Solid slow-release scale inhibitor and preparation method thereof

Abstract

The invention relates to the technical field of water treatment agents, and provides a solid slow-release scale inhibitor and a preparation method thereof. The preparation method of the solid slow-release scale inhibitor comprises the following steps: dispersing an aminated MOFs material in a mixed solvent of methanol and water, adding poly (N-isopropylacrylamide) and a cuprous bromide / pentamethyldiethylenetriamine catalytic system, and performing separation and freeze drying after reaction to obtain a temperature-sensitive functionalized MOFs material; dispersing the hyperbranched polyaspartic acid-itaconic acid copolymer in a mixed solvent of methanol and water, adding the temperature-sensitive functionalized MOFs material, reacting, and drying to obtain a polymer-loaded MOFs material; and dissolving zirconium acetate in water, adjusting the pH value to 4.0, adding the polymer-loaded MOFs material, carrying out a reaction, and carrying out centrifugal washing and drying. The solid slow-release scale inhibitor provided by the invention has a stable and effective scale inhibition effect.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment agents, and specifically, to a solid slow-release scale inhibitor and a preparation method thereof. Background Art

[0002] In industrial production, civil facilities, and many water-related systems, the formation of scale is a common and urgent problem to be solved. Scale is mainly composed of precipitates such as carbonates and sulfates of calcium, magnesium and other ions, and it will gradually deposit on the inner surfaces of equipment such as pipelines, heat exchangers, and boilers. The accumulation of scale will significantly reduce the heat conduction efficiency of the equipment, increase energy consumption, and may even cause equipment blockage and damage, seriously affecting the normal operation of the system, shortening the service life of the equipment, and bringing huge economic losses and safety hazards. Therefore, the research and application of scale inhibitors are of great significance for ensuring the stable operation of relevant systems and improving energy utilization efficiency. Among them, solid slow-release scale inhibitors have received extensive attention in recent years due to their unique advantages.

[0003] A solid slow-release scale inhibitor is a solid agent that can slowly release effective scale-inhibiting components over a long period of time. Compared with traditional liquid scale inhibitors, it has many advantages. First of all, solid slow-release scale inhibitors are convenient for storage and transportation, and there are no problems such as leakage and volatilization that may occur in liquid scale inhibitors, reducing the safety risks and costs during storage and transportation. Secondly, the slow-release characteristics enable the scale inhibitor to continuously and stably play a role in the system, avoiding the problem of unstable scale-inhibiting effect caused by excessive fluctuations in the concentration of the scale inhibitor, thereby extending the service life of the scale inhibitor, reducing the addition times and labor costs. In addition, solid slow-release scale inhibitors can also be designed into different shapes and sizes, such as granular and block-shaped, according to different usage scenarios and requirements, which is convenient for dosing and use in various equipment.

[0004] At present, for some solid slow-release scale inhibitors on the market, their slow-release performance is difficult to accurately control. In practical applications, the release rate of the scale inhibitor may be affected by various factors, such as water temperature, water flow rate, and water quality changes. When the water temperature rises or the water flow rate increases, the release rate of the scale inhibitor may suddenly increase, resulting in a large amount of the scale inhibitor being released in a short time, not only causing waste of the agent, but also possibly having an adverse impact on the system due to excessive local concentration; while when the water temperature decreases or the water flow rate slows down, the release rate of the scale inhibitor may be too slow to timely supplement the consumed scale-inhibiting components in the system, making the scale-inhibiting effect greatly reduced. This instability of the slow-release performance makes it difficult for existing solid slow-release scale inhibitors to maintain a stable and effective scale-inhibiting effect under various complex working conditions. In addition, although some existing solid slow-release scale inhibitors can achieve the slow-release function, their scale-inhibiting efficiency is not ideal. Based on this, the present invention proposes a solid slow-release scale inhibitor and a preparation method thereof. Summary of the Invention

[0005] The present invention provides a solid slow-release scale inhibitor and a preparation method thereof, which improve the ability of the solid slow-release scale inhibitor to maintain a stable and effective scale inhibition effect under various complex working conditions; meanwhile, the scale inhibition efficiency of the existing solid slow-release scale inhibitor is improved.

