Preparation method and application of PEI modified magnetic nano silicon oxide material

Abstract

The invention provides PEI (polyethyleneimine) functional modification based on magnetic nano silicon oxide and a preparation method and application thereof, and belongs to the field of organic-inorganic composite adsorption materials. The invention provides PEI modification based on magnetic nano silicon oxide. The PEI modification comprises the following raw material components in percentage by mass: magnetic ferroferric oxide, ethyl orthosilicate, APTES (3-aminopropyltriethoxysilane), glutaraldehyde (50%) and PEI. The preparation method comprises the following steps: firstly coating the surface of magnetic ferroferric oxide with nano silicon oxide, then introducing amino of APTES, and finally grafting PEI on the surface of the material by taking glutaraldehyde as a cross-linking agent. The PEI modified magnetic nano silicon oxide material provided by the invention can remarkably improve the adsorption effect on acid dye acid lake blue A, and is convenient to recycle due to magnetism.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of organic-inorganic composite adsorption materials, and particularly relates to preparation and application of PEI modified nano-silicon oxide material. BACKGROUND

[0002] Dyes have been widely used by humans in various industries for more than a thousand years, and dye wastewater is the main source of industrial wastewater, which has attracted high attention from the society. The presence of dyes in water bodies may cause the oxygen content of the water bodies to decrease and the sunlight transmission to become poor, affecting the photosynthesis of aquatic organisms. In addition, most dyes are carcinogenic, mutagenic or teratogenic to animals and humans, and a large number of reports have proved that various malignant tumors, reproductive system and central nervous system functional disorders, dermatitis, and asthma can be induced by dyes. In recent years, people have invented various methods for removing dyes, and the currently mature methods mainly include physical methods (filtration, adsorption, membrane separation), chemical methods (coagulation, oxidation), and biological methods (aerobic / anaerobic biological treatment, microbial degradation). Compared with other methods, the adsorption method has a long history, a wide source of materials, a high removal rate, and a renewable adsorbent. Common adsorbents include activated carbon, biomass, clay minerals, ion exchange resins, and metal organic frameworks. Nano-silicon oxide material is a new type of inorganic material developed gradually in the 1990s, and has a regular pore and adjustable pore size, and is widely used in the fields of catalysis, electrochemistry, and adsorption. Compared with other adsorbents, nano-silicon oxide has a larger specific surface area, a high adsorption capacity, and stable chemical properties, and is resistant to acid and alkali and high temperature. The surface of the nano-silicon oxide can be grafted with functional groups (such as thiol and amino groups) to optimize the adsorption activity and selectively adsorb polar dyes (such as acid and basic dyes). SUMMARY

