Scale inhibition and dispersion agent for treating industrial circulating water and preparation method of scale inhibition and dispersion agent

Abstract

The invention relates to the technical field of water treatment, and discloses a scale inhibition and dispersion agent for treating industrial circulating water and a preparation method thereof.The scale inhibition and dispersion agent is prepared from 2-[(2-aminoethyl) amino] sodium ethanesulfonate, p-hydroxybenzaldehyde, methoxy polyethylene glycol acrylate and beta-cyclodextrin as raw materials. Sodium alkenyl sulfonate long-chain cyclodextrin is obtained through reductive amination, addition and esterification and initiates copolymerization with acrylic acid and itaconic acid to obtain the scale inhibition and dispersion agent of a comb-type structure, and a chelate is dissolved or suspended in a solution through carboxyl, sulfo group and ether group in the structure of the scale inhibition and dispersion agent, so that the effect of effectively dispersing ferric oxide is achieved; polyethylene glycol long chains and beta-cyclodextrin have large steric hindrance and can be stretched, the probability that CaCO3 and BaSO4 crystals collide with each other can be reduced, salt ions and other molecules causing corrosion in a solution are difficult to get close to the metal surface, and the corrosion inhibitor has a good corrosion inhibition effect, is free of phosphorus and environmentally friendly and can be widely applied to an industrial circulating water treatment system.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, in particular to a scale inhibitor and dispersant for treating industrial circulating water and a preparation method thereof. Background Art

[0002] my country is an industrial country that consumes a large amount of water resources for industrial use every year. Impurities such as minerals, microorganisms and organic matter contained in industrial circulating water often lead to equipment scaling, corrosion and other problems, seriously affecting production efficiency and equipment life. In order to overcome these problems, people have developed various water treatment chemicals, among which scale inhibitors and dispersants are an important type. Scale inhibitors and dispersants play a vital role in the treatment of industrial circulating water, especially in the treatment and recycling of water for steelmaking cooling in steel plants and the treatment of some industrial wastewater containing high salt ions. With the acceleration of industrialization and the enhancement of environmental awareness, people have higher and higher performance requirements for scale inhibitors and dispersants. Therefore, the research and development of new, efficient and environmentally friendly scale inhibitors and dispersants has become an important topic in the current field of industrial circulating water treatment.

[0003] Scale inhibitors and dispersants refer to agents that can evenly disperse particles or droplets in another medium during the water treatment process. They prevent mineral deposition, scale formation and particle aggregation in the water treatment system through physical and chemical effects, thereby maintaining the normal working state of the equipment. Scale inhibitors and dispersants on the market are currently divided into two categories: inorganic scale inhibitors and dispersants and organic scale inhibitors. Inorganic scale inhibitors and dispersants mainly include phosphates, silicates, etc., which combine with metal ions in water to form stable complexes, thereby preventing the formation of precipitation. However, inorganic scale inhibitors and dispersants are prone to excessive use during use, leading to environmental problems such as eutrophication of water bodies. Organic scale inhibitors and dispersants are mainly composed of organic acid polymers, polycarboxylates, sulfonates, etc., which chelate or adsorb metal ions such as calcium and magnesium in water through their functional groups. However, the existing organic scale inhibitors and dispersants have unsatisfactory scale inhibition effects under high alkalinity and high pH values, and some polymers have low degradation rates. They are easy to accumulate in the system after long-term use, causing potential pollution to the environment. In addition, some polymers are expensive, which increases production costs, etc., and cannot meet the current requirements for corrosion and scale inhibition of industrial circulating water.

