An amino magnetic gel, its preparation method and application

Abstract

The present invention provides an amino magnetic gel, a preparation method thereof and an application thereof, belonging to the technical field of magnetic gels. In the present invention, nano-ferroferric oxide is dispersed in water, and then sodium silicate and tetraethyl orthosilicate are respectively added to modify the nano-ferroferric oxide to obtain modified nano-ferroferric oxide; the modified nano-ferroferric oxide and epichlorohydrin are dispersed in N,N-dimethylformamide for reaction to obtain a gel precursor; an amine source is added to the gel precursor for reaction to obtain an amino magnetic gel. The present invention has the advantages of simple preparation process, controllable particle size and surface groups of the magnetic gel, etc. A gel network with a controllable thickness is formed on the surface of the magnetic nanospheres by the amino gel, which not only improves the dispersibility of the amino gel, but also effectively removes heavy metal ions and dye molecules.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic gels, and in particular to an amino magnetic gel and its preparation method and application. Background Art

[0002] In recent years, the treatment of industrial wastewater has attracted increasing attention. There are a large number of toxic and harmful substances in industrial wastewater, such as dye molecules, heavy metal particles, etc., which have a certain impact on people's lives. At present, methods for removing heavy metal ions include chemical precipitation, ultrafiltration, adsorption, ion exchange, reverse osmosis, electrodialysis, and biological methods. Among them, the adsorption method is widely used in the removal of heavy metal ions in industry due to its advantages such as low cost, high efficiency, and easy operation.

[0003] Magnetic gel adsorbents have the characteristics of being magnetic and convenient for recycling, and easy surface functionalization, etc., with significant advantages. When used as an adsorbent to separate heavy metal ions and dye molecules, due to its unique superparamagnetism and network structure, the contact area between the adsorbent and the target substance is increased, and it is also convenient for separation and recycling. At present, it occupies an extremely important position in the fields of medicine, catalysis, energy storage, drug carriers, etc.

[0004] However, the current preparation method of magnetic gels is cumbersome, and the adsorption performance for heavy metal ions and dye molecules is not good. Therefore, how to obtain a magnetic gel with good adsorption effect for adsorbing heavy metal ions and dye molecules is a technical problem that needs to be solved at present. Summary of the Invention

[0005] The purpose of the present invention is to provide an amino magnetic gel and its preparation method and application, which are used to solve the technical problems of cumbersome preparation and poor adsorption performance of existing magnetic gels.

[0006] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of an amino magnetic gel, comprising the following steps:

[0008] 1) Dispersing nano-ferroferric oxide in water, and then adding sodium silicate and tetraethyl orthosilicate respectively to modify the nano-ferroferric oxide to obtain modified nano-ferroferric oxide;

[0009] 2) Reacting the modified nano-ferroferric oxide and epichlorohydrin in N,N-dimethylformamide to obtain a gel precursor;

[0010] 3) Adding an amine source to the gel precursor for reaction to obtain an amino magnetic gel.

[0011] Furthermore, the dosage ratio of the nano-ferroferric oxide, sodium silicate and water is 1-10 g: 1-20 g: 1-10 mL, and the mass ratio of tetraethyl orthosilicate and nano-ferroferric oxide is 0.1-0.5: 1-10.

[0012] Furthermore, in the step 1), before adding tetraethyl orthosilicate, anhydrous ethanol is added first and ultrasonic dispersion is carried out for 10-30 min.

[0013] Furthermore, the volume ratio of water and anhydrous ethanol is 1: 2-4.

[0014] Furthermore, the dosage ratio of the modified nano-ferroferric oxide, epichlorohydrin and N, N-dimethylformamide is 5-20 g: 1-10 g: 20-40 mL.

[0015] Furthermore, in the step 2), the reaction temperature is 60-90 °C and the reaction time is 1-2 h.

[0016] Furthermore, the amine source includes one or more of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, polyethyleneimine, diethylenetriamine and tetraethylenepentamine;

[0017] The mass ratio of the amine source and epichlorohydrin is 1-10: 1-10.

[0018] Furthermore, in the step 3), the reaction temperature is 60-90 °C and the reaction time is 1-2 h.

[0019] The present invention also provides an amino magnetic gel.

