High-efficiency oil-removing water purifying agent and preparation method thereof

Abstract

The application provides a high-efficiency oil-removing water purifying agent and a preparation method thereof. The oil-removing water purifying agent mainly comprises micro-crosslinking multi-branched cationic copolymer, fatty acid methyl ester ethoxylate, dodecyl dimethyl benzyl ammonium chloride and deionized water; the micro-crosslinking multi-branched cationic copolymer is prepared from non-polar solvent, branched monomer, crosslinking monomer, acrylamide, cationic monomer, emulsifier, initiator, organic solvent and deionized water; and the fatty acid methyl ester ethoxylate is prepared from methyl stearate, catalyst, ethylene oxide, isopropyl alcohol and deionized water. The high-efficiency oil-removing water purifying agent is mainly aimed at the defects of the existing oil-removing water purifying agent, uses the micro-crosslinking multi-branched cationic copolymer as a flocculant, uses the fatty acid methyl ester ethoxylate as a non-ionic surfactant, and through the synergistic effect of the two, so that the prepared oil-removing water purifying agent has better oil-removing effect and dispersion performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oily sewage treatment, and particularly relates to a high-efficiency oil removal water purifying agent and a preparation method thereof. BACKGROUND

[0002] In recent years, with the further development of industrialization, a large amount of oily sewage is generated in various industries such as oil refining, steel, food, textile and leather. The pollution parameters vary due to the industry and production, forming sewage with different characteristics. According to statistics, only the oil refineries in China produce up to 5.5 billion tons of oily sewage every year, and less than 50% of it meets the standard. Oily sewage 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 oilfields makes the oilfield oily wastewater complex, stable, high in oil content, poor in biodegradability and highly fluctuating, bringing great challenges to the treatment of oily wastewater. The current methods for treating oily sewage include solvent extraction, electrocoagulation, membrane separation, biotechnology, flotation, adsorption, cyclone separation and flocculation. Among them, the solvent extraction method requires high energy input in the solvent recovery and distillation process, and the solvent volatilization is large; the electrocoagulation method requires high electrical energy and has high electrode loss, and produces pollutants such as chlorinated organic matter and sludge; the biotechnology has low efficiency in treating oily sewage; the membrane separation is limited by membrane pollution, which limits its separation efficiency; the limitations of flotation technology include low efficiency, high energy demand, small oil selectivity and long time required to achieve the expected separation efficiency; in the adsorption method, the separation efficiency of fine oil particles is low, the cost of oil adsorbent is high, and the efficiency is low at high oil concentration; the cyclone separation method requires high energy, has low separation efficiency of oil particles and high maintenance cost; and the flocculation has the characteristics of simple operation, environmental friendliness, low cost and stable effect, and has been widely used in the treatment of oily sewage.

[0003] At present, the most commonly used oil removal water purifying agent for treating oily sewage in oilfields is cationic polyacrylamide flocculant. This kind of flocculant has the problems of low polymer molecular weight, weak adsorption bridging effect, poor water solubility, random distribution of cations on the molecular chain, uneven distribution of charge density, low utilization rate of cationic charge and weak interaction between the flocculant and sewage particles when treating oily sewage.

[0004] Therefore, the present application is proposed. SUMMARY

[0005] The first object of the present application is to provide a high-efficiency oil-removing water purifying agent, which is prepared by using a micro-crosslinking multi-branched cationic copolymer as a flocculant and a fatty acid methyl ester ethoxylate as a non-ionic surfactant, so that the prepared oil-removing water purifying agent has the characteristics of fast oil-water separation, short flocculation time and better oil-removing water purifying effect.

[0006] The second object of the present application is to provide a preparation method of a high-efficiency oil-removing water purifying agent, which is simple to operate, mild in operation condition, easy to control in reaction condition and stable in synthesis process.

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

[0008] The present application provides a high-efficiency oil-removing water purifying agent, which mainly comprises a micro-crosslinking multi-branched cationic copolymer, a fatty acid methyl ester ethoxylate, dodecyl dimethyl benzyl ammonium chloride and deionized water.

[0009] The micro-crosslinking 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, wherein the molar ratio of acrylamide to cationic monomer is (1-1.5):1.

[0010] The fatty acid methyl ester ethoxylate is mainly prepared from methyl stearate, a catalyst, ethylene oxide, isopropyl alcohol 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.

