Scale inhibitor for membrane as well as preparation method and application of scale inhibitor

Abstract

The invention discloses a scale inhibitor for a membrane as well as a preparation method and application of the scale inhibitor, and relates to the technical field of water treatment chemicals. The scale inhibitor for the membrane at least comprises organic phosphonic acid and a carboxylic acid polymer, the carboxylic acid polymer comprises a carboxylic acid nano spherical polymer which is obtained by grafting acrylic acid and a modified monomer on the surface of a polystyrene core; the modified monomer is a chemical bond product of methacryloyl chloride and pyridinium hydroxy propyl sulfobetaine. According to the scale inhibitor prepared by the invention, all the component compounds are compounded to play a synergistic role, so that the scale inhibitor has a better scale inhibition effect; in addition, the corrosion inhibition capability is greatly improved, and the effect of multiple effects by one agent is achieved; meanwhile, the prepared scale inhibitor is more long-acting in scale inhibition performance, and stable operation of a reverse osmosis membrane system can be better maintained.

Description

Technical Field

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

[0002] Membrane separation technology has been widely used in the water treatment industry. It can remove a wide range of impurities from water, including inorganic matter, metal ions, organic matter, colloids, and even bacteria and viruses. It is a highly efficient, low-energy, and pollution-free new water treatment technology. Reverse osmosis membrane separation technology offers advantages such as no phase change, modularity, simple process flow, convenient operation, small footprint, low investment, and low power consumption. It continues to have broad application prospects in industrial water treatment. Membrane fouling is a significant factor affecting the efficiency and lifespan of osmosis systems. During the osmotic water treatment process, membrane fouling can accumulate over time, leading to reduced osmosis efficiency and, in severe cases, requiring immediate replacement of the reverse osmosis membrane. Research has been conducted on the causes of membrane fouling, and membrane fouling can be categorized into inorganic and organic scale. Scale types can be categorized as particulate, colloidal, or microbial. Particulate scale is addressed through flocculants, precipitation, and filtration. Microbial scale is addressed through the addition of biocides. Inorganic scale is addressed through the addition of scale inhibitors. Antiscalants with good performance can inhibit the formation of scale, extend the service life of the osmotic membrane, and thus reduce the operating costs of the osmotic system.

[0003] Currently, commonly used corrosion and scale inhibitors generally consist of organic phosphines, copolymers, and corrosion inhibitors. Despite their wide variety, traditional agent design methods rarely involve research on reverse osmosis inhibition mechanisms. Consequently, selectivity for corrosion and scale inhibitors specifically targeting reverse osmosis systems is extremely limited. However, reverse osmosis membranes, due to their small pore size and susceptibility to fouling, require unique, proprietary corrosion and scale inhibitor formulations. This has led to China's current reliance on imports for chemicals used in reverse osmosis membranes. There is no established domestic market for specialized corrosion and scale inhibitors for reverse osmosis, necessitating the development of domestically produced corrosion and scale inhibitors for reverse osmosis membranes. Summary of the Invention

[0004] The purpose of the present invention is to provide a membrane scale inhibitor and its preparation method and application. The component compounds of the scale inhibitor are compounded to exert a synergistic effect and have a better scale inhibition effect; and the corrosion inhibition ability is greatly improved, showing a one-dose multi-effect effect; at the same time, the prepared scale inhibitor has a longer-lasting scale inhibition performance and can better maintain the stable operation of the reverse osmosis membrane system.

[0005] The technical solutions adopted by the present invention to achieve the above-mentioned purpose are: A membrane scale inhibitor comprising at least an organic phosphonic acid and a carboxylic acid polymer; The carboxylic acid polymers described above include carboxylic acid nano-spherical polymers obtained by grafting acrylic acid and a modified monomer onto the surface of a polystyrene core; the modified monomer is a chemically bonded product of methacryloyl chloride and hydroxypropanesulfonic acid pyridinium salt. The present invention successfully prepares novel carboxylic acid nano-spherical polymers having a core-shell structure, regular morphology, uniform particle size, and excellent dispersibility through emulsion polymerization and photoemulsion polymerization. These polymers exhibit superior scale inhibition capabilities. Application of these polymers in the preparation of membrane scale inhibitors significantly enhances the scale inhibition effect of the scale inhibitor against calcium sulfate and calcium phosphate scales, while also providing superior corrosion inhibition. These polymers effectively extend the service life of the scale inhibitor, better maintaining the operational stability of system devices and possess broad application prospects. The reason for this may be that the surface of the nanospheres is chemically modified using a chemically bonded product of methacryloyl chloride and pyridinium hydroxypropanesulfonate as a modifying monomer, introducing more active functional groups onto their surface. Through electrostatic interactions and other effects, these groups are more conducive to complexing metal ions such as calcium, magnesium, and aluminum ions, and evenly dispersing them in water, effectively increasing the solubility of insoluble salts such as calcium carbonate and calcium sulfate. Furthermore, the steric hindrance of the chain structure may effectively hinder the crystallization of inorganic salts, inhibiting the formation and precipitation of scale, and achieving a better scale inhibition effect. At the same time, the active functional groups on their surface can be adsorbed on metal surfaces through chemical adsorption and other methods, forming a protective adsorption film, thereby slowing down corrosion on the metal surface and enhancing the corrosion inhibition ability of the scale inhibitor. By combining the various components of the scale inhibitor, a synergistic effect is exerted, and their chelating properties, solubilizing ability, lattice distortion, and electronegativity are fully utilized, resulting in a better scale inhibition effect on various insoluble substances in water. Furthermore, a single agent has multiple effects, addressing both corrosion and scaling problems simultaneously.

