High-efficiency environment-friendly scale inhibitor and preparation method thereof

Abstract

The application belongs to the technical field of water pollution prevention and treatment agents, and provides a high-efficiency environment-friendly scale inhibitor and a preparation method. The scale inhibitor is a non-phosphorus water treatment scale inhibitor, and comprises sodium polyepoxysuccinate, sodium polyaspartate, a sulfonic acid group-containing acrylic acid copolymer, sodium gluconate, sodium tetraborate and polyethylene glycol. In the preparation, the sulfonic acid group-containing acrylic acid copolymer, the sodium polyepoxysuccinate and the sodium polyaspartate are first prepared into a polymer base solution, then the sodium gluconate, the sodium tetraborate and the polyethylene glycol are prepared into a boron-containing polyhydroxy auxiliary dispersing solution, the auxiliary dispersing solution is added into the polymer base solution, and the product is obtained through adjustment, standing defoaming and filtration. The application reduces the risk of early consumption of carboxyl type scale inhibition components by calcium ions and silicate species in high-hardness silicon-containing industrial reuse water, inhibits the dense deposition of silicon-calcium composite scale, maintains the sustained dispersion capacity, and is suitable for water pollution prevention and treatment processes such as industrial circulating water, industrial wastewater reuse, reverse osmosis concentration reduction and reclaimed water reuse.

Description

Technical Field

[0001] This invention belongs to the field of water pollution control agents technology, and relates to a highly efficient and environmentally friendly scale inhibitor and its preparation method. Background Technology

[0002] In industrial wastewater reuse, reverse osmosis concentration and emission reduction, and circulating cooling water systems, the concentrations of calcium ions, bicarbonate, sulfate, and soluble silicates increase after water concentration, easily leading to the formation of calcium carbonate, calcium sulfate, silica scale, and calcium-silica composite scale. Existing phosphorus-free environmentally friendly scale inhibitors typically rely on carboxyl and hydroxyl groups to adsorb, complex, and disperse scale crystals. However, in high-hardness, silica-containing water systems, these polar groups easily co-precipitate or entrain calcium ions and silica species, causing the effective action sites of the scale inhibitor to be consumed prematurely, making it difficult to maintain a sustained dispersion and inhibition effect on calcium-silica composite scale.

[0003] Therefore, the problem with existing phosphorus-free environmentally friendly scale inhibitors is that in high-hardness, silicon-containing industrial recycled water systems, carboxylic acid or hydroxyl scale inhibitors are prone to co-precipitation or entrainment deposition with calcium ions and silica species, causing the effective action sites originally used for adsorption and dispersion of scale crystals to be consumed prematurely. This results in the formation of a dense deposition layer with silicon-calcium composite scale as the core on the membrane surface, heat exchange surface, or pipeline, thereby reducing the continuous dispersion ability of the scale inhibitor. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a highly efficient and environmentally friendly scale inhibitor and its preparation method. The scale inhibitor comprises a phosphorus-free polycarboxylic acid scale inhibitor component, a sulfonic acid-containing dispersing component, a polyhydroxyl-containing co-dispersing component, sodium tetraborate, and polyethylene glycol. During preparation, a polymer-based liquid and a boron-containing polyhydroxyl-containing co-dispersing liquid are formed separately, followed by mixing, adjustment, static degassing, and filtration. This scale inhibitor can slow down the premature consumption of effective action sites and inhibit the dense deposition of silicon-calcium composite scale, making it suitable for water pollution control and treatment processes.

[0005] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a highly efficient and environmentally friendly scale inhibitor, which is a phosphorus-free water treatment scale inhibitor, comprising, by mass of effective components, sodium polyepoxysuccinate, sodium polyaspartate, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, sodium gluconate, sodium tetraborate and polyethylene glycol, wherein the mass ratio of the above components is (18-30):(10-20):(18-32):(8-18):(0.8-3.5):(3-8), wherein the sodium tetraborate is calculated as anhydrous sodium tetraborate.

[0006] Preferably, the scale inhibitor is an aqueous composition, and the scale inhibitor has a solid content of 25-40 wt.% and a pH of 7.8-9.0.

[0007] Preferably, the scale inhibitor does not contain organic phosphonates and inorganic phosphates.

[0008] Preferably, the limiting viscosity (30°C) of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 0.055-0.100 dL / g.

[0009] Preferably, the relative molecular mass of the sodium polyepoxysuccinate is 400-1500, and the relative molecular mass of the sodium polyaspartate is 1000-5000.

[0010] Preferably, the polyethylene glycol is PEG-300, PEG-400, PEG-600 or PEG-800.

[0011] Preferably, the sodium tetraborate is anhydrous sodium tetraborate, sodium tetraborate pentahydrate, or sodium tetraborate decahydrate.