[0004] β-cyclodextrin has a hollow cylindrical stereostructure and a large number of hydroxyl groups, and can form hydrogen bonds with scaling substances such as calcium carbonate, so that a large number of scaling ions cannot further combine with the crystal nucleus and are retained in the water. However, when β-cyclodextrin is added alone as a scale inhibitor and dispersant, it has fewer effective groups and the scale inhibition and dispersion effect is not particularly obvious. The present invention aims to introduce cyclodextrin, carboxyl, sulfonic acid and polyethylene glycol long chain groups into the scale inhibitor and dispersant at the same time, so that the scale inhibitor and dispersant not only has excellent scale inhibition function, but also has excellent dispersing performance. Even in water with high concentration of inorganic salts, it still has efficient corrosion inhibition performance and can be widely used in industrial circulating water treatment systems. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a scale inhibitor and dispersant for treating industrial circulating water and a preparation method thereof, so as to overcome the shortcomings of existing scale inhibitors and dispersants such as environmental pollution and low scale inhibition efficiency, and to provide a green and environmentally friendly scale inhibitor and dispersant with good scale inhibition, dispersion and corrosion inhibition performance.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: A method for preparing a scale inhibitor dispersant for treating industrial circulating water is carried out according to the following steps: Step (1), under nitrogen atmosphere, add maleic anhydride modified β-cyclodextrin to a reaction flask and dissolve it in dichlorothionyl, stir at 70-85°C for 2-5h, remove dichlorothionyl under reduced pressure, add N,N-dimethylformamide, stir to dissolve, add the structural formula The sodium sulfonate-based long-chain phenol is reacted at 60-75°C for 5-12 hours, cooled to room temperature, filtered, washed with methanol, and dried to obtain sodium olefin sulfonate long-chain cyclodextrin.

[0007] Step (2), under a nitrogen atmosphere, add itaconic acid, acrylic acid, sodium olefin sulfonate long-chain cyclodextrin and deionized water to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and add an aqueous solution of ammonium persulfate at a rate of 0.5-0.8 mL / min. After the addition is completed, react at 75-90° C. for 1-3 h, cool to 40-50° C., add an aqueous solution of sodium hydroxide to adjust the pH to neutral, and obtain a scale inhibitor dispersant for treating industrial circulating water.

[0008] Furthermore, in step (1), the ratio of maleic anhydride-modified β-cyclodextrin to sodium sulfonate-based long-chain phenol is 1 mol: (1.2-1.5) mol.

[0009] Furthermore, in step (2), the ratio of itaconic acid, acrylic acid, sodium olefin sulfonate long-chain cyclodextrin, and ammonium persulfate is 100 g: (30-40) g: (2-10) g: (5-8) g.

[0010] Furthermore, the mass fraction of the sodium hydroxide aqueous solution in step (2) is 20-35%.

[0011] Furthermore, the preparation method of sodium sulfonate-based long-chain phenol in step (1) is carried out according to the following steps: Step S1. Under a nitrogen atmosphere, add 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and methanol to a reaction flask, stir to dissolve, add p-hydroxybenzaldehyde, stir at 20-35° C. for 2-5 hours, then add sodium cyanoborohydride, continue to react for 8-16 hours, filter, concentrate under reduced pressure, separate the organic phase by column chromatography (elution with methanol / dichloromethane = 1:20), and dry to obtain sodium diaminosulfonate phenol.

[0012] Step S2, under a nitrogen atmosphere, add sodium diaminosulfonate phenol and chloroform to a reaction flask, stir evenly, add methoxy polyethylene glycol acrylate, stir to react, and after the reaction is completed, concentrate under reduced pressure, wash with deionized water, and separate the organic phase by column chromatography (elution with methanol / chloroform = 1:10) to obtain sodium sulfonate-based long-chain phenol.

[0013] Furthermore, in step S1, the ratio of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt, p-hydroxybenzaldehyde, and sodium cyanoborohydride is 1 mol: (1.02-1.1) mol: (2.2-2.5) mol.

[0014] Furthermore, in step S2, the ratio of sodium diaminosulfonate phenol to methoxy polyethylene glycol acrylate is 1 mol: (2.05-2.2) mol.

[0015] Furthermore, in step S2, the reaction temperature is 50-65° C., and the reaction time is 12-24 h.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The invention uses 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt, p-hydroxybenzaldehyde, methoxy polyethylene glycol acrylate and maleic anhydride modified beta-cyclodextrin as raw materials, obtains sodium olefin sulfonate long-chain type cyclodextrin through reductive amination, addition and esterification reactions, then copolymerizes itaconic acid-acrylic acid-sodium olefin sulfonate long-chain type cyclodextrin under the initiation of ammonium persulfate to obtain a comb-shaped scale inhibitor dispersant for treating industrial circulating water. The invention is phosphorus-free and environmentally friendly, has a simple preparation method, is easy to obtain raw materials and has a low cost, and can be widely used in industrial circulating water treatment systems.

