Degradation method of perfluorinated compound
By generating water radical cation clusters through a multi-needle array device, the problem of difficult degradation of perfluorinated compounds was solved, efficient and low-cost degradation of perfluorinated compounds was achieved, and innovation in environmental governance was promoted.
Patent Information
- Application Number
- CN202510543136.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-28
- Publication Date
- 2025-09-05
AI Technical Summary
Existing technologies make it difficult to efficiently degrade perfluorinated compounds. Conventional methods are costly and require harsh conditions, which limits their application in the environment.
A multi-needle array device is used to generate highly active water radical cations and their clusters through corona discharge, which react with perfluorinated compounds to achieve degradation, avoiding the need for extreme conditions.
The efficient degradation of perfluorinated compounds can be achieved at room temperature and pressure, which simplifies the operational complexity and cost, has the advantages of being green and environmentally friendly, and meets the needs of sustainable development.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of environmental pollution control, in particular to a method for degrading perfluorinated compounds. Background Art
[0002] Perfluorinated compounds (PFCs) are a large class of synthetic organic chemicals characterized by the partial or complete replacement of hydrogen atoms on their carbon skeletons with fluorine atoms. Their stable C-F bonds give them unique physicochemical properties, such as high thermal and chemical stability, and hydrophobicity and oleophobicity. These unique properties have led to their widespread application across various industries. However, the large-scale production and use of PFCs, as well as their persistence and bioaccumulation in the environment, pose a serious threat to human health and ecosystems. Studies have clearly linked PFCs to a variety of health issues, including, but not limited to, increased cancer risk, kidney damage, reproductive system abnormalities, immune system suppression, and endocrine disruption. Currently, the two most common long-chain PFCs, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), were added to the Stockholm Convention on Persistent Organic Pollutants (POPs) control list in 2009 and 2019, respectively. Countries are required to take measures to restrict their production, use, and emissions. Therefore, the hazards posed by PFCs to human health and ecosystems warrant further attention.
[0003] Due to the high energy of the C-H bond, conventional water treatment technologies struggle to completely degrade perfluorinated compounds. Emerging chemical degradation technologies, such as electrochemical oxidation, photocatalysis, and low-temperature plasma, have demonstrated promising results in degrading perfluorinated compounds. However, these approaches face challenges in expanding field applications due to the high cost of catalysts and demanding reaction conditions. Water radical cations, as a specialized form of water, play a vital role in various scientific and industrial fields due to their uniquely high reactivity and ability to promote complex chemical transformations. Studies have shown that the standard redox potential of water radical cations in aqueous solution exceeds 3 V, far exceeding that of many common redox reactions. Given these unique properties of water radical cations, exploring their potential for application in perfluorinated compound degradation not only promises to overcome the limitations of existing technologies but also offers novel solutions for the environmentally friendly treatment of perfluorinated compounds. Therefore, in-depth research and development of degradation technologies based on water radical cations is crucial for advancing innovation in perfluorinated compound pollution control. Summary of the Invention
[0004] The present invention aims to provide a perfluorinated compound degradation technology based on water radical cations. This method first places a perfluorinated compound solution of a certain concentration and volume on the negative plate below a multi-needle array device. By precisely controlling the discharge voltage and the distance between the needle tips and the negative plate, the water vapor surrounding the needle tips is ionized, generating short-lived but highly reactive water radical cations and their clusters. These highly reactive radical cations and their clusters can quickly and effectively collide and react with perfluorinated compound molecules, achieving efficient degradation.
[0005] The technical solutions of the present invention are as follows:
[0006] A method for degrading perfluorinated compounds comprises placing a perfluorinated compound solution of a certain concentration and volume in a discharge reaction device, and regulating the discharge so that water vapor is ionized through electron loss to form short-lived water radical cations and clusters thereof. The water radical cations can effectively react with the target pollutant perfluorinated compound molecules, thereby achieving their degradation.
[0007] Preferably, the perfluorinated compound is perfluorooctanoic acid and / or perfluorooctane sulfonic acid.
[0008] Preferably, the discharge reaction device comprises a high-voltage power supply device, a corona discharge array needle device and a negative electrode plate, wherein the corona discharge array needle device is connected to the positive electrode of the high-voltage power supply device, and the negative electrode plate is connected to the negative electrode of the high-voltage power supply device.
[0009] Preferably, the corona discharge array device includes an array plate and corona discharge needles located below the array plate.
[0010] Preferably, the negative electrode plate is made of stainless steel.
[0011] Preferably, the concentration of the perfluorinated compound solution is 10 to 200 mg / L.
[0012] Preferably, the volume of the perfluorinated compound solution is 5-7 mL.
[0013] Preferably, the discharge voltage is optimized between 4.0 and 7.0 kV.
[0014] Preferably, the distance between the tip of the corona discharge needle and the negative electrode plate is optimized to be between 3 and 9 mm.
