A high-sulfate reverse osmosis scale inhibitor suitable for iron phosphate production wastewater treatment and a preparation method thereof

Abstract

The application discloses a high-sulfate reverse osmosis scale inhibitor suitable for iron phosphate production wastewater treatment, a reverse osmosis scale inhibitor under high-sulfate working conditions and a preparation method thereof. The reverse osmosis scale inhibitor contains the following raw materials in the following proportions: 10-20 wt% of a binary copolymer, 10-20 wt% of 2-phosphonate butane-1,2,4-tricarboxylic acid, 8-10 wt% of ethylenediamine tetramethylene phosphonic acid sodium, 6-10 wt% of aminotri-methylene phosphonic acid and the rest of ultra-pure water, with the total mass of the reverse osmosis scale inhibitor being 100%. The application utilizes maleic anhydride and sulfonate radical polymerization to prepare a novel binary copolymer for high-sulfate water quality system. The reverse osmosis scale inhibitor can effectively inhibit the formation of calcium sulfate scale on the concentrated water side of the reverse osmosis membrane under low dosage concentration, especially in the iron phosphate production wastewater membrane concentration system, and has good calcium sulfate scale inhibition effect under the condition that the sulfate content is as high as 50 g / L. Meanwhile, the raw materials are harmless to the environment and can be degraded, and belong to the environment-friendly reverse osmosis agent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial water treatment, and particularly relates to a reverse osmosis scale inhibitor suitable for a high sulfate working condition and a preparation method thereof, in particular to a reverse osmosis scale inhibitor for calcium sulfate in a membrane concentration system of iron phosphate production wastewater. BACKGROUND

[0002] The reverse osmosis technology is a membrane separation filtration technology, and the membrane aperture thereof is extremely small. Under the action of a certain pressure driving, organic matters, colloids, heavy metal ions, bacteria and viruses and other impurities in raw water can be effectively removed, so that the purpose of water purification is achieved. The separation process is efficient, environmentally friendly and widely applicable.

[0003] In recent years, with the rapid development of the electric vehicle industry, the demand market for lithium iron phosphate positive electrode materials is becoming larger and larger, and the demand for iron phosphate raw materials as precursors also increases. The ammonia method iron phosphate production process using ferrous sulfate as raw material to synthesize iron phosphate has become the mainstream production process of iron phosphate because of its high product purity and stable performance. However, a large amount of high-salinity wastewater is generated in the production process, such as synthesis, water washing and the like. In order to achieve the purpose of zero discharge and recycling of wastewater, multi-stage reverse osmosis membrane separation and concentration technology is widely used in the treatment of such wastewater. The mother liquor and washing water generated in the production process of iron phosphate are high-salinity inorganic wastewater containing different concentrations of metal ions such as iron, manganese, calcium and magnesium, ammonium ions, sulfate ions and phosphate ions. The content of sulfate is as high as 50 g / L (see the table below). With the concentration and separation process of wastewater in the multi-stage membrane concentration system, the content of sulfate on the concentrated water side is getting higher and higher, and the scaling tendency of calcium sulfate is also more likely to form. The surface of the reverse osmosis membrane is also easily contaminated by inorganic salt scale, which reduces the water production rate of the system and has a great impact on the entire production process.

[0004] Table 1 Water quality characteristics of iron phosphate production wastewater into the membrane concentration system

[0005]

[0006] Chinese patents with publication numbers CN114772755A and CN107758882A respectively disclose a high-sulfate-resistant reverse osmosis scale inhibitor and a preparation method thereof, which can meet the scale inhibition requirements of high-sulfate water quality. However, the concentrations of calcium ions and sulfates can only reach 18 g / L and 11.5 g / L respectively.

[0007] At present, there are few reverse osmosis scale inhibitors specially developed for the characteristics of iron phosphate production wastewater. For the characteristics of iron phosphate production wastewater, the contents of sulfate, phosphate, ammonium, calcium and salt are very high. The existing sulfate reverse osmosis scale inhibitor is only suitable for ordinary water quality and cannot meet the performance requirements of high-salinity water quality. SUMMARY

[0008] In order to solve the problems in the prior art, the application provides a reverse osmosis scale inhibitor suitable for high sulfate working conditions and a preparation method thereof, in particular a reverse osmosis scale inhibitor for calcium sulfate in a membrane concentration system of iron phosphate production wastewater.

[0009] To achieve the above object, the application provides the following technical scheme.

[0010] The reverse osmosis scale inhibitor suitable for high sulfate working conditions comprises the following proportions of raw materials:

[0011] The reverse osmosis scale inhibitor comprises the following proportions of raw materials: 10-20 parts of a binary copolymer, 10-20 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, 10-30 parts of sodium ethylenediaminetetramethylene phosphonate, 5-18 parts of aminotrimethylene phosphonic acid, 0.1-1 part of 4,4',4''-phosphoryl triphenylmethane, and 10-30 parts of ultrapure water.

[0012] In some preferred embodiments, the reverse osmosis scale inhibitor comprises the following proportions of raw materials: 18 parts of a binary copolymer, 18 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, 15 parts of sodium ethylenediaminetetramethylene phosphonate, 10 parts of aminotrimethylene phosphonic acid, 0.5 part of 4,4',4''-phosphoryl triphenylmethane, and 13 parts of ultrapure water.

