A high-efficiency water treatment scale inhibitor and its preparation method and application

Abstract

The present invention belongs to the field of water treatment technology, and discloses a high-efficiency water treatment scale inhibitor, its preparation method and application. The high-efficiency water treatment scale inhibitor of the present invention comprises the following raw materials in percentage by mass: polyacrylic acid 15-30%, 1-hydroxyethylidene-1,1-diphosphonic acid 5-15%, sodium hexametaphosphate 1-5%, sodium sulfate 0.5-1%, hydrolyzed polymaleic anhydride 3-8%, ethylenediaminetetramethylenephosphonic acid 2-10%, super chelating agent 0.3-1.5%, and the balance is water, wherein the super chelating agent is a copolymer of 2,2',2''-triethyl aminotriacetate and an ethylene glycol-based polymer. The high-efficiency water treatment scale inhibitor of the present invention not only has a sustained chelating ability, but also has excellent stability. It can still exert an efficient scale inhibition effect under complex and extreme conditions such as high temperature and high hardness water, showing significant advantages.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and in particular relates to a high-efficiency water treatment scale inhibitor and a preparation method and application thereof. Background Art

[0002] Scale formation is a major problem in industrial water treatment systems. Especially under high-temperature, high-hardness water conditions, deposits such as calcium carbonate, calcium sulfate, and silicates gradually accumulate in pipes, heat exchangers, and boilers, leading to reduced heat transfer efficiency, increased energy consumption, and even equipment failure or downtime for maintenance. To address this issue, scale inhibitors are often added to control water quality.

[0003] Scale inhibitors currently on the market primarily rely on chemical substances such as organophosphates and polymers. These inhibitors slow scale formation through chelation, crystal growth inhibition, and dispersion. However, these common inhibitors suffer from instability and reduced efficiency under certain extreme conditions (such as high temperatures and high water hardness): 1) Decomposition and failure at high temperatures: Many scale inhibitors, especially polyacrylic acid inhibitors, are susceptible to decomposition at high temperatures. As the temperature rises, their scale inhibition effectiveness significantly decreases, making it difficult to effectively control scale problems. 2) Limitations in high-hardness water: High-hardness water contains large amounts of metal ions such as calcium and magnesium. The chelation effect of traditional scale inhibitors is often unable to completely prevent the precipitation of metal ions, leading to rapid scale formation. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies in the existing technology and provide a high-efficiency water treatment scale inhibitor and its preparation method and application. The scale inhibitor not only has continuous chelating ability, but also has excellent stability. It can still exert a high-efficiency scale inhibition effect under complex and extreme conditions such as high temperature and high hardness water, showing significant advantages.

[0005] To solve the technical problem raised by the present invention, the present invention provides a high-efficiency water treatment scale inhibitor, comprising the following raw materials in percentage by weight: 15-30% polyacrylic acid, 5-15% 1-hydroxyethylidene-1,1-diphosphonic acid, 1-5% sodium hexametaphosphate, 0.5-1% sodium sulfate, 3-8% hydrolyzed polymaleic anhydride, 2-10% ethylenediaminetetramethylenephosphonic acid, 0.3-1.5% super chelating agent, and the balance being water.

[0006] In the above scheme, the super chelating agent is a copolymer of triethyl 2,2',2''-aminotriacetate and ethylene glycol-based polymer, the main chemical components of which are (C 12 H 18 N2O4) n , the degree of polymerization is 5000~10000.

[0007] In the above scheme, the preparation method of the super chelating agent comprises the following steps:

[0008] 1) dissolving triethyl 2,2',2''-aminotriacetate in a polar solvent, and then adding a hydrolyzing agent to obtain a mixed solution;

[0009] 2) After heating the mixed solution to the polymerization temperature, slowly adding the ethylene glycol-based polymer and the polymerization catalyst thereto to carry out a polymerization reaction;

[0010] 3) After the polymerization reaction is completed, a dilute acid solution is added to terminate the reaction and precipitate the copolymer in the system. The copolymer is washed and dried to obtain a solid super chelating agent.