[0006] In a specific embodiment, the average particle size of the carboxylic acid polymer is 100-150 nm.

[0007] In a specific embodiment, the method for preparing a carboxylic acid polymer comprises: (1) The modified monomer was prepared by Schotten-Baumann reaction using hydroxypropanesulfonic acid pyridinium salt and methacryloyl chloride as raw materials; (2) Preparation of polystyrene core encapsulated with photoinitiator by emulsion polymerization; (3) Ultraviolet light is used to initiate free radicals to graft acrylic monomers and modified monomers onto the polystyrene core.

[0008] More specifically, the preparation method of the above-mentioned carboxylic acid polymer comprises the following steps: (1) Take hydroxypropanesulfonic acid pyridinium salt and add acetone to dissolve it. Add catalyst pyridine under ice bath conditions, then slowly add methacryloyl chloride acetone solution using a constant pressure dropping funnel. After the addition is complete, remove the ice bath and continue the reaction for 10-12 hours. Pay attention to protect the reaction from light throughout the process; then, remove the organic solvent by rotary evaporation and purify by silica gel column chromatography to obtain the modified monomer; (2) Take the emulsifier SDS and the initiator KPS, dissolve them in deionized water with ultrasound, add styrene, stir, fill with nitrogen to deoxygenate, and then heat to 78~84℃ under nitrogen protection for 1~2h; then cool to 68~72℃, slowly add the acetone solution of the photoinitiator 2-(p-2-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate, keep it stable after the addition is completed, and continue to react for 0.5~1.5h, filter, and dialyze with deionized water in a dialysis bag to obtain a polystyrene core emulsion with a solid content of 2~4%; (3) Take the polystyrene core emulsion, add acrylic acid monomer and modified monomer, add deionized water, and react under nitrogen protection with ultraviolet light for 2-3 hours. Then dialyze with a dialysis bag, rotary evaporate, and freeze-dry to obtain a carboxylic acid polymer.

[0009] In a specific embodiment, in step (1), the solid-liquid ratio of hydroxypropanesulfonic acid pyridinium salt to acetone is 0.15-0.25 g:1 mL; the mass ratio of catalyst pyridine to hydroxypropanesulfonic acid pyridinium salt is 0.3-0.4:1; the concentration of methacryloyl chloride in acetone solution is 0.2-0.3 g / mL; and the molar ratio of hydroxypropanesulfonic acid pyridinium salt to methacryloyl chloride is 1:1-1.1.

[0010] In a specific embodiment, in step (2), the mass ratio of emulsifier SDS to initiator KPS is 1:2.5~3.5; the solid-liquid ratio of emulsifier SDS to deionized water is 0.5~1 mg:1 mL; the mass ratio of styrene to emulsifier SDS is 45~55:1; the concentration of the acetone solution of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate is 8~12wt%; and the amount of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate added is 1~3wt% of styrene.

[0011] In a specific embodiment, in step (3), the mass ratio of the polystyrene core emulsion to the acrylic acid monomer is 1:0.5-0.8; and the molar ratio of the acrylic acid monomer to the modified monomer is 1:0.3-0.5.

[0012] In a specific embodiment, the organic phosphonic acid is selected from one of diethylenetriaminepentamethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, and hydroxyethylidene diphosphonic acid.

[0013] In a specific embodiment, the membrane scale inhibitor further comprises acrylic acid copolymer, polyepoxysuccinic acid, and polymaleic acid.

[0014] In a specific embodiment, the membrane scale inhibitor includes, by weight, 5 to 10 parts of organic phosphonic acid, 3 to 5 parts of acrylic copolymer, 3 to 5 parts of polyepoxysuccinic acid, 2 to 4 parts of carboxylic acid polymer, 2 to 5 parts of polymaleic acid, 1 to 3 parts of tetrasodium ethylenediaminetetraacetic acid, 0.2 to 1.5 parts of isothiazolinone, 0.5 to 1 part of sodium hydroxide, and 60 to 80 parts of water.

[0015] Preferably, the polyepoxysuccinic acid is replaced by a modified polyepoxysuccinic acid, wherein the modifying agent used for the modified polyepoxysuccinic acid comprises thiourea dioxide.

