Phosphorus-free reverse osmosis scale inhibitor, preparation method and application thereof
The phosphorus-free reverse osmosis antiscalant, which incorporates multifunctional groups through grafting modification, solves the problems of insufficient chelation capacity, dispersion performance and stability of existing phosphorus-free antiscalants under complex operating conditions, achieving high-efficiency scale inhibition and long-term stability, extending membrane service life and reducing energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG BAWOFU ENVIRONMENTAL PROTECTION TECH CO LTD
- Filing Date
- 2026-04-29
- Publication Date
- 2026-06-19
AI Technical Summary
Existing phosphorus-free reverse osmosis antiscalants have limited metal chelating ability, insufficient dispersion performance, and insufficient molecular structure stability under complex operating conditions such as high salt, high concentration ratio, and high hardness, leading to scaling, clogging, and performance degradation on the membrane surface.
The Mannich base reaction grafting modification introduces multifunctional active groups such as acrylate groups, 2-amino-8-hydroxyquinoline groups, silane groups, carboxyl groups, and sulfonic acid groups. These groups are covalently grafted and polymerized to form multi-heteroatom chelating sites, which enhance the metal chelating ability and dispersion performance, forming a protective layer to prevent scale deposition.
It achieves efficient chelation of metal ions under high salt and high temperature conditions, inhibits scale formation, improves dispersibility and stability, extends membrane life, and reduces operating energy consumption.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of scale inhibitor materials technology, specifically to a phosphorus-free reverse osmosis scale inhibitor, its preparation method, and its application. Background Technology
[0002] Reverse osmosis technology, as a highly efficient membrane separation technology, is widely used in power, petrochemical, electronics, biomedicine, and wastewater treatment, and is one of the core technologies for achieving water purification, reuse, and energy conservation and emission reduction. Antiscalants, as key auxiliary agents for the stable operation of reverse osmosis systems, primarily inhibit the deposition of various scales such as calcium carbonate, calcium sulfate, and silica scale within the system, preventing membrane element clogging, wear, and performance degradation, extending membrane lifespan, and reducing operating energy consumption. With increasingly stringent global environmental policies, traditional phosphorus-containing reverse osmosis antiscalants, which easily lead to eutrophication and red tides, have been gradually restricted or banned in many countries and regions. Developing green, efficient, and phosphorus-free reverse osmosis antiscalants suitable for complex operating conditions has become an inevitable trend and urgent need for the industry. Currently, the research and development of phosphorus-free reverse osmosis antiscalants mainly focuses on introducing chelating and dispersing functional groups through molecular structure modification to improve scale inhibition performance. However, due to limitations in modification technology, existing products are still difficult to fully adapt to the complex operating conditions of reverse osmosis systems with high salt content, high concentration ratio, and high hardness. A mature product with excellent scale inhibition efficiency, strong dispersibility, and long-term stability has not yet been formed.
[0003] Current phosphorus-free reverse osmosis antiscalant technology has several prominent drawbacks, all of which can be effectively addressed by this technical solution: First, its metal chelating ability is limited. Existing phosphorus-free antiscalants mostly rely on the weak coordination of single carboxyl and sulfonic acid groups, lacking strong chelating active sites with multiple heteroatoms. This makes it difficult to efficiently chelate scale-forming metal ions in water, resulting in poor scale inhibition effects on high-hardness water and easy scaling on the membrane surface. Second, its dispersion performance is insufficient and its anti-silica scale ability is weak. Existing products lack highly efficient dispersing groups, failing to effectively inhibit the aggregation and sedimentation of scale particles and colloidal particles. Furthermore, it has poor inhibition effects on silica scale, which is difficult to treat in reverse osmosis systems, easily causing membrane element blockage and restricting the high recovery rate operation of the system. Third, its molecular structure stability is insufficient. The functional groups of some modified phosphorus-free antiscalants are not firmly bonded to the molecular backbone, making them prone to hydrolysis and shedding under the harsh conditions of high temperature and high salt in reverse osmosis systems. This leads to a rapid decline in scale inhibition performance and an inability to maintain long-term stable operation. Summary of the Invention
[0004] The purpose of this invention is to provide a phosphorus-free reverse osmosis antiscalant, its preparation method, and its application, so as to solve the problems existing in the prior art.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A phosphorus-free reverse osmosis antiscalant, its preparation method, and its application are disclosed. The phosphorus-free reverse osmosis antiscalant is first prepared by grafting diethyl acetate acrylate and 2-amino-8-hydroxyquinoline using a Mannich base reaction to obtain an intermediate product, acrylic acid-grafted 2-amino-8-hydroxyquinoline. Subsequently, the obtained acrylic acid-grafted 2-amino-8-hydroxyquinoline is subjected to a ring-opening reaction with 3-glycidyl etheroxypropyltrimethoxysilane, and after complete reaction, a polymeric monomer is obtained. Finally, using the polymeric monomer, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid as polymerization reactants, the target product, the phosphorus-free reverse osmosis antiscalant, is obtained through a polymerization reaction.
