method according to claim 4, characterized in that, The freeze-drying in step (4) includes a first freeze-drying, a second freeze-drying, and a third freeze-drying performed sequentially; the temperature of the first freeze-drying is -50 to -30°C, and the holding time of the first freeze-drying is 4 to 5 hours; the temperature of the second freeze-drying is -25 to -10°C, and the holding time of the second freeze-drying is 12 to 20 hours; the temperature of the third freeze-drying is 0 to 5°C, and the holding time of the third freeze-drying is 10 to 15 hours.

10. The application of the corrosion inhibitor of claim 1, or the corrosion inhibitor solution of claim 2 or 3, or the corrosion inhibitor or corrosion inhibitor solution prepared by any one of claims 4 to 9 in inhibiting the corrosion of stainless steel.