A scale inhibitor and dispersant for treating industrial circulating water and its preparation method

Abstract

The invention relates to the technical field of water treatment and discloses a scale inhibitor and dispersant for treating industrial circulating water and a preparation method thereof. 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt, p-hydroxybenzaldehyde, methoxy polyethylene glycol acrylate and beta-cyclodextrin are used as raw materials, and sodium olefin sulfonate long-chain type cyclodextrin is obtained through reductive amination, addition and esterification. The long-chain cyclodextrin is then copolymerized with acrylic acid and itaconic acid to obtain a scale inhibitor and dispersant with a comb-shaped structure. The carboxyl groups, sulfonic acid groups and ether groups in the structure enable the chelate to be dissolved or suspended in a solution, thereby effectively dispersing iron oxide. The long polyethylene glycol chain and the beta-cyclodextrin have large steric hindrance and can be stretched to reduce the probability of collision between CaCO3 and BaSO4 crystals, making it difficult for salt ions and other corrosion-causing molecules in the solution to approach the metal surface. The scale inhibitor and dispersant have good corrosion inhibition effect, are phosphorus-free and environmentally friendly, and can be widely used in industrial circulating water treatment systems.

Description

Technical Field

[0001] The present 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 a major industrial country that consumes a large amount of water resources for industrial use every year. Due to the impurities such as minerals, microorganisms and organic matter contained in industrial circulating water, it often causes 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 mills, as well as the treatment of some industrial wastewater containing high salt ions. With the acceleration of industrialization and the enhancement of environmental awareness, people's performance requirements for scale inhibitors and dispersants are also getting higher and higher. 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 are agents that can evenly disperse particles or droplets in another medium during the water treatment process. Through physical and chemical reactions, they prevent mineral deposition, scale formation, and particle aggregation in water treatment systems, thereby maintaining the normal operation of equipment. Currently, scale inhibitors and dispersants on the market are divided into two categories: inorganic and organic. Inorganic scale inhibitors and dispersants primarily include phosphates and silicates, which bind to metal ions in water to form stable complexes, thereby preventing precipitation. However, excessive use of inorganic scale inhibitors can lead to environmental problems such as eutrophication. Organic scale inhibitors and dispersants primarily consist of organic acid polymers, polycarboxylates, and sulfonates. Their functional groups chelate or adsorb metal ions such as calcium and magnesium in water. However, existing organic scale inhibitors and dispersants are less effective at high alkalinity and high pH values. Some polymers have low degradation rates, making them prone to accumulation in the system after long-term use, potentially polluting the environment. Furthermore, some polymers are expensive, increasing production costs, making them unable to meet the current requirements for corrosion and scale inhibition in industrial circulating water.

[0004] β-cyclodextrin has a hollow cylindrical three-dimensional structure and a large number of hydroxyl groups, which can form hydrogen bonds with scaling substances such as calcium carbonate, so that a large number of scale-forming 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 simultaneously introduce cyclodextrin, carboxyl, sulfonic acid and polyethylene glycol long chain groups into the scale inhibitor and dispersant, 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:

[0007] A method for preparing a scale inhibitor and dispersant for treating industrial circulating water is carried out according to the following steps:

[0008] Step (1), under nitrogen atmosphere, add maleic anhydride modified β-cyclodextrin to the 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 and 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.

[0009] Step (2): under a nitrogen atmosphere, add itaconic acid, acrylic acid, sodium olefinsulfonate 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 dropwise at a rate of 0.5-0.8 mL / min. After the addition is completed, react at 75-90° C. for 1-3 hours, cool to 40-50° C., add an aqueous solution of sodium hydroxide to adjust the pH to neutral, and obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0010] 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.

[0011] 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.

[0012] Furthermore, the mass fraction of the sodium hydroxide aqueous solution in step (2) is 20-35%.

[0013] Furthermore, the preparation method of sodium sulfonate-based long-chain phenol in step (1) is carried out according to the following steps:

[0014] 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 the reaction for 8-16 hours, filter, and concentrate under reduced pressure. The organic phase is separated by column chromatography (elution with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0015] Step S2: Under a nitrogen atmosphere, sodium diaminosulfonate phenol and chloroform were added to a reaction flask, stirred evenly, and then methoxy polyethylene glycol acrylate was added and stirred for reaction. After the reaction was completed, 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.

[0016] 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.

[0017] Furthermore, in step S2, the ratio of sodium diaminosulfonate phenol to methoxy polyethylene glycol acrylate is 1 mol: (2.05-2.2) mol.