[0011] In the high-efficiency oil-removing water clarifier of the present application, long-chain polymers are generated through the mutual combination of branched monomers, crosslinking monomers, cationic monomers and acrylamide under specific conditions, atoms or chemical bonds are shared between various substances to orderly connect monomer molecules together, and then a micro-crosslinking multi-branched cationic copolymer with high molecular weight and continuous structure is formed. The micro-crosslinking multi-branched cationic copolymer is used as a flocculant in the oil-removing water clarifier, which has better flocculation effect and faster separation speed. The selection of branched monomers, crosslinking monomers and cationic monomers is very important to the present application, because only the selection of appropriate monomers can make the copolymer have a suitable physical structure, so that the performance of the polymer is excellent. When the branched monomer is trimethylolpropane triacrylate, the crosslinking monomer is 3-carboxyl propyl trimethoxysilane, and the cationic monomer is acryloyloxyethyl dimethyl benzyl ammonium chloride, the micro-crosslinking multi-branched cationic copolymer prepared has excellent effect, because trimethylolpropane triacrylate, as a commonly used hydrophobic branched monomer, has the characteristics of strong hydrophobicity, and as a hydrophobic monomer, it can enhance the hydrophobic association when introduced into the reaction system to form a copolymer, so that the prepared flocculant can better accelerate the separation speed between oil flocs and water, and the flocculation effect of the oil-removing water clarifier is better. Since trimethylolpropane triacrylate monomer has more chemical bonds, the three double bonds contained therein can better polymerize with other monomer substances, and the 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 phenomenon between ordinary molecular chains is reduced, the overall conformation is more stretched, and the hydrodynamic volume is larger. This structure can greatly improve the utilization rate of cationic charge, enhance the electric neutralization capacity, and also enhance the adsorption bridging effect, so that more cationic adsorption sites are provided on the molecular chain produced by the copolymerization reaction, effectively neutralizing the surface charge of particles, thereby promoting the flocculation process and accelerating the flocculation rate of the oil-removing water clarifier. Moreover, since trimethylolpropane triacrylate monomer has more chemical bonds, it can better copolymerize with other monomer substances, so that more monomer substances can be connected to trimethylolpropane triacrylate monomer, thereby enabling more monomer molecules to be orderly connected to form a copolymer with higher molecular weight, greatly improving the flocculation effect of the oil-removing water clarifier.

[0012] Therefore, from the above description, it can be known that the molar ratio between the acrylamide and the cationic monomer is very important, because in the preparation process of the present application, the cationic monomer and the acrylamide are mainly polymerized to arrange the cationic monomer and the acrylamide in order to form a long-chain polymer, and the molar ratio of the acrylamide is crucial to the present application. When the molar ratio of the acrylamide to the cationic monomer is (1-1.5):1, preferably the molar ratio of the acrylamide to the cationic monomer is 1.5:1, the prepared oil removal and water purification agent has excellent effect, because if the molar ratio of the acrylamide to the cationic monomer is too large, the acrylamide will homopolymerize to produce by-products, thereby affecting the yield of the micro-crosslinking and multi-branched cationic copolymer, and the flocculation effect is affected by the low yield of the micro-crosslinking and multi-branched cationic copolymer; and if the molar ratio of the acrylamide to the cationic monomer is too small, the cationic monomer and the acrylamide cannot be fully polymerized, thereby affecting the yield and molecular weight of the micro-crosslinking and multi-branched cationic copolymer, and the flocculation effect of the oil removal and water purification agent is affected.

[0013] Preferably, as a further specific embodiment, the molar ratio of the acrylamide to the cationic monomer is 1.5:1.

[0014] Preferably, as a further specific embodiment, the mass ratio of the catalyst to the methyl stearate is 0.0125:1.

[0015] The mass ratio of the ethylene oxide to the methyl stearate is 0.65:1.

[0016] In the present application, the fatty acid methyl ester ethoxylate is used as a non-ionic surfactant, so that the prepared oil removal water purifier has low foam, high cloud point, is not easy to gel in cold water, has fast dissolution speed and better oil removal and dispersion effect. The mass ratio of ethylene oxide and methyl stearate in the fatty acid methyl ester ethoxylate is very important, because the application environment of the oil removal water purifier provided by the present application is harsh, and the temperature is low. The oil removal water purifier prepared by using traditional surfactants has poor flowability at low temperature, low cloud point, and is easy to coagulate in cold water, so that the oil removal and dispersion effect of the oil removal water purifier is poor. As a non-ionic surfactant, the fatty acid methyl ester ethoxylate is obtained by direct addition reaction of methyl stearate and ethylene oxide under the action of a catalyst. Compared with traditional fatty alcohol ethoxylates, the fatty acid methyl ester ethoxylate exhibits significant differences. First, it has low foam generation capacity, which means that the surface can be better maintained during use. In addition, the fatty acid methyl ester ethoxylate has a high cloud point, which means that it can maintain good flowability in low-temperature environments, and can easily cope with various application conditions even in winter. The fatty acid methyl ester ethoxylate has extremely fast dissolution speed in cold water, thereby greatly improving its use convenience, so that the prepared oil removal water purifier can be quickly and uniformly dispersed in water without additional heating steps, and has excellent performance for removing oil and dirt. In the oil removal water purifier of the present application, only when the mass ratio of ethylene oxide and methyl stearate is in a suitable range, the fatty acid methyl ester ethoxylate prepared has high yield, can well synergize with the micro-crosslinking multi-branched cationic copolymer, and achieve better oil removal and flocculation effect. In the preparation process of the 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. 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 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 prepared fatty acid methyl ester ethoxylate has high yield, can well synergize with the micro-crosslinking multi-branched cationic copolymer, and achieve better oil removal and flocculation effect.

