An amphiphilic magnetically responsive organic affinity adsorbent and its preparation method and application

Abstract

An amphiphilic magnetically responsive organic affinity adsorbent and its preparation method and application, wherein one or two of urea and thiourea are mixed and heated with quaternary ammonium salt choline to obtain a eutectic solvent; after the eutectic solvent is mixed with an organic solvent, a surfactant is added to obtain an organic electrolyte, and an iron sheet is used as an anode and a cathode. By applying a continuous current, the anode iron atom is stripped and oxidized to an amino magnetic nano-iron oxide, and the surfactant derives an organic ligand that is connected to the amino magnetic nano-iron oxide through an amino group to generate a liganded nano-magnetic particle unit in situ; after the electrolysis is completed, the separated liganded nano-magnetic particle unit is transferred to water for self-assembly to obtain an amphiphilic magnetically responsive organic affinity adsorbent. The method adjusts the affinity speed and the adsorption amount of the adsorbent by adjusting the composition and content of the ligand carried by the prepared adsorbent, thereby expanding the application field of the adsorbent; the obtained adsorbent can efficiently adsorb and treat organic pollutants in the liquid phase.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of organic affinity adsorbents, and specifically relates to an amphiphilic magnetic-responsive organic affinity adsorbent and a preparation method and application thereof. Background Art

[0002] Organic pollution in water bodies causes a certain degree of harm to the survival of aquatic organisms and the health of humans and animals. The intake of persistent organic pollutants can cause endocrine system disorders, reproductive and immune system damage, cancer, deformities, gene mutations and neurological diseases in animals, including humans. The bioaccumulation effect in the water environment can make the harm last for decades (Science, 2016, 352, 1388; Nat. Food, 2020, 1, 292). The effective removal of organic pollutants in water bodies is an inevitable requirement for improving the quality of the water environment and a continuous challenge faced by water purification and management. The removal of trace organic pollutants in liquid environments often adopts enrichment and separation methods. This method adopts affinity adsorption technology, which has the characteristics of wide materials, simple procedures, mild conditions, etc. It is a technical route with high comprehensive cost performance (Adv. Mater., 2020, 32, 1907932; Adv. Funct. Mater., 2021, 31, 2007356). Traditional adsorption materials (based on biomass, activated carbon, natural clay, silica gel and other substrates) have the characteristics of stable physical and chemical properties and low cost, but they usually face problems such as weak affinity efficiency, low adsorption saturation and difficult process control during use. This makes them often only suitable for extensive adsorption scenarios and difficult to meet the development needs of increasingly refined and trace organic polluted water treatment (Sep. Purif. Technol., 2019, 228, 115719; Adv. Colloid Interface, 2021, 297, 102537).

[0003] In recent years, new adsorbents with hydrophilicity, hydrophobicity, amphiphilicity and magnetic responsiveness have been synthesized and used to remove organic pollutants in liquid environments. Magnetic responsive adsorbents have the characteristics of strong affinity, high adsorption capacity, wide application scenarios and convenient operation. They also have recovery efficiency that is difficult to match with other adsorbents. They have broad application prospects in the field of liquid environment organic pollutant treatment. Organic pollutants are divided into water-soluble and water-insoluble types. Compared with magnetic responsive adsorbents loaded with simple lipophilic or hydrophilic ligands, amphiphilic magnetic responsive adsorbents have great application potential in the purification of organic polluted water bodies, and they have wider application scenarios.

[0004] The composition and content of the ligands determine, to a certain extent, the speed of the adsorbent affinity rate and the amount of adsorption. The key to the controllable construction of amphiphilic magnetic-responsive adsorbents lies in the adjustable and controllable composition and content of the amphiphilic affinity ligands. Chemical precipitation, hydrothermal, pyrolysis, microemulsion, sol-gel, etc. are all difficult to achieve adjustable and controllable ligands while completing the synthesis of magnetic-responsive complexes. The unique physical and chemical properties of amphiphilic magnetic-responsive adsorbents and their objective usage requirements pose many challenges to the conventional construction principles, synthetic routes, and preparation strategies of magnetic-responsive adsorbents. Their adjustable and controllable construction is a major technical problem in the field of magnetic-responsive adsorbent preparation. Summary of the invention

[0005] The purpose of the present invention is to provide an amphiphilic magnetic responsive adsorbent and a preparation method and application thereof. The method can regulate the affinity speed and adsorption amount of the adsorbent by regulating the composition and content of the ligand carried by the prepared adsorbent, thereby expanding the application field and applicable scenarios of the adsorbent; the prepared adsorbent can efficiently adsorb and treat typical organic pollutants such as antibiotics, organic pesticides and aliphatic hydrocarbons in the liquid phase.

