Efficient oil-removing water purifying agent and preparation method thereof

Abstract

The invention provides an efficient oil-removing water purifying agent and a preparation method thereof. The oil-removing water purifying agent mainly comprises a micro-crosslinking multi-branched cationic copolymer, fatty acid methyl ester ethoxylate, dodecyl dimethyl benzyl ammonium chloride and deionized water. The micro-crosslinked multi-branched cationic copolymer is mainly prepared from a non-polar solvent, a branched monomer, a crosslinking monomer, acrylamide, a cationic monomer, an emulsifier, an initiator, an organic solvent and deionized water, and the fatty acid methyl ester ethoxylate is mainly prepared from methyl stearate, a catalyst, ethylene oxide, isopropanol and deionized water. The efficient oil-removing water purifying agent mainly aims at the defects of an existing oil-removing water purifying agent, the micro-crosslinking multi-branched cationic copolymer is used as a flocculating agent, the fatty acid methyl ester ethoxylate is used as a nonionic surfactant, and through the synergistic effect of the micro-crosslinking multi-branched cationic copolymer and the fatty acid methyl ester ethoxylate, the efficient oil-removing water purifying agent is obtained. Therefore, the prepared oil-removing water purifying agent has better oil-removing effect and dispersing performance.

Description

Technical Field

[0001] The invention belongs to the technical field of oily wastewater treatment, and in particular relates to a high-efficiency oil-removing water purifier and a preparation method thereof. Background Art

[0002] In recent years, with the further development of industrialization, various industries such as oil refining, steel, food, textile and leather have generated a large amount of oily wastewater. Pollution parameters vary from industry to industry and production, forming wastewater with different characteristics. According to statistics, oily wastewater generated by refineries alone in my country is as high as 550 million tons per year, and less than 50% of them meet the treatment standards. Oily wastewater contains suspended particles, dissolved salts, dissolved or insoluble organic matter, and these non-biodegradable pollutants will cause great trouble to the water treatment process. The use of polymer flooding in many oil fields has made the oil field wastewater complex, stable, high in oil content, poor in biodegradability, and volatile, which brings great challenges to the treatment of oily wastewater. The current methods used to treat oily wastewater include solvent extraction, electrocoagulation, membrane separation, biotechnology, flotation, adsorption, cyclone separation, flocculation, etc. Among them, the solvent extraction method requires high energy input during solvent recovery and distillation, and the solvent volatilizes greatly; the electrocoagulation method requires high electrical energy, has large electrode losses, and will produce pollutants such as chlorinated organic matter and sludge; the biotechnology has low efficiency in treating oily wastewater; membrane fouling in membrane separation will limit its separation efficiency; the limitations of flotation technology include low efficiency, high energy demand, low oil selectivity, and a long time required to achieve the expected separation efficiency; the adsorption method has low separation efficiency for fine oil particles, high cost of oil absorbents, and low efficiency at high oil concentrations; the cyclone separation method requires high energy, has low separation efficiency for oil particles, and has high maintenance costs; and flocculation has the characteristics of simple operation, environmental friendliness, low cost, and stable effects, and is currently widely used in the treatment of oily wastewater.

[0003] At present, the most commonly used oil removal and water purification agent for the treatment of oily wastewater in oil fields is cationic polyacrylamide flocculant. When treating oily wastewater, this type of flocculant has the following problems: low polymer molecular weight, weak adsorption bridging effect, high molecular weight, poor water solubility; random distribution of cations on the molecular chain, uneven distribution of charge density, low utilization rate of cationic charge; weak interaction between flocculants and wastewater particles, etc.

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

[0005] The first purpose of the present invention is to provide a high-efficiency oil-removing and water-purifying agent. The oil-removing and water-purifying agent adopts a micro-crosslinked multi-branched cationic copolymer as a flocculant and a fatty acid methyl ester ethoxylate as a non-ionic surfactant. The two are compatible and work together, so that the prepared oil-removing and water-purifying agent has the characteristics of fast oil-water separation, short flocculation time, and better oil-removing and water-purifying effect.

[0006] The second object of the present invention is to provide a method for preparing an efficient oil-removing and water-purifying agent, which has simple operation, mild operating conditions, easily controllable reaction conditions and stable synthesis process.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: The invention provides a high-efficiency oil-removing and water-purifying agent, which mainly comprises a micro-crosslinked multi-branched cationic copolymer, fatty acid methyl ester ethoxylate, dodecyl dimethyl benzyl ammonium chloride and deionized water; The micro-crosslinked multi-branched cationic copolymer is mainly prepared from a non-polar solvent, a branching monomer, a crosslinking monomer, acrylamide, a cationic monomer, an emulsifier, an initiator, an organic solvent and deionized water, wherein the molar ratio of acrylamide to the cationic monomer is (1-1.5):1; The fatty acid methyl ester ethoxylate is mainly prepared from methyl stearate, a catalyst, ethylene oxide, isopropanol and deionized water, wherein the mass ratio of the catalyst to the methyl stearate is (0.005-0.015):1, and the mass ratio of the ethylene oxide to the methyl stearate is (0.5-1):1.

