Bactericide for circulating water and preparation method thereof

Abstract

The invention provides a bactericide for circulating water and a preparation method thereof, and belongs to the technical field of bactericides. The invention discloses a water-based cleaning agent which comprises the following components in percentage by weight: 50-70% of a bactericide and 30-50% of modified isothiazolinone, and the bactericide is prepared by compounding imidazole on the surface of UiO-66-NH2, coupling modified enzyme chelated with metal ions and then coating the surface with graphene oxide. The modified isothiazolinone is prepared by embedding an isothiazoline derivative, which is obtained by reacting 5-chloro-2-methyl-4-isothiazolin-3-one with borneol, and 2-methyl-4-isothiazolin-3-one into polyurea resin, and the modified isothiazolinone is prepared by embedding the isothiazoline derivative, which is obtained by reacting 5-chloro-2-methyl-4-isothiazolin-3-one with borneol, into the polyurea resin. The bactericide for the circulating water, prepared by the invention, has the advantages of safety, environmental protection, excellent antibacterial property, good stability, storage period as long as one year, convenience in use, reutilization after separation, reduction of the use cost, slow-release antibacterial effect, long-acting antibacterial effect and wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of fungicides, and particularly relates to a fungicide for circulating water and a preparation method thereof. Background Art

[0002] Circulating water mainly has two types: industrial and household, and the main purpose is to save water. Industrial circulating water is mainly used in cooling water systems, so it is also called circulating cooling water. Because industrial cooling water accounts for more than 90% of the total water consumption.

[0003] The environment in circulating water is conducive to the growth and reproduction of microorganisms. Since it has the three elements of sunlight, air, and water, due to the replenishment and concentration of nutrients, the increase in water temperature and long-term sunlight, it creates conditions for the rapid reproduction of bacteria and algae. A large amount of bacterial secretions cause floating dust impurities and chemical precipitates in the water to stick together, forming a sticky sediment, i.e., biological fouling, which adheres to the heat transfer surface of the main engine condenser and the heat exchange packing of the cooling tower. In addition to causing under-scale corrosion, it also reduces the flow rate of circulating water, lowers the heat exchange efficiency, increases power consumption and the load of the main engine, and may even block the pipeline severely.

[0004] Commonly used fungicides can be divided into two categories: oxidizing and non-oxidizing fungicides. Single-component fungicides have disadvantages such as large dosage, single variety, easy generation of drug resistance, and poor killing effect. And a compound formulation with a synergistic effect has a synergistic effect on each of the single components relative to it, can overcome the killing weaknesses of the single components, and can also reduce costs. The compounding is generally the compounding between non-oxidizing fungicides. The compounding principle is that after two or more fungicides are compounded, the comprehensive performance of the compound fungicide is better than that of each fungicide used alone, and there is a coordinated or complementary effect in performance.

[0005] Chinese Patent Application for Invention CN102726446A discloses a high-efficiency compound fungicide for a circulating water system. The raw material components and weight percentages of the high-efficiency compound fungicide are: glutaraldehyde 20%-30%, quaternary phosphonium salt 30%-40%, isothiazolinone 10%-20%, deionized water 20%-30%; wherein the quaternary phosphonium salt is tetrakis(hydroxymethyl)phosphonium sulfate or tetrakis(hydroxymethyl)phosphonium chloride or tetradecyltributylphosphonium chloride, and any one of the three can be selected. Chinese Patent for Invention CN101578997B discloses that the active ingredients of a compound fungicide are composed of the following types of non-oxidizing fungicides: tribenzylphenylphosphonium chloride (A), methylene bisthiocyanate (B), copper sulfate (C), and the recommended weight ratio of A, B, and C is 10-20∶10-35∶1. Chinese Patent for Invention CN1853468B discloses an aldehyde-based compound high-efficiency biocide, which is composed of 20%-40% of glutaraldehyde, 20%-40% of quaternary ammonium salt, and 5%-20% of an auxiliary agent. The quaternary ammonium salts selected in these patents cannot be used together with chlorophenol biocides and are not suitable for use with anionic surfactants. A large amount of Ca exists in the circulating water2+ , Mg 2+ , Al 3+ and Fe 2+ When metal ions such as Mg, Al, and Fe are present, the biocidal effect of quaternary ammonium salts will be reduced. Long-term use can easily cause microorganisms to develop drug resistance, increase the dosing concentration, increase the water treatment cost, and quaternary ammonium salts are prone to foaming and need to be used together with defoamers, which is not conducive to industrial production and is likely to cause environmental pollution.

[0006] Therefore, it is necessary to develop a highly efficient and safe bactericide for circulating water. Summary of the Invention

[0007] The purpose of the present invention is to provide a bactericide for circulating water and its preparation method, which is safe, environmentally friendly, has excellent antibacterial properties, good stability, a storage period of up to one year, is convenient to use, can be reused after separation, reduces the use cost, has a slow-release antibacterial effect, has a long-term antibacterial effect, and has broad application prospects.