[0012] Secondly, the present invention provides a method for preparing the high-efficiency and environmentally friendly scale inhibitor described in the first aspect, comprising the following steps: S1, mix acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, sodium polyepoxysuccinate, sodium polyaspartate and water, and stir to obtain polymer base liquid; S2, Sodium gluconate, sodium tetraborate, polyethylene glycol and water are mixed and stirred under alkaline conditions to obtain a boron-containing polyhydroxyl co-dispersant; S3, add the boron-containing polyhydroxyl co-dispersant to the polymer base liquid, stir and mix to obtain a composite scale inhibitor; S4. Adjust the solid content and pH of the composite scale inhibitor, and after standing to defoam and filter, obtain a high-efficiency and environmentally friendly scale inhibitor.

[0013] Preferably, in S1, the acrylic-2-acrylamide-2-methylpropanesulfonic acid copolymer is first mixed with water, and then sodium polyepoxysuccinate and sodium polyaspartate are added. The stirring temperature is 25-45℃ and the stirring time is 30-90 min. The mass ratio of the acrylic-2-acrylamide-2-methylpropanesulfonic acid copolymer to water is (18-32):(50-110).

[0014] Preferably, in S2, the alkaline conditions are pH 8.0-9.0, the stirring temperature is 25-40℃, and the stirring time is 20-60 min.

[0015] Preferably, in step S2, sodium gluconate and sodium tetraborate are first added to water and stirred to dissolve, then polyethylene glycol is added and stirring is continued; the mass ratio of sodium gluconate to water is (8-18):(25-80).

[0016] Preferably, in step S3, the boron-containing polyhydroxy dispersant is added to the polymer base liquid by dropwise addition for 20-60 minutes, and the temperature during the dropwise addition is 25-45°C.

[0017] Preferably, in step S3, after the boron-containing polyhydroxy dispersant is added, stirring continues for 30-90 minutes.

[0018] Preferably, in step S4, the settling and degassing time is 0.5-2 hours, and the filtration is carried out using an 80-120 mesh sieve.

[0019] Acrylic acid-diacrylamide-dimethylpropanesulfonic acid copolymer forms polyanionic segments with carboxylate and sulfonate groups in water. The sulfonate groups are less likely to form insoluble complexes with calcium ions in hard water, maintaining the hydration layer and negative charge repulsion around the segments. Sodium polyepoxysuccinate and sodium polyaspartate provide carboxylate adsorption sites in water. The carboxylate groups can coordinate adsorb with calcium sites on the surface of primary calcium carbonate and calcium sulfate crystal nuclei, covering the growth steps on the crystal surface with polymer chains. This hinders the entry of carbonate, sulfate, and calcium ions into the crystal lattice, shifting crystal growth from regular stacking to defect growth and dispersed suspension. After the polymers first form a polymer base liquid, the sulfonate, carboxylate, and hydration segments are in the same aqueous phase system. The polymer chains remain dispersed through electrostatic repulsion, preventing entanglement and agglomeration of the polycarboxylic acid component due to excessively high local concentrations during subsequent mixing.

[0020] Sodium gluconate exists in the aqueous phase as gluconate ions. Its carboxylate terminus and polyhydroxy segments can reversibly coordinate and hydrogen-bond with calcium ions, borate hydrolysates, and water molecules. Sodium tetraborate forms borate species in the alkaline aqueous phase. These borate species can reversibly complex with adjacent hydroxyl groups in the gluconate ion, causing a rearrangement of the hydration environment near some hydroxyl groups and the carboxylate. This interaction should not be interpreted as the formation of a stable, single-structure intermediate, but rather as the formation of a reversible complexation equilibrium in the boron-containing polyhydroxy co-dispersant. This equilibrium prevents the gluconate ion from directly entering the high-hardness water system as a completely free small-molecule complexing agent, but rather participates in subsequent complexation within the hydration complexation environment formed together with borates and water molecules. The ether oxygen atoms of polyethylene glycol can form a hydrogen-bonded hydration layer with water molecules and associate with gluconate and borate species through hydrogen bonding. This results in a co-dispersant environment characterized by polyhydroxy complexation, hydration segments, and borate equilibrium before the addition of the polymer base liquid to the boron-containing polyhydroxy co-dispersant.

[0021] When the boron-containing polyhydroxy co-dispersant is added dropwise to the polymer base solution, gluconate, borate species, and polyethylene glycol are first diluted and dispersed between the polyanionic segments in the polymer base solution, avoiding excessive association between the boron-containing and polyhydroxy components and the polycarboxylic acid segments in localized areas. During the dropwise addition, the polyhydroxy complexing components in the co-dispersant exchange with the hydration layer surrounding the polymer chains. The polyethylene glycol segments are distributed between the polymer chains, while the gluconate and borate species are distributed in the aqueous phase regions surrounding the sulfonate and carboxylic acid segments. This process creates a dispersion order and localized hydration environment for different functional components in the aqueous phase, rather than irreversible chemical reaction products. Static degassing and filtration remove air bubbles introduced by stirring, incompletely dissolved trace impurities, and locally concentrated agglomerates, resulting in a homogeneous aqueous phase distribution of the polymer scale-inhibiting segments and the boron-containing polyhydroxy co-dispersant in the final aqueous solution.