[0003] The application provides a preparation method and application of PEI modified magnetic nano-silicon oxide material, and aims to solve the problems of poor adsorption efficiency of existing adsorbents for acid lake blue A dye and low utilization rate of adsorbents. In a first aspect, the application provides a PEI modified magnetic nano-silicon oxide material, which comprises magnetic nano-silicon oxide, APTES, and PEI grafted onto the magnetic nano-silicon oxide. In a second aspect, the application provides a preparation method of the PEI modified magnetic nano-silicon oxide material, which comprises the following steps: (1) mixing dispersed ferroferric oxide and tetraethyl orthosilicate for reaction for 24 hours, filtering, washing, and drying, mixing the obtained Fe3O4@SiO2 and APTES for reaction for 24 hours, filtering, washing, and drying to obtain Fe3O4@SiO2-NH2. (2) mixing the obtained Fe3O4@SiO2-NH2 in step (1) with glutaraldehyde and PEI for reaction for 4 hours, filtering, washing, and drying. Preferably, the mass-volume ratio of Fe3O4, tetraethyl orthosilicate and water in step (1) is 1g:5ml:20ml, and the mass-volume ratio of Fe3O4@SiO2 and APTES is 1g:5ml. Preferably, the solvent required for the preparation of Fe3O4@SiO2 in step (1) is ethanol, the mass-volume ratio of Fe3O4, tetraethyl orthosilicate, water and solvent ethanol is 1g:5ml:20ml:60ml, and the solvent required for the preparation of Fe3O4@SiO2-NH2 material is ethanol, the mass-volume ratio of Fe3O4@SiO2, APTES and solvent ethanol is 1g:5ml:80ml. Preferably, the reaction temperature in step (1) is room temperature. Preferably, the washing step in the preparation of the material in step (1) is repeated three times with anhydrous ethanol and water, and the drying process is 12h at 60℃. Preferably, the mass-volume ratio of Fe3O4@SiO2-NH2, glutaraldehyde and PEI in step (2) is 1:0.6:1. Preferably, the solvent required for the preparation of Fe3O4@SiO2-PEI in step (2) is water, the mass-volume ratio of Fe3O4@SiO2-NH2, glutaraldehyde, PEI and solvent water is 1g:0.6g:1g:30ml. Preferably, the reaction temperature in step (2) is 40℃. Preferably, the washing step in the preparation of the material in step (2) is repeated three times with anhydrous ethanol and water, and the drying process is 4h at 40℃. The application provides a PEI modified magnetic nano-silicon oxide material, which effectively improves the structure and performance of nano-silicon oxide and improves the adsorption efficiency of acid blue lake A. Compared with the prior art, the application has the following beneficial effects: (1) The adsorption efficiency of acid blue lake A is significantly improved. (2) The preparation method of the PEI modified magnetic nano-silicon oxide material is simple, efficient, low in cost and easy to realize industrialization. BRIEF DESCRIPTION OF DRAWINGS Figure 1 It is a Fourier infrared spectrum of the PEI modified magnetic nano-silicon oxide material; Figure 2 It is a graph of adsorption removal efficiency changing with the amount of adsorbent; Figure 3 It is a graph of adsorption removal efficiency changing with adsorption time; Figure 4is the adsorption removal efficiency with pH change graph. DETAILED DESCRIPTION In order to solve the problem of poor adsorption performance of existing adsorbents on acid blue A dye, the application provides a PEI modified magnetic nano silicon oxide material preparation and application. Among them, APTES is first grafted onto the magnetic nano silicon oxide, and then PEI is grafted onto the magnetic nano silicon oxide through Schiff base reaction of aldehyde group and amino group, so that the adsorption capacity of acid blue A dye is improved, and recycling can be used. The application will be further described below in conjunction with specific examples. It should be understood that these examples are exemplary and are only used to explain the application and do not mean to limit the application. The test method is not specified in the following examples. Generally, the conventional conditions are used, and the instruments involved are commercially available products. Example 1 The Fe3O4@SiO2 material is prepared, and the specific steps are as follows: Fe3O4 1g is dispersed in a solution composed of 20ml water and 60ml ethanol, and ultrasonic dispersion is performed for 30min. Then ammonia water (1ml) is added dropwise while stirring, and stirring is continued for 30min. 5ml TEOS (tetraethyl orthosilicate) is added in batches, and stirring is continued at room temperature for 24h. After the reaction is completed, the sample is washed repeatedly with anhydrous ethanol and water for 3 times, and the remaining reactants are removed. The sample is dried at 60°C under vacuum for 12h. Fe3O4@SiO2 is obtained. The Fe3O4@SiO2-NH2 material is prepared, and the specific steps are as follows: Fe3O4@SiO2 1g is dispersed in 80ml anhydrous ethanol, 5ml APTES solution is added, and stirring reaction is performed at room temperature for 24h. Then the sample is washed repeatedly with anhydrous ethanol and water for 3 times, and dried at 60°C for 12h. The Fe3O4@SiO2-PEI material is prepared, and the specific steps are as follows: Fe3O4@SiO2-NH2 1g is suspended in 30ml water, the pH is adjusted to 8, and then 0.6g glutaraldehyde and 1g PEI are added into the suspension. Heating is performed at 40°C for 4h, and finally the sample is washed repeatedly with ethanol and water for 3 times, and dried at 40°C for 12h. The PEI modified magnetic nano silicon oxide material prepared in Example 1 is subjected to Fourier infrared characterization, and the results are shown in Figure 1 . Figure 1 The infrared characterization results of the PEI modified magnetic nano silicon oxide material are shown in the figure. As can be seen from the figure, Si-O-Si, C=N and NH2 are respectively located at 1095, 1610 and 3450cm (-1) , which indicates that PEI is successfully grafted onto the magnetic nano silicon oxide. Performance test The PEI modified magnetic nano-silicon oxide material prepared in Example 1 was used as an adsorbent to test the adsorption of acid blue A dye, and the specific operation steps were as follows: 1. Adsorption effect under different amounts: 0.01, 0.015, 0.02, 0.025, and 0.03 g of the obtained material were used to adsorb 100 ml of 20 mg / l acid blue A solution under the same pH and time, constant temperature oscillation, and adsorption. 2. Adsorption effect under different times: 100 ml of 20 mg / l acid blue A solution was adsorbed for 20, 40, 60, 80, and 100 min under the same adsorbent dosage and pH. 3. Adsorption effect under different pH: 100 ml of 20 mg / l acid blue A solution with pH = 2, 3, 4, 5, 6, 7, 8, and 9 was adsorbed under the same adsorbent dosage and adsorption time. Figure 2 The results reflect the different adsorption removal rates under different adsorbent dosages. Compared with Fe3O4@SiO2 material, Fe3O4@SiO2-PEI has a higher removal rate, with a maximum removal rate of 68%. Both materials reach adsorption equilibrium when the adsorbent dosage is 0.02 g. Figure 3 The results reflect the different adsorption removal rates under different adsorption times. Again, Fe3O4@SiO2-PEI has a higher removal rate, and both materials reach equilibrium at 60 min. Figure 4 The results reflect the adsorption efficiency under different pH. Both materials have the highest adsorption efficiency at pH = 4.