[0011] Furthermore, the polar solvent is one of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0012] Furthermore, the mass ratio of the triethyl 2,2',2''-aminotriacetate to the volume ratio of the polar solvent is 1 g: (25-50) mL, so as to ensure that the reactants have sufficient dispersion in the solution.

[0013] Furthermore, the hydrolyzing agent is one of sodium hydroxide and potassium hydroxide.

[0014] Furthermore, the hydrolyzing agent is prepared into an aqueous solution with a concentration of 0.5-1 mol / L and then added.

[0015] Furthermore, the mass ratio of the hydrolyzing agent to triethyl 2,2',2''-aminotriacetate is (1.5-2):1.

[0016] Furthermore, the polymerization temperature is 70-90°C.

[0017] Furthermore, the total polymerization reaction time is 2 to 3 hours, wherein the ethylene glycol-based polymer and the polymerization catalyst are added for 0.5 to 1 hour, and the reaction is continued for 1.5 to 2 hours after the addition is completed.

[0018] Furthermore, the ethylene glycol-based polymer is one of polyethylene glycol and polyethylene glycol diacrylate, which can provide appropriate reaction sites and enhance the flexibility of the copolymer.

[0019] Furthermore, the mass ratio of the ethylene glycol-based polymer to triethyl 2,2',2''-aminotriacetate is (2-5):1.

[0020] Furthermore, the polymerization catalyst is a copper-based MOF material.

[0021] Furthermore, the polymerization catalyst is one of Cu-BTC, Cu-MOF-74, and Cu-TPA.

[0022] Furthermore, the mass ratio of the polymerization catalyst to triethyl 2,2',2''-aminotriacetate is (0.01-0.05):1, ensuring that the reaction is promoted at an appropriate amount without affecting the properties of the copolymer.

[0023] Furthermore, the dilute acid solution is hydrochloric acid or sulfuric acid, with a concentration of 0.1-0.5 mol / L.

[0024] Furthermore, the mass of the dilute acid solution is 1 to 1.5 times the total mass of the polymerization reaction system.

[0025] Furthermore, the washing is performed using ethanol, methanol or water to remove unreacted monomers and solvent residues.

[0026] Furthermore, the drying temperature is 50-80° C. and the drying time is 4-8 hours.

[0027] The present invention also provides a method for preparing a high-efficiency water treatment scale inhibitor, comprising the following steps:

[0028] S1. Add polyacrylic acid, sodium sulfate, 1-hydroxyethylidene-1,1-diphosphonic acid, sodium hexametaphosphate and hydrolyzed polymaleic anhydride to water in sequence and stir thoroughly until dissolved;

[0029] S2. After the temperature is raised, EDTA and the super chelating agent are added successively, and stirring is continued to ensure that the components are evenly mixed and stable;

[0030] S3. After cooling to room temperature, filter to obtain a clarified high-efficiency water treatment antiscalant.

[0031] In the above scheme, in step S2, the temperature is raised to 50-60°C. This temperature range can ensure good solubility and uniform dispersion of EDTA and the super chelating agent while avoiding decomposition that may be caused by excessively high temperatures.

[0032] The present invention also provides an application of a high-efficiency water treatment scale inhibitor in water treatment, and the application method is: adding the high-efficiency water treatment scale inhibitor to a water system requiring scale inhibition.

[0033] In the above solution, the high-efficiency water treatment scale inhibitor can be quantitatively added through a dosing pump so that the scale inhibitor is stably present in the water system and effectively acts.

[0034] In the above solution, the dosage of the high-efficiency water treatment scale inhibitor is 10-50 mg / L. This concentration range can effectively exert the scale inhibition effect while avoiding the economic cost increase and side effects caused by excessive use.

[0035] In the above scheme, the temperature applicable range of the high-efficiency water treatment scale inhibitor is 20~90°C, and the hardness applicable range is 100~1000mg / L in terms of CaCO3.

