Anti-scale agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a scale inhibitor and a preparation method and application thereof. The preparation method comprises the following steps: adding iminodi (methyl phosphoric acid), 1, 4-dichloro-2-butene and ethanol into a four-neck flask, heating and carrying out a heat preservation reaction, cooling to below 50 DEG C, adding 2-aminobenzene-1, 3, 5-tricarboxylic acid, heating and carrying out a reflux reaction, and carrying out reduced pressure distillation to obtain a viscous solid; adding distilled water, stirring and dissolving, adding (2-acrylamido ethyl) phosphonic acid and buffer salt, and uniformly stirring; dropwise adding an initiator, carrying out stirring reaction after dropwise adding, continuously carrying out heat preservation reaction to obtain a viscous mixed solution, and cooling the viscous mixed solution to 40 DEG C or below; and drying and granulating to obtain the product scale inhibitor. The scale inhibitor has the advantages of being wide in raw material source, simple in synthesis process, free of pollution and good in scale inhibition effect.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and specifically relates to an antiscaling agent and a preparation method and application thereof. Background Art

[0002] With the rapid development of industry, the amount of industrial water is increasing, and the recycling of water is becoming more and more important. After repeated use, circulating cooling water is prone to produce inorganic calcium scale, such as calcium carbonate, calcium sulfate, barium sulfate, etc. These calcium scales adhere to the inner surface of the pipeline, which will greatly reduce the cooling efficiency of the circulating cooling water, and will also cause concentration cell corrosion and local temperature corrosion, which will bring great disadvantages to industrial production. Therefore, it is urgent to improve the recycling rate of industrial cooling water.

[0003] Adding scale inhibitors to circulating water is an effective method. Scale inhibitors have the functions of chelating, dispersing and lattice distortion on scales, and can effectively inhibit the formation of scales. Scale inhibitors have been widely used in many occasions such as industrial circulating cooling water, seawater desalination, boilers, geothermal resource development, and oil and gas field development to slow down and prevent the precipitation and scaling of insoluble substances on the metal surface, and maintain the service life and heat transfer effect of metal equipment.

[0004] Tie Chengjun et al. synthesized the MA / AM / HPA copolymer scale inhibitor in "Performance of Copolymer Scale Inhibitor MA / AM / HPA" and conducted comprehensive tests in oilfield water environment. They investigated the inhibition efficiency of the polymer on calcium carbonate, calcium sulfate, barium sulfate and strontium sulfate under different pH, temperature, sodium chloride content and other factors. In indoor tests in oilfield water, the scale inhibition rate of 25 mg / L polymer after constant temperature at 60°C for 24 hours can reach more than 90%.

[0005] Chinese patent CN102838215A discloses a composite scale inhibitor composed of polyepoxysuccinic acid, ethylenediaminetetramethylenephosphonic acid, itaconic acid-maleic acid-acrylic acid-methyl acrylate polymer and dendritic polyamide-amine. The weight percentage of each component of the scale inhibitor is: polyepoxysuccinic acid 22-32%, ethylenediaminetetramethylenephosphonic acid 10-18%, itaconic acid-maleic acid-acrylic acid-methyl acrylate polymer 35-50%, dendritic polyamide-amine 10-18%, and the rest is water.

[0006] There are some common problems when using these products, either the dosage is too large or the effect is poor. Therefore, it is very necessary to develop high-efficiency and low-dosage scale inhibitors for water treatment. Summary of the invention

[0007] The present invention aims at the deficiencies of the current prior art and provides an anti-scaling agent and a preparation method and application thereof. The anti-scaling agent of the present invention has the characteristics of wide source of raw materials, simple synthesis process, no pollution and good anti-scaling effect.

[0008] In order to achieve the above objectives:

[0009] The first aspect of the present invention discloses an anti-scaling agent, the anti-scaling agent has the following molecular formula:

[0010]

[0011] Wherein, m = 1000-10000;

[0012] n=200-4000.

[0013] Preferably, the viscosity average molecular weight of the antiscalant is 100,000-300,000.

