High-efficiency sewage treatment agent, preparation method thereof and application thereof in steelmaking wastewater

Abstract

The application discloses a high-efficiency sewage treatment agent, a preparation method thereof and application of the high-efficiency sewage treatment agent in steelmaking wastewater, and relates to the technical field of water pollution treatment. The high-efficiency sewage treatment agent comprises the following raw materials in parts by weight: diatomite 20-25 parts, bentonite 18-22 parts, coconut shell activated carbon 20-25 parts, a flocculant 10-13 parts and a coagulant aid 7-8 parts. The high-efficiency sewage treatment agent prepared by the application can effectively remove the chemical oxygen demand, suspended solids and ammonia nitrogen content in wastewater.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water pollution treatment, in particular to a high-efficiency sewage treatment agent, a preparation method thereof and application thereof in steelmaking wastewater. BACKGROUND

[0002] The steelmaking wastewater is an industrial wastewater with complex composition and high pollution load, and its efficient treatment and reuse is a key difficulty for the green development of the steel industry. At present, the traditional process with "lime softening-coagulation sedimentation" as the core is generally used in the industry, and conventional reagents such as polyaluminum chloride and polyacrylamide are relied on. However, this process has limitations in treating the specific pollutants in steelmaking wastewater. First, in terms of chemical oxygen demand (COD) removal, the wastewater contains a large amount of emulsified oil from roll lubrication and corrosion-resistant coating and part of the dissolved organic matter, and the conventional coagulant is difficult to effectively demulsify and adsorb, resulting in incomplete COD removal and unstable effluent quality. Secondly, the ability to capture suspended solids such as fine iron oxide scale and colloidal substances is limited, and in order to ensure the effect, the reagent needs to be added in excess, which not only has high cost, but also produces chemical sludge with loose structure and high water content, greatly increasing the subsequent disposal burden. In addition, the traditional coagulation sedimentation method has limited effect on ammonia nitrogen removal, which poses a risk of eutrophication in the effluent and restricts the recycling of the wastewater.

[0003] The Chinese patent with the publication number CN106830120A discloses a sewage treatment agent with demulsification function, a preparation method and application thereof. The sewage treatment agent is composed of the following raw materials in parts by weight: vermiculite 27-35 parts, propargyl chloride 11-19 parts, fumaric acid 4-8 parts, methyltributylketoximosilane 1-5 parts, chitin 19-27 parts. The sewage treatment agent prepared by the present application has fast settling speed, small dosage, strong impact resistance and no corrosion to equipment, but its ability to reduce chemical oxygen demand and ammonia nitrogen content needs to be improved. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application aims to provide a high-efficiency sewage treatment agent, a preparation method thereof and application thereof in steelmaking wastewater.

[0005] To achieve the above-mentioned purpose, the present application realizes the following technical solutions:

[0006] A high-efficiency sewage treatment agent comprises the following raw materials in parts by weight:

[0007] 20-25 parts of diatomite, 18-22 parts of bentonite, 20-25 parts of coconut activated carbon, 10-13 parts of flocculant and 7-8 parts of coagulant aid;

[0008] The flocculant is prepared by the following method:

[0009] S1: 6-chloro-6-oxohexanoic acid is reacted with 6-hydroxyhexyl methacrylate to form 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid,

[0010] S2: 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid is reacted with 1,2-bis(bromoacetyloxy)ethane in the presence of a catalyst and an organic ligand to form polymer 1,

[0011] S3: Polymer 1 is reacted with 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt to form a flocculant.

[0012] The molar ratio of the 6-chloro-6-oxohexanoic acid to the 6-hydroxyhexyl methacrylate is (1.1-1.3):1.

[0013] The molar ratio of the 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid to the 1,2-bis(bromoacetyloxy)ethane is (10-14):1.

[0014] The molar ratio of the polymer 1 to the 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt is 1:(2-6).

[0015] The coagulant aid is sodium polyacrylate.

[0016] In step S2, the catalyst is cuprous bromide.

