A piezoelectric self-Fenton composite film, its preparation method and application

Abstract

The present invention discloses a piezoelectric self-Fenton composite film, a preparation method thereof and an application thereof, belonging to the technical field of organic pollutant treatment. The preparation method of the piezoelectric self-Fenton composite film of the present invention comprises the following steps: dissolving PVDF in an organic solvent to obtain a polymer solution; adding iron, MgO and rGO into the organic solvent for cell disruption treatment, and then adding the polymer solution and mixing evenly to obtain a mixed solution; spreading the mixed solution to obtain the piezoelectric self-Fenton composite film. The piezoelectric self-Fenton composite film prepared by the present invention has a high pollutant degradation rate, a high catalyst recovery efficiency and excellent loading characteristics; moreover, the preparation method of the piezoelectric self-Fenton composite film of the present invention is simple and easy to recycle, has excellent degradation effects on various dyes and mixed dyes, and can be widely applied to the routine treatment of organic pollutants in multiple scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of organic pollutant treatment, and particularly to a piezoelectric self-Fenton composite film, a preparation method thereof, and an application thereof. Background Art

[0002] Due to the growth of the world population and the rapid development of industry, the demand for environmental protection is increasing continuously. Water-soluble organic dye pollutants have high stability and are particularly difficult to treat, which can cause serious health and environmental problems. To solve this serious problem, there is an urgent need to develop environmentally friendly, convenient, and inexpensive technologies for degrading organic pollutants.

[0003] Currently, the Fenton process (one of the advanced oxidation processes (AOPs)) is generally used for the degradation and removal of organic dye pollutants. This process mainly uses Fe 2+ to catalyze H2O2 to generate ·OH with a higher redox potential to achieve catalytic oxidation, which has a good removal effect, but there are problems of high treatment cost and being limited by the environmental pH. Based on the above problems, researchers have found a piezoelectric material through research. Its microscopic structure has non-centrosymmetry, and under the action of mechanical force, the separation of electron-hole pairs can be realized, and further react with O2 and H2O in the environment to generate reactive oxygen species (ROS), including ·OH, ·O2 - , 1 O2, and H2O2, etc., achieving the effect of degrading organic dye pollutants. However, the piezoelectric catalytic activity of the currently developed piezoelectric materials is still far from satisfactory. Summary of the Invention

[0004] The purpose of the present invention is to provide a piezoelectric self-Fenton composite film, a preparation method thereof, and an application thereof to solve the problems existing in the above-mentioned prior art. The present invention blends the heterogeneous Fenton material Fe3O4 with MgO and rGO as fillers and uniformly disperses them in the piezoelectric material PVDF to prepare a composite film, achieving the effective degradation of organic pollutants and the efficient recovery of the catalyst.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: A preparation method of a piezoelectric self-Fenton composite film, comprising the following steps:

[0007] Dissolve PVDF in an organic solvent to obtain a polymer solution;

[0008] Add MgO and rGO to an organic solvent for cell disruption treatment, and then add the polymer solution and mix evenly to obtain a mixed solution;

[0009] After spreading the mixed solution flat, deionized water is sprayed on the surface to obtain the piezoelectric self-Fenton composite film.

[0010] Further, the method for preparing the piezoelectric self-Fenton composite film further includes adding iron while adding MgO and rGO.

[0011] Further, the iron includes Fe, Fe2O3, Fe3O4, FeS2, FePO4, FeC2O4 or FePc.

[0012] Further, the PVDF includes PVDF-HFP; the dosages of the iron, MgO and rGO are all 3% of the mass of the piezoelectric self-Fenton composite film.

[0013] Further, the cell crushing treatment is ultrasonic crushing treatment; the power of the ultrasonic crushing treatment is 97.5 W, the total time is 25 min, and the ultrasonic mode is on for 1.5 s and off for 2 s.

[0014] The second technical solution of the present invention: A piezoelectric self-Fenton composite film prepared by the above preparation method.

[0015] The third technical solution of the present invention: An application of the above piezoelectric self-Fenton composite film in degrading organic pollutants.

[0016] Further, the organic pollutants include one or more of rhodamine B (RhB), methylene blue (MB) and methyl orange (MO).

[0017] The fourth technical solution of the present invention: A method for degrading organic pollutants by piezoelectric self-Fenton, including the following steps: soaking the above piezoelectric self-Fenton composite film in a solution of organic pollutants, and performing piezoelectric self-Fenton degradation reaction under ultrasonic action after dark adsorption.