[0017] Preferably, as a further specific embodiment, the non-polar solvent is one or more of methyl silicone oil, liquid paraffin and kerosene.

[0018] The organic solvent is any one of anhydrous ethanol and acetone.

[0019] And in the present application also by using non-polar solvent to prepare more micro-crosslinking multi-branched cationic copolymer, wherein the non-polar solvent is one or more of methyl silicone oil, liquid paraffin and kerosene, preferably the non-polar solvent is methyl silicone oil, the prepared oil removal water purifier effect is excellent, because in the present application is mainly by using non-polar solvent to increase the solubility of branched monomer and crosslinking monomer, so that branched monomer and crosslinking monomer can be more dissolved in solution, in turn to prepare more micro-crosslinking multi-branched cationic copolymer, better improve the sewage treatment effect of oil removal water purifier, wherein when using methyl silicone oil as non-polar solvent to dissolve branched monomer and crosslinking monomer, the solubility of branched monomer and crosslinking monomer is higher.

[0020] Preferably, as a further specific embodiment, the branched monomer is trimethylolpropane triacrylate;

[0021] The crosslinking monomer is 3-carboxyl propyl trimethoxysilane;

[0022] The cationic monomer is acryloyloxyethyl dimethyl benzyl ammonium chloride;

[0023] The emulsifier is OP-10;

[0024] The initiator is potassium sulfate-urea solution or azobisisobutyronitrile.

[0025] Preferably, as a further specific embodiment, the catalyst is magnesium oxide-aluminum oxide.

[0026] The present application also provides a preparation method of the above-mentioned high-efficiency oil removal water purifier, comprising the following steps:

[0027] Preparation of micro-crosslinking multi-branched cationic copolymer and fatty acid methyl ester ethoxylate, respectively;

[0028] Take deionized water, add fatty acid methyl ester ethoxylate and micro-crosslinking multi-branched cationic copolymer to it in turn, stir for 60-90 min, and get the mixture;

[0029] Take deionized water, add dodecyl dimethyl benzyl ammonium chloride to it, stir for 10-15 min, then slowly pour into the mixture, stir for 20-30 min, and get the product;

[0030] The step of preparing micro-crosslinking multi-branched cationic copolymer is to add non-polar solvent, then add branched monomer and crosslinking monomer in turn after stirring, and get the oil phase for standby after sufficient stirring;

[0031] Take deionized water, add acrylamide, cationic monomer and emulsifier to it in turn while stirring, and get the water phase after stirring uniformly;

[0032] The water phase is slowly added dropwise into the oil phase under rapid stirring to obtain a reverse phase emulsion;

[0033] Subsequently, the initiator is added under temperature control in a nitrogen atmosphere, and after cooling, the organic solvent is added, and the product is obtained by filtration, washing and drying.

[0034] The preparation of fatty acid methyl ester ethoxylate is carried out by sequentially adding methyl stearate and a catalyst, then adding ethylene oxide under a nitrogen atmosphere, and then adding deionized water and isopropyl alcohol after cooling, and stirring uniformly.

[0035] In the preparation method of the micro-crosslinking multi-branched cationic copolymer, the temperature is controlled when the initiator is added. If the temperature is too high and the speed is too fast when the initiator is added, the micro-crosslinking multi-branched cationic copolymer will undergo side reactions during preparation, thereby affecting the yield of the micro-crosslinking multi-branched cationic copolymer. When the temperature is set to 30-50℃, the dropping time is 1-2h, and the speed is 50-70rpm, the yield of the micro-crosslinking multi-branched cationic copolymer prepared is high. After the addition of the initiator is completed, the temperature needs to be raised again to facilitate the continuation of the reaction. The temperature needs to be raised to 60-80℃ after the addition is completed, and the reaction is carried out again for 4-5h, so that the yield of the micro-crosslinking multi-branched cationic copolymer prepared is higher, and side reactions are avoided.