[0015] The beneficial effects of the present invention are as follows: the present invention can realize the preparation of highly active water radical cations and their clusters only under normal temperature and pressure conditions through corona discharge ionization technology. This groundbreaking preparation method avoids the need for extreme conditions and greatly simplifies the complexity and cost of experiments or industrial applications. The prepared highly active water radical cation clusters show strong activity in chemical reactions and react with perfluorinated compounds to trigger a series of defluorination and chain scission, ultimately achieving deep degradation of perfluorinated compounds. This method has the advantages of simple operation, high efficiency and low consumption, and green environmental protection. It meets the current global urgent demand for sustainable development and environmental protection, and has brought major innovations and technological breakthroughs to the field of environmental governance. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:
[0017] Figure 1 Schematic diagram of the structure of the perfluorinated compound degradation device of the present invention; 1-high voltage power supply device, 2-corona discharge array device, 3-negative plate, 4-positive electrode, 5-negative electrode, 6-tungsten needle, 7-discharge distance, 8-sample solution;
[0018] Figure 2 The ion chromatograms and mass spectra of perfluorooctanoic acid before and after degradation are shown in Figure 1, where a is the ion chromatogram at different reaction times, b is the ionization mass spectrometry analysis before and after degradation, c is the m / z 411 tandem mass spectrometry analysis, and d is the m / z 409 tandem mass spectrometry analysis.
[0019] Figure 3 Mass spectra before and after the addition of perfluorooctanoic acid sulfonic acid. DETAILED DESCRIPTION
[0020] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.
[0021] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.
[0022] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.
[0023] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.
[0024] This paper designs a novel multi-needle array degradation device that uses corona discharge to ionize water vapor to generate highly active water radical cations and their clusters, which react with perfluorinated compounds to degrade them. The degradation effect and mechanism of water radical cations on perfluorinated compounds were investigated using perfluorooctanoic acid and perfluorooctane sulfonic acid as the research targets.
[0025] See also Figure 1-Figure 3 The degradation device used in the perfluorinated compound degradation method proposed by the present invention ( Figure 1 ), specifically including a high-voltage power supply device 1, a corona discharge array device 2 and a negative plate 3.
[0026] The corona discharge array device 2 consists of a group of 77 tungsten needles 6 evenly distributed in a 3.5×5.5 cm 2 The needle tip is sharp. When high voltage is applied, the moist water vapor near the needle tip will be ionized to form short-lived water radical cations and their clusters.
[0027] The negative electrode plate 3 is made of stainless steel, can hold 6 mL of sample solution 8 , and is connected to the negative electrode 5 of the high-voltage power supply device 1 .
[0028] There is a certain discharge distance 7 between the tip of the tungsten needle 6 and the negative plate 3 , and the discharge distance is optimized to be between 3 and 9 mm.
[0029] Based on the above device, the specific degradation methods of perfluorinated compounds include:
[0030] A 6 mL volume of perfluorinated compound solution was placed in the negative electrode plate 3, and the corona discharge array device and the negative electrode plate were connected to the positive and negative electrodes of the high-voltage power supply device, respectively. By adjusting the discharge voltage and the discharge distance of the high-voltage power supply device, the tip of the tungsten needle 6 was discharged, and the surrounding water vapor was ionized to form water radical cation clusters. The formed water radical cation clusters further reacted with the perfluorinated compound. The perfluorinated compound aqueous solution after the reaction was collected for ion chromatography and mass spectrometry analysis to evaluate the degradation effect.
[0031] The concentrations of PFOA and PFOS before and after degradation were quantified by mass spectrometry. A series of PFOA and PFOS standard solutions with concentrations of 0.01, 0.05, 0.1, 1, 2.5, 5, 10, and 20 mg / L were prepared and analyzed by electrospray ionization mass spectrometry in negative ion mode. m / z 413 and m / z 499 were used as characteristic ions of PFOA and PFOS, respectively, for quantitative analysis. A standard curve was drawn with the mass concentration of the solution as the horizontal axis and the characteristic ion signal intensity as the vertical axis. The regression equations obtained were y=54256.94x-7065.77 and y=67628.25.94x-14463.59, respectively. The linear correlation coefficient (R 2 ) were 0.9975 and 0.9960, respectively. The target ion signal intensity was detected by mass spectrometry, and the corresponding concentration was calculated based on the standard curve. The degradation rate was calculated based on the change in target compound concentration before and after the reaction. The degradation rate was calculated as follows: Degradation rate = (initial concentration - post-reaction concentration) / initial concentration × 100%.
[0032] In specific applications, it was found that the degradation performance of corona discharge is affected by the electric field strength and the sample itself. Based on this, the effects of different discharge distances (3, 6, and 9 mm), discharge voltages (4.0, 5.0, 6.0, and 7.0 kV), and initial solution concentrations (10, 50, 100, and 200 mg / L) on the degradation of perfluorooctanoic acid were studied. Through exploration and optimization of reaction conditions, the optimal reaction conditions were found to be a discharge distance of 3 mm, a discharge voltage of 7 kV, and an initial concentration of 10 mg / L.