[0017] In step S2, the organic ligand is pentamethyldiethylenetriamine.

[0018] The bentonite is of the type 38.

[0019] A preparation method of a high-efficiency sewage treatment agent, comprising the following steps:

[0020] (1) Pretreatment: diatomite, bentonite and coconut activated carbon are respectively crushed by a crusher and sieved through a 200-mesh sieve;

[0021] (2) Weighing: diatomite 20-25 parts, bentonite 18-22 parts, coconut activated carbon 20-25 parts, flocculant 10-13 parts, and coagulant aid 7-8 parts by weight;

[0022] (3) The diatomite, bentonite and coconut activated carbon are stirred and uniformly mixed to obtain a mixture, and the flocculant and coagulant aid are slowly added to the mixture and stirred and uniformly mixed to obtain the high-efficiency sewage treatment agent.

[0023] The application of a high-efficiency sewage treatment agent in steelmaking wastewater.

[0024] As the above technical solutions are adopted, the present application has the following beneficial effects:

[0025] The high-efficiency sewage treatment agent prepared by the present application can effectively reduce the content of COD, suspended solids and ammonia nitrogen in wastewater. DETAILED DESCRIPTION

[0026] The present application will be further described in conjunction with the following examples, but the present application is not limited to these examples.

[0027] Example 1: Preparation of a flocculant

[0028] S1: Under nitrogen protection, 200 ml of dichloromethane, 0.1 mol of 6-hydroxyhexyl methacrylate, 2 g of 4-dimethylaminopyridine (DMAP), 0.12 mol of triethylamine were added to a reactor under ice bath, 0.11 mol of 6-chloro-6-oxohexanoic acid was slowly added dropwise for 20 min, and then the temperature was raised to room temperature after dropping, and the reaction was carried out for 4 h. Then the reaction liquid was poured into 200 ml of 0.5M dilute hydrochloric acid solution, and the organic phase was washed with 100 ml of deionized water and 100 ml of saturated brine in turn, and then dried with 20 g of anhydrous sodium sulfate for 2 h, filtered, distilled at 30°C under reduced pressure for 3 h, and dried at 40°C under vacuum for 10 h to obtain 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid. The reaction equation is shown as follows:

[0029] .

[0030] The nuclear magnetic resonance hydrogen spectrum data are as follows:

[0031] 1 H NMR (400 MHz, Chloroform- d ) δ 10.38 (s, 1H), 5.91 – 5.42 (m, 2H),4.12 (q, J = 6.3 Hz, 4H), 2.52 – 2.25 (m, 2H), 2.19 – 2.02 (m, 2H), 1.93 (dd,J = 1.4, 0.9 Hz, 3H), 1.76 – 1.54 (m, 8H), 1.34 – 1.09 (m, 4H).

[0032] S2: Under nitrogen protection, 200 ml of toluene, 0.1 mol of 6-[(6-methyl acryloyloxy hexyl)oxy]-6-oxohexanoic acid, 0.01 mol of 1,2-bis(bromoacetyloxy)ethane, 0.6 g of pentamethyldiethylenetriamine were added into a reactor, stirred and mixed, 1.8 g of cuprous bromide was added, heated to 80°C, reacted for 3 h, then cooled to room temperature, removed the copper catalyst by neutral alumina column, to obtain a crude product, the crude product was dissolved in 1000 ml of tetrahydrofuran, 60°C rotary evaporation for 30 min to form a concentrated solution, under the condition of magnetic stirring, the concentrated solution was slowly added to 600 ml of cold acetone, dropwise for 30 min, stirred, precipitated, filtered, and vacuum dried at 70°C for 6 h to obtain polymer 1; the number average molecular weight was 3440; the reaction equation is as follows:

[0033] .