[0008] The technical solution of the present invention is realized as follows:

[0009] The present invention provides a bactericide for circulating water, which consists of the following components in weight percentage: 50-70% of bactericide, 30-50% of modified isothiazolinone. The bactericide is a modified enzyme obtained by coupling and chelating metal ions after compounding imidazole on the surface of UiO-66-NH2, and then coating graphene oxide on the surface. The modified isothiazolinone is a modified isothiazolinone prepared by embedding an isothiazolin derivative obtained by reacting 5-chloro-2-methyl-4-isothiazolin-3-one with borneol and 2-methyl-4-isothiazolin-3-one in a polyurea resin.

[0010] As a further improvement of the present invention, the preparation method of the bactericide is as follows:

[0011] S1. Preparation of UiO-66-NH2: Add benzoic acid and 2-aminoterephthalic acid to N,N-dimethylformamide, add zirconium tetrachloride, carry out hydrothermal reaction, centrifuge, wash, and dry to obtain UiO-66-NH2;

[0012] S2. Preparation of modified enzyme chelating metal ions: Add caffeic acid to water, add EDC and NHS, stir and activate, add snail enzyme and lysozyme and mix evenly, stir and react, add copper salt and zinc salt, stir and chelate, dialyze, and freeze-dry to obtain modified enzyme chelating metal ions;

[0013] S3. Preparation of imidazole / UiO-66-NH2: Add imidazole-4-carboxylic acid to water, add EDC and NHS, stir and activate, add UiO-66-NH2, stir and react, centrifuge, wash, and dry to obtain imidazole / UiO-66-NH2;

[0014] S4. Preparation of Chelated Metal Ion-Modified Enzyme / Imidazole / UiO-66-NH2: Add the chelated metal ion-modified enzyme into water, add EDC and NHS, stir for activation, add imidazole / UiO-66-NH2 and stir for reaction, centrifuge, wash, and dry to obtain the chelated metal ion-modified enzyme / imidazole / UiO-66-NH2;

[0015] S5. Preparation of Fungicide: Add the chelated metal ion-modified enzyme / imidazole / UiO-66-NH2 into water, add graphene oxide, and perform freeze-drying to obtain the fungicide.

[0016] As a further improvement of the present invention, in step S1, the mass ratio of benzoic acid, 2-aminoterephthalic acid, and zirconium tetrachloride is 3-5:0.4-0.6:0.7-1, the temperature of the hydrothermal reaction is 120-140 °C, and the time is 20-24 h; in step S2, the mass ratio of caffeic acid, EDC, NHS, snail enzyme, lysozyme, copper salt, and zinc salt is 3-5:2-3:2-3:5-7:4-6:0.5-1:0.2-0.4, the copper salt is selected from at least one of copper chloride, copper sulfate, and copper nitrate, and the zinc salt is selected from at least one of zinc chloride, zinc sulfate, and zinc nitrate.

[0017] As a further improvement of the present invention, in step S3, the mass ratio of imidazole-4-carboxylic acid, EDC, NHS, and UiO-66-NH2 is 5-7:3-4:3-4:12-15; in step S4, the mass ratio of the chelated metal ion-modified enzyme, EDC, NHS, and imidazole / UiO-66-NH2 is 7-10:3-5:3-5:12-15.

[0018] As a further improvement of the present invention, in step S5, the mass ratio of the chelated metal ion-modified enzyme / imidazole / UiO-66-NH2 and graphene oxide is 8-10:3-5.

[0019] As a further improvement of the present invention, the preparation method of the modified isothiazolinone is as follows:

[0020] T1. Add 5-chloro-2-methyl-4-isothiazolin-3-one, natural borneol, and base into an organic solvent, heat and stir for reaction, remove the solvent under reduced pressure, perform recrystallization with acetone, filter, wash, and dry to obtain an isothiazolin derivative;

[0021] T2. Add a surfactant and polyvinyl alcohol into water to obtain an aqueous phase, add 2-methyl-4-isothiazolin-3-one and the isothiazolin derivative into xylene to obtain an oil phase;

[0022] T3. Add the oil phase dropwise into the water phase, emulsify, adjust the pH value, add urea, aqueous formaldehyde solution, ammonium chloride and resorcinol, heat and stir for reaction, centrifuge, wash and dry to obtain modified isothiazolinone.

[0023] As a further improvement of the present invention, the molar ratio of 5-chloro-2-methyl-4-isothiazolin-3-one, borneol and alkali in step T1 is 1:0.9 - 1:3 - 5. The organic solvent is selected from at least one of acetone, acetonitrile, chloroform and ethyl acetate. The temperature of the heating and stirring reaction is 55 - 60 °C and the time is 2 - 4 h. The alkali is selected from at least one of triethylamine, diethylamine, sodium hydroxide and potassium hydroxide.

[0024] As a further improvement of the present invention, the mass ratio of the surfactant, polyvinyl alcohol, 2-methyl-4-isothiazolin-3-one, isothiazolin derivative, urea, aqueous formaldehyde solution, ammonium chloride and resorcinol is 1 - 2:3 - 5:10 - 12:17 - 20:20 - 30:60 - 80:2 - 4:2 - 4. The surfactant is selected from at least one of sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium tetradecyl sulfonate, sodium tetradecyl benzene sulfonate, sodium tetradecyl sulfate, sodium hexadecyl sulfonate, sodium hexadecyl benzene sulfonate and sodium hexadecyl sulfate.

