Flocculating agent composition for petroleum refining sewage and preparation method thereof

Abstract

The invention relates to the technical field of flocculants, in particular to a flocculant composition for petroleum refining sewage and a preparation method thereof.The flocculant composition is prepared from, by weight, 5-6 parts of magnetic temperature-sensitive composite microspheres, 25-30 parts of polyionic liquid and 3.5-4 parts of polyaluminum ferric chloride; by compounding the magnetic temperature-sensitive composite microspheres and the polyion liquid, the problem that the existing flocculant is difficult to realize efficient separation of petroleum refining sewage is solved, and by introducing the magnetic nanoparticles and the temperature-sensitive structure, the flocculant composition has a good recycling effect, and is suitable for industrial production. And after being recycled and reused, the flocculant still can keep good flocculation capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of flocculants, and in particular to a flocculant composition for petroleum refining wastewater and a preparation method thereof. Background Art

[0002] Petroleum refinery wastewater has a complex composition, containing high-concentration emulsified oil, polycyclic aromatic hydrocarbons, heavy metal ions, and high salt content. Traditional flocculants, due to their single function and poor environmental adaptability, are unable to meet the requirements of flocculation treatment of petroleum refinery wastewater. For example, inorganic flocculants, such as polyferric sulfate and polyaluminum chloride, rely on charge neutralization, but have low efficiency in capturing nano-scale emulsified oil, and the hydrolysis of metal salts is limited in high-salt environments. Commonly used organic flocculants, such as patent CN101143743B "A Method for Preparing a Cationic Polymer Flocculant", use cationic polyacrylamide for wastewater and sludge treatment in the petroleum, petrochemical, chemical, and light industries. However, cationic polyacrylamide's molecular chains curl up in high-salt conditions, resulting in a loss of adsorption and bridging ability, which cannot meet the needs of petroleum refinery wastewater. Currently, commonly used flocculants on the market have difficulty achieving efficient separation of petroleum refinery wastewater and recycling flocculants, failing to meet market demand. Summary of the Invention

[0003] The present invention aims to provide a flocculant composition for petroleum refinery wastewater and a preparation method thereof. By compounding magnetic temperature-sensitive composite microspheres with polyionic liquids, the problem that existing flocculants are difficult to achieve efficient separation of petroleum refinery wastewater is solved. Moreover, by introducing magnetic nanoparticles and a temperature-sensitive structure, the flocculant composition has good recycling and reuse effects, and can still maintain good flocculation ability after recycling and reuse.

[0004] The object of the present invention can be achieved by the following technical solution: a method for preparing a flocculant composition for petroleum refinery wastewater, comprising the following steps: weighing the following raw materials in parts by weight: 5-6 parts of magnetic temperature-sensitive composite microspheres, 25-30 parts of polyionic liquid, and 3.5-4 parts of polyaluminum ferric chloride; mixing the magnetic temperature-sensitive composite microspheres, polyionic liquid, and polyaluminum ferric chloride to prepare a flocculant composition for petroleum refinery wastewater; The polyaluminium ferric chloride is Chengda PAFC, with a specification of 80 mesh.

[0005] The magnetic temperature-sensitive composite microspheres are prepared by the following steps: Step A1: Fe3O4 nanoparticles, an ammonia solution, ethanol, and deionized water were mixed and ultrasonically dispersed for 15-20 minutes. Tetraethoxysilane was added with stirring at a stirring rate of 120-140 rpm at room temperature, and the mixture was reacted for 3-3.5 hours. A mixed solution of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane, and ethanol was then added, and the mixture was heated to 30°C and reacted for 12-14 hours. The mixture was then magnetically separated, washed, and dried to obtain Precursor 1. The mass fraction of the ammonia solution is 25%, the volume ratio of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane and ethanol in the mixed solution is 0.1:1:10, and the amount ratio of ferrosoferric oxide nanoparticles, ammonia solution, ethanol, deionized water, tetraethoxysilane and mixed solution is 0.05-0.08 g:3.5-4 mL:60-70 mL:10-15 mL:1.2-1.5 mL:12-15 mL; During the reaction, a sol-gel method was used to provide an alkaline environment with aqueous ammonia solution. Tetraethoxysilane hydrolyzed and aggregated on the surface of ferrosoferric oxide nanoparticles to form silica. Simultaneously, 3-(isobutylacryloyloxy)propyltrimethoxysilane was added to modify the nanoparticles, introducing a double bond to produce precursor 1. The ferroferric oxide nanoparticles are ferroferric oxide from Zhongke Keyou, with a specification of 50-300nm.

