Method for synthesizing Fe3O4 nano oil removal material from bamboo leaf extract, Fe3O4 nano oil removal material and application of Fe3O4 nano oil removal material

Abstract

The invention discloses a method for synthesizing a Fe3O4 nano oil removal material from a bamboo leaf extract, the Fe3O4 nano oil removal material and application of the Fe3O4 nano oil removal material. The method comprises the following steps: heating, stirring, centrifuging and filtering to obtain the bamboo leaf extract, and synthesizing Fe3O4NPs by using the bamboo leaf extract as a stabilizer and an end-capping reagent; collecting a black precipitate, and then cleaning and drying the black precipitate to obtain Fe3O4NPs powder; preliminary characterization results show that the average particle size of the Fe3O4NPs is 12.54 nm, the Fe3O4NPs is in an irregular spherical shape, the stability is good, and the Fe3O4NPs has superparamagnetism; an oil removal experiment shows that under the optimal treatment conditions, namely the concentration is 400 mg / L, the temperature is 40 DEG C, the treatment time is 20 min, and the stirring speed is 200 rpm, the oil removal rate of Fe3O4 NPs is as high as 91.98%, and an excellent oil removal effect is achieved.

Description

Technical Field

[0001] This invention relates to the field of oily wastewater treatment technology, specifically to a method for synthesizing Fe3O4 nano-oil-removing material from bamboo leaf extract, and the application of Fe3O4 nano-oil-removing material. Background Technology

[0002] Oily wastewater comes from many sources, such as oil refineries, oil transportation, distribution, storage facilities, petrochemicals, textiles and leather, and metal manufacturing. It contains toxic substances such as hydrocarbons, polycyclic aromatic hydrocarbons, and phenols, which can pose a serious threat to global water resources, human health, and the environment. Nowadays, oily wastewater treatment technology is receiving increasing attention, and therefore, oily wastewater treatment has become an urgent problem to be solved.

[0003] For example, Chinese invention patent application number CN202311136807.3 discloses a method for low-temperature one-step synthesis of strongly magnetic hydrophobic 30 nanoparticles and the application of Fe3O4 nanoparticles, belonging to the field of nanomaterial preparation technology. The method includes: adding ferrous sulfate solution to a mixed solution of sodium hydroxide and sodium nitrate, heating and stirring the reaction, adding oleic acid during the reaction, and obtaining black Fe3O4 crystals after the reaction. The resulting strongly magnetic hydrophobic Fe3O4 nanoparticles have a saturation magnetization of up to 85.69 emu / g and a water contact angle of up to 148.95°.

[0004] For example, Chinese invention patent application number CN201110142469.5 discloses a method for preparing magnetic Fe3O4 nanoparticles and their application in the adsorption and separation of heavy metal ions. The method uses a hydrothermal synthesis method with water as the solvent. First, an aqueous solution of ferric chloride is prepared, and then ascorbic acid is added to obtain a solution. Hydrazine hydrate is added to the obtained solution, and then the solution is transferred to a stainless steel reactor to react. After the reaction is completed, the mixture is centrifuged, and the obtained precipitate is washed and dried to obtain magnetic Fe3O4 nanoparticles.

[0005] For example, Chinese invention patent application number CN202510174102.3 discloses a magnetic nanocomposite adsorbent, its preparation method, and its application. The preparation method includes the following steps: dissolving divalent and trivalent ferric salts in water, adding ammonia under a protective gas atmosphere, and stirring the mixture at 350 rpm-600 rpm to obtain Fe3O4 nanoparticles; dispersing the Fe3O4 nanoparticles in a mixed solution of acrylic acid and ethylenediamine, adding an initiator, and stirring the mixture at 150 rpm-300 rpm to obtain the magnetic nanocomposite adsorbent.

