Environmentally friendly scale inhibitor and preparation method thereof

Abstract

The present invention relates to the field of water treatment technology, and in particular to an environmentally friendly scale inhibitor and a preparation method thereof, comprising the following components by weight: 60 to 80 parts of a composite polymer scale inhibitor, 10 to 30 parts of a corrosion inhibitor, and 2 to 6 parts of a surfactant; the composite polymer scale inhibitor comprises a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid. The environmentally friendly scale inhibitor of the present invention has excellent scale inhibition and corrosion inhibition performance, is evenly dispersed in water, and can reduce the generation of microbial slime to further improve the scale inhibition capacity.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to an environmentally friendly scale inhibitor and a preparation method thereof. Background Art

[0002] The generation of scale is usually due to the fact that certain components in the medium reach an oversaturated state under the operating environment, resulting in crystallization and precipitation. These scale layers will not only reduce the efficiency of the system, but may also aggravate the pore corrosion at the contact point of the pipeline, posing a threat to the safety of the system. Therefore, physical and chemical methods are often used in industrial production to slow down the growth of scale, among which chemical descaling mainly relies on the addition of scale inhibitors.

[0003] Scale inhibitor is an important water treatment chemical used to prevent or delay the deposition of insoluble salts in water. This type of agent can disperse the sparingly soluble inorganic salts in water, prevent or interfere with the precipitation and scaling of these salts on the metal surface, thereby maintaining good heat transfer effects in metal equipment. There are many types of scale inhibitors, which can be classified from multiple angles, including inorganic scale inhibitors, organic scale inhibitors, phosphate scale inhibitors, polymer scale inhibitors, etc. Among them, polymer scale inhibitors are the most common type on the market.

[0004] The mechanism of action of scale inhibitors mainly includes solubilization, coagulation and dispersion, electrostatic repulsion, crystal distortion, etc. These mechanisms work together to enable scale inhibitors to effectively prevent the formation and deposition of scale in water. For example, scale inhibitors can collide and complex with scale-forming ions to form soluble complexes, allowing some scale-forming ions to stably exist in the medium. In addition, scale inhibitors can also interfere with the normal formation process of crystals, making the deposited scale layer loose and porous, with poor resistance to hydraulic impact, thereby preventing scale deposition. Scale inhibitors play a key role in many industries involving water resource recycling and equipment corrosion and scale prevention. For example, in the power industry, scale inhibitors are used in circulating cooling water systems to prevent scaling inside equipment such as boilers, steam generators, and heat exchangers; in the petrochemical industry, scale inhibitors are used to inhibit the deposition of inorganic salts in drilling fluids to protect wellbores and pipelines from being blocked; in the water treatment industry, reverse osmosis scale inhibitors are essential agents that can effectively prevent inorganic salts from depositing on the membrane surface and ensure the stability and water production of membrane components.

[0005] There are many studies on scale inhibitors at present. For example, CN103332795A discloses "a phosphorus-free composite corrosion inhibitor and scale inhibitor" which is made of phosphorus-free and non-nitrogen green corrosion inhibitor and scale inhibitor, environmentally friendly biopolymer scale inhibitor, passivation film type inorganic corrosion inhibitor, corrosion inhibitor and scale inhibitor synergist, natural organic polymer, high-efficiency corrosion inhibitor and surfactant. The scale inhibitor has good corrosion inhibition and scale inhibition effects.

[0006] For example, CN102603086A discloses "a corrosion inhibitor and scale inhibitor for cooling water in the petrochemical industry" which is mainly composed of an organic phosphine carboxylic acid corrosion inhibitor, an organic polyphosphonic acid corrosion inhibitor, a polymer scale inhibitor, a metal ion chelating agent, a surfactant, a zinc salt, a functional additive and water. The scale inhibitor has a low phosphine content and better corrosion and scale inhibition performance.

[0007] However, the scale inhibitor composition in the above-mentioned patent is complex, which increases the production cost. In addition, the generation of some scale is also related to microbial metabolism, and the above-mentioned patent does not mention and solve the problem of reducing the generation of sludge by microbial metabolism.