[0014] In another aspect, the present invention discloses a method for preparing an anti-scaling agent, and the specific steps of the preparation method are as follows:

[0015] (1) adding iminobis(methylphosphonic acid), 1,4-dichloro-2-butene, and ethanol to a four-necked flask, adjusting the pH to 9-10 with a sodium hydroxide solution, heating and keeping the temperature for reaction, and maintaining the pH at 9-10 with a sodium hydroxide solution during the reaction; cooling to below 50° C., adding 2-aminobenzene-1,3,5-tricarboxylic acid, adjusting the pH to 8-9 with a sodium hydroxide solution, heating and refluxing for reaction, and maintaining the pH at 8-9 with a sodium hydroxide solution during the reaction; after the reaction is completed, distilling the mixed liquid under reduced pressure to obtain a viscous solid;

[0016] (2) adding distilled water, stirring to dissolve, adding (2-acrylamidoethyl)phosphonic acid and buffer salt, stirring evenly, and adjusting the pH to 7-8 with sodium hydroxide solution;

[0017] (3) Add the initiator dropwise to the above four-necked flask. After the addition is complete, stir the reaction until the solution begins to become viscous. Raise the temperature to 70°C and continue the reaction for 1-2 hours to obtain a viscous mixed solution. Lower the temperature to below 40°C and adjust the pH to 7-8 with sodium hydroxide.

[0018] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0019] In the present invention, preferably, based on 1 molar part of iminobis(methylphosphonic acid), the molar parts of 1,4-dichloro-2-butene, 2-aminobenzene-1,3,5-tricarboxylic acid and (2-acrylamidoethyl)phosphonic acid are 0.8-1.2:0.8-1.2:0.2-0.4 respectively.

[0020] In the present invention, preferably, the mass ratio of ethanol to iminobis(methylphosphonic acid) in step (1) is 10-15:1.

[0021] In the present invention, preferably, the temperature of the insulation reaction in step (1) is 50-70° C., the time is 1-4 h, and the time of the reflux reaction is 2-6 h.

[0022] In the present invention, preferably, the mass ratio of distilled water to iminobis(methylphosphonic acid) in step (2) is 15-20:1.

[0023] In the present invention, preferably, the buffer salt in step (2) is one of sodium dihydrogen phosphate, potassium dihydrogen phosphate and ammonium dihydrogen phosphate, and the mass ratio of the buffer salt to iminobis(methylphosphonic acid) is 0.1-0.2:1.

[0024] In the present invention, preferably, the initiator in step (3) is a mixed solution of persulfate and sodium bisulfite, wherein the concentration of persulfate is 10-12wt%, the concentration of sodium bisulfite is 3-5wt%, and the mass ratio of the initiator to iminobis(methylphosphonic acid) is 0.2-0.5:1.

[0025] Preferably, the persulfate is one of sodium persulfate and ammonium persulfate.

[0026] The antiscalant synthesis reaction equation of the present invention is as follows:

[0027]

[0028] The third object of the present invention discloses the application of the above-mentioned antiscaling agent in sewage treatment.

[0029] The scale inhibitor of the present invention belongs to a linear polymer compound, so the crystal growth is disturbed and distorted, the crystal becomes fine, the scale layer formed is soft, and it is very easy to be washed away by water flow. The polymer contains a large amount of phosphonic acid in the molecule, has good chelating ability and thermal stability, can form a stable complex with metal ions such as calcium, magnesium, and iron, and prevents the metal ions from combining with anions such as carbonate and sulfate to form scale; contains a large number of carboxyl functional groups, these carboxyl groups can chelate with metal ions such as calcium and magnesium in water to form a stable water-soluble complex, and prevent metal ions from forming scale precipitation. At the same time, the polycarboxylic acid polymer also has a dispersing effect, which can disperse the already formed tiny particles in the water to prevent them from aggregating to form large scale blocks.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] (1) The raw materials of the scale inhibitor of the present invention are widely available, the synthesis process is simple, the synthesis method is a one-pot process, there are no by-products, and there is no environmental pollution;

[0032] (2) The scale inhibitor of the present invention has a good scale inhibition effect. When the concentration is 3 mg / L, the scale inhibition rate is 90% or more; when the concentration is 5 mg / L, the scale inhibition rate can reach more than 93%; when the concentration is 8 mg / L, the scale inhibition rate can reach more than 96%. DETAILED DESCRIPTION

[0033] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0034] The present invention will be further described below in conjunction with specific embodiments:

[0035] Example 1

[0036] (1) Add 50mmol of iminobis(methylphosphonic acid), 40mmol of 1,4-dichloro-2-butene, and 102.5g of ethanol to a four-necked flask, adjust the pH to 9-10 with sodium hydroxide solution, heat to 60°C, and keep the temperature for 1 hour. During the reaction, use sodium hydroxide solution to maintain the pH at 9-10. Cool down to below 50°C, add 45mmol of 2-aminobenzene-1,3,5-tricarboxylic acid, adjust the pH to 8-9 with sodium hydroxide solution, heat and reflux for 2 hours, and use sodium hydroxide solution to maintain the pH at 8-9. After the reaction is completed, the mixed liquid is distilled under reduced pressure to obtain a viscous solid.

