Preparation method of water treatment agent and water treatment agent

Abstract

The invention provides a preparation method of a water treatment agent, which comprises the following steps: providing polysuccinimide, amino acid and inorganic base, mixing according to a ratio, adding a solvent, and reacting to obtain a mixture A; and then adjusting the pH value of the mixture A to weak acidity, adding isothiazolinone, and uniformly mixing to obtain the water treatment agent. The invention further provides the water treatment agent prepared by the method, and the agent has scale inhibition and sterilization performance at the same time.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, and particularly relates to a water treatment agent and its preparation method. Background Technology

[0002] In industrial production in industries such as chemical, pharmaceutical, and metallurgy, large equipment often generates a large amount of heat, which needs to be removed in time to avoid dangerous accidents. Water cooling is the most widely used cooling method.

[0003] However, during operation, cooling water is often recycled for water conservation and economic reasons. Therefore, during production, water easily forms scale on equipment surfaces, and this scale often contains large amounts of corrosive impurities such as chlorine and sulfur, causing corrosion. Furthermore, bacteria can easily grow in the scale, posing a risk of further corrosion and damage to the equipment.

[0004] Therefore, in industrial production, large quantities of agents such as scale inhibitors, corrosion inhibitors, flocculants, pre-filming agents, or bactericides are often used to treat circulating cooling water to ensure water quality. However, the use of large quantities of agents can also cause unavoidable pollution to the aquatic environment, economic waste, and complex processes. Summary of the Invention

[0005] This disclosure provides a compound water treatment agent that simultaneously possesses scale inhibition and bactericidal properties, which can effectively improve the efficiency of the circulating cooling water treatment process.

[0006] According to one aspect of this disclosure, a method for preparing a water treatment agent is provided, comprising the following steps:

[0007] S01: Polysuccinimide, amino acids and inorganic bases are provided, mixed in proportion and added to water to react and obtain mixture A;

[0008] S02: Adjust the pH of mixture A to weakly acidic, add isothiazolinone and mix well to obtain a water treatment agent.

[0009] In one feasible manner, the inorganic base may be selected from at least one of sodium hydroxide and potassium hydroxide.

[0010] The disclosed water treatment agent is a water treatment agent with dual effects of scale inhibition and bactericidal action. In the above preparation process, polysuccinimide first undergoes ring-opening under alkaline conditions to obtain a main chain structure similar to a polyaspartic acid derivative, and then undergoes ammonolysis with amino acids to obtain a grafted product, as shown in Formula 1 below:

[0011]

[0012] Agents containing this grafted product exhibit excellent scale inhibition capabilities. Both the main chain and branches of the agent contain carboxylic acid groups, which effectively chelate free calcium, magnesium, and iron ions in water, thus achieving scale inhibition. Furthermore, the amide groups generated in the agent possess both bactericidal effects and further enhance its scale inhibition performance, resulting in superior overall performance.

[0013] In one feasible embodiment, the mass ratio of polysuccinimide to inorganic base is 2:1 to 6:1, or the mass ratio of polysuccinimide to inorganic base is 5:1 to 6:1.

[0014] In one feasible manner, the amino acid is selected from at least one of glutamic acid, methionine, cysteine, arginine, and histidine.

[0015] In one feasible embodiment, the mass ratio of polysuccinimide to amino acids is 3:1-10:1, or 3.3:1-10:1, or 5:1-10:1, or the mass ratio of polysuccinimide to amino acids is 6:1-10:1.

[0016] In one feasible manner, the total mass ratio of polysuccinimide, amino acids, and inorganic base to water is 1:2-1:10, or 1:2-1:8, or 1:3-1:6, or 1:2-1:5.

[0017] In one feasible embodiment, in step S01, the reaction temperature is 40℃-80℃, or the reaction temperature is 40℃-60℃; the reaction time is 4h-10h, or the reaction time is 6h-8h. Typically, the above reaction is carried out under stirring, with a stirring speed of 100rpm-500rpm, or 100rpm-300rpm, for a stirring time of 4h-10h.