[0006] In order to achieve the above object, the present invention provides a method for preparing an amphiphilic magnetically responsive organic affinity adsorbent, comprising the following steps:

[0007] (1) mixing one or both of urea and thiourea with quaternary ammonium salt choline in a certain proportion, and heating in a sealed manner to obtain a eutectic solvent;

[0008] (2) mixing the eutectic solvent obtained in step (1) with a polar organic solvent in a certain volume ratio, and then adding a surfactant to obtain a eutectic solvent mixed solution;

[0009] (3) Using the eutectic solvent mixture as the organic electrolyte, the iron sheet as the anode and cathode, maintaining a stable system temperature, and providing continuous current input to form an organic electrolytic cell system;

[0010] (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and the anode are connected with current, the anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxide, the surfactant in the organic electrolyte derives an organic ligand, and the organic ligand is connected to the amino-type magnetic nano-iron oxide through the amino group to generate a ligand-type nano-magnetic particle unit in situ;

[0011] (5) Stop the current input, the electrolysis reaction ends, and after the electrolyte is subjected to mass-liquid separation, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness, and the aggregates are an amphiphilic magnetic responsive organic affinity adsorbent.

[0012] Preferably, in step (1), the quaternary ammonium salt choline comprises a mixture of one or more of choline chloride, betaine, phosphorylcholine and acetylcholine.

[0013] Preferably, in step (1), the molar ratio between one or both of the urea and thiourea and the quaternary ammonium salt choline is 1:(0.25-2); the molar ratio between urea and thiourea is 1:1; and the heating temperature is 85°C-140°C.

[0014] Preferably, the purity of the quaternary ammonium salt choline is above 80.0wt% by mass; the purity of the urea and thiourea is above 95.0wt%.

[0015] Preferably, in step (2), the surfactant has a long carbon chain structure without oxygen-containing highly electroactive groups such as carboxyl, ether or hydroxyl groups in chemical composition; the surfactant is one of a long-chain alkyl methyl ammonium bromide cationic surfactant, a polyvinyl pyrrolidone nonionic surfactant, a long-chain alkyl sulfate anionic surfactant, and a long-chain alkyl benzene sulfonate anionic surfactant; the mass concentration of the surfactant in the eutectic solvent mixture is 1 mg g -1 ~50mg g -1 .

[0016] Preferably, in step (2), the long-chain alkyl methyl ammonium bromide type cationic surfactant is hexadecyl trimethyl ammonium bromide or octadecyl trimethyl ammonium bromide; the polyvinyl pyrrolidone type nonionic surfactant is polyvinyl pyrrolidone; the long-chain alkyl sulfate type anionic surfactant is sodium dodecyl sulfate; the long-chain alkyl benzene sulfonate type anionic surfactant is sodium hexadecyl benzene sulfonate.

[0017] Preferably, in step (2), the polar organic solvent includes one or more mixed solvents selected from ethanol, methanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and pyridine; and the volume ratio between the eutectic solvent and the polar organic solvent is (1-36):3.

[0018] Preferably, in step (3), the purity of the iron sheet is 90wt% to 99.99wt%; a continuous direct current or pulse current input is provided, and the constant current density is 5mAcm -2 ~250mAcm -2 ; The system temperature is stable at 55℃~95℃.

[0019] In order to achieve the purpose of the invention, the present invention also provides an amphiphilic magnetic responsive organic affinity adsorbent prepared by the preparation method of the above-mentioned amphiphilic magnetic responsive organic affinity adsorbent. Through X-ray powder diffraction, vibrating sample magnetometer, dynamic light scattering technology, scanning electron microscope and isonitrogen temperature adsorption curve and other technical means analysis, it can be seen that the amphiphilic magnetic responsive organic affinity adsorbent prepared by the present invention has γ-Fe2O3 as the core, has ferrimagnetism and a saturation magnetization intensity of 20emu g -1 ~60emu g -1 ; The median particle size of the aqueous dispersion is 150nm to 1500nm; the specific surface area is 20m 2 g -1 ~200m 2 g -1 , has excellent adsorption performance.

