A circulating water treatment agent containing dibromocyanoacetamide and preparation method thereof

Abstract

The invention relates to a circulating water treatment agent containing dibromocyanoacetamide and a preparation method thereof, belonging to the technical field of water treatment agents. The circulating water treatment agent has excellent scale inhibition performance by utilizing the synergistic effect of a carboxymethyl cellulose graft copolymer, polyaspartic acid and an acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer. The acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer can infiltrate and penetrate into the interior of biological slime, peel off the biological slime deposited on the surface of a pipeline and disperse it in the circulating water to avoid secondary aggregation, and can also adsorb bacteria and algae killed by an antibacterial agent to avoid the killed bacteria and algae from aggregating to form a large amount of biological slime deposited on the surface of the pipeline, and the synergistic effect of two antibacterial agents, dibromocyanoacetamide and isothiazolinone, is used to significantly improve the sterilization efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment agents, and in particular relates to a circulating water treatment agent containing dibromocyanoacetamide and a preparation method thereof. Background Art

[0002] In the process of industrial circulating water treatment, corrosion, scaling, and microbial problems are often encountered. With the improvement of water treatment technology, most of the corrosion and scaling problems have been well solved, but the biological slime problem of the system is still prominent. Biological slime adheres to the pipes and equipment of the system, reducing the heat exchange effect of the equipment, causing increased energy consumption, and easily forming under-scale corrosion, shortening the service life of the equipment. Biological slime is mainly composed of microbial cells and polysaccharides and protein-like sticky substances bonded together. It has strong adhesion and viscosity. Therefore, the control and cleaning of biological slime is a more complex and difficult problem in industrial circulating cooling water systems.

[0003] At present, fungicides have become the first choice for solving the above problems. Currently, commonly used fungicides are divided into oxidizing fungicides and non-oxidizing fungicides. Oxidizing fungicides have strong oxidizing properties and use their oxidizing properties to kill microorganisms, but their penetration ability is weak and they have no obvious effect on groups of algae and biological slime. Non-oxidizing fungicides can poison certain parts of microorganisms and then kill them, and are less affected by pH and reducing substances in water. However, a single non-oxidizing fungicide will produce drug resistance after long-term use, resulting in a decrease in the sterilization rate. At the same time, non-oxidizing fungicides have poor exfoliation and dispersion effects on biological slime, and cannot effectively kill microorganisms in biological slime, resulting in a decrease in the sterilization rate. Therefore, it is necessary to provide a circulating water treatment agent that can solve the above problems. Summary of the invention

[0004] The invention aims to provide a circulating water treatment agent containing dibromocyanoacetamide and a preparation method thereof. The circulating water treatment agent has excellent scale inhibition performance by utilizing the synergistic effect of carboxymethyl cellulose graft copolymer, polyaspartic acid and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer. The acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer can infiltrate and penetrate into the biological slime, peel off the biological slime deposited on the surface of the pipeline and disperse it in the circulating water to avoid secondary aggregation. At the same time, the biological slime can also be adsorbed by the bacteria and algae killed by the antibacterial agent to avoid the killed bacteria and algae from aggregating to form a large amount of biological slime deposited on the surface of the pipeline. The synergistic effect of two antibacterial agents, dibromocyanoacetamide and isothiazolinone, is used to significantly improve the sterilization efficiency.

[0005] The technical problem to be solved by the present invention is as follows: Oxidizing fungicides have strong oxidizing properties and are used to kill microorganisms by their oxidizing properties, but they have weak penetrating ability and have no obvious effect on algae colonies and biological slime. Non-oxidizing fungicides can poison certain parts of microorganisms and kill them, and are less affected by pH and reducing substances in water. However, long-term use of a single non-oxidizing fungicide will produce drug resistance, resulting in a decrease in the sterilization rate. At the same time, non-oxidizing fungicides have poor stripping and dispersion effects on biological slime, and cannot effectively kill microorganisms in biological slime, resulting in a decrease in the sterilization rate.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A circulating water treatment agent containing dibromocyanoacetamide comprises, by mass percentage, 15-30% of carboxymethyl cellulose graft copolymer, 15-25% of polyaspartic acid, 20-30% of acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-acrylic acid long-chain alkyl ester-allyl cyclodextrin copolymer, 5-15% of dibromocyanoacetamide, 2-10% of isothiazolinone, and the balance is water.