[0036] In the preparation method of the micro-crosslinking multi-branched cationic copolymer, the temperature is controlled when the initiator is added. If the temperature is too high and the speed is too fast when the initiator is added, the micro-crosslinking multi-branched cationic copolymer will undergo side reactions during preparation, thereby affecting the yield of the micro-crosslinking multi-branched cationic copolymer. When the temperature is set to 30-50℃, the dropping time is 1-2h, and the speed is 50-70rpm, the yield of the micro-crosslinking multi-branched cationic copolymer prepared is high. After the addition of the initiator is completed, the temperature needs to be raised again to facilitate the continuation of the reaction. The temperature needs to be raised to 60-80℃ after the addition is completed, and the reaction is carried out again for 4-5h, so that the yield of the micro-crosslinking multi-branched cationic copolymer prepared is higher, and side reactions are avoided.

[0037] In the preparation process of the fatty acid methyl ester ethoxylate, the feeding conditions are adjusted to temperature: 120℃, speed: 50rpm when ethylene oxide is introduced, and the temperature is raised to 150℃, speed: 50rpm, pressure: 0.3-0.4MPa after the introduction is completed, and the reaction is carried out for 4.5h, so that the reaction is more complete; and in the subsequent mixing of the water phase and the oil phase, an emulsifier is added to promote the contact and exchange between the two phases.

[0038] Preferably, as a further specific embodiment, the amount of the branched monomer is 0.5-2% of the total amount of the branched monomer, the crosslinking monomer and the cationic monomer;

[0039] 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;

[0040] The amount of the initiator is 0.05-0.5% of the total amount of the branching monomer, the cross-linking monomer and the cationic monomer.

[0041] In the present application, the amount of the branching monomer, the cross-linking monomer and the initiator is very important for the present application, because these substances are the substrates of the micro-cross-linking multi-branching cationic copolymer, and the basic concentration of these substances will affect the reaction process to some extent, and the increase of the concentration within a certain range is conducive to the synthesis of the micro-cross-linking multi-branching cationic copolymer, but as the concentration of the substrates increases, the ability to promote the reaction gradually tends to be stable, and further increase of the concentration of the substrates will trigger a series of side reactions, thereby affecting the yield of the micro-cross-linking multi-branching cationic copolymer. Only when the amount of the branching monomer, the cross-linking monomer and the initiator is within a suitable range, the micro-cross-linking multi-branching cationic copolymer prepared has high yield and weak by-products, and the by-products are less.

[0042] Preferably, as a further specific embodiment, the volume ratio of the oil phase to the water phase is 1:3.

[0043] In the preparation method of the oil removal water purifier in the present application, the water-soluble dispersed monomer is dispersed in the continuous oil phase by the action of the emulsifier to form a certain water-in-oil emulsion for polymerization by using the inverse emulsion polymerization method, so the volume ratio of the oil phase to the water phase is very important for the present application. When the volume ratio of the oil phase to the water phase is 1:3, the prepared oil removal water purifier has excellent effect. If the oil phase is too much, the nucleation mechanism is homogeneous nucleation and micellar nucleation because the oil is used as the continuous phase of the dispersed droplets, and the water-soluble dispersed monomer cannot be uniformly dispersed in the oil phase when the oil phase is too much, thereby affecting the polymerization reaction.

[0044] Preferably, as a further specific embodiment, the temperature control condition is that the temperature is 30-50℃, the dropping time is 1-2h, and the rotation speed is 50-70rpm.

[0045] In the present application, the temperature control condition when the initiator is added is very important. When the temperature control condition is that the temperature is 30-50℃, the dropping time is 1-2h, and the rotation speed is 50-70rpm, the polymerization reaction between the monomers can occur better under the initiation of the initiator, thereby making the yield of the micro-cross-linking multi-branching cationic copolymer higher. When the water phase and the oil phase are mixed, the water-soluble monomer is dispersed in the oil phase under the action of the emulsifier to form a water-in-oil emulsion for polymerization, which is an exothermic reaction. Therefore, if the initiator is added too fast, the exothermic reaction may be too intense, which affects the polymerization effect.

[0046] Compared with the prior art, the present application has the advantages of:

[0047] (1) The high-efficiency oil-removing water clarifier provided by the present application has the characteristics of fast oil-water separation, short flocculation time and better oil-removing water clarification effect, because the micro-crosslinking multi-branched cationic copolymer is used as the flocculant and the fatty acid methyl ester ethoxylate is used as the non-ionic surfactant.

[0048] (2) The preparation method of the high-efficiency oil-removing water clarifier provided by the present application is simple to operate, has mild operating conditions, easy-to-control reaction conditions and stable synthesis process. DETAILED DESCRIPTION

[0049] The technical solutions of the present application will be described clearly and completely in combination with specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, not all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0050] In order to more clearly describe the technical solutions in the present application, the following will be described in the form of specific embodiments.