[0020] In order to achieve the purpose of the invention, the present invention also provides the application of the above-mentioned amphiphilic magnetic-responsive organic affinity adsorbent, wherein the adsorbent is used for the purification of organically polluted water bodies, wherein the chemical oxygen demand value of the organically polluted water bodies is lower than 1000ppm; the organic pollutants contained in the organically polluted water bodies include antibiotics, organic dyes, purines, polycyclic aromatic hydrocarbons, organic pesticides, aliphatic hydrocarbons, micro-oil particles, and emulsions.

[0021] The present invention designs a technical route for the simultaneous generation of magnetic particle units and their ligandization, using a eutectic solvent-based organic solution containing a surfactant as an electrolyte, and adopting an organic electrolysis method to complete the generation of magnetic particles and their ligandization. By adjusting the type and concentration of the surfactant in the eutectic solvent-based organic electrolyte, the components and content of the liganded magnetic particle ligands are regulated, and the in-situ construction of the amphiphilic magnetic responsive adsorbent is completed in a self-assembly manner in combination with the phase transfer strategy. The surface of the amphiphilic magnetic responsive organic affinity adsorbent prepared by the present invention is in-situ modified with an amphiphilic organic affinity ligand derived from a surfactant, and the organic adsorbent in the liquid environment can be adsorbed and separated by affinity with the ligand, which can meet the requirements for the increasingly miniaturized, refined and precise treatment of organic polluted water bodies such as antibiotics, organic dyes, polycyclic aromatic hydrocarbons, organic pesticides, aliphatic hydrocarbons, micro-oil particles and persistent organic pollutants.

[0022] Compared with the prior art, the electrolytic generation of magnetic particles and their ligandization in the present invention are in situ, and the composition and content of ligands in the electrolytically generated liganded magnetic particles and amphiphilic magnetic responsive adsorbents can be regulated by adjusting the type and concentration of surfactants in the eutectic solvent-based organic electrolyte, thereby regulating the affinity speed and adsorption amount of the adsorbent, creating conditions for the controllable in situ construction of amphiphilic magnetic responsive adsorbents with strong affinity and high adsorption amount; the prepared adsorbent can efficiently adsorb and treat persistent pollutants in the liquid phase, and the adsorbent can be divided into three types: cationic, non-ionic and anionic according to the type of surfactant, thereby expanding the application field and applicable scenarios of the adsorbent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is an X-ray powder diffraction pattern of an amphiphilic magnetic responsive adsorbent, (a) is prepared in Example 1, (b) is prepared in Example 3, and (c) is prepared in Example 5;

[0024] Figure 2 : are magnetization curves of amphiphilic magnetic responsive adsorbents, (a) is prepared in Example 1, (b) is prepared in Example 3, and (c) is prepared in Example 5;

[0025] Figure 3 The dynamic light scattering particle size distribution diagram of the aqueous dispersion of the amphiphilic magnetic responsive adsorbent, (a) is prepared in Example 1, (b) is prepared in Example 3, and (c) is prepared in Example 5;

[0026] Figure 4 : isothermal adsorption curves of nitrogen gas of amphiphilic magnetic responsive adsorbents, (a) is prepared in Example 1, (b) is prepared in Example 3, and (c) is prepared in Example 5;

[0027] Figure 5 This is a scanning electron microscopic image of the cationic amphiphilic magnetic responsive adsorbent prepared in Example 3;

[0028] Figure 6 These are the effect diagrams of affinity adsorption test of the amphiphilic magnetic responsive adsorbents prepared in Example 1, Example 3, and Example 5, respectively, on the water-soluble microemulsified cutting oil-based aqueous emulsion. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0030] Example 1

[0031] A method for preparing an amphiphilic magnetically responsive organic affinity adsorbent comprises the following steps:

[0032] (1) mixing urea with a purity of 99.5 wt% and choline chloride with a purity of 99.0 wt% in a molar ratio of 1:2, and heating in a sealed container at 95° C. to obtain a colorless and transparent eutectic solvent;

