Method for synthesizing green nano-iron from pomegranate leaf extract

Abstract

The invention discloses a method for synthesizing green nano-iron from pomegranate leaf extract, the synthesis of nano-iron is realized by mixing the pomegranate leaf extract and an iron salt solution, and the method comprises the following steps: firstly, weighing a certain amount of cleaned and dried pomegranate leaves, adding the pomegranate leaves into a three-neck flask, and adding a certain amount of deionized water; placing in a water bath at a certain temperature, heating for a period of time, cooling to room temperature, and filtering to obtain the pomegranate leaf extracting solution. In addition, preparing a ferric salt solution with a certain concentration; mixing the ferric salt solution and the pomegranate leaf extract according to a certain proportion, and fully stirring for reaction; and carrying out centrifugal separation on the reacted solution to successfully obtain green nano-iron particles. The invention solves the problems of complex conditions and difficult stable production in the common nano-iron synthesis process, and provides a method for synthesizing green nano-iron.

Description

Technical Field

[0001] The invention belongs to the field of environmentally friendly green materials, and particularly relates to a method for synthesizing green iron nanoparticles from pomegranate leaf extract. Background Art

[0002] In recent years, nanoparticles have been widely used as adsorption and degradation materials in the field of water treatment due to their small particle size and large specific surface area. The traditional preparation methods of iron nanoparticles are mainly prepared by Fe(CO)5 thermal decomposition method or NaBH4 reduction method. These methods are costly, energy-intensive, and require special reaction equipment. At the same time, they also produce environmentally unfriendly byproducts. Therefore, it is urgent to seek a low-cost and environmentally friendly synthesis method. Based on the concept of green chemistry, the study of using biodegradable substances, such as plant extracts, to prepare nano iron particles has become a research hotspot. Green synthesis does not use chemical reducing agents, but natural plant extracts. Compared with chemical and physical synthesis methods, plant extract synthesis has the advantages of low cost, environmental protection, no need for high temperature and high pressure, and no toxic chemicals in the synthesis process. Studies have shown that polyphenols rich in plant extracts can not only be used as reducing agents, but also as stabilizers for green synthesis of nano iron particles. This method is simple, easy, low-cost, and environmentally friendly. Therefore, the use of green methods to make iron nanoparticles has attracted much attention. Through green synthesis, the cost is low, there are no byproducts, and the application prospects are bright. In view of the defects of the above iron nanoparticles and their synthesis methods, this study uses plant extracts as raw materials and a new biosynthesis method to prepare iron nanoparticles. The iron nanoparticles synthesized by this method can have a good adsorption effect on various pollutants in dye wastewater. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a method for synthesizing green iron nanoparticles from pomegranate leaf extract.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for synthesizing iron nanoparticles by mixing pomegranate leaf extract and iron salt solution, and the specific steps are as follows:

[0006] A method for synthesizing green iron nanoparticles from pomegranate leaf extract, comprising the following steps:

[0007] (1) Preparation of pomegranate leaf extract

[0008] Wash the pomegranate leaves, remove the dust on them, put them in an oven to dry at a certain temperature until the weight remains unchanged, weigh a certain amount of pomegranate leaves, and then put them into a crusher for crushing, transfer the crushed leaf debris into a three-necked flask, and put a magnet in it, heat and stir in a water bath at a certain temperature, remove the water bath heating after a certain period of time, cool to room temperature, centrifuge and filter, and the filtrate after filtration is the pomegranate leaf extract;

[0009] (2) Preparation of iron salt solution: quantitatively weighing iron salt solid using an analytical balance, stirring with deionized water to dissolve it, and obtaining an iron salt solution of a certain concentration; the iron salt is one of ferric chloride, ferric nitrate, ferric sulfate or ferric phosphate;

[0010] (3) Preparation of iron nanoparticles from pomegranate leaf extract: The iron salt solution obtained above is added to the pomegranate leaf extract. Stirring is performed continuously during the pouring process. The volume ratio of the iron salt solution to the pomegranate leaf extract is 1:(1-4). After sufficient reaction, the obtained solid is washed to obtain nano-iron particles.