[0051] Embodiment 1

[0052] The specific preparation process of the high-efficiency oil-removing water clarifier of the present application is as follows:

[0053] (1) Preparation of micro-crosslinking multi-branched cationic copolymer

[0054] The amount of branched monomer is 0.5% of the total amount of branched monomer, crosslinking monomer and cationic monomer;

[0055] The amount of crosslinking monomer is 0.05% of the total amount of branched monomer, crosslinking monomer and cationic monomer;

[0056] The amount of initiator is 0.05% of the total amount of branched monomer, crosslinking monomer and cationic monomer;

[0057] First step: preparation of oil phase. Add methyl silicone oil into the reaction bottle, start mechanical stirring at 100 rpm, then add a certain amount of trimethylolpropane triacrylate and 3-carboxylpropyl trimethoxysilane in turn, and fully stir to dissolve to obtain the oil phase;

[0058] Second step: preparation of aqueous phase. Add a certain amount of deionized water to a beaker, start mechanical stirring at 100 rpm, then add acrylamide, acryloyloxyethyl dimethyl benzyl ammonium chloride and OP-10 in turn according to the molar ratio of acrylamide to acryloyloxyethyl dimethyl benzyl ammonium chloride is 1:1, 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 standby;

[0059] Third step: preparation of inverse emulsion. Under the condition of rapid stirring at 100 rpm, slowly add the aqueous phase to the oil phase, stir for a certain time, at this time the volume ratio of oil phase to aqueous phase is 1:3, and a stable inverse emulsion is prepared;

[0060] Fourth step: synthesis of copolymer. Equip the reaction bottle with a thermometer, a condenser (water-cooled), and a glass air guide tube, pass nitrogen for 1 h, evacuate the reaction bottle, and continuously pass nitrogen to protect the subsequent reaction. Control the temperature at 30℃, and slowly add the potassium sulfate-urea solution for 1 h under the condition of 50 rpm. After the addition is completed, increase the temperature to 60℃, and continue to react for 4 h under the condition of 50 rpm. After the reaction is completed, cool to room temperature, and add anhydrous ethanol under stirring conditions. Then, filter, wash with anhydrous ethanol, and dry to obtain a micro-crosslinked multi-branched cationic copolymer.

[0061] (2) Preparation of fatty acid methyl ester ethoxylate

[0062] Take methyl stearate as the starting agent, add magnesium oxide-aluminum oxide according to the mass ratio of magnesium oxide-aluminum oxide to methyl stearate of 0.005:1, pass nitrogen to evacuate the air in the reaction kettle, then introduce ethylene oxide into the reaction kettle according to the mass ratio of ethylene oxide to methyl stearate of 0.5:1 under the conditions of temperature 120℃ and stirring speed 50 rpm, pass nitrogen again to evacuate the air in the reaction kettle, seal the system under the reaction conditions of temperature 150℃, stirring speed 50 rpm, and reaction pressure 0.3 MPa, and perform ethoxylation reaction for 4.5 h.

[0063] After the reaction is completed, age and cool to 120℃, then pass cooling water to cool to 60℃, add deionized water and isopropanol, stir uniformly, and discharge the product under nitrogen.

[0064] (3) Preparation of high-efficiency oil-removing water clarifier

[0065] Take deionized water, and add fatty acid methyl ester ethoxylate and micro-crosslinked multi-branched cationic copolymer into the deionized water in turn, stir for 60 min to obtain a mixture;

[0066] Take deionized water, add dodecyl dimethyl benzyl ammonium chloride into the deionized water, stir and dissolve for 10 min to obtain a dodecyl dimethyl benzyl ammonium chloride solution;

[0067] The solution of dodecyl dimethyl benzyl ammonium chloride is added into the mixture, and the stirring is continued for 20 min to obtain the product.

[0068] Example 2

[0069] The specific preparation process of the high-efficiency oil-removing water clarifier is as follows:

[0070] (1) Preparation of micro-cross-linked multi-branched cationic copolymer

[0071] The amount of branched monomer is 2% of the total amount of branched monomer, cross-linking monomer and cationic monomer;

[0072] The amount of cross-linking monomer is 1% of the total amount of branched monomer, cross-linking monomer and cationic monomer;

[0073] The amount of initiator is 0.5% of the total amount of branched monomer, cross-linking monomer and cationic monomer;

[0074] First step: preparation of oil phase. Add kerosene into the reaction bottle, start mechanical stirring at 100 rpm, then add a certain amount of trimethylolpropane triacrylate and 3-carboxyl propyl trimethoxysilane in sequence, and fully stir to dissolve to obtain the oil phase;