[0017] (1) β-cyclodextrin has a hollow cylindrical structure that is narrow at the top and wide at the bottom, hydrophobic inside and hydrophilic outside. The cavity contains calcium carbonate and barium sulfate microcrystals through van der Waals forces and hydrophobic interaction forces, so that a large number of scale-forming ions cannot further bind to the crystal nucleus and remain in the water. At the same time, a large number of hydroxyl groups in the β-cyclodextrin structure generate negatively charged O - Its molecular chain can chelate with Ca in water 2+ , Ba 2+ The combination of sulfonic acid groups and scale particles is resisted, which resists the combination of scale-forming ions, thereby improving the solubility of calcium and barium ions. The sulfonic acid group is introduced into the polymer as a strong acid group, which has stronger ionic characteristics. The carboxylic acid group as a weak acid group has a stronger binding ability on the scale particles. In addition, the long chain of polyethylene glycol promotes flocculation and bridging between scale particles, which is beneficial to Ca 2+ , Ba 2+ Chelation ensures the long-term effectiveness of chelating scale inhibition and dispersion; the comb-shaped polymer formed by the polymerization of long-chain cyclodextrin sodium olefin sulfonate with acrylic acid and itaconic acid can more effectively form steric hindrance to prevent flocculation and precipitation between particles, making it impossible for the particles to aggregate and difficult to grow into large particles.

[0018] (2) The hydrophilic groups in the scale inhibitor and dispersant, such as carboxyl, sulfonic acid, and ether groups, make the chelate dissolve or suspend in the solution, thereby preventing the precipitation of iron oxide and achieving the effect of dispersing iron oxide; at the same time, the long chain of polyethylene glycol and β-cyclodextrin have a large steric hindrance, which can be stretched to reduce the probability of BaSO4 and CaCO3 crystals colliding with each other, avoiding crystal aggregation, precipitation, and scaling, and more effectively dispersing the particles adsorbed on the walls of pipes or containers.

[0019] (3) The hydroxyl and carboxyl groups in the scale inhibitor and dispersant are dissolved in water and ionized to form negatively charged ions, which interact with the surface charge of the metal, forming a dense hydrophobic film on the metal surface, which plays a role in slowing down corrosion. At the same time, due to the presence of the β-cyclodextrin cavity structure and the larger molecular structure, a stronger steric hindrance is formed, and the hydrophobic film is thick and dense. It is difficult for salt ions and other molecules in the solution that cause corrosion to approach the metal surface, and the corrosion inhibition effect is better. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Unless otherwise specified, the raw materials and reagents used in this application are commercially available or can be prepared by known methods.

[0022] The preparation of maleic anhydride modified β-cyclodextrin refers to "Preparation and Characterization of Maleic Anhydride Acylated β-cyclodextrin Pillared Zn / Al-CO3 Type Hydrotalcite" in Volume 38, Issue 3 of "Applied Chemical Industry": Add 9.9 g of β-cyclodextrin and 100 mL of N,N-dimethylformamide to a reaction flask, stir to dissolve, then add 9.9 g of maleic anhydride and 1.5 g of concentrated sulfuric acid, react at 80°C for 3 hours, add acetone to precipitate, filter, and vacuum dry to obtain maleic anhydride modified β-cyclodextrin.

[0023] Methoxy polyethylene glycol acrylate, CAS number is 32171-39-4, molecular weight is 1010, structural formula is , where n=21.

[0024] 2-[(2-Aminoethyl)amino]ethanesulfonic acid sodium salt, CAS number is 34730-59-1.

[0025] p-Hydroxybenzaldehyde, CAS number is 123-08-0.

[0026] Sodium cyanoborohydride, CAS number is 25895-60-7.

[0027] Itaconic acid, CAS number is 97-65-4.

[0028] Example 1 (1) Under nitrogen atmosphere, add 45 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 180 mL of methanol to a reaction flask. After stirring to dissolve, add 47.7 mmol of p-hydroxybenzaldehyde and stir at 25°C for 4 h. Then add 104.5 mmol of sodium cyanoborohydride and continue the reaction for 12 h. Filter and concentrate under reduced pressure. The organic phase is separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0029] (2) Under nitrogen atmosphere, 40 mmol of sodium diaminosulfonate phenol and 320 mL of chloroform were added to a reaction flask. After stirring evenly, 84 mmol of methoxy polyethylene glycol acrylate was added. The mixture was reacted at 60 °C for 16 h, concentrated under reduced pressure, washed with deionized water, and the organic phase was separated by column chromatography (elution with methanol / chloroform = 1:10) to obtain sodium sulfonate-based long-chain phenol.