[0008] In the high-efficiency oil-removing and water-purifying agent of the present invention, it mainly adopts branched monomers, cross-linked monomers, cationic monomers and acrylamide to react with each other under specific conditions to generate long-chain polymers, and multiple substances share atoms or chemical bonds to connect monomer molecules in an orderly manner, thereby forming a micro-cross-linked multi-branched cationic copolymer with high molecular weight and continuous structure. The micro-cross-linked multi-branched cationic copolymer is used as a flocculant in the oil-removing and water-purifying agent to achieve better flocculation effect and faster separation speed. Among them, the selection of branched monomers, cross-linked monomers and cationic monomers is very important for the present invention, because only when suitable monomers are selected can the The obtained copolymer has a suitable physical structure, so that the performance of the polymer is excellent. When the branching monomer is trimethylolpropane triacrylate, the cross-linking monomer is 3-carboxypropyltrimethoxysilane, and the cationic monomer is acryloyloxyethyl dimethylbenzyl ammonium chloride, the prepared micro-cross-linked multi-branched cationic copolymer has excellent effect. This is because trimethylolpropane triacrylate is a commonly used hydrophobic branching monomer, which has the characteristics of strong hydrophobic performance, and as a hydrophobic monomer, it can be introduced into the reaction system to form a copolymer to enhance the hydrophobic association effect, so that the prepared flocculant can better accelerate the separation speed between oil flocs and water, so that the flocculation effect of the oil removal and water purification agent is better. , and because trimethylolpropane triacrylate monomer has more chemical bonds, the three double bonds it contains can be better polymerized with other monomer substances, and this structure can be more stretched due to the electrostatic repulsion of the cationic group and the steric hindrance factor, so that the curling and entanglement between ordinary molecular chains are reduced, the overall conformation is more stretched, and the fluid mechanics volume is larger. This structure can greatly improve the utilization rate of cationic charges, enhance the electrical neutralization ability, and enhance the adsorption bridging effect, so that the molecular chain produced by the copolymerization reaction has more cationic adsorption sites, effectively neutralizes the surface charge of the particles, and then promotes the flocculation process and accelerates the flocculation rate of the oil removal and water purifier. And because of the three The hydroxymethylpropane triacrylate monomer has more chemical bonds, so that the trimethylolpropane triacrylate monomer can have a better copolymerization reaction with other monomer substances, so that more monomer substances can be connected to the trimethylolpropane triacrylate monomer, so that more monomer molecules can be connected in order to form a copolymer with a higher molecular weight, greatly improving the flocculation effect of the oil removal and water purification agent; and the 3-carboxypropyltrimethoxysilane can connect multiple monomer molecules well during the polymerization process through micro-crosslinking, so that each monomer molecule can be better connected together to form a stable three-dimensional network structure, thereby increasing the molecular weight of the polymer, enhancing the adsorption bridging effect, improving the quality of the flocculant, and ensuring the flocculation effect.

[0009] Therefore, it can be known from the above description that the molar ratio between acrylamide and the cationic monomer is very important. This is because in the preparation process of the present invention, the cationic monomer and acrylamide are mainly polymerized, so that the cationic monomer and acrylamide can be arranged in order to form a long-chain polymer. The molar ratio of acrylamide is crucial to the present invention. When the molar ratio of acrylamide to the cationic monomer is (1-1.5):1, preferably when the molar ratio of acrylamide to the cationic monomer is 1.5:1, the oil removal and water purification agent prepared therefrom has excellent effect. This is because if the molar ratio of acrylamide to the cationic monomer is too large, acrylamide will undergo homopolymerization reaction, thereby generating by-products, thereby affecting the yield of the micro-crosslinked multi-branched cationic copolymer, making the yield of the micro-crosslinked multi-branched cationic copolymer too low and affecting the flocculation effect; and if the molar ratio of acrylamide to the cationic monomer is too small, the cationic monomer and acrylamide will not be fully polymerized, thereby affecting the yield and molecular weight of the micro-crosslinked multi-branched cationic copolymer and affecting the flocculation effect of the oil removal and water purification agent.

[0010] Preferably, as a further specific implementation, the molar ratio of acrylamide to cationic monomer is 1.5:1.

[0011] Preferably, as a further specific embodiment, the mass ratio of the catalyst to the methyl stearate is 0.0125:1; The mass ratio of the ethylene oxide to the methyl stearate is 0.65:1.