[0006] Traditional technologies for oil removal from oily wastewater include gravity separation, air flotation, and coagulation sedimentation, which typically require multi-stage processes, resulting in complex procedures and difficulty in achieving efficient, low-consumption, and environmentally friendly oil removal. Currently, oily wastewater treatment technology is receiving widespread attention, and exploring a green, sustainable, and highly efficient oil removal technology is a challenge facing the petroleum industry. Based on the aforementioned technical problems of existing technologies, this invention provides a method for synthesizing Fe3O4 nano-oil removal materials from bamboo leaf extract, as well as the application of Fe3O4 nano-oil removal materials. Summary of the Invention

[0007] To address the aforementioned technical problems in the existing technology, this invention provides a method for synthesizing Fe3O4 nano-oil-removing materials from bamboo leaf extract, as well as the application of Fe3O4 nano-oil-removing materials for treating oily wastewater generated in industry. The method utilizes adsorption at the oil-water interface, through the functional groups in bamboo leaves (such as -COOH, -C=O, -CHO, etc.) and Fe... 2+ or Fe 3+ Oil pollution can be treated by interacting with oily substances through complexation, hydrogen bonding, electrostatic interactions, or chemical bonds, thereby reducing the pollution of water resources by oil.

[0008] The present invention adopts the following technical solution:

[0009] This invention provides a method for synthesizing Fe3O4 nano-oil-removing materials from bamboo leaf extract, comprising:

[0010] Step 1: Weigh 10g of bamboo leaf powder and place it in a 100mL vial. Add 90mL of deionized water and mix. Place the vial in a rotor and heat and stir at 80℃ and 660rpm for 30min. Cool to room temperature and centrifuge at 8000rpm for 20min. Take the supernatant and filter it through a 0.45μm filter membrane to obtain bamboo leaf extract.

[0011] Step 2: Weigh 0.5g of analytical grade FeCl2·4H2O and 1.35g of analytical grade FeCl3·6H2O into a 50mL vial, with a molar ratio of FeCl2·4H2O to FeCl3·6H2O of 1:2. Place the rotor in the vial, cap it, and insert a needle into the stopper. Heat and stir the vial at 80℃ and 660rpm for 30min. Use a syringe to inject 10mL of the bamboo leaf extract obtained in Step 1 into the vial, and immediately add 1.5mL of analytical grade 2-acrylamide-2-methylpropanesulfonic acid (AMPS). Then add 2mL of NH3·H2O to adjust the pH of the mixed solution to 11, and continue stirring at 80℃ and 660rpm for 1h.

[0012] Step 3: After the mixed solution obtained in Step 2 is cooled to room temperature, the black precipitate is collected with a magnet, washed three times with deionized water, ultrasonically dispersed for 10 minutes, and then dried using a vacuum freeze dryer to obtain Fe3O4NPs powder.

[0013] Furthermore, the bamboo leaf powder in step 1 is dried bamboo leaf powder that has been pulverized and passed through a 100-mesh sieve.

[0014] Furthermore, the mass fraction of the 2 mL NH3·H2O added in step 2 is 25%~28%.

[0015] Furthermore, in step 3, the black precipitate is washed three times with deionized water, with 25 ml of deionized water added each time, and centrifuged at 8000 rpm for 15 min; the washed black precipitate is ultrasonicated using a Jingfei Technology ultrasonic disruptor at a temperature of 60°C and a power of 60%; and the ultrasonicated black precipitate is freeze-dried under vacuum conditions using a Xinzhi-12N freeze dryer.

[0016] This invention also provides a Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract, comprising:

[0017] Fe3O4NPs were synthesized using bamboo leaf extract as a reducing agent, stabilizer, and capping agent. The average particle size of the Fe3O4 nano-oil degreasing material is 8-20 nm, and the morphology is irregular spherical. In the X-ray diffraction pattern, diffraction peaks are observed at 30.2°, 35.6°, 43.2°, 53.7°, 57.2°, and 62.9°, which correspond to the (220), (311), (400), (422), (511), and (440) crystal planes of cubic Fe3O4, respectively. No other impurities are present. The Fe3O4 nano-oil degreasing material has superparamagnetism and a saturation magnetization of 52.21 emu / g.