[0006] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a preparation method of a solid slow-release scale inhibitor, and the steps include: (1) Dispersing the amino-functionalized MOFs material in a mixed solvent of methanol and water, adding poly(N-isopropylacrylamide), a copper bromide / pentamethyldiethylenetriamine catalytic system, separating and freeze-drying after the reaction to obtain a temperature-sensitive functionalized MOFs material; (2) Dispersing the hyperbranched polyaspartic acid-itaconic acid copolymer in a mixed solvent of methanol and water, adding the temperature-sensitive functionalized MOFs material, and drying after the reaction to obtain the MOFs material loaded with the polymer; (3) Dissolving zirconium acetate in water, adjusting the pH to 4.0, adding the MOFs material loaded with the polymer, and centrifuging, washing and drying after the reaction to obtain the product.

[0007] As a further technical solution, the preparation method of the amino-functionalized MOFs material includes: dispersing the MOFs material in toluene, adding 3-aminopropyltriethoxysilane, refluxing at 75-85°C for 5-7 h under nitrogen protection, and centrifuging, washing and drying to obtain the amino-functionalized MOFs material.

[0008] As a further technical solution, the preparation method of the MOFs material includes: dispersing ferric chloride hexahydrate and terephthalic acid in N,N-dimethylformamide, carrying out a solvothermal reaction at 105-115°C for 23-25 h, centrifuging, collecting, washing and activating to obtain the MOFs material.

[0009] As a further technical solution, the activation temperature is 75-85°C and the activation time is 11-13 h.

[0010] As a further technical solution, the reaction condition in step (1) is to carry out an atom transfer radical polymerization reaction at 50-60°C for 8-10 h.

[0011] As a further technical solution, the freeze-drying condition in step (1) is to carry out freeze-drying at -20~-30°C for 22-26 h.

[0012] As a further technical solution, the dosage ratio of the aminated MOFs material, methanol, water, poly(N-isopropylacrylamide), cuprous bromide and pentamethyldiethylenetriamine in the step (1) is (4-6) g : (150-170) mL : (30-50) mL : (10-14) g : (0.1-0.3) g : (0.2-0.4) mL.

[0013] As a further technical solution, the reaction conditions in the step (2) are impregnation for 5-6 h under a vacuum of 45-55 kPa and at 55-65 °C, and repeated 3 times.

[0014] As a further technical solution, the dosage ratio of the hyperbranched polyaspartic acid-itaconic acid copolymer, methanol, water and the temperature-sensitive functionalized MOFs material in the step (2) is (14-16) g : (100-110) mL : (40-50) mL : (9-11) g.

[0015] As a further technical solution, the preparation method of the hyperbranched polyaspartic acid-itaconic acid copolymer includes: mixing aspartic acid and itaconic acid, adding a citric acid catalyst, heating to 180 °C ± 5 °C at a rate of 5 °C / min and reacting for 2-3 h to obtain a prepolymer, crushing and dissolving it in water, dropping epichlorohydrin, controlling the pH to 9.0-9.5, and reacting at 84-86 °C for 4-5 h to obtain it.

[0016] As a further technical solution, the reaction conditions in the step (3) are stirring and reacting at 55-65 °C and 200-300 rpm for 10-12 h.

[0017] As a further technical solution, the dosage ratio of zirconium acetate, water and the MOFs material loaded with the polymer in the step (3) is (2.2-2.6) g : (45-55) mL : (9.5-10.5) g.

[0018] In the second aspect, the present invention proposes a solid slow-release scale inhibitor prepared by using the aforementioned method.

[0019] The working principle and beneficial effects of the present invention are as follows: The present invention utilizes the synergistic modification of MOFs amination-thermosensitive functionalization to enhance the scale inhibition effect. First, amino groups are introduced onto the surface of MOFs. The amino groups have strong reaction activity and can form strong interfacial binding forces with the polymer molecules added subsequently, enhancing the interaction between MOFs and polymers, thereby improving the overall stability and scale inhibition performance of the scale inhibitor. This enhancement of interfacial binding helps the uniform loading of the polymer on the surface of MOFs, and during subsequent use, reduces the shedding of the polymer, ensuring the durability of the scale inhibition effect. In addition, based on the thermosensitive property of poly(N-isopropylacrylamide) (PNIPAM). The PNIPAM segments undergo conformational changes at different temperatures. When the temperature is lower than its lower critical solution temperature (LCST), the PNIPAM segments are in a stretched state and can adsorb more scale inhibition components; when the temperature is higher than the LCST, the PNIPAM segments contract and release the adsorbed scale inhibition components, achieving intelligent release. This thermosensitive function enables the scale inhibitor to automatically adjust the release rate of the scale inhibition components according to the change in environmental temperature, improving the adaptability and effectiveness of the scale inhibitor under different temperature conditions.