[0006] Step A2: Precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, and 1,4-dioxane were mixed and ultrasonically dispersed for 15-20 minutes. Under nitrogen protection, a stirring rate of 180-200 rpm, and a temperature of 65°C, azobisisobutyronitrile was added with stirring, and the reaction was carried out for 10-12 hours. N-isopropylacrylamide was then added and the reaction was continued for 5-6 hours. Acrylamide was then added and the reaction was continued for 6-8 hours. The mixture was separated by magnetic attraction, washed, and dried to obtain Precursor 2. The amount ratio of precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, 1,4-dioxane, azobisisobutyronitrile, N-isopropylacrylamide and acrylamide is 0.08-0.1g: 0.01-0.012g: 60mL: 0.02-0.022g: 0.06-0.07g: 0.04-0.05g; During the reaction, under the action of azobisisobutyronitrile, the double bond in precursor 1 first reacts with the trithiosulfate structure in 2-cyano-2-propyldodecyl trithiocarbonate, and the initiator 2-cyano-2-propyldodecyl trithiocarbonate is grafted onto precursor 1. Then, through reversible addition-fragmentation chain transfer polymerization, it reacts with N-isopropylacrylamide and acrylamide to form a polyacrylamide grafted chain segment, thereby preparing precursor 2.

[0007] Step A3: Precursor 2 and deionized water were mixed and ultrasonically dispersed for 15-20 minutes. At a stirring rate of 120-180 rpm and room temperature, hydrofluoric acid was added and stirred for 15-18 minutes. The mixture was separated by magnetic attraction, washed, and dried to obtain magnetic thermosensitive composite microspheres. The mass fraction of hydrofluoric acid is 30%, and the ratio of precursor 2, deionized water and hydrofluoric acid is 0.08-0.1g:50-60mL:0.2-0.3mL; During the reaction, hydrofluoric acid is added to acid-dissolve and remove the silicon dioxide layer in the precursor 2, forming an intermediate hollow layer, so that the polyacrylamide grafted chain segments form a hollow porous shell outside the ferrosoferric oxide nanoparticles, thereby preparing magnetic thermosensitive composite microspheres.

[0008] The polyionic liquid is prepared by the following steps: Step B1: β-D-glucose pentaacetate, 3-bromopropanol and dichloromethane are mixed, stirred at a stirring rate of 140-160 rpm and room temperature, and boron trifluoride etherate is added, and the reaction is carried out for 12 hours. Dichloromethane / water is added for extraction, washing, and rotary evaporation to obtain bromopropylated glucose pentaacetate. Bromopropylated glucose pentaacetate and methanol are mixed, stirred at a stirring rate of 120-140 rpm and a temperature of 2-5°C, and sodium methoxide solution is added, and the reaction is carried out for 4-5 hours. The mixture is freeze-dried and washed to obtain bromopropylated glucose; The dosage ratio of β-D-glucose pentaacetate, 3-bromopropanol, dichloromethane and boron trifluoride etherate is 0.51-0.52 g: 1-1.05 g: 3-5 mL: 0.8-1 mL; the molar concentration of the sodium methoxide solution is 0.01 mol / L, and the dosage ratio of bromopropylated glucose pentaacetate, methanol and sodium methoxide solution is 0.28-0.3 g: 8-10 mL: 0.5-0.6 mL; During the reaction, under the action of boron trifluoride etherate, β-D-glucose pentaacetate reacts with 3-bromopropanol to introduce a bromopropyl structure to prepare bromopropylated glucose pentaacetate. Then, under the action of sodium methoxide solution, the acetate in the bromopropylated glucose pentaacetate is deprotected to prepare bromopropylated glucose.