[0016] More preferably, the above-mentioned modifier also includes 3-amino-5-mercapto-1,2,4-triazole. The present invention uses 3-amino-5-mercapto-1,2,4-triazole to modify polyepoxysuccinic acid to prepare modified polyepoxysuccinic acid, and its scale inhibition performance is significantly improved, effectively improving the inhibitory effect of modified polyepoxysuccinic acid on crystal nucleation, prolonging the nucleation induction period of calcium carbonate crystals, and thus more effectively preventing the formation of calcium carbonate scale; applying it to the preparation process of membrane scale inhibitors, and synergistically compounding with other components can further enhance the scale inhibition ability of the scale inhibitor, and improve the corrosion inhibition effect of the scale inhibitor, further inhibiting the corrosion rate of carbon steel, flavonoids and stainless steel materials; at the same time, it can effectively extend the service life of the scale inhibitor and maintain the long-term stable operation of the reverse osmosis membrane system device. The reason may be that 3-amino-5-mercapto-1,2,4-triazole and thiourea dioxide are used to modify polyepoxysuccinic acid, and the introduction of atoms such as O and N can react with Ca in the aqueous solution. 2+ Mg 2+ 、Ba 2+ The metal ions form stable complexes, effectively reducing the Ca 2+ The concentration of plasma reduces the possibility of precipitation of calcium carbonate, calcium sulfate and calcium phosphate scale, and may also form a double electric layer structure on the surface of calcium carbonate microcrystals through physical / chemical adsorption, so that electrostatic repulsion is generated between the crystals, hindering the formation of larger crystals, showing more excellent scale inhibition performance, and can effectively control the large-scale scaling of salts on the reverse osmosis membrane, thereby significantly reducing the cleaning frequency of the reverse osmosis system and maintaining normal operation.

[0017] The present invention also discloses a method for preparing the modified polyepoxysuccinic acid, comprising: Polyepoxysuccinic acid was dissolved in water and the pH was adjusted to neutral. Thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole were added under 80-90°C oil bath conditions and reacted for 1-2 hours. The modified polyepoxysuccinic acid was obtained by vacuum distillation, dialysis with a dialysis bag, rotary evaporation, and vacuum drying.

[0018] In a specific embodiment, the solid-liquid ratio of polyepoxysuccinic acid to water is 0.02~0.03g:1mL; the mass ratio of polyepoxysuccinic acid to thiourea dioxide is 1:0.4~0.6; and the molar ratio of thiourea dioxide to 3-amino-5-mercapto-1,2,4-triazole is 1:0.2~0.4.

[0019] In a specific embodiment, the molecular weight of the modified polyepoxysuccinic acid is 500-700.

[0020] The invention further discloses a preparation method of the membrane scale inhibitor, which comprises: taking various raw materials in parts by weight and mixing them uniformly to obtain the membrane scale inhibitor.

[0021] The invention also discloses application of the scale inhibitor in water treatment based on a reverse osmosis membrane.

[0022] In specific embodiments, water treatment includes brackish water treatment, grey water treatment, or seawater treatment.

[0023] Another object of the present invention is to provide a method for preventing scale of a reverse osmosis membrane, wherein the aforementioned membrane antiscalant is added to a reverse osmosis system.

[0024] Compared with the prior art, the present invention has the following beneficial effects: The present invention successfully prepares a new type of carboxylic acid nano-spherical polymer through emulsion polymerization and photoemulsion polymerization, which exhibits more excellent scale inhibition ability. When applied to the preparation process of membrane scale inhibitors, it can significantly enhance the scale inhibition effect of the scale inhibitor on calcium sulfate scale and calcium phosphate scale, while also having a more excellent corrosion inhibition effect and effectively extending the service life of the scale inhibitor. In addition, the present invention uses 3-amino-5-mercapto-1,2,4-triazole to modify polyepoxysuccinic acid to prepare modified polyepoxysuccinic acid, which has significantly improved scale inhibition performance, effectively enhancing the inhibitory effect of the modified polyepoxysuccinic acid on crystal nucleation, and more effectively preventing the formation of calcium carbonate scale; when applied to the preparation process of membrane scale inhibitors and synergistically compounded with other components, it can further enhance the scale inhibition ability of the scale inhibitor, improve the corrosion inhibition effect of the scale inhibitor, further inhibit the corrosion rate of carbon steel, flavonoids and stainless steel materials; and effectively extend the service life of the scale inhibitor. The membrane scale inhibitor provided by the present invention exerts a synergistic effect through the compounding of the component compounds, and its chelating property, solubilizing ability, lattice distortion and electronegativity are fully exerted, which has a better scale inhibition effect on various insoluble substances in water; and one agent has multiple effects and can solve the problems of corrosion and scaling at the same time.