[0033] (2) mixing the eutectic solvent and N,N-dimethylformamide in a volume ratio of 2:3, and then adding hexadecyltrimethylammonium bromide to obtain a eutectic solvent mixed solution; the mass concentration of the hexadecyltrimethylammonium bromide in the mixed solution is 15 mg g -1 ;

[0034] (3) The eutectic solvent mixture was used as the organic electrolyte, and iron sheets with a purity of 99.9 wt% were used as the anode and cathode. The system temperature was maintained at 75 °C and a continuous supply of 40 mA cm was provided. -2 Constant current input to form an organic electrolytic cell system;

[0035] (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and the anode are connected with current, the anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxide, the surfactant in the organic electrolyte derives an organic ligand, and the organic ligand is connected to the amino-type magnetic nano-iron oxide through the amino group to generate a ligand-type nano-magnetic particle unit in situ;

[0036] (5) Stop the current input, the electrolysis reaction ends, and after the electrolyte is subjected to mass-liquid separation, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness. An external magnetic field is used to assist solid-liquid separation and the mixture is washed with water to obtain a cationic amphiphilic magnetic responsive organic affinity adsorbent.

[0037] The cationic amphiphilic magnetic responsive adsorbent obtained by the above preparation method has the following physical and chemical characteristics: Figure 1 The X-ray powder diffraction spectrum can confirm that its phase structure is γ-Fe2O3. As can be seen from Table 1, the X-ray photoelectron spectrum shows that the ratio of nitrogen to iron is 0.215. Figure 2 The magnetization curve shows that its saturation magnetization is 48.7emu g -1 ,from Figure 3 The dynamic light scattering particle size distribution diagram shows that the median particle size of the aqueous dispersion is 295nm. Figure 4 The specific surface area calculated from the isothermal adsorption curve is 56.4 m 2 g -1 .

[0038] A cationic amphiphilic magnetic responsive adsorbent constructed by the above method is used to treat organic polluted water with a commercial water-soluble microemulsified cutting oil-based aqueous emulsion as the water body to be treated. The adsorbent dosage is 20 mg mL relative to the water volume. -1After affinity adsorption by the above adsorbent, it becomes clear and transparent within 3 minutes ( Figure 6 ); When COD was 337-641 and 1074, after affinity adsorption treatment, chemical oxygen demand (COD, mg L -1 or ppm, the same below) was reduced to 24-29 and 81 (Table 2), respectively reaching the first and second level standards for pollutant discharge from urban sewage treatment plants (GB18918-2002, the same below). Taking adenine as the representative of purine pollutants, the adsorbent dosage was 25 mg mL relative to the water volume. -1 When the COD was 431 and 766 respectively, the COD was reduced from 39 to 91 respectively after 8 minutes of affinity adsorption treatment with the above adsorbent.

[0039] Example 2

[0040] A method for preparing an amphiphilic magnetically responsive organic affinity adsorbent comprises the following steps:

[0041] (1) urea with a purity of 99.5 wt% and phosphorylcholine with a purity of 80.0 wt% were mixed in a molar ratio of 2:1, and heated in a sealed container at 140° C. to obtain a colorless and transparent eutectic solvent;

[0042] (2) mixing the eutectic solvent with a mixed solvent of N,N-dimethylformamide and methanol in a volume ratio of 12:1, wherein the volume ratio of N,N-dimethylformamide to methanol is 3:1; and then adding octadecyltrimethylammonium bromide to obtain a eutectic solvent mixed solution; the mass concentration of the hexadecyltrimethylammonium bromide in the eutectic solvent mixed solution is 50 mg g -1 ;

[0043] (3) The eutectic solvent mixture was used as the organic electrolyte, and iron sheets with a purity of 90.0 wt% were used as the anode and cathode. The system temperature was maintained at 55 °C and a continuous supply of 5 mA cm was provided. -2 Constant current input to form an organic electrolytic cell system;

[0044] (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and the anode are connected with current, the anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxide, the surfactant in the organic electrolyte derives an organic ligand, and the organic ligand is connected to the amino-type magnetic nano-iron oxide through the amino group to generate a ligand-type nano-magnetic particle unit in situ;

[0045] (5) Stop the current input, the electrolysis reaction ends, and after the electrolyte is subjected to mass-liquid separation, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness. An external magnetic field is used to assist solid-liquid separation and the mixture is washed with water to obtain a cationic amphiphilic magnetic responsive organic affinity adsorbent.