[0025] As a further improvement of the present invention, the pH value adjusted in step T3 is 8 - 9. The temperature of the heating and stirring reaction is 70 - 80 °C and the time is 3 - 5 h. The concentration of the aqueous formaldehyde solution is 36 - 38 wt%.

[0026] The present invention further protects a preparation method of the above-mentioned bactericide for circulating water, which includes the following steps: stir and mix the bactericide and the modified isothiazolinone evenly to obtain the bactericide for circulating water.

[0027] The present invention has the following beneficial effects:

[0028] Isothiazolinone is mainly composed of 5-chloro-2-methyl-4-isothiazolin-3-one (CIT) and 2-methyl-4-isothiazolin-3-one (MIT), which has a heterocyclic structure. Its bactericidal principle mainly relies on the active part on the heterocycle to destroy the DNA molecules in bacterial cells, rendering the bacteria inactive. However, direct use of isothiazolinone is irritating to the skin and eyes, may cause skin allergic reactions, and has certain toxicity. When the pH is greater than 8.5, the stability of isothiazolinone decreases, and it is particularly prone to degradation under alkaline conditions, with poor heat resistance. The temperature should not be higher than 40°C for a long time. When it comes into contact with strong oxidants or reductants, its anti-corrosion performance will decrease. In the present invention, 5-chloro-2-methyl-4-isothiazolin-3-one reacts with natural borneol, and the obtained coupling product not only improves the tolerance of 5-chloro-2-methyl-4-isothiazolin-3-one to temperature and pH, but also overcomes the drawback of easy sublimation of borneol. The antibacterial property of the prepared product is significantly improved. It is embedded with 2-methyl-4-isothiazolin-3-one to obtain a microcapsule structure, thereby being able to achieve the effect of slow release of isothiazolinone. At the same time, the stability is significantly improved, and its toxicity and sensitization are also significantly reduced.

[0029] The present invention prepares a bactericide using UiO-66 as a carrier, which has excellent specific surface area, good thermal stability and chemical stability, has a porous structure, can capture bacteria through physical adsorption, and cause damage to the cell membrane by direct contact with the bacterial cell membrane, thereby inhibiting bacterial growth. It is loaded with an imidazole structure with good antibacterial effect, and plays an antibacterial role by inhibiting the biosynthesis of ergosterol in the fungal cell membrane. It can interact with lipids and proteins in the fungal cell membrane, change the permeability and physiological functions of the cell membrane, and inhibit the normal physiological activities of cells, ultimately leading to cell death.

[0030] The present invention conducts a modification reaction on caffeic acid with snail enzyme and lysozyme to enhance the inhibitory ability of lysozyme against Gram-negative bacteria and the antibacterial activity of snail enzyme, and improve the stability of the enzyme. By chelating metal ions, copper ions and zinc ions play antibacterial roles by destroying cell membranes and ionic interactions, showing a synergistic effect.

[0031] The present invention loads the modified enzyme chelating metal ions on imidazole / UiO-66-NH2, greatly improving the stability of the enzyme and providing a rich site for the antibacterial reaction, thus contributing to improving the antibacterial performance. Coated with graphene oxide on the surface, on the one hand, it avoids the leakage and inactivation of the enzyme, improving the stability of the enzyme. On the other hand, graphene oxide plays an antibacterial role by physically destroying cell membranes, inducing oxidative stress and interfering with metabolic pathways, further improving the antibacterial performance.

[0032] The bactericide for circulating water prepared by the present invention is safe, environmentally friendly, has excellent antibacterial properties, good stability, a storage period of up to one year, is convenient to use, can be reused after separation, reduces the use cost, has a slow-release antibacterial effect and a long-lasting antibacterial effect, and has broad application prospects. Detailed implementation manners

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] NHS, N-hydroxysuccinimide; EDC, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride. Snailase, with a cell wall breaking rate of 90%; lysozyme, 2 million U / g.

[0035] Preparation Example 1 Preparation of bactericide

[0036] The method is as follows:

[0037] S1. Preparation of UiO-66-NH2: Add 3 g of benzoic acid and 0.4 g of 2-aminoterephthalic acid to 200 mL of N,N-dimethylformamide, add 0.7 g of zirconium tetrachloride, carry out a hydrothermal reaction at 120 °C for 20 h, centrifuge, wash, and dry to obtain UiO-66-NH2;

[0038] S2. Preparation of modified enzyme chelating metal ions: Add 3 g of caffeic acid to 200 mL of water, add 2 g of EDC and 2 g of NHS, stir and activate for 30 min, add 5 g of snailase and 4 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, add 0.5 g of copper chloride and 0.2 g of zinc chloride, stir and chelate for 30 min, dialyze, and freeze-dry to obtain a modified enzyme chelating metal ions;

[0039] S3. Preparation of imidazole / UiO-66-NH2: Add 5 g of imidazole-4-carboxylic acid to 200 mL of water, add 3 g of EDC and 3 g of NHS, stir and activate for 30 min, add 12 g of UiO-66-NH2, stir and react for 15 h, centrifuge, wash, and dry to obtain imidazole / UiO-66-NH2;

[0040] S4. Preparation of Chelated Metal Ion-Modified Enzyme / Imidazole / UiO-66-NH2: Add 7 g of chelated metal ion-modified enzyme to 200 mL of water, add 3 g of EDC and 3 g of NHS, stir and activate for 30 min, add 12 g of imidazole / UiO-66-NH2, stir and react for 10 h, centrifuge, wash, and dry to obtain chelated metal ion-modified enzyme / imidazole / UiO-66-NH2;

[0041] S5. Preparation of Fungicide: Add 8 g of chelated metal ion-modified enzyme / imidazole / UiO-66-NH2 to 200 mL of water, add 3 g of graphene oxide, and freeze-dry to obtain the fungicide.