[0036] The technical concept of the present invention is:

[0037] First, a super chelating agent is prepared. 2,2',2''-aminotriacetic acid triethyl ester is used as the basic structure of the chelating agent to provide nitrogen atoms for metal chelation. Ethylene glycol polymer is used to form superconducting channels between molecules to ensure the flexibility and conductivity of the molecular chain structure. A polymerization catalyst is used to start the polymerization process of the molecules. Its molecular skeleton is composed of repeated nitrogen-oxygen groups. These groups provide chelating sites through nitrogen atoms. Nitrogen atoms bind to metal ions (such as Ca) through coordination bonds. 2 + Mg 2+ ) combination, while oxygen atoms provide additional electron cloud effects to help stabilize this combination and prevent metal ion scaling, and have a synergistic mechanism in chelating and stabilizing metal ions; its molecular structure can maintain chemical stability at higher temperatures and is conducive to the efficient conduction and dispersion of metal ions, ensuring excellent stability and chelation in high temperature and complex water quality.

[0038] Secondly, the super chelating agent is made into a high-efficiency water treatment scale inhibitor with other components. The components have a synergistic promoting effect, as follows:

[0039] Dispersing Effects of Polyacrylic Acid and Hydrolyzed Polymaleic Anhydride: Both polyacrylic acid and hydrolyzed polymaleic anhydride disperse particles, but their mechanisms of action differ. Polyacrylic acid primarily prevents calcium ions from binding to carbonates, while hydrolyzed polymaleic anhydride inhibits crystal growth by binding to metal ions via carboxyl groups. The synergistic effect of these two agents not only inhibits initial crystal formation but also prevents the aggregation of already formed small crystals, thereby forming a stable dispersion system and effectively preventing large-scale scale deposition.

[0040] Chelation of 1-Hydroxyethylidene-1,1-diphosphonate and EDTA (Methylenediamine Phosphonic Acid): Both 1-Hydroxyethylidene-1,1-diphosphonate and EDTA (Methylenediamine Phosphonic Acid) possess the ability to chelate metal ions, but their effectiveness varies depending on water quality. 1-Hydroxyethylidene-1,1-diphosphonate is highly effective in low to moderate water hardness, while EDTA (Methylenediamine Phosphonic Acid) maintains high chelation efficiency in high-hardness water. This combination ensures that the scale inhibitor effectively inhibits the precipitation of metal ions such as calcium and magnesium under a wide range of water conditions, maintaining its effectiveness even in high-hardness conditions, forming a powerful chelation system.

[0041] The crystal growth inhibition and dispersing effects of super chelating agents and sodium hexametaphosphate: Super chelating agents, through their unique molecular framework and chelation, effectively bind metal ions like calcium and magnesium at high temperatures, preventing scale formation. The multivalent phosphates in sodium hexametaphosphate inhibit crystal growth and aggregation. The combined effect further enhances the stability and effectiveness of the scale inhibitor under high-temperature and high-hardness conditions. This combination is particularly suitable for forming a robust scale-inhibiting protective layer in systems subject to large temperature fluctuations.

[0042] Sodium sulfate's supporting role: As an ionic strength regulator, sodium sulfate helps maintain solution uniformity throughout the formulation, ensuring a more uniform chelation and dispersion of other ingredients. By providing higher ionic strength, it not only enhances the chelating agent's attraction to metal ions but also helps dispersed ingredients remain dispersed, further improving the stability and long-term effectiveness of the scale inhibitor.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention aims to solve the problems of insufficient stability and decreased efficiency of existing scale inhibitors under extreme water conditions such as high temperature and high hardness, and develops a new and efficient water treatment scale inhibitor. The super chelating agent in its composition can effectively chelate metal ions such as calcium and magnesium under high temperature environment to prevent the formation of sediment. At the same time, the hydrolyzed polymaleic anhydride provides additional dispersing effect in high temperature environment through its carboxyl structure to prevent the aggregation of precipitated crystals, so that the scale inhibitor can maintain chemical stability and continuously disperse sediments in high temperature environment to avoid the formation of scale. In addition, the auxiliary effect of polyacrylic acid, the dispersing ability of polyacrylic acid under high temperature conditions and the chelating ability of LGF work together to further inhibit the formation of calcium carbonate and other sediments. This multi-level dispersion and chelation synergistic effect significantly improves the scale inhibitor in high temperature water. Stability and scale inhibition efficiency under high hardness conditions; for high hardness water conditions, super chelating agent and 1-hydroxyethyl-1,1-diphosphonate chelate metal ions from different sites respectively, reducing the tendency of metal ions to combine with carbonate and sulfate, and the dual chelation ensures that the formation of scale can still be effectively controlled under high hardness conditions. At the same time, the polyvalent phosphate of sodium hexametaphosphate combines with metal ions such as calcium and magnesium to further inhibit the formation of crystals, and complements the chelation effect of super chelating agent and 1-hydroxyethyl-1,1-diphosphonate. Under high hardness conditions, it achieves a more efficient scale inhibition effect than a single ingredient by simultaneously dispersing, chelating and inhibiting crystallization. In summary, the scale inhibitor of the present invention can still achieve efficient scale inhibition under complex and extreme conditions such as high temperature and high hardness water, showing significant advantages. DETAILED DESCRIPTION