[0046] The cationic amphiphilic magnetic responsive adsorbent obtained by the above preparation method has the following physical and chemical characteristics: the phase structure is γ-Fe2O3, the nitrogen to iron content ratio is 0.277, the saturation magnetization intensity is 20emu g -1 The median particle size of the aqueous dispersion is 150 nm and the specific surface area is 200 m 2 g -1 .

[0047] A cationic amphiphilic magnetic responsive adsorbent constructed by the above method, with oxytetracycline, a broad-spectrum anti-pathogenic microorganism, as the simulated antibiotic pollutant, and the adsorbent dosage is 20 mg mL relative to the water volume -1 After 5 minutes of affinity adsorption treatment with the above adsorbent, the COD in the water decreased from 322-598 to 44-62.

[0048] Example 3

[0049] A method for preparing an amphiphilic magnetically responsive organic affinity adsorbent comprises the following steps:

[0050] (1) urea with a purity of 99.5 wt% and choline chloride with a purity of 80.0 wt% are mixed in a molar ratio of 1:2, and heated in a sealed container at 95° C. to obtain a colorless and transparent eutectic solvent;

[0051] (2) The eutectic solvent and N,N-dimethylformamide are mixed in a volume ratio of 2:3, and polyvinyl pyrrolidone is added to obtain a eutectic solvent mixed solution; the mass concentration of the polyvinyl pyrrolidone in the eutectic solvent mixed solution is 15 mg g -1 ;

[0052] (3) The eutectic solvent mixture was used as the organic electrolyte, and iron sheets with a purity of 99.9 wt% were used as the anode and cathode. The system temperature was maintained at 75 °C and a continuous supply of 40 mA cm was provided. -2 Constant current input to form an organic electrolytic cell system;

[0053] (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and the anode are connected with current, the anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxide, the surfactant in the organic electrolyte derives an organic ligand, and the organic ligand is connected to the amino-type magnetic nano-iron oxide through the amino group to generate a ligand-type nano-magnetic particle unit in situ;

[0054] (5) Stop the current input, the electrolysis reaction ends, and after the electrolyte is subjected to mass-liquid separation, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness. An external magnetic field is used to assist solid-liquid separation and the mixture is washed with water to obtain a non-ionic amphiphilic magnetic responsive organic affinity adsorbent.

[0055] The cationic amphiphilic magnetic responsive adsorbent obtained by the above preparation method is Figure 1 The X-ray powder diffraction spectrum can confirm that its physical structure is γ-Fe2O3. As can be seen from Table 1, the X-ray photoelectron spectrum shows that the ratio of nitrogen to iron is 0.272. Figure 2 The magnetization curve shows that its saturation magnetization is 46.6emu g -1 ,from Figure 3 The dynamic light scattering particle size distribution diagram shows that the median particle size of the aqueous dispersion is 246nm. Figure 4 The specific surface area calculated from the isothermal adsorption curve is 70.0 m 2 g -1 , Figure 5 The scanning electron micrograph shown shows that the average particle size is 107 ± 13 nm.

[0056] A nonionic amphiphilic magnetic responsive adsorbent constructed by the above method is used as a commercial water-soluble microemulsified cutting oil-based aqueous emulsion to be treated as the organic polluted water body, and the adsorbent dosage is 20 mg mL relative to the water volume. -1 After being adsorbed by the above adsorbent, it becomes clear and transparent within 5 minutes ( Figure 6 ); when COD was 337-641 and 1074, after affinity adsorption treatment, COD was reduced to 29-41 and 89 (Table 2), reaching the primary and secondary standards for pollutant discharge from urban sewage treatment plants, respectively. Anthracene and edible oil were used as polycyclic aromatic hydrocarbons and aliphatic hydrocarbons or micro-oil particles and dispersed in the water body. The adsorbent dosage was 20 mg mL relative to the water volume. -1 When their COD were 211 and 476, they were reduced to 27 and 62 respectively after 10 minutes of affinity adsorption treatment with the above adsorbent.

