Composite corrosion and scale inhibition water treatment agent and preparation method thereof

Abstract

The application relates to a composite type corrosion and scale inhibition water treatment agent, which is obtained by in-situ copolymerization of phosphono carboxylic acid copolymer after modification of nitrogen-doped carbon quantum dots on the surface of attapulgite as a carrier. The application has the beneficial effects that: the attapulgite is used as the carrier, can be used as a grafting bridge to load the carbon quantum dots on the surface and in-situ generate the phosphono carboxylic acid copolymer, and has a synergistic effect; the nitrogen-doped carbon quantum dots have rich amino, carboxyl and hydroxyl functional groups on the surface, make it difficult for calcium carbonate microcrystals to gather or interfere with the normal growth of the crystals to inhibit scale crystal generation, have high stability, are coated with zinc ions, improve the antibacterial property of the material, are modified on the surface of the attapulgite, have excellent adsorption performance, and can effectively remove organic matters, heavy metals and the like in water; the phosphono carboxylic acid copolymer is in-situ generated on the surface of the attapulgite, has a good compounding effect, has a good effect on corrosion inhibition, and has good corrosion inhibition performance.

Description

Technical Field

[0001] This invention relates to the field of water treatment agent preparation technology, specifically to a composite corrosion and scale inhibitor water treatment agent and its preparation method. Background Technology

[0002] Water treatment agents are core materials for solving industrial water pollution and improving water recycling rates. They come in a wide variety, forming flocculants, flocculants, corrosion inhibitors, bactericides, deodorizers, decolorizing agents, cleaning agents, and more, based on different mechanisms of action. Different water treatment agents have unique advantages but also limitations. Therefore, in practical applications, it is often necessary to use composite formulations of water treatment agents tailored to different industrial wastewater to achieve maximum treatment efficiency. In the inventor's region, in addition to wastewater from industrial production containing heavy metals, high concentrations of phenols, and recalcitrant organic matter, the water itself is characterized by high hardness and high chloride ion content. Recycling requires the addition of corrosion-inhibiting and scale-inhibiting agents. Existing scale inhibitors use phosphorus-containing formulations, which easily lead to eutrophication of water bodies, and organophosphate agents have poor biodegradability, easily causing secondary pollution to the environment. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention designs a low-phosphorus scale inhibitor based on nanomaterial composite modification, suitable for industrial circulating cooling water systems operating under high hardness and high chloride ion conditions.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A composite corrosion and scale inhibitor water treatment agent is obtained by in-situ copolymerization of attapulgite as a carrier, modified with nitrogen-doped carbon quantum dots, to form a phosphonocarboxylic acid copolymer; wherein,

[0006] The nitrogen-doped carbon quantum dots are prepared as follows: glucose, itaconic acid, and benzotriazole are added to a 50% ethanol aqueous solution and stirred evenly to obtain mixture A. ZnCl2·H2O and ethylenediamine are added to deionized water and stirred evenly to obtain mixture B. Mixture A is heated and stirred. Mixture B is added to mixture A while stirring. Then, the mixture is transferred to a high-pressure reactor for hydrothermal reaction. After cooling, it is dialyzed and dried to obtain the final product.

[0007] The monomers of the phosphonocarboxylic acid copolymer include maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide, in a molar ratio of 5~10:2~4:1.

[0008] Furthermore, in the preparation process of the nitrogen-doped carbon quantum dots, the mass ratio of glucose, itaconic acid, and benzotriazole is 10:1~2:2~5; and the mass ratio of ZnCl2·H2O and ethylenediamine is 1~1.5:1.

[0009] Furthermore, in the preparation process of the nitrogen-doped carbon quantum dots, the hydrothermal reaction temperature is 180~200℃ and the reaction time is 8~12h.

[0010] Furthermore, the N-substituted hydroxyethylidene diphosphonate-maleimide has the following structural formula: It is prepared by reacting maleimide with hydroxyethylidene diphosphonic acid in K2CO3 / DMF under DCC / DMAP-assisted esterification.

[0011] This invention further provides a method for preparing a composite corrosion and scale inhibitor water treatment agent, comprising the following steps:

[0012] S1. Add 3-aminopropyltriethoxysilane and anhydrous ethanol to a reaction flask to obtain a mixed solution. Adjust the pH to acidic. Disperse the activated attapulgite in the mixed solution by ultrasound. Heat to 60°C and react with ultrasound for 3 hours. Filter. Wash the product three times with water and ethanol. Dry to obtain modified attapulgite.