[0025] Therefore, the present invention provides a membrane scale inhibitor, a preparation method and an application thereof. The component compounds of the scale inhibitor are compounded to exert a synergistic effect and have a better scale inhibition effect; and the corrosion inhibition ability is greatly improved, showing a one-dose multi-effect effect; at the same time, the prepared scale inhibitor has a longer-lasting scale inhibition performance and can better maintain the stable operation of the reverse osmosis membrane system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The infrared spectrum test results of the polystyrene core and the carboxylic acid polymer in Example 1 of the present invention are as follows; Figure 2 The infrared spectrum test results of the modified polyepoxysuccinic acid and polyepoxysuccinic acid in Example 5 of the present invention are shown; Figure 3 TEM test results of the carboxylic acid polymer in Example 1 of the present invention; Figure 4 The scale inhibition ability test results of modified polyepoxysuccinic acid in the test examples of the present invention are as follows; Figure 5 The scale inhibition ability test results of the membrane scale inhibitor in the test example of the present invention are shown in FIG. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments: The photoinitiator 2-(p-2-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate used in the embodiments of the present invention is prepared according to the prior art, and is synthesized from 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone and methacryloyl chloride as raw materials through the Schotten-Baumann reaction.

[0028] Example 1: A scale inhibitor for a membrane comprises, by weight, 8 parts of diethylenetriaminepentamethylenephosphonic acid, 4 parts of acrylic acid copolymer, 4 parts of polyepoxysuccinic acid, 3 parts of carboxylic acid polymer, 3 parts of polymaleic acid, 2 parts of tetrasodium ethylenediaminetetraacetate, 1 part of isothiazolinone, 0.8 parts of sodium hydroxide, and 70 parts of water.

[0029] The preparation method of the membrane scale inhibitor is as follows: the raw materials are mixed uniformly according to weight to obtain the membrane scale inhibitor.

[0030] Preparation of carboxylic acid polymers: (1) Take hydroxypropanesulfonic acid pyridinium salt and dissolve it in acetone (solid-liquid ratio is 0.21g:1mL), add catalyst pyridine under ice bath condition, and the mass ratio of pyridine to hydroxypropanesulfonic acid pyridinium salt is 0.36:1; then slowly add methacryloyl chloride acetone solution (concentration 0.25g / mL) using constant pressure dropping funnel, wherein the molar ratio of hydroxypropanesulfonic acid pyridinium salt to methacryloyl chloride is 1:1.05; after the addition is completed, remove the ice bath and continue the reaction for 12h, paying attention to the light protection during the reaction process; then remove the organic solvent by rotary evaporation, and purify by silica gel column chromatography (eluent chloroform: acetone = 5:1, v / v) to obtain the modified monomer. 1 HNMR(400 MHz, Acetone-d6) δ: 8.76, 8.68, 8.19 (5H, Py-H), 6.52, 6.33(2H, C=CH2), 5.40, 5.15(m, 2H, -CH2), 4.74(m, 1H, -CH), 3.79, 3.48(m, 2H, -CH2), 1.97(s, 3H,-CH3); (2) Take emulsifier SDS and initiator KPS in a mass ratio of 1:3.1, ultrasonically dissolve them in deionized water (the solid-liquid ratio of emulsifier SDS to deionized water is 0.8 mg:1 mL), add styrene (the mass ratio of styrene to emulsifier SDS is 50.5:1), stir, fill with nitrogen to deoxygenate, and then heat to 80°C under nitrogen protection for 1.5 hours; then cool to 70°C, and slowly add the acetone solution of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate (concentration 10.2wt%), the amount of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate added is 2.1wt% of styrene; after the addition is completed, keep it stable and continue to react for 1 hour, filter, and dialyze with deionized water in a dialysis bag to obtain a polystyrene core emulsion with a solid content of 3.2%; (3) Take polystyrene core emulsion, add acrylic acid monomer and modified monomer, add deionized water, and react under nitrogen protection with ultraviolet light for 2.5 hours. Then dialyze with a dialysis bag, rotary evaporate, and freeze-dry to obtain a carboxylic acid polymer (average particle size of 136 nm). In the specific experimental process, the mass ratio of polystyrene core emulsion to acrylic acid monomer was 1:0.68; the molar ratio of acrylic acid monomer to modified monomer was 1:0.41.

[0031] Example 2: A scale inhibitor for a membrane comprises, by weight, 5 parts of hexamethylenediaminetetramethylenephosphonic acid, 5 parts of acrylic acid copolymer, 3 parts of polyepoxysuccinic acid, 2 parts of carboxylic acid polymer, 3 parts of polymaleic acid, 1 part of tetrasodium ethylenediaminetetraacetate, 0.2 parts of isothiazolinone, 0.5 parts of sodium hydroxide, and 60 parts of water.

[0032] The preparation of the membrane antiscalant is the same as that in Example 1.