[0018] Furthermore, the absolute value of the Zeta potential of the Fe3O4NPs is not less than 30mV, preferably -32.5mV.

[0019] Furthermore, the Fe3O4 nano-oil degreasing material has organic functional groups from bamboo leaf extract coated on its surface, including -COOH, -C=O, and -CHO.

[0020] This invention also provides an application of Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract, including:

[0021] The Fe3O4NPs oil removal material was added to the oily wastewater, and the concentration of Fe3O4NPs was controlled at 400 mg / L. The mixture was heated and stirred at 40℃ and 200 rpm for 20 min. After the mixture was cooled to room temperature in a cooling box, Fe3O4NPs were separated by a magnet to obtain the treated wastewater.

[0022] Furthermore, the oil content of the oily wastewater is 50~500mg / L; after treatment, the oil removal rate is ≥90%, and the separated Fe3O4NPs are reused after being washed with deionized water and vacuum dried.

[0023] Compared with the prior art, the superior effects of the present invention are as follows:

[0024] 1. The method for synthesizing Fe3O4 nano-oil removal material from bamboo leaf extract according to the present invention involves synthesizing Fe3O4NPs using bamboo leaf extract as a capping agent, stabilizer, and reducing agent. The Fe3O4NPs exhibit a spherical structure with an average particle size of 12.54 nm, good stability, a saturation magnetization of 52.21 emu / g, and superparamagnetism. Rapid separation is achieved through an external magnetic field, resulting in efficient oil removal.

[0025] 2. The method for synthesizing Fe3O4 nano-oil-removing materials from bamboo leaf extract described in this invention relies on the high specific surface area and abundant surface active sites of Fe3O4 NPs, which give it a strong ability to adsorb oily substances. Simultaneously, the abundant functional groups in the plant extract can not only bind with Fe... 2+ or Fe 3+ Complexation can also form a coating layer on the surface of NPs and interact with oily substances through hydrogen bonds, electrostatic interactions or chemical bonds, thereby improving the adsorption capacity of oil stains.

[0026] 3. The method for synthesizing Fe3O4 nano-oil removal material from bamboo leaf extract described in this invention achieves an oil removal rate of ≥90% under optimal conditions, which is significantly superior to traditional gravity separation and air flotation methods. Moreover, it does not require multi-stage processing and can directly and efficiently treat oily wastewater. Relying on the high specific surface area of ​​Fe3O4NPs and the synergistic adsorption effect of the surface functional groups of bamboo leaf extract, it can form hydrogen bonds, electrostatic interactions, or chemical bonds with oil stains, and has a stable treatment effect on wastewater with different oil contents. Its application scope covers multiple scenarios such as industrial oily wastewater.

[0027] 4. The method for synthesizing Fe3O4 nano-oil-removing materials from bamboo leaf extract described in this invention has a Zeta potential of -32.5mV for Fe3O4NPs, which far exceeds the stability threshold of ±30mV. This makes them less prone to aggregation and allows them to maintain dispersibility over a long period, ensuring a stable and consistent oil-removing effect. Furthermore, the single crystal form and uniform particle size of Fe3O4 materials result in a more controllable and repeatable treatment effect compared to existing Fe3O4 materials that are prone to aggregation and have mixed crystal forms.

[0028] 5. The method for synthesizing Fe3O4 nano-oil-removing materials from bamboo leaf extract described in this invention does not require complex equipment such as high-pressure reactors. It can be prepared simply by conventional heating, stirring, and magnetic separation. The process is simplified and safe to operate. Compared with traditional processes such as hydrothermal synthesis, it lowers the threshold for industrial production. The key parameters are clear and controllable, avoiding product performance fluctuations caused by complex processes in existing technologies, and facilitating large-scale mass production. Attached Figure Description

[0029] Figure 1 This is a flowchart of the method for synthesizing Fe3O4 nano-oil-removing material from bamboo leaf extract according to the embodiments of the present invention;