[0042] Preparation Example 2 Preparation of Fungicide

[0043] The method is as follows:

[0044] S1. Preparation of UiO-66-NH2: Add 5 g of benzoic acid and 0.6 g of 2-aminoterephthalic acid to 200 mL of N,N-dimethylformamide, add 1 g of zirconium tetrachloride, carry out hydrothermal reaction at 140 °C for 24 h, centrifuge, wash, and dry to obtain UiO-66-NH2;

[0045] S2. Preparation of Chelated Metal Ion-Modified Enzyme: Add 5 g of caffeic acid to 200 mL of water, add 3 g of EDC and 3 g of NHS, stir and activate for 30 min, add 7 g of snail enzyme and 6 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, add 1 g of copper sulfate and 0.4 g of zinc sulfate, stir and chelate for 30 min, dialyze, and freeze-dry to obtain chelated metal ion-modified enzyme;

[0046] S3. Preparation of Imidazole / UiO-66-NH2: Add 7 g of imidazole-4-carboxylic acid to 200 mL of water, add 4 g of EDC and 4 g of NHS, stir and activate for 30 min, add 15 g of UiO-66-NH2, stir and react for 15 h, centrifuge, wash, and dry to obtain imidazole / UiO-66-NH2;

[0047] S4. Preparation of Chelated Metal Ion-Modified Enzyme / Imidazole / UiO-66-NH2: Add 10 g of chelated metal ion-modified enzyme to 200 mL of water, add 5 g of EDC and 5 g of NHS, stir and activate for 30 min, add 15 g of imidazole / UiO-66-NH2, stir and react for 10 h, centrifuge, wash, and dry to obtain chelated metal ion-modified enzyme / imidazole / UiO-66-NH2;

[0048] S5. Preparation of Fungicide: Add 10 g of chelated metal ion-modified enzyme / imidazole / UiO-66-NH2 to 200 mL of water, add 5 g of graphene oxide, and freeze-dry to obtain the fungicide.

[0049] Preparation Example 3 Preparation of Fungicide

[0050] The method is as follows:

[0051] S1. Preparation of UiO-66-NH2: Add 4 g of benzoic acid and 0.5 g of 2-aminoterephthalic acid to 200 mL of N,N-dimethylformamide, add 0.85 g of zirconium tetrachloride, and carry out a hydrothermal reaction at 130 °C for 22 h. Centrifuge, wash, and dry to obtain UiO-66-NH2;

[0052] S2. Preparation of modified enzyme chelating metal ions: Add 4 g of caffeic acid to 200 mL of water, add 2.5 g of EDC and 2.5 g of NHS, stir and activate for 30 min, add 6 g of snail enzyme and 5 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, add 0.7 g of copper nitrate and 0.3 g of zinc nitrate, stir and chelate for 30 min, dialyze, and freeze-dry to obtain the modified enzyme chelating metal ions;

[0053] S3. Preparation of imidazole / UiO-66-NH2: Add 6 g of imidazole-4-carboxylic acid to 200 mL of water, add 3.5 g of EDC and 3.5 g of NHS, stir and activate for 30 min, add 13 g of UiO-66-NH2, stir and react for 15 h, centrifuge, wash, and dry to obtain imidazole / UiO-66-NH2;

[0054] S4. Preparation of modified enzyme / imidazole / UiO-66-NH2 chelating metal ions: Add 8 g of the modified enzyme chelating metal ions to 200 mL of water, add 4 g of EDC and 4 g of NHS, stir and activate for 30 min, add 13 g of imidazole / UiO-66-NH2, stir and react for 10 h, centrifuge, wash, and dry to obtain the modified enzyme / imidazole / UiO-66-NH2 chelating metal ions;

[0055] S5. Preparation of fungicide: Add 9 g of the modified enzyme / imidazole / UiO-66-NH2 chelating metal ions to 200 mL of water, add 4 g of graphene oxide, and freeze-dry to obtain the fungicide.

[0056] Comparative Preparation Example 1

[0057] Compared with Example 3, the difference is that caffeic acid was not added in step S2.

[0058] Specifically as follows:

[0059] S2. Preparation of Chelated Metal Ion Composite Enzyme: Add 6 g of snail enzyme and 5 g of lysozyme into 200 mL of water, add 0.7 g of copper nitrate and 0.3 g of zinc nitrate, stir and chelate for 30 min, dialyze, and freeze-dry to obtain the chelated metal ion composite enzyme.

[0060] Comparative Preparation Example 2

[0061] Compared with Example 3, the difference lies in that copper nitrate was not added in step S2.