[0008] Therefore, it is urgent to develop an environmentally friendly scale inhibitor that has excellent scale and corrosion inhibition properties, disperses evenly in water, and can reduce the production of microbial sludge. Summary of the invention

[0009] The main purpose of the present invention is to provide an environmentally friendly scale inhibitor and a preparation method thereof. The environmentally friendly scale inhibitor has excellent scale and corrosion inhibition performance, is evenly dispersed in water, and can reduce the generation of microbial sludge, providing a new idea for the preparation of scale inhibitors.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] On the one hand, the present invention provides an environmentally friendly scale inhibitor, comprising the following components by weight: 60 to 80 parts of a composite polymer scale inhibitor, 10 to 30 parts of a corrosion inhibitor and 2 to 6 parts of a surfactant; the composite polymer scale inhibitor comprises a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid.

[0012] In some embodiments, the mass ratio of the modified gallic acid-itaconic acid binary copolymer to polyepoxysuccinic acid is 1:(0.5-0.8).

[0013] The present application adopts a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid for synergistic use, which can improve the sufficient efficiency of the scale inhibitor. The reason may be that the groups in the polyepoxysuccinic acid structure are relatively simple. When used in combination with the modified gallic acid-itaconic acid binary copolymer of the present application, the scale inhibitor can chelate with the metal ions in the circulating water through different mechanisms of multiple groups, thereby improving the scale inhibition performance of the scale inhibitor.

[0014] In addition, by adjusting the mass ratio of the modified gallic acid-itaconic acid copolymer and polyepoxysuccinic acid, it is possible to prevent the scale inhibitor from causing a decrease in the pH of the water and causing corrosion to the equipment.

[0015] In some embodiments, the method for preparing the modified gallic acid-itaconic acid binary copolymer comprises the following steps:

[0016] (1) 3-Butene-1-ol and gallic acid are mixed and added into dichloromethane, concentrated sulfuric acid is added thereto, the temperature is raised to 40-50°C and stirred at a constant temperature for 1-3 hours, and after the reaction is completed, modified gallic acid is extracted;

[0017] (2) The modified gallic acid, itaconic acid, azobisisobutyronitrile and toluene in step (1) are stirred and mixed uniformly, filled with inert protective gas, heated to 60-80° C. and stirred at a constant temperature for 6-8 hours. After the reaction is completed, centrifugation, filtration and washing are performed to obtain a modified gallic acid-itaconic acid copolymer.

[0018] In the past, scale inhibitors mainly used polyepoxysuccinic acid as the main scale inhibitor component, which had limited scale inhibition performance and was often used in a compound form. The modified gallic acid-itaconic acid binary copolymer of the present application can be compounded with polyepoxysuccinic acid to synergistically act, which can not only improve the scale inhibition efficiency of the scale inhibitor, but also the two can form cross-linked substances through hydrogen bonds to adhere to the surface of metal equipment, further preventing the deposition and formation of scale.

[0019] In some embodiments, the molar ratio of 3-butene-1-ol to gallic acid is (1-1.3):1.

[0020] In some embodiments, in step (2), the mass ratio of the modified gallic acid to itaconic acid is 1:(0.3-0.6).

[0021] In some embodiments, the mass of the azobisisobutyronitrile is 0.6-1% of the total mass of the modified gallic acid and itaconic acid.

[0022] In some embodiments, the corrosion inhibitor is any one of imidazoline, benzimidazole and thiazole.

[0023] In some embodiments, the method for preparing the surfactant comprises the following steps:

[0024] Step 1, mixing the hydrophobically modified starch and the phosphate buffer into a mixed solution of 8-13 wt %;

[0025] Step 2: Add the modified α-amylase to the mixed solution in step 1, raise the temperature to 60-70°C and shake for 20-30 minutes. After the reaction is completed, inactivate the enzyme and concentrate to obtain a surfactant.