[0030] Figure 2 This is the FTIR spectrum of Fe3O4NPs synthesized from bamboo leaf extract described in the embodiments of the present invention;

[0031] Figure 3 This is the Zeta potential result of the synthesis of Fe3O4NPs from the bamboo leaf extract described in the embodiments of the present invention;

[0032] Figure 4 These are SEM and TEM images of Fe3O4NPs synthesized from bamboo leaf extract according to the embodiments of the present invention;

[0033] Figure 5 This is the XRD pattern of Fe3O4NPs synthesized from bamboo leaf extract described in the embodiments of the present invention;

[0034] Figure 6 This is the hysteresis loop of the bamboo leaf extract used in the embodiments of the present invention for synthesizing Fe3O4NPs;

[0035] Figure 7 This is a comparison of wastewater treatment before and after using Fe3O4NPs synthesized from bamboo leaf extract as described in the embodiments of the present invention. Detailed Implementation

[0036] To better understand the above-mentioned objectives, features and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0037] Example 1

[0038] like Figure 1 As shown, the method for synthesizing Fe3O4 nano-oil-removing material from bamboo leaf extract includes:

[0039] Step 1: Weigh 10g of bamboo leaf powder and place it in a 100mL vial. Add 90mL of deionized water and mix. Place the vial in a rotor and heat and stir at 80℃ and 660rpm for 30min. Cool to room temperature and centrifuge at 8000rpm for 20min. Take the supernatant and filter it through a 0.45μm filter membrane to obtain bamboo leaf extract.

[0040] Step 2: Weigh 0.5g of analytical grade FeCl2·4H2O and 1.35g of analytical grade FeCl3·6H2O into a 50mL vial, with a molar ratio of FeCl2·4H2O to FeCl3·6H2O of 1:2. Place the rotor in the vial, cap it, and insert a needle into the stopper. Heat and stir the vial at 80℃ and 660rpm for 30min. Then, inject 10mL of bamboo leaf extract obtained in Step 1 into the vial using a syringe, and immediately add 1.5mL of analytical grade 2-acrylamide-2-methylpropanesulfonic acid (AMPS). Add 2mL of NH3·H2O to adjust the pH of the mixed solution to 11, and continue stirring at 80℃ and 660rpm for 1h.

[0041] Step 3: After the mixed solution obtained in Step 2 is cooled to room temperature, the black precipitate is collected with a magnet, washed three times with deionized water, ultrasonically dispersed for 10 minutes, and then dried using a vacuum freeze dryer to obtain Fe3O4NPs powder.

[0042] In some specific instances, the bamboo leaf powder in step 1 is dried bamboo leaf powder that has been pulverized and passed through a 100-mesh sieve.

[0043] In some specific instances, the mass fraction of the 2 mL NH3·H2O added in step 2 is 25%~28%.

[0044] In some specific examples, in step 3, the black precipitate is washed three times with deionized water, with 25 ml of deionized water added each time, and centrifuged at 8000 rpm for 15 min; the washed black precipitate is ultrasonicated using a Jingfei Technology ultrasonic disruptor at a temperature of 60°C and a power of 60%; and the ultrasonicated black precipitate is freeze-dried under vacuum conditions using a Xinzhi-12N freeze dryer.

[0045] This invention also provides a Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract. The Fe3O4 nano-oil-removing material is prepared by the method described in any of the preceding claims, comprising:

[0046] Fe3O4NPs were synthesized using bamboo leaf extract as a reducing agent, stabilizer, and capping agent. The average particle size of the Fe3O4 nano-oil degreasing material is 8-20 nm, and the morphology is irregular spherical. In the X-ray diffraction pattern, diffraction peaks are observed at 30.2°, 35.6°, 43.2°, 53.7°, 57.2°, and 62.9°, which correspond to the (220), (311), (400), (422), (511), and (440) crystal planes of cubic Fe3O4, respectively. No other impurities are present. The Fe3O4 nano-oil degreasing material has superparamagnetism and a saturation magnetization of 52.21 emu / g.