[0062] Specifically as follows:

[0063] S2. Preparation of Chelated Metal Ion Modified Enzyme: Add 4 g of caffeic acid into 200 mL of water, add 2.5 g of EDC and 2.5 g of NHS, stir and activate for 30 min, add 6 g of snail enzyme and 5 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, add 1 g of zinc nitrate, stir and chelate for 30 min, dialyze, and freeze-dry to obtain the chelated metal ion modified enzyme.

[0064] Comparative Preparation Example 3

[0065] Compared with Example 3, the difference lies in that zinc nitrate was not added in step S2.

[0066] Specifically as follows:

[0067] S2. Preparation of Chelated Metal Ion Modified Enzyme: Add 4 g of caffeic acid into 200 mL of water, add 2.5 g of EDC and 2.5 g of NHS, stir and activate for 30 min, add 6 g of snail enzyme and 5 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, add 1 g of copper nitrate, stir and chelate for 30 min, dialyze, and freeze-dry to obtain the chelated metal ion modified enzyme.

[0068] Comparative Preparation Example 4

[0069] Compared with Example 3, the difference lies in that neither copper nitrate nor zinc nitrate was added in step S2.

[0070] Specifically as follows:

[0071] S2. Preparation of Chelated Metal Ion Modified Enzyme: Add 4 g of caffeic acid into 200 mL of water, add 2.5 g of EDC and 2.5 g of NHS, stir and activate for 30 min, add 6 g of snail enzyme and 5 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, and freeze-dry to obtain the chelated metal ion modified enzyme.

[0072] Comparative Preparation Example 5

[0073] Compared with Example 3, the difference lies in that step S3 was not carried out.

[0074] The details are as follows:

[0075] S1. Preparation of UiO-66-NH2: Add 4 g of benzoic acid and 0.5 g of 2-aminoterephthalic acid into 200 mL of N,N-dimethylformamide, add 0.85 g of zirconium tetrachloride, carry out hydrothermal reaction at 130 °C for 22 h, centrifuge, wash, and dry to obtain UiO-66-NH2;

[0076] S2. Preparation of metal ion-chelated modified enzyme: Add 4 g of caffeic acid into 200 mL of water, add 2.5 g of EDC and 2.5 g of NHS, stir and activate for 30 min, add 6 g of snail enzyme and 5 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, add 0.7 g of copper nitrate and 0.3 g of zinc nitrate, stir and chelate for 30 min, dialyze, and freeze-dry to obtain the metal ion-chelated modified enzyme;

[0077] S3. Preparation of metal ion-chelated modified enzyme / UiO-66-NH2: Add 8 g of the metal ion-chelated modified enzyme into 200 mL of water, add 4 g of EDC and 4 g of NHS, stir and activate for 30 min, add 13 g of UiO-66-NH2, stir and react for 10 h, centrifuge, wash, and dry to obtain the metal ion-chelated modified enzyme / UiO-66-NH2;

[0078] S4. Preparation of fungicide: Add 9 g of the metal ion-chelated modified enzyme / UiO-66-NH2 into 200 mL of water, add 4 g of graphene oxide, and freeze-dry to obtain the fungicide.

[0079] Comparative Preparation Example 6

[0080] Compared with Example 3, the difference is that steps S2 and S4 are not carried out.

[0081] The details are as follows:

[0082] S1. Preparation of UiO-66-NH2: Add 4 g of benzoic acid and 0.5 g of 2-aminoterephthalic acid into 200 mL of N,N-dimethylformamide, add 0.85 g of zirconium tetrachloride, carry out hydrothermal reaction at 130 °C for 22 h, centrifuge, wash, and dry to obtain UiO-66-NH2;

[0083] S2. Preparation of imidazole / UiO-66-NH2: Add 6 g of imidazole-4-carboxylic acid into 200 mL of water, add 3.5 g of EDC and 3.5 g of NHS, stir and activate for 30 min, add 13 g of UiO-66-NH2, stir and react for 15 h, centrifuge, wash, and dry to obtain imidazole / UiO-66-NH2;

[0084] S3. Preparation of fungicide: Add 9 g of imidazole / UiO-66-NH2 to 200 mL of water, add 4 g of graphene oxide, and perform freeze-drying to obtain the fungicide.

[0085] Comparative Preparation Example 7

[0086] Compared with Example 3, the difference lies in that step S5 is not carried out.

[0087] Specifically as follows:

[0088] S1. Preparation of UiO-66-NH2: Add 4 g of benzoic acid and 0.5 g of 2-aminoterephthalic acid to 200 mL of N,N-dimethylformamide, add 0.85 g of zirconium tetrachloride, perform hydrothermal reaction at 130 °C for 22 h, centrifuge, wash, and dry to obtain UiO-66-NH2;

[0089] S2. Preparation of modified enzyme chelating metal ions: Add 4 g of caffeic acid to 200 mL of water, add 2.5 g of EDC and 2.5 g of NHS, stir and activate for 30 min, add 6 g of snail enzyme and 5 g of lysozyme, stir and mix for 15 min, stir and react for 12 h, add 0.7 g of copper nitrate and 0.3 g of zinc nitrate, stir and chelate for 30 min, perform dialysis, and perform freeze-drying to obtain the modified enzyme chelating metal ions;