[0008] Further, the isothiazolinone includes at least one of 5-chloro-2-methyl-4-isothiazoline-3-one and 2-methyl-4-isothiazoline-3-one;

[0009] Furthermore, the preparation method of the carboxymethyl cellulose graft copolymer comprises the following steps:

[0010] Dissolve carboxymethyl cellulose in deionized water, introduce inert gas, stir at 40-70°C for 1.5-3h, add persulfate aqueous solution, react for 15-20min, add acrylic acid and allyl β-cyclodextrin, react at 60-75°C for 3-5h, filter, wash, dry and grind to obtain carboxymethyl cellulose graft copolymer.

[0011] In the above preparation process, carboxymethyl cellulose, acrylic acid and allyl β-cyclodextrin are used as reaction raw materials to prepare a carboxymethyl cellulose graft copolymer. The carboxymethyl cellulose graft copolymer contains a large number of carboxyl functional groups and has good water solubility. The carboxyl functional groups can react with scale-forming metal ions Ca 2+ Mg 2+ In addition, β-cyclodextrin can capture Ca 2+ Mg 2+ It enters its cavity, causing the inorganic salt scale lattice to be distorted, further preventing the formation of inorganic salt scale.

[0012] Furthermore, the persulfate is at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0013] Furthermore, the persulfate is 0.5-2% of the total mass of carboxymethyl cellulose, acrylic acid and allyl β-cyclodextrin.

[0014] Furthermore, the mass ratio of carboxymethyl cellulose, deionized water, acrylic acid and allyl β-cyclodextrin is 1:(20-30):(5-10):(1-2.5).

[0015] Furthermore, the polyaspartic acid is a polyaspartic acid derivative, and the preparation method comprises the following steps:

[0016] Dissolve polysuccinimide in deionized water, add sodium hydroxide solution containing 4-aminophthalic acid and react at 40-60°C for 7-10 hours. After the reaction, adjust to neutrality, then precipitate with anhydrous ethanol, separate the solid and liquid, and dry to obtain a polyaspartic acid derivative.

[0017] 4-aminophthalic acid is introduced into the polyaspartic acid derivative prepared above. 4-aminophthalic acid contains a carboxyl functional group and a benzene ring structure, which improves the scale inhibition efficiency and temperature resistance of the polyaspartic acid derivative.

[0018] Furthermore, the mass concentration of the sodium hydroxide solution is 10-15%.

[0019] Furthermore, the molar ratio of polysuccinimide to 4-aminophthalic acid is 1:(0.8-1.2).

[0020] Furthermore, the dosage ratio of polysuccinimide to deionized water is (1.1-1.3) g: (80-120) mL.

[0021] Furthermore, in the sodium hydroxide solution containing 4-aminophthalic acid, the usage ratio of 4-aminophthalic acid to the sodium hydroxide solution is (1.1-1.3) g: (15-20) mL.

[0022] Furthermore, the preparation method of acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer comprises the following steps:

[0023] Acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid, allyl cyclodextrin and sodium dodecyl sulfonate are added into deionized water, and long-chain alkyl acrylate is added after stirring and dissolving. Inert gas is introduced, and an initiator is added. The reaction is carried out at 40-60° C. for 4-7 hours, and the reaction is carried out by filtering, washing, drying and crushing to obtain acrylic acid-2-acrylamide-2-methylpropane sulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer.

[0024] The long alkyl chain of the long-chain alkyl acrylate in the above-prepared acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer can infiltrate and penetrate into the biological slime, and peel off the biological slime deposited on the surface of the pipeline. Cyclodextrin has a structure that is hydrophilic on the outside and hydrophobic on the inside, and can adsorb bacteria and algae killed by the antibacterial agent, and avoid the killed bacteria and algae from aggregating to form a large amount of biological slime deposited on the surface of the pipeline. Therefore, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer can infiltrate and penetrate into the biological slime, and peel off the biological slime deposited on the surface of the pipeline and disperse it in the circulating water to avoid secondary aggregation. At the same time, it can also adsorb bacteria and algae killed by the antibacterial agent, and avoid the killed bacteria and algae from aggregating to form a large amount of biological slime deposited on the surface of the pipeline. In addition, the long alkyl chain introduced into the side chain of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer can improve the dispersibility of the copolymer and avoid the problem of re-aggregation and precipitation of the copolymer adsorbed bacteria and algae. The acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer has a large number of carboxylic acid groups, amide groups and sulfonic acid groups, and also has the ability to adsorb Ca 2+ Mg 2+ The cyclodextrin entering the cavity enables the copolymer to effectively inhibit the formation of inorganic salt scale.