[0047] In some specific instances, the absolute value of the Zeta potential of the Fe3O4NPs is not less than 30mV, preferably -32.5mV.

[0048] In some specific examples, the Fe3O4 nano-oil degreasing material is coated with organic functional groups from bamboo leaf extract, including -COOH, -C=O, and -CHO.

[0049] This invention also provides an application of Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract, including:

[0050] The Fe3O4NPs oil removal material was added to oily wastewater at a concentration of 200 mg / L, and the concentration of Fe3O4NPs was controlled at 400 mg / L. The mixture was heated and stirred at 40℃ and 200 rpm for 20 min. After cooling the mixture to room temperature in a cooling box, the Fe3O4NPs were separated using a magnetic block to obtain the treated wastewater. The oil content of the oily wastewater was 50~500 mg / L. After treatment, the oil removal rate was ≥90%, and the separated Fe3O4NPs could be reused after washing with deionized water and vacuum drying.

[0051] Specifically, Fe3O4NPs were added to a certain amount of oily wastewater, heated and stirred at a certain temperature and stirring speed, and then placed in a cooling box to cool to room temperature. Fe3O4NPs were then separated using a magnetic block to obtain treated wastewater samples and recovered Fe3O4NPs samples. The oil removal rate was calculated by gravimetric method, and a comparative experiment on the oil removal rate was conducted to evaluate the oil removal effect of Fe3O4NPs under different conditions.

[0052] The stability of Fe3O4NPs was characterized using a Zeta potentiometer; the morphology and size of Fe3O4NPs were characterized using scanning electron microscopy and transmission electron microscopy; the organic functional groups in Fe3O4NPs were characterized using Fourier transform infrared spectroscopy; the crystal structure of Fe3O4NPs was characterized using X-ray diffraction; and the magnetic hysteresis characteristics of Fe3O4NPs were characterized using a hysteresis loop analyzer.

[0053] Performance test results show that the material has an average particle size of 12.54 nm and is an irregular sphere; the XRD pattern shows pure cubic Fe3O4 with no impurity phase; the saturation magnetization is 52.21 emu / g; the Zeta potential is -32.5 mV; the oil removal rate is 92.66%; after recycling, it can be reused 5 times, and the oil removal rate is still ≥85%.

[0054] Example 2

[0055] The difference from Example 1 is that the amount of bamboo leaf extract injected in step 2 is 8 mL, while the other parameters remain unchanged.

[0056] Performance test results show that the material has an average particle size of 15.32 nm, a saturation magnetization of 50.17 emu / g, a zeta potential of -30.2 mV, an oil removal rate of 88.64%, and an oil removal rate of ≥82% after 5 reuses.

[0057] Example 3

[0058] The difference from Example 1 is that the molar ratio of FeCl·4H2O to FeCl3·6H2O is 1:1.8, while the other parameters remain unchanged.

[0059] Performance test results show that the material has an average particle size of 13.76 nm, a saturation magnetization of 49.83 emu / g, a zeta potential of -29.8 mV, an oil removal rate of 89.31%, and an oil removal rate of ≥83% after 5 repeated uses.

[0060] Example 4

[0061] The difference from Example 1 is that in step 2, the pH is adjusted to 10 using NH3·H2O, while the other parameters remain unchanged.

[0062] Performance test results show that the material has an average particle size of 14.25 nm, a saturation magnetization of 48.56 emu / g, a zeta potential of -28.7 mV, an oil removal rate of 87.92%, and an oil removal rate of ≥81% after 5 reuses.

[0063] Example 5

[0064] The difference from Example 1 is that the subsequent stirring temperature in step 2 is 65°C, while the other parameters remain unchanged.

[0065] Performance test results show that the material has an average particle size of 16.18 nm, a saturation magnetization of 47.92 emu / g, a zeta potential of -27.9 mV, an oil removal rate of 86.75%, and an oil removal rate of ≥80% after 5 reuses.

