Graphene enhanced efficient degreasing agent and preparation method thereof

Abstract

The invention relates to the technical field of chemical engineering and processes, in particular to a graphene enhanced efficient degreasing agent and a preparation method thereof.The graphene enhanced efficient degreasing agent comprises a component A and a component B. The component A is prepared from, by weight, 1-3 parts of reduced graphene oxide, 3-8 parts of nano iron powder and 1-4 parts of a cationic surface active agent; the component B comprises the following components in parts by weight: 2-5 parts of sulfonated activated carbon and 0.5-2 parts of modified sodium silicate; wherein the weight ratio of the component A to the component B is (1-2): 1, the reduced graphene oxide and the nano iron powder are innovatively introduced to form a synergistic effect with a traditional surfactant, the degreasing efficiency is improved by 40-50% compared with that of a traditional degreasing agent, and the degreasing time is shortened by 40-60%.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical engineering and technology. Specifically, it relates to a graphene-enhanced high-efficiency degreaser and its preparation method, which is particularly suitable for degreasing treatment and anti-oxidation protection of metal surfaces. The present invention also relates to the fields of surfactant technology and fine chemical engineering, and can be widely applied to the metal surface pretreatment processes in industries such as machining, automobile manufacturing, electronic components, and aerospace. Background Art

[0002] With the development of modern industry, the surface treatment technology of metal parts has become increasingly important. Before painting, electroplating or other subsequent processing on the metal surface, it is necessary to thoroughly remove the oil, fat and other contaminants on the surface, otherwise it will seriously affect the quality and lifespan of the subsequent processes. Traditional metal surface degreasing processes mainly include methods such as organic solvent degreasing, alkaline aqueous solution degreasing, emulsifier degreasing and surfactant degreasing. Although these methods can remove the oil on the metal surface to a certain extent, they generally have problems such as low degreasing efficiency, long processing time, large environmental pollution, and poor anti-oxidation performance, and it is difficult to meet the requirements of modern industry for efficient, environmentally friendly and multifunctional surface treatment.

[0003] In recent years, with the development of nanomaterial science, graphene, as a new type of two-dimensional carbon nanomaterial, has begun to be applied in various fields. For example, US Patent US9399580B2 discloses graphene oxide particles prepared by a spray drying method, which have a three-dimensional wrinkled morphology and good electrical conductivity characteristics. However, this patent mainly focuses on the preparation method of graphene materials itself and does not involve its application in degreasers.

[0004] Chinese Patent CN110453232B discloses a phosphorus-free normal-temperature composite metal surface degreaser, which discloses a metal surface degreasing composition containing surfactants, alkaline components and chelating agents, but does not involve the application of nanomaterials, and there is still great room for improvement in degreasing efficiency and processing time.

[0005] Chinese Patent CN108704389B discloses a graphene-modified activated carbon composite filter element and its preparation method and application, which contains 0.1%-10% of graphene and 90-99.9% of modified activated carbon. Although this patent composites graphene with activated carbon, it is mainly used in the field of water treatment filtration and is not for metal surface degreasing and anti-oxidation applications.

[0006] In the prior art, there has been no report on effectively combining graphene, nano iron powder with traditional surfactants, activated carbon, sodium silicate and other components to form a degreaser with dual functions of high-efficiency degreasing and anti-oxidation. In particular, in the prior art, there is a lack of a degreaser technical solution that adopts an A / B two-component design, scientifically proportioning functional materials such as graphene, nano iron powder, activated carbon and sodium silicate, and using ultrasonic dispersion and precise temperature control processes to achieve high-efficiency degreasing and form a long-lasting anti-oxidation film. Summary of the Invention

[0007] The main object of the present invention is to provide a graphene-enhanced high-efficiency degreaser and its preparation method. The degreaser innovatively combines functional materials such as graphene, nano iron powder, and activated carbon, adopts an A / B two-component design, solves technical problems such as low degreasing efficiency, long treatment time, and poor anti-oxidation performance in the prior art, and realizes high-efficiency degreasing and long-lasting anti-oxidation protection of the metal surface.

[0008] To achieve the above object, the present invention provides a graphene-enhanced high-efficiency degreaser, including component A and component B. The degreaser is composed of the following components in parts by weight: Component A: 1-3 parts by weight of reduced graphene oxide, 3-8 parts by weight of nano iron powder, 1-4 parts by weight of cationic surfactant; Component B: 2-5 parts by weight of sulfonated activated carbon, 0.5-2 parts by weight of modified sodium silicate; wherein, the weight ratio of component A to component B is 1-2:1.

[0009] The reduced graphene oxide of the present invention has a particle size range of 300-500 mesh, a sheet thickness of 1-10 nm, a specific surface area of 300-700 m 2 / g, an oxygen content of 5-15%, and a C / O ratio controlled at 6-10. The reduced graphene oxide within this specific parameter range not only maintains good conductivity but also has sufficient functional groups to ensure dispersion stability in the aqueous phase.

[0010] The nano iron powder of the present invention is zero-valent iron powder with a core-shell structure, the core particle size is 20-100 nm, the surface is coated with an ultrathin iron oxide shell layer (Fe / Fe3O4), and the specific surface area is 15-35 m 2 / g. The nano iron powder with this special structure not only maintains high activity but also has sufficient stability, can form a synergistic effect with graphene, and significantly improves the degreasing efficiency.

[0011] The cationic surfactant of the present invention is benzalkonium chloride, with a concentration of 30-35 wt% aqueous solution and an HLB value of 18-22. This surfactant has excellent graphene dispersion stability, and at the same time has strong electrolyte characteristics, can form a positively charged stable colloid system, and has good wettability and oil emulsification ability for the metal surface.

[0012] The sulfonated activated carbon of the present invention is mesoporous activated carbon modified with sodium dodecylbenzenesulfonate, with a particle size of 5 - 20 μm, a specific surface area of 800 - 1200 m 2 / g, the mesoporous pore diameter is mainly distributed in 2 - 20 nm, and the sulfonic acid group content is 0.8 - 1.2 mmol / g. This modified activated carbon has better hydrophilicity and adsorption capacity, and can efficiently adsorb oil stains and organic pollutants on the metal surface.

[0013] The modified sodium silicate of the present invention is sodium silicate modified with aluminum ions and polyethylene glycol, with a concentration of 35 - 40 wt% aqueous solution and a modulus (SiO2 / Na2O molar ratio) of 3.0 - 3.5. This modified sodium silicate has good film-forming properties and can form a uniform and dense protective film on the metal surface to provide long-term anti-oxidation protection.

[0014] The present invention also provides a preparation method of the graphene-enhanced high-efficiency degreasing agent, including the following steps:

[0015] (1) Preparation of component A;

[0016] (2) Preparation of component B;

[0017] (3) Mix the component A and the component B according to a weight ratio of 1 - 2:1 before use.

[0018] Among them, the preparation of component A in step (1) includes: First, add 700 - 750 parts by weight of deionized water to a reaction vessel; Second, add 1 - 4 parts by weight of the cationic surfactant under stirring conditions and stir for 10 - 15 minutes to form a solution; Then, add 1 - 3 parts by weight of the reduced graphene oxide and perform ultrasonic dispersion treatment for 30 minutes; Again, slowly add 3 - 8 parts by weight of the nano iron powder under gentle stirring conditions, continue to stir for 15 - 20 minutes after the feeding is completed, and perform ultrasonic treatment for 10 - 15 minutes; Finally, add 0.5 - 1.0 part by weight of sodium citrate as a stabilizer, adjust the pH value to 6.5 - 7.5, age at 50 ± 2 °C for 2 - 4 hours, and cool to room temperature to obtain the component A.