[0030] (3) Under nitrogen atmosphere, add 35 mmol of maleic anhydride-modified β-cyclodextrin to the reaction flask and dissolve it in dichlorothionyl. Stir at 75°C for 3 h, remove dichlorothionyl under reduced pressure, add 485 mL of N,N-dimethylformamide, stir to dissolve, add 46.2 mmol of sodium sulfonate-based long-chain phenol, react at 70°C for 10 h, cool to room temperature, filter, wash with methanol, and dry to obtain sodium olefin sulfonate long-chain cyclodextrin. The preparation reaction formula is as follows:

[0031] (4) Under nitrogen atmosphere, 100 g of itaconic acid, 35 g of acrylic acid, 2 g of sodium olefinsulfonate long-chain cyclodextrin and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 6 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.6 mL / min. After the addition was completed, the mixture was reacted at 85 °C for 2 h, cooled to 45 °C, and a 25% by mass sodium hydroxide aqueous solution was added to adjust the pH to neutral, thereby obtaining a scale inhibitor dispersant for treating industrial circulating water.

[0032] Example 2 (1) Under a nitrogen atmosphere, add 120 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 360 mL of methanol to a reaction flask. After stirring to dissolve, add 122.4 mmol of p-hydroxybenzaldehyde and stir at 35°C for 2 h. Then add 264 mmol of sodium cyanoborohydride and continue the reaction for 8 h. Filter and concentrate under reduced pressure. The organic phase is separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0033] (2) Under nitrogen atmosphere, 105 mmol of sodium diaminosulfonate phenol and 630 mL of chloroform were added to a reaction flask. After stirring, 215.25 mmol of methoxy polyethylene glycol acrylate was added. The mixture was reacted at 65 °C for 12 h, concentrated under reduced pressure, washed with deionized water, and the organic phase was separated by column chromatography (elution with methanol / chloroform = 1:10) to obtain sodium sulfonate-based long-chain phenol.

[0034] (3) Under nitrogen atmosphere, add 90 mmol of maleic anhydride-modified β-cyclodextrin dissolved in thionyl chloride into a reaction flask, stir at 85°C for 2 h, remove thionyl chloride under reduced pressure, add 1080 mL of N,N-dimethylformamide, stir to dissolve, add 108 mmol of sodium sulfonate-based long-chain phenol, react at 75°C for 5 h, cool to room temperature, filter, wash with methanol, and dry to obtain sodium olefin sulfonate long-chain cyclodextrin.

[0035] (4) Under nitrogen atmosphere, 100 g of itaconic acid, 30 g of acrylic acid, 4 g of sodium olefinsulfonate long-chain cyclodextrin and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 5 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.8 mL / min. After the addition was completed, the mixture was reacted at 90 °C for 1 h, cooled to 50 °C, and a 35% by mass sodium hydroxide aqueous solution was added to adjust the pH to neutral, thereby obtaining a scale inhibitor dispersant for treating industrial circulating water.

[0036] Example 3 (1) Under nitrogen atmosphere, add 20 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 100 mL of methanol to a reaction flask, stir to dissolve, add 22 mmol of p-hydroxybenzaldehyde, stir at 20°C for 5 h, then add 50 mmol of sodium cyanoborohydride, continue to react for 16 h, filter, and concentrate under reduced pressure. The organic phase is separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0037] (2) Under nitrogen atmosphere, 15 mmol of sodium diaminosulfonate phenol and 150 mL of chloroform were added to the reaction flask. After stirring evenly, 33 mmol of methoxy polyethylene glycol acrylate was added. The mixture was reacted at 50 °C for 24 h, concentrated under reduced pressure, washed with deionized water, and the organic phase was separated by column chromatography (elution with methanol / chloroform = 1:10) to obtain sodium sulfonate-based long-chain phenol.

[0038] (3) Under nitrogen atmosphere, add 10 mmol of maleic anhydride-modified β-cyclodextrin dissolved in thionyl chloride into a reaction flask, stir at 70°C for 5 h, remove thionyl chloride under reduced pressure, add 150 mL of N,N-dimethylformamide, stir to dissolve, add 150 mmol of sodium sulfonate-based long-chain phenol, react at 60°C for 12 h, cool to room temperature, filter, wash with methanol, and dry to obtain sodium olefin sulfonate long-chain cyclodextrin.