[0066] Comparative Example 1

[0067] The difference from Example 1 is that bamboo leaf extract is not added in step 2, and 0.3g of ascorbic acid (chemical reducing agent) is used instead, while the other parameters remain unchanged.

[0068] Performance test results show that the material has an average particle size of 23.67 nm and obvious agglomeration; XRD pattern shows a small amount of FeO impurity phase; saturation magnetization is 42.35 emu / g; Zeta potential is -22.1 mV; oil removal rate is 75.43%; after repeated use 5 times, the oil removal rate drops to below 60%, and the adsorption performance decays rapidly due to agglomeration.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that bamboo leaf extract is not added in step 2, while the other parameters remain unchanged.

[0071] Performance test results show that the material is severely agglomerated, with an average particle size >50nm; the XRD pattern shows a lot of impurities and the Fe3O4 crystal form is impure; the saturation magnetization is 38.72 emu / g; the Zeta potential is -18.5mV; the oil removal rate is only 68.29%; and the oil removal rate is <50% after being reused twice.

[0072] Comparative Example 3

[0073] The difference from Example 1 is that AMPS is not added in step 2, while the other parameters remain unchanged.

[0074] Performance test results show that the material has an average particle size of 18.94 nm and poor dispersibility; saturation magnetization of 51.03 emu / g; Zeta potential of -25.3 mV; oil removal rate of 82.17%; and oil removal rate of ≥75% after 5 repeated uses. The lack of AMPS leads to a decrease in the adhesion between the material and oil stains.

[0075] Comparative Example 4

[0076] The existing hydrothermal synthesis method was adopted: 0.5g FeCl2·4H2O and 1.35g FeCl3·6H2O were weighed, dissolved in 40mL deionized water, 5mL of 25% NH3·H2O was added, and after stirring for 30min, the mixture was transferred to a 50mL high-pressure reactor and reacted at 180℃ for 4h. After cooling, the mixture was magnetically separated, washed, and dried to obtain Fe3O4NPs. The oil removal application parameters were the same as in Example 1.

[0077] Performance test results show that the material has an average particle size of 20.45 nm, a saturation magnetization of 45.68 emu / g, and an oil removal rate of 78.36%. The preparation process requires a high-pressure reactor, which consumes a lot of energy. After being reused 5 times, the oil removal rate is ≥70%, but the preparation process is complex and not suitable for industrialization.

[0078] Comparative Example 5

[0079] The difference from Example 1 is that in step 1, ginkgo leaf extract is used instead of bamboo leaf extract, while the other parameters remain unchanged.

[0080] Performance test results show that the material has an average particle size of 17.83 nm, a saturation magnetization of 46.92 emu / g, a zeta potential of -26.5 mV, and an oil removal rate of 83.45%. After being reused 5 times, the oil removal rate is ≥78%. The content of effective functional groups in Ginkgo biloba extract is lower than that in bamboo leaf extract, resulting in poor adsorption performance and stability.

[0081] The results of Examples 1-5 show that when the parameters such as the amount of bamboo leaf extract, the Fe salt molar ratio, pH value, and reaction temperature are adjusted within a reasonable range in the preparation method described in this invention, stable Fe3O4NPs degreasing materials can be prepared with an oil removal rate of ≥86% and can be reused. Among them, Example 1 has the best performance, with an oil removal rate of 91.98% and the best dispersibility and stability.

[0082] The results of comparative examples 1-5 show that:

[0083] Bamboo leaf extract is key to ensuring the purity and good dispersibility of Fe3O4NPs crystals. In contrast, when bamboo leaf extract is not available in Comparative Examples 1 and 2 or when chemical reagents are used instead, the materials exhibit severe agglomeration, numerous impurities, and low oil removal rate.

[0084] The addition of AMPS can enhance the adhesion between the material and the oil stains and improve the oil removal efficiency. In Comparative Example 3, the oil removal rate decreased significantly when no AMPS was added.

[0085] Compared with the hydrothermal synthesis method (Comparative Example 4), the room temperature stirring synthesis method of the present invention has a simpler process, lower energy consumption, and better material properties.