[0075] Second step: preparation of water phase. Add a certain amount of deionized water into the beaker, start mechanical stirring at 100 rpm, then add acrylamide, acryloyloxyethyl dimethyl benzyl ammonium chloride and OP-10 in sequence according to the molar ratio of acrylamide to acryloyloxyethyl dimethyl benzyl ammonium chloride being 1.5:1, prepare a monomer solution with a mass concentration of 50%, and stir until completely dissolved to obtain the water phase, which is transferred to a constant-pressure dropping funnel for standby;

[0076] Third step: preparation of reverse emulsion. Under the condition of rapid stirring at a speed of 150 rpm, the water phase is slowly added into the oil phase, and stirring is continued for 35 min, at which time the volume ratio of oil phase to water phase is 1:3, to obtain a stable reverse emulsion;

[0077] Fourth step: synthesis of copolymer. Equip the reaction bottle with a thermometer, a condenser (water-cooled) and a glass air guide tube, and pass nitrogen for 1 h, empty the air in the reaction bottle, and continuously pass nitrogen to protect the subsequent reaction. The temperature is controlled at 50℃, and the stirring speed is 70 rpm. 2,2'-azobis(2-methylpropionitrile) is slowly added for 2 h. After the addition is completed, the temperature is increased to 80℃, and the stirring speed is 70 rpm. The reaction is continued for 5 h. After the reaction is completed, the temperature is cooled to room temperature. Under the stirring condition, acetone is added, and the mixture is filtered, washed with acetone and dried to obtain the micro-cross-linked multi-branched cationic copolymer.

[0078] (2) Preparation of fatty acid methyl ester ethoxylate

[0079] The mass ratio of magnesium oxide-aluminum oxide and methyl stearate is 0.015:1, and the catalyst is added according to the feeding ratio, nitrogen is introduced into the reaction kettle to exhaust air, then under the conditions of temperature 120 DEG C and rotation speed 50 rpm, the reaction kettle is introduced into ethylene oxide according to the mass ratio of ethylene oxide and methyl stearate 1:1, nitrogen is introduced into the reaction kettle again to exhaust air, and the system is sealed under the reaction conditions of temperature 150 DEG C, rotation speed 50 rpm and reaction pressure 0.4 MPa, and the ethoxylation reaction is carried out for 4.5 h;

[0080] After the reaction is completed, aging and cooling to 120 DEG C are carried out, then cooling water is introduced to cool to 60 DEG C, deionized water and isopropyl alcohol are added, stirring is uniformly carried out, nitrogen is introduced to guide out the product.

[0081] (3) Preparation of high-efficiency oil-removing water clarifier

[0082] Deionized water is taken, and fatty acid methyl ester ethoxylate and micro-crosslinking multi-branched cationic copolymer are sequentially added into the deionized water, and stirring is carried out for 90 min to obtain a mixture;

[0083] Deionized water is taken, and dodecyl dimethyl benzyl ammonium chloride is added into the deionized water, stirring is carried out for 15 min, and then a dodecyl dimethyl benzyl ammonium chloride solution is obtained;

[0084] The dodecyl dimethyl benzyl ammonium chloride solution is added into the mixture, and stirring is continuously carried out for 30 min, and then the product is obtained.

[0085] Example 3

[0086] The specific preparation process of the high-efficiency oil-removing water clarifier is as follows:

[0087] (1) Preparation of micro-crosslinking multi-branched cationic copolymer

[0088] The amount of the branched monomer is 1% of the total amount of the branched monomer, the crosslinking monomer and the cationic monomer;

[0089] The amount of the crosslinking monomer is 0.5% of the total amount of the branched monomer, the crosslinking monomer and the cationic monomer;

[0090] The amount of the initiator is 0.5% of the total amount of the branched monomer, the crosslinking monomer and the cationic monomer;

[0091] First step: preparation of the oil phase. Methyl silicone oil is added into a reaction bottle, mechanical stirring is started at 100 rpm, and then a certain amount of trimethylolpropane triacrylate and 3-carboxyl propyl trimethoxysilane are sequentially added, and stirring is carried out to dissolve them to obtain the oil phase;

[0092] Step 2: Prepare the aqueous phase. Add a certain amount of deionized water to a beaker and start mechanical stirring at 100 rpm. Then, add acrylamide, acryloxyethyl dimethyl benzyl ammonium chloride, and OP-10 in a molar ratio of 1.5:1 to prepare a 30% monomer solution. Stir until completely dissolved. Transfer the aqueous phase to a constant pressure dropping funnel for later use.

[0093] Step 3: Prepare an inverse emulsion. Slowly add the aqueous phase dropwise to the oil phase while stirring at 100 rpm and stir for a certain period of time. At this point, the volume ratio of the oil phase to the aqueous phase is 1:3, thus producing a stable inverse emulsion.