[0090] S3. Preparation of imidazole / UiO-66-NH2: Add 6 g of imidazole-4-carboxylic acid to 200 mL of water, add 3.5 g of EDC and 3.5 g of NHS, stir and activate for 30 min, add 13 g of UiO-66-NH2, stir and react for 15 h, centrifuge, wash, and dry to obtain imidazole / UiO-66-NH2;

[0091] S4. Preparation of modified enzyme / imidazole / UiO-66-NH2 chelating metal ions: Add 8 g of the modified enzyme chelating metal ions to 200 mL of water, add 4 g of EDC and 4 g of NHS, stir and activate for 30 min, add 13 g of imidazole / UiO-66-NH2, stir and react for 10 h, centrifuge, wash, and dry to obtain the modified enzyme / imidazole / UiO-66-NH2 chelating metal ions, which is the fungicide.

[0092] Preparation of Modified Isothiazolinone in Preparation Example 4

[0093] The method is as follows:

[0094] T1. Add 10 mmol of 5-chloro-2-methyl-4-isothiazolin-3-one, 9 mmol of borneol, and 30 mmol of potassium hydroxide to 50 mL of ethyl acetate, heat to 55 °C, stir and react for 2 h, remove the solvent under reduced pressure, perform recrystallization with acetone, filter, wash, and dry to obtain the isothiazolin derivative;

[0095] T2. Add 0.1 g of sodium dodecylbenzenesulfonate and 0.3 g of polyvinyl alcohol to 200 mL of water to obtain the aqueous phase. Add 1 g of 2-methyl-4-isothiazolin-3-one and 1.7 g of isothiazoline derivative to 100 mL of xylene to obtain the oil phase;

[0096] T3. Drop the oil phase into the aqueous phase, emulsify at 8000 r / min for 15 min, adjust the pH value to 8, add 2 g of urea, 6 g of 36 wt% formaldehyde aqueous solution, 0.2 g of ammonium chloride and 0.2 g of resorcinol, heat to 70 °C, stir and react for 3 h, centrifuge, wash, and dry to obtain the modified isothiazolinone.

[0097] Preparation Example 5 Preparation of Modified Isothiazolinone

[0098] The method is as follows:

[0099] T1. Add 10 mmol of 5-chloro-2-methyl-4-isothiazolin-3-one, 10 mmol of borneol, and 50 mmol of sodium hydroxide to 50 mL of ethyl acetate, heat to 60 °C, stir and react for 4 h, remove the solvent under reduced pressure, recrystallize with acetone, filter, wash, and dry to obtain the isothiazoline derivative;

[0100] T2. Add 0.2 g of sodium dodecyl sulfate and 0.5 g of polyvinyl alcohol to 200 mL of water to obtain the aqueous phase. Add 1.2 g of 2-methyl-4-isothiazolin-3-one and 2 g of isothiazoline derivative to 100 mL of xylene to obtain the oil phase;

[0101] T3. Drop the oil phase into the aqueous phase, emulsify at 8000 r / min for 15 min, adjust the pH value to 9, add 3 g of urea, 8 g of 38 wt% formaldehyde aqueous solution, 0.4 g of ammonium chloride and 0.4 g of resorcinol, heat to 80 °C, stir and react for 5 h, centrifuge, wash, and dry to obtain the modified isothiazolinone.

[0102] Preparation Example 6 Preparation of Modified Isothiazolinone

[0103] The method is as follows:

[0104] T1. Add 10 mmol of 5-chloro-2-methyl-4-isothiazolin-3-one, 9.5 mmol of borneol, and 40 mmol of triethylamine to 50 mL of ethyl acetate, heat to 57 °C, stir and react for 3 h, remove the solvent under reduced pressure, recrystallize with acetone, filter, wash, and dry to obtain the isothiazoline derivative;

[0105] T2. Add 0.15 g of sodium dodecyl sulfonate and 0.4 g of polyvinyl alcohol to 200 mL of water to obtain an aqueous phase. Add 1.1 g of 2-methyl-4-isothiazolin-3-one and 1.85 g of isothiazoline derivative to 100 mL of xylene to obtain an oil phase;

[0106] T3. Drop the oil phase into the aqueous phase, emulsify at 8000 r / min for 15 min, adjust the pH value to 8.5, add 2.5 g of urea, 7 g of 37 wt% formaldehyde aqueous solution, 0.3 g of ammonium chloride and 0.3 g of resorcinol, heat to 75 °C, stir and react for 4 h, centrifuge, wash, and dry to obtain the modified isothiazolinone.

[0107] Comparative Preparation Example 8

[0108] Compared with Preparation Example 6, the difference is that step T1 is not carried out.

[0109] Specifically as follows:

[0110] T1. Add 0.15 g of sodium dodecyl sulfonate and 0.4 g of polyvinyl alcohol to 200 mL of water to obtain an aqueous phase. Add 1.1 g of 2-methyl-4-isothiazolin-3-one and 1.85 g of 5-chloro-2-methyl-4-isothiazolin-3-one to 100 mL of xylene to obtain an oil phase;

[0111] T2. Drop the oil phase into the aqueous phase, emulsify at 8000 r / min for 15 min, adjust the pH value to 8.5, add 2.5 g of urea, 7 g of 37 wt% formaldehyde aqueous solution, 0.3 g of ammonium chloride and 0.3 g of resorcinol, heat to 75 °C, stir and react for 4 h, centrifuge, wash, and dry to obtain the modified isothiazolinone.