[0018] Mechanism of degrading organic pollutants by piezoelectric self-Fenton:

[0019] Abundant mechanical energy in the environment acts on the piezoelectric material, causing it to deform. The dipole moment generated by the non-centrosymmetric structure in the microscopic structure of the material will be macroscopically manifested as a piezoelectric field. The piezoelectric field acts as a driving force to promote the generation of ROS, and the Fenton material can further catalyze H2O2 to generate more high-energy free radicals. In this process, rGO serves as a high-speed transmission channel for separating carriers, promoting the effective separation of electron-hole pairs. MgO provides more abundant active sites for the composite film to improve the degradation efficiency of organic pollutants.

[0020] The present invention discloses the following technical effects:

[0021] (1) The piezoelectric self-Fenton composite film prepared by the present invention has a high pollutant degradation rate: for various pollutants, the degradation rate of this material can reach 50-90% or more within 30 minutes;

[0022] It has a high catalyst recovery efficiency: the recovery of this material is simple and convenient, effectively reducing the degradation cost;

[0023] It has excellent loading characteristics: this material can be loaded on the surfaces of objects with various complex shapes to realize the utilization of mechanical energy in various environments;

[0024] It has wide applications: this material is simple to prepare and easy to recycle, and has excellent degradation effects on various dyes and mixed dyes, and can be widely used in the routine treatment of organic pollutants in multiple scenarios.

[0025] (2) The piezoelectric self-Fenton composite film of the present invention can effectively improve the piezoelectric catalytic activity, avoiding the use limitations of the traditional Fenton process (high treatment cost, limited by environmental pH), and providing a new technical means for the routine treatment of organic pollutants. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 shows the degradation effects of different piezoelectric self-Fenton composite films on Rhodamine B;

[0028] Figure 2 shows the degradation effects of different piezoelectric self-Fenton composite films on Methylene Blue;

[0029] Figure 3 shows the degradation effects of different piezoelectric self-Fenton composite films on Methyl Orange;

[0030] Figure 4 shows the ultraviolet curve heat map of the degradation of mixed dyes by different piezoelectric self-Fenton composite films;

[0031] Figure 5 shows the decolorization effects of different piezoelectric self-Fenton composite films on the degradation of mixed dyes at 60 minutes;

[0032] Figure 6 shows the degradation effects of different films on Rhodamine B;

[0033] Figure 7Degradation effect of the piezoelectric self-Fenton composite film on Rhodamine B under different pH degradation environments;

[0034] Figure 8 Comparison of the 30-min degradation effect of the piezoelectric self-Fenton composite film on Rhodamine B under different pH degradation environments. Detailed implementation manners

[0035] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation embodiments of the present invention.

[0036] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0037] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0038] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the specification of the present invention, which are obvious to those skilled in the art. Other implementation manners obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are only exemplary.

[0039] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0040] PVDF-HFP was purchased from Sigma-Aldrich, product number: 427187, and its density at 25 °C is 1.78 g / mL.

[0041] Example 1

[0042] A preparation method of a MgO@rGO@Fe3O4 / PVDF-HFP piezoelectric self-Fenton composite film:

[0043] (1) Dissolve 0.5 g of PVDF-HFP particles in 5 ml of organic solvent (DMAC) to obtain a polymer solution.

[0044] (2) Take Fe3O4, MgO and rGO (the dosages of Fe3O4, MgO and rGO are all 3% of the mass of the piezoelectric self-Fenton composite film) and add them to 3 ml of DMAC. Use cell disruption treatment for 25 min (the cell disruption treatment is ultrasonic disruption treatment; the power of the ultrasonic disruption treatment is 97.5 W, the total time is 25 min, and the ultrasonic mode is on for 1.5 s and off for 2 s), and then add them to the polymer solution prepared in step (1) and mix evenly to obtain a mixed solution.

[0045] (3) Spread the mixed solution evenly in a 60 mm petri dish and spray deionized water on the surface to obtain the MgO@rGO@Fe3O4 / PVDF-HFP piezoelectric self-Fenton composite film (denoted as 3% MgO@rGO@X / PVDF-HFP).

[0046] Example 2

[0047] Same as Example 1, the only difference is that Fe3O4 is replaced with an equal mass of Fe.

[0048] Example 3

[0049] Same as Example 1, the only difference is that Fe3O4 is replaced with an equal mass of Fe2O3.

[0050] Example 4

[0051] Same as Example 1, the only difference is that Fe3O4 is replaced with an equal mass of FeS2.

[0052] Example 5

[0053] Same as Example 1, the only difference is that Fe3O4 is replaced with an equal mass of FePO4.

