An environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant, its preparation method and application

Abstract

This invention belongs to the field of water treatment technology, and proposes an environmentally friendly, phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant, its preparation method, and its application. By mass, this environmentally friendly, phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant is composed of 18-22 parts itaconic acid-hydroxyethyl acrylate copolymer, 20-30 parts polyepoxysuccinic acid, 90-110 parts sodium gluconate, and 7-10 parts zinc sulfate heptahydrate. The product provided by this invention requires a small dosage and possesses excellent scale inhibition, dispersing, corrosion inhibition, and biodegradability properties, exhibiting superior overall performance. Furthermore, it is phosphorus-free and nitrogen-free, avoiding the eutrophication problem caused by long-term use of chemical agents.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, and relates to an environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant, its preparation method and application. Background Technology

[0002] Currently, most water treatment agents used for industrial circulating cooling water are phosphorus-based formulations. However, because their components contain phosphorus or nitrogen or are not biodegradable, long-term use can easily lead to eutrophication of water bodies. It is an inevitable trend for such formulations to be replaced by phosphorus-free and nitrogen-free environmentally friendly agents.

[0003] While natural polymers are inexpensive and readily available, they have poor scale inhibition effects and high impurity content. Therefore, low-phosphorus and environmentally friendly synthetic polymer scale inhibitors have gained widespread attention, such as phosphorus-free synthetic organic polymers like polyacrylic acid and polymethacrylic acid. However, their limited functional groups result in limited treatment capacity, and these polymers are non-biodegradable, leading to severe environmental impacts with long-term use. Among them, Chinese invention patent with publication number CN115536161A discloses an environmentally friendly phosphorus-free scale inhibitor and dispersant with excellent corrosion inhibition performance, which is composed of sodium itaconic acid-methpropylene sulfonate, polyepoxysuccinic acid, sodium gluconate and alkylolamide in a mass ratio of 32-47:10-20:98-102:8-12. However, this scale inhibitor and dispersant requires a large amount and contains nitrogen, so it is not environmentally friendly. Chinese invention patent with publication number CN 117327232A discloses a phosphorus-free, non-nitrogen-free green water treatment agent and its preparation method and application. It is obtained by copolymerization of epoxysuccinic acid, itaconic acid and hydroxyethyl acrylate, wherein the molar ratio of epoxysuccinic acid, itaconic acid and hydroxyethyl acrylate is 1.8-2.1:1.8-2.1:1. The biodegradability of this water treatment agent needs to be improved.

[0004] Therefore, it is of great significance to develop phosphorus- and nitrogen-free green water treatment agents with excellent scale inhibition, dispersion, corrosion inhibition and biodegradation properties. Summary of the Invention

[0005] This invention proposes an environmentally friendly, phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant, its preparation method, and its application. While requiring a small dosage, it possesses excellent scale inhibition, dispersion, corrosion inhibition, and biodegradability properties, exhibiting superior overall performance. Furthermore, being phosphorus-free and nitrogen-free, it avoids the eutrophication problem caused by long-term use of chemicals.

[0006] The technical solution of this invention is implemented as follows:

[0007] An environmentally friendly, phosphorus-free, nitrogen-free scale inhibitor and corrosion dispersant, by weight, is composed of 18-22 parts itaconic acid-hydroxyethyl acrylate copolymer, 20-30 parts polyepoxysuccinic acid, 90-110 parts sodium gluconate and 7-10 parts zinc sulfate heptahydrate.

[0008] Preferably, the product comprises, by weight, 20 parts itaconic acid-hydroxyethyl acrylate copolymer, 25 parts polyepoxysuccinic acid, 100 parts sodium gluconate and 8.83 parts zinc sulfate heptahydrate.

[0009] Preferably, the average molecular weight of the polyepoxysuccinic acid is 900-1000.

[0010] Preferably, the polyepoxysuccinic acid has an average molecular weight of 950.