[0020] In the present invention, a hyperbranched polyaspartic acid-itaconic acid copolymer is used for loading. Hyperbranched polymers have a unique three-dimensional spherical structure and a large number of terminal functional groups. Their polycarboxylic acid groups can chelate with scale-forming ions such as calcium and magnesium in water, thereby effectively preventing the formation of scale. At the same time, the hyperbranched structure provides a large steric hindrance, further inhibiting the growth and aggregation of scale crystals. Through multiple impregnation processes, the gradient distribution of the polymer in MOFs is ensured. This distribution method can make full use of the pore structure of MOFs, increase the loading amount of the polymer, and make the scale inhibition components more uniform and persistent during the release process, extending the slow-release time.

[0021] In the present invention, zirconium acetate is used to promote crosslinking and strengthening. Since zirconium acetate undergoes hydrolysis reaction in solution to generate Zr-O coordination bonds. These coordination bonds can crosslink with the functional groups on the surface of MOFs and the loaded polymer molecules to form a stable three-dimensional network structure. This crosslinked network structure significantly enhances the thermal stability of the material, and can effectively prevent the decomposition of the material and the destruction of the structure in a high-temperature environment, ensuring that the scale inhibitor can still maintain stable scale inhibition performance under high-temperature conditions. At the same time, the crosslinked network can also maintain the structural integrity of the material, reduce the loss of scale inhibition components during use, and further extend the service life of the scale inhibitor.

[0022] During the solvothermal reaction process of the present invention, the reactants undergo chemical reactions in a solvent environment of high temperature and high pressure to form MOFs crystals with a regular pore structure. On this basis, subsequent activation treatment can further remove impurities and unreacted raw materials in the MOFs pores, making the pores more unobstructed and increasing the porosity of MOFs. The complete MOFs framework has a large specific surface area and a rich pore structure, which can provide more active sites for the loading of polymers, increase the loading amount of polymers, and thus improve the scale inhibition performance of the scale inhibitor. If the activation treatment is not carried out, the MOFs pores are blocked, the loading amount of polymers decreases, resulting in a decrease in the scale inhibition rate.

[0023] Through three impregnation processes in the present invention, the loading of polymers in MOFs is more sufficient and uniform. During each impregnation process, polymer molecules gradually penetrate into the pores of MOFs and interact with the pore walls. Multiple impregnations can ensure a gradient distribution of polymers in MOFs, gradually increasing the polymer content from the surface to the inside. This distribution mode enables the scale inhibition components to be released in a certain order and rate during the release process, prolonging the slow release time. Compared with a single impregnation, three impregnations can better utilize the pore structure of MOFs, improve the loading efficiency of polymers, and thus significantly enhance the slow release performance of the scale inhibitor. In addition, the amino groups in APTES molecules can form stronger chemical bonds and interactions between the surface of MOFs and polymer molecules, enhancing the interfacial binding force. While the interfacial binding force of KH550 is relatively weak, resulting in insufficient firm binding between the polymer and MOFs during the use of the scale inhibitor, which is prone to detachment and thus reduces the scale inhibition rate. Specific embodiments

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention. It should be noted that the CAS number of poly(N-isopropylacrylamide) in the present invention is 25189-55-3, which is purchased from Shanghai Beixinke Technology Development Co., Ltd.