[0045] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

[0046] Example 1

[0047] A high-efficiency water treatment scale inhibitor comprises the following raw materials in percentage by weight: 20% polyacrylic acid, 10% 1-hydroxyethylidene-1,1-diphosphonic acid, 3.0% sodium hexametaphosphate, 0.7% sodium sulfate, 5.0% hydrolyzed polymaleic anhydride, 5.0% ethylenediaminetetramethylenephosphonic acid, 1.0% super chelating agent, and the balance being water.

[0048] The super chelating agent in this embodiment is a copolymer of triethyl 2,2',2''-aminotriacetate and ethylene glycol-based polymer, the main chemical components of which are (C 12 H 18 N2O4) n , the degree of polymerization is 7000, and the preparation method comprises the following steps:

[0049] 1) Dissolve 10 g of triethyl 2,2',2''-aminotriacetate in 250 mL of N,N-dimethylformamide, and add 15 g of sodium hydroxide to a 0.5 mol / L aqueous solution to obtain a mixed solution.

[0050] 2) After heating the mixed solution to 70°C, slowly add 30g of polyethylene glycol and 0.3g of Cu-BTC to carry out polymerization reaction. The addition should be completed within 1 hour. After the addition is complete, the reaction is continued for 1.5 hours.

[0051] 3) After the polymerization reaction is completed, hydrochloric acid with a concentration of 0.2 mol / L, which is 1 times the total mass of the polymerization reaction system, is added to terminate the reaction and precipitate the copolymer in the system. The copolymer is washed with ethanol and dried at 60°C for 5 hours to obtain a solid super chelating agent.

[0052] The preparation method of the high-efficiency water treatment scale inhibitor in this embodiment includes the following steps:

[0053] S1. Add polyacrylic acid, sodium sulfate, 1-hydroxyethylidene-1,1-diphosphonic acid, sodium hexametaphosphate and hydrolyzed polymaleic anhydride to water in sequence and stir thoroughly until dissolved;

[0054] S2. After raising the temperature to 55°C, add EDTA and super chelating agent successively, and continue stirring to ensure that all components are evenly mixed and stable;

[0055] S3. After cooling to room temperature, filter to obtain a clarified high-efficiency water treatment antiscalant.

[0056] Example 2

[0057] A high-efficiency water treatment scale inhibitor comprises the following raw materials in percentage by weight: 20% polyacrylic acid, 10% 1-hydroxyethylidene-1,1-diphosphonic acid, 3% sodium hexametaphosphate, 0.8% sodium sulfate, 5% hydrolyzed polymaleic anhydride, 5% ethylenediaminetetramethylenephosphonic acid, 1% super chelating agent, and the balance being water.

[0058] The super chelating agent in this embodiment is a copolymer of triethyl 2,2',2''-aminotriacetate and ethylene glycol-based polymer, the main chemical components of which are (C 12 H 18 N2O4) n , the degree of polymerization is 7000, and the preparation method comprises the following steps:

[0059] 1) Dissolve 15 g of triethyl 2,2',2''-aminotriacetate in 450 mL of N,N-dimethylacetamide, and add 25 g of potassium hydroxide to a 1 mol / L aqueous solution to obtain a mixed solution.