[0011] Preferably, the preparation method of the itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0012] Deionized water and tert-butanol were added to itaconic acid and hydroxyethyl acrylate in a molar ratio of 2.8-3.2:1, and the mixture was heated to 60-70°C while nitrogen gas was introduced. Then, potassium persulfate solution and sodium sulfite solution were added dropwise simultaneously. After the addition was complete, the temperature was further increased to 80-90°C, and the reaction was allowed to proceed for 2.5-3.5 hours to obtain a light yellow, transparent IA-HEA polymerization solution. The itaconic acid-hydroxyethyl acrylate copolymer prepared in this invention has a molecular weight of 15,000-20,000.

[0013] Preferably, the molar ratio of itaconic acid to hydroxyethyl acrylate is 3:1.

[0014] Preferably, the amount of deionized water added is 80-120% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0015] Preferably, the amount of tert-butanol added is 12-18% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0016] Preferably, the amount of potassium persulfate added is 5-10% of the total mass of itaconic acid and hydroxyethyl acrylate, and the molar ratio of sodium sulfite to potassium persulfate is 0.8-1.2:1.8-2.2.

[0017] Preferably, the mass concentration of both the potassium persulfate solution and the sodium sulfite solution is 10%; the dropping time of the potassium persulfate solution and the sodium sulfite solution is 0.5-1h.

[0018] The present invention also provides a method for preparing the environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant as described above, comprising the following steps: mixing itaconic acid-hydroxyethyl acrylate copolymer, polyepoxysuccinic acid, sodium gluconate and zinc sulfate heptahydrate according to the specified ratio.

[0019] On the other hand, the environmentally friendly phosphorus-free and nitrogen-free scale inhibitors and corrosion dispersants described above can be used in industrial circulating cooling water treatment.

[0020] The working principle and beneficial effects of this invention are as follows:

[0021] 1. In this invention, polyepoxysuccinic acid, itaconic acid-hydroxyethyl acrylate copolymer, sodium gluconate, and zinc sulfate heptahydrate interact with each other through a compatible synergistic mechanism. The synergistic effect among the components ensures the speed and density of film formation on carbon steel surfaces, improves the scale inhibition, dispersion, and corrosion inhibition effects of the agent, and at the same time, due to the synergistic effect among the components of the compound agent, the amount of agent used is reduced, the cost is lowered, and the environmental impact is reduced; moreover, the product is phosphorus-free and nitrogen-free, avoiding the eutrophication problem of water bodies caused by long-term use of the agent.

[0022] 2. Characteristics of each monomer component in this invention: (1) Polyepoxysuccinic acid has excellent scale inhibition and corrosion inhibition properties, as well as good biocompatibility and biodegradability. It is a phosphorus-free and nitrogen-free, environmentally friendly agent. (2) Itaconic acid-hydroxyethyl acrylate copolymer is a phosphorus-free, nitrogen-free, biodegradable, environmentally friendly agent with excellent scale inhibition, dispersion and corrosion inhibition properties. (3) Sodium gluconate has a good complexing ability for calcium, magnesium, iron and copper ions in water and has an activating effect on many salts of these ions. Therefore, it has scale inhibition and corrosion inhibition effects and excellent biodegradability. (4) Zinc salt is a precipitation film type corrosion inhibitor. Considering Zn 2+ Emission requirements, Zn in the formula 2+ The concentration is approximately 2 mg / L (i.e., the concentration of zinc sulfate heptahydrate is approximately 8.83 mg / L). The polyepoxysuccinic acid and itaconic acid-hydroxyethyl acrylate copolymer exhibit a synergistic effect, further enhancing the scale inhibition and dispersion effect of the agent and reducing under-deposit corrosion in the water treatment system. Zinc sulfate heptahydrate, in synergy with other components, further improves the corrosion inhibition performance of the agent.

[0023] 3. In the preparation of itaconic acid-hydroxyethyl acrylate copolymer, each reagent plays an irreplaceable role in the reaction. Tert-butanol acts as a chain transfer agent to adjust the molecular weight of the polymer. Sodium sulfite acts as a reducing agent, and when used in combination with potassium persulfate, it initiates a free radical polymerization reaction. Furthermore, its strong reducing ability is beneficial for generating more active centers and increasing the reaction rate. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The substances used in the following embodiments and comparative examples can all be purchased commercially.