[0018] Furthermore, in step S2, the reaction temperature is 50-65° C., and the reaction time is 12-24 h.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 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, and obtains sodium olefin sulfonate long-chain cyclodextrin through reductive amination, addition and esterification reactions. Then, itaconic acid-acrylic acid-sodium olefin sulfonate long-chain cyclodextrin is copolymerized under the initiation of ammonium persulfate to obtain a comb-shaped scale inhibitor and dispersant for treating industrial circulating water. The invention is phosphorus-free and environmentally friendly, has a simple preparation method, and the raw materials are readily available and low in cost. The invention can be widely used in industrial circulating water treatment systems.

[0021] (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 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 can resist the combination of scale 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 will promote the flocculation and bridging effect between the scale particles, which is beneficial to Ca 2+ 、Ba 2+ Chelation ensures the long-term effectiveness of chelation 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 not easily grow into large particles.

[0022] (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.

[0023] (3) The hydroxyl and carboxyl groups in the scale inhibitor dispersant dissolve in water and ionize to form negatively charged ions that interact with the surface charge of the metal, covering the metal surface with a dense hydrophobic film, 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 spatial steric hindrance, the hydrophobic film is thick and dense, and the salt ions and other molecules in the solution that cause corrosion are difficult to approach the metal surface, resulting in a better corrosion inhibition effect. DETAILED DESCRIPTION

[0024] 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 embodiments described 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Unless otherwise stated, the raw materials and reagents used in this application are commercially available or can be prepared by known methods.

[0026] The preparation of maleic anhydride modified β-cyclodextrin was carried out with reference 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": 9.9 g of β-cyclodextrin and 100 mL of N,N-dimethylformamide were added to a reaction flask, stirred to dissolve, and then 9.9 g of maleic anhydride and 1.5 g of concentrated sulfuric acid were added. The mixture was reacted at 80°C for 3 h, acetone was added for precipitation, filtered, and vacuum dried to obtain maleic anhydride modified β-cyclodextrin.

[0027] Methoxy polyethylene glycol acrylate, CAS number 32171-39-4, molecular weight 1010, structural formula , where n=21.

[0028] 2-[(2-Aminoethyl)amino]ethanesulfonic acid sodium salt, CAS number is 34730-59-1.

[0029] p-Hydroxybenzaldehyde, CAS number is 123-08-0.

[0030] Sodium cyanoborohydride, CAS number 25895-60-7.

[0031] Itaconic acid, CAS number is 97-65-4.

[0032] Example 1

[0033] (1) Under nitrogen atmosphere, 45 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 180 mL of methanol were added to a reaction flask. After stirring to dissolve, 47.7 mmol of p-hydroxybenzaldehyde was added and stirred at 25°C for 4 h. Then, 104.5 mmol of sodium cyanoborohydride was added and the reaction was continued for 12 h. The mixture was filtered and concentrated under reduced pressure. The organic phase was separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0034] (2) Under nitrogen atmosphere, 40 mmol of sodium diaminosulfonate phenol and 320 mL of chloroform were added to the 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.

[0035] (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 and stir to dissolve. Add 46.2 mmol of sodium sulfonate-based long-chain phenol and 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:

[0036]

[0037] (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 ammonium persulfate aqueous solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0038] Example 2

[0039] (1) Under nitrogen atmosphere, 120 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 360 mL of methanol were added to a reaction flask. After stirring and dissolving, 122.4 mmol of p-hydroxybenzaldehyde was added and stirred at 35°C for 2 h. Then, 264 mmol of sodium cyanoborohydride was added and the reaction was continued for 8 h. The mixture was filtered and concentrated under reduced pressure. The organic phase was separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0040] (2) Under nitrogen atmosphere, 105 mmol of sodium diaminosulfonate phenol and 630 mL of chloroform were added to the reaction flask. After stirring evenly, 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.

[0041] (3) Under nitrogen atmosphere, add 90 mmol of maleic anhydride-modified β-cyclodextrin to the reaction flask and dissolve it in dichlorothionyl. Stir at 85 °C for 2 h. Remove dichlorothionyl under reduced pressure. Add 1080 mL of N,N-dimethylformamide and stir to dissolve. Add 108 mmol of sodium sulfonate-based long-chain phenol and 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.

[0042] (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 ammonium persulfate aqueous solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0043] Example 3

[0044] (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. After stirring to dissolve, add 22 mmol of p-hydroxybenzaldehyde and stir at 20°C for 5 h. Then add 50 mmol of sodium cyanoborohydride and continue the reaction 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.