[0012] In the present invention, fatty acid methyl ester ethoxylate is used as a nonionic surfactant, so that the oil removal water purifier prepared has low foam, high cloud point, cold water is not easy to gel, dissolves quickly and has better oil removal dispersion effect, wherein the mass ratio of ethylene oxide and methyl stearate in the fatty acid methyl ester ethoxylate of the present invention is very important, because the application scene environment of the oil removal water purifier provided by the present invention is harsh, and the temperature is low, and the oil removal water purifier prepared by the traditional surfactant has poor flowability at low temperature, low cloud point, and is easy to condense under cold water, so that the oil removal dispersion effect of the oil removal water purifier is poor, and fatty acid methyl ester ethoxylate is a nonionic surfactant, which is obtained by direct addition reaction of methyl stearate and ethylene oxide under the action of a catalyst, and compared with traditional fatty alcohol ethoxylates, fatty acid methyl ester ethoxylates show significant differences. First, its foam generation ability is low, which means that the surface can be better kept clean during use. In addition, fatty acid methyl ester ethoxylate has a high cloud point, which means that it can still maintain good fluidity in a low temperature environment and can easily cope with various application conditions even in winter. Moreover, fatty acid methyl ester ethoxylate dissolves very quickly in cold water, thereby greatly improving its convenience of use, so that the prepared oil removal and water purification agent can be quickly and evenly dispersed in water without an additional heating step, and has excellent performance in removing grease and dirt. In the oil removal and water purification agent of the present invention, only when the mass ratio of ethylene oxide to methyl stearate is in an appropriate range, the yield of the prepared fatty acid methyl ester ethoxylate is high, and it can well cooperate with the micro-crosslinked multi-branched cationic copolymer. A better oil removal and flocculation effect is achieved, wherein in the preparation process of fatty acid methyl ester ethoxylate, the mass ratio of the catalyst to methyl stearate and the mass ratio of ethylene oxide to methyl stearate are very important for the present invention. When the mass ratio of the catalyst to methyl stearate is (0.005-0.015):1 and the mass ratio of ethylene oxide to methyl stearate is (0.5-1):1, preferably when the mass ratio of the catalyst to methyl stearate is 0.0125:1 and the mass ratio of ethylene oxide to methyl stearate is 0.65:1, the fatty acid methyl ester ethoxylate prepared by the method has a high yield and can cooperate well with the micro-crosslinked multi-branched cationic copolymer to achieve a better oil removal and flocculation effect.

[0013] Preferably, as a further specific embodiment, the non-polar solvent is one or more of methyl silicone oil, liquid paraffin and kerosene; The organic solvent is any one of anhydrous ethanol and acetone.

[0014] In the present invention, more micro-crosslinked multi-branched cationic copolymers are prepared by using non-polar solvents, wherein the non-polar solvent is one or more of methyl silicone oil, liquid paraffin and kerosene. Preferably, when the non-polar solvent is methyl silicone oil, the prepared oil removal and water purification agent has excellent effect. This is because in the present invention, the solubility of branched monomers and crosslinked monomers is increased mainly by using non-polar solvents, so that the branched monomers and crosslinked monomers can be more dissolved in the solution, thereby preparing more micro-crosslinked multi-branched cationic copolymers, and better improving the sewage treatment effect of the oil removal and water purification agent. When methyl silicone oil is used as a non-polar solvent to dissolve the branched monomers and crosslinked monomers, the solubility of the branched monomers and the crosslinked monomers is higher.

[0015] Preferably, as a further specific embodiment, the branching monomer is trimethylolpropane triacrylate; The cross-linking monomer is 3-carboxypropyltrimethoxysilane; The cationic monomer is acryloyloxyethyl dimethylbenzyl ammonium chloride; The emulsifier is OP-10; The initiator is potassium sulfate-urea solution or azobisisobutyronitrile.

[0016] Preferably, as a further specific embodiment, the catalyst is magnesium oxide-aluminum oxide.

[0017] The present invention also provides a method for preparing the above-mentioned high-efficiency oil removal and water purification agent, comprising the following steps: preparing micro-crosslinked multi-branched cationic copolymers and fatty acid methyl ester ethoxylates respectively; Take deionized water, add fatty acid methyl ester ethoxylate and slightly cross-linked multi-branched cationic copolymer in sequence, and stir for 60-90 minutes to obtain a mixture; Take deionized water, add dodecyl dimethyl benzyl ammonium chloride to it, stir for 10-15 minutes, then slowly pour into the mixture, stir for 20-30 minutes, and obtain; The step of preparing the slightly cross-linked multi-branched cationic copolymer comprises adding a non-polar solvent, stirring, sequentially adding a branching monomer and a cross-linking monomer, and stirring sufficiently to obtain an oil phase for use; Take deionized water, add acrylamide, cationic monomer and emulsifier into it in sequence while stirring, and stir evenly to obtain a water phase; Slowly add the water phase to the oil phase under rapid stirring to obtain an inverse emulsion; Then, the initiator is added under nitrogen atmosphere at controlled temperature, cooled and stirred, an organic solvent is added, filtered, washed and dried to obtain the product; The steps of preparing fatty acid methyl ester ethoxylate are to add methyl stearate and a catalyst in sequence, then add ethylene oxide under a nitrogen atmosphere, add deionized water and isopropanol after cooling, and stir evenly to obtain the fatty acid methyl ester ethoxylate.

[0018] In the preparation method of the micro-crosslinked multi-branched cationic copolymer of the present invention, temperature control is required when the initiator is added dropwise. If the temperature is too high and the rotation speed is too fast when the initiator is added dropwise, the micro-crosslinked multi-branched cationic copolymer will have side reactions during the preparation process, thereby affecting the yield of the micro-crosslinked multi-branched cationic copolymer. When the temperature is set to 30-50°C, the dropping time is 1-2h, and the rotation speed is 50-70rpm when the initiator is added dropwise, the yield of the micro-crosslinked multi-branched cationic copolymer prepared is high; and after the initiator is added dropwise, the temperature needs to be increased again to facilitate the continued reaction. After the addition is completed, the temperature needs to be raised to 60-80°C and the reaction is continued for 4-5h, so that the yield of the prepared micro-crosslinked multi-branched cationic copolymer is higher while avoiding side reactions.