[0025] Furthermore, the mass ratio of acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid, long-chain alkyl acrylate, allyl cyclodextrin, sodium dodecyl sulfonate and initiator is (15-30): (5-10): (0.5-2): (3-7): (0.8-2.5): (0.02-0.1).

[0026] Furthermore, the long-chain alkyl acrylate includes at least one of lauryl acrylate, tetradecyl acrylate, hexadecyl acrylate, octadecyl acrylate, hexyl acrylate, and octyl acrylate.

[0027] Furthermore, the molecular weight of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer is 2000-8000.

[0028] Furthermore, the initiator is ammonium persulfate and sodium bisulfite, and the molar ratio of ammonium persulfate to sodium bisulfite is 1:(1-1.5).

[0029] A method for preparing a circulating water treatment agent containing dibromocyanoacetamide comprises the following steps:

[0030] Carboxymethyl cellulose graft copolymer, polyaspartic acid and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-acrylic acid long-chain alkyl ester-allyl cyclodextrin copolymer are sequentially added into water, stirred and dissolved at 50-60°C, and then dibromocyanoacetamide and isothiazolinone are sequentially added and mixed and stirred to obtain a circulating water treatment agent containing dibromocyanoacetamide.

[0031] Beneficial effects of the present invention:

[0032] (1) In the technical solution of the present invention, the synergistic effect of carboxymethyl cellulose graft copolymer, polyaspartic acid and acrylic acid-2-acrylamide-2-methylpropane sulfonic acid-long chain alkyl acrylate-allyl cyclodextrin copolymer is utilized to have excellent scale inhibition performance.

[0033] (2) In the technical solution of the present invention, the prepared acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer can infiltrate and penetrate into the interior of the biological slime, peel off the biological slime deposited on the surface of the pipeline and disperse it in the circulating water to avoid secondary aggregation. At the same time, it can also adsorb bacteria and algae killed by antibacterial agents to prevent the killed bacteria and algae from aggregating to form a large amount of biological slime deposited on the surface of the pipeline.

[0034] (3) In the technical solution of the present invention, the long alkyl chain introduced into the side chain of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer can improve the dispersibility of the copolymer and avoid the problem of re-aggregation and precipitation of the copolymer adsorbed bacteria and algae.

[0035] (4) In the technical solution of the present invention, dibromocyanoacetamide is a broad-spectrum bactericide with rapid bactericidal effect. Even at relatively low concentrations, it can still exert excellent broad-spectrum bactericidal performance. Isothiazolinone can break the bonds between bacteria and algae proteins to kill bacteria and has a good biological slime stripping effect. The two antibacterial agents work synergistically to significantly improve the bactericidal efficiency. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a method for preparing a carboxymethyl cellulose graft copolymer, comprising the following steps:

[0039] 20 g of carboxymethyl cellulose was dissolved in 400 g of deionized water, nitrogen was introduced, and the mixture was stirred at 40°C for 1.5 h. 70 mL of an aqueous solution of ammonium persulfate having a mass concentration of 1% was added, and the mixture was reacted for 15 min. 100 g of acrylic acid and 20 g of allyl β-cyclodextrin were added, and the mixture was reacted at 60°C for 3 h. The mixture was filtered, washed, dried, and ground to obtain a carboxymethyl cellulose graft copolymer.

[0040] Comparative Example 1

[0041] Compared with Example 1, allyl β-cyclodextrin was not added in Comparative Example 1, and other steps and raw materials were the same as those in Example 1.

[0042] Example 2

[0043] This embodiment provides a method for preparing a carboxymethyl cellulose graft copolymer, comprising the following steps:

[0044] 20 g of carboxymethyl cellulose was dissolved in 500 g of deionized water, nitrogen was introduced, and the mixture was stirred at 55° C. for 2 h. 220 mL of a 1% potassium persulfate aqueous solution was added and the mixture was reacted for 15 min. 160 g of acrylic acid and 38 g of allyl β-cyclodextrin were added and the mixture was reacted at 70° C. for 4 h. The mixture was filtered, washed, dried, and ground to obtain a carboxymethyl cellulose graft copolymer.