[0009] Step B2: Bromopropylated glucose, N-vinylimidazole and acetonitrile are mixed, stirred at a rate of 120-180 rpm and a temperature of 75°C under nitrogen protection, reacted for 10-12 hours, rotary evaporated, rinsed, and dried to obtain quaternized glucose. Quaternized glucose, divinylbenzene, azobisisobutyronitrile and N, N-dimethylformamide are mixed, stirred at a rate of 120-180 rpm and a temperature of 75°C under nitrogen protection, reacted for 20-24 hours, filtered, washed, and vacuum dried to obtain a polyionic liquid; The ratio of bromopropylated glucose, N-vinylimidazole and acetonitrile is 0.32-0.35 g: 0.14-0.16 g: 20-25 mL; the ratio of quaternized glucose, divinylbenzene, azobisisobutyronitrile and N, N-dimethylformamide is 0.45-0.48 g: 0.95-1 g: 0.08-0.1 mL: 20-25 mL. During the reaction, bromopropylated glucose reacts with the imidazole structure in N-vinylimidazole to form an imidazolium structure to produce quaternized glucose. Then, under the action of azobisisobutyronitrile, the quaternized glucose and the double bond in divinylbenzene undergo polymerization to produce a polyionic liquid.

[0010] The invention has the beneficial effects of: disclosing a flocculant composition for petroleum refinery wastewater and a preparation method thereof. The invention comprises compounding magnetic thermosensitive composite microspheres with polyionic liquids. The magnetic thermosensitive composite microspheres use ferroferric oxide as a core, graft polymerize polyacrylamide segments on their surfaces, introduce N-isopropylacrylamide thermosensitive segments by reversible addition-fragmentation chain transfer polymerization, and compound with the polyionic liquids by non-covalent interaction. After flocculation, the flocculant composition is subjected to magnetic separation and a high-low temperature process, thereby solving the recycling process of the flocculant composition and maintaining good flocculation ability after recycling. The polyionic liquid is polymerized with quaternized glucose and divinylbenzene as monomers. The glucose unit and imidazolium structure of the polyionic liquid give the flocculant composition a good demulsification effect, and synergize with the magnetic thermosensitive composite microspheres having a hollow porous polyacrylamide shell layer. The flocculant can well polymerize microemulsion particles in petroleum refinery wastewater and is compounded with heavy metal ions to achieve a good flocculation and separation effect. DETAILED DESCRIPTION