[0045] (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.

[0046] (3) Under nitrogen atmosphere, add 10 mmol of maleic anhydride-modified β-cyclodextrin to the reaction flask and dissolve it in dichlorothionyl. Stir at 70 °C for 5 h. Remove dichlorothionyl under reduced pressure. Add 150 mL of N,N-dimethylformamide and stir to dissolve. Add 150 mmol of sodium sulfonate-based long-chain phenol and 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.

[0047] (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 ammonium persulfate aqueous solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0048] Example 4

[0049] (1) Under nitrogen atmosphere, 80 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 280 mL of methanol were added to a reaction flask. After stirring and dissolving, 84 mmol of p-hydroxybenzaldehyde was added and stirred at 30°C for 5 h. Then, 188.8 mmol of sodium cyanoborohydride was added and the reaction was continued for 15 h. The mixture was filtered and concentrated under reduced pressure. The organic phase was separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0050] (2) Under nitrogen atmosphere, 65 mmol of sodium diaminosulfonate phenol and 520 mL of chloroform were added to the 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.

[0051] (3) Under nitrogen atmosphere, 50 mmol of maleic anhydride-modified β-cyclodextrin was added to the reaction flask and dissolved in dichlorothionyl. The mixture was stirred at 80 °C for 3 h. The dichlorothionyl was removed under reduced pressure. 625 mL of N,N-dimethylformamide was added and stirred to dissolve. 67 mmol of sodium sulfonate-based long-chain phenol 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 olefin sulfonate long-chain cyclodextrin.

[0052] (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 ammonium persulfate aqueous solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0053] Example 5

[0054] (1) Under nitrogen atmosphere, 40 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and 145 mL of methanol were added to a reaction flask. After stirring and dissolving, 43.2 mmol of p-hydroxybenzaldehyde was added and stirred at 30°C for 4 h. Then, 96 mmol of sodium cyanoborohydride was added and the reaction was continued for 12 h. The mixture was filtered and concentrated under reduced pressure. The organic phase was separated by column chromatography (eluted with methanol / dichloromethane = 1:20) and dried to obtain sodium diaminosulfonate phenol.

[0055] (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.

[0056] (3) Under nitrogen atmosphere, add 25 mmol of maleic anhydride-modified β-cyclodextrin to the reaction flask and dissolve it in dichlorothionyl. Stir at 80 °C for 5 h. Remove dichlorothionyl under reduced pressure. Add 375 mL of N,N-dimethylformamide and stir to dissolve. Add 35 mmol of sodium sulfonate-based long-chain phenol and 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.

[0057] (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 ammonium persulfate aqueous solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0058] Comparative Example 1

[0059] (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.

[0060] (2) Under 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 ammonium persulfate aqueous solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0061] Comparative Example 2

[0062] 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 ammonium persulfate solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0063] Comparative Example 3

[0064] 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 ammonium persulfate solution 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 to obtain a scale inhibitor and dispersant for treating industrial circulating water.

[0065] 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 as CaCO3) was taken, 500 mL of each portion was placed in a conical flask, 50 mg of scale inhibitors and dispersants prepared in the examples and comparative examples were added, and heated in a constant temperature water bath at 80°C for 10 h. The mixture was taken out and cooled to room temperature. The supernatant was titrated with EDTA to determine the residual CaCO3. 2+ The concentration of scale inhibitor was determined, 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 and dispersant, after heating with scale inhibitor and dispersant, and at room temperature, respectively.

[0066] Test of barium sulfate scale inhibition performance: According to SY / T 5673-93 "Performance Evaluation Method of Oilfield Antiscalant", distilled water was used to prepare Ba 2+ and SO4 2- The test water with mass concentration of 5000 and 7500 mg / L (both calculated as BaSO4) was taken (a total of 8 parts). 500 mL of each part was placed in a triangular flask, and 50 mg of scale inhibitors and dispersants 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 the remaining BaSO4 was titrated with EDTA. 2+The concentration of the blank water sample was prepared at the same time, and the scale inhibition rate η2 = (ρ1-ρ0) / (ρ2-ρ0) × 100%, where ρ0, ρ1, and ρ2 were respectively the Ba in the raw water without adding the scale inhibitor and dispersant, after adding the scale inhibitor and dispersant, and at room temperature. 2+ The mass concentration of (mg / L).