[0020] The present invention also provides an application of the amino magnetic gel in adsorbing heavy metal ions and dye molecules.

[0021] The beneficial effects of the present invention:

[0022] (1) The preparation process of the amino magnetic gel of the present invention does not require special atmosphere protection and does not require post-treatment before use. It has good saturation magnetization intensity and the surface functional groups are easy to regulate.

[0023] (2) The amino magnetic gel of the present invention has a simple preparation process, is easy to industrialize, the gel network structure on the surface is controllable, and it has excellent adsorption performance for both Cr(VI) and MO at the same time, which provides help for the removal of heavy metal ions and dye molecules in industrial wastewater.

[0024] (3) The amino magnetic gel of the present invention has excellent saturation magnetization intensity, has a high separation and enrichment speed, and the separation efficiency exceeds 99% within 5 minutes. The amino magnetic gel of the present invention has a large specific surface area and rich porosity, so as to provide more active adsorption sites during adsorption. Description of the Drawings

[0025] Figure 1 It is the saturation magnetization intensity curve graph of the amino magnetic gel synthesized in Example 1 of the present invention;

[0026] Figure 2 It is the adsorption kinetic curve graph of the amino magnetic gel synthesized in Example 1 of the present invention for MO. Detailed Description of the Invention

[0027] The present invention provides a preparation method of an amino magnetic gel, comprising the following steps:

[0028] 1) Disperse nano-ferroferric oxide in water, and then add sodium silicate and tetraethyl orthosilicate to modify the nano-ferroferric oxide to obtain modified nano-ferroferric oxide;

[0029] 2) Disperse the modified nano-ferroferric oxide and epichlorohydrin in N,N-dimethylformamide for reaction to obtain a gel precursor;

[0030] 3) Add an amine source to the gel precursor for reaction to obtain an amino magnetic gel.

[0031] In the present invention, the preparation method of the nano-ferroferric oxide comprises the following method:

[0032] Synthesis by co-precipitation method: Using ferric chloride hexahydrate and ferrous chloride tetrahydrate as precursors, ammonia water as a catalyst, and deionized water as a solvent, nano-ferroferric oxide is prepared by co-precipitation method at 30-80 °C, wherein the dosage ratio of ferric chloride hexahydrate, ferrous chloride tetrahydrate, ammonia water and deionized water is 1-20 g: 1-10 g: 1-10 mL: 40-100 mL, preferably 5-15 g: 2-8 g: 2-8 mL: 50-80 mL.

[0033] Synthesis by solvothermal method: Using ferric chloride hexahydrate as a precursor, polyethylene glycol as a dispersant, sodium acetate anhydrous as a precipitant, and ethylene glycol as a solvent, nano-ferroferric oxide is prepared by solvothermal method at 160-180 °C, wherein the mass ratio of ferric chloride hexahydrate, polyethylene glycol, sodium acetate anhydrous and ethylene glycol is 1-10: 1-20: 10-30: 40-100, preferably 2-8: 5-15: 15-25: 50-80.

[0034] In the present invention, the dosage ratio of the nano-ferroferric oxide, sodium silicate and water is 1-10 g: 1-20 g: 1-10 mL, preferably 2-8 g: 5-15 g: 2-8 mL, and further preferably 5 g: 10 g: 5 mL.

[0035] In the present invention, the mass ratio of tetraethyl orthosilicate to nano-ferroferric oxide is 0.1-0.5:1-10, preferably 0.2-0.4:2-8, and more preferably 0.3:4-6.

[0036] In the present invention, after adding sodium silicate, the pH of the system is adjusted to 9.0 with hydrochloric acid having a concentration of 0.1-0.3 mol / L, preferably hydrochloric acid with a concentration of 0.1 mol / L.

[0037] In the present invention, in step 1), before adding tetraethyl orthosilicate, anhydrous ethanol is first added and ultrasonic dispersion is carried out for 10-30 min, preferably 20 min.

[0038] In the present invention, the volume ratio of water to anhydrous ethanol is 1:2-4, preferably 1:3.

[0039] In the present invention, the dosage ratio of the modified nano-ferroferric oxide, epichlorohydrin and N,N-dimethylformamide is 5-20 g:1-10 g:20-40 mL, preferably 10-15 g:2-8 g:30 mL, and more preferably 10 g:5 g:30 mL.