[0039] (4) Under nitrogen atmosphere, 100 g of itaconic acid, 40 g of acrylic acid, 6 g of sodium olefinsulfonate long-chain cyclodextrin and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 8 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.5 mL / min. After the addition was completed, the mixture was reacted at 75 °C for 3 h, cooled to 40 °C, and a 20% by mass sodium hydroxide aqueous solution was added to adjust the pH to neutral, thereby obtaining a scale inhibitor dispersant for treating industrial circulating water.

[0040] Example 4 (1) Under nitrogen atmosphere, add 80 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 280 mL of methanol to a reaction flask. After stirring to dissolve, add 84 mmol of p-hydroxybenzaldehyde and stir at 30°C for 5 h. Then add 188.8 mmol of sodium cyanoborohydride and continue the reaction for 15 h. Filter and concentrate under reduced pressure. The organic phase is separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0041] (2) Under nitrogen atmosphere, 65 mmol of sodium diaminosulfonate phenol and 520 mL of chloroform were added to a reaction flask. After stirring evenly, 137.8 mmol of methoxy polyethylene glycol acrylate was added and the mixture was reacted at 55 °C for 18 h. The mixture was concentrated under reduced pressure and washed with deionized water. The organic phase was separated by column chromatography (elution with methanol / chloroform = 1:10) to obtain sodium sulfonate-based long-chain phenol.

[0042] (3) Under nitrogen atmosphere, add 50 mmol of maleic anhydride-modified β-cyclodextrin dissolved in thionyl chloride into a reaction flask, stir at 80°C for 3 h, remove thionyl chloride under reduced pressure, add 625 mL of N,N-dimethylformamide, stir to dissolve, add 67 mmol of sodium sulfonate-based long-chain phenol, react at 70°C for 10 h, cool to room temperature, filter, wash with methanol, and dry to obtain sodium olefin sulfonate long-chain cyclodextrin.

[0043] (4) Under nitrogen atmosphere, 100 g of itaconic acid, 32 g of acrylic acid, 8 g of sodium olefinsulfonate long-chain cyclodextrin and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 7 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.75 mL / min. After the addition was completed, the mixture was reacted at 85 °C for 2 h, cooled to 45 °C, and a 30% by mass sodium hydroxide aqueous solution was added to adjust the pH to neutral, thereby obtaining a scale inhibitor dispersant for treating industrial circulating water.

[0044] Example 5 (1) Under nitrogen atmosphere, add 40 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 145 mL of methanol to a reaction flask. After stirring to dissolve, add 43.2 mmol of p-hydroxybenzaldehyde and stir at 30°C for 4 h. Then add 96 mmol of sodium cyanoborohydride and continue the reaction for 12 h. Filter and concentrate under reduced pressure. The organic phase is separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0045] (2) Under nitrogen atmosphere, 32 mmol of sodium diaminosulfonate phenol and 275 mL of chloroform were added to the reaction flask. After stirring evenly, 67.2 mmol of methoxy polyethylene glycol acrylate was added and the mixture was reacted at 60 °C for 24 h. The mixture was concentrated under reduced pressure and washed with deionized water. The organic phase was separated by column chromatography (elution with methanol / chloroform = 1:10) to obtain sodium sulfonate-based long-chain phenol.

[0046] (3) Under nitrogen atmosphere, add 25 mmol of maleic anhydride-modified β-cyclodextrin dissolved in dichlorothionyl into a reaction flask, stir at 80°C for 5 h, remove the dichlorothionyl under reduced pressure, add 375 mL of N,N-dimethylformamide, stir to dissolve, add 35 mmol of sodium sulfonate-based long-chain phenol, react at 70°C for 12 h, cool to room temperature, filter, wash with methanol, and dry to obtain sodium olefin sulfonate long-chain cyclodextrin.

[0047] (4) Under nitrogen atmosphere, 100 g of itaconic acid, 30 g of acrylic acid, 10 g of sodium olefinsulfonate long-chain cyclodextrin and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 8 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.8 mL / min. After the addition was completed, the mixture was reacted at 85 °C for 3 h, cooled to 50 °C, and a 30% by mass sodium hydroxide aqueous solution was added to adjust the pH to neutral, thereby obtaining a scale inhibitor dispersant for treating industrial circulating water.