[0033] The preparation of the carboxylic acid polymer differs from that of Example 1 in that: The mass ratio of catalyst pyridine to hydroxypropanesulfonic acid pyridinium salt is 0.3:1; the concentration of methacryloyl chloride in acetone solution is 0.2 g / mL; the molar ratio of hydroxypropanesulfonic acid pyridinium salt to methacryloyl chloride is 1:1; The mass ratio of emulsifier SDS to initiator KPS is 1:2.5; the mass ratio of styrene to emulsifier SDS is 48:1; the concentration of the acetone solution of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate is 9wt%; the amount of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate added is 1.2wt% of styrene; The mass ratio of polystyrene core emulsion to acrylic acid monomer is 1:0.5; the molar ratio of acrylic acid monomer to modifying monomer is 1:0.3; The average particle size of the carboxylic acid polymer is 109 nm.

[0034] Example 3: A scale inhibitor for a membrane comprises, by weight, 10 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, 3 parts of acrylic acid copolymer, 4 parts of polyepoxysuccinic acid, 4 parts of carboxylic acid polymer, 2 parts of polymaleic acid, 2 parts of tetrasodium ethylenediaminetetraacetate, 0.5 parts of isothiazolinone, 1 part of sodium hydroxide, and 76 parts of water.

[0035] The preparation of the membrane antiscalant is the same as that in Example 1.

[0036] The preparation of the carboxylic acid polymer differs from that of Example 1 in that: The mass ratio of catalyst pyridine to hydroxypropanesulfonic acid pyridinium salt is 0.4:1; the concentration of methacryloyl chloride in acetone solution is 0.3 g / mL; the molar ratio of hydroxypropanesulfonic acid pyridinium salt to methacryloyl chloride is 1:1.1; The mass ratio of emulsifier SDS to initiator KPS was 1:3.5; the mass ratio of styrene to emulsifier SDS was 55:1; the concentration of the acetone solution of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate was 11.5wt%; the amount of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate added was 2.6wt% of styrene; The mass ratio of polystyrene core emulsion to acrylic acid monomer is 1:0.8; the molar ratio of acrylic acid monomer to modifying monomer is 1:0.5; The average particle size of the carboxylic acid polymer is 142 nm.

[0037] Example 4: A scale inhibitor for a membrane comprises, by weight, 7 parts of hydroxyethylidene diphosphonic acid, 5 parts of acrylic acid copolymer, 3 parts of polyepoxysuccinic acid, 4 parts of carboxylic acid polymer, 3 parts of polymaleic acid, 3 parts of tetrasodium ethylenediaminetetraacetate, 0.7 parts of isothiazolinone, 1 part of sodium hydroxide, and 72 parts of water.

[0038] The preparation of the membrane antiscalant is the same as that in Example 1.

[0039] The preparation of the carboxylic acid polymer differs from that of Example 1 in that: The mass ratio of catalyst pyridine to hydroxypropanesulfonic acid pyridinium salt is 0.33:1; the concentration of methacryloyl chloride in acetone solution is 0.23 g / mL; the molar ratio of hydroxypropanesulfonic acid pyridinium salt to methacryloyl chloride is 1:1.08; The mass ratio of emulsifier SDS to initiator KPS is 1:3.3; the mass ratio of styrene to emulsifier SDS is 47:1; the concentration of the acetone solution of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate is 9.5wt%; the amount of photoinitiator 2-(p-hydroxy-2-methylpropiophenone)-hydroxyethyl methacrylate added is 1.8wt% of styrene; The mass ratio of polystyrene core emulsion to acrylic acid monomer is 1:0.61; the molar ratio of acrylic acid monomer to modifying monomer is 1:0.37; The average particle size of the carboxylic acid polymer is 122 nm.

[0040] Example 5: The difference between a membrane scale inhibitor and Example 1 is that an equal molar amount of modified polyepoxysuccinic acid is used instead of polyepoxysuccinic acid.

[0041] The preparation of the membrane antiscalant is the same as that in Example 1.

[0042] The preparation of the carboxylic acid polymer is the same as that in Example 1.

[0043] Preparation of modified polyepoxysuccinic acid: Polyepoxysuccinic acid was dissolved in water with a solid-liquid ratio of 0.025 g:1 mL, and the pH was adjusted to neutral. Thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole were added under 86°C oil bath conditions and reacted for 1.5 h. The product was distilled under reduced pressure, dialyzed with a dialysis bag, rotary evaporated, and vacuum dried to obtain modified polyepoxysuccinic acid with a molecular weight of 618.4; the mass ratio of polyepoxysuccinic acid to thiourea dioxide was 1:0.52; and the molar ratio of thiourea dioxide to 3-amino-5-mercapto-1,2,4-triazole was 1:0.32.

[0044] Example 6: The difference between a membrane scale inhibitor and Example 5 is that the modified polyepoxysuccinic acid is prepared in this example.

[0045] The preparation of the above-mentioned membrane scale inhibitor is the same as that in Example 5.