[0019] The preparation of component B in step (2) includes: First, dilute the commercial sodium silicate solution to 25 - 30 wt%, add aluminum sulfate solution and 0.5 - 1.0 wt% polyethylene glycol for modification, stir evenly, and age for 12 - 24 hours to obtain 0.5 - 2 parts by weight of the modified sodium silicate; Second, add 400 - 450 parts by weight of deionized water and 0.5 - 1.0 part by weight of non-ionic surfactant in another reaction vessel; Then, add 2 - 5 parts by weight of the sulfonated activated carbon under stirring conditions and stir for 30 - 45 minutes; Third, slowly add the modified sodium silicate solution under gentle stirring conditions, and control the mass ratio of the solid content of activated carbon to sodium silicate to be 3:1 to 4:1; Finally, after stirring evenly, cure at 60 ± 2 °C for 2 - 4 hours, cool to room temperature to obtain component B.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1) The degreasing efficiency is significantly improved: By innovatively introducing reduced graphene oxide and nano iron powder, a synergistic effect is formed with traditional surfactants. The degreasing efficiency is increased by 40 - 50% compared with traditional degreasing agents, and the degreasing time is shortened by 40 - 60%.

[0022] 2) Excellent anti-oxidation performance: The degreasing agent of the present invention can form a graphene-containing silicate protective film on the metal surface, significantly improving the anti-oxidation performance of the metal surface, and the protection time can reach 3 - 6 months.

[0023] 3) A / B two-component design: The present invention adopts an A / B two-component design, effectively solving the compatibility problem between components such as graphene and activated carbon, extending the shelf life of the product, and improving the convenience of use.

[0024] 4) Environmentally friendly: The present invention adopts a water-based formulation, does not contain organic solvents, phosphates and heavy metals, meeting the requirements of modern industry for environmentally friendly degreasing agents.

[0025] 5) Wide applicability: The degreasing agent of the present invention is applicable to the surface treatment of various metal materials such as steel, aluminum alloy, and copper alloy, and has broad application prospects in the fields of machining, automobile manufacturing, electronic appliances, aerospace, etc. Specific embodiments

[0026] The following further illustrates the present invention with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0027] The main raw materials used in the present invention and their sources are as follows:

[0028] 1. Reduced graphene oxide (rGO), specification: particle size range 300 - 500 mesh, sheet thickness 1 - 10 nm, specific surface area 300 - 700 m 2 / g, with an oxygen content of 5 - 15%, and a C / O ratio of 6 - 10.

[0029] Preparation method: Graphene oxide is prepared by the improved Hummers method and then partially reduced by a chemical reduction method:

[0030] (1) Add 5 g of graphite powder to a mixed solution composed of 120 ml of concentrated sulfuric acid and 2.5 g of sodium nitrate, and stir for 30 minutes under an ice bath condition;

[0031] (2) Slowly add 15 g of potassium permanganate under stirring conditions, and control the reaction temperature not to exceed 20 °C;

[0032] (3) Stir the mixture at 35 °C for 6 hours, then add 150 ml of deionized water and continue stirring for 2 hours;

[0033] (4) Add 30 ml of 30% hydrogen peroxide solution to terminate the reaction, generating a yellowish-brown solution;

[0034] (5) Filter, and wash with dilute hydrochloric acid and deionized water until the pH value is 6 - 7 to obtain graphene oxide;

[0035] (6) Disperse the graphene oxide in water, add an appropriate amount of ascorbic acid (vitamin C) as a reducing agent, and react at 95 °C for 2 hours;

[0036] (7) Filter, wash, and vacuum dry at 80 °C for 24 hours to obtain partially reduced graphene oxide.

[0037] 2. Nano zero-valent iron powder (NZVI), trade name: S-MicroZVI, supplier: REGENESIS (USA) or the Ferox Flow product series of Hepure Technologies, specification: core particle size 20 - 100 nm, surface coated with an ultrathin iron oxide shell layer (Fe / Fe3O4), specific surface area 15 - 35 m 2 / g, purity ≥ 99.5%.

[0038] The nano iron powder is prepared by a liquid phase reduction method:

[0039] (1) Under the protection of an inert gas, dissolve 10 g of ferrous sulfate heptahydrate (FeSO4·7H2O) in 100 ml of deionized water;

[0040] (2) Slowly dropwise add 30 ml of an aqueous solution containing 4 g of sodium borohydride (NaBH4), and control the temperature at 20 - 25 °C;

[0041] (3) After the reaction is completed, separate the black nano iron powder with a magnet and wash it 3 times with deionized water and ethanol respectively;

[0042] (4) Under the protection of inert gas, disperse nano iron powder in 0.05M sodium citrate solution and stir for 1 hour for surface passivation;

[0043] (5) Filter, wash with ethanol, and vacuum dry at 50 °C for 6 hours to obtain nano iron powder with a core-shell structure.

[0044] 3. Cationic surfactant, chemical name: benzalkonium chloride; specification: 30-35wt% aqueous solution, HLB value 18-22, pH value (1% aqueous solution) is 6.0-8.0

[0045] 4. Sulfonated activated carbon, which is modified using standard activated carbon

[0046] Preparation method:

[0047] (1) Immerse activated carbon in 0.5-2.0% sodium dodecylbenzenesulfonate aqueous solution, with a liquid-solid ratio of 10:1 (ml / g);

[0048] (2) Control the temperature at 60 ± 5 °C and react for 4-6 hours, with sufficient stirring;

[0049] (3) Filter, wash with deionized water until neutral;

[0050] (4) Dry at 80 ± 5 °C for 12-24 hours;

[0051] (5) Grind to a particle size of 5-20 μm to obtain sulfonated activated carbon.

[0052] 5. Modified sodium silicate, which is modified using a commercial sodium silicate solution (such as the N series of PQ Corporation)

[0053] Preparation method:

[0054] (1) Dilute the commercial sodium silicate solution (40wt%) to 25-30wt%;

[0055] (2) Slowly add 1-2wt% aluminum sulfate solution (Al2(SO4)3·18H2O) for modification and stir evenly;

[0056] (3) Add 0.5-1.0wt% polyethylene glycol (PEG1000) for further modification;

[0057] (4) Stir evenly and age at room temperature for 12-24 hours to obtain modified sodium silicate.

[0058] Example 1

[0059] A graphene-enhanced high-efficiency degreaser, including component A and component B, and the degreaser is composed of the following components in parts by weight:

[0060] Component A: 1 part by weight of reduced graphene oxide, 3 parts by weight of nano iron powder, 1 part by weight of cationic surfactant;

[0061] Component B: 2 parts by weight of sulfonated activated carbon, 0.5 part by weight of modified sodium silicate;

[0062] Among them, the weight ratio of Component A to Component B is 1:1.

[0063] The particle size range of the reduced graphene oxide is 300 mesh, the sheet thickness is 1 nm, the specific surface area is 300 m 2 / g, the oxygen content is 5%, and the C / O ratio is 10.

[0064] The nano iron powder is zero-valent iron powder with a core-shell structure, the core particle size is 20 nm, the surface is coated with an ultrathin iron oxide shell layer (Fe / Fe3O4), and the specific surface area is 15 m 2 / g.

[0065] The cationic surfactant is benzalkonium chloride, with a concentration of 30 wt% aqueous solution and an HLB value of 18.

[0066] The sulfonated activated carbon is mesoporous activated carbon modified by sodium dodecylbenzenesulfonate, with a particle size of 5 μm, a specific surface area of 800 m 2 / g, the mesoporous pore diameter is mainly distributed at 2 nm, and the sulfonic acid group content is 0.8 mmol / g.

[0067] The modified sodium silicate is sodium silicate double-modified by aluminum ions and polyethylene glycol, with a concentration of 35 wt% aqueous solution and a modulus (SiO2 / Na2O molar ratio) of 3.0.