[0011] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0012] Example 1 A method for preparing a flocculant composition for petroleum refinery wastewater comprises the following steps: weighing the following raw materials in parts by weight: 5 parts of magnetic temperature-sensitive composite microspheres, 25 parts of polyionic liquid, and 4 parts of polyaluminum ferric chloride; mixing the magnetic temperature-sensitive composite microspheres, polyionic liquid, and polyaluminum ferric chloride to prepare a flocculant composition for petroleum refinery wastewater; The polyaluminium ferric chloride is Chengda PAFC, with a specification of 80 mesh; The magnetic temperature-sensitive composite microspheres are prepared by the following steps: Step A1: Fe3O4 nanoparticles, an ammonia solution, ethanol, and deionized water were mixed and ultrasonically dispersed for 15 minutes. Tetraethoxysilane was added with stirring at a stirring rate of 120 rpm at room temperature and the mixture was reacted for 3 hours. A mixed solution of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane, and ethanol was then added and the mixture was heated to 30°C and reacted for 12 hours. The mixture was then magnetically separated, washed, and dried to obtain Precursor 1. The mass fraction of ammonia solution was 25%, the volume ratio of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane and ethanol in the mixed solution was 0.1:1:10, and the amount ratio of ferrosoferric oxide nanoparticles, ammonia solution, ethanol, deionized water, tetraethoxysilane and mixed solution was 0.05 g:3.5 mL:60 mL:10 mL:1.2 mL:12 mL; The ferroferric oxide nanoparticles are ferroferric oxide from Zhongke Keyou, with a specification of 50-300nm; Step A2: Precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, and 1,4-dioxane were mixed and ultrasonically dispersed for 15 minutes. Under nitrogen protection, a stirring rate of 180 rpm, and a temperature of 65°C, azobisisobutyronitrile was added with stirring, and the reaction was carried out for 10 hours. N-isopropylacrylamide was then added and the reaction was continued for 5 hours. Acrylamide was then added and the reaction was continued for 6 hours. The product was separated by magnetic attraction, washed, and dried to obtain Precursor 2. The amount ratio of precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, 1,4-dioxane, azobisisobutyronitrile, N-isopropylacrylamide and acrylamide is 0.08g:0.01g:60mL:0.02g:0.06g:0.04g; Step A3: Precursor 2 and deionized water were mixed and ultrasonically dispersed for 15 minutes. Under the conditions of stirring rate of 120 rpm and temperature at room temperature, hydrofluoric acid was added and reacted for 15 minutes. The mixture was separated by magnetic attraction, washed, and dried to obtain magnetic thermosensitive composite microspheres. The mass fraction of hydrofluoric acid is 30%, and the ratio of precursor 2, deionized water, and hydrofluoric acid is 0.08 g:50 mL:0.2 mL; The polyionic liquid is prepared by the following steps: Step B1: β-D-glucose pentaacetate, 3-bromopropanol, and dichloromethane were mixed, stirred at a stirring rate of 160 rpm and room temperature, and boron trifluoride etherate was added, and the mixture was reacted for 12 hours. Dichloromethane / water was added for extraction, washed, and rotary evaporated to obtain bromopropylated glucose pentaacetate. Bromopropylated glucose pentaacetate and methanol were mixed, stirred at a stirring rate of 120 rpm and a temperature of 5°C, and sodium methoxide solution was added, and the mixture was reacted for 4 hours. The mixture was freeze-dried and washed to obtain bromopropylated glucose. The dosage ratio of β-D-glucose pentaacetate, 3-bromopropanol, dichloromethane, and boron trifluoride etherate is 0.51 g:1 g:5 mL:0.8 mL; the molar concentration of the sodium methoxide solution is 0.01 mol / L, and the dosage ratio of bromopropylated glucose pentaacetate, methanol, and sodium methoxide solution is 0.28 g:10 mL:0.5 mL; Step B2: Bromopropylated glucose, N-vinylimidazole, and acetonitrile were mixed, stirred at 180 rpm, and 75° C. under nitrogen protection for 10 h, rotary evaporated, washed, and dried to obtain quaternized glucose. Quaternized glucose, divinylbenzene, azobisisobutyronitrile, and N, N-dimethylformamide were mixed, stirred at 180 rpm, and 75° C. under nitrogen protection for 24 h, filtered, washed, and vacuum dried to obtain a polyionic liquid. The usage ratio of bromopropylated glucose, N-vinylimidazole and acetonitrile is 0.32 g:0.14 g:25 mL; the usage ratio of quaternized glucose, divinylbenzene, azobisisobutyronitrile and N, N-dimethylformamide is 0.45 g:1 g:0.08 mL:20 mL.