[0086] Bamboo leaf extract is more effective than other plant extracts (Comparative Example 5). Its functional groups such as -COOH, -C=O, and -CHO can more efficiently stabilize Fe3O4NPs and adsorb oil stains.

[0087] Oil removal experiments showed that Fe3O4NPs exhibited strong oil removal capabilities under optimal conditions, namely, concentration, temperature, treatment time, and stirring speed of 400 mg / L, 40℃, 20 min, and 200 rpm, respectively, demonstrating the excellent oil removal performance of biosynthesized Fe3O4NPs.

[0088] like Figure 2 As shown, 2923cm -1 1660cm -1 1396cm -1 and 1028cm -1The peaks at the left and right are the asymmetric stretching vibration peak of -CH, the stretching vibration peak of C=O bond, the bending vibration peak of CH, and the stretching vibration peak of CO bond, respectively. However, some slight deviations were observed in the infrared absorption spectra of Fe3O4 NPs and bamboo leaf extract. These deviations may be due to the formation of coordination bonds between the carboxyl groups in the plant extract and the iron ions on the Fe3O4 surface, or the formation of hydrogen bonds between the C=O bonds and surrounding molecules or groups, thus affecting the vibrational frequency of the C=O bonds. Alternatively, organic components in the bamboo leaf extract (such as phenols, aldehydes, ketones, etc.) may interact with the surface of Fe3O4 nanoparticles to form coordination bonds or hydrogen bonds, leading to a shift in the vibrational peaks. The infrared absorption spectrum of Fe3O4 NPs shows that at 575 cm⁻¹... -1 A strong absorption peak appeared on the left and right sides, corresponding to the Fe-O characteristic vibration of Fe3O4, indicating the successful synthesis of Fe3O4NPs; the peak appeared at 3404 cm⁻¹. -1 The relatively broad and strong peaks on the left and right are the stretching vibration peaks of OH. In this range, Fe3O4NPs have lower transmittance than plant extracts, and more light is absorbed. This indicates that the bioactive substances in bamboo leaf extract participate in the synthesis of Fe3O4NPs as reducing agents and stabilizers.

[0089] like Figure 3 As shown, the lower the absolute value of the Zeta potential, the more the material tends to condense or aggregate. The dividing line of the dispersion stability of NPs in the aqueous phase is usually +30mV or -30mV. That is, if the Zeta potential of NPs in the aqueous phase is higher than +30mV or lower than -30mV, the dispersion system is relatively stable. The Zeta potential difference of Fe3O4NPs is -32.5mV, which shows very good stability.

[0090] like Figure 4 As shown, the SEM and TEM results show that most of the nanoparticles are between 8 and 20 nm in size, with irregular spherical shapes and basically uniform size.

[0091] like Figure 5 As shown, Fe3O4NPs exhibit distinct diffraction peaks at 30.2°, 35.6°, 43.2°, 53.7°, 57.2°, and 62.9°, corresponding to the (220), (311), (400), (422), (511), and (440) crystal planes of cubic Fe3O4 grains, respectively. This is consistent with the standard Fe3O4 spectrum, and the absence of diffraction peaks from other crystals indicates that the sample has a single crystal form and is a pure Fe3O4 particle.

[0092] like Figure 6As shown in the image, the maximum saturation magnetization is 52.21 emu / g. The hysteresis loop of Fe3O4NPs is a typical "S"-shaped curve with very low coercivity and almost no hysteresis, indicating that the particle sample has superparamagnetism. That is, Fe3O4NPs has high magnetism under the condition of an external magnetic field. However, its magnetic properties disappear quickly after the external magnetic field is removed, so there is no particle aggregation. This shows that the prepared Fe3O4NPs has excellent recycling value.

[0093] like Figure 7 As shown in the figure, the wastewater before and after treatment with Fe3O4NPs is compared. Figure a shows the wastewater before treatment with Fe3O4NPs, and Figure b shows the wastewater after treatment with Fe3O4NPs. It can be observed that the oil content of the treated wastewater is significantly reduced, which indicates that Fe3O4NPs has excellent oil removal performance.