[0068] The preparation method of this graphene-enhanced high-efficiency degreasing agent includes the following steps:

[0069] (1) Preparation of Component A:

[0070] First, add 700 parts by weight of deionized water to a 1000 ml reaction vessel;

[0071] Secondly, add 1 part by weight of the cationic surfactant under stirring conditions (300 rpm) and stir for 10 minutes to form a solution;

[0072] Then, add 1 part by weight of the reduced graphene oxide and perform ultrasonic dispersion treatment for 30 minutes. Specifically, use an ultrasonic probe with a power of 300 W to perform high-power (80% output power) pulse mode (3 seconds on / 2 seconds off) treatment for the initial 5 minutes, and then perform subsequent 25-minute medium-power (50% output power) continuous mode treatment. During the treatment process, keep the temperature of the dispersion system at 25°C;

[0073] Next, 3 parts by weight of the nano iron powder is slowly added under gentle stirring conditions (200 rpm), the feeding rate is controlled at 3 g / min, and after the feeding is completed, stirring is continued for 15 minutes, and ultrasonic treatment is carried out for 10 minutes (power is 200 W, continuous mode);

[0074] Finally, 0.5 part by weight of sodium citrate is added as a stabilizer, the pH value is adjusted to 6.5, aged at 50 °C for 2 hours, and cooled to room temperature to obtain the component A.

[0075] (2) Preparation of component B:

[0076] First, the commercial sodium silicate solution (40 wt%) is diluted to 25 wt%, aluminum sulfate solution (Al2(SO4)3·18H2O, 1 wt%) is added for modification, 0.5 wt% of polyethylene glycol (PEG1000) is added, stirred evenly, and aged for 12 hours to obtain 0.5 part by weight of the modified sodium silicate;

[0077] Secondly, 400 parts by weight of deionized water is added to a 600 ml reaction vessel, and 0.5 part by weight of a non-ionic surfactant (polyoxyethylene ether) is added;

[0078] Then, 2 parts by weight of the sulfonated activated carbon is added under stirring conditions (300 rpm), and stirred for 30 minutes;

[0079] Next, the modified sodium silicate solution is slowly added under gentle stirring conditions (150 rpm), and the mass ratio of the solid content of activated carbon to sodium silicate is controlled at 4:1;

[0080] Finally, after stirring evenly, it is cured at 60 °C for 2 hours and cooled to room temperature to obtain the component B.

[0081] (3) Before use, the component A and the component B are mixed according to a weight ratio of 1:1.

[0082] The sulfonated activated carbon is prepared by soaking activated carbon in a 0.5% aqueous solution of sodium dodecylbenzenesulfonate, with a liquid-solid ratio of 10:1 (ml / g), a temperature of 60 °C, and a time of 4 hours. After that, it is filtered, washed with deionized water until neutral, and dried at 80 °C for 12 hours, and ground to a particle size of 5 μm to obtain the sulfonated activated carbon.

[0083] The graphene-enhanced high-efficiency degreaser of this example is suitable for degreasing and anti-oxidation treatment of the surface of galvanized steel sheets. The use concentration is 10% of the original concentration, the treatment temperature is 25 °C, and the action time is 10 minutes. The experimental results show that the degreasing efficiency of this degreaser on the surface of galvanized steel sheets is 40% higher than that of traditional alkaline degreasers, and the formed anti-oxidation film can provide a 3-month protection period.

[0084] Example 2

[0085] A graphene-enhanced high-efficiency degreaser, comprising component A and component B, and the degreaser is composed of the following components in parts by weight:

[0086] Component A: 2 parts by weight of reduced graphene oxide, 5 parts by weight of nano iron powder, 2 parts by weight of cationic surfactant;

[0087] Component B: 3 parts by weight of sulfonated activated carbon, 1 part by weight of modified sodium silicate;

[0088] Wherein, the weight ratio of component A to component B is 1.5:1.

[0089] The particle size range of the reduced graphene oxide is 400 mesh, the sheet thickness is 5 nm, the specific surface area is 500 m 2 / g, the oxygen content is 10%, and the C / O ratio is 8.

[0090] The nano iron powder is zero-valent iron powder with a core-shell structure, the core particle size is 50 nm, the surface is coated with an ultrathin iron oxide shell layer (Fe / Fe3O4), and the specific surface area is 25 m 2 / g.

[0091] The cationic surfactant is benzalkonium chloride, with a concentration of 32 wt% aqueous solution and an HLB value of 20.

[0092] The sulfonated activated carbon is mesoporous activated carbon modified by sodium dodecylbenzenesulfonate, with a particle size of 10 μm, a specific surface area of 1000 m 2 / g, the mesoporous pore diameter is mainly distributed at 10 nm, and the sulfonic acid group content is 1.0 mmol / g.

[0093] The modified sodium silicate is sodium silicate double-modified by aluminum ions and polyethylene glycol, with a concentration of 37 wt% aqueous solution and a modulus (SiO2 / Na2O molar ratio) of 3.2.

[0094] The preparation method of the graphene-enhanced high-efficiency degreaser comprises the following steps:

[0095] (1) Preparation of component A:

[0096] First, add 725 parts by weight of deionized water to a 1000 ml reaction vessel;

[0097] Secondly, add 2 parts by weight of the cationic surfactant under stirring conditions (350 rpm) and stir for 12 minutes to form a solution;

[0098] Then, 2 parts by weight of the reduced graphene oxide is added, and ultrasonic dispersion treatment is carried out for 30 minutes. Specifically, it is carried out as follows: an ultrasonic probe with a power of 350 W is used for high-power (85% output power) pulse mode (3 seconds on / 2 seconds off) treatment for the initial 5 minutes, and then subsequent 25 minutes of medium-power (55% output power) continuous mode treatment. During the treatment process, the temperature of the dispersion system is maintained at 30 °C;

[0099] Again, under gentle stirring conditions (225 rpm), 5 parts by weight of the nano iron powder is slowly added, and the feeding rate is controlled at 4 g / min. After the feeding is completed, stirring is continued for 17 minutes, and ultrasonic treatment is carried out for 12 minutes (power is 225 W, continuous mode);

[0100] Finally, 0.7 part by weight of sodium citrate is added as a stabilizer, the pH value is adjusted to 7.0, and it is aged at 50 °C for 3 hours, and then cooled to room temperature to obtain the component A.

[0101] (2) Preparation of component B:

[0102] First, the commercial sodium silicate solution (40 wt%) is diluted to 27 wt%, aluminum sulfate solution (Al2(SO4)3·18H2O, 1.5 wt%) is added for modification, 0.7 wt% of polyethylene glycol (PEG1000) is added, and it is stirred evenly and aged for 18 hours to obtain 1 part by weight of the modified sodium silicate;

[0103] Secondly, 425 parts by weight of deionized water is added to a 600 ml reaction vessel, and 0.7 part by weight of a non-ionic surfactant (polyoxyethylene ether type) is added;

[0104] Then, under stirring conditions (350 rpm), 3 parts by weight of the sulfonated activated carbon is added and stirred for 37 minutes;

[0105] Again, under gentle stirring conditions (175 rpm), the modified sodium silicate solution is slowly added, and the mass ratio of the solid content of activated carbon to sodium silicate is controlled at 3.5:1;

[0106] Finally, after stirring evenly, it is cured at 60 °C for 3 hours and cooled to room temperature to obtain the component B.

[0107] (3) Before use, the component A and the component B are mixed according to a weight ratio of 1.5:1.

[0108] The sulfonated activated carbon is prepared by soaking activated carbon in a 1.0% aqueous solution of sodium dodecylbenzenesulfonate, with a liquid-solid ratio of 10:1 (ml / g), a temperature of 62 °C, and a time of 5 hours. Then, it is filtered, washed with deionized water until neutral, and dried at 80 °C for 18 hours, and ground to a particle size of 10 μm to obtain the sulfonated activated carbon.

[0109] The graphene-enhanced high-efficiency degreaser of this embodiment is applicable to the degreasing and anti-oxidation treatment of the aluminum alloy surface. The use concentration is 20% of the original concentration, the treatment temperature is 30 °C, and the action time is 8 minutes. The experimental results show that the degreasing efficiency of this degreaser on the aluminum alloy surface is 45% higher than that of the traditional acidic degreaser, and the formed anti-oxidation film can provide a protection period of 4 months.