[0013] The binary copolymer is prepared by maleic anhydride and sulfonate radical polymerization.

[0014] The sulfonate is selected from one or more of sodium allylsulfonate, sodium allyloxyhydroxypropyl sulfonate, sodium methacrylsulfonate, sodium alpha-alkenyl sulfonate, and sodium lignosulfonate.

[0015] The preparation method of the binary copolymer is as follows:

[0016] S1: maleic anhydride and water are mixed and stirred to dissolve;

[0017] S2: sodium ethylenediaminetetraacetate is dissolved in an aqueous solution and added dropwise to S1, stirring and controlling the pH value of the reaction solution to be 4.0-4.5;

[0018] S3: after the dropwise addition is completed, sulfonate is added, nitrogen is introduced, and the temperature is increased to 60-100 DEG C under stirring,

[0019] S4: after the reaction is completed, ammonium persulfate solution is added dropwise, and after the dropwise addition is completed, the reaction is carried out at 75-85 DEG C under heat preservation;

[0020] S5: After the reaction is completed, the temperature is lowered to normal temperature, and then the filter is unloaded to obtain the binary copolymer.

[0021] The mass ratio of maleic anhydride, sodium ethylenediaminetetraacetate, sulfonate, and ammonium persulfate is 1:0.1-0.5:1-2:0.1-0.4.

[0022] The preparation method of the reverse osmosis scale inhibitor suitable for high sulfate working conditions comprises the following operation steps:

[0023] S1: Sodium ethylenediaminetetraethylene phosphonate and aminotri-methylene phosphonic acid are sequentially added to water, and mixed until uniform;

[0024] S3: 2-Phosphonic acid butane-1,2,4-tricarboxylic acid and the binary copolymer are added to S1, and stirred for 1-2 h, then 4,4',4"-phosphoryl tribenzoic acid is added, and stirred at 50-80 DEG C for 10-30 min, and then filtered and unloaded to obtain the reverse osmosis scale inhibitor suitable for high sulfate working conditions.

[0025] The application utilizes maleic anhydride and sulfonate radical polymerization to prepare a novel binary copolymer for high sulfate influent water quality system; the reverse osmosis scale inhibitor of the application further adds 4,4',4"-phosphoryl tribenzoic acid, which can effectively inhibit the formation of calcium sulfate scale on the concentrated water side of the reverse osmosis membrane at a low dosage concentration, especially has a good calcium sulfate scale inhibition effect in the membrane concentration system of the phosphoric acid iron production wastewater; meanwhile, the raw materials of the components are harmless to the environment and biodegradable, and belong to the environment-friendly reverse osmosis agent. DETAILED DESCRIPTION

[0026] The application will be further described below in combination with examples, but the scope of protection claimed by the application is not limited to the scope expressed in the examples.

[0027] The severe properties of the phosphoric acid iron production wastewater in the case are shown in Table 2

[0028] The water quality characteristics of the mother liquor and washing water generated in the phosphoric acid iron production process

[0029]

[0030] Example 1

[0031] The preparation method of the binary copolymer is as follows:

[0032] S1: 8 KG of maleic anhydride and 65 KG of ultrapure water are added to a reaction stirring kettle and stirred and dissolved;

[0033] S2: 1 KG of sodium ethylenediaminetetraacetate is dissolved in 4 KG of ultrapure water, and then delivered to a high tank 1 and slowly added to the reaction stirring kettle, and the pH value of the solution in the reaction stirring kettle is controlled to be 4.0-4.5;

[0034] S3: Add 10 kg of sodium allyl sulfonate to the reaction stirred tank and stir to dissolve;

[0035] S4: Slowly introduce steam into the interlayer of the reaction stirring kettle, raise the temperature to 80°C and keep it stable, and simultaneously introduce nitrogen into the kettle from the bottom of the reaction stirring kettle;

[0036] S5: Dissolve 2 kg of ammonium persulfate in 18 kg of ultrapure water, transfer to the header tank 2, and slowly add dropwise to the reaction stirred tank for 1 hour;

[0037] S6: After the addition is complete, continue stirring for 3 h, maintaining the temperature at 75-85°C;

[0038] S7: After the heat preservation process is completed, the temperature is lowered to room temperature and then filtered and discharged to obtain a binary copolymer.

[0039] Example 2

[0040] The preparation method of reverse osmosis scale inhibitor suitable for high sulfate working conditions is as follows:

[0041] S1: 13 kg of ultrapure water is delivered to the reaction stirred tank;

[0042] S2: 15 kg of sodium ethylenediaminetetramethylenephosphonate and 10 kg of aminotrimethylenephosphonic acid were added to the reaction stirred tank in sequence and mixed evenly;

[0043] S3: 18 kg of 2-phosphonobutane-1,2,4-tricarboxylic acid and 18 kg of the binary copolymer prepared in Example 1 were added to a stirred reactor in sequence. The reaction was stirred for 1 hour. Then, 0.5 parts of 4,4′,4″-phosphoryltribenzoic acid were added. The mixture was stirred at 70-80°C for 15 minutes. The mixture was filtered and discharged to obtain a reverse osmosis scale inhibitor suitable for high sulfate working conditions.

