A method for degrading various perfluorinated and polyfluorinated compounds in water using polytetrafluoroethylene powder piezoelectric catalysis

Abstract

The present invention belongs to the technical field of degradation of perfluorinated and polyfluorinated compounds, and specifically relates to a method for piezoelectrically catalytically degrading a variety of perfluorinated and polyfluorinated compounds in water using polytetrafluoroethylene powder. The present invention uses polytetrafluoroethylene as a piezoelectric catalyst and, through ultrasonic vibration, piezoelectrically degrades a variety of perfluorinated and polyfluorinated compounds in water. The present invention is green and pollution-free, has strong operability, and a wide range of applications. The piezoelectric degradation of perfluorinated and polyfluorinated compounds using polytetrafluoroethylene has good degradation efficiency and excellent stability, and does not produce secondary pollution. The present invention uses a simple piezoelectric catalytic technology to use polytetrafluoroethylene powder as a catalyst to achieve efficient degradation of a variety of perfluorinated and polyfluorinated compounds in water.

Description

Technical Field

[0001] The invention belongs to the technical field of degradation of perfluorinated and polyfluorinated compounds, and particularly relates to a method for degrading various perfluorinated and polyfluorinated compounds in water by utilizing polytetrafluoroethylene powder for piezoelectric catalysis. Background Art

[0002] Per- and polyfluoroalkyl substances (PFASs) are aliphatic substances containing one or more perfluorinated carbons. Due to their increased surface activity, enhanced stability, and hydrophobic and oleophobic properties, PFASs are widely used in industrial, agricultural, and commercial applications, including firefighting foams, personal care products, food contact materials, medical devices, pesticides, textiles, electroplating, leather, and clothing. Furthermore, PFASs contain a large number of C—F bonds, with a bond energy of 485.3 kJ / mol, making them one of the most stable chemical bonds and difficult to degrade even under extreme conditions. Their high thermal and chemical stability make them resistant to natural hydrolysis, photolysis, and biodegradation in the environment, resulting in their persistence and long-term presence. Due to their unique persistence and bioaccumulation, PFASs have been detected in water worldwide, even in polar regions. Worryingly, toxicological and epidemiological studies have shown that non-polymeric PFASs can bind to proteins and subsequently accumulate in the body, leading to liver toxicity, kidney cancer, and disruptions of lipid metabolism, the immune system, and the endocrine system, posing a serious threat to the ecological environment and human health. In addition, due to differences in structure and functional groups, the difficulty of degrading various PFASs is also different. Therefore, it is urgent to eliminate various PFASs in water.

[0003] In the development of new energy technologies, piezocatalysis, as an emerging technology that uses the piezoelectric effect to remove difficult-to-degrade pollutants, has received widespread attention. When piezoelectric materials are subjected to external mechanical stress, a built-in electric field is formed, achieving efficient charge separation within the piezocatalyst. Piezocatalysis can utilize environmentally friendly natural energy such as wind, water, and tidal energy for conversion, and has become an emerging and attractive research field in recent years. Currently, there is relatively little research on the effective degradation of persistent perfluorinated and polyfluorinated compound pollutants through piezocatalysis, and the scope of application is limited.

[0004] It is reported that the piezoelectric coefficient d of polytetrafluoroethylene electret 33Reaching ~600 pC / N, it is higher than traditional piezoelectric materials and has excellent piezoelectric catalytic potential. Furthermore, toxicological studies have demonstrated that PTFE, due to its high molecular weight, cannot cross cell membranes and is not bioavailable or bioaccumulative. At the same time, PTFE retains the high stability provided by C-F bonds, enabling it to maintain good performance even under harsh conditions. Therefore, PTFE is expected to become an ideal piezoelectric catalytic material for the degradation of per- and polyfluorinated compounds. Summary of the Invention

[0005] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a method for piezoelectrically catalytically degrading a variety of perfluorinated and polyfluorinated compounds in water using polytetrafluoroethylene powder, which uses polytetrafluoroethylene powder as a catalyst to achieve efficient degradation of a variety of perfluorinated and polyfluorinated compounds in water.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] The present invention provides a method for degrading various perfluorinated and polyfluorinated compounds in water by using polytetrafluoroethylene powder for piezoelectric catalysis. Specifically, polytetrafluoroethylene is used as a piezoelectric catalyst, polytetrafluoroethylene is added into water containing perfluorinated and polyfluorinated compounds, and the perfluorinated and polyfluorinated compounds in the water are degraded after the action of ultrasonic vibration.

[0008] Preferably, the perfluoro and polyfluoro compounds include perfluorooctanoic acid, perfluorononanoic acid, perfluorooctanesulfonic acid, and hexafluoropropylene oxide dimer acid.

[0009] Preferably, the ratio of the mass of the polytetrafluoroethylene to the volume of water is (10-30) mg / 60 mL.

[0010] Preferably, the concentration of the perfluorinated and polyfluorinated compounds in water is 2-10 mg / L.

[0011] Preferably, the power of ultrasonic vibration is 2-3W / cm 2 .