[0045] Example 3

[0046] This embodiment provides a method for preparing a carboxymethyl cellulose graft copolymer, comprising the following steps:

[0047] 20 g of carboxymethyl cellulose was dissolved in 600 g of deionized water, nitrogen was introduced, and the mixture was stirred at 70°C for 3 h. 500 mL of a 1% sodium persulfate aqueous solution was added and the mixture was reacted for 20 min. 200 g of acrylic acid and 50 g of allyl β-cyclodextrin were added and the mixture was reacted at 75°C for 5 h. The mixture was filtered, washed, dried, and ground to obtain a carboxymethyl cellulose graft copolymer.

[0048] Example 4

[0049] This embodiment provides a method for preparing a polyaspartic acid derivative, comprising the following steps:

[0050] 22 g of polysuccinimide was dissolved in 1.6 L of deionized water to obtain a polysuccinimide solution. 4-aminophthalic acid was added to a sodium hydroxide solution with a mass concentration of 10% (the amount ratio of 4-aminophthalic acid to the sodium hydroxide solution was 1.1 g: 15 mL) to obtain a sodium hydroxide solution containing 4-aminophthalic acid. The sodium hydroxide solution containing 4-aminophthalic acid was added to the polysuccinimide solution (the molar ratio of polysuccinimide to 4-aminophthalic acid was 1: 0.8), and the mixture was reacted at 40°C for 7 h. After the reaction was completed, the mixture was adjusted to neutral, and then precipitated with anhydrous ethanol, and then solid-liquid separation and drying were performed to obtain a polyaspartic acid derivative.

[0051] Example 5

[0052] This embodiment provides a method for preparing a polyaspartic acid derivative, comprising the following steps:

[0053] 24 g of polysuccinimide was dissolved in 2 L of deionized water to obtain a polysuccinimide solution. 4-aminophthalic acid was added to a sodium hydroxide solution with a mass concentration of 12% (the amount ratio of 4-aminophthalic acid to the sodium hydroxide solution was 1.1 g: 20 mL) to obtain a sodium hydroxide solution containing 4-aminophthalic acid. The sodium hydroxide solution containing 4-aminophthalic acid was added to the polysuccinimide solution (the molar ratio of polysuccinimide to 4-aminophthalic acid was 1:1), and the mixture was reacted at 50°C for 9 h. After the reaction was completed, the mixture was adjusted to neutral, and then precipitated with anhydrous ethanol, followed by solid-liquid separation and drying to obtain a polyaspartic acid derivative.

[0054] Example 6

[0055] This embodiment provides a method for preparing a polyaspartic acid derivative, comprising the following steps:

[0056] 26 g of polysuccinimide was dissolved in 2.4 L of deionized water to obtain a polysuccinimide solution. 4-aminophthalic acid was added to a sodium hydroxide solution with a mass concentration of 15% (the amount ratio of 4-aminophthalic acid to the sodium hydroxide solution was 1.3 g: 20 mL) to obtain a sodium hydroxide solution containing 4-aminophthalic acid. The sodium hydroxide solution containing 4-aminophthalic acid was added to the polysuccinimide solution (the molar ratio of polysuccinimide to 4-aminophthalic acid was 1: 1.2), and the mixture was reacted at 60°C for 10 h. After the reaction was completed, the mixture was adjusted to neutral, and then precipitated with anhydrous ethanol, and then solid-liquid separation and drying were performed to obtain a polyaspartic acid derivative.

[0057] Example 7

[0058] This embodiment provides a method for preparing an acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer, comprising the following steps:

[0059] 15g of acrylic acid, 5g of 2-acrylamide-2-methylpropanesulfonic acid, 3g of allyl β-cyclodextrin and 0.8g of sodium dodecyl sulfonate were added into 170mL of deionized water, stirred and dissolved, 0.5g of dodecyl acrylate was added, inert gas was introduced, 0.02g of initiator (the molar ratio of ammonium persulfate to sodium bisulfite was 1:1) was added, the mixture was reacted at 40°C for 7h, filtered, washed, dried and crushed to obtain acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer with a molecular weight of 2000.

[0060] Comparative Example 2

[0061] Compared with Example 7, allyl β-cyclodextrin was not added in Comparative Example 2, and other steps and raw materials were the same as those in Example 7.