[0094] Step 4: Synthesis of the copolymer. Equip the reaction flask with a thermometer, a water-cooled condenser, and a glass gas guide tube. Flow nitrogen for 1 hour to evacuate the air from the flask. Continue flowing nitrogen to protect the subsequent reaction. Slowly add potassium sulfate-urea dropwise for 2 hours at a controlled temperature of 50°C and a rotation speed of 70 rpm. After the addition is complete, raise the temperature to 80°C and continue the reaction at a rotation speed of 70 rpm for 5 hours. After the reaction is complete, cool to room temperature, add an organic solvent with stirring, filter, wash with the organic solvent, and dry to obtain a slightly cross-linked, multi-branched cationic copolymer.

[0095] (2) Preparation of fatty acid methyl ester ethoxylates

[0096] Methyl stearate was used as an initiator, magnesium oxide-alumina was added according to a feeding 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 feeding conditions of a temperature of 120° C. and a rotation speed of 50 rpm. The air in the reactor was again evacuated by nitrogen, and the system was sealed and ethoxylated 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.

[0097] After the reaction, the mixture was aged and cooled to 120°C, and then cooled to 60°C by cooling water. Deionized water and isopropanol were added, stirred evenly, and nitrogen was injected to remove the product.

[0098] (3) Preparation of high-efficiency oil removal and water purification agent

[0099] 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;

[0100] Take deionized water, add dodecyldimethylbenzyl ammonium chloride to the deionized water, stir and dissolve for 15 minutes to obtain dodecyldimethylbenzyl ammonium chloride solution;

[0101] A solution of dodecyl dimethyl benzyl ammonium chloride was added to the mixture, and stirring was continued for 20 min to obtain the product.

[0102] The oil removal agent prepared in Example 1-3 and a commercially available oil removal agent were tested for sewage treatment effect, and the test results are shown in Table 1 below:

[0103] Table 1 Test results

[0104]

[0105] Therefore, from the above experimental data, it can be known that the oil removal agent prepared by the present application has excellent performance, and the oil removal rate is better than that of the commercially available product.

[0106] Experimental Example 1 Effect of material ratio on preparation of micro-crosslinking multi-branched cationic copolymer

[0107] The preparation steps of the micro-crosslinking multi-branched cationic copolymer are as follows:

[0108] First step: preparation of oil phase. A certain amount of methyl silicone oil was added to a reaction bottle, and mechanical stirring was started at 100 rpm. Then a certain amount of trimethylolpropane triacrylate and 3-carboxyl propyl trimethoxysilane were added in sequence, and the specific amounts of trimethylolpropane triacrylate and 3-carboxyl propyl trimethoxysilane are shown in Table 2.1. The oil phase was obtained by fully stirring to dissolve.

[0109] Second step, preparation of water phase. A certain amount of deionized water was added to a beaker, and mechanical stirring was started at 100 rpm. Then acrylamide (AM), acryloyloxyethyl dimethyl benzyl ammonium chloride (DBAC) and OP-10 were added in sequence to prepare a solution with the monomer mass concentration shown in Table 2.3. The specific amounts of acrylamide (AM), acryloyloxyethyl dimethyl benzyl ammonium chloride (DBAC) and OP-10 are shown in Table 2.1. The water phase was obtained by stirring to completely dissolve and was transferred to a constant pressure dropping funnel for standby.

[0110] Third step, preparation of inverse emulsion. Mechanical stirring was started at 150 rpm. The water phase was slowly added to the oil phase according to the volume ratio shown in Table 2.2, and stirring was continued for 30 min to obtain a stable inverse emulsion.

[0111] Fourth step, synthesis of copolymer. The reaction bottle is equipped with a thermometer, a condenser (water-cooled), a glass air duct, and nitrogen is passed for 1 h. The reaction bottle is evacuated of air and the subsequent reaction is protected by continuous nitrogen flow. The temperature is controlled at 30°C and 70 rpm. The potassium sulfate-urea solution is slowly added dropwise for 2 h. After the dropwise addition is completed, the temperature is increased to 80°C and the reaction is continued at 70 rpm for 5 h. After the reaction is completed, the temperature is cooled to room temperature. Under stirring conditions, acetone is added. Filtration, acetone washing, and drying are performed to obtain the micro-crosslinked multi-branched cationic copolymer. The yield is calculated and the final results are shown below.

[0112] Table 2.1 Experimental material ratio and results

[0113]

[0114] Table 2.2 Oil phase to water phase volume ratio and results

[0115]

[0116] Table 2.3 Effect of monomer mass concentration on results

[0117]

[0118] Experimental Example 2 Determination of the treatment effect of the oil removal and water purification agent on oil-containing wastewater

[0119] In this experimental example, the effect of the oil removal and water purification agent obtained in groups 8-15 in Experimental Example 3 on wastewater treatment is determined. The determination results are shown in Table 3.