[0046] The preparation of the carboxylic acid polymer is the same as that in Example 5.

[0047] The difference between the preparation of modified polyepoxysuccinic acid and Example 5 is: Thiourea dioxide was used in an equal molar amount to replace 3-amino-5-mercapto-1,2,4-triazole.

[0048] Example 7: The difference between a membrane scale inhibitor and Example 5 is that the modified polyepoxysuccinic acid is prepared in this example.

[0049] The preparation of the above-mentioned membrane scale inhibitor is the same as that in Example 5.

[0050] The preparation of the carboxylic acid polymer is the same as that in Example 5.

[0051] The difference between the preparation of modified polyepoxysuccinic acid and Example 5 is: Thiourea dioxide was replaced by an equal molar amount of 3-amino-5-mercapto-1,2,4-triazole.

[0052] Example 8: The difference between a membrane scale inhibitor and Example 5 is that the carboxylic acid polymer is prepared in this example.

[0053] The preparation of the above-mentioned membrane scale inhibitor is the same as that in Example 5.

[0054] The difference between the preparation of the carboxylic acid polymer and Example 5 is that an equimolar amount of acrylic acid is used to replace the modifying monomer.

[0055] The preparation of modified polyepoxysuccinic acid is the same as that in Example 5.

[0056] Example 9: The difference between a membrane scale inhibitor and Example 1 is that the carboxylic acid polymer is prepared in this example.

[0057] The preparation of the membrane antiscalant is the same as that in Example 1.

[0058] The difference between the preparation of the carboxylic acid polymer and Example 1 is that an equimolar amount of acrylic acid is used to replace the modifying monomer.

[0059] Test Example 1: Infrared characterization The test was performed using the potassium bromide tablet method using a Fourier transform infrared spectrometer with a wavelength range of 4000~500cm -1 .

[0060] The polystyrene core and carboxylic acid polymer prepared in Example 1 were tested as above. The results are as follows: Figure 1 As shown in the figure, compared with the infrared spectrum of polystyrene core, in the infrared test results of carboxylic acid polymer, 1709cm -1 The characteristic absorption peak of C=O appears near 1185cm -1 、610cm -1 The characteristic absorption peak of the sulfonic acid group appeared nearby, indicating that the carboxylic acid polymer in Example 1 was successfully prepared.

[0061] The modified polyepoxysuccinic acid and polyepoxysuccinic acid prepared in Example 5 were tested as above. The results are as follows: Figure 2 As shown in the figure, compared with the infrared spectrum curve of polyepoxysuccinic acid, in the infrared spectrum of modified polyepoxysuccinic acid, 1664cm -1 The characteristic absorption peak of C=O in the amide group appears near 1270 cm -1 The characteristic absorption peak of CN bond appears near 1160cm -1 The characteristic absorption peak of S=O bond appears near 1048cm -1 The characteristic absorption peak of CS bond appears near the surface, indicating that the polyepoxysuccinic acid in Example 5 was successfully prepared.

[0062] TEM characterization The carboxylic acid polymer prepared in Example 1 was subjected to TEM testing at a scanning voltage of 200 kV. The results are as follows: Figure 3 As shown in the figure, it can be seen that the carboxylic acid polymer prepared in Example 1 presents a relatively regular spherical shape and exhibits good dispersibility.

[0063] Test Example 2: Scale inhibition capacity determination Static method for measuring scale inhibition rate: The experimental test method is carried out in accordance with the standards specified in GB / T 16632 and the standard application guide for water treatment agents. Experimental test conditions: C (Ca 2+ ) = 400 mg / L (calculated as calcium carbonate), C (HCO3 - ) = 800 mg / L (calculated as calcium carbonate), experimental temperature 60℃, time 10h. EDTA was used to determine the Ca content in the solution. 2+ Concentration. Finally, the static scale inhibition rate is calculated according to the following formula: Static scale inhibition rate = (C2-C1) / (C2-C0)×100% Where C0 represents the calcium ion content of the supernatant without adding scale inhibitor, mg / L; C1 represents the calcium ion content of the supernatant with adding scale inhibitor, mg / L; C2 represents the original calcium ion content of the experimental water sample, mg / L.

[0064] The modified polyepoxysuccinic acid prepared in Examples 5 to 7 was subjected to the above test with an addition concentration of 3.5 mg / L. The results are as follows: Figure 4 As shown in the figure, it can be seen that the scale inhibition rate of the modified polyepoxysuccinic acid prepared in Example 5 is significantly higher than that of Examples 6 and 7, and better than that of the unmodified one. In addition, the effects of Examples 6 and 7 are better than that of the unmodified one, indicating that the modification of polyepoxysuccinic acid with thiourea dioxide and / or 3-amino-5-mercapto-1,2,4-triazole can effectively improve the scale inhibition ability of the modified polyepoxysuccinic acid, and under the condition of the simultaneous presence of thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole, the scale inhibition performance of the modified polyepoxysuccinic acid is better enhanced.