[0025] Example 1

[0026] A method for preparing an environmentally friendly, phosphorus-free, nitrogen-free scale inhibitor and corrosion dispersant includes the following steps: mixing 20 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 25 parts by mass of polyepoxysuccinic acid, 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0027] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0028] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 3:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 100% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 15% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0029] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 65°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0030] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 7% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to potassium persulfate was 1:2. The dropping rate was set so that both solutions were added simultaneously within 0.5 hours.

[0031] The temperature was then raised to 85°C and reacted for 3 hours. After cooling to room temperature, the product was discharged to obtain a light yellow and transparent IA-HEA polymer solution, which is itaconic acid-hydroxyethyl acrylate copolymer with an average molecular weight of 17710.

[0032] Example 2

[0033] A method for preparing an environmentally friendly, phosphorus-free, nitrogen-free scale inhibitor and corrosion dispersant includes the following steps: mixing 18 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 30 parts by mass of polyepoxysuccinic acid, 90 parts by mass of sodium gluconate and 10 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0034] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0035] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 2.8:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 120% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 12% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0036] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 70°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0037] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 5% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to potassium persulfate was 1.2:1.8. The dropping rate was set so that the two solutions were added simultaneously within 1 hour.

[0038] The temperature was then raised to 80°C and reacted for 3.5 hours. After cooling to room temperature, the product was discharged to obtain a light yellow and transparent IA-HEA polymerization solution, which is itaconic acid-hydroxyethyl acrylate copolymer with an average molecular weight of 18,100.

[0039] Example 3

[0040] A method for preparing an environmentally friendly, phosphorus-free, nitrogen-free scale inhibitor and corrosion dispersant includes the following steps: mixing 22 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 20 parts by mass of polyepoxysuccinic acid, 110 parts by mass of sodium gluconate and 7 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0041] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0042] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 3.2:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 80% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 18% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0043] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 60°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0044] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 10% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to potassium persulfate was 0.8:2.2. The dropping rate was set so that the two solutions were added simultaneously within 0.5 hours.

[0045] The temperature was then raised to 90°C and reacted for 2.5 hours. After cooling to room temperature, the product was discharged to obtain a light yellow and transparent IA-HEA polymer solution, which is itaconic acid-hydroxyethyl acrylate copolymer with an average molecular weight of 16,800.

[0046] Comparative Example 1

[0047] A method for preparing a water treatment agent includes the following steps: mixing 25 parts by mass of polyepoxysuccinic acid, 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0048] Comparative Example 2

[0049] A method for preparing a water treatment agent includes the following steps: mixing 20 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate;

[0050] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0051] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 3:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 100% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 15% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0052] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 65°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0053] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 7% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to potassium persulfate was 1:2. The dropping rate was set so that both solutions were added simultaneously within 0.5 hours.

[0054] The temperature was then raised to 85°C and reacted for 3 hours. After cooling to room temperature, the product was discharged to obtain a light yellow and transparent IA-HEA polymer solution, which is itaconic acid-hydroxyethyl acrylate copolymer with an average molecular weight of 17710.

[0055] Comparative Example 3

[0056] A method for preparing a water treatment agent includes the following steps: mixing 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate.

[0057] Comparative Example 4

[0058] A method for preparing a water treatment agent includes the following steps: mixing 20 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 25 parts by mass of polyepoxysuccinic acid and 100 parts by mass of sodium gluconate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0059] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0060] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 3:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 100% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 15% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0061] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 65°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0062] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 7% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to potassium persulfate was 1:2. The dropping rate was set so that both solutions were added simultaneously within 0.5 hours.

[0063] The temperature was then raised to 85°C and reacted for 3 hours. After cooling to room temperature, the product was discharged to obtain a light yellow and transparent IA-HEA polymer solution, which is itaconic acid-hydroxyethyl acrylate copolymer with an average molecular weight of 17710.

[0064] Comparative Example 5

[0065] A method for preparing a water treatment agent includes the following steps: mixing 20 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 25 parts by mass of polyepoxysuccinic acid, 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0066] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0067] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 2:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 100% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 15% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0068] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 65°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0069] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 7% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to potassium persulfate was 1:2. The dropping rate was set so that both solutions were added simultaneously within 0.5 hours.

[0070] The temperature was then raised to 85°C and reacted for 3 hours. After cooling to room temperature, the product was discharged, yielding a light yellow and transparent IA-HEA polymer solution, which is the itaconic acid-hydroxyethyl acrylate copolymer.