[0013] S2. The modified attapulgite and nitrogen-doped carbon quantum dots are evenly dispersed in deionized water. Nitrogen gas is introduced into the aqueous solution of the modified attapulgite to remove air, and the temperature is raised to 50~60℃. Then, the aqueous solution of nitrogen-doped carbon quantum dots is added while stirring, and the mixture is sonicated for 30 min.

[0014] S3. Add the initiator to the reaction system in step S2 and stir until homogeneous. Heat to 60-70°C and maintain a nitrogen atmosphere. Mix maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide in the molar ratio and add dropwise to the reaction system. After the addition is complete, heat to 80-90°C and react for 4-6 hours. After cooling, filter and dry to obtain the final product.

[0015] Furthermore, the activation process of the activated attapulgite soil is as follows:

[0016] After grinding and sieving the natural attapulgite, the attapulgite was soaked in a 1M sodium hydroxide solution for 2 hours at a solid-liquid ratio of 1:10 g / mL. After filtration and washing with water, it was soaked in a 3M hydrochloric acid solution, heated in an 80℃ water bath for 4 hours, cooled and filtered, washed with water until neutral, and dried.

[0017] Furthermore, the mass ratio of the modified attapulgite to nitrogen-doped carbon quantum dots is 1:0.3~0.8.

[0018] Furthermore, the initiator is potassium persulfate, ammonium persulfate, or benzoyl peroxide.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. This invention uses attapulgite as a carrier. The nanotube structure can limit the formation of scale crystals. In addition, after activation, its specific surface area increases and the surface has abundant loading sites. It can be used as a grafting bridge to load carbon quantum dots on its surface and generate phosphonocarboxylic acid copolymers in situ, which plays a synergistic role.

[0021] 2. The surface of nitrogen-doped carbon quantum dots is rich in amino, carboxyl and hydroxyl functional groups, which makes it difficult for calcium carbonate microcrystals to aggregate or interfere with the normal growth of crystals, thereby inhibiting the formation of scale crystals and exhibiting high stability. At the same time, the zinc ions are coated, which improves the antibacterial properties of the material. When modified onto the surface of attapulgite, it has excellent adsorption performance and can effectively remove organic matter, heavy metals and other substances from water.

[0022] 3. Phosphonocarboxylic acid copolymers are generated in situ on the surface of attapulgite, resulting in good compounding effects. The copolymers contain abundant carboxyl, phosphono, amide, sulfonic acid, and heterocyclic structures. The phosphono groups are provided by N-substituted hydroxyethylidene diphosphonate-maleimide, forming a dense protective layer on the metal surface, which has a good effect on inhibiting corrosion and exhibits good corrosion inhibition properties. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0024] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Example 1: A composite corrosion and scale inhibitor water treatment agent

[0026] S1. Activation of attapulgite: Grind and crush natural attapulgite and sieve it. Soak the attapulgite in 1M sodium hydroxide solution for 2 hours at a solid-liquid ratio of 1:10 g / mL. After filtration and washing with water, soak it in 3M hydrochloric acid solution, heat it in a water bath at 80℃ for 4 hours, cool and filter it, wash it with water until neutral, and dry it.

[0027] Preparation of nitrogen-doped carbon quantum dots: 2 g glucose, 0.2 g itaconic acid, and 0.4 g benzotriazole were added to 10 ml of 50% ethanol aqueous solution and stirred until homogeneous to obtain mixture A. 0.2 g ZnCl2·H2O and 0.2 g ethylenediamine were added to 2 ml of deionized water and stirred until homogeneous to obtain mixture B. Mixture A was heated and stirred, and mixture B was added to mixture A while stirring. The mixture was then transferred to a high-pressure reactor and hydrothermally reacted at 180℃ for 8 h. After cooling, the mixture was dialyzed and dried to obtain the final product.

[0028] Obtaining the comonomer: Maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide were mixed in a molar ratio of 5:2:1, wherein the structural formula of N-substituted hydroxyethylidene diphosphonate-maleimide is: It is prepared by reacting maleimide with hydroxyethylidene diphosphonic acid in K2CO3 / DMF under DCC / DMAP-assisted esterification.

[0029] S2. Add 10g of 3-aminopropyltriethoxysilane and anhydrous ethanol to the reaction flask to obtain a mixed solution. Disperse 2g of activated attapulgite in the mixed solution by ultrasound. Heat to 60℃ and react with ultrasound assistance for 3 hours. Filter, wash the product three times with water and ethanol, and dry to obtain modified attapulgite.