[0110] Example 3

[0111] A graphene-enhanced high-efficiency degreaser, comprising component A and component B, and the degreaser is composed of the following components in parts by weight:

[0112] Component A: 3 parts by weight of reduced graphene oxide, 8 parts by weight of nano iron powder, 4 parts by weight of cationic surfactant;

[0113] Component B: 5 parts by weight of sulfonated activated carbon, 2 parts by weight of modified sodium silicate;

[0114] Among them, the weight ratio of component A to component B is 2:1.

[0115] The particle size range of the reduced graphene oxide is 500 mesh, the sheet thickness is 10 nm, the specific surface area is 700 m 2 / g, the oxygen content is 15%, and the C / O ratio is 6.

[0116] The nano iron powder is zero-valent iron powder with a core-shell structure, the core particle size is 100 nm, the surface is coated with an ultra-thin iron oxide shell layer (Fe / Fe3O4), and the specific surface area is 35 m 2 / g.

[0117] The cationic surfactant is benzalkonium chloride, the concentration is 35 wt% aqueous solution, and the HLB value is 22.

[0118] The sulfonated activated carbon is mesoporous activated carbon modified by sodium dodecylbenzenesulfonate, the particle size is 20 μm, the specific surface area is 1200 m 2 / g, the mesoporous pore diameter is mainly distributed at 20 nm, and the sulfonic acid group content is 1.2 mmol / g.

[0119] The modified sodium silicate is sodium silicate double-modified by aluminum ions and polyethylene glycol, the concentration is 40 wt% aqueous solution, and the modulus (SiO2 / Na2O molar ratio) is 3.5.

[0120] The preparation method of this graphene-enhanced high-efficiency degreaser includes the following steps:

[0121] (1) Preparation of component A:

[0122] First, add 750 parts by weight of deionized water to a 1000 ml reaction vessel;

[0123] Secondly, add 4 parts by weight of the cationic surfactant under stirring conditions (400 rpm) and stir for 15 minutes to form a solution;

[0124] Then, add 3 parts by weight of the reduced graphene oxide and perform ultrasonic dispersion treatment for 30 minutes. Specifically, perform high-power (90% output power) pulse mode (3 seconds on / 2 seconds off) treatment with an ultrasonic probe at a power of 400 W for the initial 5 minutes, and then perform subsequent medium-power (60% output power) continuous mode treatment for 25 minutes. During the treatment process, keep the temperature of the dispersion system at 35 °C;

[0125] Again, slowly add 8 parts by weight of the nano iron powder under gentle stirring conditions (250 rpm), control the feeding rate at 5 g / min, continue stirring for 20 minutes after the feeding is completed, and perform ultrasonic treatment for 15 minutes (power is 250 W, continuous mode);

[0126] Finally, add 1.0 part by weight of sodium citrate as a stabilizer, adjust the pH value to 7.5, age at 52 °C for 4 hours, and cool to room temperature to obtain the component A.

[0127] (2) Preparation of component B:

[0128] First, dilute the commercial sodium silicate solution (40 wt%) to 30 wt%, add aluminum sulfate solution (Al2(SO4)3·18H2O, 2 wt%) for modification, add 1.0 wt% of polyethylene glycol (PEG1000), stir evenly, and age for 24 hours to obtain 2 parts by weight of the modified sodium silicate;

[0129] Secondly, add 450 parts by weight of deionized water and 1.0 part by weight of a non-ionic surfactant (polyoxyethylene ether type) to a 600 ml reaction vessel;

[0130] Then, add 5 parts by weight of the sulfonated activated carbon under stirring conditions (400 rpm) and stir for 45 minutes;

[0131] Again, slowly add the modified sodium silicate solution under gentle stirring conditions (200 rpm), and control the mass ratio of the solid content of activated carbon to sodium silicate to be 3:1;

[0132] Finally, after stirring evenly, cure at 62 °C for 4 hours and cool to room temperature to obtain the component B.

[0133] (3) Before use, mix the component A and the component B according to a weight ratio of 2:1.

[0134] The preparation of the sulfonated activated carbon is carried out by soaking activated carbon in an aqueous solution of 2.0% sodium dodecylbenzenesulfonate with a liquid-solid ratio of 10:1 (ml / g), a temperature of 65 °C, and a time of 6 hours. Then, it is filtered, washed with deionized water until neutral, dried at 80 °C for 24 hours, and ground to a particle size of 20 μm to obtain the sulfonated activated carbon.

[0135] The graphene-enhanced high-efficiency degreaser of this example is applicable to the degreasing and anti-oxidation treatment of the copper alloy surface. The use concentration is 30% of the original concentration, the treatment temperature is 35 °C, and the action time is 5 minutes. The experimental results show that the degreasing efficiency of this degreaser for the copper alloy surface is 50% higher than that of the traditional organic solvent degreaser, and the formed anti-oxidation film can provide a protection period of 6 months.

[0136] Example 4

[0137] A graphene-enhanced high-efficiency degreaser, including component A and component B, and the degreaser is composed of the following components in parts by weight:

[0138] Component A: 1.5 parts by weight of reduced graphene oxide, 4 parts by weight of nano iron powder, 2 parts by weight of cationic surfactant;

[0139] Component B: 2.5 parts by weight of sulfonated activated carbon, 1 part by weight of modified sodium silicate;

[0140] Among them, the weight ratio of component A to component B is 1.2:1.

[0141] The particle size range of the reduced graphene oxide is 350 mesh, the sheet thickness is 3 nm, the specific surface area is 400 m 2 / g, the oxygen content is 8%, and the C / O ratio is 9.

[0142] The nano iron powder is zero-valent iron powder with a core-shell structure, the core particle size is 35 nm, the surface is coated with an ultrathin iron oxide shell layer (Fe / Fe3O4), and the specific surface area is 20 m 2 / g.

[0143] The cationic surfactant is benzalkonium chloride, with a concentration of 31 wt% aqueous solution and an HLB value of 19.

[0144] The sulfonated activated carbon is mesoporous activated carbon modified by sodium dodecylbenzenesulfonate, with a particle size of 8 μm, a specific surface area of 900 m 2 / g, the mesoporous pore diameter is mainly distributed at 5 nm, and the sulfonic acid group content is 0.9 mmol / g.

[0145] The modified sodium silicate is sodium silicate double-modified by aluminum ions and polyethylene glycol, with a concentration of 36 wt% aqueous solution and a modulus (SiO2 / Na2O molar ratio) of 3.1.

[0146] The preparation method of the graphene-enhanced high-efficiency degreasing agent comprises the following steps:

[0147] (1) Preparation of component A:

[0148] First, add 715 parts by weight of deionized water to a 1000 ml reaction vessel;

[0149] Second, add 2 parts by weight of the cationic surfactant under stirring conditions (325 rpm) and stir for 12 minutes to form a solution;

[0150] Then, add 1.5 parts by weight of the reduced graphene oxide, and perform ultrasonic dispersion treatment for 30 minutes. Specifically, perform high-power (82% output power) pulse mode (3 seconds on / 2 seconds off) treatment for the initial 5 minutes with an ultrasonic probe of 325 W power, and then perform subsequent medium-power (53% output power) continuous mode treatment for 25 minutes. During the treatment process, keep the temperature of the dispersion system at 28 °C;

[0151] Third, slowly add 4 parts by weight of the nano iron powder under mild stirring conditions (210 rpm), control the feeding rate at 3.5 g / min. After the feeding is completed, continue to stir for 16 minutes, and perform ultrasonic treatment for 12 minutes (power is 210 W, continuous mode);

[0152] Finally, add 0.6 parts by weight of sodium citrate as a stabilizer, adjust the pH value to 6.8, age at 50 °C for 2.5 hours, and cool to room temperature to obtain component A.