[0054] Example 6

[0055] Same as Example 1, the only difference is that Fe3O4 is replaced with an equal mass of FeC2O4.

[0056] Example 7

[0057] Same as Example 1, the only difference is that Fe3O4 is replaced with an equal mass of FePc.

[0058] Example 8 (Blank)

[0059] Same as Example 1, the only difference is that Fe3O4 is not added in step (2), and the obtained film is MgO@rGO / PVDF-HFP.

[0060] Comparative Example 1

[0061] Same as Example 1, except that rGO was not added in step (2), and the obtained film was MgO@Fe3O4 / PVDF-HFP.

[0062] Comparative Example 2

[0063] Same as Example 1, except that MgO was not added in step (2), and the obtained film was rGO@Fe3O4 / PVDF-HFP.

[0064] Comparative Example 3

[0065] Preparation method of PVDF-HFP:

[0066] (1) 0.5 g of PVDF-HFP particles were added to 8 ml of an organic solvent (DMAC) and dissolved to obtain a polymer solution.

[0067] (2) The polymer solution was spread evenly on a 60-mm petri dish, and deionized water was sprayed on the surface to obtain a PVDF-HFP film (denoted as PVDF-HFP).

[0068] Effect Example 1

[0069] (1) Prepare a 1×10 -5 mol / L rhodamine B solution (simulating rhodamine B wastewater, prepared using deionized water), a 1×10 -5 mol / L methylene blue solution (simulating methylene blue wastewater, prepared using deionized water), or a 1×10 - 5 mol / L methyl orange solution (simulating methyl orange wastewater, prepared using deionized water). 10 ml of each was taken and placed in a beaker as the solution to be degraded. 50 mg of the piezoelectric self-Fenton composite films prepared in Examples 1 to 8 were respectively placed in the rhodamine B, methylene blue, or methyl orange solution. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, a piezoelectric self-Fenton degradation experiment was carried out. The degradation time was 30 min. During the degradation process, 4 ml of the degradation solution was taken every 5 min, and the absorbance of the degradation solution sample was measured on a UV-visible spectrophotometer (UV-2600). After the measurement, the degradation solution sample was poured back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation). The results are shown in Figures 1 to 3 , Figure 1 shows the degradation effects of different piezoelectric self-Fenton composite films on rhodamine B, Figure 2 shows the degradation effects of different piezoelectric self-Fenton composite films on methylene blue, Figure 3 shows the degradation effects of different piezoelectric self-Fenton composite films on methyl orange.

[0070] From Figures 1 to 3 It can be seen that the piezoelectric self-Fenton composite film prepared in the embodiment of the present invention exhibits good degradation efficiency for various organic pollutants.

[0071] Effect Example 2

[0072] (1) Prepare a mixed solution of rhodamine B, methylene blue and methyl orange (using deionized water for preparation). The concentration of each dye in the mixed dye is 1×10 -5 mol / L, and the total concentration is 3×10 -5 mol / L. Take 50 ml and place it in a beaker as the solution to be degraded.

[0073] Respectively place 100 mg of the film prepared in Example 8 (1-1, Blank), the film prepared in Example 2 (1-2, containing Fe), the film prepared in Example 4 (1-3, containing FeS2), and the film prepared in Example 1 (1-4, containing Fe3O4) into the mixed solution. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, carry out the piezoelectric self-Fenton degradation experiment. The degradation time is 60 min. During the degradation process, take 4 ml of the degradation solution every 5 min and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation).

[0074] Place 50 mg of the film prepared in Example 2 and 50 mg of the film prepared in Example 4 (the two films form 2-1) into the mixed solution. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, carry out the piezoelectric self-Fenton degradation experiment. The degradation time is 60 min. During the degradation process, take 4 ml of the degradation solution every 5 min and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation).

[0075] Place 50 mg of the film prepared in Example 2 and 50 mg of the film prepared in Example 1 (the two films form 2-2) into the mixed solution. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, carry out the piezoelectric self-Fenton degradation experiment. The degradation time is 60 min. During the degradation process, take 4 ml of the degradation solution every 5 min and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation).

[0076] Place 50 mg of the thin film prepared in Example 4 and 50 mg of the thin film prepared in Example 1 (the two films form Composition 2-3) in the mixed solution. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, carry out the piezoelectric self-Fenton degradation experiment. The degradation time is 60 min. During the degradation process, take 4 ml of the degradation solution every 5 min, and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation).

