A scale inhibitor for high-concentration brine concentrated by a wastewater reuse membrane and a preparation method thereof

Abstract

A kind of wastewater reuse membrane concentrates high concentration brine scale inhibitor, by mass fraction, it is mainly prepared by the following raw materials: hydrolyzed polymaleic anhydride 20-35 parts, 2-acrylamide-2-methylpropyl phosphonic acid 12-25 parts, ammonium persulfate 5-8 parts, propylene-hydroxypropyl acrylate copolymer 10-25 parts, polyepoxysuccinic acid 15-25 parts, benzotriazole 5-15 parts and deionized water 30-50 parts.The scale inhibitor has excellent application effect and production value, creates indispensable guarantee for enterprise to delay pipeline and equipment pollution, prolongs cleaning cycle, ensures long-term stable operation of equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, in particular to a wastewater recycling membrane concentrated high-concentration brine scale inhibitor and a preparation method thereof. Background Art

[0002] At present, a large amount of brine is produced during the membrane concentration process of wastewater treatment. The main components of the brine are inorganic salts and heavy metals. It also contains a small amount of chemicals used in pretreatment, chlorination, dechlorination and desalination processes. The treatment of brine has become a key technology restricting the zero discharge of industrial wastewater in various industries.

[0003] Due to the diverse composition and sources of high-salinity brine, concentration and treatment are challenging. During the treatment of brine, due to its complex composition, it is easy to form difficult-to-treat scale in a short period of time. Therefore, it is necessary to add scale inhibitors during the treatment process to delay pipe and equipment clogging, extend cleaning cycles, and ensure long-term stable operation of the equipment.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The first object of the present invention is to provide a wastewater reuse membrane concentrated high-concentration brine scale inhibitor, which has a high scale inhibition rate, can effectively delay the fouling of pipelines and equipment, and extend the cleaning cycle.

[0006] The second object of the present invention is to provide a method for preparing a wastewater reuse membrane concentrated high-concentration brine scale inhibitor, which has simple operation, low reagent consumption, and mild operating conditions.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0008] The invention provides a wastewater reuse membrane concentrated high-concentration brine scale inhibitor, which is mainly prepared from the following raw materials, calculated by weight: 20-35 parts of hydrolyzed polymaleic anhydride, 12-25 parts of 2-acrylamide-2-methylpropylphosphonic acid, 5-8 parts of ammonium persulfate, 10-25 parts of propylene-hydroxypropyl acrylate copolymer, 15-25 parts of polyepoxysuccinic acid, 5-15 parts of benzotriazole and 30-50 parts of deionized water.

[0009] Preferably, as a further specific embodiment, it is mainly prepared from the following raw materials: 30-35 parts of hydrolyzed polymaleic anhydride, 16-25 parts of 2-acrylamide-2-methylpropylphosphonic acid, 7-8 parts of ammonium persulfate, 15-25 parts of propylene-hydroxypropyl acrylate copolymer, 20-25 parts of polyepoxysuccinic acid, 10-15 parts of benzotriazole and 35-50 parts of deionized water.

[0010] Preferably, as a further specific embodiment, it is mainly prepared from the following raw materials: 33 parts of hydrolyzed polymaleic anhydride, 19 parts of 2-acrylamide-2-methylpropylphosphonic acid, 8 parts of ammonium persulfate, 18 parts of propylene-hydroxypropyl acrylate copolymer, 24 parts of polyepoxysuccinic acid, 11 parts of benzotriazole and 40 parts of deionized water.

[0011] The hydrolyzed polymaleic anhydride added in the present invention is an organic fatty acid polymer with good stability, is easily soluble in water, and can produce a very good scale inhibition effect on carbonates and phosphates. The carboxyl groups in the hydrolyzed polymaleic anhydride molecules can form compounds with calcium, magnesium and other ions in water, and can cause lattice distortion, so that the precipitate is converted into loose water slag with good fluidity, so that the scale inhibitor will not clog the equipment after forming compounds with ions in water.

[0012] The 2-acrylamide-2-methylpropylphosphonic acid added in the present invention is a polyphosphonate scale inhibitor that can form complexes with metal ions in water. These complexes have low solubility and can prevent metal ions from depositing on the surfaces of pipes, equipment, etc. to form scale.