[0022] When this scale inhibitor is added to high-hardness, silica-containing industrial reclaimed water, calcium ions in the water preferentially form primary inorganic crystal nuclei with carbonate, sulfate, and silicate species, and also coordinate with carboxylate scale inhibition sites. In this environment, simple carboxylate-type scale inhibitors are easily coordinated by multiple calcium ions, and polymer chains may adsorb between silicate species and calcium scale nuclei through calcium ion bridging, transforming the scale inhibitor from a component of dispersed crystal nuclei into part of a composite deposition. In this scheme, sulfonate segments provide a dispersion framework that is insensitive to calcium ions, maintaining the water solubility and charge repulsion of the polymer chains even at high calcium ion concentrations. Sodium polyepoxysuccinate and sodium polyaspartate provide adsorption sites for calcium scale nuclei, covering the surface of the nuclei and hindering the continued orderly growth of the crystals. Gluconate and borate species participate in the reversible complexation and hydration regulation around calcium ions and silica species, reducing the concentration of calcium ions at carboxylate polymer sites during the initial addition phase. Polyethylene glycol segments form a hydration shield around silica species, colloidal silica, and fine scale crystals, reducing the tendency for particles to aggregate tightly through hydrogen bonds, van der Waals interactions, and calcium bridging.

[0023] During the concentration of recycled water, silicic acid species undergo condensation, gradually forming polysilicic acid and colloidal silica. The colloidal silica surface possesses silanol groups, enabling interfacial adsorption with calcium ions, carboxylate groups, and inorganic crystal nuclei. When calcium carbonate or calcium sulfate nuclei coexist with polysilicic acid, calcium ions can form bridges between negatively charged surfaces, leading to the entrainment deposition of silicic acid species, calcium scale nuclei, and organic polymers. Once this entrainment deposition continues to accumulate on membrane surfaces, heat exchange surfaces, or pipe walls, the scale pores are filled with silicic acid gel and microcrystals, gradually densifying the deposit layer. In this solution, the sulfonic acid-containing copolymer weakens the proximity between crystal nuclei through negative charge repulsion and steric hindrance; polyethylene glycol weakens the condensation contact between silanol groups through a hydration layer; and gluconate and borate species influence the local coordination environment of silicic acid species and calcium ions through reversible complexation, making it difficult for silicic acid species to act as a cementing phase to compact and connect calcium scale nuclei. After polycarboxylic acid segments are adsorbed onto the surface of the crystal nucleus, the crystal shape and surface charge change, making it easier for the deposited particles to remain in a suspended and dispersed state, rather than continuously accumulating into a dense composite scale layer at the interface.

[0024] The inventive aspect of this solution lies in organizing the phosphorus-free polycarboxylate scale inhibitor segment, the calcium sulfonate-resistant dispersion segment, the boron-containing polyhydroxyl co-dispersion system, and the polyethylene glycol hydration segment into the same aqueous agent in a manner that first forms a polymer base liquid, then a boron-containing polyhydroxyl co-dispersion liquid, and subsequently, a composite mixture. The polymer base liquid ensures that the main scale inhibitor segment has already formed a stable dispersion state before being added to the co-dispersion system; the boron-containing polyhydroxyl co-dispersion liquid forms a reversible complexation and hydration environment through gluconate, borate species, and polyethylene glycol; after the two phases are combined, the carboxylate adsorption, sulfonate dispersion, polyhydroxyl complexation, and ether oxygen hydration correspond to the calcium scale nuclei, silica species, and calcium-silica composite deposition interface, respectively. Thus, the scale inhibitor does not rely on the single polycarboxylate component to consume and complex calcium ions, but rather reduces the risk of premature entrainment and deposition of effective action sites by calcium ions and silica species through the dispersion sequence and interfacial division of labor of the functional segments in the aqueous phase, and inhibits the transformation of calcium-silica composite scale from dispersed particles to a dense deposition layer.