[0019] In the preparation method of the micro-crosslinked multi-branched cationic copolymer of the present invention, by dripping an initiator and controlling the reaction conditions during the dripping of the initiator, polymerization between multiple monomers can be better initiated. If the temperature is too high when the initiator is dripped, side reactions will occur during the polymerization of the substances due to the high reaction temperature, resulting in many by-products, thereby reducing the flocculation effect of the micro-crosslinked multi-branched cationic copolymer; if the temperature is too low, the polymerization reaction between the multiple monomer substances will be insufficient, resulting in too low a yield of the micro-crosslinked multi-branched cationic copolymer.

[0020] In the preparation process of the fatty acid methyl ester ethoxylate of the present invention, when introducing ethylene oxide, the feeding conditions need to be adjusted to the temperature: 120° C., the rotation speed is 50 rpm, and the feeding is carried out under the condition of heating to 150° C., the rotation speed is 50 rpm, and the pressure is 0.3-0.4 MPa for 4.5 hours after the introduction is completed, so that the reaction is more complete and thorough; and in the subsequent mixing of the water phase and the oil phase, an emulsifier is also added to promote the contact exchange between the two phases.

[0021] Preferably, as a further specific embodiment, the amount of the branching monomer is 0.5-2% of the total amount of the branching monomer, the cross-linking monomer and the cationic monomer; The amount of the cross-linking monomer is 0.05-1% of the total amount of the branching monomer, the cross-linking monomer and the cationic monomer; The amount of the initiator used is 0.05-0.5% of the total amount of the branching monomer, the crosslinking monomer and the cationic monomer.

[0022] In the present invention, the amount of branching monomer, cross-linking monomer and initiator is very important for the present invention. This is because these materials are used as substrates of micro-cross-linked multi-branched cationic copolymers, and their most basic concentrations will affect the progress of the reaction to a certain extent. The increase in concentration within a certain range is conducive to the synthesis of micro-cross-linked multi-branched cationic copolymers, but as the substrate concentration increases, its ability to promote the reaction gradually tends to be stable, and then as the substrate concentration increases, it will trigger a series of side reactions, thereby affecting the yield of the micro-cross-linked multi-branched cationic copolymer. Only when the amount of branching monomer, cross-linking monomer and initiator is within a suitable range, the micro-cross-linked multi-branched cationic copolymer prepared therefrom has a high yield and weak by-products, and the by-products produced are less.

[0023] Preferably, as a further specific implementation, the volume ratio of the oil phase to the water phase is 1:3.

[0024] In the preparation method of the oil-removing water purifier in the present invention, the reverse emulsion polymerization method is mainly adopted, so that the water-soluble dispersed monomer is dispersed in the continuous oil phase with the help of the emulsifier to form a certain oil-in-water emulsion for polymerization reaction. Therefore, the volume ratio of the oil phase and the water phase is very important for the present invention. When the volume ratio of the oil phase to the water phase is 1:3, the oil-removing water purifier prepared is excellent. If there is too much oil phase, since the oil is used as the continuous phase to disperse the droplets, the nucleation mechanism is homogeneous nucleation and micelle nucleation, and too much oil phase will make the water-soluble dispersed monomer unable to be evenly dispersed in the oil phase, thereby affecting the polymerization reaction.

[0025] Preferably, as a further specific implementation, the temperature control conditions are as follows: temperature is 30-50°C, dropwise addition time is 1-2h, and rotation speed is 50-70rpm.

[0026] In the present invention, the temperature control condition is very important when the initiator is added dropwise. When the temperature control condition is 30-50°C, the dropping time is 1-2h, and the rotation speed is 50-70rpm, the polymerization reaction can be better carried out between the monomers under the initiation of the initiator, so that the yield of the slightly cross-linked multi-branched cationic copolymer is higher. When the water phase and the oil phase are mixed, the water-soluble monomers are dispersed in the oil phase under the action of the emulsifier to form an oil-in-water emulsion for polymerization, which is an exothermic reaction. Therefore, when the initiator is added dropwise, the dropping is too fast and may release heat violently, affecting the polymerization effect.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a highly efficient oil-removing and water-purifying agent, which adopts a micro-crosslinked multi-branched cationic copolymer as a flocculant and a fatty acid methyl ester ethoxylate as a non-ionic surfactant. The two interact with each other to make the prepared oil-removing and water-purifying agent have the characteristics of fast oil-water separation, short flocculation time and better oil-removing and water-purifying effect.

[0028] (2) The present invention provides a method for preparing a highly efficient oil-removing water purifier, which has simple operation, mild operating conditions, easily controllable reaction conditions and a stable synthesis process. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with specific implementation methods, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments, 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.

[0030] In order to more clearly explain the technical solution of the present invention, it is described in the form of specific embodiments below.