[0071] Comparative Example 6

[0072] A method for preparing a water treatment agent includes the following steps: mixing 20 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 25 parts by mass of polyepoxysuccinic acid, 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0073] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0074] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 3:1 were added, followed by deionized water and isopropanol. The amount of deionized water added was 100% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of isopropanol added was 15% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0075] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 65°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0076] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 7% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to potassium persulfate was 1:2. The dropping rate was set so that both solutions were added simultaneously within 0.5 hours.

[0077] The temperature was then raised to 85°C and reacted for 3 hours. After cooling to room temperature, the product was discharged, yielding a light yellow and transparent IA-HEA polymer solution, which is the itaconic acid-hydroxyethyl acrylate copolymer.

[0078] Comparative Example 7

[0079] A method for preparing a water treatment agent includes the following steps: mixing 20 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 25 parts by mass of polyepoxysuccinic acid, 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0080] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0081] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 3:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 100% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 15% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0082] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 65°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0083] Two syringe pumps were used to simultaneously add ammonium persulfate solution and sodium sulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 7% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium sulfite to ammonium persulfate was 1:2. The dropping rate was set so that both solutions were added simultaneously within 0.5 hours.

[0084] The temperature was then raised to 85°C and reacted for 3 hours. After cooling to room temperature, the product was discharged, yielding a light yellow and transparent IA-HEA polymer solution, which is the itaconic acid-hydroxyethyl acrylate copolymer.

[0085] Comparative Example 8

[0086] A method for preparing a water treatment agent includes the following steps: mixing 20 parts by mass of itaconic acid-hydroxyethyl acrylate copolymer, 25 parts by mass of polyepoxysuccinic acid, 100 parts by mass of sodium gluconate and 8.83 parts by mass of zinc sulfate heptahydrate; wherein the average molecular weight of the polyepoxysuccinic acid is 950.

[0087] The preparation method of itaconic acid-hydroxyethyl acrylate copolymer includes the following steps:

[0088] In a four-necked flask equipped with a condenser and thermometer, itaconic acid (IA) and hydroxyethyl acrylate (HEA) in a molar ratio of 3:1 were added, followed by deionized water and tert-butanol. The amount of deionized water added was 100% of the total mass of itaconic acid and hydroxyethyl acrylate, and the amount of tert-butanol added was 15% of the total mass of itaconic acid and hydroxyethyl acrylate.

[0089] Place the four-necked bottle into an oil bath equipped with a stirrer, heat it to 65°C, and simultaneously introduce nitrogen gas and turn on the condenser.

[0090] Two syringe pumps were used to simultaneously add potassium persulfate solution and sodium bisulfite solution, both with a mass concentration of 10%. The amount of potassium persulfate added was 7% of the total mass of itaconic acid and hydroxyethyl acrylate. The molar ratio of sodium bisulfite to potassium persulfate was 1:2. The dropping rate was set so that the two solutions were added simultaneously within 0.5 hours.

[0091] The temperature was then raised to 85°C and reacted for 3 hours. After cooling to room temperature, the product was discharged, yielding a light yellow and transparent IA-HEA polymer solution, which is the itaconic acid-hydroxyethyl acrylate copolymer.

[0092] Experimental results example

[0093] The performance of the water treatment agents obtained in Examples 1-3 and Comparative Examples 1-8 was compared. The itaconic acid-hydroxyethyl acrylate copolymer prepared in Example 1 was used as Sample 1 (IA-HEA), polyepoxysuccinic acid as Sample 2 (PESA), and sodium gluconate as Sample 3 (PTT) were also tested. The specific experimental methods are as follows:

[0094] (1) Scale inhibition performance test

[0095] ① Calcium phosphate inhibition:

[0096] Referring to the national standard GB / T22626-2008, distilled water was used to prepare Ca... 2+ The mass concentration is 250 mg / L (calculated as CaCO3), PO4 3- Test water with a concentration of 10 mg / L and pH=9 (adjusted with borax) was taken in a 500 mL Erlenmeyer flask, water treatment agent was added, and the solution was placed in an 80℃ constant temperature water bath for 10 h. After cooling to room temperature, the supernatant was taken and the PO4 content in the solution was determined using a TU-1900 spectrophotometer (710 nm, 1 cm cuvette). 3- The content of [specific element]. Calculate the scale inhibition rate. or 2.