[0025] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention uses a phosphorus-free polycarboxylic acid scale inhibitor, a sulfonic acid-containing dispersing component, a boron-containing polyhydroxyl co-dispersing component, and polyethylene glycol to jointly constitute a water treatment scale inhibitor system. It does not introduce organic phosphonates and inorganic phosphates, thus reducing the impact of the agent on the total phosphorus load of the water body after application. It is suitable as an environmentally friendly scale inhibitor and dispersant in water pollution control processes. During the preparation process, a polymer base liquid is first formed, followed by the formation of a boron-containing polyhydroxyl co-dispersing liquid, which is then compounded. This results in a more uniform distribution of the main scale inhibitory chain segment, calcium-resistant dispersing chain segment, polyhydroxyl complexing component, and hydration chain segment in the aqueous phase, reducing the premature consumption of polycarboxylic acid activity sites by calcium ions and silicic acid species in high-hardness silica-containing water systems. This scale inhibitor can suppress the continued orderly growth of calcium carbonate and calcium sulfate crystal nuclei and weaken the entrainment deposition between silica species, calcium scale nuclei and organic dispersed components, making it difficult for silica-calcium composite scale to form a dense deposition layer. This reduces the risk of scaling on membrane surfaces, heat exchange surfaces and pipelines, and maintains the continuous operational stability of industrial wastewater reuse, circulating water and reverse osmosis concentration and emission reduction systems. Attached Figure Description

[0026] Figure 1 The flowchart illustrates the preparation method provided by this invention. Detailed Implementation

[0027] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0028] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0029] In the following examples, unless otherwise stated, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is the AA / AMPS water treatment grade product sold by Shandong Taihe Technology Co., Ltd.; the polyepoxysuccinate sodium is the PESA water treatment grade product sold by Shandong Taihe Technology Co., Ltd.; the polyaspartic acid sodium is the PASP product sold by Shandong Yinuo Water Treatment Co., Ltd.; and the polyethylene glycol is the PEG series product sold by Jiangsu Dena Chemical Group Co., Ltd.

[0030] Example 1

[0031] This embodiment provides a method for preparing a highly efficient and environmentally friendly scale inhibitor, such as... Figure 1 As shown, it includes the following steps: S1, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is mixed with water, and then sodium polyepoxysuccinate and sodium polyaspartate are added. The mixture is stirred at 25°C for 90 min to obtain a polymer base liquid. The mass ratio of sodium polyepoxysuccinate, sodium polyaspartate, and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, based on the effective component mass, is 18:16:27, and the mass ratio of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer to water is 27:95. The limiting viscosity of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 0.055 dL / g, the relative molecular mass of sodium polyepoxysuccinate is 1500, and the relative molecular mass of sodium polyaspartate is 3000. S2, sodium gluconate and sodium tetraborate are added to water and stirred to dissolve. Then polyethylene glycol is added and stirring is continued. The mixture is stirred for 40 minutes at pH 8.4 and temperature 35℃ to obtain a boron-containing polyhydroxy dispersion. The mass ratio of sodium gluconate, sodium tetraborate and polyethylene glycol is 12:2.6:3 based on the mass of the effective components. Sodium tetraborate is calculated as anhydrous sodium tetraborate, and polyethylene glycol is PEG-300. The mass ratio of sodium gluconate to water is 12:50. S3, the boron-containing polyhydroxy co-dispersant liquid is added to the polymer base liquid by dropwise addition for 50 min, the temperature is 40 °C during the dropwise addition, and stirring is continued for 60 min after the dropwise addition is completed to obtain the composite scale inhibitor liquid; S4. Adjust the solid content of the composite scale inhibitor to 32 wt.% and the pH to 8.6. After standing for 1.5 hours to remove bubbles, filter it through a 100-mesh sieve to obtain a high-efficiency and environmentally friendly scale inhibitor.

[0032] Example 2

[0033] This embodiment provides a method for preparing a highly efficient and environmentally friendly scale inhibitor, including the following steps: S1, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is mixed with water, and then sodium polyepoxysuccinate and sodium polyaspartate are added. The mixture is stirred at 35°C for 60 min to obtain a polymer base liquid. The mass ratio of sodium polyepoxysuccinate, sodium polyaspartate, and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, based on the effective component mass, is 22:10:32, and the mass ratio of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer to water is 32:110. The limiting viscosity of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 0.085 dL / g, the relative molecular mass of sodium polyepoxysuccinate is 800, and the relative molecular mass of sodium polyaspartate is 1000. S2, sodium gluconate and sodium tetraborate are added to water and stirred to dissolve. Then polyethylene glycol is added and stirring is continued. The mixture is stirred for 60 minutes at pH 8.0 and temperature 40℃ to obtain a boron-containing polyhydroxy dispersion. The mass ratio of sodium gluconate, sodium tetraborate and polyethylene glycol is 15:0.8:6.2 based on the mass of the effective components. Sodium tetraborate is calculated as anhydrous sodium tetraborate, polyethylene glycol is PEG-400, and the mass ratio of sodium gluconate to water is 15:80. S3, the boron-containing polyhydroxy auxiliary dispersion is added to the polymer base liquid by dropwise addition for 20 min, the temperature is 25 °C during the dropwise addition, and stirring is continued for 90 min after the dropwise addition is completed to obtain the composite scale inhibitor; S4. Adjust the solid content of the composite scale inhibitor to 40 wt.% and the pH to 7.8. After standing for 0.5 hours to remove bubbles, filter it through a 120-mesh sieve to obtain a high-efficiency and environmentally friendly scale inhibitor.