[0026] In some embodiments, the method for preparing the hydrophobically modified starch comprises the following steps:

[0027] A1. Under an inert gas atmosphere, 3-bromopyrrolidine aldehyde and the compound shown in formula I are

[0028] (I) was mixed and added to acetone, the temperature was raised to reflux state, and the mixture was stirred at constant temperature for 40 to 50 hours. After the reaction was completed, the mixture was concentrated and dried under reduced pressure, and then subjected to column chromatography to obtain the compound shown in Formula II

[0029] (II);

[0030] A2. Under an inert gas atmosphere, the compound of formula II in step A1, 3-butenoic acid, triphenylphosphine palladium acetate and sodium peracetate are mixed, added to tetrahydrofuran, heated to reflux and stirred at constant temperature for 24 to 28 hours, and after the reaction is completed, column chromatography is performed to obtain a compound of formula III.

[0031] (III);

[0032] A3, starch and deionized water are mixed to form a 10-30wt% emulsion, sodium silicate is added to the system, and then urea is added to adjust the pH of the system to 9-10, the temperature is raised to 80-90°C, the compound represented by formula III in step A2 is added to the system and stirred at a constant temperature for 1-3h, and then cooled to room temperature to obtain hydrophobically modified starch;

[0033] Wherein n is an integer of 7 to 16, and R is a halogen.

[0034] In some embodiments, in step A1, the molar ratio of 3-bromopyrrolidine aldehyde to the compound represented by formula I is 1:(1-2).

[0035] In some embodiments, in step A2, the molar ratio of the compound represented by formula II to 3-butenoic acid is 1:(1~1.5).

[0036] In some embodiments, in step A3, the mass ratio of the starch to the compound represented by formula III is 1:(0.2~0.6).

[0037] In some embodiments, the method for preparing the modified α-amylase comprises the following steps:

[0038] B1, dissolving chitosan in acetic acid solution to form a chitosan solution;

[0039] B2, mixing and dispersing the regenerated cellulose and water to form a mixed solution;

[0040] B3, mixing the chitosan solution in step B1 with the polyvinyl alcohol solution, and then adding the mixed solution in step B2 to the system, stirring at room temperature for 1 to 2 hours to form an emulsion, then filtering, and freeze-drying to obtain a chitosan / regenerated cellulose gel;

[0041] B4. Under an inert protective gas atmosphere, cool thionyl chloride to -5~0°C, add 1,3-acetone dicarboxylic acid at a constant temperature, heat to room temperature and stir at a constant temperature for 4~6 hours. After the reaction is completed, quench, extract, combine the organic phases, and concentrate and dry under reduced pressure to obtain compound A;

[0042] B5, adding compound A in B4 to the chitosan / regenerated cellulose gel in step B3, adding tetrahydrofuran, heating to 50-60°C and stirring at a constant temperature for 1-3 hours, filtering after the reaction is completed, freeze-drying, washing with ethanol solution, and freeze-drying again to obtain modified chitosan / regenerated cellulose gel;

[0043] B6. Mix α-amylase with a phosphate buffer having a pH of 6 to 7, then add the modified chitosan / regenerated cellulose gel in step B5, react under ultrasonic vibration at room temperature for 20 to 30 hours, then filter and rinse with a phosphate buffer having a pH of 6 to 7 to obtain a modified α-amylase.

[0044] In some embodiments, the mass ratio of chitosan to regenerated cellulose is 1:(1-3).

[0045] In some embodiments, in step B5, the mass ratio of compound A to chitosan / regenerated cellulose gel is (1.2~1.8):1.

[0046] In some embodiments, the mass of the modified α-amylase is 0.01-0.1% of the mass of the hydrophobic modified starch.

[0047] Another aspect of the present invention provides a method for preparing an environmentally friendly scale inhibitor, comprising the following steps: mixing and stirring a composite polymer scale inhibitor, a corrosion inhibitor and a surfactant to obtain the environmentally friendly scale inhibitor.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The environmentally friendly scale inhibitor of the present invention adopts a composite polymer scale inhibitor, a corrosion inhibitor and a surfactant for synergistic use, providing a new idea for the preparation of scale inhibitors. The scale inhibitor not only has excellent scale inhibition and corrosion inhibition performance, but also disperses evenly in water and can reduce the generation of microbial slime.

[0050] (2) The composite polymer scale inhibitor of the present invention is composed of a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid. It chelates with metal ions in circulating water through different mechanisms of multiple groups, thereby improving the scale inhibition performance of the scale inhibitor. At the same time, the use of a specific mass ratio can prevent the scale inhibitor from causing a decrease in the pH of the water quality and causing corrosion to the equipment.