Claims

1. A PEI-modified magnetic nano-silica material, characterized in that... This includes nano-silica coated with magnetic iron oxide, APTES covalently condensed with magnetic nano-silica, PEI introduced through Schiff base reaction between aldehyde and amino groups, and glutaraldehyde providing aldehyde groups.

2. The method for preparing PEI-modified magnetic nano-silica material as described in claim 1, characterized in that, Includes the following steps: Dispersed iron oxide was mixed with tetraethyl orthosilicate and water, reacted for 24 h, washed, and dried. The resulting sample was mixed with APTES, reacted for 24 h, washed, and dried. Finally, it was mixed with glutaraldehyde and PEI, reacted at 40 °C for 4 h, washed, and dried to obtain the PEI-modified magnetic nano-silica material.

3. The method for preparing PEI-modified magnetic nano-silica material as described in claim 2, characterized in that... The mass-to-volume ratio of Fe3O4@SiO2 to tetraethyl orthosilicate and water is 1g:5ml:20ml, the mass-to-volume ratio of Fe3O4@SiO2 to APTES is 1g:5ml, and the mass-to-volume ratio of Fe3O4@SiO2-NH2 to glutaraldehyde and PEI is 1:0.6:

1.

4. The method for preparing PEI-modified magnetic nano-silica material as described in claim 2, characterized in that, The solvent required for preparing Fe3O4@SiO2 material is ethanol, the solvent required for preparing Fe3O4@SiO2-NH2 material is ethanol, and the solvent required for preparing Fe3O4@SiO2-PEI is water.

5. The method for preparing PEI-modified magnetic nano-silica material as described in claim 2, characterized in that, The mass-volume ratio of Fe3O4@SiO2, APTES, and ethanol is 1g:5ml:60ml:20ml; the mass-volume ratio of Fe3O4@SiO2-NH2, glutaraldehyde, PEI, and water is 1g:0.6g:1g:30ml.

6. The method for preparing PEI-modified magnetic nano-silica material as described in claim 2, characterized in that, When preparing Fe3O4@SiO2 material, ammonia water should be added dropwise while stirring to keep the pH in the range of 7-8. The preparation of Fe3O4@SiO2-PEI requires a solution pH of 8.

7. The method for preparing PEI-modified magnetic nano-silica material as described in claim 2, characterized in that, All washing steps involved repeated washing with anhydrous ethanol and water three times. The drying steps for preparing Fe3O4@SiO2 and Fe3O4@SiO2-NH2 were performed at 60℃ for 12 hours, while the drying steps for preparing Fe3O4@SiO2-PEI were performed at 40℃ for 12 hours.

8. The application of the PEI-modified magnetic nano-silica material as described in claim 1 in the adsorption of Acid Lake Blue A dye.

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