[0034] Example 3

[0035] This embodiment provides a method for preparing a highly efficient and environmentally friendly scale inhibitor, including the following steps: S1, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is mixed with water, and then sodium polyepoxysuccinate and sodium polyaspartate are added. The mixture is stirred at 45°C for 30 min to obtain a polymer base liquid. The mass ratio of sodium polyepoxysuccinate, sodium polyaspartate, and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, based on the effective component mass, is 30:14:18, and the mass ratio of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer to water is 18:50. The limiting viscosity of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 0.100 dL / g, the relative molecular mass of sodium polyepoxysuccinate is 400, and the relative molecular mass of sodium polyaspartate is 5000. S2, sodium gluconate and sodium tetraborate are added to water and stirred to dissolve. Then polyethylene glycol is added and stirring is continued. The mixture is stirred for 20 minutes at pH 9.0 and temperature 25℃ to obtain a boron-containing polyhydroxy dispersion. The mass ratio of sodium gluconate, sodium tetraborate and polyethylene glycol is 18:1.7:4.8 based on the mass of the effective components. Sodium tetraborate is calculated as anhydrous sodium tetraborate, polyethylene glycol is PEG-600, and the mass ratio of sodium gluconate to water is 18:25. S3, the boron-containing polyhydroxy auxiliary dispersion is added to the polymer base liquid by dropwise addition for 60 min, the temperature is 45℃ during the dropwise addition, and stirring is continued for 30 min after the dropwise addition is completed to obtain the composite scale inhibitor; S4. Adjust the solid content of the composite scale inhibitor to 25 wt.% and the pH to 9.0. After standing for 2 hours to remove bubbles, filter it through an 80-mesh sieve to obtain a high-efficiency and environmentally friendly scale inhibitor.

[0036] Example 4

[0037] This embodiment provides a method for preparing a highly efficient and environmentally friendly scale inhibitor, including the following steps: S1, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is mixed with water, and then sodium polyepoxysuccinate and sodium polyaspartate are added. The mixture is stirred at 40°C for 75 min to obtain a polymer base liquid. The mass ratio of sodium polyepoxysuccinate, sodium polyaspartate, and acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 25:20:23, and the mass ratio of acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer to water is 23:70. The limiting viscosity of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is 0.070 dL / g, the relative molecular mass of sodium polyepoxysuccinate is 1100, and the relative molecular mass of sodium polyaspartate is 4000. S2, sodium gluconate and sodium tetraborate are added to water and stirred to dissolve. Then polyethylene glycol is added and stirring is continued. The mixture is stirred for 50 minutes at pH 8.7 and temperature 30℃ to obtain a boron-containing polyhydroxy dispersion. The mass ratio of sodium gluconate, sodium tetraborate and polyethylene glycol is 8:3.5:8 based on the mass of the effective components. Sodium tetraborate is calculated as anhydrous sodium tetraborate, polyethylene glycol is PEG-800, and the mass ratio of sodium gluconate to water is 8:35. S3, the boron-containing polyhydroxy auxiliary dispersion is added to the polymer base liquid by dropwise addition for 35 min, the temperature is 35 °C during the dropwise addition, and stirring is continued for 45 min after the dropwise addition is completed to obtain the composite scale inhibitor; S4. Adjust the solid content of the composite scale inhibitor to 36 wt.% and the pH to 8.3. After standing for 1 hour to remove bubbles, filter it through a 100-mesh sieve to obtain a high-efficiency and environmentally friendly scale inhibitor.

[0038] Comparative Example 1 This comparative example provides a method for preparing a highly efficient and environmentally friendly scale inhibitor. The difference between this method and Example 2 is that sodium tetraborate is not added in S2, while other process parameters and operating conditions are exactly the same as in Example 2.

[0039] Comparative Example 2 This comparative example provides a method for preparing a highly efficient and environmentally friendly scale inhibitor. The difference between this method and Example 2 is that sodium gluconate is not added in S2, while other process parameters and operating conditions are exactly the same as in Example 2.

[0040] Comparative Example 3 This comparative example provides a method for preparing a highly efficient and environmentally friendly scale inhibitor. The difference between this method and Example 2 is that polyethylene glycol is not added in S2, while other process parameters and operating conditions are exactly the same as in Example 2.

[0041] Comparative Example 4 This comparative example provides a method for preparing a highly efficient and environmentally friendly scale inhibitor. The difference between this method and Example 2 is that acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is not added in S1, while other process parameters and operating conditions are exactly the same as in Example 2.