[0013] Example 2 A method for preparing a flocculant composition for petroleum refinery wastewater comprises the following steps: weighing the following raw materials in parts by weight: 6 parts of magnetic temperature-sensitive composite microspheres, 25 parts of polyionic liquid, and 3.5 parts of polyaluminum ferric chloride; mixing the magnetic temperature-sensitive composite microspheres, polyionic liquid, and polyaluminum ferric chloride to prepare a flocculant composition for petroleum refinery wastewater; The polyaluminium ferric chloride is Chengda PAFC, with a specification of 80 mesh; The magnetic temperature-sensitive composite microspheres are prepared by the following steps: Step A1: Fe3O4 nanoparticles, an ammonia solution, ethanol, and deionized water were mixed and ultrasonically dispersed for 20 minutes. Tetraethoxysilane was added with stirring at a stirring rate of 120 rpm at room temperature and the mixture was reacted for 3 hours. A mixed solution of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane, and ethanol was then added and the mixture was heated to 30°C and reacted for 14 hours. The mixture was then magnetically separated, washed, and dried to obtain Precursor 1. The mass fraction of ammonia solution was 25%, the volume ratio of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane and ethanol in the mixed solution was 0.1:1:10, and the amount ratio of ferrosoferric oxide nanoparticles, ammonia solution, ethanol, deionized water, tetraethoxysilane and mixed solution was 0.05 g:4 mL:60 mL:15 mL:1.2 mL:15 mL; The ferroferric oxide nanoparticles are ferroferric oxide from Zhongke Keyou, with a specification of 50-300nm; Step A2: Precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, and 1,4-dioxane were mixed and ultrasonically dispersed for 15 minutes. Under nitrogen protection, a stirring rate of 200 rpm, and a temperature of 65°C, azobisisobutyronitrile was added with stirring, and the reaction was carried out for 10 hours. N-isopropylacrylamide was then added and the reaction was continued for 6 hours. Acrylamide was then added and the reaction was continued for 6 hours. The mixture was separated by magnetic attraction, washed, and dried to obtain Precursor 2. The amount ratio of precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, 1,4-dioxane, azobisisobutyronitrile, N-isopropylacrylamide and acrylamide is 0.1g:0.01g:60mL:0.022g:0.06g:0.04g; Step A3: Precursor 2 and deionized water were mixed and ultrasonically dispersed for 20 minutes. Under the conditions of stirring rate of 120 rpm and temperature at room temperature, hydrofluoric acid was added and stirred for 18 minutes. The mixture was separated by magnetic attraction, washed, and dried to obtain magnetic thermosensitive composite microspheres. The mass fraction of hydrofluoric acid is 30%, and the ratio of precursor 2, deionized water, and hydrofluoric acid is 0.08 g:60 mL:0.3 mL; The polyionic liquid is prepared by the following steps: Step B1: β-D-glucose pentaacetate, 3-bromopropanol, and dichloromethane were mixed, stirred at a stirring rate of 140 rpm and room temperature, and boron trifluoride ether was added for reaction for 12 hours. Dichloromethane / water was added for extraction, washed, and rotary evaporated to obtain bromopropylated glucose pentaacetate. Bromopropylated glucose pentaacetate and methanol were mixed, stirred at a stirring rate of 120 rpm and a temperature of 2° C., and sodium methoxide solution was added for reaction for 4 hours. The mixture was freeze-dried and washed to obtain bromopropylated glucose. The dosage ratio of β-D-glucose pentaacetate, 3-bromopropanol, dichloromethane, and boron trifluoride etherate is 0.51 g:1 g:3 mL:0.8 mL; the molar concentration of the sodium methoxide solution is 0.01 mol / L, and the dosage ratio of bromopropylated glucose pentaacetate, methanol, and sodium methoxide solution is 0.28 g:8 mL:0.5 mL; Step B2: Bromopropylated glucose, N-vinylimidazole, and acetonitrile were mixed, stirred at 120 rpm, and 75° C. under nitrogen protection, reacted for 10 h, rotary evaporated, washed, and dried to obtain quaternized glucose. Quaternized glucose, divinylbenzene, azobisisobutyronitrile, and N, N-dimethylformamide were mixed, stirred at 120 rpm, and 75° C. under nitrogen protection, reacted for 20 h, filtered, washed, and vacuum dried to obtain a polyionic liquid. The usage ratio of bromopropylated glucose, N-vinylimidazole and acetonitrile is 0.32 g:0.14 g:20 mL; the usage ratio of quaternized glucose, divinylbenzene, azobisisobutyronitrile and N, N-dimethylformamide is 0.45 g:0.95 g:0.08 mL:20 mL.