[0097]

[0098] in, C 0、 C 1. C 2 represents the PO4 content in raw water after heating without adding chemicals, after heating with adding chemicals, and at room temperature. 3- The mass concentration, mg / L.

[0099] ②Inhibit calcium carbonate:

[0100] Referring to the national standard GB / T16632-2008, distilled water was used to prepare Ca... 2+ and HCO3 - Test water with concentrations of 600 mg / L and 1200 mg / L (both calculated as CaCO3) was mixed with a water treatment agent and heated in an 80°C constant temperature water bath for 10 h. The CaCO3 concentration was then calculated. 2+ The scale inhibition rate is calculated based on the concentration.

[0101] (2) Dispersion performance test

[0102] A certain amount of water treatment agent and ferrous sulfate were added to the water, and the mixture was stirred vigorously to hydrolyze and oxidize the ferrous ions, simulating the process of iron oxide scale deposition caused by metal corrosion and other reasons in industrial circulating water systems. The reaction is shown below.

[0103]

[0104] FeSO4 hydrolyzes to produce Fe2O3 at high pH as a suspension medium. After standing for a period of time, the light transmittance of the supernatant is measured to determine the dispersion performance of the agent on iron oxide. The better the dispersion performance, the lower the light transmittance.

[0105] (3) Evaluation of corrosion inhibition performance

[0106] This invention conforms to GB / T1875-2000 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotary Coated Plate Corrosion Test Method". The test conditions are: temperature 40℃, rotation speed 80 r / min, no pre-filming of the coated plates, test time 72 h, A3 carbon steel test plates with a surface area of ​​28 cm². 2 The test water was groundwater from a residential area in Shijiazhuang. The water quality analysis results are shown in Table 1.

[0107] Table 1. Water quality analysis results of the test water

[0108]

[0109] (4) Evaluation of biodegradability

[0110] A mixed solution of water treatment agent and microbial inoculum was cultured using a shaker method. The COD of the mixed solution was measured on day 28, and the degradation rate was calculated based on the change in COD. The tested substances were evaluated according to the biodegradability evaluation criteria in Table 2.

[0111] Table 2. Evaluation Criteria for Biodegradability

[0112]

[0113] COD Measurement Test Method:

[0114] Take about 100 g of garden soil and place it in 1 L of distilled water. Stir thoroughly and allow it to settle for 2 hours. Filter the solution and discard about 200 mL of the supernatant. The remaining solution is the solution containing the microbial inoculum. Add 0.5 mL of the inoculum to a conical flask containing a certain concentration of water treatment agent, cap the flask, and place it in a constant temperature (around 25°C) shaker. Measure the COD of the sample on the 28th day of the experiment.

[0115] (5) Results:

[0116] The performance of the water treatment agents obtained in Examples 1-3, Comparative Examples 1-8, and Sample 1-3 was determined and is shown in Table 3.

[0117] Table 3

[0118]

[0119] In Table 3, the dosage for Example 1 was 20 mg / L IA-HEA + 25 mg / L PESA + 100 mg / L PTT + 8.83 mg / L zinc sulfate heptahydrate;

[0120] Example 2 uses 18 mg / L IA-HEA + 30 mg / L PESA + 90 mg / L PTT + 10 mg / L zinc sulfate heptahydrate;

[0121] Example 3 uses 22 mg / L IA-HEA + 20 mg / L PESA + 110 mg / L PTT + 7 mg / L zinc sulfate heptahydrate;

[0122] Comparative Example 1 used 25 mg / L PESA + 100 mg / L PTT + 8.83 mg / L zinc sulfate heptahydrate;

[0123] Comparative Example 2 used 20 mg / L IA-HEA + 100 mg / L PTT + 8.83 mg / L zinc sulfate heptahydrate;

[0124] Comparative Example 3 used 100 mg / L PTT + 8.83 mg / L zinc sulfate heptahydrate;

[0125] Comparative Example 4 used 20 mg / L IA-HEA + 25 mg / L PESA + 100 mg / L PTT;

[0126] The dosage of comparative examples 5-8 is the same as that of example 1.