[0030] S3. Disperse 1g of modified attapulgite and 0.3g of nitrogen-doped carbon quantum dots evenly in deionized water. Purge the modified attapulgite aqueous solution with nitrogen to remove air and heat to 50~60℃. Then, while stirring, add the nitrogen-doped carbon quantum dot aqueous solution and continue sonication for 30 min.

[0031] S4. Add potassium persulfate initiator to the above reaction system and stir until homogeneous. Heat to 60-70℃ and maintain a nitrogen atmosphere. Mix maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide in the molar ratio. Add 2g of the monomer mixture dropwise to the reaction system. After the addition is complete, heat to 80-90℃ and react for 4-6 hours. After cooling, filter and dry to obtain the final product.

[0032] Example 2: A composite corrosion and scale inhibitor water treatment agent

[0033] S1. Activation of attapulgite: Grind and crush natural attapulgite and sieve it. Soak the attapulgite in 1M sodium hydroxide solution for 2 hours at a solid-liquid ratio of 1:10 g / mL. After filtration and washing with water, soak it in 3M hydrochloric acid solution, heat it in a water bath at 80℃ for 4 hours, cool and filter it, wash it with water until neutral, and dry it.

[0034] Preparation of nitrogen-doped carbon quantum dots: 2.5 g glucose, 0.5 g itaconic acid, and 1.2 g benzotriazole were added to 10 ml of 50% ethanol aqueous solution and stirred until homogeneous to obtain mixture A. 0.5 g ZnCl2·H2O and 0.5 g ethylenediamine were added to 2 ml of deionized water and stirred until homogeneous to obtain mixture B. Mixture A was heated and stirred, and mixture B was added to mixture A while stirring. The mixture was then transferred to a high-pressure reactor and hydrothermally reacted at 180℃ for 8 h. After cooling, the mixture was dialyzed and dried to obtain the final product.

[0035] Obtaining the comonomer: Maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide were mixed in a molar ratio of 8:2:1, wherein the structural formula of N-substituted hydroxyethylidene diphosphonate-maleimide is: It is prepared by reacting maleimide with hydroxyethylidene diphosphonic acid in K2CO3 / DMF under DCC / DMAP-assisted esterification.

[0036] S2. Add 10g of 3-aminopropyltriethoxysilane and anhydrous ethanol to the reaction flask to obtain a mixed solution. Disperse 2g of activated attapulgite in the mixed solution by ultrasound. Heat to 60℃ and react with ultrasound assistance for 3 hours. Filter, wash the product three times with water and ethanol, and dry to obtain modified attapulgite.

[0037] S3. Disperse 1g of modified attapulgite and 0.5g of nitrogen-doped carbon quantum dots evenly in deionized water. Purge the modified attapulgite aqueous solution with nitrogen to remove air and heat to 50~60℃. Then, while stirring, add the nitrogen-doped carbon quantum dot aqueous solution and continue sonication for 30 min.

[0038] S4. Add potassium persulfate initiator to the above reaction system and stir until homogeneous. Heat to 60-70℃ and maintain a nitrogen atmosphere. Mix maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide in the molar ratio. Add 2g of the monomer mixture dropwise to the reaction system. After the addition is complete, heat to 80-90℃ and react for 4-6 hours. After cooling, filter and dry to obtain the final product.

[0039] Example 3: A composite corrosion and scale inhibitor water treatment agent

[0040] S1. Activation of attapulgite: Grind and crush natural attapulgite and sieve it. Soak the attapulgite in 1M sodium hydroxide solution for 2 hours at a solid-liquid ratio of 1:10 g / mL. After filtration and washing with water, soak it in 3M hydrochloric acid solution, heat it in a water bath at 80℃ for 4 hours, cool and filter it, wash it with water until neutral, and dry it.

[0041] Preparation of nitrogen-doped carbon quantum dots: 2.5 g glucose, 0.5 g itaconic acid, and 1.2 g benzotriazole were added to 10 ml of 50% ethanol aqueous solution and stirred until homogeneous to obtain mixture A. 0.5 g ZnCl2·H2O and 0.5 g ethylenediamine were added to 2 ml of deionized water and stirred until homogeneous to obtain mixture B. Mixture A was heated and stirred, and mixture B was added to mixture A while stirring. The mixture was then transferred to a high-pressure reactor and hydrothermally reacted at 180℃ for 8 h. After cooling, the mixture was dialyzed and dried to obtain the final product.