[0051] (3) The surfactant of the present invention is prepared by enzymatic hydrolysis of hydrophobic modified starch with modified α-amylase. The surfactant is suitable for the field of water treatment. It not only has good emulsification stability, but also has a certain antibacterial effect. It can reduce the generation of microbial sludge in circulating water and further improve the scale inhibition efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the compound represented by formula II in Preparation Example 1.

[0053] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the compound represented by formula III in Preparation Example 1. DETAILED DESCRIPTION

[0054] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0055] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0056] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. Various modifications and variations may be made to the specific embodiments of the present invention specification without departing from the scope or spirit of the present invention, which will be apparent to those skilled in the art. Other embodiments obtained from the present invention specification will be apparent to the technician. The present application specification and examples are exemplary only.

[0057] It should be noted that the operations of "drying", "filtering" and "stirring" described in the present invention are routine operations of those skilled in the art and can be selected according to actual operations.

[0058] In the following preparation examples, starch was purchased from Langfang Pengcai Fine Chemical Co., Ltd.; chitosan was purchased from Anhui Xinsheng Biotechnology Co., Ltd.; lignin fiber was purchased from Shandong Taicheng Fiber Co., Ltd.; α-amylase was purchased from Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd.; and polyepoxysuccinic acid was purchased from Shandong Haoyao New Materials Co., Ltd.

[0059] Preparation Example 1

[0060] The preparation method of hydrophobically modified starch comprises the following steps:

[0061] A1. Under N2 atmosphere, 50mmol 3-bromopyridine aldehyde and 75mmol 1-chlorodecane were added to 100mL acetone, the temperature was raised to reflux state, and the mixture was stirred at constant temperature for 45h. After the reaction was completed, the mixture was concentrated and dried under reduced pressure, and then subjected to column chromatography to obtain the compound shown in Formula II

[0062] (II);

[0063] Figure 1 The NMR image of the compound shown in Formula II is analyzed as follows: 1 H NMR (400 MHz, ) δ 9.66 (s,1H), 8.83 (dd, J = 8.0, 1.3 Hz, 2H), 8.38 (dd, J = 12.0, 1.4 Hz, 2H), 7.93(dd, J = 8.0, 6.2 Hz, 2H), 4.52 (t, J = 4.0 Hz, 3H), 2.04 (tt, J = 8.0, 6.5Hz, 3H), 1.63-1.44 (m, 1H), 1.35-1.21 (m, 10H), 0.96-0.81 (m, 3H);

[0064] A2. Under N2 atmosphere, 50 mmol of the compound of formula II in step A1, 20 mmol of 3-butenoic acid, 2.5 mmol of triphenylphosphine palladium acetate and 150 mmol of sodium peracetate were mixed, added to 200 mL of tetrahydrofuran, heated to reflux and stirred at constant temperature for 26 hours. After the reaction was completed, column chromatography was performed to obtain a compound of formula III.

[0065] (III);

[0066] Figure 2 The NMR image of the compound shown in Formula III is analyzed as follows: 1H NMR (400 MHz, ) δ 9.48 (dd,J = 4.0, 1.3 Hz, 1H), 9.02 (ddd, J = 8.0, 2.3, 1.4 Hz, 1H), 8.89 (dd, J =4.0, 1.5 Hz, 1H), 8.20-8.04 (m, 2H), 4.65 (t, J = 8.0 Hz, 2H), 2.09 (tt, J =8.0, 6.3 Hz, 2H), 1.66-1.53 ​​(m, 5H), 1.38-1.23 (m, 5H), 0.95-0.82 (m, 2H);

[0067] A3. Mix 10g of starch with deionized water to prepare a 20wt% emulsion, add 0.05g of sodium silicate to the system, then add urea to adjust the pH of the system to 9.5, raise the temperature to 85°C, add 4g of the compound represented by formula III in step A2 to the system and stir at a constant temperature for 2h, then cool to room temperature to obtain hydrophobically modified starch.