[0048] Comparative Example 1 (1) Under nitrogen atmosphere, 35 mmol of maleic anhydride-modified β-cyclodextrin was added to a reaction flask and dissolved in thionyl chloride. The mixture was stirred at 75° C. for 3 h. The thionyl chloride was removed under reduced pressure. 485 mL of N,N-dimethylformamide was added and stirred to dissolve. 46.2 mmol of sodium diaminosulfonate phenol (prepared in Example 1) was added and reacted at 70° C. for 10 h. The mixture was cooled to room temperature, filtered, washed with methanol, and dried to obtain sodium olefinsulfonate cyclodextrin.

[0049] (2) Under a nitrogen atmosphere, 100 g of itaconic acid, 35 g of acrylic acid, 2 g of sodium olefinsulfonate cyclodextrin and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 6 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.6 mL / min. After the addition was completed, the mixture was reacted at 85 °C for 2 h, cooled to 45 °C, and a 25% by mass sodium hydroxide aqueous solution was added to adjust the pH to neutral, thereby obtaining a scale inhibitor dispersant for treating industrial circulating water.

[0050] Comparative Example 2 Under a nitrogen atmosphere, 100 g of itaconic acid, 35 g of acrylic acid, 2 g of maleic anhydride-modified β-cyclodextrin and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 6 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.6 mL / min. After the addition was completed, the reaction was carried out at 85 ° C for 2 h, the temperature was lowered to 45 ° C, and a 25% mass fraction of sodium hydroxide aqueous solution was added to adjust the pH to neutral to obtain a scale inhibitor dispersant for treating industrial circulating water.

[0051] Comparative Example 3 Under a nitrogen atmosphere, 100 g of itaconic acid, 35 g of acrylic acid and deionized water were added to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and 6 g of an aqueous solution of ammonium persulfate was added dropwise at a rate of 0.6 mL / min. After the addition was completed, the reaction was carried out at 85 ° C for 2 h, the temperature was lowered to 45 ° C, and a 25% mass fraction of sodium hydroxide aqueous solution was added to adjust the pH to neutral to obtain a scale inhibitor dispersant for treating industrial circulating water.

[0052] Test on the scale inhibition performance of calcium carbonate: refer to GB / T 16632-2008 standard, take distilled water to prepare Ca 2+ and HCO3 - Test water (8 portions) with mass concentrations of 600 and 1200 mg / L (both in terms of CaCO3) was taken out, 500 mL of each portion was placed in a conical flask, and 50 mg of scale inhibitors and dispersants prepared in the examples and comparative examples were added, respectively. The mixture was heated in a constant temperature water bath at 80°C for 10 h, cooled to room temperature, and the supernatant was taken out and titrated with EDTA to determine the remaining Ca 2+ The concentration of scale inhibitor was taken and a blank experiment was performed at the same time. The scale inhibition rate η1 = (V1-V0) / (V2-V0) × 100%, where V0, V1, and V2 are the volumes (mL) of EDTA consumed by the total calcium content in the raw water after heating without adding scale inhibitor dispersant, after heating with scale inhibitor dispersant, and at room temperature, respectively.

[0053] Test of barium sulfate scale inhibition performance: According to the SY / T 5673-93 "Performance Evaluation Method of Oilfield Scale Inhibitors", distilled water was used to prepare Ba 2+ and SO4 2- The test water with mass concentration of 5000 and 7500 mg / L (both in BaSO4) (8 portions in total) was taken, 500 mL of each portion was put into a conical flask, and 50 mg of scale inhibitors prepared in the examples and comparative examples were added respectively. The water was placed in a constant temperature water bath at 70°C for 24 hours, and then cooled to room temperature. After the test, the supernatant was taken and titrated with EDTA to determine the remaining BaSO4. 2+ The concentration of the blank water sample was taken at the same time, and the scale inhibition rate η2 = (ρ1-ρ0) / (ρ2-ρ0) × 100%, where ρ0, ρ1, ρ2 are the Ba in the raw water after heating without adding scale inhibitor dispersant, after heating with scale inhibitor dispersant and at room temperature respectively.2+ The mass concentration of (mg / L).