[0037] (2) Add 153.75 g of distilled water, stir to dissolve, add 10 mmol (2-acrylamidoethyl)phosphonic acid and 1.03 g of sodium dihydrogen phosphate, stir evenly, and adjust the pH to 7-8 with sodium hydroxide solution.

[0038] (3) 2.05 g of initiator was added dropwise to the above four-necked flask. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 12 wt % and the concentration of sodium bisulfite was 5 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 1 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide.

[0039] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0040] Example 2

[0041] (1) Add 50 mmol of iminobis(methylphosphonic acid), 60 mmol of 1,4-dichloro-2-butene, and 142.5 g of ethanol to a four-necked flask, adjust the pH to 9-10 with sodium hydroxide solution, heat to 50°C, and keep the temperature for 4 hours. During the reaction, use sodium hydroxide solution to maintain the pH at 9-10. Cool down to below 50°C, add 40 mmol of 2-aminobenzene-1,3,5-tricarboxylic acid, adjust the pH to 8-9 with sodium hydroxide solution, heat and reflux for 3 hours, and use sodium hydroxide solution to maintain the pH at 8-9. After the reaction is completed, the mixed liquid is distilled under reduced pressure to obtain a viscous solid.

[0042] (2) Add 169 g of distilled water, stir to dissolve, add 20 mmol (2-acrylamidoethyl)phosphonic acid and 1.44 g of sodium dihydrogen phosphate, stir evenly, and adjust the pH to 7-8 with sodium hydroxide solution.

[0043] (3) 3.46 g of initiator was added dropwise to the above four-necked flask. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 11 wt % and the concentration of sodium bisulfite was 4 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 2 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide.

[0044] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0045] Example 3

[0046] (1) Add 50 mmol of iminobis(methylphosphonic acid), 44 mmol of 1,4-dichloro-2-butene, and 138 g of ethanol to a four-necked flask, adjust the pH to 9-10 with sodium hydroxide solution, heat to 70°C, and keep the temperature for 1 hour. During the reaction, use sodium hydroxide solution to maintain the pH at 9-10. Cool down to below 50°C, add 60 mmol of 2-aminobenzene-1,3,5-tricarboxylic acid, adjust the pH to 8-9 with sodium hydroxide solution, heat and reflux for 4 hours, and use sodium hydroxide solution to maintain the pH at 8-9. After the reaction is completed, the mixed liquid is distilled under reduced pressure to obtain a viscous solid.

[0047] (2) Add 188 g of distilled water, stir to dissolve, add 18 mmol (2-acrylamidoethyl)phosphonic acid and 1.68 g of potassium dihydrogen phosphate, stir evenly, and adjust the pH to 7-8 with sodium hydroxide solution.

[0048] (3) 2.88 g of initiator was added dropwise to the above four-necked flask. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 12 wt % and the concentration of sodium bisulfite was 4 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 1.5 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide.

[0049] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0050] Example 4

[0051] (1) Add 50 mmol of iminobis(methylphosphonic acid), 48 mmol of 1,4-dichloro-2-butene, and 153 g of ethanol to a four-necked flask, adjust the pH to 9-10 with sodium hydroxide solution, heat to 65°C, and keep the temperature for 2 hours. During the reaction, use sodium hydroxide solution to maintain the pH at 9-10. Cool down to below 50°C, add 55 mmol of 2-aminobenzene-1,3,5-tricarboxylic acid, adjust the pH to 8-9 with sodium hydroxide solution, heat and reflux for 4 hours, and use sodium hydroxide solution to maintain the pH at 8-9. After the reaction is completed, the mixed liquid is distilled under reduced pressure to obtain a viscous solid.

[0052] (2) Add 205 g of distilled water, stir to dissolve, add 16 mmol (2-acrylamidoethyl)phosphonic acid and 1.03 g of sodium dihydrogen phosphate, stir evenly, and adjust the pH to 7-8 with sodium hydroxide solution.

[0053] (3) 3.66 g of initiator was added dropwise to the above four-necked flask. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 11 wt % and the concentration of sodium bisulfite was 5 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 1.2 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide.