[0011] Beneficial effects of the present invention: The present invention obtains extracts from pomegranate leaves directly from easily available leaves in a one-step method, adds an iron salt solution under continuous stirring conditions, and separates by centrifugal filtration to obtain iron nanoparticles that can only be obtained under traditional high temperature and high pressure conditions. Compared with other green synthetic nanoparticles, first, this method has a short synthesis path and can be synthesized in one step. Second, this method does not require the addition of additional substances, only pomegranate leaf extract and iron salt are required, which can save raw materials when used, and can also avoid secondary pollution problems that may be caused by other chemical substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the XRD diagram of the iron nanoparticles synthesized in the present invention. The iron nanoparticles have no Fe0 characteristic diffraction peak at 2θ=44.9°, and only one broad hump appears at 2θ=25°, indicating that the synthesized iron nanoparticles are all amorphous non-crystalline structures;

[0013] Figure 2 This is a SEM image of the iron nanoparticles synthesized in the present invention. The surface of the iron nanoparticles presents an irregular spherical structure that is agglomerated together, and the particle size distribution is 30-40nm;

[0014] Figure 3 This is the EDS image of the iron nanoparticles synthesized in the present invention. It is found that the obtained FeNPs are mainly composed of C, O, Fe, and P elements, while the contents of S, N, and Cl elements are relatively low. The contents of C, O, and Fe elements in the iron nanoparticles are 53.01%, 34.44%, and 9.96%;

[0015] Figure 4is a Zeta potential diagram of the iron nanoparticles synthesized in the present invention, indicating that when the pH range is 2.0 to 12.0, the surface of the iron nanoparticles is negatively charged;

[0016] Figure 5 This is the XPS spectrum of the iron nanoparticles synthesized in the present invention. There is no Fe 2p peak at the binding energy of 706.0 eV, indicating that there is no Fe0 in FeNPs. The peaks of Fe 2p near 710 eV and 712 eV correspond to the characteristic peaks of Fe(II) and Fe(III), respectively, and the peak near 714 eV is the satellite peak corresponding to Fe(II);

[0017] Figure 6 This is a diagram showing the adsorption effect of malachite green on the iron nanoparticles synthesized in the present invention;

[0018] Figure 7 This is a diagram showing the adsorption effect of the iron nanoparticles synthesized in the present invention on methylene blue. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited thereto.

[0020] The invention discloses a method for synthesizing green nano-iron from pomegranate leaf extract. The synthesis of nano-iron is achieved by mixing pomegranate leaf extract and iron salt solution. The steps are as follows: first, a certain amount of washed and dried pomegranate leaves are weighed, added into a three-necked flask, and a certain amount of deionized water is added. The leaves are placed in a water bath at a certain temperature, heated for a period of time, cooled to room temperature, and then filtered to obtain a pomegranate leaf extract. In addition, a FeCl3 solution of a certain concentration is prepared. The FeCl3 solution and the pomegranate leaf extract are mixed in a certain ratio, and the mixture is fully stirred for reaction. The solution after the reaction is centrifuged to successfully obtain green nano-iron particles.

[0021] The specific processing is as follows:

[0022] Example 1

[0023] A method for synthesizing green nano-iron from pomegranate leaf extract, comprising the following steps:

[0024] (1) Preparation of pomegranate leaf extract: Wash the pomegranate leaves, remove the dust on them, put them in an oven to dry for 3-5 days until the weight remains unchanged and the temperature is maintained at 30-50°C, put them in a sealed bag and set aside. In order to facilitate the subsequent water bath heating, 18,000 grams of pomegranate leaves were weighed with an analytical balance, then placed in a crusher, and 150 ml of deionized water was added in batches for quantitative grinding. When all the materials are crushed, pour them into a 250 ml three-necked flask, put in a magnet, place it in a water bath at 70-95°C, heat for 40-70 minutes, and then cool to room temperature. For easy filtration, centrifuge separation is used. After filtration, pomegranate leaf extract is obtained. The filtered liquid must be sealed and stored at low temperature and placed in a refrigerator;

[0025] (2) Preparation of iron salt solution: 0.1448 g of FeCl3·6H2O solid was accurately weighed using an electronic analytical balance and stirred with 20.00 mL of deionized water to dissolve the solid. The concentration of iron in the iron salt was 1500 mg / L.