[0025] Example 1 In this example, a preparation method of a solid slow-release scale inhibitor is provided, and the steps include: (1) Disperse 2.45 g of ferric chloride hexahydrate and 0.83 g of terephthalic acid in 30 mL of N,N-dimethylformamide, carry out a solvothermal reaction at 110 °C for 24 h, collect by centrifugation, wash 3 times with DMF and methanol in sequence, and obtain MOFs material after activation at 80 °C for 12 h; (2) Disperse 1 g of MOFs material in 50 mL of toluene, add 3-aminopropyltriethoxysilane, reflux at 80 °C for 6 h under nitrogen protection, centrifuge and wash with ethanol until neutral, and dry at 60 °C to obtain the aminated MOFs material; (3) Disperse 5 g of aminated MOFs material in a mixed solvent of 160 mL of methanol and 40 mL of water, add 12 g of poly(N-isopropylacrylamide), 0.2 g of copper(I) bromide / 0.3 mL of pentamethyldiethylenetriamine catalytic system, and carry out atom transfer radical polymerization reaction at 55 °C for 9 h, then separate and freeze-dry at -25 °C for 24 h to obtain the temperature-sensitive functionalized MOFs material; (4) Mix aspartic acid and itaconic acid in a molar ratio of 4:1, add 3% of citric acid catalyst based on the total monomer mass, heat up to 180 °C at a rate of 5 °C / min and react for 2.5 h to obtain a prepolymer, crush it and dissolve it in water, dropwise add 0.5 mol% of epichlorohydrin based on the total monomer, add 30% NaOH by mass concentration to control the pH to 9.2, and react at 85 °C for 4.5 h to obtain hyperbranched polyaspartic acid-itaconic acid copolymer; (5) Disperse 15 g of hyperbranched polyaspartic acid-itaconic acid copolymer in a mixed solvent of 105 mL of methanol and 45 mL of water, add 10 g of temperature-sensitive functionalized MOFs material, impregnate at 50 kPa vacuum and 60 °C for 5.5 h, repeat 3 times, and then vacuum dry at 60 °C to constant weight to obtain the MOFs material loaded with polymer; (6) Dissolve 2.4 g of zirconium acetate in 50 mL of water, adjust the pH to 4.0 with 0.1 M HNO3, add 10 g of the MOFs material loaded with polymer, stir and react at 60 °C and 250 rpm for 11 h, then centrifuge, wash and dry to obtain.

[0026] Example 2 In this example, a preparation method of a solid slow-release scale inhibitor is provided, and the steps include: (1) Disperse 2.45 g of ferric chloride hexahydrate and 0.83 g of terephthalic acid in 30 mL of N,N-dimethylformamide, carry out solvothermal reaction at 105 °C for 23 h, centrifuge and collect, wash 3 times with DMF and methanol in sequence, and activate at 75 °C for 11 h to obtain the MOFs material; (2) Disperse 1 g of MOFs material in 50 mL of toluene, add 3-aminopropyltriethoxysilane, reflux at 75 °C for 5 h under nitrogen protection, centrifuge and wash with ethanol until neutral, and dry at 60 °C to obtain the aminated MOFs material; (3) Disperse 4 g of the aminated MOF material in a mixed solvent of 150 mL of methanol and 30 mL of water, add 10 g of poly(N-isopropylacrylamide), and 0.1 g of cuprous bromide / 0.2 mL of pentamethyldiethylenetriamine catalytic system. Carry out atom transfer radical polymerization reaction at 50 °C for 8 h, then separate and freeze-dry at -20 °C for 22 h to obtain the temperature-sensitive functionalized MOF material; (4) Mix aspartic acid and itaconic acid in a molar ratio of 4:1, add 3% of the total monomer mass of citric acid catalyst, heat up to 180 °C at a rate of 5 °C / min and react for 2 h to obtain a prepolymer. After pulverization, dissolve it in water, dropwise add 0.5 mol% of epichlorohydrin based on the total monomer, add NaOH with a mass concentration of 30% to control the pH to 9.0, and react at 84 °C for 4 h to obtain hyperbranched polyaspartic acid-itaconic acid copolymer; (5) Disperse 14 g of hyperbranched polyaspartic acid-itaconic acid copolymer in a mixed solvent of 100 mL of methanol and 40 mL of water, add 9 g of the temperature-sensitive functionalized MOF material, impregnate at a vacuum degree of 45 kPa and 55 °C for 5 h, repeat 3 times, and then vacuum dry at 60 °C to constant weight to obtain the MOF material loaded with the polymer; (6) Dissolve 2.2 g of zirconium acetate in 45 mL of water, adjust the pH to 4.0 with 0.1 M HNO3, add 9.5 g of the MOF material loaded with the polymer, stir and react at 55 °C and 200 rpm for 10 h, then centrifuge, wash and dry to obtain the product.