[0153] (2) Preparation of component B:

[0154] First, dilute the commercial sodium silicate solution (40 wt%) to 26 wt%, add aluminum sulfate solution (Al2(SO4)3·18H2O, 1.2 wt%) for modification, add 0.6 wt% of polyethylene glycol (PEG1000), stir evenly, and age for 15 hours to obtain 1 part by weight of the modified sodium silicate;

[0155] Second, add 415 parts by weight of deionized water to a 600 ml reaction vessel, and add 0.6 parts by weight of a non-ionic surfactant (polyoxyethylene ether type);

[0156] Then, add 2.5 parts by weight of the sulfonated activated carbon under stirring conditions (325 rpm) and stir for 35 minutes;

[0157] Third, slowly add the modified sodium silicate solution under mild stirring conditions (160 rpm), and control the mass ratio of the solid content of activated carbon to sodium silicate to be 3.5:1;

[0158] Finally, after stirring evenly, cure at 60 °C for 2.5 hours, and cool to room temperature to obtain the Component B.

[0159] (3) Before use, mix the Component A and the Component B according to a weight ratio of 1.2:1.

[0160] The sulfonated activated carbon is prepared by soaking activated carbon in an aqueous solution of 0.8% sodium dodecylbenzenesulfonate, with a liquid-solid ratio of 10:1 (ml / g), a temperature of 61 °C, and a time of 4.5 hours. Then, filter, wash with deionized water until neutral, dry at 80 °C for 15 hours, and grind to a particle size of 8 μm to obtain the sulfonated activated carbon.

[0161] The graphene-enhanced high-efficiency degreaser of this example is applicable to the degreasing and anti-oxidation treatment of the stainless-steel surface. The use concentration is 15% of the original concentration, the treatment temperature is 28 °C, and the action time is 7 minutes. The experimental results show that the degreasing efficiency of this degreaser for the stainless-steel surface is 42% higher than that of the traditional emulsified degreaser, and the formed anti-oxidation film can provide a protection period of 4.5 months.

[0162] Example 5

[0163] A graphene-enhanced high-efficiency degreaser, comprising Component A and Component B. The degreaser is composed of the following components in parts by weight:

[0164] Component A: 2.5 parts by weight of reduced graphene oxide, 6 parts by weight of nano iron powder, 3 parts by weight of cationic surfactant;

[0165] Component B: 4 parts by weight of sulfonated activated carbon, 1.5 parts by weight of modified sodium silicate;

[0166] Among them, the weight ratio of Component A to Component B is 1.8:1.

[0167] The particle size range of the reduced graphene oxide is 450 mesh, the sheet thickness is 7 nm, the specific surface area is 600 m 2 / g, the oxygen content is 12%, and the C / O ratio is 7.

[0168] The nano iron powder is zero-valent iron powder with a core-shell structure. The core particle size is 75 nm, and the surface is coated with an ultrathin iron oxide shell layer (Fe / Fe3O4). The specific surface area is 30 m 2 / g.

[0169] The cationic surfactant is benzalkonium chloride, with a concentration of 33 wt% aqueous solution and an HLB value of 21.

[0170] The sulfonated activated carbon is mesoporous activated carbon modified by sodium dodecylbenzenesulfonate, with a particle size of 15 μm and a specific surface area of 1100 m 2 / g, the mesopore aperture is mainly distributed at 15 nm, and the sulfonic acid group content is 1.1 mmol / g.

[0171] The modified sodium silicate is sodium silicate double-modified by aluminum ions and polyethylene glycol, with a concentration of 38 wt% aqueous solution and a modulus (SiO2 / Na2O molar ratio) of 3.3.

[0172] The preparation method of the graphene-enhanced high-efficiency degreasing agent comprises the following steps:

[0173] (1) Preparation of component A:

[0174] First, add 735 parts by weight of deionized water to a 1000 ml reaction vessel;

[0175] Secondly, add 3 parts by weight of the cationic surfactant under stirring conditions (375 rpm) and stir for 13 minutes to form a solution;

[0176] Then, add 2.5 parts by weight of the reduced graphene oxide, and perform ultrasonic dispersion treatment for 30 minutes. Specifically, perform initial 5-minute high-power (87% output power) pulse mode (3 seconds on / 2 seconds off) treatment with an ultrasonic probe of 375 W power, and then perform subsequent 25-minute medium-power (57% output power) continuous mode treatment. During the treatment process, keep the temperature of the dispersion system at 32 °C;

[0177] Again, slowly add 6 parts by weight of the nano iron powder under gentle stirring conditions (235 rpm), control the feeding rate at 4.5 g / min, continue stirring for 18 minutes after the feeding is completed, and perform ultrasonic treatment for 13 minutes (power is 235 W, continuous mode);

[0178] Finally, add 0.8 part by weight of sodium citrate as a stabilizer, adjust the pH value to 7.2, age at 51 °C for 3.5 hours, and cool to room temperature to obtain the component A.

[0179] (2) Preparation of component B:

[0180] First, dilute the commercial sodium silicate solution (40 wt%) to 28 wt%, add an aluminum sulfate solution (Al2(SO4)3·18H2O, 1.7 wt%) for modification, add 0.8 wt% of polyethylene glycol (PEG1000), stir evenly, and age for 20 hours to obtain 1.5 parts by weight of the modified sodium silicate;

[0181] Secondly, add 435 parts by weight of deionized water to a 600 ml reaction vessel, and add 0.8 part by weight of a non-ionic surfactant (polyoxyethylene ether type);

[0182] Then, 4 parts by weight of the sulfonated activated carbon was added under stirring conditions (375 rpm), and the mixture was stirred for 40 minutes;

[0183] Again, the modified sodium silicate solution was slowly added under gentle stirring conditions (185 rpm), and the mass ratio of the solid content of the activated carbon to sodium silicate was controlled to be 3.2:1;

[0184] Finally, after stirring evenly, it was cured at 61 °C for 3.5 hours, cooled to room temperature, and the Component B was obtained.

[0185] (3) Before use, the Component A and the Component B were mixed at a weight ratio of 1.8:1.

[0186] The sulfonated activated carbon was prepared by soaking activated carbon in a 1.5% aqueous solution of sodium dodecylbenzenesulfonate, with a liquid-solid ratio of 10:1 (ml / g), a temperature of 63 °C, and a time of 5.5 hours. Then, it was filtered, washed with deionized water until neutral, dried at 80 °C for 20 hours, and ground to a particle size of 15 μm to obtain the sulfonated activated carbon.

[0187] The graphene-enhanced high-efficiency degreasing agent of this example is applicable to the degreasing and anti-oxidation treatment of the magnesium alloy surface, with a use concentration of 25% of the original concentration, a treatment temperature of 32 °C, and an action time of 6 minutes. The experimental results show that the degreasing efficiency of this degreasing agent on the magnesium alloy surface is 47% higher than that of the traditional surfactant degreasing agent, and the formed anti-oxidation film can provide a 5-month protection period.

[0188] Comparative Example 1 (blank control group, raw materials without modification treatment)

[0189] A degreasing agent, comprising Component A and Component B, and the degreasing agent is composed of the following components in parts by weight:

[0190] Component A: 2 parts by weight of ordinary graphite powder, 5 parts by weight of ordinary iron powder, 2 parts by weight of ordinary anionic surfactant (sodium dodecyl sulfate);

[0191] Component B: 3 parts by weight of ordinary activated carbon, 1 part by weight of ordinary sodium silicate;

[0192] Among them, the weight ratio of Component A to Component B is 1.5:1.

[0193] The particle size range of the ordinary graphite powder is 400 mesh, the thickness is variable, and the specific surface area is about 200 m 2 / g.

[0194] The particle size of the ordinary iron powder is 5 - 10 μm, without a core-shell structure, and the specific surface area is about 1 - 2 m 2 / g.