[0042] Comparative Example 5 This comparative example provides a method for preparing a highly efficient and environmentally friendly scale inhibitor. The difference between this method and Example 2 is that, instead of preparing the polymer base liquid and the boron-containing polyhydroxyl co-dispersant liquid separately, the method involves mixing and stirring the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, sodium polyepoxysuccinate, sodium polyaspartate, sodium gluconate, sodium tetraborate, polyethylene glycol, and water in one step, adjusting the solid content and pH, and then allowing it to stand for degassing and filtration to obtain the highly efficient and environmentally friendly scale inhibitor. The amount of each raw material, the solid content, and the pH are exactly the same as in Example 2.

[0043] Performance testing: The scale inhibitors prepared in the examples and comparative examples were diluted with deionized water to prepare sample dilutions with an active ingredient concentration of 1.00 g / L. In all tests, the dosage of scale inhibitor in the dosing group was 10 mg / L based on the active ingredient, while no scale inhibitor was added to the blank group. Each sample was tested in parallel three times, and the average value of the results was taken. The results are shown in Table 1.

[0044] Calcium carbonate scale inhibition rate test: Add calcium chloride aqueous solution, sodium bicarbonate aqueous solution and deionized water to a 500mL stoppered bottle to prepare a test water sample, making the final volume of the test water sample 500mL, and ensuring that the calcium content in the test water sample is within acceptable limits. 2+ Concentration of 400 mg / L, HCO3 - The concentration was 1464 mg / L. 5.00 mL of sample diluent was added to the dosing group, and 5.00 mL of deionized water was added to the blank group to adjust the pH of the test water sample to 8.8. The stoppered bottle was incubated at 80℃ for 10 h, then cooled to 25℃ and filtered through a 0.45 μm filter membrane. 25.00 mL of the filtrate was taken, and sodium hydroxide solution was added to adjust to alkaline conditions. After adding calcium indicator, the solution was titrated with 0.01 mol / L EDTA standard solution to determine the Ca content in the filtrate. 2+ Concentration. The scale inhibition rate of calcium carbonate is calculated using the following formula: Calcium carbonate scale inhibition rate / % = (C1-C0) / (C2-C0)×100%.

[0045] In the formula, C1 represents the Ca in the filtrate after heat preservation and filtration of the dosing group.2+ Concentration, in mg / L; C0 represents the Ca in the filtrate after heat preservation and filtration in the blank group. 2+ Concentration, in mg / L; C2 is the Ca concentration in the water sample before heat preservation. 2+ Concentration, in mg / L.

[0046] Calcium sulfate scale inhibition rate test: Add calcium chloride aqueous solution, sodium sulfate aqueous solution and deionized water to a 500mL stoppered bottle to prepare a test water sample, making the final volume of the test water sample 500mL, and ensuring that the Ca content in the test water sample is within acceptable limits. 2+ Concentration of 1200 mg / L, SO4 2- The concentration was 3000 mg / L. 5.00 mL of sample diluent was added to the dosing group, and 5.00 mL of deionized water was added to the blank group to adjust the pH of the test water sample to 7.5. The stoppered bottle was incubated at 70℃ for 8 hours, and after incubation, cooled to 25℃ and filtered through a 0.45 μm filter membrane. 25.00 mL of the filtrate was taken, and sodium hydroxide solution was added to adjust to alkaline conditions. After adding calcium indicator, the solution was titrated with 0.01 mol / L EDTA standard solution to determine the Ca content in the filtrate. 2+ Concentration. The scale inhibition rate of calcium sulfate is calculated using the following formula: Calcium sulfate scale inhibition rate / % = (C3-C4) / (C5-C4)×100%.

[0047] In the formula, C3 represents the Ca in the filtrate after heat preservation and filtration of the dosing group. 2+ Concentration, in mg / L; C4 represents the Ca concentration in the filtrate after incubation and filtration in the blank group. 2+ Concentration, in mg / L; C5 represents the Ca concentration in the water sample before heat preservation. 2+ Concentration, in mg / L.

[0048] Test for inhibition rate of silica-calcium composite scale: Add calcium chloride aqueous solution, sodium bicarbonate aqueous solution, sodium sulfate aqueous solution, sodium metasilicate aqueous solution, and deionized water to a 500mL stoppered bottle to prepare a test water sample, making the final volume of the test water sample 500mL, and ensuring that the Ca content in the test water sample is within acceptable limits. 2+ Concentration of 500 mg / L, HCO3 - Concentration of 1500 mg / L, SO4 2-The concentration of soluble silicon (SiO2) was 1000 mg / L, and the concentration was 80 mg / L. 5.00 mL of sample diluent was added to the dosing group, and 5.00 mL of deionized water was added to the blank group to adjust the pH of the test water sample to 8.8. The stoppered bottle was incubated at 60℃ for 24 h, and then cooled to 25℃. All test water samples in the bottle were filtered through a pre-weighed 0.45 μm filter membrane, and the inner wall of the stoppered bottle and the filter residue were rinsed with 20 mL of deionized water. The filtered filter membrane and filter residue were dried at 105℃ for 2 h, cooled to 25℃, and weighed to calculate the mass of the deposit. The inhibition rate of the silicon-calcium composite scale was calculated using the following formula: The rate of inhibition of silicon-calcium composite scale is calculated as follows: (m0-m1) / m0 × 100%.