[0031] Example 1 The specific preparation process of the high-efficiency oil removal and water purification agent of the present invention is: (1) Preparation of micro-crosslinked multi-branched cationic copolymers The amount of branching monomer used is 0.5% of the total amount of branching monomer, crosslinking monomer and cationic monomer; The amount of crosslinking monomer used is 0.05% of the total amount of branching monomer, crosslinking monomer and cationic monomer; The amount of initiator used is 0.05% of the total amount of branching monomers, crosslinking monomers and cationic monomers; Step 1: Prepare the oil phase. Add methyl silicone oil to the reaction bottle, start mechanical stirring at 100 rpm, then add a certain amount of trimethylolpropane triacrylate and 3-carboxypropyltrimethoxysilane in sequence, stir thoroughly to dissolve them to obtain the oil phase; Step 2: Prepare the aqueous phase. Add a certain amount of deionized water to a beaker, start mechanical stirring at 100 rpm, and then add acrylamide, acryloyloxyethyl dimethyl benzyl ammonium chloride and OP-10 in a molar ratio of 1:1 to prepare a monomer solution with a mass concentration of 30%, stir until completely dissolved, and transfer the aqueous phase to a constant pressure dropping funnel for use; Step 3: Prepare the inverse emulsion. Under rapid stirring at a speed of 100 rpm, slowly drop the water phase into the oil phase and stir for a certain period of time. At this time, the volume ratio of the oil phase to the water phase is 1:3, and a stable inverse emulsion is obtained; Step 4: Synthesis of copolymer. The reaction flask was equipped with a thermometer, a condenser (water-cooled), and a glass gas guide tube, and nitrogen was passed for 1 hour to evacuate the air in the reaction flask, and nitrogen was continuously passed for protection of subsequent reactions. The temperature was controlled at 30°C, and the potassium sulfate-urea solution was slowly added dropwise at a speed of 50 rpm for 1 hour. After the addition was completed, the temperature was raised to 60°C, and the reaction was continued at a speed of 50 rpm for 4 hours. After the reaction was completed, it was cooled to room temperature, anhydrous ethanol was added under stirring conditions, and the mixture was filtered, washed with anhydrous ethanol, and dried to obtain a slightly cross-linked multi-branched cationic copolymer.

[0032] (2) Preparation of fatty acid methyl ester ethoxylate Methyl stearate is used as an initiator, magnesium oxide-alumina is added according to a feeding ratio of magnesium oxide-alumina and methyl stearate of 0.005:1, and the air in the reactor is emptied by nitrogen. Subsequently, ethylene oxide is introduced into the reactor according to a mass ratio of ethylene oxide to methyl stearate of 0.5:1 under the feeding conditions of a temperature of 120° C. and a rotation speed of 50 rpm, and the air in the reactor is evacuated by nitrogen again, and the sealed system is subjected to ethoxylation reaction for 4.5 hours under the reaction conditions of a temperature of 150° C., a rotation speed of 50 rpm, and a reaction pressure of 0.3 MPa; After the reaction is completed, the mixture is aged and cooled to 120°C, and then cooled to 60°C by cooling water. Deionized water and isopropanol are added, stirred evenly, and nitrogen is injected to extract the product.

[0033] (3) Preparation of high-efficiency oil removal and water purification agent Deionized water was taken, and fatty acid methyl ester ethoxylate and slightly cross-linked multi-branched cationic copolymer were added thereto in sequence, and stirred for 60 minutes to obtain a mixture; Take deionized water, add dodecyl dimethyl benzyl ammonium chloride to the deionized water, stir and dissolve for 10 minutes to obtain dodecyl dimethyl benzyl ammonium chloride solution; Add dodecyldimethylbenzylammonium chloride solution into the mixture and continue stirring for 20 minutes to obtain the product.

[0034] Example 2 The specific preparation process of the high-efficiency oil removal and water purification agent of the present invention is: (1) Preparation of micro-crosslinked multi-branched cationic copolymers The amount of the branching monomer is 2% of the total amount of the branching monomer, the cross-linking monomer and the cationic monomer; The amount of crosslinking monomer used is 1% of the total amount of branching monomer, crosslinking monomer and cationic monomer; The amount of initiator used is 0.5% of the total amount of branching monomers, crosslinking monomers and cationic monomers; Step 1: Prepare the oil phase. Add kerosene to the reaction bottle, start the mechanical stirring at 100 rpm, then add a certain amount of trimethylolpropane triacrylate and 3-carboxypropyltrimethoxysilane in sequence, stir thoroughly to dissolve them to obtain the oil phase; Step 2: Prepare the aqueous phase. Add a certain amount of deionized water to a beaker, start mechanical stirring at 100 rpm, and then add acrylamide, acryloxyethyl dimethyl benzyl ammonium chloride and OP-10 in a molar ratio of acrylamide to acryloxyethyl dimethyl benzyl ammonium chloride of 1.5:1 to prepare a monomer solution with a mass concentration of 50%, stir until completely dissolved, and transfer the aqueous phase to a constant pressure dropping funnel for use; Step 3: Prepare the inverse emulsion. Under rapid stirring at a speed of 150 rpm, slowly add the water phase to the oil phase and stir for 35 minutes. At this time, the volume ratio of the oil phase to the water phase is 1:3, and a stable inverse emulsion is obtained; Step 4: Synthesis of copolymer. The reaction bottle was equipped with a thermometer, a condenser (water-cooled), and a glass gas guide tube. Nitrogen was passed for 1 hour to evacuate the air in the reaction bottle, and nitrogen was continuously passed for protection of subsequent reactions. Azobisisobutyronitrile was slowly added dropwise for 2 hours at a temperature of 50°C and a speed of 70 rpm. After the addition, the temperature was raised to 80°C and the reaction was continued at a speed of 70 rpm for 5 hours. After the reaction was completed, the reaction was cooled to room temperature, acetone was added under stirring, and the mixture was filtered, washed with acetone, and dried to obtain a slightly cross-linked multi-branched cationic copolymer.