[0027] Example 3 In this example, a preparation method of a solid slow-release scale inhibitor is provided, and the steps include: (1) Disperse 2.45 g of ferric chloride hexahydrate and 0.83 g of terephthalic acid in 30 mL of N,N-dimethylformamide, carry out solvothermal reaction at 115 °C for 25 h, collect by centrifugation, wash 3 times with DMF and methanol in sequence, and activate at 85 °C for 13 h to obtain the MOF material; (2) Disperse 1 g of the MOF material in 50 mL of toluene, add 3-aminopropyltriethoxysilane, reflux at 85 °C for 7 h under nitrogen protection, centrifuge and wash with ethanol until neutral, and dry at 60 °C to obtain the aminated MOF material; (3) Disperse 6 g of the aminated MOF material in a mixed solvent of 170 mL of methanol and 50 mL of water, add 14 g of poly(N-isopropylacrylamide), and 0.3 g of cuprous bromide / 0.4 mL of pentamethyldiethylenetriamine catalytic system. Carry out atom transfer radical polymerization reaction at 60 °C for 10 h, then separate and freeze-dry at -30 °C for 26 h to obtain the temperature-sensitive functionalized MOF material; (4) Mix aspartic acid and itaconic acid in a molar ratio of 4:1, add 3% of citric acid catalyst based on the total monomer mass, heat up to 180 °C at a rate of 5 °C / min and react for 3 h to obtain a prepolymer. After pulverization, it is dissolved in water, and epichlorohydrin accounting for 0.5 mol% of the total monomer is added dropwise. Add NaOH with a mass concentration of 30% to control the pH to 9.5, and react at 86 °C for 5 h to obtain hyperbranched polyaspartic acid-itaconic acid copolymer; (5) Disperse 16 g of hyperbranched polyaspartic acid-itaconic acid copolymer in a mixed solvent of 110 mL of methanol and 50 mL of water, add 11 g of thermosensitive functionalized MOFs material, impregnate at a vacuum degree of 55 kPa and 65 °C for 6 h, repeat 3 times, and then dry at 60 °C under vacuum until constant weight to obtain MOFs material loaded with polymer; (6) Dissolve 2.6 g of zirconium acetate in 55 mL of water, adjust the pH to 4.0 with 0.1 M HNO3, add 10.5 g of MOFs material loaded with polymer, stir and react at 65 °C and 300 rpm for 12 h, then centrifuge, wash and dry to obtain the product.

[0028] Example 4 In this example, a preparation method of a solid slow-release scale inhibitor is provided, and the steps include: (1) Disperse 2.45 g of ferric chloride hexahydrate and 0.83 g of terephthalic acid in 30 mL of N,N-dimethylformamide, carry out a solvothermal reaction at 105 °C for 25 h, collect by centrifugation, wash 3 times with DMF and methanol in sequence, and activate at 75 °C for 13 h to obtain MOFs material; (2) Disperse 1 g of MOFs material in 50 mL of toluene, add 3-aminopropyltriethoxysilane, reflux at 75 °C for 7 h under nitrogen protection, centrifuge and wash with ethanol until neutral, and dry at 60 °C to obtain amino-functionalized MOFs material; (3) Disperse 4 g of amino-functionalized MOFs material in a mixed solvent of 170 mL of methanol and 30 mL of water, add 14 g of poly(N-isopropylacrylamide), 0.1 g of cuprous bromide / 0.4 mL of pentamethyldiethylenetriamine catalytic system, carry out atom transfer radical polymerization reaction at 50 °C for 10 h, then separate and freeze-dry at -20 °C for 26 h to obtain thermosensitive functionalized MOFs material; (4) Mix aspartic acid and itaconic acid in a molar ratio of 4:1, add 3% of citric acid catalyst based on the total monomer mass, heat up to 180 °C at a rate of 5 °C / min and react for 3 h to obtain a prepolymer. After pulverization, it is dissolved in water, and epichlorohydrin accounting for 0.5 mol% of the total monomer is added dropwise. Add NaOH with a mass concentration of 30% to control the pH to 9.0, and react at 86 °C for 4 h to obtain hyperbranched polyaspartic acid-itaconic acid copolymer; (5) Disperse 16 g of hyperbranched polyaspartic acid-itaconic acid copolymer in a mixed solvent of 100 mL of methanol and 50 mL of water, add 9 g of temperature-sensitive functionalized MOFs material, impregnate at a vacuum degree of 55 kPa and a temperature of 55 °C for 6 h, repeat 3 times, and then dry in vacuum at 60 °C to constant weight to obtain the MOFs material loaded with polymer; (6) Dissolve 2.2 g of zirconium acetate in 55 mL of water, adjust the pH to 4.0 with 0.1 M HNO3, add 9.5 g of the MOFs material loaded with polymer, stir and react at 65 °C and 200 rpm for 12 h, then centrifuge, wash and dry to obtain.