[0006] As an optimization, the mass ratio of the polymeric monomer, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid is 10:30~40:50~60.
[0007] A method for preparing a phosphorus-free reverse osmosis antiscalant, applicable to any of the phosphorus-free reverse osmosis antiscalants described above, wherein the phosphorus-free reverse osmosis antiscalant comprises the following preparation steps: weighing polymeric monomers, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid in a mass ratio of 10:30~40:50~60; adding the above three raw materials to deionized water at a mass ratio of 10~15 times that of the polymeric monomers; after the addition is complete, heating to 75~85℃; after the heating is complete, adding dropwise a 10% ammonium persulfate solution at a mass ratio of 3.4~3.6 times that of the polymeric monomers and a 10% ferrous sulfate solution at a mass ratio of 8.5~9 times that of the polymeric monomers; maintaining the temperature for 2~2.5 hours after the addition is complete; cooling to 25~35℃ after the reaction is complete, thereby obtaining the phosphorus-free reverse osmosis antiscalant.
[0008] As an optimization, the polymer monomer includes the following preparation steps: 2-amino-8-hydroxyquinoline grafted with acrylic acid and 3-glycidyl etheroxypropyltrimethoxysilane are added to methanol, preheated to 75-85°C, and then N,N-diisopropylethylamine (0.75-0.8 times the mass of 2-amino-8-hydroxyquinoline grafted with acrylic acid) is added. The mixture is stirred and refluxed for 7-9 hours. After the reaction is completed, the mixture is cooled to 25-35°C, methanol is removed by rotary evaporator, and the product is washed 3-5 times with ethyl acetate. After washing, the product is filtered and dried to obtain the polymer monomer.
[0009] As an optimization, the acrylic acid grafted with 2-amino-8-hydroxyquinoline includes the following preparation steps: formaldehyde and 2-amino-8-hydroxyquinoline are added to ethanol at a mass ratio of 1:3.5~4, which is 3~4 times the mass of 2-amino-8-hydroxyquinoline. The pH of the system is adjusted to 4~5 using a 5% hydrochloric acid solution, and the mixture is refluxed at 75~80℃ for 2.5~3h. Then, diethyl acetate of acrylate is added dropwise at a mass ratio of 1.2~1.5 times the mass of 2-amino-8-hydroxyquinoline, and the mixture is refluxed at 75~80℃ for 1.5~2h. After the reaction is completed, the mixture is extracted with diethyl ether, and impurities are removed by rotary evaporation to obtain acrylic acid grafted with 2-amino-8-hydroxyquinoline.
[0010] As an optimization, the preparation steps of the diethyl acetate acrylate include the following: hydroxyethyl acrylate and triethylamine are added dropwise to acetyl chloride at a temperature of 0~5℃. After the addition is complete, the mixture is reacted at a temperature of 10~15℃ for 1~1.5h. After the reaction is completed, the mixture is filtered and the filtrate is collected. Then, diethyl ether and unreacted acetyl chloride are removed by rotary evaporation to obtain diethyl acetate acrylate.
[0011] As an optimization, the mass ratio of the acrylic acid grafted with 2-amino-8-hydroxyquinoline, 3-glycidyl etheroxypropyltrimethoxysilane and methanol is 1:4.4~4.6:20~25.
[0012] As an optimization, the mass ratio of hydroxyethyl acrylate, acetyl chloride and triethylamine is 2.2~2.5:2.4~2.6:1.