[0035] (2) Preparation of fatty acid methyl ester ethoxylate Methyl stearate was used as the initiator, and the catalyst was added in a feeding ratio of magnesium oxide-aluminum oxide and methyl stearate of 0.015:1, and the air in the reactor was evacuated by nitrogen. Subsequently, ethylene oxide was introduced into the reactor in a mass ratio of ethylene oxide and methyl stearate of 1:1 under the feeding conditions of temperature of 120° C. and rotation speed of 50 rpm, and the air in the reactor was evacuated by nitrogen again, and the sealed system was subjected to ethoxylation reaction for 4.5 hours under the reaction conditions of temperature of 150° C., rotation speed of 50 rpm, and reaction pressure of 0.4 MPa; After the reaction is completed, the mixture is aged and cooled to 120°C, and then cooled to 60°C by cooling water. Deionized water and isopropanol are added, stirred evenly, and nitrogen is injected to extract the product.

[0036] (3) Preparation of high-efficiency oil removal and water purification agent Deionized water was taken, and fatty acid methyl ester ethoxylate and slightly cross-linked multi-branched cationic copolymer were added thereto in sequence, and stirred for 90 minutes to obtain a mixture; Take deionized water, add dodecyl dimethyl benzyl ammonium chloride to the deionized water, stir and dissolve for 15 minutes to obtain dodecyl dimethyl benzyl ammonium chloride solution; Add dodecyldimethylbenzylammonium chloride solution into the mixture and continue stirring for 30 minutes to obtain the product.

[0037] Example 3 The specific preparation process of the high-efficiency oil removal and water purification agent of the present invention is: (1) Preparation of micro-crosslinked multi-branched cationic copolymers The amount of the branching monomer is 1% of the total amount of the branching monomer, the cross-linking monomer and the cationic monomer; The amount of crosslinking monomer used is 0.5% of the total amount of branching monomer, crosslinking monomer and cationic monomer; The amount of initiator used is 0.5% of the total amount of branching monomers, crosslinking monomers and cationic monomers; Step 1: Prepare the oil phase. Add methyl silicone oil to the reaction bottle, start mechanical stirring at 100 rpm, then add a certain amount of trimethylolpropane triacrylate and 3-carboxypropyltrimethoxysilane in sequence, stir thoroughly to dissolve them to obtain the oil phase; Step 2: Prepare the aqueous phase. Add a certain amount of deionized water to a beaker, start mechanical stirring at 100 rpm, and then add acrylamide, acryloxyethyl dimethyl benzyl ammonium chloride and OP-10 in a molar ratio of acrylamide to acryloxyethyl dimethyl benzyl ammonium chloride of 1.5:1 to prepare a monomer solution with a mass concentration of 30%, stir until completely dissolved, and transfer the aqueous phase to a constant pressure dropping funnel for use; Step 3: Prepare the inverse emulsion. Under rapid stirring at a speed of 100 rpm, slowly drop the water phase into the oil phase and stir for a certain period of time. At this time, the volume ratio of the oil phase to the water phase is 1:3, and a stable inverse emulsion is obtained; Step 4: Synthesis of copolymer. The reaction flask was equipped with a thermometer, a condenser (water-cooled), and a glass gas guide tube, and nitrogen was passed for 1 hour to evacuate the air in the reaction flask, and nitrogen was continuously passed for protection of subsequent reactions. The temperature was controlled at 50°C and potassium sulfate-urea was slowly added dropwise at a speed of 70 rpm for 2 hours. After the addition was completed, the temperature was raised to 80°C and the reaction was continued at a speed of 70 rpm for 5 hours. After the reaction was completed, the reaction was cooled to room temperature, and an organic solvent was added under stirring conditions, and the mixture was filtered, washed with an organic solvent, and dried to obtain a slightly cross-linked multi-branched cationic copolymer.

[0038] (2) Preparation of fatty acid methyl ester ethoxylate Methyl stearate was used as the initiator, magnesium oxide-aluminum oxide was added according to the mass ratio of catalyst to methyl stearate of 0.0125:1, and the air in the reactor was evacuated by nitrogen. Subsequently, ethylene oxide was introduced into the reactor at a mass ratio of ethylene oxide to methyl stearate of 0.65:1 under the conditions of temperature of 120° C. and rotation speed of 50 rpm, and the air in the reactor was evacuated by nitrogen again. The sealed system was subjected to ethoxylation reaction for 4.5 hours under the reaction conditions of temperature of 150° C., rotation speed of 50 rpm, and reaction pressure of 0.3 MPa; After the reaction is completed, the mixture is aged and cooled to 120°C, and then cooled to 60°C by cooling water. Deionized water and isopropanol are added, stirred evenly, and nitrogen is injected to extract the product.

[0039] (3) Preparation of high-efficiency oil removal and water purification agent Deionized water was taken, and fatty acid methyl ester ethoxylate and slightly cross-linked multi-branched cationic copolymer were added thereto in sequence, and stirred for 60 minutes to obtain a mixture; Take deionized water, add dodecyl dimethyl benzyl ammonium chloride to the deionized water, stir and dissolve for 15 minutes to obtain dodecyl dimethyl benzyl ammonium chloride solution; Add dodecyldimethylbenzylammonium chloride solution into the mixture and continue stirring for 20 minutes to obtain the product.