[0120] Table 3

[0121]

[0122] From the above experimental data, it can be known that the molar ratio of acrylamide (AM) and acryloyloxyethyl dimethyl benzyl ammonium chloride, the amount of each monomer, the volume ratio between the water phase and the oil phase, and the monomer mass concentration have an effect on the yield of the micro-crosslinked multi-branched cationic copolymer of the present application.

[0123] It can be known from the comparative group 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 micro-crosslinking multi-branched cationic copolymer prepared has the highest yield, because in the preparation process of the present application, the cationic monomer and acrylamide are mainly polymerized to form long-chain polymers, and the molar ratio of acrylamide is crucial to the present application. When the molar ratio of acrylamide to cationic monomer is (1-1.5):1, preferably the molar ratio of acrylamide to cationic monomer is 1.5:1, the oil removal water clarifier prepared has excellent effect, because if the molar ratio of acrylamide to cationic monomer is too large, the acrylamide will homopolymerize to produce by-products, thereby affecting the yield of the micro-crosslinking multi-branched cationic copolymer, and the flocculation effect is affected. If the molar ratio of acrylamide to cationic monomer is too small, the cationic monomer and acrylamide cannot fully polymerize, thereby affecting the yield and molecular weight of the micro-crosslinking multi-branched cationic copolymer, and the flocculation effect of the oil removal water clarifier is affected.

[0124] It can be known from the comparative group 6-15 and group 19-22 that in the present application, the amount of branched monomer, crosslinking monomer and initiator and the mass concentration of monomer are very important, because these materials are the substrate of the micro-crosslinking multi-branched cationic copolymer, and the basic concentration will affect the reaction process to some extent. Within a certain range, the increase of concentration is conducive to the synthesis of the micro-crosslinking multi-branched cationic copolymer, but as the concentration of the substrate increases, the ability to promote the reaction gradually stabilizes, and with the increase of the substrate concentration, a series of side reactions will be triggered, thereby affecting the yield of the micro-crosslinking multi-branched cationic copolymer. Only when the amount of branched monomer, crosslinking monomer and initiator is in a suitable range, the micro-crosslinking multi-branched cationic copolymer prepared has high yield and weak side reactions, and many by-products are not produced.

[0125] It can be known from the comparative group 16-18 that in the preparation method of the oil removal water clarifier in the present application, the reverse emulsion polymerization method is mainly used to disperse the water-soluble dispersed monomer in the continuous oil phase by the action of the emulsifier to form a certain water-in-oil emulsion for polymerization reaction, so the volume ratio of oil phase and water phase is very important to the present application. When the volume ratio of oil phase and water phase is 1:3, the oil removal water clarifier prepared has excellent effect. If the oil phase is too much, because the oil is used as the continuous phase dispersion droplet, the nucleation mechanism is homogeneous nucleation and micellar nucleation, and too much oil phase will cause the water-soluble dispersed monomer to be unable to disperse uniformly in the oil phase, thereby affecting the polymerization reaction.

[0126] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-efficiency oil removal and water purification agent, characterized in that: The invention comprises a micro-crosslinked multi-branched cationic copolymer, fatty acid methyl ester ethoxylate, dodecyldimethylbenzyl ammonium chloride and deionized water; The slightly cross-linked multi-branched cationic copolymer is prepared from a non-polar solvent, a branching monomer, a cross-linking monomer, acrylamide, a cationic monomer, an emulsifier, an initiator, an organic solvent and deionized water, wherein the molar ratio of the acrylamide to the cationic monomer is (1-1.5):1; The branching monomer is trimethylolpropane triacrylate; The cross-linking monomer is 3-carboxypropyltrimethoxysilane; The cationic monomer is acryloyloxyethyl dimethylbenzyl ammonium chloride; The fatty acid methyl ester ethoxylate is prepared from methyl stearate, a catalyst, ethylene oxide, isopropyl alcohol 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 the acrylamide to the 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 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: Micro-crosslinked multi-branched cationic copolymers and fatty acid methyl ester ethoxylates were prepared respectively; 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 60-90 minutes to obtain a mixture; Take deionized water, add dodecyl dimethyl benzyl ammonium chloride to it, stir for 10-15 minutes, then slowly pour it into the mixture and stir for 20-30 minutes to obtain; The step of preparing the slightly cross-linked multi-branched cationic copolymer comprises adding a non-polar solvent, stirring, and then sequentially adding a branching monomer and a cross-linking monomer, and stirring thoroughly 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 an aqueous phase; Slowly add the water phase dropwise 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 as follows: adding methyl stearate and a catalyst in sequence, then adding ethylene oxide under a nitrogen atmosphere, cooling, adding deionized water and isopropyl alcohol, and stirring 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 30-50° C., dropwise addition time 1-2 h, and rotation speed 50-70 rpm.

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