[0034] The nuclear magnetic resonance hydrogen spectrum data are as follows:

[0035] 1 H NMR (400 MHz, Chloroform- d ) δ 10.33 (s, 10H), 4.31 (s, 4H), 4.23 –4.03 (m, 40H), 2.73 – 2.52 (m, 20H), 2.45 (ddd, J = 14.9, 8.7, 8.3 Hz, 2H),2.29 (dt, J = 10.8, 8.6 Hz, 40H), 2.19 (dt, J = 14.9, 8.4 Hz, 2H), 1.86 (s,30H), 1.74 – 1.67 (m, 40H), 1.65 – 1.55 (m, 40H), 1.51 – 1.38 (m, 40H).

[0036] S3: Under nitrogen protection, 200 ml of tetrahydrofuran, 0.01 mol of polymer 1 were added into a reactor, stirred and mixed, then 50 ml of deionized water solution containing 0.02 mol of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 2.5 g of pentamethyldiethylenetriamine and 2 g of cuprous bromide were added, stirred and mixed, refluxed for 4 h, then reduced to room temperature, removed the copper catalyst by a neutral alumina column, obtained a crude product, dissolved the crude product in 1000 ml of tetrahydrofuran, stirred in an ice bath, added 0.105 mol of NaHCO3 in 5 batches (5 min interval between batches), then stirred for 30 min; 60°C rotary evaporation for 30 min, washed with cold deionized water (5°C) (3x50 ml), 60°C vacuum drying for 8 h to obtain a flocculant; the number average molecular weight is 4220; the reaction equation is as follows:

[0037] .

[0038] The nuclear magnetic resonance hydrogen spectrum data are as follows:

[0039] 1 H NMR (400 MHz, Chloroform- d ) δ 4.54 – 4.42 (m, 4H), 4.31 (s, 4H),4.23 – 4.07 (m, 40H), 3.96 – 3.82 (m, 6H), 3.66 (d, J = 11.5 Hz, 2H), 3.53(t, J = 9.5 Hz, 4H), 3.22 (d, J = 0.8 Hz, 12H), 2.87 (td, J = 11.4, 0.6 Hz,4H), 2.51 (dt, J = 16.1, 8.1 Hz, 2H), 2.41 – 2.33 (m, 2H), 2.31 – 2.21 (m,44H), 2.02 (dt, J = 14.3, 8.1 Hz, 20H), 1.77 – 1.66 (m, 40H), 1.65 – 1.55 (m,40H), 1.51 – 1.40 (m, 40H), 1.33 (d, J = 14.9 Hz, 36H)。

[0040] Example 2 Preparation of flocculant:

[0041] S1 : Under nitrogen protection, 200 ml of dichloromethane, 0.1 mol of 6- hydroxyhexyl methacrylate, 2 g of 4-dimethylaminopyridine (DMAP), 0.12 mol of triethylamine were added into a reactor under ice bath, 0.12 mol of 6-chloro-6- oxohexanoic acid was slowly added dropwise for 20 min, and then the temperature was raised to room temperature after the dropwise addition was completed. After 3 h of reaction, the reaction solution was poured into 200 ml of 0.5 M dilute hydrochloric acid solution, and the organic phase was separated and washed with 100 ml of deionized water and 100 ml of saturated brine solution in sequence, and then dried with 20 g of anhydrous sodium sulfate for 2 h, filtered, and distilled at 30 °C under reduced pressure for 3 h, and then dried at 40 °C under vacuum for 10 h to obtain 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid.

[0042] S2: Under nitrogen protection, 200 ml of toluene, 0.12 mol of 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid, 0.01 mol of 1,2-bis(bromoacetyloxy)ethane, and 0.6 g of pentamethyldiethylenetriamine were added into a reactor, stirred and mixed, 1.8 g of cuprous bromide was added, and the temperature was raised to 75 °C. After 3.5 h of reaction, the temperature was lowered to room temperature, and the copper catalyst was removed by passing through a neutral alumina column to obtain a crude product. The crude product was dissolved in 1000 ml of tetrahydrofuran, and concentrated solution was formed by rotary evaporation at 60 °C for 30 min. Under the condition of magnetic stirring, the concentrated solution was slowly added dropwise into 600 ml of cold acetone, and the stirring was continued for 30 min. The precipitate was separated by filtration, and dried at 70 °C under vacuum for 6 h to obtain polymer 1. The number average molecular weight was 4070.