[0065] Determination of the influence on the nucleation of calcium carbonate crystals The test was conducted using the conductivity method, specifically: take two dry beakers (500 mL) A and B, add equal volumes of calcium chloride solution and sodium bicarbonate solution respectively, add the sample solution to be tested to beaker A to a concentration of 8 mg / L, and do not add the sample solution to beaker B; at the same temperature, measure the conductivity in each beaker after 8 minutes.

[0066] The modified polyepoxysuccinic acid prepared in Examples 5 to 7 was subjected to the above test at an addition concentration of 3.5 mg / L. The results are shown in Table 1: Table 1 Conductivity test results

[0067] From the data analysis in Table 1, it can be seen that the conductivity of the modified polyepoxysuccinic acid prepared in Example 5 is significantly lower than that of Examples 6 and 7, and lower than that of the unmodified one, and the effects of Examples 6 and 7 are better than that of the unmodified one, indicating that the modification of polyepoxysuccinic acid by thiourea dioxide and / or 3-amino-5-mercapto-1,2,4-triazole can effectively enhance the inhibitory effect of the modified polyepoxysuccinic acid on crystal nucleation, prolong the nucleation induction period of calcium carbonate crystals, and thus more effectively prevent the formation of calcium carbonate scale; and under the condition of the simultaneous presence of thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole, the enhancement effect of the inhibitory effect of the modified polyepoxysuccinic acid on crystal nucleation is better.

[0068] Test Example 3: Determination of scale inhibition capacity of scale inhibitors 1) Determination of calcium phosphate scale resistance performance The test method is carried out in accordance with the standard specified in GB / T 22626 and is determined by spectrophotometry. The experimental principle is: orthophosphate reacts with ammonium molybdate in an acidic environment to form phosphomolybdic heteropoly acid, which is then reduced by ascorbic acid to form phosphomolybdic blue. Experimental test conditions: C (Ca 2+) = 250 mg / L (calculated as calcium carbonate), C(PO4 3- ) = 5mg / L (as PO4 3- Calculate the scale inhibition rate according to the following formula: Scale inhibition rate = (A1-A0) / (A2-A0) × 100% Wherein, A0 represents the absorbance after heating without adding scale inhibitor; A1 represents the absorbance after heating with adding scale inhibitor; A2 represents the absorbance without adding scale inhibitor and without heating.

[0069] 2) Determination of calcium sulfate scale inhibition performance Experimental test conditions: C (Ca 2+ ) = 6800 mg / L (calculated as calcium sulfate), C (SO4 2- ) = 7100 mg / L (calculated as Na2SO4). Calculate the scale inhibition rate according to the following formula: Scale inhibition rate = (C2-C1) / (C2-C0)×100% Where C0 represents the calcium ion content of the supernatant without adding scale inhibitor, mg / L; C1 represents the calcium ion content of the supernatant with adding scale inhibitor, mg / L; C2 represents the original calcium ion content of the experimental water sample, mg / L.

[0070] The above test was conducted on the membrane scale inhibitors prepared in Examples 1 to 9, with a dosage of 4 mg / L. The results are as follows: Figure 5 As shown in the figure, the scale inhibition rate of the scale inhibitor prepared in Example 1 against calcium sulfate scale and calcium phosphate scale is significantly higher than that of Example 9, indicating that the carboxylic acid polymer prepared by chemically grafting the surface of the polystyrene core with hydroxypropane pyridinium sulfonate can effectively enhance the scale inhibition ability of the scale inhibitor and has a more excellent scale inhibition effect on both calcium sulfate scale and calcium phosphate scale. The scale inhibition rate of the scale inhibitor prepared in Example 5 for calcium sulfate scale and calcium phosphate scale is significantly higher than that of Example 6 and Example 7, and better than that of Example 1, and the effects of Example 6 and Example 7 are better than that of Example 1, indicating that the modified polyepoxysuccinic acid prepared by modifying polyepoxysuccinic acid with thiourea dioxide and / or 3-amino-5-mercapto-1,2,4-triazole can effectively improve the scale inhibition ability of the scale inhibitor when used in membrane scale inhibitors, and the enhancement effect on the scale inhibition performance of the scale inhibitor is better under the condition that thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole are simultaneously present.

[0071] Corrosion inhibition performance determination The test method is carried out in accordance with the method specified in GB / T18175 "Determination of corrosion inhibition performance of water treatment agents - Rotating coupon method". The specific test conditions are: temperature 45°C, rotation speed 75r / min, and test time 72h.