[0054] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0055] Example 5

[0056] (1) Add 50 mmol of iminobis(methylphosphonic acid), 55 mmol of 1,4-dichloro-2-butene, and 153.5 g of ethanol to a four-necked flask, adjust the pH to 9-10 with sodium hydroxide solution, heat to 65°C, and keep the temperature for 2 hours. During the reaction, use sodium hydroxide solution to maintain the pH at 9-10. Cool down to below 50°C, add 43 mmol of 2-aminobenzene-1,3,5-tricarboxylic acid, adjust the pH to 8-9 with sodium hydroxide solution, heat and reflux for 5 hours, and use sodium hydroxide solution to maintain the pH at 8-9. After the reaction is completed, the mixed liquid is distilled under reduced pressure to obtain a viscous solid.

[0057] (2) Add 200 g of distilled water, stir to dissolve, add 14 mmol (2-acrylamidoethyl)phosphonic acid and 1.7 g of potassium dihydrogen phosphate, stir evenly, and adjust the pH to 7-8 with sodium hydroxide solution.

[0058] (3) 3.88 g of initiator was added dropwise to the above four-necked flask. The initiator was a mixture of ammonium persulfate and sodium bisulfite, wherein the concentration of ammonium persulfate was 10 wt % and the concentration of sodium bisulfite was 3 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 1.8 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide.

[0059] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0060] Example 6

[0061] (1) Add 50 mmol of iminobis(methylphosphonic acid), 52 mmol of 1,4-dichloro-2-butene, and 150 g of ethanol to a four-necked flask, adjust the pH to 9-10 with sodium hydroxide solution, heat to 60°C, and keep the temperature for 3 hours. During the reaction, use sodium hydroxide solution to maintain the pH at 9-10. Cool down to below 50°C, add 50 mmol of 2-aminobenzene-1,3,5-tricarboxylic acid, adjust the pH to 8-9 with sodium hydroxide solution, heat under reflux for 6 hours, and use sodium hydroxide solution to maintain the pH at 8-9. After the reaction is completed, the mixed liquid is distilled under reduced pressure to obtain a viscous solid.

[0062] (2) Add 186 g of distilled water, stir to dissolve, add 12 mmol (2-acrylamidoethyl)phosphonic acid and 1.8 g of sodium dihydrogen phosphate, stir evenly, and adjust the pH to 7-8 with sodium hydroxide solution.

[0063] (3) 1.88 g of initiator was added dropwise to the above four-necked flask. The initiator was a mixture of ammonium persulfate and sodium bisulfite, wherein the concentration of ammonium persulfate was 10 wt % and the concentration of sodium bisulfite was 3 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 1.6 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide.

[0064] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0065] Example 7

[0066] (1) Add 50 mmol of iminobis(methylphosphonic acid), 50 mmol of 1,4-dichloro-2-butene, and 138 g of ethanol to a four-necked flask, adjust the pH to 9-10 with sodium hydroxide solution, heat to 60°C, and keep the temperature for 3 hours. During the reaction, use sodium hydroxide solution to maintain the pH at 9-10. Cool to below 50°C, add 52 mmol of 2-aminobenzene-1,3,5-tricarboxylic acid, adjust the pH to 8-9 with sodium hydroxide solution, heat and reflux for 5 hours, and use sodium hydroxide solution to maintain the pH at 8-9. After the reaction is completed, the mixed liquid is distilled under reduced pressure to obtain a viscous solid.

[0067] (2) Add 190 g of distilled water, stir to dissolve, add 12 mmol (2-acrylamidoethyl)phosphonic acid and 1.92 g of sodium dihydrogen phosphate, stir evenly, and adjust the pH to 7-8 with sodium hydroxide solution.

[0068] (3) 5.13 g of initiator was added dropwise to the above four-necked flask. The initiator was a mixture of sodium persulfate and sodium bisulfite, wherein the concentration of sodium persulfate was 10 wt % and the concentration of sodium bisulfite was 4 wt %. After the addition was completed, the mixture was stirred and reacted until the solution began to become viscous. The mixture was heated to 70° C. and kept warm for 2 h to obtain a viscous mixed solution. The mixture was cooled to below 40° C. and the pH was adjusted to 7-8 with sodium hydroxide.

[0069] (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent.

[0070] Example 8 Evaluation of scale inhibition effect

[0071] The scale inhibitors of the present invention (Examples 1-7) were evaluated indoors, and the evaluation method was based on GB / T 16632-2019 "Determination of scale inhibition performance of water treatment agents - calcium carbonate deposition method". The dosage of the scale inhibitor was 3, 5, and 8 mg / L, and the circulating water of a chemical plant was used as the evaluation water, and EDTA was used as a comparative sample. The test results are shown in Table 1.