[0012] Preferably, the ultrasonic vibration is applied for no less than 1 hour.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention discloses a method for piezoelectrically catalytically degrading various perfluorinated and polyfluorinated compounds in water using polytetrafluoroethylene powder. Polytetrafluoroethylene is used as a piezoelectric catalyst, and ultrasonic vibration is used to piezoelectrically degrade the various perfluorinated and polyfluorinated compounds in water. The present invention is green and pollution-free, highly operable, and has a wide range of applications. Furthermore, the piezoelectric degradation of perfluorinated and polyfluorinated compounds using polytetrafluoroethylene has good degradation efficiency and excellent stability, and does not produce secondary pollution. Thus, the present invention achieves efficient degradation of various perfluorinated and polyfluorinated compounds in water using polytetrafluoroethylene powder as a catalyst through a simple piezoelectric catalytic technology, and has great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Flowchart for the piezoelectric catalytic degradation of various per- and polyfluorinated compounds in water using polytetrafluoroethylene powder;

[0016] Figure 2 Performance diagram of degradation of different per- and polyfluorinated compounds in water using polytetrafluoroethylene powder;

[0017] Figure 3 This is the XRD comparison diagram of polytetrafluoroethylene powder before and after piezoelectric catalysis;

[0018] Figure 4 Effects of different sacrificial agents on the piezoelectric degradation of per- and polyfluorinated compounds over polytetrafluoroethylene. DETAILED DESCRIPTION

[0019] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0020] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0021] Example 1 A method for degrading various perfluorinated and polyfluorinated compounds in water using polytetrafluoroethylene powder piezoelectric catalysis

[0022] according to Figure 1 The roadmap shown includes the following steps:

[0023] (1) Place an aqueous solution containing perfluorooctanoic acid in a quartz bottle, and the concentration of the solution is 5 mg / L.

[0024] (2) Weigh 10 mg of polytetrafluoroethylene powder (McLean, CAS: 9002-84-0) and disperse it in the solution of step (1).

[0025] (3) Place the quartz bottle containing the polytetrafluoroethylene powder solution dispersed in step (2) in an ultrasonic water tank, and then 2 Ultrasonic vibration is performed at a power of .

[0026] (4) Piezoelectric catalytic degradation of perfluorooctanoic acid for 1 hour, taking samples every 25 minutes, measuring their concentrations by high performance liquid chromatography, and calculating their degradation efficiency. The degradation efficiency is calculated according to the following formula:

[0027] R = (1-C / C0) × 100%;

[0028] R: degradation efficiency;

[0029] C0: initial degradation concentration;

[0030] C: concentration after degradation reaction.

[0031] At the same time, the same method was used to investigate the piezoelectric catalytic degradation effect of polytetrafluoroethylene on perfluorononanoic acid, perfluorooctanesulfonic acid, and hexafluoropropylene oxide dimer acid. The test and calculation results are as follows Figure 2 and Figure 3 shown.

[0032] Depend on Figure 2 It can be seen that polytetrafluoroethylene powder has a good degradation effect on perfluorooctanoic acid, perfluorononanoic acid, perfluorooctane sulfonic acid and hexafluoropropylene oxide dimer acid in water.

[0033] Depend on Figure 3 It can be seen that the XRD patterns of polytetrafluoroethylene powder remain unchanged before and after piezoelectric catalytic degradation, indicating good stability.

[0034] Example 2 Mechanism of Piezoelectric Catalytic Degradation of Perfluorinated and Polyfluorinated Compounds by Polytetrafluoroethylene

[0035] During the degradation of perfluorooctanoic acid using the method of Example 1, different sacrificial agents were added to the perfluorooctanoic acid solution at a concentration of 10 mmol / L. The sacrificial agents used included sodium ethylenediaminetetraacetate (EDTA-Na) for capturing holes generated by piezoelectricity, potassium dichromate for capturing electrons generated by piezoelectricity, L-ascorbic acid for capturing peroxyl radicals (O2-), and mannitol for capturing hydroxyl radicals (OH). According to the test and calculation results, Figure 4 .

[0036] Depend on Figure 4It can be seen that potassium dichromate, L-ascorbic acid and mannitol showed negligible effects on the degradation efficiency of PFOA. In contrast, when EDTA-Na was used as a sacrificial agent, the degradation rate dropped from 93.4% to 27.9%, indicating that the piezoelectrically generated holes played a vital role in the piezoelectric catalytic degradation process, indicating that polytetrafluoroethylene degraded PFOA through the hole oxidation pathway, causing PFOA to gradually decompose into final products.

[0037] In summary, the present invention achieves efficient degradation of various perfluorinated and polyfluorinated compounds in water by using a simple piezoelectric catalytic technology and polytetrafluoroethylene powder as a catalyst, and has great application prospects.

[0038] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A method for degrading various perfluorinated and polyfluorinated compounds in water by piezoelectric catalysis using polytetrafluoroethylene powder, characterized in that: Polytetrafluoroethylene is used as a piezoelectric catalyst, and the polytetrafluoroethylene is added to water containing perfluorinated and polyfluorinated compounds. The perfluorinated and polyfluorinated compounds in the water are degraded by ultrasonic vibration. The ratio of the mass of the polytetrafluoroethylene to the volume of water is (10-30) mg / 60 mL, the concentration of the perfluorinated and polyfluorinated compounds in the water is 2-10 mg / L, and the power of the ultrasonic vibration is 2-3 W / cm 2 ; The perfluoro and polyfluoro compounds include perfluorooctanoic acid, perfluorononanoic acid, perfluorooctane sulfonic acid, or hexafluoropropylene oxide dimer acid.

2. The method for degrading various perfluorinated and polyfluorinated compounds in water by piezoelectric catalysis using polytetrafluoroethylene powder according to claim 1, characterized in that: The ultrasonic vibration action time is not less than 1 hour.

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