[0013] The present invention allows hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid to be compatible with each other, so that metal ions in water can better form a water-soluble complex. 2-acrylamide-2-methylpropylphosphonic acid can change the chemical balance in water, so that the balance between carbonate and phosphate in the water is more inclined to phosphate. Phosphate is one of the main components of scale, and phosphate has a low solubility. Therefore, the complex finally formed by the scale inhibitor will not clog equipment.

[0014] The present invention further adds benzotriazole, which is used in conjunction with the hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid in the scale inhibitor to enhance the scale inhibition effect of the scale inhibitor.

[0015] The sodium polyepoxysuccinate added in the present invention is a biodegradable green water treatment agent. Its molecules contain two functional groups, a carboxyl group and an ether group, which can produce a slow-release synergistic effect with hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid, so that the hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid in the scale inhibitor can form a more stable chelate with metal ions in water.

[0016] The present invention also provides a method for preparing the above-mentioned wastewater reuse membrane concentrated high-concentration brine scale inhibitor, comprising the following steps:

[0017] Add hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid, heat and stir;

[0018] Add ammonium persulfate to the mixture of hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid, then raise the temperature and continue the reaction for 3 hours;

[0019] After the temperature is allowed to stand at 20-25° C., propylene-hydroxypropyl acrylate copolymer, polyepoxysuccinic acid, benzotriazole and deionized water are sequentially added to the solution to which ammonium persulfate has been added, and the mixture is stirred.

[0020] Preferably, as a further specific embodiment, after adding hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid, the temperature is raised to 43-47° C. and stirring is continued for 30 minutes.

[0021] Preferably, as a further specific embodiment, sodium persulfate is added to the mixture of hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid three times with an interval of 60 minutes each time. After the addition, the temperature is raised to 58-62° C. and the temperature is maintained.

[0022] Preferably, as a further specific embodiment, propylene-hydroxypropyl acrylate copolymer, polyepoxysuccinic acid, benzotriazole, and deionized water are added in sequence, and then stirred for 30 minutes.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The scale inhibitor provided by the present invention can effectively form stable soluble chelates with various metal ions in highly concentrated brine, stabilize more metal ions in water, increase the solubility of metal salts, and inhibit the growth and deposition of scale.

[0025] (2) The scale inhibitor of the present invention has a good scale inhibition effect, which is better than the commonly used organic phosphoric acid, especially the scale inhibition effect is more significant in highly concentrated brine.

[0026] Various additional advantages and benefits will become apparent to those of ordinary skill in the art from a reading of the following detailed description of the preferred embodiment. DETAILED DESCRIPTION

[0027] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. However, those skilled in the art will understand that the embodiments described below are part of the embodiments of the present invention, not all of them, and are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] In order to more clearly illustrate the technical solutions of the present invention, specific embodiments are provided below for illustration.

[0029] Example 1

[0030] A wastewater reuse membrane concentrated high-concentration brine scale inhibitor, calculated by mass fraction, comprises 20 parts of hydrolyzed polymaleic anhydride, 12 parts of 2-acrylamide-2-methylpropylphosphonic acid, 5 parts of ammonium persulfate, 10 parts of propylene-hydroxypropyl acrylate copolymer, 15 parts of polyepoxysuccinic acid, 5 parts of benzotriazole, and 30 parts of deionized water.

[0031] (1) Add hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid into a reaction kettle, stir, heat to 45°C, and continue stirring for 30 minutes.

[0032] (2) Adding ammonium persulfate to the mixture of hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid three times with an interval of 60 minutes, raising the temperature to 60°C after each addition, maintaining the temperature, and continuing the reaction for 3 hours.

[0033] (3) After standing to 25°C, propylene-hydroxypropyl acrylate copolymer, sodium polyepoxysuccinate, benzotriazole and deionized water were added in sequence and stirred for 30 minutes.

[0034] Example 2

[0035] The specific preparation steps of the scale inhibitor are the same as those in Example 1, except that the components are adjusted by weight to 35 parts of hydrolyzed polymaleic anhydride, 25 parts of 2-acrylamide-2-methylpropylphosphonic acid, 8 parts of ammonium persulfate, 25 parts of propylene-hydroxypropyl acrylate copolymer, 25 parts of polyepoxysuccinic acid, 15 parts of benzotriazole, and 50 parts of deionized water.

[0036] Example 3

[0037] The specific preparation steps of the scale inhibitor are the same as those in Example 1, except that the components are adjusted by weight to 33 parts of hydrolyzed polymaleic anhydride, 19 parts of 2-acrylamide-2-methylpropylphosphonic acid, 8 parts of ammonium persulfate, 18 parts of propylene-hydroxypropyl acrylate copolymer, 24 parts of polyepoxysuccinic acid, 11 parts of benzotriazole and 40 parts of deionized water.