[0029] Comparative Example 1 In this comparative example, step (3) was cancelled, and the amino-functionalized MOFs material prepared in step (2) was directly subjected to the reaction in step (5), and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0030] Comparative Example 2 In this comparative example, steps (2) and (3) were cancelled, and the MOFs material prepared in step (1) was directly subjected to the reaction in step (5), and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0031] Comparative Example 3 In this comparative example, step (6) was cancelled, and the MOFs material loaded with polymer prepared in step (5) was the scale inhibitor, and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0032] Comparative Example 4 In this comparative example, the solvent thermal activation was not carried out in step (1), and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0033] Comparative Example 5 In this comparative example, the step of "impregnating at a vacuum degree of 50 kPa and a temperature of 60 °C for 5.5 h" in step (5) was not repeated, and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0034] Comparative Example 6 In this comparative example, 3-aminopropyltriethoxysilane in step (2) was replaced with γ-aminopropyltriethoxysilane KH550, and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0035] Test Example 1: The following tests were carried out on the solid slow-release scale inhibitors prepared in the foregoing Examples 1-4 and Comparative Examples 1-6: Scale inhibition rate test: Refer to GB / T 16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method" for testing, and prepare a solution containing Ca 2+ (250 mg / L) and HCO3 -Simulated water samples (500 mg / L) were added with 1 g / L scale inhibitor, filtered after being kept at a constant temperature of 80 °C for 6 h, and the Ca concentration in the filtrate was measured to calculate the scale inhibition rate; 2+ Concentration, calculate the scale inhibition rate; Scale inhibition rate (%) = C 样 −C 空 / C 初 −C 空 × 100%; where C 样 : Ca concentration in the sample group; C 2+ : Ca concentration after precipitation in the blank group; C 空 : Ca concentration after precipitation in the blank group; C 2 + : Ca concentration after precipitation in the blank group; C 初 : Initial Ca concentration; 2+ Concentration; Sustained release time test: The scale inhibitor was placed in a dynamic circulation device (flow rate 2 L / h, 25 °C), and the concentration of the active ingredient of the scale inhibitor in the solution was measured daily until the time when the concentration dropped below 10% of the initial value; Temperature resistance test: After the scale inhibitor was soaked in water at 80 °C for 48 h, the retention rate of the scale inhibition rate was measured; pH adaptability test: The change of the scale inhibition rate was tested in the range of pH 5.0 - 10.0; The results are shown in Table 1 below: Table 1

[0036] According to the data, the thermosensitive functionalization in step 3 increased the sustained release time by 120% - 150%, proving that the PNIPAM thermosensitive segment achieved intelligent release through conformational changes; the amidation treatment in step 2 increased the scale inhibition rate by 9.7%, indicating that the amino group enhanced the interfacial binding between MOFs and the polymer; the zirconium acetate crosslinking in step 6 significantly improved the temperature resistance, and the Zr - O coordination bond effectively enhanced the thermal stability of the material. The solvothermal activation in step 1 affected the porosity, and the scale inhibition rate of the non - activated group in Comparative Example 4 decreased by 27.9%, indicating that the complete MOFs skeleton was crucial for the loading capacity. The three - time impregnation process in step 5 extended the sustained release time by 86%, and repeated loading ensured the gradient distribution of the polymer in MOFs. In addition, the selection of the silane coupling agent had a significant impact. The interfacial binding force of KH550 in Comparative Example 6 was weaker than that of APTES, resulting in a 9.5% decrease in the scale inhibition rate.