[0044] Example 3

[0045] The preparation method of reverse osmosis scale inhibitor suitable for high sulfate working conditions is as follows:

[0046] S1: 13 kg of ultrapure water is delivered to the reaction stirred tank;

[0047] S2: 8 kg of sodium ethylenediaminetetramethylenephosphonate and 18 kg of aminotrimethylenephosphonic acid were added to the reaction stirred tank in sequence and mixed evenly;

[0048] S3: 20 kg of 2-phosphonobutane-1,2,4-tricarboxylic acid and 11 kg of the binary copolymer prepared in Example 1 were added to a stirred reactor in sequence. The reaction was stirred for 1 hour. Then, 0.1 parts of 4,4′,4″-phosphoryltribenzoic acid were added. The mixture was stirred at 70-80° C. for 15 minutes. The mixture was filtered and discharged to obtain a reverse osmosis scale inhibitor suitable for high sulfate working conditions.

[0049] Comparative Example 1

[0050] The preparation method of the reverse osmosis scale inhibitor and dispersant is the same as that of Example 2, except that the binary copolymer prepared in Example 1 is not added.

[0051] Comparative Example 2

[0052] The preparation method of the reverse osmosis scale inhibitor and dispersant is the same as that of Example 2, except that the 4,4′,4″-phosphoryltribenzoic acid prepared in Example 1 is not added.

[0053] The reverse osmosis scale inhibitor and dispersant suitable for high sulfate working conditions prepared in the embodiment of the present invention was subjected to a comparative experiment with a comparative example. A calcium sulfate scale inhibition experiment was conducted according to Q / SY17126-2019 "Technical Requirements for Corrosion and Scale Inhibitors for Oilfield Water Treatment"; scale inhibition tests were conducted on wash water and mother liquor respectively, with sulfate ion concentrations of 50,000 ppm, ammonium ion concentrations of 10,000 ppm, phosphate ion concentrations of 900 ppm, calcium ion concentrations of 1,000 ppm, and agent concentrations of 15 ppm. The experimental results are shown in Table 1:

[0054]

Claims

1. A high sulfate reverse osmosis scale inhibitor suitable for treating wastewater from iron phosphate production, characterized in that: The reverse osmosis scale inhibitor comprises raw materials in the following proportions: 10-20 parts of a binary copolymer, 10-20 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, 10-30 parts of sodium ethylenediaminetetramethylenephosphonate, 5-18 parts of aminotrimethylenephosphonic acid, 0.1-1 part of 4,4′,4″-phosphoryltribenzoic acid, and 10-30 parts of ultrapure water. The preparation method of the binary copolymer is as follows: S1: Mix maleic anhydride and water and stir to dissolve; S2: Sodium EDTA is dissolved in an aqueous solution and added dropwise to S1, stirring and controlling the pH value of the reaction solution to 4.0-4.5; S3: After the dropwise addition is completed, sulfonate is added, and the sulfonate is selected from one or more of sodium allyl sulfonate, sodium allyloxyhydroxypropyl sulfonate, sodium methacrylate sulfonate, sodium α-olefin sulfonate, and sodium lignin sulfonate. The mixture is heated to 60-100°C under nitrogen and stirring. S4: After the reaction is complete, add ammonium persulfate solution dropwise, and keep the temperature at 75-85°C for reaction; S5: After the reaction is completed, the temperature is cooled to room temperature and then filtered and discharged to obtain a binary copolymer.

2. The high sulfate reverse osmosis scale inhibitor suitable for treating ferric phosphate production wastewater according to claim 1, characterized in that: The reverse osmosis scale inhibitor comprises raw materials in the following proportions: 18 parts of binary copolymer, 18 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, 15 parts of sodium ethylenediaminetetramethylenephosphonate, 10 parts of aminotrimethylenephosphonic acid, 0.5 parts of 4,4',4"-phosphoryltribenzoic acid and 13 parts of ultrapure water.

3. The high sulfate reverse osmosis scale inhibitor suitable for treating ferric phosphate production wastewater according to claim 1, characterized in that: The mass ratio of maleic anhydride, sodium ethylenediaminetetraacetate, sulfonate and ammonium persulfate is 1:0.1-0.5:1-2:0.1-0.

4.

4. The method for preparing a high sulfate reverse osmosis scale inhibitor suitable for treating wastewater from ferric phosphate production according to any one of claims 1 to 3, characterized in that: The following steps are included: S1: Add sodium ethylenediaminetetramethylenephosphonate and aminotrimethylenephosphonic acid into ultrapure water in sequence and mix until uniform; S3: Add 2-phosphonobutane-1,2,4-tricarboxylic acid and the binary copolymer to S1, stir the reaction for 1-2 hours, then add 4,4′,4″-phosphoryltribenzoic acid, stir at 50-80°C for 10-30 minutes, filter and discharge the material to obtain a reverse osmosis scale inhibitor suitable for high sulfate working conditions.

Images