[0127] IA-HEA represents itaconic acid-hydroxyethyl acrylate copolymer, PESA represents polyepoxysuccinic acid, and PTT represents sodium gluconate.

[0128] Testing showed that the water treatment agent formulations obtained in Examples 1-3 exhibited superior scale inhibition, dispersion, and corrosion inhibition properties compared to the comparative examples, and also demonstrated good biodegradability and ideal overall performance. The itaconic acid-hydroxyethyl acrylate copolymer dispersibility index (PDI, determined by gel permeation chromatography, GPC) in the water treatment agent formulations obtained in Examples 1-3 was approximately 1. In contrast, Comparative Examples 6-8 employed different chain transfer agents, initiators, and redox systems in the preparation of the itaconic acid-hydroxyethyl acrylate copolymer, resulting in polymers with lower average molecular weights and higher dispersibility indexes compared to the itaconic acid-hydroxyethyl acrylate copolymers in Examples 1-3. These polymers showed varying degrees of influence on scale inhibition, dispersion, and corrosion inhibition properties. The reasons for this are: ammonium persulfate and potassium persulfate, as initiators, have different half-lives, leading to different polymerization reaction rates; tert-butanol, as a chain transfer agent, can also adjust the molecular weight; sodium sulfite and potassium persulfate act as redox systems during the polymerization reaction, affecting the reaction rate and ultimately the polymer's molecular weight, thus impacting its scale inhibition, dispersion, and corrosion inhibition properties.

[0129] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly, phosphorus-free, nitrogen-free scale inhibitor and corrosion dispersant, characterized in that, By weight, it consists of 18-22 parts itaconic acid-hydroxyethyl acrylate copolymer, 20-30 parts polyepoxysuccinic acid, 90-110 parts sodium gluconate and 7-10 parts zinc sulfate heptahydrate; The preparation method of the itaconic acid-hydroxyethyl acrylate copolymer includes the following steps: Deionized water and tert-butanol were added to itaconic acid and hydroxyethyl acrylate in a molar ratio of 2.8-3.2:1, and the mixture was heated to 60-70°C while nitrogen gas was introduced. Then, potassium persulfate solution and sodium sulfite solution were added dropwise simultaneously. After the addition was complete, the temperature was raised to 80-90°C and the reaction was allowed to proceed for 2.5-3.5 hours to obtain a light yellow and transparent IA-HEA polymerization solution. The average molecular weight of the polyepoxysuccinic acid is 900-1000, and the molecular weight of the itaconic acid-hydroxyethyl acrylate copolymer is 15000-20000.

2. The environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant according to claim 1, characterized in that, By weight, it consists of 20 parts itaconic acid-hydroxyethyl acrylate copolymer, 25 parts polyepoxysuccinic acid, 100 parts sodium gluconate and 8.83 parts zinc sulfate heptahydrate.

3. The environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant according to claim 1, characterized in that, The amount of deionized water added is 80-120% of the total mass of itaconic acid and hydroxyethyl acrylate.

4. The environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant according to claim 1, characterized in that, The amount of tert-butanol added is 12-18% of the total mass of itaconic acid and hydroxyethyl acrylate.

5. The environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant according to claim 1, characterized in that, The amount of potassium persulfate added is 5-10% of the total mass of itaconic acid and hydroxyethyl acrylate, and the molar ratio of sodium sulfite to potassium persulfate is 0.8-1.2:1.8-2.

2.

6. The environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant according to claim 1, characterized in that, The mass concentration of both the potassium persulfate solution and the sodium sulfite solution is 10%; the dropping time of the potassium persulfate solution and the sodium sulfite solution is 0.5-1h.

7. A method for preparing an environmentally friendly, phosphorus-free, nitrogen-free scale inhibitor and corrosion dispersant as described in any one of claims 1-6, characterized in that, Includes the following steps: Mix itaconic acid-hydroxyethyl acrylate copolymer, polyepoxysuccinic acid, sodium gluconate and zinc sulfate heptahydrate according to the specified ratio.

8. The application of an environmentally friendly phosphorus-free and nitrogen-free scale inhibitor and corrosion dispersant as described in any one of claims 1-6 in industrial circulating cooling water treatment.

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