[0195] The ordinary anionic surfactant is sodium dodecyl sulfate (SDS), with a concentration of 30 wt% aqueous solution and an HLB value of 40.

[0196] The ordinary activated carbon is commercial activated carbon, with a particle size of 10 μm and a specific surface area of 600 m 2 / g, without sulfonic acid groups.

[0197] The ordinary sodium silicate is a commercial sodium silicate solution, with a concentration of 35 wt% aqueous solution, a modulus (SiO2 / Na2O molar ratio) of 3.2, and no aluminum ions and polyethylene glycol modification.

[0198] The preparation method of this degreaser is basically the same as that of Example 2, except that the raw materials are not modified and ordinary anionic surfactant is used to replace the cationic surfactant.

[0199] The degreaser of this comparative example is suitable for degreasing and anti-oxidation treatment of the aluminum alloy surface. The use concentration is 20% of the original concentration, the treatment temperature is 30 °C, and the action time is 8 minutes. The experimental results show that the degreasing efficiency of this degreaser on the aluminum alloy surface is low, and the treatment time needs to be extended to 20 minutes to achieve the basic degreasing effect, and there is no obvious anti-oxidation protection ability. Oxidation phenomenon begins to appear after about 2 weeks.

[0200] Comparative Example 2 (without graphene group)

[0201] A degreaser, comprising component A and component B, and the degreaser is composed of the following components in parts by weight:

[0202] Component A: 0 part by weight of reduced graphene oxide, 5 parts by weight of nano iron powder, 2 parts by weight of cationic surfactant;

[0203] Component B: 3 parts by weight of sulfonated activated carbon, 1 part by weight of modified sodium silicate;

[0204] Among them, the weight ratio of component A to component B is 1.5:1.

[0205] The preparation method of this degreaser is basically the same as that of Example 2, except that reduced graphene oxide is not added.

[0206] The degreaser of this comparative example is suitable for degreasing and anti-oxidation treatment of the aluminum alloy surface. The use concentration is 20% of the original concentration, the treatment temperature is 30 °C, and the action time is 8 minutes. The experimental results show that the degreasing efficiency of this degreaser on the aluminum alloy surface is about 25% lower than that of Example 2, the degreasing time needs to be extended to 12 minutes, and the protection period of the formed anti-oxidation film is only 1.5 months, which is significantly lower than the 4-month protection period of Example 2.

[0207] Comparative Example 3 (without nano iron powder group)

[0208] A degreasing agent, comprising component A and component B, and the degreasing agent is composed of the following components in parts by weight:

[0209] Component A: 2 parts by weight of reduced graphene oxide, 0 parts by weight of nano iron powder, 2 parts by weight of cationic surfactant;

[0210] Component B: 3 parts by weight of sulfonated activated carbon, 1 part by weight of modified sodium silicate;

[0211] Wherein, the weight ratio of component A to component B is 1.5:1.

[0212] The preparation method of this degreasing agent is basically the same as that of Example 2, except that nano iron powder is not added.

[0213] The degreasing agent of this comparative example is applicable to the degreasing and anti-oxidation treatment of the aluminum alloy surface, the use concentration is 20% of the original concentration, the treatment temperature is 30 °C, and the action time is 8 minutes. The experimental results show that the degreasing efficiency of this degreasing agent on the aluminum alloy surface is about 20% lower than that of Example 2, especially the removal effect on heavy oil stains is poor, the uniformity of the formed anti-oxidation film is poor, and the protection period is 2.5 months.

[0214] Comparative Example 4 (group without modified components)

[0215] A degreasing agent, comprising component A and component B, and the degreasing agent is composed of the following components in parts by weight:

[0216] Component A: 2 parts by weight of reduced graphene oxide, 5 parts by weight of nano iron powder, 2 parts by weight of cationic surfactant;

[0217] Component B: 3 parts by weight of ordinary activated carbon (not sulfonated), 1 part by weight of ordinary sodium silicate (not modified);

[0218] Wherein, the weight ratio of component A to component B is 1.5:1.

[0219] The preparation method of this degreasing agent is basically the same as that of Example 2, except that unmodified ordinary activated carbon and ordinary sodium silicate are used in component B.

[0220] The degreasing agent of this comparative example is applicable to the degreasing and anti-oxidation treatment of the aluminum alloy surface, the use concentration is 20% of the original concentration, the treatment temperature is 30 °C, and the action time is 8 minutes. The experimental results show that the degreasing efficiency of this degreasing agent on the aluminum alloy surface is about 15% lower than that of Example 2, the synergistic effect between component B and component A is significantly reduced, the compactness of the formed anti-oxidation film is poor, and the protection period is 2 months.

[0221] Comparative Example 5 (traditional alkaline degreasing agent)

[0222] A comparative experiment was carried out using a commercially available traditional alkaline degreasing agent. The main components of this alkaline degreasing agent are:

[0223] Sodium hydroxide: 15 wt%;

[0224] Sodium carbonate: 25 wt%;

[0225] Sodium tripolyphosphate: 10 wt%;

[0226] Sodium silicate: 5 wt%;

[0227] Non-ionic surfactant: 2 wt%;

[0228] Water: 43 wt%;

[0229] Use conditions: 10% aqueous solution, temperature 60 - 70 °C, treatment time 15 - 20 minutes.

[0230] This traditional alkaline degreaser is suitable for degreasing various metal surfaces, but needs to be used at a relatively high temperature, has low degreasing efficiency, and has no obvious anti-oxidation protection function. When treating aluminum alloy, there is a slight corrosion risk.

[0231] Comparative Example 6 (Traditional acidic degreaser)

[0232] A comparative experiment was carried out using a commercially available traditional acidic degreaser. The main components of this acidic degreaser are:

[0233] Phosphoric acid: 10 wt%;

[0234] Citric acid: 5 wt%

[0235] Ammonium bifluoride: 3 wt%;

[0236] Cationic surfactant: 2 wt%;

[0237] Non-ionic surfactant: 1 wt%;

[0238] Isopropyl alcohol: 10 wt%;

[0239] Water: 69 wt%.

[0240] Use conditions: 15% aqueous solution, temperature 40 - 50 °C, treatment time 10 - 15 minutes.

[0241] This traditional acidic degreaser is suitable for degreasing and rust removal on the surface of light metals (such as aluminum alloy), but causes greater environmental pollution and has no obvious anti-oxidation protection function. Long-term use may cause corrosion to the metal surface.

[0242] Comparative Example 7 (Traditional organic solvent degreaser)

[0243] A comparative experiment was carried out using a commercially available traditional organic solvent degreaser. The main components of this organic solvent degreaser are:

[0244] Trichloroethylene: 50 wt%

[0245] Petroleum ether: 30 wt%

[0246] Butyl acetate: 15 wt%

[0247] Emulsifier: 5 wt%

[0248] Usage conditions: Use the stock solution, soak at room temperature for 5 - 10 minutes.

[0249] This traditional organic solvent degreaser is suitable for degreasing oil stains on various metal surfaces, has good solubility for heavy oil stains, but is highly volatile, harmful to the environment and human health, and has no anti-oxidation protection function. It has been restricted in many countries and regions.

[0250] Comparative Example 8 (Traditional Emulsifying Degreaser)

[0251] A commercially available traditional emulsifying degreaser was used for comparative experiments. The main components of this emulsifying degreaser are:

[0252] Sodium alkylbenzene sulfonate: 10 wt%

[0253] Fatty alcohol polyoxyethylene ether: 8 wt%

[0254] Alkylamide: 5 wt%

[0255] Diethanolamine: 3 wt%

[0256] Ethylene glycol monobutyl ether: 5 wt%

[0257] Water: 69 wt%

[0258] Usage conditions: 20% aqueous solution, temperature 40 - 50 °C, treatment time 10 - 15 minutes.