[0049] In the formula, m0 is the mass of sediment obtained from the blank group, in mg; m1 is the mass of sediment obtained from the drug-treated group, in mg.

[0050] Test on the inhibition rate of calcium silicate composite scale after repeated replenishment: First, prepare calcium chloride stock solutions, sodium bicarbonate stock solutions, and sodium metasilicate stock solutions respectively. Among them, the calcium chloride stock solution contains Ca... 2+ The concentration of HCO3 in sodium bicarbonate stock solution is 20000 mg / L. - The concentration was 61,000 mg / L, and the concentration of soluble silicon in the sodium metasilicate stock solution, calculated as SiO2, was 5,000 mg / L.

[0051] Add calcium chloride aqueous solution, sodium bicarbonate aqueous solution, sodium sulfate aqueous solution, sodium metasilicate aqueous solution, and deionized water to a 1000mL stoppered bottle to prepare an initial test water sample. The volume of the initial test water sample should be 500mL, and the initial test water sample should contain Ca... 2+ Concentration of 400 mg / L, HCO3 - Concentration of 1220 mg / L, SO4 2- The concentration of soluble silicon (calculated as SiO2) was 800 mg / L. 5.00 mL of sample diluent was added to the dosing group, and 5.00 mL of deionized water was added to the blank group to adjust the initial pH of the test water sample to 8.8.

[0052] The stoppered bottle was kept at 60℃, and replenishment was performed at 6h, 12h, and 18h. Each replenishment involved adding 2.00mL of calcium chloride stock solution, 2.00mL of sodium bicarbonate stock solution, and 2.00mL of sodium metasilicate stock solution, for a total replenishment volume of 6.00mL. Based on an initial test water sample volume of 500mL, each replenishment resulted in a decrease in Ca2+ concentration in the system. 2+ Increase by 80 mg / L, HCO3 -Increase the concentration of scale inhibitor by 244 mg / L and the concentration of soluble silica (calculated as SiO2) by 20 mg / L. After each addition, adjust the pH to 8.8 using sodium hydroxide or hydrochloric acid solution. The same addition and adjustment procedures were used for both the control group and the treated group. The total incubation time was 24 hours, during which no further scale inhibitor was added.

[0053] After the heat preservation period, cool to 25°C and record the final liquid volume. Filter all test water samples in the bottle using a pre-weighed 0.45μm filter membrane, and rinse the inner wall of the stoppered bottle and the filter residue with 20mL of deionized water. Dry the filtered membrane and residue at 105°C for 2 hours, cool to 25°C, weigh, and calculate the sediment mass. The inhibition rate of the silica-calcium composite scale after repeated replenishment is calculated using the following formula: After repeated replenishment, the inhibition rate of silicon-calcium composite scale is calculated as follows: (m2-m3) / m2×100%.

[0054] In the formula, m2 is the mass of sediment obtained after repeated replenishment in the blank group, in mg; m3 is the mass of sediment obtained after repeated replenishment in the drug-treated group, in mg.

[0055] Table 1. Test results of high-efficiency and environmentally friendly scale inhibitors in Examples 1-4 and Comparative Examples 1-5

[0056] As shown in Table 1, compared with Example 2, the calcium carbonate scale inhibition rate, calcium sulfate scale inhibition rate, calcium silicate composite scale inhibition rate, and calcium silicate composite scale inhibition rate after repeated replenishment of Comparative Examples 1, 2, 3, 4, and 5 were all reduced.

[0057] This is because, in Comparative Example 1, without the addition of sodium tetraborate, sodium gluconate and polyethylene glycol still provide complexing and hydration dispersion effects, but the regulatory effect of boron-containing components on the polyhydroxy co-dispersion system is reduced. The proportion of sodium gluconate participating in calcium ion complexation in a free state increases, and the degree to which the effective action sites of the scale inhibitor are prematurely consumed by calcium ions and silica species increases. Therefore, the scale inhibition rate of the calcium-silica composite scale and the scale inhibition rate after repeated replenishment decrease. In Comparative Example 2, without the addition of sodium gluconate, the number of polyhydroxy carboxylate structures in the system decreases. Sodium tetraborate is less likely to form a boron-containing polyhydroxy co-dispersion environment with the polyhydroxy carboxylate, reducing the complexing regulation effect on calcium ions and silica species. The proportion of polycarboxylate segments occupied by calcium ions and entrained into the composite deposition layer increases, thus reducing various scale inhibition and dispersion performances.