[0037] Example 1 The scale inhibition rate fluctuation is maintained within <±2.5% in a wide pH range. The polycarboxylic acid groups of the hyperbranched polymer provide pH buffering capacity. In different pH environments, the polycarboxylic acid groups will undergo protonation and deprotonation reactions, thereby regulating the charge distribution and pH value of the system. This buffering effect enables the scale inhibitor to maintain a relatively stable structure and performance in water environments with different pH values, ensuring that the scale inhibition components can effectively interact with scale-forming ions and prevent the formation of scale. However, due to the lack of a stable cross-linked network structure in the uncross-linked group, when the pH fluctuates, the structure of the material is prone to change, resulting in a large fluctuation in the scale inhibition rate, indicating that the cross-linked network plays a decisive role in maintaining structural stability, and further affecting the environmental adaptability of the scale inhibitor. In addition, the pH fluctuation of the uncross-linked group in Comparative Example 3 reaches ±7.5%, indicating that the cross-linked network plays a decisive role in maintaining structural stability.

[0038] 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 principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a solid slow-release scale inhibitor, characterized in that the steps Comprising: (1) Dispersing the aminated MOFs material in a mixed solvent of methanol and water, adding poly(N-isopropylacrylamide), and a copper(I) bromide / pentamethyldiethylenetriamine catalytic system, separating and freeze-drying after the reaction to obtain a temperature-sensitive functionalized MOFs material; (2) Dispersing the hyperbranched polyaspartic acid-itaconic acid copolymer in a mixed solvent of methanol and water, adding the temperature-sensitive functionalized MOFs material, and drying after the reaction to obtain an MOFs material loaded with the polymer; (3) Dissolving zirconium acetate in water, adjusting the pH to 4.0 ± 0.1, adding the MOFs material loaded with the polymer, and centrifuging, washing, and drying after the reaction to obtain the product.

2. The preparation method of a solid slow-release scale inhibitor according to claim 1, characterized in that The preparation method of the aminated MOFs material comprises: dispersing the MOFs material in toluene, adding 3-aminopropyltriethoxysilane, refluxing at 75-85 °C for 5-7 h under nitrogen protection, and centrifuging, washing, and drying to obtain the aminated MOFs material.

3. The preparation method of a solid slow-release scale inhibitor according to claim 2, characterized in that, The preparation method of the MOFs material comprises: dispersing ferric chloride hexahydrate and terephthalic acid in N,N-dimethylformamide, carrying out a solvothermal reaction at 105-115 °C for 23-25 h, centrifuging, collecting, washing, and activating to obtain the MOFs material.

4. The preparation method of a solid slow-release scale inhibitor according to claim 3, characterized in that, The activation temperature is 75-85 °C, and the activation time is 11-13 h.

5. The preparation method of a solid slow-release scale inhibitor according to claim 1, characterized in that, The reaction conditions in step (1) are to carry out an atom transfer radical polymerization reaction at 50-60 °C for 8-10 h.

6. The preparation method of a solid slow-release scale inhibitor according to claim 1, characterized in that, The freeze-drying conditions in step (1) are to carry out freeze-drying at -20 to -30 °C for 22-26 h.

7. The preparation method of a solid slow-release scale inhibitor according to claim 1, characterized in that, The reaction conditions in step (2) are to impregnate at a vacuum of 45-55 kPa and a temperature of 55-65 °C for 5-6 h, and repeat 3 times.

8. The preparation method of a solid slow-release scale inhibitor according to claim 1, characterized in that, The preparation method of the hyperbranched polyaspartic acid-itaconic acid copolymer comprises: mixing aspartic acid and itaconic acid, adding a citric acid catalyst, heating to 180 °C ± 5 °C at a rate of 5 °C / min and reacting for 2-3 h to obtain a prepolymer, pulverizing and dissolving it in water, dropping epichlorohydrin, controlling the pH to 9.0-9.5, and reacting at a temperature of 84-86 °C for 4-5 h to obtain the product.

9. The preparation method of a solid slow-release scale inhibitor according to claim 1, characterized in that, The reaction conditions in step (3) are to stir and react at 55-65 °C and 200-300 rpm for 10-12 h.

10. A solid slow-release scale inhibitor prepared by the preparation method of the solid slow-release scale inhibitor according to any one of claims 1-9.

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