[0112] Comparative Preparation Example 9

[0113] Compared with Preparation Example 6, the difference is that steps T2 and T3 are not carried out.

[0114] Specifically as follows:

[0115] T1. Add 10 mmol of 5-chloro-2-methyl-4-isothiazolin-3-one, 9.5 mmol of borneol, and 40 mmol of triethylamine to 50 mL of ethyl acetate, heat to 57 °C, stir and react for 3 h, remove the solvent under reduced pressure, recrystallize with acetone, filter, wash, and dry to obtain the isothiazoline derivative;

[0116] T2. Mix 1.1 g of 2-methyl-4-isothiazolin-3-one and 1.85 g of isothiazoline derivative for 10 min to obtain the modified isothiazolinone.

[0117] Example 1

[0118] This embodiment provides a bactericide for circulating water, which is composed of the following components by weight percentage: 50 - 70% of the bactericide prepared in Preparation Example 1, and 30 - 50% of the modified isothiazolinone prepared in Preparation Example 4.

[0119] The preparation method includes the following steps: Stir and mix the bactericide and the modified isothiazolinone for 10 minutes to obtain the bactericide for circulating water.

[0120] Example 2

[0121] This embodiment provides a bactericide for circulating water, which is composed of the following components by weight percentage: 50 - 70% of the bactericide prepared in Preparation Example 2, and 30 - 50% of the modified isothiazolinone prepared in Preparation Example 5.

[0122] The preparation method includes the following steps: Stir and mix the bactericide and the modified isothiazolinone for 10 minutes to obtain the bactericide for circulating water.

[0123] Example 3

[0124] This embodiment provides a bactericide for circulating water, which is composed of the following components by weight percentage: 50 - 70% of the bactericide prepared in Preparation Example 3, and 30 - 50% of the modified isothiazolinone prepared in Preparation Example 6.

[0125] The preparation method includes the following steps: Stir and mix the bactericide and the modified isothiazolinone for 10 minutes to obtain the bactericide for circulating water.

[0126] Comparative Example 1

[0127] Compared with Example 3, the difference is that the bactericide is prepared from Comparative Preparation Example 1.

[0128] Comparative Example 2

[0129] Compared with Example 3, the difference is that the bactericide is prepared from Comparative Preparation Example 2.

[0130] Comparative Example 3

[0131] Compared with Example 3, the difference is that the bactericide is prepared from Comparative Preparation Example 3.

[0132] Comparative Example 4

[0133] Compared with Example 3, the difference is that the bactericide is prepared from Comparative Preparation Example 4.

[0134] Comparative Example 5

[0135] Compared with Example 3, the difference is that the bactericide is prepared from Comparative Preparation Example 5.

[0136] Comparative Example 6

[0137] Compared with Example 3, the difference lies in that the fungicide is prepared from Comparative Preparation Example 6.

[0138] Comparative Example 7

[0139] Compared with Example 3, the difference lies in that the fungicide is prepared from Comparative Preparation Example 7.

[0140] Comparative Example 8

[0141] Compared with Example 3, the difference lies in that the modified isothiazolinone is prepared from Comparative Preparation Example 8.

[0142] Comparative Example 9

[0143] Compared with Example 3, the difference lies in that the modified isothiazolinone is prepared from Comparative Preparation Example 9.

[0144] Comparative Example 10

[0145] Compared with Example 3, the difference lies in that the modified isothiazolinone is not added.

[0146] Test Example 1

[0147] Add a fungicide for circulating water to the water sample at a concentration of 10 ppm. After contacting at room temperature for a certain period of time, according to the analysis method specified for industrial circulating cooling water, the number of residual heterotrophic bacteria is measured by the plate counting method. At the same time, a blank sample is made and compared with the bacteria content of the original water sample to obtain the bactericidal rate. The results are shown in Table 1.

[0148] Table 1

[0149]

[0150] As can be seen from the above table, the fungicides for circulating water prepared in Examples 1-3 of the present invention have good long-term bactericidal effects. As time goes by, the fungicides are consumed, and the residual bacteria should have reproduced and grown again. However, the fungicides for circulating water of the present invention can still maintain a high bactericidal rate, indicating that they have the effects of slow release and extended bactericidal action.

[0151] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bactericide for circulating water, characterized in that: The invention comprises the following components in weight percentage: 50-70% of a fungicide and 30-50% of a modified isothiazolinone, wherein the fungicide is prepared by compounding imidazole on the surface of UiO-66-NH2, coupling a modified enzyme for chelating metal ions, and then coating the surface with graphene oxide, and the modified isothiazolinone is prepared by embedding an isothiazolinone derivative obtained by reacting 5-chloro-2-methyl-4-isothiazoline-3-one with borneol and 2-methyl-4-isothiazoline-3-one in a polyurea resin.