[0058] In Comparative Example 3, without the addition of polyethylene glycol, the hydration shielding effect of the ether oxygen segments in the system was reduced, the contact aggregation degree between silicic acid species, colloidal silica, and fine calcium scale nuclei increased, and the densification trend of the silicon-calcium composite scale deposit layer increased. Therefore, the silicon-calcium composite scale inhibition rate and the silicon-calcium composite scale inhibition rate after repeated addition were reduced. In Comparative Example 4, without the addition of acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, the number of calcium sulfonate-resistant dispersion segments in the system was reduced, the proportion of carboxylate sites of polyepoxysuccinate and polyaspartic acid sodium salt consumed in the high calcium environment increased, and the stability of the dispersion framework decreased. Therefore, the calcium carbonate scale inhibition rate, calcium sulfate scale inhibition rate, silicon-calcium composite scale inhibition rate, and silicon-calcium composite scale inhibition rate after repeated addition were all reduced.

[0059] Comparative Example 5 used a one-time mixing method, without forming a polymer base liquid and a boron-containing polyhydroxy auxiliary dispersion liquid separately. The dispersion order of polymer segments, polyhydroxy components, boron-containing components and polyethylene glycol in the aqueous phase was changed, the local concentration fluctuation increased, and the regulating effect of the auxiliary dispersion component on the polymer scale inhibition segments was reduced. Therefore, the scale inhibition and dispersion performance of each component was reduced.

[0060] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A highly efficient and environmentally friendly scale inhibitor, characterized in that, The scale inhibitor is a phosphorus-free water treatment scale inhibitor, which, by mass of effective ingredients, includes sodium polyepoxysuccinate, sodium polyaspartate, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, sodium gluconate, sodium tetraborate and polyethylene glycol, and the mass ratio of the above components is (18-30):(10-20):(18-32):(8-18):(0.8-3.5):(3-8), wherein the sodium tetraborate is calculated as anhydrous sodium tetraborate.

2. The high-efficiency and environmentally friendly scale inhibitor according to claim 1, characterized in that, The scale inhibitor does not contain organic phosphonates or inorganic phosphates.

3. The high-efficiency and environmentally friendly scale inhibitor according to claim 1, characterized in that, The sodium tetraborate is anhydrous sodium tetraborate, sodium tetraborate pentahydrate, or sodium tetraborate decahydrate.

4. A method for preparing a high-efficiency and environmentally friendly scale inhibitor as described in any one of claims 1-3, characterized in that, Includes the following steps: S1, mix acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, sodium polyepoxysuccinate, sodium polyaspartate and water, and stir to obtain polymer base liquid; S2, Sodium gluconate, sodium tetraborate, polyethylene glycol and water are mixed and stirred under alkaline conditions to obtain a boron-containing polyhydroxyl co-dispersant; S3, add the boron-containing polyhydroxyl co-dispersant to the polymer base liquid, stir and mix to obtain a composite scale inhibitor; S4. Adjust the solid content and pH of the composite scale inhibitor, and after standing to defoam and filter, obtain a high-efficiency and environmentally friendly scale inhibitor.

5. The method for preparing a high-efficiency and environmentally friendly scale inhibitor according to claim 4, characterized in that, In S1, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is first mixed with water, and then sodium polyepoxysuccinate and sodium polyaspartate are added. The stirring temperature is 25-45℃ and the stirring time is 30-90min. The mass ratio of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer to water is (18-32):(50-110).

6. The method for preparing a high-efficiency and environmentally friendly scale inhibitor according to claim 4, characterized in that, In S2, the alkaline conditions are pH 8.0-9.0, the stirring temperature is 25-40℃, and the stirring time is 20-60 min.

7. The method for preparing a high-efficiency and environmentally friendly scale inhibitor according to claim 4, characterized in that, In S2, sodium gluconate and sodium tetraborate are first added to water and stirred to dissolve, then polyethylene glycol is added and stirring is continued; the mass ratio of sodium gluconate to water is (8-18):(25-80).

8. The method for preparing a high-efficiency and environmentally friendly scale inhibitor according to claim 4, characterized in that, In S3, the boron-containing polyhydroxy dispersant is added to the polymer base liquid by dropwise addition for 20-60 minutes, and the temperature during the dropwise addition is 25-45℃.

9. The method for preparing a high-efficiency and environmentally friendly scale inhibitor according to claim 4, characterized in that, In step S3, after the boron-containing polyhydroxy dispersant is added, continue stirring for 30-90 minutes.

10. The method for preparing a high-efficiency and environmentally friendly scale inhibitor according to claim 4, characterized in that, In S4, the settling and degassing time is 0.5-2 hours, and filtration is performed using an 80-120 mesh sieve.

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