[0068] Preparation Example 2

[0069] The preparation method of modified α-amylase comprises the following steps:

[0070] B1, dissolving 2 g of chitosan in 100 mL of 1 wt % acetic acid solution to form a chitosan solution;

[0071] B2, 4 g of lignin fiber was mixed and dispersed evenly with 200 mL of water to form a mixed solution;

[0072] B3, mixing the chitosan solution in step B1 with 50 mL of 10 wt% polyvinyl alcohol solution, and then adding the mixed solution in step B2 to the system, stirring at room temperature for 1.5 h to form an emulsion, then filtering and freeze-drying to obtain a chitosan / lignin fiber gel;

[0073] B4. Under N2 atmosphere, cool 100 mL of thionyl chloride to -3°C, add 6 g of 1,3-acetone dicarboxylic acid at constant temperature, heat to room temperature and stir at constant temperature for 5 h. After the reaction is completed, quench, extract, combine the organic phases, concentrate and dry under reduced pressure to obtain compound A;

[0074] B5, adding 4.8g of compound A in B4 to 3g of chitosan / lignin fiber gel in step B3, adding 100mL of tetrahydrofuran, heating to 55°C and stirring at constant temperature for 2h, filtering after the reaction, freeze-drying, washing with 65wt% ethanol solution, and freeze-drying again to obtain modified chitosan / lignin fiber gel;

[0075] B6. Mix 10 g of α-amylase with 800 mL of phosphate buffer at pH 6.5, then add 2 g of the modified chitosan / lignin fiber gel in step B5, react under ultrasonic vibration at room temperature for 25 h, then filter and rinse with phosphate buffer at pH 6.5 to obtain modified α-amylase.

[0076] Preparation Example 3

[0077] The preparation method of a surfactant comprises the following steps:

[0078] Step 1: Mix 2 g of hydrophobically modified starch with 20 mL of pH 6.5 phosphate buffer to prepare a 10 wt% mixed solution;

[0079] Step 2: Add 0.01 g of modified α-amylase to the mixed solution in step 1, heat to 65° C. and shake for 25 min. After the reaction is completed, inactivate the enzyme and concentrate to obtain a surfactant.

[0080] Wherein, the hydrophobic modified starch is prepared by Preparation Example 1, and the modified α-amylase is prepared by Preparation Example 2.

[0081] Preparation Example 4

[0082] The specific implementation method of the surfactant is the same as that of Preparation Example 3, except that an equal mass of α-amylase is used instead of the modified α-amylase.

[0083] Preparation Example 5

[0084] The preparation method of the surfactant is the same as that of Preparation Example 3, except that an equal mass of starch is used instead of the hydrophobically modified starch.

[0085] Preparation Example 6

[0086] The preparation method of the modified gallic acid-itaconic acid binary copolymer comprises the following steps:

[0087] (1) 240 mmol of 3-butene-1-ol and 200 mmol of gallic acid were mixed and added to 300 mL of dichloromethane, to which 1 g of 98 wt% concentrated sulfuric acid was added, and the temperature was raised to 45 °C and stirred for 2 h. After the reaction was completed, modified gallic acid was extracted;

[0088] (2) 10 g of the modified gallic acid prepared in step (1), 4 g of itaconic acid, 0.1 g of azobisisobutyronitrile and 300 mL of toluene were stirred and mixed uniformly, filled with nitrogen, heated to 70° C. and stirred at this temperature for 7 h. After the reaction was completed, the mixture was centrifuged, filtered and washed to obtain a modified gallic acid-itaconic acid copolymer.

[0089] Preparation Example 7

[0090] The preparation method of the modified benzoic acid-itaconic acid binary copolymer is the same as that of Preparation Example 4, except that an equal mole of benzoic acid is used instead of gallic acid.

[0091] Preparation Example 8

[0092] The preparation method of the modified terephthalic acid-itaconic acid binary copolymer is the same as that of Preparation Example 4, except that an equal molar amount of terephthalic acid is used instead of gallic acid.

[0093] Preparation Example 9

[0094] The preparation method of the modified gallic acid-itaconic acid binary copolymer is the same as that of Preparation Example 4, except that the mass of itaconic acid is 8 g.