[0018] In step S02, the pH of mixture A is adjusted to a weakly acidic state, and then isothiazolinone is added and mixed thoroughly to obtain a water treatment agent. Isothiazolinone is a bactericide whose bactericidal ability mainly comes from the N-S base on the nitrogen heterocycle. This base can form hydrogen bonds with proteins within bacterial cells, adsorb onto them, and further undergo a substitution ring-opening reaction to destroy the protein structure, preventing normal cell metabolism and thus achieving the purpose of sterilization. Experiments have shown that isothiazolinone cannot be stored for long under alkaline conditions. Therefore, the solution is first adjusted to a weakly acidic state before adding isothiazolinone for further compounding to obtain a water treatment agent with enhanced bactericidal ability. Adjusting the pH of mixture A to a weakly acidic state means adjusting it to between 7 and 5. If the pH is higher than 7, isothiazolinone is difficult to maintain in an alkaline environment and is easily decomposed. A pH lower than 5 will result in waste of the adjusting agent.

[0019] In one feasible manner, the total mass ratio of polysuccinimide, amino acids, and inorganic base to isothiazolinone is 10:1-20:1, or 10:1-16:1, or 13:1-20:1.

[0020] Another aspect of this disclosure provides a water treatment agent prepared using the method described above. Detailed Implementation

[0021] The technical solutions of this disclosure will be clearly and thoroughly described below with reference to some embodiments. The following description of at least one exemplary embodiment is merely illustrative and is not intended to limit this disclosure or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0022] Example 1:

[0023] Take a 250ml three-necked glass flask, add 10g of polysuccinimide, 3g of glutamic acid, and 5g of sodium hydroxide sequentially, then pour in 100ml of pure water. Mix well and reflux at 200rpm in an 80℃ water bath for 8 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 0.8g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0024] Example 2:

[0025] Take a 250ml three-necked glass flask, add 10g of polysuccinimide, 1g of methionine, and 3.2g of sodium hydroxide sequentially, then pour in 140ml of pure water. Mix well and reflux at 300rpm in a 60℃ water bath for 6 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, and add 1.4g of isothiazolinone. Mix well to obtain the desired water treatment agent.

[0026] Example 3:

[0027] Take a 250ml three-necked glass flask, add 15g of polysuccinimide, 1.4g of cysteine, and 2.5g of sodium hydroxide sequentially, then pour in 100ml of pure water. Mix well and reflux at 100rpm in a 60℃ water bath for 4 hours with stirring. After the reaction is complete, adjust the pH to 6.0-7.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 1g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0028] Example 4:

[0029] Take a 250ml three-necked glass flask, add 20g of polysuccinimide, 5g of glutamic acid, and 8g of sodium hydroxide sequentially, then pour in 100ml of pure water. Mix well and reflux at 500rpm in an 80℃ water bath for 10 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 2g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0030] Example 5:

[0031] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 5g of arginine, and 5g of sodium hydroxide sequentially, then pour in 80ml of pure water. Mix well and reflux at 200rpm in a 40℃ water bath for 10 hours with stirring. After the reaction is complete, adjust the pH to 6.0-7.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 2g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0032] Example 6:

[0033] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 3g of glutamic acid, and 5g of sodium hydroxide sequentially, then pour in 110ml of pure water. Mix well and reflux at 200rpm in a 60℃ water bath for 8 hours with stirring. After the reaction is complete, adjust the pH to 6.0-7.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 2.4g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0034] Example 7:

[0035] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 4.8g of glutamic acid, and 6g of sodium hydroxide sequentially, then pour in 120ml of pure water. Mix well and reflux at 100rpm in a 60℃ water bath for 6 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 3g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0036] Example 8:

[0037] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 3g of histidine, and 10g of sodium hydroxide sequentially, then pour in 90ml of pure water. Mix well and reflux at 150rpm in a 60℃ water bath for 6 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, and add 4.3g of isothiazolinone. Mix well to obtain the desired water treatment agent.