[0043] S3: Under nitrogen protection, 200 ml of tetrahydrofuran and 0.01 mol of polymer 1 were added into a reactor, stirred and mixed, and then 50 ml of a deionized water solution containing 0.04 mol of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 2.5 g of pentamethyldiethylenetriamine, and 2 g of cuprous bromide were added. After stirring and mixing, the reaction was carried out under reflux for 3 h, and then the temperature was lowered to room temperature. The copper catalyst was removed by passing through a neutral alumina column to obtain a crude product. The crude product was dissolved in 1000 ml of tetrahydrofuran, and 0.125 mol of NaHCO3 was added in 5 batches under ice bath stirring (5 min interval between batches), and then stirred for 30 min. Rotary evaporation was carried out at 60 °C for 30 min, and then washed with cold deionized water (5 °C) (3 x 50 ml). Finally, the flocculant was obtained by drying at 60 °C under vacuum for 8 h. The number average molecular weight was 5460.

[0044] Example 3: Preparation of a flocculant

[0045] S1: Under nitrogen protection, 200 ml of dichloromethane, 0.1 mol of 6-hydroxyhexyl methacrylate, 2 g of 4-dimethylaminopyridine (DMAP), 0.12 mol of triethylamine were added into a reactor under ice bath, 0.13 mol of 6-chloro-6-oxohexanoic acid was slowly added dropwise for 20 min, and the reaction was carried out at room temperature for 2 h. After the reaction, the reaction solution was poured into 200 ml of 0.5M dilute hydrochloric acid solution, and the organic phase was washed with 100 ml of deionized water and 100 ml of saturated brine in sequence, and then dried with 20 g of anhydrous sodium sulfate for 2 h. After filtration, the organic phase was distilled under reduced pressure at 30°C for 3 h, and then dried under vacuum at 40°C for 10 h to obtain 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid.

[0046] S2: Under nitrogen protection, 200 ml of toluene, 0.14 mol of 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid, 0.01 mol of 1,2-bis(bromoacetyloxy)ethane, and 0.6 g of pentamethyldiethylenetriamine were added into a reactor, stirred and mixed, 1.8 g of cuprous bromide was added, and the reaction was carried out at 70°C for 4 h. After the reaction, the reaction was cooled to room temperature, and the copper catalyst was removed by passing through a neutral alumina column to obtain a crude product. The crude product was dissolved in 1000 ml of tetrahydrofuran, and concentrated solution was formed by rotary evaporation at 60°C for 30 min. The concentrated solution was slowly added dropwise into 600 ml of cold acetone under magnetic stirring for 30 min, and the precipitate was separated by filtration and dried under vacuum at 70°C for 6 h to obtain polymer 1; the number average molecular weight was 4700.

[0047] S3: Under nitrogen protection, 200 ml of tetrahydrofuran and 0.01 mol of polymer 1 were added into a reactor, stirred and mixed, and then 50 ml of a deionized water solution containing 0.06 mol of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 2.5 g of pentamethyldiethylenetriamine, and 2 g of cuprous bromide were added. After stirring and mixing, the reaction was carried out under reflux for 2 h, and then the reaction was cooled to room temperature. The copper catalyst was removed by passing through a neutral alumina column to obtain a crude product. The crude product was dissolved in 1000 ml of tetrahydrofuran, and 0.145 mol of NaHCO3 was added in 5 batches under ice bath stirring (5 min interval between batches), and then stirred for 30 min. The product was washed with cold deionized water (5°C) (3×50 ml), and then dried under vacuum at 60°C for 8 h to obtain a flocculant; the number average molecular weight was 6690.

[0048] Example 4: Preparation of high-efficiency sewage treatment agent:

[0049] (1) Pretreatment: diatomite, bentonite, and coconut activated carbon were respectively crushed by a crusher and passed through a 200-mesh screen.