[0042] Obtaining the comonomer: Maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide were mixed in a molar ratio of 10:4:1, wherein the structural formula of N-substituted hydroxyethylidene diphosphonate-maleimide is: It is prepared by reacting maleimide with hydroxyethylidene diphosphonic acid in K2CO3 / DMF under DCC / DMAP-assisted esterification.

[0043] S2. Add 10g of 3-aminopropyltriethoxysilane and anhydrous ethanol to the reaction flask to obtain a mixed solution. Disperse 2g of activated attapulgite in the mixed solution by ultrasound. Heat to 60℃ and react with ultrasound assistance for 3 hours. Filter, wash the product three times with water and ethanol, and dry to obtain modified attapulgite.

[0044] S3. Disperse 1g of modified attapulgite and 0.8g of nitrogen-doped carbon quantum dots evenly in deionized water. Purge the modified attapulgite aqueous solution with nitrogen to remove air and heat to 50~60℃. Then, while stirring, add the nitrogen-doped carbon quantum dot aqueous solution and continue sonication for 30 min.

[0045] S4. Add potassium persulfate initiator to the above reaction system and stir until homogeneous. Heat to 60-70℃ and maintain a nitrogen atmosphere. Mix maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide in the molar ratio. Add 2g of the monomer mixture dropwise to the reaction system. After the addition is complete, heat to 80-90℃ and react for 4-6 hours. After cooling, filter and dry to obtain the final product.

[0046] Comparative Example 1:

[0047] Same as Example 1, except that the attapulgite clay was used directly without activation.

[0048] Comparative Example 2:

[0049] S1. Activation of attapulgite: Grind and crush natural attapulgite and sieve it. Soak the attapulgite in 1M sodium hydroxide solution for 2 hours at a solid-liquid ratio of 1:10 g / mL. After filtration and washing with water, soak it in 3M hydrochloric acid solution, heat it in a water bath at 80℃ for 4 hours, cool and filter it, wash it with water until neutral, and dry it.

[0050] Preparation of nitrogen-doped carbon quantum dots: 2 g glucose and 0.2 g itaconic acid were added to 10 ml of 50% ethanol aqueous solution and stirred evenly to obtain mixture A. 0.2 g ZnCl2·H2O and 0.2 g ethylenediamine were added to 2 ml of deionized water and stirred evenly to obtain mixture B. Mixture A was heated and stirred, and mixture B was added to mixture A while stirring. Then, the mixture was transferred to a high-pressure reactor and hydrothermally reacted at 180℃ for 8 h. After cooling, it was dialyzed and dried to obtain the final product.

[0051] Obtaining the comonomer: Maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide were mixed in a molar ratio of 5:2:1, wherein the structural formula of N-substituted hydroxyethylidene diphosphonate-maleimide is: It is prepared by reacting maleimide with hydroxyethylidene diphosphonic acid in K2CO3 / DMF under DCC / DMAP-assisted esterification.

[0052] The rest is the same as in Example 1.

[0053] Comparative Example 3:

[0054] S1. Activation of attapulgite: Grind and crush natural attapulgite and sieve it. Soak the attapulgite in 1M sodium hydroxide solution for 2 hours at a solid-liquid ratio of 1:10 g / mL. After filtration and washing with water, soak it in 3M hydrochloric acid solution, heat it in a water bath at 80℃ for 4 hours, cool and filter it, wash it with water until neutral, and dry it.

[0055] Preparation of nitrogen-doped carbon quantum dots: 2 g glucose, 0.2 g itaconic acid, and 0.4 g benzotriazole were added to 10 ml of 50% ethanol aqueous solution and stirred until homogeneous to obtain mixture A. 0.2 g ZnCl2·H2O and 0.2 g ethylenediamine were added to 2 ml of deionized water and stirred until homogeneous to obtain mixture B. Mixture A was heated and stirred, and mixture B was added to mixture A while stirring. The mixture was then transferred to a high-pressure reactor and hydrothermally reacted at 180℃ for 8 h. After cooling, the mixture was dialyzed and dried to obtain the final product.

[0056] Obtaining the comonomer: maleic acid, 2-acrylamide-2-methylpropanesulfonic acid and phosphorous acid were mixed in a molar ratio of 5:2:1.

[0057] The rest is the same as in Example 1.

[0058] Scale inhibition performance: The scale inhibition rate of the water treatment agent was tested according to the method specified in GB / T16632-2019;

[0059] Corrosion inhibition performance: The average corrosion rate of the water treatment agent (mm / a) was tested according to the method specified in GB / T18175-2000. Records are shown in Table 1.