[0040] The oil removal water purifier prepared in Examples 1-3 and the commercially available oil removal water purifier were tested for sewage treatment effects, and the test results are shown in Table 1 below: Table 1 Test results

[0041] Therefore, it can be seen from the above experimental data that the oil removal and water purification agent prepared by the present invention has excellent performance, and its oil removal rate is better than that of commercially available products.

[0042] Experimental Example 1 Effect of material ratio on the preparation of micro-crosslinked multi-branched cationic copolymers The preparation steps of the slightly cross-linked multi-branched cationic copolymer are as follows: Step 1: Prepare the oil phase. Add methyl silicone oil to the reaction bottle, turn on the mechanical stirrer at 100 rpm, and then add a certain amount of trimethylolpropane triacrylate and 3-carboxypropyl trimethoxysilane in sequence, where the specific amounts of trimethylolpropane triacrylate and 3-carboxypropyl trimethoxysilane are shown in Table 2.1 below, and stir thoroughly to dissolve them to obtain the oil phase.

[0043] The second step is to prepare the aqueous phase. Add a certain amount of deionized water to the beaker, start the mechanical stirring at 100 rpm, and then add acrylamide (AM), acryloyloxyethyl dimethylbenzyl ammonium chloride (DBAC) and OP-10 in sequence to prepare a solution with the monomer mass concentration shown in Table 2.3, where the specific amounts of acrylamide (AM), acryloyloxyethyl dimethylbenzyl ammonium chloride (DBAC) and OP-10 are shown in Table 2.1; stir until completely dissolved and transfer the aqueous phase to a constant pressure dropping funnel for use.

[0044] The third step is to prepare an inverse emulsion. The water phase is slowly added dropwise to the oil phase according to the volume ratio shown in Table 2.2 with mechanical stirring at 150 rpm, and the mixture is stirred for 30 minutes to obtain a stable inverse emulsion.

[0045] Step 4: Synthesize copolymers. Equip the reaction flask with a thermometer, a condenser (water-cooled), and a glass gas guide tube, pass nitrogen for 1 hour, exhaust the air in the reaction flask, and continue to pass nitrogen to protect the subsequent reaction. Control the temperature at 30°C, slowly add potassium sulfate-urea solution at 70rpm, and the addition time is 2 hours; after the addition is completed, heat to 80°C, and continue to react at 70rpm for 5 hours. After the reaction is completed, cool to room temperature, add acetone under stirring, filter, wash with acetone, and dry to obtain a slightly cross-linked multi-branched cationic copolymer and calculate the yield. The final result is shown below; Table 2.1 Experimental material ratio and results

[0046] Table 2 .2 Volume ratio of oil phase to water phase and results

[0047] Table 2.3 Effect of monomer mass concentration on results

[0048] Experimental Example 2 Determination of the effect of oil removal and water purification agent on oily wastewater treatment This experimental example measures the effect of the oil removal water purifier obtained in groups 8-15 in Experimental Example 3 on sewage treatment, and the measurement results are shown in Table 3 below: Table 3

[0049] From the above experimental data, it can be known that the molar ratio of acrylamide (AM) and acryloyloxyethyl dimethylbenzyl ammonium chloride, the amount of each monomer, the volume ratio between the water phase and the oil phase, and the mass concentration of the monomers have an influence on the yield of the micro-crosslinked multi-branched cationic copolymer of the present invention; It can be seen from comparative example groups 1-5 that when the molar ratio of acrylamide to cationic monomer is (1-1.5):1 and the molar ratio of acrylamide to cationic monomer is 1.5:1, the yield of the prepared micro-crosslinked multi-branched cationic copolymer is the highest. This is because in the preparation process of the present invention, cationic monomers and acrylamide are mainly polymerized, so that the cationic monomers and acrylamide can be arranged in an orderly manner to form a long-chain polymer, and the molar ratio of acrylamide is crucial to the present invention. When the molar ratio of acrylamide to cationic monomer is (1-1.5):1, preferably acrylamide When the molar ratio of amine to cationic monomer is 1.5:1, the oil removal and water purification agent prepared therefrom has excellent effect. This is because if the molar ratio of acrylamide to cationic monomer is too large, acrylamide will undergo homopolymerization, thereby producing by-products, thereby affecting the yield of the micro-crosslinked multi-branched cationic copolymer, making the yield of the micro-crosslinked multi-branched cationic copolymer too low to affect the flocculation effect; and if the molar ratio of acrylamide to cationic monomer is too small, the cationic monomer and acrylamide will not be fully polymerized, thereby affecting the yield and molecular weight of the micro-crosslinked multi-branched cationic copolymer, and affecting the flocculation effect of the oil removal and water purification agent. By comparing Groups 6-15 and Groups 19-22, it can be seen that in the present invention, the amount of branching monomers, cross-linking monomers and initiators and the monomer mass concentration are very important for the present invention. This is because these materials are used as substrates for micro-cross-linked multi-branched cationic copolymers, and their most basic concentrations will affect the progress of the reaction to a certain extent. Increasing the concentration within a certain range is beneficial to the synthesis of micro-cross-linked multi-branched cationic copolymers, but as the substrate concentration increases, its ability to promote the reaction gradually tends to stabilize, and in the future, as the substrate concentration increases, it will trigger a series of side reactions, thereby affecting the yield of the micro-cross-linked multi-branched cationic copolymer. Only when the amount of branching monomers, cross-linking monomers and initiators is in a suitable range, the micro-cross-linked multi-branched cationic copolymer prepared therefrom has a high yield and weak side reactions, and does not produce many by-products.