[0050] (2) Weighing: diatomite 200g, bentonite (Bentone® 38) 180g, coconut shell activated carbon 200g, flocculant (prepared in Example 1) 100g, coagulant (sodium polyacrylate) 70g;

[0051] (3) The diatomite, bentonite and coconut shell activated carbon are stirred and uniformly mixed to obtain a mixture, and the flocculant and coagulant are slowly added to the mixture, which is stirred and uniformly mixed to obtain the high-efficiency sewage treatment agent.

[0052] Example 5: Preparation of a high-efficiency sewage treatment agent

[0053] (1) Pretreatment: The diatomite, bentonite and coconut shell activated carbon are respectively crushed by a crusher and sieved through a 200-mesh sieve;

[0054] (2) Weighing: diatomite 220g, bentonite (Bentone® 38) 200g, coconut shell activated carbon 230g, flocculant (prepared in Example 2) 120g, coagulant (sodium polyacrylate) 75g;

[0055] (3) The diatomite, bentonite and coconut shell activated carbon are stirred and uniformly mixed to obtain a mixture, and the flocculant and coagulant are slowly added to the mixture, which is stirred and uniformly mixed to obtain the high-efficiency sewage treatment agent.

[0056] Example 6: Preparation of a high-efficiency sewage treatment agent

[0057] (1) Pretreatment: The diatomite, bentonite and coconut shell activated carbon are respectively crushed by a crusher and sieved through a 200-mesh sieve;

[0058] (2) Weighing: diatomite 250g, bentonite (Bentone® 38) 220g, coconut shell activated carbon 250g, flocculant (prepared in Example 3) 130g, coagulant (sodium polyacrylate) 80g;

[0059] (3) The diatomite, bentonite and coconut shell activated carbon are stirred and uniformly mixed to obtain a mixture, and the flocculant and coagulant are slowly added to the mixture, which is stirred and uniformly mixed to obtain the high-efficiency sewage treatment agent.

[0060] Comparative Example 1

[0061] The raw material ratio and preparation method of the high-efficiency sewage treatment agent are basically the same as those of Example 5, except that the flocculant is replaced by an equal amount of flocculant prepared by the following method:

[0062] The preparation method of the flocculant is basically the same as that of Example 2, except that the 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid in step S2 is replaced by an equal molar amount of succinic acid mono[2-[(2-methyl-acryloyl)oxy]ethyl] ester.

[0063] Comparative Example 2

[0064] The raw material ratio and preparation method of the high-efficiency sewage treatment agent are basically the same as those of Example 5, except that the flocculant is replaced with an equal weight of a flocculant prepared by the following method:

[0065] The preparation method of the flocculant is basically the same as that of Example 2, except that the feeding amount of 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid in step S2 is increased to 0.2 mol.

[0066] Comparative Example 3

[0067] The raw material ratio and preparation method of the high-efficiency sewage treatment agent are basically the same as those of Example 5, except that the flocculant is replaced with an equal weight of the polymer 1 prepared by step S2 of Example 2.

[0068] Comparative Example 4

[0069] The raw material ratio and preparation method of the high-efficiency sewage treatment agent are basically the same as those of Example 5, except that the flocculant is replaced with an equal weight of a flocculant prepared by the following method:

[0070] The preparation method of the flocculant is basically the same as that of Example 2, except that 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt in step S3 is replaced with an equal molar amount of methacryloyloxyethyl trimethylammonium chloride.

[0071] Comparative Example 5

[0072] The raw material ratio and preparation method of the high-efficiency sewage treatment agent are basically the same as those of Example 5, except that the flocculant is replaced with an equal weight of a flocculant prepared by the following method:

[0073] Under nitrogen protection, 250 ml of toluene, 0.12 mol of 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid (prepared by step S1 of Example 2), and 0.04 mol of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt were added to a reactor, stirred and mixed, heated to 70°C, then 2 g of AIBN was added, reacted for 8 h, then slowly cooled to room temperature, stirred in an ice bath, and 0.125 mol of NaHCO3 was added in 5 batches (with an interval of 5 min), then stirred for 30 min; rotary evaporation at 60°C for 30 min, washed with cold deionized water (5°C) (3×50 ml), and vacuum dried at 60°C for 8 h to obtain the flocculant.