[0013] A scale inhibitor comprising the phosphorus-free reverse osmosis scale inhibitor as described in claim 1 or 2.
[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: This technical solution employs a series of multifunctional active groups, including acrylate groups, 2-amino-8-hydroxyquinoline groups, silane groups, carboxyl groups, and sulfonic acid groups, which are then covalently grafted and polymerized to achieve efficient scale inhibition in reverse osmosis through metal chelation solubilization, scale crystal lattice distortion, particle dispersion and suspension, and membrane surface antifouling protection. First, diethyl acetate acrylate was synthesized via a low-temperature acylation reaction, successfully introducing acrylate groups as the core active linker. These groups contain carbonyl oxygen atoms, enabling initial weak coordination complexation of calcium and magnesium ions in water, while retaining double-bond active sites. This provides stable covalent binding sites for subsequent Mannich grafting and final polymerization, firmly anchoring all functional groups to the molecular chain and avoiding the problems of functional component release, precipitation, and inactivation in traditional compound agents. This structurally ensures the stability of multi-group synergistic scale inhibition. Next, 2-amino-8-hydroxyquinoline was grafted onto the molecular chain via the Mannich base reaction, enhancing metal chelating ability. This group is rich in heteroatom coordination sites, including amino, hydroxyl, and quinoline ring nitrogen atoms, which can form stable five- and six-membered chelate rings with scale-forming metal ions in water. Through strong chelation and solubilization, the metal ions are firmly bound in the aqueous solution, completely blocking their pathway to combine with carbonate and sulfate ions to form scale crystals. Simultaneously, the conjugated structure of the quinoline ring produces a strong lattice distortion effect on the initial scale crystal formation. This process disrupts the regular crystalline morphology of carbonate and sulfate scale, preventing the formation of dense, hard scale. It also chelates essential metal nutrient ions for microorganisms, inhibiting the formation of biological slime. Subsequently, silane groups are introduced through an epoxy ring-opening reaction. The silanol groups generated by the hydrolysis of silanes can form strong hydrogen bonds with silicate ions and silica gel particles in the water, preventing the polymerization and deposition of silicon molecules through dispersion and suspension. At the same time, the silanol groups can assist in coordinating metal ions, further enhancing the overall chelation capacity. They can also form a protective layer on the surface of the reverse osmosis membrane, preventing the adsorption and adhesion of scale and impurities. Finally, the polymer monomer is copolymerized with acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, introducing two strong scale-inhibiting groups: carboxyl groups and sulfonic acid groups. Carboxyl groups can form highly stable water-soluble chelates with scale-forming ions such as calcium, magnesium, barium, and strontium, significantly improving the chelation and solubilization capacity. Sulfonic acid groups have a strong resistance to electrolyte interference, and can still disperse scale crystals through electrostatic repulsion and steric hindrance under reverse osmosis conditions of high salt, high TDS, and high recovery rate, preventing their deposition on the membrane surface. Detailed Implementation
[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0016] Example 1 S1. Weigh hydroxyethyl acrylate, acetyl chloride and triethylamine according to a mass ratio of 2.2:2.4:1. Add hydroxyethyl acrylate and triethylamine dropwise to acetyl chloride at a temperature of 0℃. After the addition is complete, react at a temperature of 10℃ for 1 hour. After the reaction is complete, filter and collect the filtrate. Then, remove the diethyl ether and unreacted acetyl chloride by rotary evaporation to obtain diethyl acetate acrylate. S2. Formaldehyde and 2-amino-8-hydroxyquinoline were added to ethanol at a mass ratio of 1:3.5 to 3 times the mass of 2-amino-8-hydroxyquinoline. The pH of the system was adjusted