[0259] This traditional emulsifying degreaser is suitable for degreasing medium oil stains on various metal surfaces, has good environmental protection, but the degreasing efficiency is average, has poor effect on heavy oil stains, and has no obvious anti-oxidation protection function.

[0260] In order to comprehensively evaluate the performance of the graphene-enhanced high-efficiency degreaser of the present invention, the following test experiments were designed:

[0261] 1. Degreasing efficiency test:

[0262] Testing method: Under standard conditions (25 °C), the surfaces of metal specimens (galvanized steel sheets, aluminum alloys, copper alloys, and stainless steels) of the same size (100 mm × 100 mm × 2 mm) were evenly coated with standard oil stains (a mixture of mineral oil and solid impurities, with a thickness of approximately 100 μm). After standing for 2 hours, they were treated with the degreasers of each example and comparative example of the present invention at the specified concentration, and the time required to completely remove the oil stains and the degreasing efficiency were recorded.

[0263] Evaluation indicators:

[0264] Degreasing rate (%): The proportion of oil stain removal on the metal surface after treatment, measured by the mass method.

[0265] Degreasing time (min): The time required to completely remove the oil stains.

[0266] 2. Anti-oxidation performance test

[0267] Testing method: The metal specimens after degreasing treatment were dried at room temperature for 24 hours, and then subjected to a salt spray test (ASTM B117 standard). The time when obvious rust appeared on the metal surface was recorded, and the impedance characteristics of the protective film on the metal surface were tested by electrochemical impedance spectroscopy (EIS).

[0268] Evaluation indicators:

[0269] Anti-oxidation time (months): The time when no obvious rust appears on the metal surface in the standard environment.

[0270] Impedance value (Ω·cm 2 ): An electrochemical parameter characterizing the barrier performance of the protective film.

[0271] 3. Surface topography analysis

[0272] Testing method: A scanning electron microscope (SEM) and an atomic force microscope (AFM) were used to observe the microscopic topography and protective film structure of the metal surface after degreasing treatment, and to evaluate the distribution state of graphene in the protective film.

[0273] Evaluation indicators:

[0274] Film thickness (nm): The thickness of the anti-oxidation film formed.

[0275] Film uniformity: A qualitative evaluation of the evenness of the protective film coverage.

[0276] Graphene distribution: The distribution state of graphene in the protective film.

[0277] The test results are as follows:

[0278] Table 1. Degreasing and anti-oxidation properties of different degreasers on aluminum alloy

[0279]

[0280]

[0281] Film layer uniformity rating criteria: Excellent, with uniform coverage, no cracks and defects; Good, with basically uniform coverage and a small number of micro-defects; General, with non-uniform coverage and obvious defects; Poor, with extremely non-uniform coverage, a large number of defects and cracks; None, where no effective protective film is formed.

[0282] Table 2. Degreasing and anti-oxidation properties of different degreasers on copper alloy

[0283]

[0284] Table 3. Degreasing and anti-oxidation properties of different degreasers on galvanized steel sheet

[0285]

[0286] It can be seen from the above test results that:

[0287] 1) Synergistic effect of graphene and nano-iron powder: The degreasing efficiency and anti-oxidation properties of Comparative Example 2 (without graphene) and Comparative Example 3 (without nano-iron powder) are significantly lower than those of the examples of the present invention, proving that graphene and nano-iron powder play a key synergistic role in the present invention. In particular, the anti-oxidation time of Comparative Example 2 is only 37.5% of that of Example 2, indicating that reduced graphene oxide plays a decisive role in forming a durable protective film.

[0288] 2) Importance of modification treatment: The performance of Comparative Example 1 (unmodified raw materials) and Comparative Example 4 (without modified components) is much lower than that of the examples of the present invention, indicating that specific modification treatment of raw materials (such as reduced graphene oxide, core-shell structured nano-iron powder, sulfonated activated carbon, and aluminum / PEG-modified sodium silicate) is crucial for improving degreasing efficiency and anti-oxidation properties.

[0289] 3) Advantages of the A / B two-component design: From the test results, the A / B two-component design of the present invention (Component A is responsible for high-efficiency degreasing and the formation of the anti-oxidation film skeleton, and Component B is responsible for deep adsorption of oil stains and densification of the protective film) forms a highly efficient synergistic effect, while this synergistic effect is not reflected in the comparative examples, and the performance drops significantly.

[0290] 4) Advantages compared with traditional degreasers: The examples of the present invention are significantly superior to traditional degreasers (Comparative Examples 5-8) in terms of degreasing efficiency, degreasing time, anti-oxidation properties, and environmental friendliness. Especially in terms of anti-oxidation properties, traditional degreasers have almost no anti-oxidation protection function or a very short protection period (0.1 - 0.8 months), while the present invention can provide a long-term protection of 3 - 6 months.

[0291] 5) Optimal formulation and process parameters: From the test results, it can be determined that Example 3 has the best performance. Its formulation is Component A (3 parts by weight of reduced graphene oxide, 8 parts by weight of nano iron powder, 4 parts by weight of cationic surfactant) and Component B (5 parts by weight of sulfonated activated carbon, 2 parts by weight of modified sodium silicate), and the A / B component ratio is 2:1. This indicates that a higher content of functional components and a reasonable component ratio are beneficial for achieving the best performance.

[0292] In summary, through specific modification of components such as graphene, nano iron powder, activated carbon, and sodium silicate, and adopting an A / B two-component design, the present invention realizes the synergistic effect among components, significantly improves the degreasing efficiency and anti-oxidation performance, and is completely superior to unmodified raw materials and traditional degreasers, providing an innovative solution for the field of metal surface treatment.

[0293] The excellent performance of the graphene-enhanced high-efficiency degreaser of the present invention stems from its unique action mechanism:

[0294] 1. High-efficiency degreasing mechanism:

[0295] The high-efficiency degreasing effect of the present invention is mainly based on the following synergistic effects:

[0296] First, the cationic surfactant (benzalkonium chloride) forms an adsorption layer on the metal surface, reducing the adhesion between the oil stain and the metal surface and emulsifying the oil stain molecules at the same time.

[0297] Second, the two-dimensional sheet structure of reduced graphene oxide provides a huge specific surface area (300 - 700 m 2 / g), generating a strong adsorption effect on the oil stain molecules. Some oxygen groups on the graphene surface enhance its adsorption ability for polar pollutants, while the hydrophobic graphene regions have high-efficiency adsorption for non-polar oil stains.

[0298] Third, the nano iron powder and graphene form a unique physical and electrochemical synergistic effect. The core-shell structure of the nano iron powder (Fe / Fe3O4) not only provides catalytic activity but also maintains sufficient stability. When the nano iron powder contacts the graphene, a micro-battery structure is formed, promoting electron transfer, enhancing the interfacial activity, and accelerating the oil stain emulsification and peeling process.

[0299] Finally, sulfonated activated carbon, as the main component of Component B, provides a large number of mesoporous structures (2 - 20 nm) and a high specific surface area (800 - 1200 m 2 / g). These mesopores match the size of the oil stain molecules, and combined with the polar effect of the surface sulfonic acid groups, they have a strong adsorption and fixation ability for the emulsified oil stain molecules, preventing the oil stain from redepositing on the metal surface.

[0300] 2. Anti-oxidation film-forming mechanism:

[0301] The anti-oxidation protection mechanism of the present invention is based on the following innovative designs:

[0302] First, the modified sodium silicate hydrolyzes on the metal surface to form a silicate network structure, which is regulated by aluminum ions to form a denser aluminosilicate film. The introduction of polyethylene glycol increases the flexibility and adhesion of the film layer.

[0303] Second, the reduced graphene oxide sheets are embedded in the silicate network during the film formation process to form a composite protective layer similar to a "brick wall" structure. The two-dimensional sheet structure of graphene greatly extends the penetration paths of oxygen and moisture, significantly improving the barrier performance of the protective film.