[0095] Example 1

[0096] An environmentally friendly scale inhibitor comprises the following components by weight: 70 parts of a composite polymer scale inhibitor, 20 parts of imidazoline and 4 parts of a surfactant; the composite polymer scale inhibitor comprises a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid in a mass ratio of 1:0.7.

[0097] Among them, the modified gallic acid-itaconic acid binary copolymer is prepared by Preparation Example 6; and the surfactant is prepared by Preparation Example 3.

[0098] The preparation method of the environmentally friendly scale inhibitor comprises the following steps: mixing and stirring a composite polymer scale inhibitor, imidazoline and a surfactant to obtain the environmentally friendly scale inhibitor.

[0099] Example 2

[0100] An environmentally friendly scale inhibitor comprises the following components by weight: 60 parts of a composite polymer scale inhibitor, 10 parts of imidazoline and 2 parts of a surfactant; the composite polymer scale inhibitor comprises a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid in a mass ratio of 1:0.5.

[0101] Among them, the modified gallic acid-itaconic acid binary copolymer is prepared by Preparation Example 6; and the surfactant is prepared by Preparation Example 3.

[0102] The preparation method of the environmentally friendly scale inhibitor comprises the following steps: mixing and stirring a composite polymer scale inhibitor, imidazoline and a surfactant to obtain the environmentally friendly scale inhibitor.

[0103] Example 3

[0104] An environmentally friendly scale inhibitor comprises the following components by weight: 80 parts of a composite polymer scale inhibitor, 30 parts of imidazoline and 6 parts of a surfactant; the composite polymer scale inhibitor comprises a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid in a mass ratio of 1:0.8.

[0105] Among them, the modified gallic acid-itaconic acid binary copolymer is prepared by Preparation Example 6; and the surfactant is prepared by Preparation Example 3.

[0106] The preparation method of the environmentally friendly scale inhibitor comprises the following steps: mixing and stirring a composite polymer scale inhibitor, imidazoline and a surfactant to obtain the environmentally friendly scale inhibitor.

[0107] Example 4

[0108] An environmentally friendly scale inhibitor and a preparation method thereof. The specific implementation method is the same as Example 1, except that the modified gallic acid-itaconic acid binary copolymer is prepared by Preparation Example 9.

[0109] Example 5

[0110] An environmentally friendly scale inhibitor and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the mass ratio of the modified gallic acid-itaconic acid binary copolymer to the polyepoxysuccinic acid is 1:1.

[0111] Example 6

[0112] An environmentally friendly scale inhibitor and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the surfactant is prepared by Preparation Example 4.

[0113] Example 7

[0114] An environmentally friendly scale inhibitor and a preparation method thereof. The specific implementation method is the same as Example 1, except that the surfactant is prepared by Preparation Example 5.

[0115] Comparative Example 1

[0116] An environmentally friendly scale inhibitor and a preparation method thereof. The specific implementation method is the same as Example 1, except that an equal mass portion of a modified benzoic acid-itaconic acid binary copolymer is used to replace the modified gallic acid-itaconic acid binary copolymer, and the modified benzoic acid-itaconic acid binary copolymer is prepared by Preparation Example 7.

[0117] Comparative Example 2

[0118] An environmentally friendly scale inhibitor and a preparation method thereof. The specific implementation method is the same as Example 1, except that an equal mass portion of a modified terephthalic acid-itaconic acid binary copolymer is used to replace the modified gallic acid-itaconic acid binary copolymer, and the modified terephthalic acid-itaconic acid binary copolymer is prepared by Preparation Example 8.

[0119] Performance Test:

[0120] (1) Scale inhibition test: refer to GB / T16632-2008 "Determination of scale inhibition performance of water treatment agents - calcium carbonate deposition method" for determination;

[0121] (2) Corrosion rate: Referring to GBT18175-2000 "Determination of corrosion inhibition performance of water treatment agents - Rotating plate method", the static corrosion inhibition performance of the mixed corrosion and scale inhibitor samples was tested.

[0122] The scale inhibitors prepared in the examples and comparative examples were tested according to the above method. The test results are shown in Table 1.