to 4 using 5% hydrochloric acid solution, and the mixture was refluxed at 75°C for 2.5 h. Then, diethyl acetate acrylate at a mass ratio of 1.2 times the mass of 2-amino-8-hydroxyquinoline was added dropwise, and the mixture was refluxed at 75°C for another 1.5 h. After the reaction was completed, the mixture was extracted with diethyl ether, and impurities were removed by rotary evaporation to obtain acrylic acid-grafted 2-amino-8-hydroxyquinoline. S3. Weigh acrylic acid grafted with 2-amino-8-hydroxyquinoline, 3-glycidyl etheroxypropyltrimethoxysilane and methanol according to a mass ratio of 1:4.4:20. Add the acrylic acid grafted with 2-amino-8-hydroxyquinoline and 3-glycidyl etheroxypropyltrimethoxysilane to methanol, preheat to 75°C, and then add N,N-diisopropylethylamine with a mass of 0.75 times that of the acrylic acid grafted with 2-amino-8-hydroxyquinoline. Stir and reflux for 7 hours. After the reaction is completed, cool to 25°C, remove methanol by rotary evaporator, wash the product three times with ethyl acetate, filter after washing, and dry the filtered product to obtain the polymer monomer. S4. Weigh the polymer monomer, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid according to a mass ratio of 10:30:50. Add the above three raw materials to deionized water with a mass of 10 times that of the polymer monomer. After the addition is complete, heat to 75°C. After the heating is complete, add dropwise a 10% ammonium persulfate solution with a mass of 3.4 times that of the polymer monomer and a 10% ferrous sulfate solution with a mass of 8.5 times that of the polymer monomer. After the addition is complete, keep the reaction at the temperature for 2 hours. After the reaction is complete, cool to 25°C to obtain the phosphorus-free reverse osmosis antiscalant.
[0017] Example 2 S1. Weigh hydroxyethyl acrylate, acetyl chloride and triethylamine according to a mass ratio of 2.35:2.5:1. Add hydroxyethyl acrylate and triethylamine dropwise to acetyl chloride at a temperature of 2.5℃. After the addition is complete, react at a temperature of 12.5℃ for 1.25 h. After the reaction is complete, filter and collect the filtrate. Then, remove the diethyl ether and unreacted acetyl chloride by rotary evaporation to obtain diethyl acetate acrylate. S2. Formaldehyde and 2-amino-8-hydroxyquinoline were added to ethanol at a mass ratio of 1:3.75, which was 3.5 times the mass of 2-amino-8-hydroxyquinoline. The pH of the system was adjusted to 4.5 using a 5% hydrochloric acid solution, and the mixture was refluxed at 77.5°C for 2.75 h. Then, diethyl acetate acrylate was added dropwise at a mass ratio of 1.35 times the mass of 2-amino-8-hydroxyquinoline, and the mixture was refluxed at 77.5°C for another 1.75 h. After the reaction was completed, the mixture was extracted with diethyl ether, and impurities were removed by rotary evaporation to obtain acrylic acid-grafted 2-amino-8-hydroxyquinoline. S3. Weigh acrylic acid-grafted 2-amino-8-hydroxyquinoline, 3-glycidyl etheroxypropyltrimethoxysilane, and methanol according to a mass ratio of 1:4.5:22.5. Add the acrylic acid-grafted 2-amino-8-hydroxyquinoline and 3-glycidyl etheroxypropyltrimethoxysilane to methanol, preheat to 80°C, and then add N,N-diisopropylethylamine at a mass ratio of 0.775 times that of the acrylic acid-grafted 2-amino-8-hydroxyquinoline. Stir and reflux for 8 hours. After the reaction is completed, cool to 30°C, remove methanol using a rotary evaporator, wash the product four times with ethyl acetate, filter after washing, and dry the filtered product to obtain the polymer monomer. S4. Weigh the polymer monomer, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid according to a mass ratio of 10:35:55. Add the above three raw materials to deionized water with a mass ratio of 12.5 times that of the polymer monomer. After the addition is complete, heat to 80°C. After the heating is complete, add dropwise a 10% ammonium persulfate solution with a mass ratio of 3.5 times that of the polymer monomer and a 10% ferrous sulfate solution with a mass ratio of 8.75 times that of the polymer monomer. After the addition is complete, keep the reaction at the temperature for 2.25 hours. After the reaction is complete, cool to 30°C to obtain the phosphorus-free reverse osmosis antiscalant.