[0304] Third, the presence of nano iron powder provides an additional protection mechanism. The surface-oxidized nano iron powder (Fe / Fe3O4) forms dispersed reduction centers in the protective film, which can consume the penetrated oxygen molecules, further enhancing the anti-oxidation effect. In addition, the conductive network formed by nano iron powder and graphene also provides a certain cathodic protection effect.

[0305] Finally, the sulfonic acid groups in the sulfonated activated carbon form a coordination effect with the metal surface, enhancing the binding force between the entire protective film and the metal surface and improving the stability and durability of the protective film.

[0306] 3. A / B two-component synergistic mechanism:

[0307] The present invention adopts an A / B two-component design, which not only solves the long-term stability problem between the components but also realizes the synergistic effect of multiple functions:

[0308] In component A, the reduced graphene oxide and nano iron powder form a uniformly dispersed system under the stabilization of a cationic surfactant, mainly responsible for the degreasing process and the formation of the anti-oxidation film skeleton.

[0309] In component B, the sulfonated activated carbon and the modified sodium silicate form a composite system, mainly responsible for the deep adsorption of oil stains and the densification of the protective film.

[0310] When the two components are used in combination, a synergistic effect is formed between the functional materials: graphene and nano iron powder provide efficient degreasing and skeleton support; sulfonated activated carbon provides deep adsorption; modified sodium silicate provides film-forming ability. This unique combination design enables the degreasing agent of the present invention to achieve high-efficiency degreasing in a short time and at the same time form a long-lasting anti-oxidation protective film on the metal surface.

[0311] In summary, through the careful proportioning and synergistic effect between the components, the graphene-enhanced high-efficiency degreasing agent of the present invention achieves degreasing efficiency and anti-oxidation performance that are difficult to achieve by traditional degreasing agents, providing an innovative solution for the field of metal surface treatment.

[0312] The graphene-enhanced high-efficiency degreaser of the present invention has broad industrial application prospects:

[0313] 1) In the field of mechanical manufacturing: It can be used for surface degreasing and anti-oxidation treatment after machining of mechanical parts, improving the quality and service life of subsequent processes such as painting and electroplating.

[0314] 2) In the automotive manufacturing industry: It is suitable for the pretreatment process of body metal parts, improving the painting quality and anti-corrosion performance.

[0315] 3) In the electronics industry: It can be used for the cleaning treatment of metal substrates of electronic components, improving the reliability of components.

[0316] 4) In the aerospace field: It is suitable for the surface treatment of aerospace precision metal parts, meeting the high-standard anti-corrosion requirements.

[0317] 5) In the household appliance manufacturing industry: It can be used for degreasing and anti-oxidation treatment of metal housings of household appliances, improving the appearance quality and service life of products.

[0318] 6) In the metal products industry: It is suitable for the surface pretreatment of various metal products, improving the added value of products.

[0319] The graphene-enhanced high-efficiency degreaser of the present invention adopts a water-based formula, does not contain organic solvents, phosphates and heavy metals, conforms to the development trend of modern industrial green environmental protection, and has good market promotion prospects.

Claims

1. A graphene-enhanced high-efficiency degreaser, characterized in that, It includes component A and component B, and the degreasing agent is composed of the following components by weight: Component A: 1-3 parts by weight of reduced graphene oxide, 3-8 parts by weight of nano iron powder, 1-4 parts by weight of cationic surfactant; Component B: 2-5 parts by weight of sulfonated activated carbon, 0.5-2 parts by weight of modified sodium silicate; Among them, the weight ratio of component A to component B is 1-2:

1.

2. The graphene-enhanced high-efficiency degreaser according to claim 1, wherein The particle size range of the reduced graphene oxide is 300 - 500 mesh, the sheet thickness is 1 - 10 nm, the specific surface area is 300 - 700 m 2 / g, the oxygen content is 5 - 15%, and the C / O ratio is controlled at 6 - 10.

3. The graphene-enhanced high-efficiency degreaser according to claim 1, wherein The nano iron powder is zero-valent iron powder with a core-shell structure, the core particle size is 20-100 nm, the surface is coated with an ultrathin iron oxide shell layer (Fe / Fe3O4), and the specific surface area is 15-35 m 2 / g.

4. The graphene-enhanced high-efficiency degreaser according to claim 1, wherein, The cationic surfactant is benzalkonium chloride, with a concentration of 30-35 wt% aqueous solution and an HLB value of 18-22.

5. The graphene-enhanced high-efficiency degreaser according to claim 1, characterized in that, The sulfonated activated carbon is mesoporous activated carbon modified by sodium dodecylbenzenesulfonate, with a particle size of 5 - 20 μm, a specific surface area of 800 - 1200 m 2 / g, the mesopore diameter is mainly distributed in the range of 2 - 20 nm, and the sulfonic acid group content is 0.8 - 1.2 mmol / g; the modified sodium silicate is sodium silicate double-modified by aluminum ions and polyethylene glycol, with a concentration of 35 - 40 wt% aqueous solution and a modulus (SiO2 / Na2O molar ratio) of 3.0 - 3.

5.

6. A method for preparing a graphene-enhanced high-efficiency degreasing agent according to any one of claims 1-5, characterized in that, It includes the following steps: (1) Preparation of component A; (2) Preparation of component B; (3) Before use, mix component A and component B according to a weight ratio of 1-2:

1.

7. The preparation method according to claim 6, characterized in that, The preparation of component A in step (1) includes: First, add 700-750 parts by weight of deionized water to the reaction vessel; Secondly, add 1-4 parts by weight of the cationic surfactant under stirring conditions and stir for 10-15 minutes to form a solution; Then, add 1-3 parts by weight of the reduced graphene oxide and perform ultrasonic dispersion treatment for 30 minutes; Again, slowly add 3-8 parts by weight of the nano iron powder under gentle stirring conditions. After the feeding is completed, continue to stir for 15-20 minutes and perform ultrasonic treatment for 10-15 minutes; Finally, add 0.5-1.0 parts by weight of sodium citrate as a stabilizer, adjust the pH value to 6.5-7.5, age at 50±2°C for 2-4 hours, and cool to room temperature to obtain component A.

8. The preparation method according to claim 6, characterized in that, The preparation of component B in step (2) includes: First, dilute the commercial sodium silicate solution to 25-30 wt%, add aluminum sulfate solution and 0.5-1.0 wt% of polyethylene glycol for modification, stir evenly, and age for 12-24 hours to obtain 0.5-2 parts by weight of the modified sodium silicate; Secondly, add 400-450 parts by weight of deionized water and 0.5-1.0 parts by weight of non-ionic surfactant to another reaction vessel; Then, add 2-5 parts by weight of the sulfonated activated carbon under stirring conditions and stir for 30-45 minutes; Again, slowly add the modified sodium silicate solution under gentle stirring conditions, and control the mass ratio of the solid content of activated carbon to sodium silicate to be 3:1 to 4:1; Finally, after stirring evenly, cure at 60±2°C for 2-4 hours and cool to room temperature to obtain component B.

9. The preparation method according to claim 7, wherein The ultrasonic dispersion treatment includes the following steps: First, perform an initial 5-minute high-power (80-90% output power) pulse mode (3 seconds on / 2 seconds off) treatment with a ultrasonic probe of 300-400W power, and then perform a subsequent 25-minute medium-power (50-60% output power) continuous mode treatment. During the treatment process, keep the temperature of the dispersion system at 25-35°C.

10. The preparation method according to claim 7, characterized in that, In the above step, the sulfonated activated carbon is prepared by soaking activated carbon in an aqueous solution of sodium dodecylbenzenesulfonate at 0.5-2.0%, with a liquid-solid ratio of 10:1 (ml / g), a temperature of 60±5°C, and a time of 4-6 hours. Then, it is filtered, washed with deionized water until neutral, dried at 80±5°C for 12-24 hours, and ground to a particle size of 5-20 μm to obtain the sulfonated activated carbon.

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