[0026] (3) Preparation of nano iron particles from pomegranate leaf extract: Add the FeCl3 solution obtained above to the pomegranate leaf extract, stir at high speed, and keep the volume ratio of the iron solution to the pomegranate leaf extract at 1:1. The detailed operation steps are: use a pipette to transfer 10 mL of the pomegranate leaf extract to a beaker with a magnet, then add 10 mL of the iron salt solution to the beaker, the solution immediately changes from yellow to black, stir and react for 1 hour, and then wash the fully reacted iron nanoparticles. Put 5 mL of the iron nanoparticle mixture into a centrifuge tube, centrifuge at a speed of 1000-5000 rpm, and wash with deionized water 2-3 times. After separation in a centrifuge and three rinses with deionized water, the material in the centrifuge tube is dispersed into a certain amount of deionized water to obtain nano iron particles of a certain concentration. Nano iron particles can also be treated with ultrasonic equipment.

[0027] The nano iron particles obtained in Example 1 were tested, and the results were as follows: Figure 1-7 As shown, Figure 1 The iron nanoparticles have no Fe0 characteristic diffraction peak at 2θ=44.9°, and only a broad hump appears at 2θ=25°, indicating that the synthesized iron nanoparticles are all amorphous and non-crystalline structures. Figure 2 The surface of the iron nanoparticles presents an irregular spherical structure that is aggregated together, and the particle size distribution is 30-40nm. Figure 3 The FeNPs of medium nano-iron particles are mainly composed of C, O, Fe, and P elements, while the contents of S, N, and Cl elements are relatively low. The contents of C, O, and Fe elements in the iron nanoparticles are 53.01%, 34.44%, and 9.96%, respectively. Figure 4The Zeta potential diagram of the nano-iron particles shows that the surface of the iron nano-particles is negatively charged when the pH changes from 2.0 to 12.0. Figure 5 In the figure, there is no Fe 2p peak at the binding energy of 706.0 eV, indicating that there is no Fe0 in FeNPs. The peaks of Fe 2p near 710 eV and 712 eV correspond to the characteristic peaks of Fe(II) and Fe(III), respectively, and the peak near 714 eV is the satellite peak corresponding to Fe(II). Test 1: Adsorption of malachite green dye by nano-iron particles

[0028] The concentration is 200 mg·L -1 The malachite green solution was mixed with the above iron nanoparticle solution (25 mg Fe·L -1 ) were mixed at room temperature and at 300 r·min -1 The mixture was stirred at a speed of 100 °C and samples were taken at 1, 5, 10, 20, 30, 45 and 60 min, and a 0.45 μm filter membrane was used for solid-liquid separation. The absorbance was measured at the maximum absorption wavelength of malachite green using a UV-visible spectrophotometer. Figure 6 As shown. The adsorption performance of iron nanoparticles on malachite green reaches 80% after 1 minute; the reaction reaches equilibrium after 20 minutes, and the removal rate of malachite green is 90.5%. Test 2: Adsorption of methylene blue dye by nano-iron particles

[0029] The concentration is 200 mg·L -1 The methylene blue solution was mixed with the above iron nanoparticle solution (25 mg Fe·L -1 ) were mixed at room temperature and at 300 r·min -1 The mixture was stirred at a speed of 100 °C and samples were taken at 1, 5, 10, 20 and 30 min, and solid-liquid separation was performed using a 0.45 μm filter membrane. The absorbance was measured at the maximum absorption wavelength of methylene blue using a UV-visible spectrophotometer, and the remaining methylene blue concentration in the solution was calculated. Figure 7 As shown in the figure, the adsorption performance of iron nanoparticles on methylene blue reaches a reaction rate of 70.3% after 1 minute, and the reaction reaches equilibrium after 20 minutes, at which time the removal rate of methylene blue is 89.2%.