[0018] Example 3 S1. Weigh hydroxyethyl acrylate, acetyl chloride and triethylamine according to a mass ratio of 2.5:2.6:1. Add hydroxyethyl acrylate and triethylamine dropwise to acetyl chloride at a temperature of 5℃. After the addition is complete, react at a temperature of 15℃ for 1.5h. After the reaction is complete, filter and collect the filtrate. Then, remove the diethyl ether and unreacted acetyl chloride by rotary evaporation to obtain diethyl acetate acrylate. S2. Formaldehyde and 2-amino-8-hydroxyquinoline were added to ethanol at a mass ratio of 1:4, which was 4 times the mass of 2-amino-8-hydroxyquinoline. The pH of the system was adjusted to 5 using a 5% hydrochloric acid solution, and the mixture was refluxed at 80°C for 3 hours. Then, diethyl acetate acrylate was added dropwise at a mass ratio of 1.5 times the mass of 2-amino-8-hydroxyquinoline, and the mixture was refluxed at 80°C for another 2 hours. After the reaction was completed, the mixture was extracted with diethyl ether, and impurities were removed by rotary evaporation to obtain acrylic acid-grafted 2-amino-8-hydroxyquinoline. S3. Weigh acrylic acid-grafted 2-amino-8-hydroxyquinoline, 3-glycidyl etheroxypropyltrimethoxysilane, and methanol according to a mass ratio of 1:4.6:25. Add the acrylic acid-grafted 2-amino-8-hydroxyquinoline and 3-glycidyl etheroxypropyltrimethoxysilane to methanol, preheat to 85°C, and then add N,N-diisopropylethylamine at a mass ratio of 0.8 times that of the acrylic acid-grafted 2-amino-8-hydroxyquinoline. Stir and reflux for 9 hours. After the reaction is completed, cool to 35°C, remove methanol using a rotary evaporator, wash the product 5 times with ethyl acetate, filter after washing, and dry the filtered product to obtain the polymer monomer. S4. Weigh the polymer monomer, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid according to a mass ratio of 10:40:60. Add the above three raw materials to deionized water with a mass ratio of 15 times that of the polymer monomer. After the addition is complete, heat to 85°C. After the heating is complete, add dropwise a 10% ammonium persulfate solution with a mass ratio of 3.6 times that of the polymer monomer and a 10% ferrous sulfate solution with a mass ratio of 9 times that of the polymer monomer. After the addition is complete, keep the reaction at the temperature for 2.5 hours. After the reaction is complete, cool to 35°C to obtain the phosphorus-free reverse osmosis antiscalant.
[0019] Example 4 The difference from Example 2 lies only in step S3: Acrylic acid grafted with 2-amino-8-hydroxyquinoline, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid are weighed according to a mass ratio of 10:35:55. These three raw materials are added to deionized water at a mass ratio of 12.5 times that of the monomers. After the addition is complete, the temperature is raised to 80°C. After the temperature is raised, a 10% ammonium persulfate solution at a mass ratio of 3.5 times that of the monomers and a 10% ferrous sulfate solution at a mass ratio of 8.75 times that of the monomers are added dropwise. After the addition is complete, the reaction is maintained at this temperature for 2.25 hours. After the reaction is complete, the temperature is cooled to 30°C to obtain a phosphorus-free reverse osmosis antiscalant. Example 5 The difference from Example 2 lies in step S3: Diethyl acetate, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid are weighed according to a mass ratio of 10:35:55. The above three raw materials are added to deionized water at a mass ratio of 12.5 times that of the monomer. After the addition is completed, the temperature is raised to 80°C. After the temperature is raised, a 10% ammonium persulfate solution at a mass ratio of 3.5 times that of the monomer and a 10% ferrous sulfate solution at a mass ratio of 8.75 times that of the monomer are added dropwise. After the addition is completed, the reaction is kept at the temperature for 2.25 hours. After the reaction is completed, the temperature is cooled to 30°C to obtain a phosphorus-free reverse osmosis antiscalant. Performance testing: Calcium carbonate scale inhibition experiments were conducted according to GB / T16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". In Ca... 2+ Concentration of 240 mg / L, CO32- In a solution with a concentration of 380 mg / L, the phosphorus-free reverse osmosis antiscalant samples prepared in Examples 1-5 were added at a dosage of 10 ppm. The solution was then allowed to stand at 60°C for 10 hours. The blank group did not contain any antiscalant sample. After cooling to room temperature, the solution was filtered, and the Ca content in the filtrate was determined by EDTA titration. 2+ The concentration was tested, and the scale inhibition rate was calculated using the following formula: Where T is the scale inhibition rate; K0 is the Ca in the original solution. 2+ Concentration; K1 is the Ca concentration in the filtrate of the blank group. 2+ Concentration; K2 is the Ca in the filtrate after treatment with the scale inhibitor sample. 2+ concentration.