[0038] Example 4

[0039] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 33 parts of hydrolyzed polymaleic anhydride is adjusted to 32 parts of hydrolyzed polymaleic anhydride.

[0040] Example 5

[0041] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 19 parts of 2-acrylamide-2-methylpropylphosphonic acid is adjusted to 17 parts of 2-acrylamide-2-methylpropylphosphonic acid.

[0042] Example 6

[0043] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 11 parts of benzotriazole is adjusted to 11 parts of benzotriazole.

[0044] Example 7

[0045] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 24 parts of polyepoxysuccinic acid are adjusted to 18 parts of polyepoxysuccinic acid.

[0046] Comparative Example 1

[0047] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 33 parts of hydrolyzed polymaleic anhydride is adjusted to 15 parts of hydrolyzed polymaleic anhydride.

[0048] Comparative Example 2

[0049] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that hydrolyzed polymaleic anhydride is not added.

[0050] Comparative Example 3

[0051] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 19 parts of 2-acrylamide-2-methylpropylphosphonic acid are replaced by 10 parts of hydrolyzed polymaleic anhydride.

[0052] Comparative Example 4

[0053] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 2-acrylamide-2-methylpropylphosphonic acid is not added.

[0054] Comparative Example 5

[0055] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 24 parts of sodium polyepoxysuccinate are adjusted to 15 parts of sodium polyepoxysuccinate.

[0056] Comparative Example 6

[0057] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that sodium polyepoxysuccinate is not added.

[0058] Comparative Example 7

[0059] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that 11 parts of benzotriazole are adjusted to 5 parts of benzotriazole.

[0060] Comparative Example 8

[0061] The specific preparation steps of the scale inhibitor are the same as those in Example 3, except that benzotriazole is not added.

[0062] Table 1 Scale inhibition rate of scale inhibitors in Examples and Comparative Examples

[0063] Test items Scale inhibition rate (%) Example 1 95.1 Example 2 95.5 Example 3 96.7 Example 4 95.2 Example 5 95.4 Example 6 95 Example 7 95.3 Comparative Example 1 88.7 Comparative Example 2 86.4 Comparative Example 3 87.5 Comparative Example 4 88.9 Comparative Example 5 87.6 Comparative Example 6 88.5 Comparative Example 7 87.1 Comparative Example 8 84.6

[0064] From the above table, by comparing Examples 1-3, it can be found that the different raw material ratios between the components will have a certain impact on the scale inhibition effect of the scale inhibitor of the present invention. The optimal ratio is 33 parts of hydrolyzed polymaleic anhydride, 19 parts of 2-acrylamide-2-methylpropylphosphonic acid, 8 parts of ammonium persulfate, 18 parts of propylene-hydroxypropyl acrylate copolymer, 24 parts of polyepoxysuccinic acid, 11 parts of benzotriazole and 40 parts of deionized water provided in Example 3, and its scale inhibition rate is 96.7.

[0065] By comparing Examples 3-4 with Comparative Examples 1-2, it can be found that when the ratio of hydrolyzed polymaleic anhydride changes, the scale inhibition effect of the prepared scale inhibitor will also change. If hydrolyzed polymaleic anhydride is not added, the carbonate compounds formed by the metal ions in the highly concentrated brine and other components in the scale inhibitor have low solubility and are not easily soluble in water, causing the formed compounds to clog the equipment; if the amount of hydrolyzed polymaleic anhydride added is not within the range provided by the present invention, if the amount added is too small, the metal ions in the water will not be able to react completely, and residues will be left, causing corrosion damage to the surface of the equipment; if too much is added, the compounds formed by the reaction of hydrolyzed polymaleic anhydride with ions in the water will be unstable and easily decomposed, resulting in low scale inhibition efficiency of the scale inhibitor.