[0062] Comparative Example 3

[0063] Compared with Example 7, no lauryl acrylate was added in Comparative Example 3, and the other steps and raw materials were the same as those in Example 7.

[0064] Example 8

[0065] This embodiment provides a method for preparing an acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer, comprising the following steps:

[0066] 22g of acrylic acid, 7g of 2-acrylamide-2-methylpropanesulfonic acid, 5g of allyl β-cyclodextrin and 1.8g of sodium dodecyl sulfonate were added to 180mL of deionized water, and 1.2g of hexadecyl acrylate was added after stirring to dissolve. Inert gas was introduced, and 0.06g of initiator (the molar ratio of ammonium persulfate to sodium bisulfite was 1:1.2) was added. The mixture was reacted at 50°C for 6h, filtered, washed, dried and crushed to obtain an acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer with a molecular weight of 5000.

[0067] Example 9

[0068] This embodiment provides a method for preparing an acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer, comprising the following steps:

[0069] 30 g of acrylic acid, 10 g of 2-acrylamide-2-methylpropanesulfonic acid, 7 g of allyl β-cyclodextrin and 2.5 g of sodium dodecylsulfonate were added to 160 mL of deionized water, stirred and dissolved, and then 2 g of octadecyl acrylate was added. Inert gas was introduced, and 0.1 g of initiator (the molar ratio of ammonium persulfate to sodium bisulfite was 1:1.5) was added. The mixture was reacted at 60° C. for 4 h, filtered, washed, dried and crushed to obtain an acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer with a molecular weight of 8000.

[0070] Example 10

[0071] A circulating water treatment agent containing dibromocyanoacetamide comprises, by mass percentage, 15% of the carboxymethyl cellulose graft copolymer prepared in Example 1, 20% of the polyaspartic acid derivative prepared in Example 4, 25% of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-acrylic acid long-chain alkyl ester-allyl cyclodextrin copolymer prepared in Example 7, 5% of dibromocyanoacetamide, 4% of 5-chloro-2-methyl-4-isothiazoline-3-one, and the balance is water.

[0072] A method for preparing a circulating water treatment agent containing dibromocyanoacetamide comprises the following steps:

[0073] The above-mentioned carboxymethyl cellulose graft copolymer, polyaspartic acid and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer are added into water in sequence, stirred and dissolved at 50°C for 2 hours, and then dibromocyanoacetamide and 5-chloro-2-methyl-4-isothiazoline-3-one are added in sequence and mixed and stirred for 1 hour to obtain a circulating water treatment agent containing dibromocyanoacetamide.

[0074] Embodiment 11

[0075] A circulating water treatment agent containing dibromocyanoacetamide, comprising, by mass percentage, 22% of the carboxymethyl cellulose graft copolymer prepared in Example 2, 17% of the polyaspartic acid derivative prepared in Example 5, 23% of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-acrylic acid long-chain alkyl ester-allyl cyclodextrin copolymer prepared in Example 8, 8% of dibromocyanoacetamide, 2% of 5-chloro-2-methyl-4-isothiazoline-3-one, and the balance of water.

[0076] A method for preparing a circulating water treatment agent containing dibromocyanoacetamide comprises the following steps:

[0077] The above-mentioned carboxymethyl cellulose graft copolymer, polyaspartic acid and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer are added into water in sequence, stirred and dissolved at 55°C for 3 hours, and then dibromocyanoacetamide and 5-chloro-2-methyl-4-isothiazoline-3-one are added in sequence and mixed and stirred for 1.5 hours to obtain a circulating water treatment agent containing dibromocyanoacetamide.

[0078] Example 12

[0079] A circulating water treatment agent containing dibromocyanoacetamide, comprising, by mass percentage, 30% of the carboxymethyl cellulose graft copolymer prepared in Example 3, 15% of the polyaspartic acid derivative prepared in Example 6, 20% of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-acrylic acid long-chain alkyl ester-allyl cyclodextrin copolymer prepared in Example 9, 13% of dibromocyanoacetamide, 5% of 2-methyl-4-isothiazoline-3-one, and the balance of water.