[0020] To simulate the water quality conditions of typical high-salinity wastewater after reverse osmosis concentration, a fixed amount of standardized ferric oxide particles was added to this high ionic strength medium, along with 10 ppm of the phosphorus-free reverse osmosis antiscalant from Examples 1-5. The solutions were allowed to stand at room temperature (25±0.5℃) for 24 hours to ensure the system reached quasi-equilibrium. The turbidity of the supernatant was then measured using a turbidimeter. The turbidity value was positively correlated with the concentration of stable suspended fine particles in the solution; a higher turbidity value after standing indicated a stronger ability of the antiscalant to inhibit particle sedimentation and aggregation. The test results are shown in Table 1 below. Table 1 Performance Test Results Examples 1-3 all exhibited excellent calcium carbonate scale inhibition and particle dispersion performance. Among them, Example 2 had the best overall performance, with a calcium carbonate scale inhibition rate of 96.92% and a turbidity value of 73 NTU in high-salt systems. It combined scale inhibition efficiency with dispersion stability, demonstrating highly efficient scale-forming ion chelation ability, excellent particle dispersion effect and excellent adaptability to high-salt conditions.
[0021] The scale inhibition and dispersion performance of Example 4 was significantly worse than that of Example 2. Its calcium carbonate scale inhibition rate decreased by approximately 5.6 percentage points compared to Example 2, and its turbidity value decreased by 7 NTU compared to Example 2. The core reason is that Example 4 did not introduce 3-glycidyl etheroxypropyltrimethoxysilane for ring-opening graft modification, but only used acrylic acid grafted with 2-amino-8-hydroxyquinoline to participate in the polymerization. The dispersion enhancement and interfacial stabilization effect of silane groups were missing, and it was impossible to construct a chelation-dispersion synergistic system. At the same time, the lack of steric hindrance dispersion effect of silane on particulate matter significantly weakened its ability to inhibit scale-forming ions and prevent particulate agglomeration, ultimately leading to a decrease in scale inhibition rate and deterioration in dispersion stability.
[0022] Example 5 exhibited the worst scale inhibition and dispersion performance among all groups, with a calcium carbonate scale inhibition rate of only 83.77%, a decrease of approximately 13.15 percentage points compared to Example 2. Its turbidity value was only 54 NTU, a decrease of 19 NTU compared to Example 2, indicating a significantly lower overall performance than Example 2. This is because Example 5 did not prepare a polymer monomer grafted with acrylic acid and silane; it only used diethyl acetate acrylate for polymerization. Lacking the strong metal chelating active site of the 2-amino-8-hydroxyquinoline group and the core dispersion function of the silane group, it relied solely on the basic scale inhibition effects of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid. The scale-forming ion chelating ability was insufficient, resulting in extremely poor particle dispersion and the inability to form a highly efficient scale inhibition-dispersion synergistic system. Ultimately, this led to a significant decrease in the calcium carbonate scale inhibition rate and a comprehensive deterioration in particle dispersion stability under high-salt conditions.
[0023] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.
Claims
1. A phosphorus-free reverse osmosis antiscalant, its preparation method, and its application, characterized in that, The phosphorus-free reverse osmosis antiscalant is first prepared by grafting diethyl acetate acrylate and 2-amino-8-hydroxyquinoline as reactants via a Mannich base reaction to obtain an intermediate product, acrylic acid-grafted 2-amino-8-hydroxyquinoline. Subsequently, the prepared acrylic acid-grafted 2-amino-8-hydroxyquinoline is subjected to a ring-opening reaction with 3-glycidyl etheroxypropyltrimethoxysilane, and after complete reaction, a polymer monomer is obtained. Finally, using the polymer monomer, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid as polymerization reactants, the target product, the phosphorus-free reverse osmosis antiscalant, is obtained through a polymerization reaction.