[0014] Example 3 A method for preparing a flocculant composition for petroleum refinery wastewater comprises the following steps: weighing the following raw materials in parts by weight: 6 parts of magnetic temperature-sensitive composite microspheres, 30 parts of polyionic liquid, and 4 parts of polyaluminum ferric chloride; mixing the magnetic temperature-sensitive composite microspheres, polyionic liquid, and polyaluminum ferric chloride to prepare a flocculant composition for petroleum refinery wastewater; The polyaluminium ferric chloride is Chengda PAFC, with a specification of 80 mesh; The magnetic temperature-sensitive composite microspheres are prepared by the following steps: Step A1: Fe3O4 nanoparticles, an ammonia solution, ethanol, and deionized water were mixed and ultrasonically dispersed for 20 minutes. Tetraethoxysilane was added with stirring at a stirring rate of 140 rpm at room temperature and the mixture was reacted for 3.5 hours. A mixed solution of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane, and ethanol was then added and the mixture was heated to 30°C and reacted for 14 hours. The mixture was then magnetically separated, washed, and dried to obtain Precursor 1. The mass fraction of ammonia solution was 25%, the volume ratio of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane and ethanol in the mixed solution was 0.1:1:10, and the amount ratio of ferrosoferric oxide nanoparticles, ammonia solution, ethanol, deionized water, tetraethoxysilane and mixed solution was 0.08 g:4 mL:70 mL:15 mL:1.5 mL:15 mL; The ferroferric oxide nanoparticles are ferroferric oxide from Zhongke Keyou, with a specification of 50-300nm; Step A2: Precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, and 1,4-dioxane were mixed and ultrasonically dispersed for 20 minutes. Under nitrogen protection, a stirring rate of 200 rpm, and a temperature of 65°C, azobisisobutyronitrile was added with stirring, and the reaction was carried out for 12 hours. N-isopropylacrylamide was then added and the reaction was continued for 6 hours. Acrylamide was then added and the reaction was continued for 8 hours. The mixture was separated by magnetic attraction, washed, and dried to obtain Precursor 2. The amount ratio of precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, 1,4-dioxane, azobisisobutyronitrile, N-isopropylacrylamide and acrylamide is 0.1g:0.012g:60mL:0.022g:0.07g:0.05g; Step A3: Precursor 2 and deionized water were mixed and ultrasonically dispersed for 20 minutes. Under the conditions of stirring rate of 180 rpm and temperature at room temperature, hydrofluoric acid was added and stirred for 18 minutes. The mixture was separated by magnetic attraction, washed, and dried to obtain magnetic thermosensitive composite microspheres. The mass fraction of hydrofluoric acid is 30%, and the ratio of precursor 2, deionized water, and hydrofluoric acid is 0.1 g:60 mL:0.3 mL; The polyionic liquid is prepared by the following steps: Step B1: β-D-glucose pentaacetate, 3-bromopropanol, and dichloromethane were mixed, stirred at a stirring rate of 160 rpm and room temperature, and boron trifluoride ether was added, and the mixture was reacted for 12 hours. Dichloromethane / water was added for extraction, washed, and rotary evaporated to obtain bromopropylated glucose pentaacetate. Bromopropylated glucose pentaacetate and methanol were mixed, stirred at a stirring rate of 140 rpm and a temperature of 5°C, and sodium methoxide solution was added, and the mixture was reacted for 5 hours. The mixture was freeze-dried and washed to obtain bromopropylated glucose. The dosage ratio of β-D-glucose pentaacetate, 3-bromopropanol, dichloromethane, and boron trifluoride etherate is 0.52 g:1.05 g:5 mL:1 mL; the molar concentration of the sodium methoxide solution is 0.01 mol / L, and the dosage ratio of bromopropylated glucose pentaacetate, methanol, and sodium methoxide solution is 0.3 g:10 mL:0.6 mL; Step B2: Bromopropylated glucose, N-vinylimidazole, and acetonitrile were mixed, stirred at 180 rpm, and 75° C. under nitrogen protection for 12 h, rotary evaporated, washed, and dried to obtain quaternized glucose. Quaternized glucose, divinylbenzene, azobisisobutyronitrile, and N, N-dimethylformamide were mixed, stirred at 180 rpm, and 75° C. under nitrogen protection for 24 h, filtered, washed, and vacuum dried to obtain a polyionic liquid. The usage ratio of bromopropylated glucose, N-vinylimidazole and acetonitrile is 0.35 g:0.16 g:25 mL; the usage ratio of quaternized glucose, divinylbenzene, azobisisobutyronitrile and N, N-dimethylformamide is 0.48 g:1 g:0.1 mL:25 mL.