[0057] Example 4

[0058] A method for preparing an amphiphilic magnetically responsive organic affinity adsorbent comprises the following steps:

[0059] (1) a mixture of 98.5% pure phosphorylcholine and 98.0% pure acetylcholine in a molar ratio of 4:1 and 95.0wt% pure urea in a molar ratio of 1:4, and the mixture is heated in a sealed container at 85° C. to obtain a colorless and transparent eutectic solvent;

[0060] (2) mixing the eutectic solvent with a mixed solvent of N,N-dimethylformamide and ethanol in a volume ratio of 1:3, wherein the volume ratio of N,N-dimethylformamide to ethanol is 2:1; and then adding polyvinyl pyrrolidone to obtain a eutectic solvent mixed solution; the mass concentration of the polyvinyl pyrrolidone in the eutectic solvent mixed solution is 1 mg g -1;

[0061] (3) The eutectic solvent mixture was used as the organic electrolyte, and iron sheets with a purity of 99.9 wt% were used as the anode and cathode. The system temperature was maintained at 95 °C and a continuous supply of 250 mA cm was provided. -2 Constant current input to form an organic electrolytic cell system;

[0062] (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and the anode are connected with current, the anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxide, the surfactant in the organic electrolyte derives an organic ligand, and the organic ligand is connected to the amino-type magnetic nano-iron oxide through the amino group to generate a ligand-type nano-magnetic particle unit in situ;

[0063] (5) Stop the current input, the electrolysis reaction ends, and after the electrolyte is subjected to mass-liquid separation, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness. An external magnetic field is used to assist solid-liquid separation and the mixture is washed with water to obtain a non-ionic amphiphilic magnetic responsive organic affinity adsorbent.

[0064] The cationic amphiphilic magnetic responsive adsorbent obtained by the above preparation method has the following physical and chemical characteristics: the phase structure is γ-Fe2O3, the nitrogen to iron content ratio is 0.211, and the saturation magnetization intensity is 60.0emu g -1 The median particle size of the aqueous dispersion is 150 nm and the specific surface area is 20.0 m 2 g -1 .

[0065] A nonionic amphiphilic magnetic responsive adsorbent constructed by the above method, using water-soluble dye Rhodamine B as a simulated dye pollutant, and the adsorbent dosage is 25 mg mL relative to the water volume -1 After 10 minutes of affinity adsorption treatment with the above adsorbent, the COD in the water decreased from 409-617 to 47-69.

[0066] Example 5

[0067] A method for preparing an amphiphilic magnetically responsive organic affinity adsorbent comprises the following steps:

[0068] (1) urea with a purity of 99.5 wt% and choline chloride with a purity of 80.0 wt% are mixed in a molar ratio of 1:2, and heated in a sealed container at 95° C. to obtain a colorless and transparent eutectic solvent;

[0069] (2) mixing the eutectic solvent and N,N-dimethylformamide in a volume ratio of 2:3, and then adding sodium dodecyl sulfate to obtain a eutectic solvent mixed solution; the mass concentration of the sodium dodecyl sulfate in the eutectic solvent mixed solution is 15 mg g -1 ;

[0070] (3) The eutectic solvent mixture was used as the organic electrolyte, and iron sheets with a purity of 99.9 wt% were used as the anode and cathode. The system temperature was maintained at 75 °C and a continuous supply of 40 mA cm was provided. -2 Constant current input to form an organic electrolytic cell system;

[0071] (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and the anode are connected with current, the anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxide, the surfactant in the organic electrolyte derives an organic ligand, and the organic ligand is connected to the amino-type magnetic nano-iron oxide through the amino group to generate a ligand-type nano-magnetic particle unit in situ;

[0072] (5) Stop the current input, the electrolysis reaction ends, and after the electrolyte is subjected to mass-liquid separation, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness. An external magnetic field is used to assist solid-liquid separation and then washed with water to obtain an anionic amphiphilic magnetic responsive organic affinity adsorbent.

[0073] The cationic amphiphilic magnetic responsive adsorbent obtained by the above preparation method is Figure 1 The X-ray powder diffraction spectrum can confirm that its physical structure is γ-Fe2O3. As can be seen from Table 1, the X-ray photoelectron spectrum shows that the nitrogen to iron content ratio is 0.353, and the sulfur content is 3.38atom%. Figure 2 The magnetization curve shows that its saturation magnetization is 47.5emu g -1 ,from Figure 3 The dynamic light scattering particle size distribution diagram shows that the median particle size of the aqueous dispersion is 196nm. Figure 4 The specific surface area calculated from the isothermal adsorption curve is 97.0 m 2 g -1 .