2. The phosphorus-free reverse osmosis antiscalant according to claim 1, characterized in that, The mass ratio of the polymer monomer, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid is 10:30~40:50~60.
3. A method for preparing a phosphorus-free reverse osmosis antiscalant, applied to the phosphorus-free reverse osmosis antiscalant described in any one of claims 1-2, characterized in that, The phosphorus-free reverse osmosis antiscalant comprises the following preparation steps: Polymer monomers, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid are weighed according to a mass ratio of 10:30~40:50~60. These three raw materials are added to deionized water at a mass ratio of 10~15 times that of the polymer monomers. After the addition is complete, the temperature is raised to 75~85℃. After the temperature is raised, a 10% ammonium persulfate solution at a mass ratio of 3.4~3.6 times that of the polymer monomers and a 10% ferrous sulfate solution at a mass ratio of 8.5~9 times that of the polymer monomers are added dropwise. After the addition is complete, the reaction is maintained at this temperature for 2~2.5 hours. After the reaction is complete, the temperature is cooled to 25~35℃ to obtain the phosphorus-free reverse osmosis antiscalant.
4. The method for preparing the phosphorus-free reverse osmosis antiscalant according to claim 3, characterized in that, The polymer monomer comprises the following preparation steps: 2-amino-8-hydroxyquinoline grafted with acrylic acid and 3-glycidyl etheroxypropyltrimethoxysilane are added to methanol, preheated to 75-85°C, and then N,N-diisopropylethylamine, with a mass of 0.75-0.8 times that of 2-amino-8-hydroxyquinoline grafted with acrylic acid, is added. The mixture is stirred and refluxed for 7-9 hours. After the reaction is completed, the mixture is cooled to 25-35°C, methanol is removed by rotary evaporator, and the product is washed 3-5 times with ethyl acetate. After washing, the product is filtered and dried to obtain the polymer monomer.
5. The method for preparing the phosphorus-free reverse osmosis antiscalant according to claim 4, characterized in that, The preparation steps of the acrylic acid grafted 2-amino-8-hydroxyquinoline are as follows: formaldehyde and 2-amino-8-hydroxyquinoline are added to ethanol at a mass ratio of 1:3.5~4, which is 3~4 times the mass of 2-amino-8-hydroxyquinoline. The pH of the system is adjusted to 4~5 using a 5% hydrochloric acid solution, and the reaction is refluxed at 75~80℃ for 2.5~3h. Then, diethyl acetate of acrylate is added dropwise at a mass ratio of 1.2~1.5 times the mass of 2-amino-8-hydroxyquinoline, and the reaction is refluxed at 75~80℃ for 1.5~2h. After the reaction is completed, the mixture is extracted with diethyl ether, and then impurities are removed by rotary evaporation to obtain acrylic acid grafted 2-amino-8-hydroxyquinoline.
6. The method for preparing the phosphorus-free reverse osmosis antiscalant according to claim 3, characterized in that, The preparation steps of the diethyl acetate acrylate are as follows: hydroxyethyl acrylate and triethylamine are added dropwise to acetyl chloride at a temperature of 0~5℃. After the addition is complete, the mixture is reacted at a temperature of 10~15℃ for 1~1.5h. After the reaction is completed, the mixture is filtered and the filtrate is collected. Then, diethyl ether and unreacted acetyl chloride are removed by rotary evaporation to obtain diethyl acetate acrylate.
7. The method for preparing the phosphorus-free reverse osmosis antiscalant according to claim 4, characterized in that, The mass ratio of the acrylic acid grafted with 2-amino-8-hydroxyquinoline, 3-glycidyl etheroxypropyltrimethoxysilane and methanol is 1:4.4~4.6:20~25.
8. The method for preparing the phosphorus-free reverse osmosis antiscalant according to claim 6, characterized in that, The mass ratio of hydroxyethyl acrylate, acetyl chloride and triethylamine is 2.2~2.5:2.4~2.6:
1.
9. A scale inhibitor, characterized in that, The scale inhibitor includes the phosphorus-free reverse osmosis scale inhibitor as described in claim 1 or 2.