[0080] A method for preparing a circulating water treatment agent containing dibromocyanoacetamide comprises the following steps:

[0081] The above-mentioned carboxymethyl cellulose graft copolymer, polyaspartic acid and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer are added into water in sequence, stirred and dissolved at 60°C for 4 hours, and then dibromocyanoacetamide and 2-methyl-4-isothiazoline-3-one are added in sequence and mixed and stirred for 2 hours to obtain a circulating water treatment agent containing dibromocyanoacetamide.

[0082] Comparative Example 4

[0083] Compared with Example 10, in Comparative Example 4, the carboxymethyl cellulose graft copolymer is replaced by the substance obtained in Comparative Example 1, and the other steps and raw materials are the same as those in Example 10.

[0084] Comparative Example 5

[0085] Compared with Example 10, in Comparative Example 5, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer is replaced with the substance prepared in Comparative Example 2, and other steps and raw materials are synchronized with Example 10.

[0086] Comparative Example 6

[0087] Compared with Example 10, in Comparative Example 6, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer is replaced with the substance prepared in Comparative Example 3, and other steps and raw materials are synchronized with Example 10.

[0088] Comparative Example 7

[0089] Compared with Example 10, in Comparative Example 7, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer was not added, and other steps and raw materials were the same as those in Example 10.

[0090] Comparative Example 8

[0091] Compared with Example 10, dibromocyanoacetamide was not added in Comparative Example 8, and the other steps and raw materials were the same as those in Example 10.

[0092] Comparative Example 9

[0093] Compared with Example 10, 5-chloro-2-methyl-4-isothiazoline-3-one was not added in Comparative Example 9, and other steps and raw materials were the same as those in Example 10.

[0094] Performance Testing

[0095] (1) Scale inhibition performance: According to the method of GB / T 16632-2019 "Calcium carbonate deposition method for evaluating the scale inhibition performance of water treatment agents", water was prepared for a static scale inhibition test. In the calcium carbonate scale inhibition test, the calcium ion concentration was 720 mg / L, the bicarbonate ion concentration was 1098 mg / L, and the water treatment agent concentration was 10 mg / L; the test temperature was 80°C, and after maintaining for 12 hours, the scale inhibition rate was measured;

[0096] (2) Bioslime stripping performance: Take several 250mL conical flasks, add 50mL of bioslime and 50mL of distilled water respectively, and ensure that the concentration of the added bioslime is consistent. After shaking, add the water treatment agents prepared in Examples 10-12 and Comparative Examples 4-9 respectively, and the concentration of the water treatment agents after addition is 10mg / L, and shake immediately. Then place it on a rotator and rotate it at a speed of 150r / min for 24h. First filter with filter paper, then filter with a 0.2μm microporous filter membrane, and measure the concentration of polysaccharides and proteins in the filtrate. The higher the concentration of polysaccharides and proteins in the filtrate, the better the stripping performance of the agent on bioslime;

[0097] (3) Dispersibility of biological slime: Take several 250mL conical flasks, add 50mL of biological slime and 50mL of distilled water respectively, and ensure that the mass concentration of the added biological slime is consistent. After shaking well, add the water treatment agents prepared in Examples 10-12 and Comparative Examples 4-9 respectively, and the concentration of the water treatment agents after addition is 10mg / L respectively, and shake well immediately. Let it stand at room temperature, and then test the turbidity of the supernatant 4h after adding the water treatment agent; the larger the turbidity, the better the dispersibility.

[0098] (4) Sterilization rate test: Refer to the requirements of GB / T 14643.1-2009 "Determination of bacteria and algae in industrial circulating cooling water Part 1: Determination of slime-forming bacteria by plate count method" for heterotrophic bacteria sterilization rate test.

[0099] Table 1

[0100]

[0101] It can be seen from the data in Table 1 that the water treatment agent prepared by the present invention has excellent scale inhibition and bactericidal properties, and has good peeling and dispersing properties on biological slime. It can be seen from the data of Comparative Example 10 and Comparative Example 4 that the scale inhibition rate and biological slime dispersing performance are reduced due to the absence of allyl β-cyclodextrin in the carboxymethyl cellulose graft copolymer. It can be seen from the data of Comparative Example 10 and Comparative Example 5 that the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer is replaced with acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate copolymer. Due to the absence of allyl β-cyclodextrin, the scale inhibition rate and biological slime dispersing performance are reduced. From the data of Example 10 and Comparative Example 6, it can be seen that the acrylic acid-2-acrylamide-2-methylpropane sulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer is replaced with acrylic acid-2-acrylamide-2-methylpropane sulfonic acid-allyl cyclodextrin copolymer, and the biological slime stripping performance is reduced due to the lack of the addition of long-chain alkyl acrylate. From the data of Example 10 and Comparative Example 7, it can be seen that the biological slime stripping performance, biological slime dispersion performance and scale inhibition rate of the water treatment agent are reduced due to the lack of the addition of acrylic acid-2-acrylamide-2-methylpropane sulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer in the water treatment agent. From the data of Example 10 and Comparative Examples 8 and 9, it can be seen that there is a synergistic effect between dibromocyanoacetamide and 5-chloro-2-methyl-4-isothiazoline-3-one, which jointly improves the bactericidal performance of the water treatment agent.