[0074] The diatomite SiO2 content used in the examples and comparative examples of the present application is 91.4 wt%, D50 = 150 μm, and is produced by Baishan Xingtai Diatomite New Material Co., Ltd.; the coconut shell activated carbon is coconut shell granular activated carbon with a particle size of 10-20 mesh, and is produced by Anguo Chengze Activated Carbon Manufacturing Co., Ltd.; the number average molecular weight of the sodium polyacrylate is 3500 Da.

[0075] The high-efficiency wastewater treatment agents prepared in the examples and comparative examples were subjected to chemical oxygen demand, suspended solids, and ammonia nitrogen content tests, and the test results are shown in Table 1.

[0076] A certain steel plant steelmaking wastewater (COD of 223 mg / L, suspended solids of 168 mg / L, and ammonia nitrogen content of 24.1 mg / L) was taken, divided into 8 portions, each 1000 ml, placed in a beaker, and 0.1 g of the high-efficiency wastewater treatment agents prepared in Examples 4-6 and Comparative Examples 1-5 was added, respectively, stirred at a speed of 350 r / min for 1 min, then stirred at a speed of 200 r / min for 2 min, and then stirred at a speed of 50 r / min for 2 min, and then left to stand for 20 min, 800 ml of supernatant was taken, stirred and mixed uniformly to serve as a test liquid, and subjected to chemical oxygen demand, suspended solids, and ammonia nitrogen content tests.

[0077] Chemical oxygen demand test: 10 ml of the test liquid was taken, and the chemical oxygen demand in the wastewater was determined according to the "GB / T 11914-1989 Water Quality-Determination of Chemical Oxygen Demand-Cerium (III) Sulphate Method".

[0078] Suspended solids test: the suspended solids in the wastewater were determined according to the "GB / T 11901-1989 Water Quality-Determination of Suspended Solids-Gravimetric Method".

[0079] Ammonia nitrogen content test: the ammonia nitrogen content in the wastewater was determined by spectrophotometry according to the "GB / T 7479-1987 Water Quality-Determination of Ammonium-Nessler's Reagent Colorimetric Method".

[0080] The removal rate of COD / suspended solids / ammonia nitrogen content is calculated according to the following formula:

[0081] Removal rate = ((C0-C) / C0) x 100%;

[0082] C0 represents the concentration of COD / suspended solids / ammonia nitrogen content in the wastewater before treatment; and C represents the concentration of COD / suspended solids / ammonia nitrogen content in the wastewater after treatment.

[0083] Table 1 Performance indicators of high-efficiency wastewater treatment agents

[0084]

[0085] As can be seen from Table 1, the sewage treatment agent prepared in the application can effectively reduce the contents of COD, suspended solids and ammonia nitrogen in wastewater.