[0077] Place 25 mg of the thin film prepared in Example 8, 25 mg of the thin film prepared in Example 2, 25 mg of the thin film prepared in Example 4, and 25 mg of the thin film prepared in Example 1 (the four films form Composition 4-1) in the mixed solution. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, carry out the piezoelectric self-Fenton degradation experiment. The degradation time is 60 min. During the degradation process, take 4 ml of the degradation solution every 5 min, and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation).

[0078] Table 1 Grouping and dosage of thin films

[0079]

[0080] The measurement results are shown in Figure 4 and Figure 5 .

[0081] From Figure 4 and Figure 5 it can be seen that the MgO@rGO@Fe3O4 / PVDF-HFP piezoelectric self-Fenton composite thin film prepared in Example 1 has good degradation effects on the components in the mixed dye. It shows that the composite thin film doped with Fe3O4 as the iron source exhibits good redox activity in various single-dye and mixed-dye environments.

[0082] Effect Example 3

[0083] Prepare 1×10 -5A rhodamine B solution of Figure 6 mol / L (simulating rhodamine B wastewater, prepared with deionized water). Take 10 mL and place it in a beaker as the solution to be degraded. Respectively place 50 mg of the thin films prepared in Example 1, Example 8, and Comparative Examples 1 - 3 into the rhodamine B solution. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, conduct a piezoelectric self-Fenton degradation experiment for 30 min. During the degradation process, take 4 mL of the degradation solution every 10 min and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation). The results are shown in

[0084] Prepare a 1×10 -5 mol / L rhodamine B solution (simulating rhodamine B wastewater, prepared with deionized water). Take 10 mL and place it in a beaker as the solution to be degraded. Conduct a piezoelectric self-Fenton degradation experiment (denoted as US) on the solution to be degraded under the condition of an ultrasonic power of 240 W for 30 min. During the degradation process, take 4 mL of the degradation solution every 10 min and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation). The results are shown in Figure 6 。

[0085] Effect Example 4

[0086] Prepare a 1×10 -5 mol / L rhodamine B solution (simulating rhodamine B wastewater, prepared with deionized water), with an initial solution pH of 7. Take 10 mL and place it in a beaker as the solution to be degraded. Use HCl and NaOH to adjust the pH of the solution to be degraded to 3 and 11 respectively to obtain degradation solutions with different pH values. Respectively place 50 mg of the piezoelectric self-Fenton composite thin films prepared in Example 1 and Example 8 into the above degradation solutions with different pH values. After dark adsorption for 2 h, under the condition of an ultrasonic power of 240 W, conduct a piezoelectric self-Fenton degradation experiment for 30 min. During the degradation process, take 4 mL of the degradation solution every 10 min and measure the absorbance of the degradation solution sample on a UV-visible spectrophotometer (UV-2600). After the measurement, pour the degradation solution sample back into the beaker. Calculate the ratio of the absorbance at each time point of each group to the original absorbance (before degradation). The results are shown in Figure 7 。Comparison of the 30-min degradation rates of each group of samples is shown in Figure 8 。

[0087] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the spirit of the present invention's design, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a piezoelectric self-Fenton composite film for degrading rhodamine B, methylene blue and methyl orange, characterized in that: The following steps are involved: Add PVDF into an organic solvent and dissolve it to obtain a polymer solution; MgO, rGO and Fe3O4 are added into an organic solvent for cell crushing, and then the polymer solution is added and mixed evenly to obtain a mixed solution; The piezoelectric self-Fenton composite film is obtained by spreading the mixed solution.

2. The preparation method according to claim 1, characterized in that: The PVDF includes PVDF-HFP; The amount of Fe3O4, MgO and rGO used is 3% of the mass of the piezoelectric self-Fenton composite film.

3. The preparation method according to claim 1, characterized in that: The cell pulverization treatment is ultrasonic pulverization treatment; the power of the ultrasonic pulverization treatment is 97.5W, the total time is 25 minutes, and the ultrasonic mode is on for 1.5 seconds and off for 2 seconds.

4. A piezoelectric self-Fenton composite film prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the piezoelectric self-Fenton composite film according to claim 4 in degrading organic pollutants; The organic pollutants are rhodamine B, methylene blue and methyl orange.

6. A method for degrading organic pollutants by piezoelectric self-Fenton, characterized in that: The method comprises the following steps: immersing the piezoelectric self-Fenton composite film according to claim 4 in a solution of organic pollutants, performing a piezoelectric self-Fenton degradation reaction under the action of ultrasound after dark adsorption; The organic pollutants are rhodamine B, methylene blue and methyl orange.

Images