[0030] Example 2

[0031] A method for synthesizing green nano-iron from pomegranate leaf extract, comprising the following steps:

[0032] (1) crushing dry pomegranate leaves and adding water, wherein the mass ratio of the dry pomegranate leaves to water is 1:17, heating and stirring in a water bath at 95° C. for 70 minutes, cooling and centrifuging to obtain a filtrate as a pomegranate leaf extract;

[0033] (2) dissolving the iron salt ferric phosphate in water and stirring to obtain an iron salt solution, wherein the concentration of the iron salt solution is 1500 mg / L;

[0034] (3) Pour the iron salt solution into the pomegranate leaf extract, stir during the dropwise addition, the volume ratio of the iron salt solution to the pomegranate leaf extract is 1:4, and after reacting for 3 hours, wash the obtained solid to obtain nano iron particles.

[0035] Example 3

[0036] A method for synthesizing green nano-iron from pomegranate leaf extract, comprising the following steps:

[0037] (1) crushing dry pomegranate leaves and adding water, wherein the mass ratio of the dry pomegranate leaves to water is 1:12, heating and stirring in a water bath at 80° C. for 60 minutes, cooling and centrifuging to obtain a filtrate as a pomegranate leaf extract;

[0038] (2) dissolving ferric sulfate in water and stirring to obtain an iron salt solution, wherein the concentration of the iron salt solution is 1000 mg / L;

[0039] (3) Pour the iron salt solution into the pomegranate leaf extract and stir during the dropwise addition. The volume ratio of the iron salt solution to the pomegranate leaf extract is 1:2. After reacting for 2 hours, wash the obtained solid to obtain nano-iron particles.

[0040] Example 4

[0041] A method for synthesizing green nano-iron from pomegranate leaf extract, comprising the following steps:

[0042] (1) crushing dry pomegranate leaves and adding water, wherein the mass ratio of the dry pomegranate leaves to water is 1:8, heating and stirring in a water bath at 70° C. for 40 minutes, cooling and centrifuging to obtain a filtrate as a pomegranate leaf extract;

[0043] (2) dissolving ferric nitrate in water and stirring to obtain an iron salt solution, wherein the concentration of the iron salt solution is 500 mg / L;

[0044] (3) Pour the iron salt solution into the pomegranate leaf extract and stir during the dropwise addition. The volume ratio of the iron salt solution to the pomegranate leaf extract is 1:3. After reacting for 1 hour, wash the obtained solid to obtain nano-iron particles.

Claims

1. A method for synthesizing green nano-iron from pomegranate leaf extract, wherein the characteristic steps are as follows: (1) crushing the dried pomegranate leaves and adding water, wherein the mass ratio of the dried pomegranate leaves to the water is 1:(8-17), heating and stirring in a water bath at 70-95° C. for 40-70 minutes, cooling and centrifuging to obtain a filtrate as a pomegranate leaf extract; (2) dissolving an iron salt in water and stirring to obtain an iron salt solution, wherein the concentration of the iron salt solution is 500-1500 mg / L; (3) Pour the iron salt solution into the pomegranate leaf extract and stir during the addition. The volume ratio of the iron salt solution to the pomegranate leaf extract is 1:(1-4). After reacting for 1-3 hours, wash the obtained solid to obtain nano-iron particles.

2. The method for synthesizing green nano-iron from pomegranate leaf extract according to claim 1, characterized in that: The dried pomegranate leaves in step (1) are leaves of ordinary pomegranate trees, and the green leaves of the pomegranate tree are naturally air-dried or dried at low temperature to obtain the dried pomegranate leaves.

3. The method for synthesizing green nano-iron from pomegranate leaf extract according to claim 1, characterized in that: The iron salt in step (2) is one of ferric chloride, ferric nitrate, ferric sulfate or ferric phosphate.

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