[0086] The flocculant provided by the application is a functional polymer based on a di-ester-ethane main chain, which contains a plurality of 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoate sodium (anionic side chain) and a plurality of zwitterionic 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate inner salt (zwitterionic side chain). The anionic side chain in the flocculant combines with the dissolved organic pollutants (such as organic acids, dyes or oils) in the wastewater through electrostatic attraction and hydrophobic interaction to form a macromolecular complex; at the same time, the sulfonic acid group and the quaternary ammonium group of the zwitterionic side chain can further adsorb cationic, neutral or polar organic matter, and the hydrogen bond and van der Waals force are strengthened to form a dense floc, which significantly reduces the COD value. The di-ester-ethane main chain of the flocculant provides a flexible skeleton, which makes the side chain stretch and play a bridging role, the anionic group neutralizes the positively charged suspended particles (such as clay or microorganisms), and the zwitterionic group reduces the electrostatic repulsion between particles under charge balance, promotes the "bridging effect", and pulls the fine particles into larger flocs to accelerate gravity settling; in addition, the hydrophobic microzone of the di-ester group enhances the wrapping of colloidal particles, thereby realizing efficient settling and solid-liquid separation of suspended solids. For the removal of ammonia nitrogen, the sulfonate group of the zwitterionic side chain and the carboxylate of the anionic side chain specifically capture ammonium ions through the dual mechanisms of electrostatic attraction and ion exchange with quaternary ammonium cations, and the "inner salt pair" structure of the zwitterion further releases NH4 + The flocculant provided by the application realizes the synergy of hydrophobic adsorption, charge regulation, bridging flocculation and ion exchange as a whole, and through optimization of the distribution and density of the side chain, it avoids the phenomenon of restabilization caused by charge oversaturation, and ensures stable floc settling and efficient removal of COD, suspended solids and ammonia nitrogen.

[0087] When 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoate and 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonate inner salt are directly polymerized for flocculation, the di-ester-ethane flexible skeleton function will be lost, the bridging effect will be lost, and it cannot realize uniform distribution of the side chain, which further leads to a decrease in the removal rates of COD, suspended solids and ammonia nitrogen.

[0088] The above is only the preferred embodiment of the present application, and is not used to limit the present application; but for the ordinary skilled in the art without departing from the scope of the present application technical scheme, can use the above disclosed technical content and make some changes, modifications and evolution of equivalent changes, are equivalent embodiments of the present application; at the same time, any equivalent changes, modifications and evolution of the above embodiments according to the essential technology of the present application, still belong to the protection scope of the present application technical scheme.

Claims

1. A high-efficiency wastewater treatment agent, characterized in that, The ingredients include the following parts by weight: Diatomaceous earth 20-25 parts, bentonite 18-22 parts, coconut shell activated carbon 20-25 parts, flocculant 10-13 parts, coagulant aid 7-8 parts; The flocculant is prepared by the following method: S1: 6-Chloro-6-oxohexanoic acid reacts with 6-hydroxyhexyl methacrylate in the presence of 4-dimethylaminopyridine to generate 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid. S2: 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid reacts with 1,2-bis(bromoacetoxy)ethane in the presence of a catalyst and organic ligand to form polymer 1. S3: Polymer 1 reacts with 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt in the presence of cuprous bromide and pentamethyldiethylenetriamine to generate a flocculant; In step S1, the molar ratio of 6-chloro-6-oxohexanoic acid to 6-hydroxyhexyl methacrylate is (1.1-1.3):1; In step S2, the molar ratio of 6-[(6-methacryloyloxyhexyl)oxy]-6-oxohexanoic acid to 1,2-bis(bromoacetoxy)ethane is (10-14):

1. In step S3, the molar ratio of polymer 1 to 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt is 1:(2-6); In step S2, the catalyst is cuprous bromide; In step S2, the organic ligand is pentamethyldiethylenetriamine.

2. The high-efficiency wastewater treatment agent according to claim 1, characterized in that, The coagulant is sodium polyacrylate.

3. The high-efficiency wastewater treatment agent according to claim 1, characterized in that, The bentonite is designated as Bentone® 38.

4. A method for preparing the high-efficiency wastewater treatment agent according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Pretreatment: Diatomaceous earth, bentonite and coconut shell activated carbon are crushed by a pulverizer and passed through a 200-mesh sieve; (2) Weigh out the following by weight: 20-25 parts diatomaceous earth, 18-22 parts bentonite, 20-25 parts coconut shell activated carbon, 10-13 parts flocculant, and 7-8 parts coagulant aid; (3) Mix diatomaceous earth, bentonite and coconut shell activated carbon to obtain a mixture. Slowly add flocculant and coagulant aid to the mixture and stir until well mixed to obtain a high-efficiency wastewater treatment agent.

5. The application of the high-efficiency wastewater treatment agent according to any one of claims 1-3 in steelmaking wastewater.

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