[0038] Example 9:

[0039] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 3g of glutamic acid, and 10g of sodium hydroxide sequentially, then pour in 110ml of pure water. Mix well and reflux at 150rpm in a 60℃ water bath for 8 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 3g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0040] Example 10:

[0041] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 3g of glutamic acid, and 10g of sodium hydroxide sequentially, then pour in 110ml of pure water. Mix well and reflux at 150rpm in a 60℃ water bath for 8 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, and add 4.3g of isothiazolinone. Mix well to obtain the desired water treatment agent.

[0042] Example 11:

[0043] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 3g of glutamic acid, and 10g of sodium hydroxide sequentially, then pour in 110ml of pure water. Mix well and reflux at 150rpm in a 60℃ water bath for 8 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 3.5g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0044] Example 12:

[0045] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 3g of glutamic acid, and 10g of sodium hydroxide sequentially, then pour in 110ml of pure water. Mix well and reflux at 150rpm in a 60℃ water bath for 8 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 2.7g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0046] Example 13:

[0047] Take a 250ml three-necked glass flask, add 30g of polysuccinimide, 3g of glutamic acid, and 10g of sodium hydroxide sequentially, then pour in 110ml of pure water. Mix well and reflux at 150rpm in a 60℃ water bath for 8 hours with stirring. After the reaction is complete, adjust the pH to 5.0-6.0 with dilute hydrochloric acid solution, then remove the flask, cool to room temperature, add 2.5g of isothiazolinone, mix well, and the desired water treatment agent is obtained.

[0048] The products of each experimental example were tested according to the standard GB / T16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". The test temperature was 80℃, the test time was 10 hours, and the agent concentration in the water was 5 ppm. The test results are as follows:

[0049] Table 1

[0050]

[0051] The products of each experimental example were tested according to the standard "DL / T 1116-2009 Performance Evaluation of Bactericides for Circulating Cooling Water". The incubation temperature was 37℃, the incubation time was 24h, and the concentration of the agent in the water sample was 20ppm. The test results are as follows:

[0052] Table 2

[0053]

[0054] As can be seen from the test data in Tables 1 and 2, the scale inhibition rates of the water treatment agents obtained in Examples 1-9 are between 28% and 39%, indicating good scale inhibition effects. The bactericidal rates of the water treatment agents obtained in Examples 9-13 are all above 86%. When the mass ratio of isothiazolinone to the total mass of polysuccinimide, amino acids, and inorganic base in mixture A is greater than 1:14.3, the bactericidal rate reaches 100%, demonstrating excellent bactericidal performance.

Claims

1. A method for preparing a water treatment agent, comprising: S01: Polysuccinimide, amino acids and inorganic bases are provided, mixed in proportion and added to water to react and obtain mixture A; S02: Adjust the pH of mixture A to weakly acidic, then add isothiazolinone and mix to obtain a water treatment agent.

2. The method for preparing a water treatment agent according to claim 1, characterized in that, The inorganic base is selected from at least one of sodium hydroxide and potassium hydroxide.

3. The method for preparing a water treatment agent according to claim 2, characterized in that, The mass ratio of polysuccinimide to inorganic base is 2:1-6:

1.

4. The method for preparing a water treatment agent according to claim 1, characterized in that, The amino acid is selected from at least one of glutamic acid, methionine, cysteine, arginine, and histidine.

5. The method for preparing a water treatment agent according to claim 4, characterized in that, The mass ratio of polysuccinimide to amino acids is 3:1-10:

1.

6. The method for preparing a water treatment agent according to claim 1, characterized in that, The total mass ratio of polysuccinimide, amino acids, and inorganic base to water is 1:2 to 1:

10.

7. The method for preparing a water treatment agent according to claim 1, characterized in that, In S01, the reaction temperature is 40℃-80℃.

8. The method for preparing a water treatment agent according to claim 1, characterized in that, The total mass ratio of polysuccinimide, amino acids, and inorganic base to isothiazolinone is 10:1-20:

1.

9. The method for preparing a water treatment agent according to claim 1, characterized in that, Adjusting the pH of mixture A to a slightly acidic level means adjusting the pH to between 7 and 5.

10. A water treatment agent, prepared by the preparation method according to any one of claims 1-9.

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