[0074] A cationic amphiphilic magnetic responsive adsorbent constructed by the above method is used to treat organic polluted water with a commercial water-soluble microemulsified cutting oil-based aqueous emulsion as the water body to be treated. The adsorbent dosage is 20 mg mL relative to the water volume. -1 After being adsorbed by the above adsorbent, it becomes clear and transparent within 5 minutes ( Figure 6 ); COD decreased from 337-641 and 1074 to 37-47 and 95 (Table 2), reaching the first and second level standards for pollutant discharge from urban sewage treatment plants, respectively.

[0075] Example 6

[0076] A method for preparing an amphiphilic magnetically responsive organic affinity adsorbent comprises the following steps:

[0077] (1) a mixture of urea and thiourea with a purity of 99.5 wt% and betaine with a purity of 98.0 wt% were mixed in a molar ratio of 2:1, the molar ratio of urea to thiourea being 1:1, and heated in a sealed manner at 120° C. to obtain a colorless and transparent eutectic solvent;

[0078] (2) mixing the eutectic solvent with a mixed solvent of dimethyl sulfoxide and pyridine in a volume ratio of 1:3, wherein the volume ratio of dimethyl sulfoxide to pyridine is 9:1, and then adding sodium hexadecylbenzenesulfonate to obtain a eutectic solvent mixed solution; the mass concentration of the sodium hexadecylbenzenesulfonate in the eutectic solvent mixed solution is 25 mg g -1 ;

[0079] (3) The eutectic solvent mixture was used as the organic electrolyte, and iron sheets with a purity of 90.0 wt% were used as the anode and cathode. The system temperature was maintained at 65 °C and a continuous supply of 125 mA cm was provided. -2 Constant current input to form an organic electrolytic cell system;

[0080] (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and the anode are connected with current, the anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxide, the surfactant in the organic electrolyte derives an organic ligand, and the organic ligand is connected to the amino-type magnetic nano-iron oxide through the amino group to generate a ligand-type nano-magnetic particle unit in situ;

[0081] (5) Stop the current input, the electrolysis reaction ends, and after the electrolyte is subjected to mass-liquid separation, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness. An external magnetic field is used to assist solid-liquid separation and then washed with water to obtain an anionic amphiphilic magnetic responsive organic affinity adsorbent.

[0082] The cationic amphiphilic magnetic responsive adsorbent obtained by the above preparation method has the following physical and chemical characteristics: the phase structure is γ-Fe2O3, the nitrogen to iron content ratio is 0.278, the sulfur content is 4.57atom%, and the saturation magnetization intensity is 33.9emu g -1 The median particle size of the aqueous dispersion is 224 nm and the specific surface area is 85.3 m 2 g -1 .

[0083] A cationic amphiphilic magnetic responsive adsorbent constructed by the above method is used to treat organic polluted water with a commercial water-soluble microemulsified cutting oil-based aqueous emulsion as the water body to be treated. The adsorbent dosage is 20 mg mL relative to the water volume. -1When the COD was 355-622 and 982, the COD was reduced to 25-43 and 83 after affinity adsorption, reaching the primary and secondary standards of urban sewage treatment plant pollutant discharge, respectively. Glyphosate monoammonium salt, glyphosate diammonium salt and glyphosate triammonium salt were used as representatives to simulate the organic pesticide water pollution system, and the adsorbent dosage was 25 mg mL relative to the water volume. -1 After 10 minutes of affinity adsorption treatment with the above adsorbent, the detected concentrations of the above three glycyrrhizinate ammonium salts in water were reduced from 30 mg / mL to 4 mg / mL, 3 mg / mL and 1 mg / mL.