[0094] This invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims.

Claims

1. A method for synthesizing Fe3O4 nano-oil-removing material from bamboo leaf extract, characterized in that, include: Step 1: Weigh 10g of bamboo leaf powder and place it in a 100mL vial. Add 90mL of deionized water and mix. Place the vial in a rotor and heat and stir at 80℃ and 660rpm for 30min. Cool to room temperature and centrifuge at 8000rpm for 20min. Take the supernatant and filter it through a 0.45μm filter membrane to obtain bamboo leaf extract. Step 2: Weigh 0.5g of analytical grade FeCl2·4H2O and 1.35g of analytical grade FeCl3·6H2O into a 50mL vial, with a molar ratio of FeCl2·4H2O to FeCl3·6H2O of 1:

2. Place the rotor in the vial, cap it, and insert a needle into the stopper. Heat and stir the vial at 80℃ and 660rpm for 30min. Then, inject 10mL of the bamboo leaf extract obtained in Step 1 into the vial using a syringe, and immediately add 1.5mL of analytical grade 2-acrylamide-2-methylpropanesulfonic acid (AMPS). Add 2mL of NH3·H2O to adjust the pH of the mixed solution to 11, and continue stirring at 80℃ and 660rpm for 1h. Step 3: After the mixed solution obtained in Step 2 is cooled to room temperature, the black precipitate is collected with a magnet, washed three times with deionized water, ultrasonically dispersed for 10 minutes, and then dried using a vacuum freeze dryer to obtain Fe3O4NPs powder.

2. The method for synthesizing Fe3O4 nano-oil-removing material from bamboo leaf extract according to claim 1, characterized in that, The bamboo leaf powder in step 1 is dried bamboo leaf powder that has been crushed and passed through a 100-mesh sieve.

3. The method for synthesizing Fe3O4 nano-oil-removing material from bamboo leaf extract according to claim 1, characterized in that, The 2 mL of NH3·H2O added in step 2 has a mass fraction of 25%~28%.

4. A Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract, characterized in that, The Fe3O4 nano-oil-removing material is prepared by the method described in any one of claims 1 to 3, comprising: Fe3O4NPs were synthesized using bamboo leaf extract as a reducing agent, stabilizer, and capping agent. The average particle size of the Fe3O4 nano-oil degreasing material is 8-20 nm, and the morphology is irregular spherical. In the X-ray diffraction pattern, diffraction peaks are observed at 30.2°, 35.6°, 43.2°, 53.7°, 57.2°, and 62.9°, which correspond to the (220), (311), (400), (422), (511), and (440) crystal planes of cubic Fe3O4, respectively. No other impurities are present. The Fe3O4 nano-oil degreasing material has superparamagnetism and a saturation magnetization of 52.21 emu / g.

5. The Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract according to claim 4, characterized in that, The absolute value of the Zeta potential of the Fe3O4NPs is not less than 30mV, preferably -32.5mV.

6. The Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract according to claim 4, characterized in that, The Fe3O4 nano-oil degreasing material is coated with organic functional groups from bamboo leaf extract, including -COOH, -C=O, and -CHO.

7. An application of a Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract, characterized in that, include: The Fe3O4NPs oil removal material was added to the oily wastewater, and the concentration of Fe3O4NPs was controlled at 400 mg / L. The mixture was heated and stirred at 40℃ and 200 rpm for 20 min. After the mixture was cooled to room temperature in a cooling box, Fe3O4NPs were separated by a magnet to obtain the treated wastewater.

8. The application of the Fe3O4 nano-oil-removing material synthesized from bamboo leaf extract according to claim 7, characterized in that, The oil content of the oily wastewater is 50~500mg / L; after treatment, the oil removal rate is ≥90%, and the separated Fe3O4NPs can be reused after washing with deionized water and vacuum drying.

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