[0102] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0103] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A circulating water treatment agent containing dibromocyanoacetamide, characterized in that: Calculated by mass percentage, it includes 15-30% carboxymethyl cellulose graft copolymer, 15-25% polyaspartic acid, 20-30% acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-acrylic acid long chain alkyl ester-allyl cyclodextrin copolymer, 5-15% dibromocyanoacetamide, 2-10% isothiazolinone, and the balance is water; The preparation method of the carboxymethyl cellulose graft copolymer comprises the following steps: Dissolve carboxymethyl cellulose in deionized water, introduce inert gas, stir at 40-70°C for 1.5-3h, add persulfate aqueous solution, react for 15-20min, add acrylic acid and allyl β-cyclodextrin, react at 60-75°C for 3-5h, filter, wash, dry and grind to obtain carboxymethyl cellulose graft copolymer; The polyaspartic acid is a polyaspartic acid derivative, and the preparation method comprises the following steps: Dissolve polysuccinimide in deionized water, add sodium hydroxide solution containing 4-aminophthalic acid, react at 40-60°C for 7-10 hours, adjust to neutral after the reaction, then precipitate with anhydrous ethanol, separate the solid and liquid, and dry to obtain a polyaspartic acid derivative; The preparation method of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer comprises the following steps: Add acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid, allyl cyclodextrin and sodium dodecyl sulfonate into deionized water, stir and dissolve, then add long-chain alkyl acrylate, introduce inert gas, add initiator, react at 40-60° C. for 4-7 hours, filter, wash, dry and crush to obtain acrylic acid-2-acrylamide-2-methylpropane sulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer; The long-chain alkyl acrylate includes at least one of lauryl acrylate, tetradecyl acrylate, hexadecyl acrylate, octadecyl acrylate, hexyl acrylate, and octyl acrylate.

2. A circulating water treatment agent containing dibromocyanoacetamide according to claim 1, characterized in that: The mass ratio of the carboxymethyl cellulose, deionized water, acrylic acid and allyl beta-cyclodextrin is 1:(20-30):(5-10):(1-2.5).

3. A circulating water treatment agent containing dibromocyanoacetamide according to claim 1, characterized in that: The molar ratio of the polysuccinimide to 4-aminophthalic acid is 1:(0.8-1.2).

4. A circulating water treatment agent containing dibromocyanoacetamide according to claim 1, characterized in that: The mass ratio of acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid, long-chain alkyl acrylate, allyl cyclodextrin, sodium dodecyl sulfonate and initiator is (15-30): (5-10): (0.5-2): (3-7): (0.8-2.5): (0.02-0.1).

5. A circulating water treatment agent containing dibromocyanoacetamide according to claim 1, characterized in that: The molecular weight of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-long-chain alkyl acrylate-allyl cyclodextrin copolymer is 2000-8000.

6. A circulating water treatment agent containing dibromocyanoacetamide according to claim 1, characterized in that: The initiators are ammonium persulfate and sodium bisulfite, and the molar ratio of ammonium persulfate to sodium bisulfite is 1:(1-1.5).

7. A method for preparing a circulating water treatment agent containing dibromocyanoacetamide according to any one of claims 1 to 6, characterized in that: The following steps are involved: Carboxymethyl cellulose graft copolymer, polyaspartic acid and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid-acrylic acid long-chain alkyl ester-allyl cyclodextrin copolymer are sequentially added into water, stirred and dissolved at 50-60°C, and then dibromocyanoacetamide and isothiazolinone are sequentially added and mixed and stirred to obtain a circulating water treatment agent containing dibromocyanoacetamide.

Images