[0067] Table 1 Scale inhibition performance test

[0068]

[0069] From the test results in the table above, we can see 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 at the top and wide at the bottom, hydrophobic inside and hydrophilic outside", and the interior of the cavity contains calcium carbonate and barium sulfate microcrystals through van der Waals force and hydrophobic interaction force, 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 can resist the combination of scale ions, thereby improving 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 will promote the flocculation and bridging effect between the scale particles, which is beneficial to Ca 2+ 、Ba 2+ Chelation ensures the long-term effectiveness of chelated 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 effectively creates steric hindrance to prevent flocculation and precipitation between particles, preventing particle aggregation and growth into large particles. Comparative Example 1 does not contain long polyethylene glycol chains and therefore cannot form a comb-shaped polymer structure. Comparative Example 2 lacks long polyethylene glycol chains and sulfonic acid groups, resulting in limited chelation. Comparative Example 3 lacks cyclodextrin, sulfonic acid groups, and long polyethylene glycol chains, resulting in a single scale inhibition group and limited scale inhibition.

[0070] Dispersion performance test: Configure 8 groups of Ca 2+ The mass concentration is 150 mg / L (calculated as CaCO3), Fe 2+To 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 examples and comparative examples were added respectively, and the mixture was placed in a 50°C water bath and allowed to stand for 5 hours. The supernatant was taken and the transmittance T at 450 nm and a 3 cm colorimetric cell was measured using a visible light spectrophotometer. The transmittance of distilled water was 100% as a reference. The lower the transmittance, the better the dispersion effect.

[0071] Table 2 Dispersion performance test

[0072]

[0073] Ferrous ions can be oxidized into ferric oxide in alkaline solutions. If the polymer has poor dispersibility, the ferric oxide will precipitate, and the solution's transmittance will be high. Conversely, the lower the transmittance, the better the polymer's dispersibility. The test results in the table above show that as the content of long-chain cyclodextrin sodium olefin sulfonate increases, the scale inhibitor's dispersibility of ferric oxide increases. This is because the hydrophilic groups in the scale inhibitor, such as carboxyl, sulfonic acid, and ether groups, allow the chelate to dissolve or suspend in the solution, thereby preventing the precipitation of ferric oxide and achieving the desired dispersion effect. At the same time, the long-chain polyethylene glycol and β-cyclodextrin have significant steric hindrance, allowing them to expand and reduce the probability of BaSO4 and CaCO3 crystals colliding with each other, preventing crystal aggregation and precipitation, and more effectively dispersing particulate matter adsorbed on the walls of pipes or containers.

[0074] Corrosion inhibition performance test: With reference to GB / T 18175-2014 "Determination of corrosion inhibition performance of water treatment agents - Rotating coupon 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 as the test coupon. The corrosion inhibition rate was calculated based on the difference in corrosion rate before and after treatment of the A3 carbon steel. The greater the corrosion inhibition rate, the better the corrosion resistance.

[0075] Table 3 Corrosion inhibition performance test

[0076]

[0077] 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 dissolve in water and ionize 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 strong steric hindrance, the hydrophobic film is thick and dense, and it is difficult for salt ions and other corrosion-causing molecules in the solution to approach the metal surface, resulting in a better corrosion inhibition effect.

[0078] The above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a scale inhibitor and 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, maleic anhydride-modified β-cyclodextrin is added to a reaction flask and dissolved in thionyl chloride, stirred at 70-85° C. for 2-5 hours, thionyl chloride is removed under reduced pressure, N,N-dimethylformamide is added, stirred and dissolved, sodium sulfonate-based long-chain phenol is added, 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; the structural formula of the sodium olefin sulfonate long-chain cyclodextrin is: ； Step (2): under a nitrogen atmosphere, add itaconic acid, acrylic acid, sodium olefinsulfonate 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 dropwise at a rate of 0.5-0.8 mL / min. After the addition is completed, react at 75-90° C. for 1-3 hours, cool to 40-50° C., add an aqueous solution of sodium hydroxide to adjust the pH to neutral, and obtain a scale inhibitor and 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 hours, then add sodium cyanoborohydride, continue the reaction for 8-16 hours, filter, and concentrate under reduced pressure. The organic phase is separated by column chromatography and dried to obtain sodium diaminosulfonate phenol; Step S2: Under a nitrogen atmosphere, sodium diaminosulfonate phenol and chloroform were added to a reaction flask, stirred evenly, and then methoxy polyethylene glycol acrylate was added and stirred for reaction. After the reaction was completed, the mixture was concentrated under reduced pressure, washed with deionized water, and the organic phase was separated 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 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 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: The method is obtained by the preparation method according to any one of claims 1 to 8.

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