[0050] By comparing groups 16-18, it can be seen that in the preparation method of the oil-removing and water-purifying agent in the present invention, the reverse emulsion polymerization method is mainly adopted, so that the water-soluble dispersed monomer is dispersed in the continuous oil phase with the help of the emulsifier to form a certain oil-in-water emulsion for polymerization reaction. Therefore, the volume ratio of the oil phase and the water phase is very important for the present invention. When the volume ratio of the oil phase and the water phase is 1:3, the oil-removing and water-purifying agent prepared therefrom has excellent effect; if there is too much oil phase, since the oil is used as the continuous phase to disperse the droplets, the nucleation mechanism is homogeneous nucleation and micelle nucleation, and too much oil phase will make the water-soluble dispersed monomer unable to be evenly dispersed in the oil phase, thereby affecting the polymerization reaction.

[0051] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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 highly efficient oil removal water purifier, characterized in that: Mainly comprising micro-crosslinked multi-branched cationic copolymer, fatty acid methyl ester ethoxylate, dodecyl dimethyl benzyl ammonium chloride and deionized water; The micro-crosslinked multi-branched cationic copolymer is mainly prepared from a non-polar solvent, a branching monomer, a crosslinking monomer, acrylamide, a cationic monomer, an emulsifier, an initiator, an organic solvent and deionized water, wherein the molar ratio of acrylamide to the cationic monomer is (1-1.5):1; The fatty acid methyl ester ethoxylate is mainly prepared from methyl stearate, a catalyst, ethylene oxide, isopropanol and deionized water, wherein the mass ratio of the catalyst to the methyl stearate is (0.005-0.015):1, and the mass ratio of the ethylene oxide to the methyl stearate is (0.5-1):

1.

2. The high-efficiency oil removal and water purification agent according to claim 1, characterized in that: The molar ratio of acrylamide to cationic monomer is 1.5:

1.

3. The high-efficiency oil removal and water purification agent according to claim 1, characterized in that: The mass ratio of the catalyst to the methyl stearate is 0.0125:1; The mass ratio of the ethylene oxide to the methyl stearate is 0.65:

1.

4. The high-efficiency oil removal and water purification agent according to claim 1, characterized in that: The non-polar solvent is one or more of methyl silicone oil, liquid paraffin and kerosene; The organic solvent is any one of anhydrous ethanol and acetone.

5. The high-efficiency oil removal and water purification agent according to claim 1, characterized in that: The branching monomer is trimethylolpropane triacrylate; The cross-linking monomer is 3-carboxypropyltrimethoxysilane; The cationic monomer is acryloyloxyethyl dimethylbenzyl ammonium chloride; The emulsifier is OP-10; The initiator is potassium sulfate-urea solution or azobisisobutyronitrile.

6. The high-efficiency oil removal and water purification agent according to claim 1, characterized in that: The catalyst is magnesium oxide-aluminum oxide.

7. A method for preparing a high-efficiency oil-removing water purifier according to any one of claims 1 to 6, characterized in that: The following steps are involved: preparing micro-crosslinked multi-branched cationic copolymers and fatty acid methyl ester ethoxylates respectively; Take deionized water, add fatty acid methyl ester ethoxylate and slightly cross-linked multi-branched cationic copolymer in sequence, and stir for 60-90 minutes to obtain a mixture; Take deionized water, add dodecyl dimethyl benzyl ammonium chloride to it, stir for 10-15 minutes, then slowly pour into the mixture, stir for 20-30 minutes, and obtain; The step of preparing the slightly cross-linked multi-branched cationic copolymer comprises adding a non-polar solvent, stirring, sequentially adding a branching monomer and a cross-linking monomer, and stirring sufficiently to obtain an oil phase for use; Take deionized water, add acrylamide, cationic monomer and emulsifier into it in sequence while stirring, and stir evenly to obtain a water phase; Slowly add the water phase to the oil phase under rapid stirring to obtain an inverse emulsion; Then, the initiator is added under nitrogen atmosphere at controlled temperature, cooled and stirred, an organic solvent is added, filtered, washed and dried to obtain the product; The steps of preparing fatty acid methyl ester ethoxylate are to add methyl stearate and a catalyst in sequence, then add ethylene oxide under a nitrogen atmosphere, add deionized water and isopropanol after cooling, and stir evenly to obtain the fatty acid methyl ester ethoxylate.

8. The preparation method according to claim 7, characterized in that: The amount of the branching monomer is 0.5-2% of the total amount of the branching monomer, the cross-linking monomer and the cationic monomer; The amount of the cross-linking monomer is 0.05-1% of the total amount of the branching monomer, the cross-linking monomer and the cationic monomer; The amount of the initiator used is 0.05-0.5% of the total amount of the branching monomer, the crosslinking monomer and the cationic monomer.

9. The preparation method according to claim 7, characterized in that: The volume ratio of the oil phase to the water phase is 1:

3.

10. The preparation method according to claim 7, characterized in that: The temperature control conditions are as follows: temperature of 30-50° C., dropwise addition time of 1-2 h, and rotation speed of 50-70 rpm.

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