[0054] Table 1 Scale inhibition performance test

[0055] From the test results in the table above, it can be seen that with the increase of the content of sodium olefin sulfonate long-chain cyclodextrin, the scale inhibitor can be combined with Ca 2+ , Ba 2+ The content of chelated groups increases, and the scale inhibition performance is significantly improved. In Example 5, the scale inhibition rate for calcium carbonate reaches 100%, and the scale inhibition rate for barium sulfate is 98.6%. This is because, on the one hand, β-cyclodextrin has a hollow cylindrical three-dimensional structure of "narrow on the top and wide on the bottom, hydrophobic inside and hydrophilic outside", and the inside of the cavity contains calcium carbonate and barium sulfate microcrystals through van der Waals force, hydrophobic interaction force, etc., so that a large number of scale-forming ions cannot further combine with the crystal nucleus and are retained in the water; at the same time, a large number of hydroxyl groups in the β-cyclodextrin structure generate negatively charged O - Its molecular chain can chelate with Ca in water 2+ , Ba 2+ The combination of sulfonic acid groups and scale particles is inhibited, thereby increasing the solubility of calcium and barium ions. On the other hand, the sulfonic acid group is introduced into the polymer as a strong acid group, which has stronger ionic characteristics. The carboxylic acid group as a weak acid group has a stronger binding ability on the scale particles. In addition, the long chain of polyethylene glycol promotes flocculation and bridging between scale particles, which is beneficial to Ca 2+ , Ba 2+ Chelation ensures the long-term effectiveness of chelating scale inhibition and dispersion; the comb-shaped polymer formed by the polymerization of sodium olefin sulfonate long-chain cyclodextrin with acrylic acid and itaconic acid can more effectively form steric hindrance to prevent flocculation and precipitation between particles, making it difficult for particles to aggregate and grow into large-volume particles. Comparative Example 1 does not contain polyethylene glycol long chains and cannot form a comb-shaped polymer structure; Comparative Example 2 does not contain polyethylene glycol long chains and sulfonic acid groups, and the chelating effect is limited; Comparative Example 3 does not contain cyclodextrin, sulfonic acid groups and polyethylene glycol long chains, and the scale inhibition group is single, and the scale inhibition effect is limited.

[0056] Dispersion performance test: 8 groups of Ca 2+ The mass concentration is 150 mg / L (calculated as CaCO3), Fe 2+ To the experimental water with a concentration of 10 mg / L and a pH of 9 (adjusted with borax), 50 mg of the scale inhibitor and dispersant prepared in the embodiment and the comparative example were added respectively, and the mixture was placed in a 50°C water bath for 5 hours. The upper clear liquid was taken and the transmittance T at 450 nm and a 3 cm colorimetric cell was measured with a visible light spectrophotometer. The transmittance of distilled water was 100% as a reference. The smaller the transmittance, the better the dispersion effect.

[0057] Table 2 Dispersion performance test

[0058] Ferrous ions can be oxidized into ferric oxide in alkaline solution. If the dispersibility of the polymer is poor, the ferric oxide will precipitate and the transmittance of the solution will be large. On the contrary, the smaller the transmittance, the better the dispersibility of the polymer. It can be seen from the test results in the above table that with the increase of the content of sodium olefin sulfonate long-chain cyclodextrin, the dispersibility of the scale inhibitor dispersant on ferric oxide is enhanced. This is because the hydrophilic groups in the scale inhibitor dispersant, such as carboxyl, sulfonic acid, and ether groups, make the chelate dissolve or suspend in the solution, thereby preventing the precipitation of ferric oxide and achieving the effect of dispersing ferric oxide. At the same time, the long chain of polyethylene glycol and β-cyclodextrin have a large steric hindrance, which can be stretched to reduce the probability of BaSO4 and CaCO3 crystals colliding with each other, avoid crystal aggregation, precipitation, and scaling, and more effectively disperse the particles adsorbed on the walls of pipes or containers.

[0059] Corrosion inhibition performance test: Referring to GB / T 18175-2014 "Determination of corrosion inhibition performance of water treatment agents - Rotating hanging plate method", the corrosion inhibition performance of the scale inhibitors and dispersants prepared in the examples and comparative examples was measured. A3 carbon steel was used for the test hanging plates, and the corrosion inhibition rate was calculated based on the difference in corrosion rate before and after treatment of A3 carbon steel. The larger the corrosion inhibition rate, the better the corrosion resistance.