[0060] 2) After heating the mixed solution to 80°C, slowly add 40g of polyethylene glycol diacrylate and 0.6g of Cu-MOF-74 to carry out polymerization reaction. The addition is controlled to be completed within 1 hour, and the reaction is continued for 2 hours after the addition is completed.

[0061] 3) After the polymerization reaction is completed, sulfuric acid with a concentration of 0.3 mol / L in an amount 1.5 times the total mass of the polymerization reaction system is added to terminate the reaction and precipitate the copolymer in the system. The copolymer is washed with deionized water and dried at 70°C for 6 hours to obtain a solid super chelating agent.

[0062] The preparation method of the high-efficiency water treatment scale inhibitor in this embodiment includes the following steps:

[0063] S1. Add polyacrylic acid, sodium sulfate, 1-hydroxyethylidene-1,1-diphosphonic acid, sodium hexametaphosphate and hydrolyzed polymaleic anhydride to water in sequence and stir thoroughly until dissolved;

[0064] S2. After raising the temperature to 60°C, add EDTA and super chelating agent successively, and continue stirring to ensure that all components are evenly mixed and stable;

[0065] S3. After cooling to room temperature, filter to obtain a clarified high-efficiency water treatment antiscalant.

[0066] Example 3

[0067] A high-efficiency water treatment scale inhibitor comprises the following raw materials in percentage by weight: 25% polyacrylic acid, 12% 1-hydroxyethylidene-1,1-diphosphonic acid, 4% sodium hexametaphosphate, 1% sodium sulfate, 7% hydrolyzed polymaleic anhydride, 8% ethylenediaminetetramethylenephosphonic acid, 1.2% super chelating agent, and the balance being water.

[0068] The super chelating agent in this embodiment is a copolymer of triethyl 2,2',2''-aminotriacetate and ethylene glycol-based polymer, the main chemical components of which are (C 12 H 18 N2O4) n , the degree of polymerization is 9000, and the preparation method comprises the following steps:

[0069] 1) Dissolve 20 g of triethyl 2,2',2''-aminotriacetate in 500 mL of dimethyl sulfoxide, and add 35 g of sodium hydroxide to a 0.8 mol / L aqueous solution to obtain a mixed solution.

[0070] 2) After heating the mixed solution to 75°C, slowly add 50g polyethylene glycol and 1g Cu-TPA to carry out polymerization reaction. The addition should be completed within 1 hour. After the addition is complete, the reaction is continued for 2 hours.

[0071] 3) After the polymerization reaction is completed, hydrochloric acid with a concentration of 0.4 mol / L in an amount 1.2 times the total mass of the polymerization reaction system is added to terminate the reaction and precipitate the copolymer in the system. The copolymer is washed with methanol and dried at 65°C for 8 hours to obtain a solid super chelating agent.

[0072] The preparation method of the high-efficiency water treatment scale inhibitor in this embodiment includes the following steps:

[0073] S1. Add polyacrylic acid, sodium sulfate, 1-hydroxyethylidene-1,1-diphosphonic acid, sodium hexametaphosphate and hydrolyzed polymaleic anhydride to water in sequence and stir thoroughly until dissolved;

[0074] S2. After raising the temperature to 55°C, add EDTA and super chelating agent successively, and continue stirring to ensure that all components are evenly mixed and stable;

[0075] S3. After cooling to room temperature, filter to obtain a clarified high-efficiency water treatment antiscalant.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is that no super chelating agent is added.

[0078] Comparative Example 2

[0079] Comparative Example 2 is a commercially available polyacrylic acid scale inhibitor.

[0080] Application Examples

[0081] The scale inhibitors in each example and comparative example were applied to a circulating cooling water system by adding a quantitative amount of the scale inhibitor to the water system via a dosing pump. The water quality conditions and scale inhibitor dosage are detailed in Table 1. The scale inhibition performance of each test group was tested in accordance with GB / T 16632-2019, "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method." The results are shown in Table 1.