[0072] Table 1 Determination results of scale inhibition rate of scale inhibitor (%)

[0073] 3mg / L 5mg / L 8mg / L Example 1 90 93.9 96.3 Example 2 90.5 94 96.5 Example 3 90.5 94.2 96.6 Example 4 90.2 94 96.7 Example 5 90.4 94.2 96.7 Example 6 91 94.5 96.9 Example 7 90.8 94.3 96.8 Comparative Example 58 73 81.9

[0074] From Table 1 we can see that:

[0075] (1) When the antiscalant of the present invention (Examples 1-7) is used at a concentration of 3 mg / L, the antiscaling rate is 90% or more, and the highest is 91% (Example 6), while the comparative example is 58%, which is significantly lower than the present invention;

[0076] (2) When the antiscalant of the present invention (Examples 1-7) is used at a concentration of 5 mg / L, the antiscaling rate is above 93%, with the highest reaching 94.5% (Example 6), while the comparative example is 73%, which is significantly lower than the present invention;

[0077] (3) When the antiscalant of the present invention (Examples 1-7) was used at a concentration of 8 mg / L, the antiscaling rate was above 96%, with the highest reaching 96.9% (Example 6), while the comparative example was 81.9%, which was significantly lower than the present invention;

[0078] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0079] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0080] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing an antiscaling agent, characterized in that: The specific steps of the preparation method are as follows: (1) adding iminobis(methylphosphonic acid), 1,4-dichloro-2-butene, and ethanol to a four-necked flask, adjusting the pH to 9-10 with a sodium hydroxide solution, heating and keeping the temperature for reaction, and maintaining the pH at 9-10 with a sodium hydroxide solution during the reaction; cooling to below 50° C., adding 2-aminobenzene-1,3,5-tricarboxylic acid, adjusting the pH to 8-9 with a sodium hydroxide solution, heating and refluxing for reaction, and maintaining the pH at 8-9 with a sodium hydroxide solution during the reaction; after the reaction is completed, distilling the mixed liquid under reduced pressure to obtain a viscous solid; (2) adding distilled water, stirring to dissolve, adding (2-acrylamidoethyl)phosphonic acid and buffer salt, stirring evenly, and adjusting the pH to 7-8 with sodium hydroxide solution; (3) Add the initiator dropwise to the above four-necked flask. After the addition is complete, stir the reaction until the solution begins to become viscous. Raise the temperature to 70°C and continue the reaction for 1-2 hours to obtain a viscous mixed solution. Lower the temperature to below 40°C and adjust the pH to 7-8 with sodium hydroxide. (4) drying and granulating the viscous mixed liquid to obtain a product antiscaling agent; Based on 1 molar part of iminobis(methylphosphonic acid), the molar parts of 1,4-dichloro-2-butene, 2-aminobenzene-1,3,5-tricarboxylic acid and (2-acrylamidoethyl)phosphonic acid are 0.8-1.2:0.8-1.2:0.2-0.4 respectively.

2. The preparation method according to claim 1, characterized in that: The mass ratio of ethanol to iminobis(methylphosphonic acid) in step (1) is 10-15:

1.

3. The preparation method according to claim 1, characterized in that: The temperature of the insulation reaction in step (1) is 50-70° C., the time is 1-4 h, and the time of the reflux reaction is 2-6 h.

4. The preparation method according to claim 1, characterized in that: The mass ratio of distilled water to iminobis(methylphosphonic acid) in step (2) is 15-20:

1.

5. The preparation method according to claim 1, characterized in that: The buffer salt in step (2) is one of sodium dihydrogen phosphate, potassium dihydrogen phosphate and ammonium dihydrogen phosphate, and the mass ratio of the buffer salt to iminobis(methylphosphonic acid) is 0.1-0.2:

1.

6. The preparation method according to claim 1, characterized in that: The initiator in step (3) is a mixed solution of persulfate and sodium bisulfite, wherein the concentration of persulfate is 10-12wt%, the concentration of sodium bisulfite is 3-5wt%, and the mass ratio of the initiator to iminobis(methylphosphonic acid) is 0.2-0.5:

1.

7. The preparation method according to claim 1, characterized in that: The persulfate is one of sodium persulfate and ammonium persulfate.

8. An antiscaling agent, characterized in that The antiscalant molecular formula is as follows: Wherein, m = 1000-10000; n＝200-4000。 9. The antiscaling agent according to claim 8, characterized in that: The viscosity average molecular weight of the anti-scaling agent is 100,000-300,000.

10. Use of the antiscaling agent according to claim 8 or 9 in sewage treatment.

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