[0015] Comparative Example 1 Compared with Example 3, this comparative example removes N-isopropylacrylamide during the preparation of magnetic thermosensitive composite microspheres in Example 3, and the other steps are the same.

[0016] Comparative Example 2 Compared with Example 3, this comparative example is different in that the quaternized glucose in the preparation process of the polyionic liquid in Example 3 is replaced by 1-vinyl-3-butylimidazolium bromide, and the other steps are the same.

[0017] The flocculant compositions for petroleum refinery wastewater prepared in Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2 were tested on the petroleum refinery wastewater. The light transmittance was 38.7%, the oil content was 1237 mg / L, the COD concentration was 3556 mg / L, the SS concentration was 471 mg / L, and the turbidity was 373 NTU. The flocculant compositions were added to the petroleum refinery wastewater at a concentration of 200 mg / L. The mixture was stirred for 10 minutes at a pH of 7.5, a stirring rate of 240 rpm, and a temperature of 35°C. The light transmittance was tested. The flocculant compositions were adsorbed by a magnet and recovered at a temperature of 15°C to 35°C. This was repeated five times. The light transmittance was then tested. The test results are shown in the following table: Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Light transmittance (%) 81.16 81.72 82.41 81.35 70.15 Transmittance after recycling (%) 77.23 77.40 78.31 65.50 62.91 It can be seen from the test results in the table shown that when Example 1, Example 2 and Example 3 are compared with Comparative Example 1 and Comparative Example 2, Comparative Example 1 removes N-isopropylacrylamide in the preparation process of the magnetic thermosensitive composite microspheres in Example 3. Due to the lack of a thermosensitive response structure, the flocculation effect decreases after the recycling process; Comparative Example 2 replaces the quaternized ammonium glucose in the preparation process of the polyionic liquid in Example 3 with 1-vinyl-3-butylimidazolium bromide. Due to the lack of a glucose unit, it is unable to demulsify and flocculate well, thereby reducing its flocculation effect.

[0018] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0019] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the concept of the invention, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a flocculant composition for petroleum refining wastewater, characterized in that: The method comprises the following steps: weighing the following raw materials in parts by weight: 5-6 parts of magnetic temperature-sensitive composite microspheres, 25-30 parts of polyionic liquid and 3.5-4 parts of polyaluminum ferric chloride; mixing the magnetic temperature-sensitive composite microspheres, polyionic liquid and polyaluminum ferric chloride to prepare a flocculant composition for petroleum refining wastewater.

2. The method for preparing a flocculant composition for petroleum refining wastewater according to claim 1, characterized in that: The magnetic temperature-sensitive composite microspheres are prepared by the following steps: Step A1: Fe3O4 nanoparticles, an ammonia solution, ethanol, and deionized water were mixed and ultrasonically dispersed for 15-20 minutes. Tetraethoxysilane was added with stirring at a stirring rate of 120-140 rpm at room temperature, and the mixture was reacted for 3-3.5 hours. A mixed solution of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane, and ethanol was then added, and the mixture was heated to 30°C and reacted for 12-14 hours. The mixture was then magnetically separated, washed, and dried to obtain Precursor 1. Step A2: Precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, and 1,4-dioxane were mixed and ultrasonically dispersed for 15-20 minutes. Under nitrogen protection, a stirring rate of 180-200 rpm, and a temperature of 65°C, azobisisobutyronitrile was added with stirring, and the reaction was carried out for 10-12 hours. N-isopropylacrylamide was then added and the reaction was continued for 5-6 hours. Acrylamide was then added and the reaction was continued for 6-8 hours. The mixture was separated by magnetic attraction, washed, and dried to obtain Precursor 2. Step A3: Precursor 2 and deionized water were mixed and ultrasonically dispersed for 15-20 minutes. At a stirring rate of 120-180 rpm and room temperature, hydrofluoric acid was added and stirred for 15-18 minutes. The mixture was separated by magnetic attraction, washed, and dried to obtain magnetic thermosensitive composite microspheres.