[0040] In the present invention, in step 2), the reaction temperature is 60-90 °C, preferably 65-85 °C, and more preferably 70-80 °C; the reaction time is 1-2 h, preferably 2 h.

[0041] In the present invention, the amine source includes one or more of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, polyethyleneimine, diethylenetriamine and tetraethylenepentamine, preferably one or more of ethylenediamine, propylenediamine and tetraethylenepentamine.

[0042] In the present invention, the mass ratio of the amine source to epichlorohydrin is 1-10:1-10, preferably 2-8:2-8, and more preferably 4-6:4-6.

[0043] In the present invention, in step 3), the reaction temperature is 60-90 °C, preferably 65-85 °C, and more preferably 70-80 °C; the reaction time is 1-2 h, preferably 2 h.

[0044] The present invention also provides an amino magnetic gel.

[0045] In the present invention, the particle size of the amino magnetic gel is 1-50 μm, preferably 5-40 μm, as measured according to ISO13320; the pore size ≤200 nm, preferably ≤50 nm, as measured according to ISO 15901-3.

[0046] In the present invention, the specific surface area of the amino magnetic gel is 20-1000 m2 / g, preferably 100 - 800 m 2 / g, measured according to ISO 9277.

[0047] In the present invention, the saturation magnetization intensity of the amino magnetic gel is 1 - 10 emu / g, and the amino magnetic gel has superparamagnetism.

[0048] The present invention also provides an application of the amino magnetic gel in adsorbing heavy metal ions and dye molecules.

[0049] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Preparation of nano - Fe₃O₄ magnetic core:

[0051] Coprecipitation method: 1.0 g of ferrous chloride tetrahydrate and 2.7 g of ferric chloride hexahydrate were dispersed in 50 mL of deionized water, stirred at 60 °C for 30 min, then 5 mL of concentrated ammonia water was added, the temperature was adjusted to 80 °C and stirred for 4.0 h. After the reaction ended, nano - Fe₃O₄ (N1) was obtained.

[0052] Solvothermal method: 1.36 g of ferric chloride hexahydrate and 3.0 g of polyethylene glycol 4000 were added to 50.0 g of ethylene glycol, stirred at 90 °C for 60 min, then 10.0 g of anhydrous sodium acetate was added, the temperature was adjusted to 180 °C and stirred for 24 h. After the reaction ended, nano - Fe₃O₄ (N2) was obtained.

[0053] Example 1

[0054] 1.0 g of N1 was dispersed in 20 mL of deionized water, 5.0 g of sodium silicate was added, and then the pH value of the system was adjusted to 9.0 with 0.1 mol / L hydrochloric acid, followed by ultrasonic treatment for 30 min. Then, 60 mL of absolute ethanol was added, and ultrasonic treatment was continued for 30 min. Finally, 0.2 g of tetraethyl orthosilicate was added and stirred at room temperature for 4.0 h to obtain modified nano - Fe₃O₄.

[0055] 5.0 g of the modified magnetic core N1 and 6.0 g of epichlorohydrin were dispersed in 30 mL of N,N - dimethylformamide solution, stirred at 80 °C for 1.0 h, and then 4.0 g of ethylenediamine was added dropwise and the reaction continued for 1.0 h. After the reaction ended, an amino magnetic gel was obtained.

[0056] Example 2

[0057] Same as Example 1, except that the magnetic core used was N2.

[0058] Example 3

[0059] Same as Example 1, except that the amine source of ethylenediamine is replaced by butanediamine.

[0060] Example 4

[0061] Same as Example 3, except that the magnetic core used is N2.

[0062] Example 5

[0063] Same as Example 1, except that the amine source of ethylenediamine is replaced by hexanediamine.

[0064] Example 6

[0065] Same as Example 5, except that the magnetic core used is N2.

[0066] Example 7

[0067] Same as Example 1, except that the amine source of ethylenediamine is replaced by polyethyleneimine.

[0068] Example 8

[0069] Same as Example 7, except that the magnetic core used is N2.

[0070] Example 9

[0071] Same as Example 1, except that the amine source of ethylenediamine is replaced by triethylenetetramine.

[0072] Example 10

[0073] Same as Example 9, except that the magnetic core used is N2.