[0060] Table 3 Corrosion inhibition performance test

[0061] The higher the corrosion inhibition rate, the stronger the inhibitory effect on metal corrosion and the better the corrosion resistance. The hydroxyl and carboxyl groups in the scale inhibitor and dispersant are dissolved in water and ionized to form negatively charged ions, which interact with the surface charge of the metal, forming a dense hydrophobic film on the metal surface, which plays a role in slowing down corrosion. At the same time, the presence of the β-cyclodextrin cavity structure and the larger molecular structure form a stronger steric hindrance, making the hydrophobic film thick and dense, making it difficult for salt ions and other molecules in the solution that cause corrosion to approach the metal surface, and the corrosion inhibition effect is better.

[0062] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a scale inhibitor dispersant for treating industrial circulating water, characterized in that: The preparation method is carried out according to the following steps: Step (1), under a nitrogen atmosphere, add maleic anhydride modified β-cyclodextrin to a reaction flask and dissolve it in dichlorothionyl, stir at 70-85° C. for 2-5 hours, remove dichlorothionyl under reduced pressure, add N,N-dimethylformamide, stir to dissolve, add sodium sulfonate long-chain phenol, react at 60-75° C. for 5-12 hours, cool to room temperature, filter, wash with methanol, and dry to obtain sodium olefin sulfonate long-chain cyclodextrin; Step (2), under a nitrogen atmosphere, add itaconic acid, acrylic acid, sodium olefin sulfonate long-chain cyclodextrin and deionized water to a reaction flask equipped with a dropping funnel, a thermometer and a condenser, and add an aqueous solution of ammonium persulfate at a rate of 0.5-0.8 mL / min. After the addition is completed, react at 75-90° C. for 1-3 h, cool to 40-50° C., add an aqueous solution of sodium hydroxide to adjust the pH to neutral, and obtain a scale inhibitor dispersant for treating industrial circulating water.

2. The method for preparing a scale inhibitor and dispersant for treating industrial circulating water according to claim 1, characterized in that: In the step (1), the ratio of maleic anhydride-modified β-cyclodextrin to sodium sulfonate-based long-chain phenol is 1 mol: (1.2-1.5) mol.

3. The method for preparing a scale inhibitor and dispersant for treating industrial circulating water according to claim 1, characterized in that: In the step (2), the ratio of itaconic acid, acrylic acid, sodium olefin sulfonate long-chain cyclodextrin, and ammonium persulfate is 100 g: (30-40) g: (2-10) g: (5-8) g.

4. The method for preparing a scale inhibitor and dispersant for treating industrial circulating water according to claim 1, characterized in that: The mass fraction of the sodium hydroxide aqueous solution in step (2) is 20-35%.

5. The method for preparing a scale inhibitor and dispersant for treating industrial circulating water according to claim 1, characterized in that: The preparation method of sodium sulfonate-based long-chain phenol in step (1) is carried out according to the following steps: Step S1, under a nitrogen atmosphere, add 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and methanol to a reaction flask, stir to dissolve, add p-hydroxybenzaldehyde, stir at 20-35° C. for 2-5 h, then add sodium cyanoborohydride, continue to react for 8-16 h, filter, concentrate under reduced pressure, separate the organic phase by column chromatography, and dry to obtain sodium diaminosulfonate phenol; Step S2, under a nitrogen atmosphere, add sodium diaminosulfonate phenol and chloroform to a reaction flask, stir evenly, add methoxy polyethylene glycol acrylate, stir to react, and after the reaction is completed, concentrate under reduced pressure, wash with deionized water, and separate the organic phase by column chromatography to obtain sodium sulfonate-based long-chain phenol.

6. The method for preparing a scale inhibitor and dispersant for treating industrial circulating water according to claim 5, characterized in that: In the step S1, the ratio of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt, p-hydroxybenzaldehyde, and sodium cyanoborohydride is 1 mol: (1.02-1.1) mol: (2.2-2.5) mol.

7. The method for preparing a scale inhibitor and dispersant for treating industrial circulating water according to claim 5, characterized in that: In the step S2, the ratio of sodium diaminosulfonate phenol to methoxy polyethylene glycol acrylate is 1 mol: (2.05-2.2) mol.

8. The method for preparing a scale inhibitor and dispersant for treating industrial circulating water according to claim 5, characterized in that: In step S2, the reaction temperature is 50-65° C. and the reaction time is 12-24 h.

9. A scale inhibitor and dispersant for treating industrial circulating water, characterized in that: Obtained by the preparation method according to any one of claims 1 to 8.

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