2. The bactericide for circulating water according to claim 1, characterized in that: The preparation method of the bactericide is as follows: S1. Preparation of UiO-66-NH2: Add benzoic acid and 2-aminoterephthalic acid to N,N-dimethylformamide, add zirconium tetrachloride, perform hydrothermal reaction, centrifuge, wash, and dry to obtain UiO-66-NH2; S2. Preparation of modified enzymes for chelating metal ions: adding caffeic acid to water, adding EDC and NHS, stirring to activate, adding snail enzyme and lysozyme to mix evenly, stirring to react, adding copper salt and zinc salt, stirring to chelate, dialyzing, freeze-drying, and obtaining modified enzymes for chelating metal ions; S3. Preparation of imidazole / UiO-66-NH2: Add imidazole-4-carboxylic acid to water, add EDC and NHS, stir to activate, add UiO-66-NH2, stir to react, centrifuge, wash, and dry to obtain imidazole / UiO-66-NH2; S4. Preparation of modified enzyme / imidazole / UiO-66-NH2 for chelating metal ions: adding the modified enzyme for chelating metal ions to water, adding EDC and NHS, stirring for activation, adding imidazole / UiO-66-NH2, stirring for reaction, centrifuging, washing, and drying to obtain modified enzyme / imidazole / UiO-66-NH2 for chelating metal ions; S5. Preparation of fungicide: adding modified enzyme / imidazole / UiO-66-NH2 chelating metal ions into water, adding graphene oxide, and freeze-drying to obtain a fungicide.

3. The bactericide for circulating water according to claim 2, characterized in that: The mass ratio of benzoic acid, 2-aminoterephthalic acid and zirconium tetrachloride in step S1 is 3-5: 0.4-0.6: 0.7-1, the temperature of the hydrothermal reaction is 120-140° C., and the time is 20-24 hours; the mass ratio of caffeic acid, EDC, NHS, snail enzyme, lysozyme, copper salt and zinc salt in step S2 is 3-5: 2-3: 2-3: 5-7: 4-6: 0.5-1: 0.2-0.4, the copper salt is selected from at least one of copper chloride, copper sulfate and copper nitrate, and the zinc salt is selected from at least one of zinc chloride, zinc sulfate and zinc nitrate.

4. The bactericide for circulating water according to claim 2, characterized in that: The mass ratio of imidazole-4-carboxylic acid, EDC, NHS and UiO-66-NH2 in step S3 is 5-7:3-4:3-4:12-15; the mass ratio of the modified enzyme for chelating metal ions, EDC, NHS and imidazole / UiO-66-NH2 in step S4 is 7-10:3-5:3-5:12-15.

5. The bactericide for circulating water according to claim 2, characterized in that: The mass ratio of the modified enzyme for chelating metal ions / imidazole / UiO-66-NH2 and graphene oxide in step S5 is 8-10:3-5.

6. The bactericide for circulating water according to claim 1, characterized in that: The preparation method of the modified isothiazolinone is as follows: T1. Add 5-chloro-2-methyl-4-isothiazoline-3-one, natural borneol and base to an organic solvent, heat and stir to react, remove the solvent under reduced pressure, recrystallize from acetone, filter, wash and dry to obtain an isothiazolinone derivative; T2. Adding a surfactant and polyvinyl alcohol to water to obtain an aqueous phase, adding 2-methyl-4-isothiazoline-3-one and an isothiazolinone derivative to xylene to obtain an oil phase; T3. Add the oil phase dropwise into the water phase, emulsify, adjust the pH value, add urea, formaldehyde aqueous solution, ammonium chloride and resorcinol, heat and stir to react, centrifuge, wash and dry to obtain modified isothiazolinone.

7. The bactericide for circulating water according to claim 6, characterized in that: In step T1, the molar ratio of 5-chloro-2-methyl-4-isothiazoline-3-one, natural borneol and base is 1:0.9-1:3-5, the organic solvent is selected from at least one of acetone, acetonitrile, chloroform and ethyl acetate, the temperature of the heating and stirring reaction is 55-60°C, the time is 2-4h, and the base is selected from at least one of triethylamine, diethylamine, sodium hydroxide and potassium hydroxide.

8. The bactericide for circulating water according to claim 6, characterized in that: The mass ratio of the surfactant, polyvinyl alcohol, 2-methyl-4-isothiazoline-3-one, isothiazolinone derivative, urea, formaldehyde aqueous solution, ammonium chloride and resorcinol is 1-2:3-5:10-12:17-20:20-30:60-80:2-4:2-4, and the surfactant is selected from at least one of sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium tetradecyl sulfonate, sodium tetradecylbenzene sulfonate, sodium tetradecyl sulfate, sodium hexadecyl sulfonate, sodium hexadecylbenzene sulfonate and sodium hexadecyl sulfate.

9. The bactericide for circulating water according to claim 6, characterized in that: In step T3, the pH value is adjusted to 8-9, the temperature of the heating and stirring reaction is 70-80° C., the time is 3-5 hours, and the concentration of the formaldehyde aqueous solution is 36-38 wt %.

10. A method for preparing a bactericide for circulating water according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: stirring and mixing the bactericide and the modified isothiazolinone evenly to obtain the bactericide for circulating water.

Images