[0123] Table 1

[0124]

[0125] According to the data in Table 1, the scale inhibitors prepared in Examples 1 to 3 have good scale inhibition and corrosion inhibition capabilities; in Example 4, the mass ratio of modified gallic acid and itaconic acid was changed, resulting in an enhanced corrosion ability of the scale inhibitor to metals; in Example 5, the mass ratio of modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid was changed, resulting in an enhanced corrosion ability of the scale inhibitor to metals; in Example 6, the same mass of α-amylase was used instead of modified α-amylase, resulting in a weakened hydrolysis ability of starch under the same conditions, a weakened surface activity, and thus uneven dispersion of the scale inhibitor, resulting in The scale inhibition and corrosion inhibition performance are weakened; in Example 6, since the same mass of starch is used instead of hydrophobic modified starch, the scale inhibitor is also unevenly dispersed, resulting in weakened scale inhibition and corrosion inhibition performance; in Comparative Example 1, since the same mass of modified benzoic acid-itaconic acid copolymer is used instead of modified gallic acid-itaconic acid copolymer, the scale inhibition performance of the scale inhibitor is weakened; in Comparative Example 2, since the same mass of modified terephthalic acid-itaconic acid copolymer is used instead of modified gallic acid-itaconic acid copolymer, the scale inhibitor has an enhanced ability to corrode metals, while the scale inhibition ability is reduced.

[0126] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An environmentally friendly scale inhibitor, characterized in that: The invention comprises the following components by weight: 60 to 80 parts of a composite polymer scale inhibitor, 10 to 30 parts of a corrosion inhibitor and 2 to 6 parts of a surfactant; the composite polymer scale inhibitor comprises a modified gallic acid-itaconic acid binary copolymer and polyepoxysuccinic acid; The preparation method of the modified gallic acid-itaconic acid binary copolymer comprises the following steps: (1) 3-Butene-1-ol and gallic acid are mixed and added into dichloromethane, concentrated sulfuric acid is added thereto, the temperature is raised to 40-50°C and stirred at a constant temperature for 1-3 hours, and after the reaction is completed, modified gallic acid is extracted; (2) The modified gallic acid, itaconic acid, azobisisobutyronitrile and toluene in step (1) are stirred and mixed uniformly, filled with inert protective gas, heated to 60-80° C. and stirred at a constant temperature for 6-8 hours. After the reaction is completed, centrifugation, filtration and washing are performed to obtain a modified gallic acid-itaconic acid copolymer.

2. The environmentally friendly antiscalant according to claim 1, characterized in that: The mass ratio of the modified gallic acid-itaconic acid binary copolymer to polyepoxysuccinic acid is 1:(0.5-0.8).

3. The environmentally friendly scale inhibitor according to claim 1, characterized in that: The molar ratio of the 3-butene-1-ol to gallic acid is (1-1.3):

1.

4. The environmentally friendly antiscalant according to claim 1, characterized in that: In step (2), the mass ratio of the modified gallic acid to itaconic acid is 1:(0.3-0.6).

5. The environmentally friendly antiscalant according to claim 1, characterized in that: The mass of the azobisisobutyronitrile is 0.6-1% of the total mass of the modified gallic acid and itaconic acid.

6. The environmentally friendly antiscalant according to claim 1, characterized in that: The corrosion inhibitor is any one of imidazoline, benzimidazole and thiazole.

7. The environmentally friendly antiscalant according to claim 1, characterized in that: The preparation method of the surfactant comprises the following steps: Step 1, mixing the hydrophobically modified starch and the phosphate buffer into a mixed solution of 8-13 wt %; Step 2: Add the modified α-amylase to the mixed solution in step 1, raise the temperature to 60-70°C and shake for 20-30 minutes. After the reaction is completed, inactivate the enzyme and concentrate to obtain a surfactant.

8. The environmentally friendly antiscalant according to claim 7, characterized in that: The mass of the modified α-amylase is 0.01-0.1% of the mass of the hydrophobic modified starch.

9. A method for preparing the environmentally friendly scale inhibitor according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing and stirring a composite polymer scale inhibitor, a corrosion inhibitor and a surfactant uniformly to obtain an environmentally friendly scale inhibitor.

Images