[0074] Example 11

[0075] Same as Example 1, except that the amine source of ethylenediamine is replaced by tetraethylenepentamine.

[0076] Example 12

[0077] Same as Example 11, except that the magnetic core used is N2.

[0078] Adsorption kinetics experiment:

[0079] Study on the adsorption performance of adsorbent for Cr(VI) and methyl orange (MO) under different time conditions. The pH value of 100 mg / L Cr(VI) / MO solution was adjusted to 2 with 5 mol / L HCl solution. The volume of the solution was 300 ml, and 30 mg of adsorbent was added. After shaking in a constant temperature water bath oscillator for a period of time, the upper layer liquid was extracted and the concentration was calculated by ultraviolet spectrophotometer. For Cr(VI), according to the national standard GB7467-87, the residual Cr(VI) concentration after adsorption was measured by ultraviolet spectrophotometer, and the adsorption capacity and removal rate were calculated. For methyl orange (MO) dye, a series of standard solutions were first prepared, then the absorbance was measured at its maximum absorption peak, and finally the standard curve was fitted according to Beer's law. Finally, the residual MO concentration after adsorption was determined according to the standard curve, and the adsorption capacity and removal rate were calculated. The Cr(VI) / MO in the residual liquid was tested at regular intervals, and the test results are shown in Table 1.

[0080] Table 1 Adsorption performance results

[0081]

[0082] As can be seen from the above examples, the present invention provides an amino magnetic gel and its preparation method and application. It can be seen from Table 1 above that the amino magnetic gel has excellent adsorption performance for both Cr(VI) and MO, and the adsorption effect is the best when ethylenediamine is used as the amine source; Figure 1 is the saturation magnetization intensity curve of the amino magnetic gel. It can be seen that the amino magnetic gel has superparamagnetism, and the saturation magnetization intensity is 15 emu / g, which provides a basis for later recycling and recovery; Figure 2 is the adsorption kinetic curve of the amino magnetic gel for MO. It can be seen that the adsorption rate of the amino magnetic gel for MO is relatively fast, and the adsorption equilibrium can be reached in about 10 minutes, and it has the potential to be used as a rapid adsorbent. The amino magnetic gel of the present invention has excellent saturation magnetization intensity, a high separation and enrichment speed, and the separation efficiency exceeds 99% within 5 minutes. The amino magnetic gel of the present invention has a large specific surface area and rich porosity, thus providing more active adsorption sites during adsorption.

[0083] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of amino magnetic gel, characterized in that It includes the following steps: 1) Dispersing nano-ferroferric oxide in water, and then adding sodium silicate and tetraethyl orthosilicate respectively to modify the nano-ferroferric oxide to obtain modified nano-ferroferric oxide; 2) Dispersing the modified nano-ferroferric oxide and epichlorohydrin in N,N-dimethylformamide for reaction to obtain a gel precursor; 3) Adding an amine source to the gel precursor for reaction to obtain an amino magnetic gel; The dosage ratio of the nano-ferroferric oxide, sodium silicate and water is 1-10 g: 1-20 g: 1-10 mL, and the mass ratio of tetraethyl orthosilicate and nano-ferroferric oxide is 0.1-0.5: 1-10; In the step 2), the reaction temperature is 60-90 °C and the reaction time is 1-2 h; In the step 3), the reaction temperature is 60-90 °C and the reaction time is 1-2 h; The amino magnetic gel is used for adsorbing heavy metal ions and dye molecules; The dosage ratio of the modified nano-ferroferric oxide, epichlorohydrin and N,N-dimethylformamide is 5-20 g: 1-10 g: 20-40 mL; The amine source includes one or more of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, polyethyleneimine, diethylenetriamine and tetraethylenepentamine; The mass ratio of the amine source and epichlorohydrin is 1-10: 1-10.

2. The preparation method of the amino magnetic gel according to claim 1, characterized in that, In the step 1), before adding tetraethyl orthosilicate, anhydrous ethanol is added and ultrasonic dispersion is carried out for 10-30 min.

3. The preparation method of the amino magnetic gel according to claim 1 or 2, characterized in that, The volume ratio of the water and anhydrous ethanol is 1: 2-4.

4. The amino magnetic gel prepared by the preparation method according to any one of claims 1 to 3.

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