[0060] Table 1

[0061]

[0062] As shown in Table 1, unactivated attapulgite clay, due to its numerous surface impurities and few functional groups, is less effective as a carrier for growing carbon quantum dots and in-situ polymerizing phosphonocarboxylic acid copolymers, resulting in poor scale inhibition and corrosion inhibition properties. Comparative Example 2, by omitting benzotriazole during carbon quantum dot preparation, significantly reduced nitrogen doping and thus exhibited poor scale inhibition performance. Comparative Example 3, using phosphorous acid as a chain transfer agent to prepare phosphonocarboxylic acid copolymers, showed a significantly increased number of phosphono groups compared to Example 1, which used a self-made N-substituted hydroxyethylidene diphosphonate-maleimide. The presence of heterocyclic structures in Example 1 significantly enhanced the adsorption performance of scale crystals, hindering their normal growth and inhibiting their precipitation. Therefore, the scale inhibition rate was significantly improved.

[0063] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A composite corrosion and scale inhibitor water treatment agent, characterized in that, It is obtained by in-situ copolymerization of activated and modified attapulgite as a carrier, followed by modification of its surface with nitrogen-doped carbon quantum dots to generate a phosphonocarboxylic acid copolymer; wherein, The nitrogen-doped carbon quantum dots are prepared as follows: glucose, itaconic acid, and benzotriazole are added to a 50% ethanol aqueous solution and stirred evenly to obtain mixture A. ZnCl2·H2O and ethylenediamine are added to deionized water and stirred evenly to obtain mixture B. Mixture A is heated and stirred. Mixture B is added to mixture A while stirring. Then, the mixture is transferred to a high-pressure reactor for hydrothermal reaction. After cooling, it is dialyzed and dried to obtain the final product. The monomers of the phosphonocarboxylic acid copolymer include: maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide, in a molar ratio of 5~10:2~4:

1. The N-substituted hydroxyethylidene diphosphonate-maleimide is prepared by reacting maleimide with hydroxyethylidene diphosphonic acid in K2CO3 / DMF under DCC / DMAP-assisted esterification.

2. The composite corrosion and scale inhibitor water treatment agent as described in claim 1, characterized in that, In the preparation process of the nitrogen-doped carbon quantum dots, the mass ratio of glucose, itaconic acid, and benzotriazole is 10:1~2:2~5; the mass ratio of ZnCl2·H2O and ethylenediamine is 1~1.5:

1.

3. The composite corrosion and scale inhibitor water treatment agent as described in claim 2, characterized in that, In the preparation process of the nitrogen-doped carbon quantum dots, the hydrothermal reaction temperature is 180~200℃ and the reaction time is 8~12h.

4. A method for preparing a composite corrosion and scale inhibitor water treatment agent as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Add 3-aminopropyltriethoxysilane and anhydrous ethanol to a reaction flask to obtain a mixed solution. Adjust the pH to acidic. Disperse the activated attapulgite in the mixed solution by ultrasound. Heat to 60°C and react with ultrasound for 3 hours. Filter. Wash the product three times with water and ethanol. Dry to obtain modified attapulgite. S2. The modified attapulgite and nitrogen-doped carbon quantum dots are evenly dispersed in deionized water. Nitrogen gas is introduced into the aqueous solution of the modified attapulgite to remove air, and the temperature is raised to 50~60℃. Then, the aqueous solution of nitrogen-doped carbon quantum dots is added while stirring, and the mixture is sonicated for 30 min. S3. Add the initiator to the reaction system in step S2 and stir until homogeneous. Heat to 60-70°C and maintain a nitrogen atmosphere. Mix maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, and N-substituted hydroxyethylidene diphosphonate-maleimide in the molar ratio and add dropwise to the reaction system. After the addition is complete, heat to 80-90°C and react for 4-6 hours. After cooling, filter and dry to obtain the final product.

5. The method as described in claim 4, characterized in that, The activation process of the activated attapulgite soil is as follows: After grinding and sieving the natural attapulgite, the attapulgite was soaked in a 1M sodium hydroxide solution for 2 hours at a solid-liquid ratio of 1:10 g / mL. After filtration and washing with water, it was soaked in a 3M hydrochloric acid solution, heated in an 80℃ water bath for 4 hours, cooled and filtered, washed with water until neutral, and dried.

6. The method as described in claim 4, characterized in that, The mass ratio of the modified attapulgite to nitrogen-doped carbon quantum dots is 1:0.3~0.

8.

7. The method as described in claim 4, characterized in that, The initiator is potassium persulfate or ammonium persulfate.

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