[0066] It can be seen from Comparative Examples 3, 5 and 3-4 that when the mass fraction of 2-acrylamide-2-methylpropylphosphonic acid added in the present invention changes, the scale inhibition effect of the prepared scale inhibitor will also be affected. If 2-acrylamide-2-methylpropylphosphonic acid is not added, the scale inhibitor will not react completely with the metal ions in the water, and the formed compound is not easily soluble in water, which will clog the equipment. This is because the present invention uses 2-acrylamide-2-methylpropylphosphonic acid to hydrolyze polymaleic anhydride, which can make the water The metal ions in the water can better form a complex that is easily soluble in water, and 2-acrylamide-2-methylpropylphosphonic acid can change the chemical balance in the water, making the balance between carbonate and phosphate in the water more inclined to phosphate. Phosphate is one of the main components of scale, and phosphate has a low solubility, so that the complex finally formed by the scale inhibitor will not clog the equipment; if too much is added, the compound formed by the scale inhibitor and the metal ions in the water will be unstable; if too little is added, the reaction between the hydrolyzed polymaleic anhydride and the metal ions in the water will be incomplete.

[0067] By comparing Example 3, Example 6 and Comparative Examples 5-6, it can be seen that when the mass fraction of sodium polyepoxysuccinate added in the present invention changes, the scale inhibition efficiency of the scale inhibitor will be affected. If sodium polyepoxysuccinate is not added, the scale inhibitor will not be able to form a more stable chelate with the metal ions in the water. This is because its molecules contain two functional groups, carboxyl and ether, which can have a synergistic effect with the hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid to achieve a slow-release synergistic effect, thereby improving the scale inhibition effect of the scale inhibitor.

[0068] The present invention further adds benzotriazole to enhance the scale inhibition effect of the scale inhibitor. As can be seen from Example 3, Example 7, and Comparative Examples 7-8, the present invention enhances the scale inhibition effect of the scale inhibitor by adding benzotriazole in combination with the hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid in the scale inhibitor, thereby allowing the hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid to react with metal ions in water to form a more stable chelate.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wastewater reuse membrane concentrated high-concentration brine scale inhibitor, characterized in that: The invention is mainly prepared from the following raw materials, in parts by mass: 20-35 parts of hydrolyzed polymaleic anhydride, 12-25 parts of 2-acrylamide-2-methylpropylphosphonic acid, 5-8 parts of ammonium persulfate, 10-25 parts of propylene-hydroxypropyl acrylate copolymer, 15-25 parts of polyepoxysuccinic acid, 5-15 parts of benzotriazole and 30-50 parts of deionized water; The scale inhibitor is prepared by the following steps: Add hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid, heat and stir; Add ammonium persulfate to the mixture of hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid, then raise the temperature and continue the reaction for 3 hours; After the temperature is allowed to stand at 20-25° C., propylene-hydroxypropyl acrylate copolymer, polyepoxysuccinic acid, benzotriazole and deionized water are sequentially added to the solution to which ammonium persulfate has been added, and the mixture is stirred.

2. The wastewater reuse membrane concentrated high-concentration brine scale inhibitor according to claim 1, characterized in that: The invention is mainly prepared from the following raw materials: 30-35 parts of hydrolyzed polymaleic anhydride, 16-25 parts of 2-acrylamide-2-methylpropylphosphonic acid, 7-8 parts of ammonium persulfate, 15-25 parts of propylene-hydroxypropyl acrylate copolymer, 20-25 parts of polyepoxysuccinic acid, 10-15 parts of benzotriazole and 35-50 parts of deionized water.

3. The wastewater reuse membrane concentrated high-concentration brine scale inhibitor according to claim 1, characterized in that: It is mainly prepared from the following raw materials: 33 parts of hydrolyzed polymaleic anhydride, 19 parts of 2-acrylamide-2-methylpropylphosphonic acid, 8 parts of ammonium persulfate, 18 parts of propylene-hydroxypropyl acrylate copolymer, 24 parts of polyepoxysuccinic acid, 11 parts of benzotriazole and 40 parts of deionized water.

4. The wastewater reuse membrane concentrated high-concentration brine scale inhibitor according to claim 1, characterized in that: After adding hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid, the temperature was raised to 43-47°C and stirring was continued for 30 minutes.

5. The wastewater reuse membrane concentrated high-concentration brine scale inhibitor according to claim 1, characterized in that: Sodium persulfate was added to the mixture of hydrolyzed polymaleic anhydride and 2-acrylamide-2-methylpropylphosphonic acid three times with an interval of 60 minutes each time. After the addition, the temperature was raised to 58-62°C and maintained at the temperature.

6. The wastewater reuse membrane concentrated high-concentration brine scale inhibitor according to claim 1, characterized in that: Propylene-hydroxypropyl acrylate copolymer, polyepoxysuccinic acid, benzotriazole and deionized water were added in sequence, and the mixture was stirred for 30 minutes.