3. The method for preparing a flocculant composition for petroleum refining wastewater according to claim 2, characterized in that: In step A1: the mass fraction of the ammonia solution is 25%, the volume ratio of tetraethoxysilane, 3-(isomethacryloyloxy)propyltrimethoxysilane and ethanol in the mixed solution is 0.1:1:10, and the amount ratio of ferrosoferric oxide nanoparticles, ammonia solution, ethanol, deionized water, tetraethoxysilane and mixed solution is 0.05-0.08 g:3.5-4 mL:60-70 mL:10-15 mL:1.2-1.5 mL:12-15 mL.

4. The method for preparing a flocculant composition for petroleum refining wastewater according to claim 2, characterized in that: In step A2: the amount ratio of precursor 1, 2-cyano-2-propyl dodecyl trithiocarbonate, 1,4-dioxane, azobisisobutyronitrile, N-isopropylacrylamide and acrylamide is 0.08-0.1g: 0.01-0.012g: 60mL: 0.02-0.022g: 0.06-0.07g: 0.04-0.05g.

5. The method for preparing a flocculant composition for petroleum refining wastewater according to claim 2, characterized in that: In step A3: the mass fraction of hydrofluoric acid is 30%, and the ratio of precursor 2, deionized water and hydrofluoric acid is 0.08-0.1 g: 50-60 mL: 0.2-0.3 mL.

6. The method for preparing a flocculant composition for petroleum refining wastewater according to claim 1, characterized in that: The polyionic liquid is prepared by the following steps: Step B1: β-D-glucose pentaacetate, 3-bromopropanol and dichloromethane are mixed, stirred at a stirring rate of 140-160 rpm and room temperature, and boron trifluoride etherate is added, and the reaction is carried out for 12 hours. Dichloromethane / water is added for extraction, washing, and rotary evaporation to obtain bromopropylated glucose pentaacetate. Bromopropylated glucose pentaacetate and methanol are mixed, stirred at a stirring rate of 120-140 rpm and a temperature of 2-5°C, and sodium methoxide solution is added, and the reaction is carried out for 4-5 hours. The mixture is freeze-dried and washed to obtain bromopropylated glucose; Step B2: Bromopropylated glucose, N-vinylimidazole and acetonitrile are mixed, and the mixture is stirred at a rate of 120-180 rpm and a temperature of 75°C under nitrogen protection for 10-12 hours. The mixture is rotary evaporated, washed, and dried to obtain quaternized glucose. Quaternized glucose, divinylbenzene, azobisisobutyronitrile and N, N-dimethylformamide are mixed, and the mixture is stirred at a rate of 120-180 rpm and a temperature of 75°C under nitrogen protection for 20-24 hours. The mixture is filtered, washed, and vacuum dried to obtain a polyionic liquid.

7. The method for preparing a flocculant composition for petroleum refinery wastewater according to claim 6, characterized in that: In step B1, the amount ratio of β-D-glucose pentaacetate, 3-bromopropanol, dichloromethane and boron trifluoride etherate is 0.51-0.52 g: 1-1.05 g: 3-5 mL: 0.8-1 mL; the molar concentration of the sodium methoxide solution is 0.01 mol / L, and the amount ratio of bromopropylated glucose pentaacetate, methanol and sodium methoxide solution is 0.28-0.3 g: 8-10 mL: 0.5-0.6 mL.

8. The method for preparing a flocculant composition for petroleum refining wastewater according to claim 6, characterized in that: In step B2, the ratio of bromopropylated glucose, N-vinylimidazole, and acetonitrile is 0.32-0.35 g: 0.14-0.16 g: 20-25 mL; the ratio of quaternized glucose, divinylbenzene, azobisisobutyronitrile, and N, N-dimethylformamide is 0.45-0.48 g: 0.95-1 g: 0.08-0.1 mL: 20-25 mL.

9. A flocculant composition for petroleum refining wastewater, characterized in that: Prepared according to any one of claims 1 to 8.