[0084] Table 1 X-ray photoelectron spectroscopy elemental analysis of amphiphilic magnetic responsive adsorbent (atom%)

[0085]

[0086] Table 2 COD values ​​of water-soluble microemulsified cutting oil-based aqueous emulsion before and after treatment with amphiphilic magnetic responsive adsorbent

[0087]

Claims

1. A method for preparing an amphiphilic magnetically responsive organic affinity adsorbent, characterized in that: The following steps are involved: (1) Mixing one or both of urea and thiourea with quaternary ammonium salt choline in a certain proportion, and heating in a sealed state to obtain a eutectic solvent; (2) mixing the eutectic solvent obtained in step (1) with a polar organic solvent in a certain volume ratio, and then adding a surfactant to obtain a eutectic solvent mixed solution; the surfactant is one of a long-chain alkyl methyl ammonium bromide type cationic surfactant, a polyvinyl pyrrolidone type nonionic surfactant, a long-chain alkyl sulfate type anionic surfactant, and a long-chain alkyl benzene sulfonate type anionic surfactant; (3) Using the eutectic solvent mixture as the organic electrolyte and the iron sheets as the anode and cathode, the system temperature was maintained at a stable level of 55°C to 95°C, and a continuous current input was provided with a constant current density of 5 mA cm -2 ~250mA cm -2 , constituting an organic electrolytic cell system; (4) Under stirring conditions, an organic electrolysis reaction is carried out after the cathode and anode currents are turned on. The anode iron atoms are stripped and oxidized to amino-type magnetic nano-iron oxides. The surfactant in the organic electrolyte derives organic ligands. The organic ligands are connected to the amino-type magnetic nano-iron oxides through the amino groups to generate ligand-type nano-magnetic particle units in situ. (5) Stop the current input, the electrolysis reaction ends, and after mass-liquid separation of the entire electrolyte, the separated liganded nanomagnetic particle units are transferred to water. The liganded nanomagnetic particle units self-assemble into submicron aggregates with magnetic responsiveness. The aggregates are an amphiphilic magnetic responsive organic affinity adsorbent.

2. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 1, characterized in that: In step (1), the quaternary ammonium choline salt includes one or more mixtures of choline chloride, betaine, choline phosphate, and acetylcholine.

3. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 1 or 2, characterized in that: In step (1), the molar ratio of one or both of the urea and thiourea to the quaternary ammonium salt choline is 1:(0.25-2); and the heating temperature is 85°C-140°C.

4. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 3, characterized in that: In step (1), the molar ratio between urea and thiourea is 1:

1.

5. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 1, characterized in that: In step (1), the purity of the quaternary ammonium salt of choline is greater than 80.0 wt% by mass; the purity of the urea and thiourea is greater than 95.0 wt%.

6. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 1 or 2, characterized in that: In step (2), the mass concentration of the surfactant in the eutectic solvent mixture is 1 mg g -1 ~50mg g -1 .

7. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 6, characterized in that: In step (2), the long-chain alkyl methyl ammonium bromide type cationic surfactant is hexadecyl trimethyl ammonium bromide or octadecyl trimethyl ammonium bromide; the polyvinyl pyrrolidone type nonionic surfactant is polyvinyl pyrrolidone; the long-chain alkyl sulfate type anionic surfactant is sodium dodecyl sulfate; the long-chain alkyl benzene sulfonate type anionic surfactant is sodium hexadecyl benzene sulfonate.

8. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 1 or 2, characterized in that: In step (2), the polar organic solvent includes one or more mixed solvents selected from ethanol, methanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and pyridine; and the volume ratio between the eutectic solvent and the polar organic solvent is (1-36):

3.

9. The method for preparing an amphiphilic magnetically responsive organic affinity adsorbent according to claim 1 or 2, characterized in that: In step (3), the purity of the iron sheet is 90wt% to 99.99wt%; and a continuous direct current or pulse current input is supplied.

10. An amphiphilic magnetically responsive organic affinity adsorbent prepared by the preparation method of an amphiphilic magnetically responsive organic affinity adsorbent as described in any one of claims 1 to 9.

11. A use of the amphiphilic magnetically responsive organic affinity adsorbent as claimed in claim 10, characterized in that: The adsorbent is used for purifying organically polluted water bodies, the chemical oxygen demand value of which is lower than 1000 ppm; the organic pollutants contained in the organically polluted water bodies include antibiotics, organic dyes, purines, organic pesticides, micro-oil particles, and emulsions.

12. A use of the amphiphilic magnetically responsive organic affinity adsorbent as claimed in claim 10, characterized in that: The adsorbent is used for purification of organically polluted water bodies, the chemical oxygen demand value of which is lower than 1000 ppm; the organic pollutants contained in the organically polluted water bodies include polycyclic aromatic hydrocarbons and aliphatic hydrocarbons.

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