[0082] Table 1

[0083]

[0084] As can be seen from Table 1, the scale inhibition rate of the comparative example under various conditions is significantly lower than that of the embodiment, indicating its insufficiency in scale inhibition effect; the scale inhibition performance of the embodiment is significantly improved, especially under extreme water conditions of high temperature and high hardness, and is significantly better than traditional commercially available scale inhibitors.

[0085] The above embodiments are merely examples for clarification and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications may be made based on the above descriptions. It is not necessary and impossible to enumerate all implementation methods here, and any obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A high-efficiency water treatment scale inhibitor, characterized in that: The invention comprises the following raw materials in percentage by weight: 15-30% polyacrylic acid, 5-15% 1-hydroxyethylidene-1,1-diphosphonic acid, 1-5% sodium hexametaphosphate, 0.5-1% sodium sulfate, 3-8% hydrolyzed polymaleic anhydride, 2-10% ethylenediaminetetramethylenephosphonic acid, 0.3-1.5% super chelating agent, and the balance is water; the super chelating agent is a copolymer of triethyl 2,2',2''-aminotriacetate and an ethylene glycol-based polymer. The preparation method comprises the following steps: 1) dissolving triethyl 2,2',2''-aminotriacetate in a polar solvent, and then adding a hydrolyzing agent to obtain a mixed solution; the hydrolyzing agent is one of sodium hydroxide and potassium hydroxide; 2) After heating the mixed solution to a polymerization temperature, slowly adding an ethylene glycol-based polymer and a polymerization catalyst thereto to carry out a polymerization reaction; the ethylene glycol-based polymer is one of polyethylene glycol and polyethylene glycol diacrylate; and the polymerization catalyst is a copper-based MOF material; 3) After the polymerization reaction is completed, a dilute acid solution is added to terminate the reaction and precipitate the copolymer in the system. The copolymer is washed and dried to obtain a solid super chelating agent.

2. The high-efficiency water treatment scale inhibitor according to claim 1, characterized in that: The main chemical components of the super chelating agent are (C 12 H 18 N2O4) n , the degree of polymerization is 5000~10000.

3. The high-efficiency water treatment scale inhibitor according to claim 1, characterized in that: The mass ratio of the ethylene glycol-based polymer to triethyl 2,2',2''-aminotriacetate is (2-5):

1.

4. The high-efficiency water treatment scale inhibitor according to claim 1, characterized in that: The mass ratio of the polymerization catalyst to triethyl 2,2',2''-aminotriacetate is (0.01-0.05):

1.

5. The high-efficiency water treatment scale inhibitor according to claim 1, characterized in that: The mass ratio of the hydrolyzing agent to triethyl 2,2',2''-aminotriacetate is (1.5-2):

1.

6. The high-efficiency water treatment scale inhibitor according to claim 1, characterized in that: The polymerization temperature is 70-90° C.; the total polymerization reaction time is 2-3 hours, wherein the ethylene glycol-based polymer and the polymerization catalyst are added for 0.5-1 hour, and the reaction is continued for 1.5-2 hours after the addition is completed.

7. The high-efficiency water treatment scale inhibitor according to claim 1, characterized in that: The polar solvent is one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; the mass ratio of the triethyl 2,2',2''-aminotriacetate to the volume ratio of the polar solvent is 1g: (25-50)mL.

8. The method for preparing a high-efficiency water treatment scale inhibitor according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Add polyacrylic acid, sodium sulfate, 1-hydroxyethylidene-1,1-diphosphonic acid, sodium hexametaphosphate and hydrolyzed polymaleic anhydride to water in sequence and stir thoroughly until dissolved; S2. After raising the temperature to 50-60°C, add EDTA and super chelating agent successively, and continue stirring to ensure that all components are evenly mixed and stable; S3. After cooling to room temperature, filter to obtain a clarified high-efficiency water treatment antiscalant.

9. Use of the high-efficiency water treatment scale inhibitor according to any one of claims 1 to 7, characterized in that: The applicable temperature range of the high-efficiency water treatment scale inhibitor is 20-90° C., and the applicable hardness range is 100-1000 mg / L in terms of CaCO 3 .

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