[0072] The above test was performed on the membrane scale inhibitors prepared in Examples 1 to 9, with a dosage of 4 mg / L. The results are shown in Table 2: Table 2 Corrosion inhibition performance test results

[0073] Analysis of the data in Table 2 shows that the corrosion rates of carbon steel, flavonoids, and stainless steel using the scale inhibitor prepared in Example 1 were significantly lower than those in Example 9, indicating that chemical grafting modification of the polystyrene core surface with pyridinium hydroxypropanesulfonate to produce a carboxylic acid polymer can effectively enhance the corrosion inhibition capability of the scale inhibitor. The corrosion rates of carbon steel, flavonoids, and stainless steel using the scale inhibitor prepared in Example 1 were significantly lower than those in Examples 6 and 7, and lower than that in Example 1. Furthermore, the effects of Examples 6 and 7 were better than those of Example 1, indicating that the modified polyepoxysuccinic acid prepared by modifying polyepoxysuccinic acid with thiourea dioxide and / or 3-amino-5-mercapto-1,2,4-triazole can effectively improve the corrosion inhibition capability of the scale inhibitor when used in a membrane scale inhibitor. Furthermore, the enhanced corrosion inhibition performance of the scale inhibitor is even better when thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole are present simultaneously.

[0074] Device operation stability test At a plant in a certain region, the influent water had a conductivity of 3440 μs / cm, a salt content of 2108 mg / L, and an alkalinity of 315 mg / L (calcium carbonate). A 4 mg / L scale inhibitor sample was added, and the reverse osmosis unit's stable operating time was observed and recorded.

[0075] The above test was performed on the membrane scale inhibitors prepared in Examples 1 and 5 to 9. The results are shown in Table 3: Table 3 Operation stability test results

[0076] Analysis of the data in Table 3 shows that the reverse osmosis device using the scale inhibitor prepared in Example 1 maintained stable operation significantly longer than that of Example 9, indicating that chemical grafting modification of the polystyrene core surface with pyridinium hydroxypropanesulfonate to produce a carboxylic acid polymer can effectively extend the service life of the scale inhibitor. The reverse osmosis device using the scale inhibitor prepared in Example 1 maintained stable operation significantly longer than that of Examples 6 and 7, and longer than that of Example 1. Furthermore, the performance of Examples 6 and 7 was superior to that of Example 1, indicating that the modified polyepoxysuccinic acid prepared by modifying polyepoxysuccinic acid with thiourea dioxide and / or 3-amino-5-mercapto-1,2,4-triazole can effectively improve the service life of the scale inhibitor when used in a membrane scale inhibitor. Furthermore, the enhanced service life of the scale inhibitor is even greater when thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole are both present.

[0077] The conventional techniques in the above embodiments are prior arts known to those skilled in the art, and thus will not be described in detail here.

[0078] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A membrane scale inhibitor comprising at least an organic phosphonic acid and a carboxylic acid polymer; The carboxylic acid polymer includes a carboxylic acid nano-spherical polymer, which is obtained by grafting acrylic acid and a modified monomer onto the surface of a polystyrene core; the modified monomer is a chemically bonded product of methacryloyl chloride and hydroxypropanesulfonic acid pyridinium salt.

2. A membrane scale inhibitor according to claim 1, characterized in that: The average particle size of the carboxylic acid polymer is 100-150 nm.

3. The membrane scale inhibitor according to claim 1, characterized in that: The organic phosphonic acid is selected from one of diethylenetriaminepentamethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, and hydroxyethylidene diphosphonic acid.

4. The membrane scale inhibitor according to claim 1, characterized in that: The membrane scale inhibitor further comprises acrylic acid copolymer, polyepoxysuccinic acid and polymaleic acid.

5. The membrane scale inhibitor according to claim 1, characterized in that: The membrane scale inhibitor comprises, by weight, 5 to 10 parts of organic phosphonic acid, 3 to 5 parts of acrylic copolymer, 3 to 5 parts of polyepoxysuccinic acid, 2 to 4 parts of carboxylic acid polymer, 2 to 5 parts of polymaleic acid, 1 to 3 parts of tetrasodium ethylenediaminetetraacetate, 0.2 to 1.5 parts of isothiazolinone, 0.5 to 1 part of sodium hydroxide, and 60 to 80 parts of water.

6. The membrane scale inhibitor according to claim 5, characterized in that: The polyepoxysuccinic acid is replaced by modified polyepoxysuccinic acid, and the modifier used for the modified polyepoxysuccinic acid includes thiourea dioxide and 3-amino-5-mercapto-1,2,4-triazole; the molecular weight of the modified polyepoxysuccinic acid is 500-700.

7. The method for preparing the membrane scale inhibitor according to claim 1, comprising: The raw materials are mixed uniformly according to the weight ratio to obtain the membrane scale inhibitor.

8. Use of the scale inhibitor according to claim 1 in water treatment based on reverse osmosis membrane.

9. The use according to claim 8, characterized in that: The water treatment includes salt water treatment, reclaimed water treatment or sea water treatment.

10. A method for antiscaling a reverse osmosis membrane, comprising adding the membrane antiscalant according to any one of claims 1 to 6 to a reverse osmosis system.

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