[0033] The effectiveness of the above-mentioned perfluorinated compound degradation method is verified by several examples below:
[0034] Example 1
[0035] use Figure 1 In the degradation device, 6 mL of perfluorooctanoic acid solution was placed in the negative electrode plate, the perfluorooctanoic acid solution was controlled to be 10 mg / L, the discharge voltage was kept at 7 kV, and the discharge distance was kept at 3 mm. Sample solutions were collected after 15, 30, 45, and 60 minutes of discharge reaction.
[0036] Ion chromatography analysis was performed on the sample solutions after different reaction times in Example 1. To avoid damage to the instrument due to excessive concentration, all collected solutions were diluted 10 times with deionized water before analysis. The fluoride ion concentration generated during the degradation of perfluorooctanoic acid was measured using an ion chromatograph equipped with an AS11-HC column. No obvious chromatographic peak was detected in the perfluorooctanoic acid standard solution before the reaction. As the reaction time increased, it was clearly observed that the fluoride ion chromatographic peak intensity gradually increased ( Figure 2 In (a), after 60 min of degradation, the fluoride ion concentration was approximately 0.508 mg / L, demonstrating the strong defluorination potential of water radical cations.
[0037] Example 2
[0038] use Figure 1 In the degradation device, 6 mL of perfluorooctanoic acid solution was placed in the negative electrode plate, the perfluorooctanoic acid solution was controlled to be 50 mg / L, the discharge voltage was kept at 7 kV, and the discharge distance was kept at 3 mm. The sample solution was collected after the discharge reaction lasted for 60 minutes.
[0039] The sample solutions before and after the reaction in Example 2 were diluted 10 times and then subjected to electrospray ionization mass spectrometry analysis. Figure 2 As shown in b, before the reaction, the characteristic ion peak of m / z 413 can be clearly detected in the perfluorooctanoic acid standard solution in the negative ion mode, with a signal intensity of 1.4×10 6 After 60 min of reaction, the peak intensity decreased to 1.3×10 3 , indicating that perfluorooctanoic acid has undergone significant degradation, with a calculated degradation rate of approximately 96.47%. At the same time, defluorohydroxylation product ions m / z 411 and m / z 409 were detected, and their structures were further determined by tandem mass spectrometry analysis. The data results are as follows: Figure 2 Images c and d both show the typical loss of H2O and CO2 characteristic ions. Subsequently, the secondary hydroxylation product (m / z 409) further loses HF to form an intermediate (m / z 389). This intermediate undergoes a series of de-CF2 carbon chain shortening processes to produce several short-chain products (m / z 339, m / z 289, m / z 239, m / z 189, and m / z 139). In addition, several short-chain perfluorocarboxylic acids are clearly detected, such as undecafluorohexanoic acid (m / z 313), nonafluoropentanoic acid (m / z 263), heptafluorobutanoic acid (m / z 213), and pentafluoropropionic acid (m / z 163).
[0040] Example 3
[0041] use Figure 1In the degradation device, 6 mL of PFOS solution was placed in the negative electrode plate, the PFOS solution was controlled to be 50 mg / L, the discharge voltage was kept constant at 7 kV, and the discharge distance was kept constant at 3 mm. The sample solution was collected after the discharge reaction lasted for 60 minutes.
[0042] The sample solutions before and after the reaction of Example 3 were diluted 10 times and subjected to electrospray ionization mass spectrometry analysis. It can be observed that after 60 minutes of discharge treatment, almost no m / z 499 signal is detected, while its secondary hydroxylation degradation product (m / z 495) is the base peak. In addition, the hydroxylation product (m / z 495), the product of HF removal (m / z 475) and the subsequent de-CF2 products (m / z 425, m / z 375, m / z 325, m / z 275, m / z 225 and m / z 175) can all be clearly captured ( Figure 3 ).
[0043] In summary, this invention demonstrates the enormous potential of water radical cations for pollutant degradation through a custom-made multi-needle array discharge device. This technology is simple to operate and can achieve efficient degradation of perfluorinated compounds without the need for catalysts. It provides new scientific evidence and technical support for water pollution control and has significant application prospects.
[0044] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
[0045] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.
Claims
1. A method for degrading perfluorinated compounds, characterized in that: A perfluorinated compound solution of a certain concentration and volume is placed in a discharge reaction device. By regulating the discharge, the water vapor will be ionized to form water radical cations and their clusters. The water radical cations can effectively react with the perfluorinated compound, thereby achieving its degradation.
2. The method for degrading a perfluorinated compound according to claim 1, wherein: The perfluorinated compound is perfluorooctanoic acid and / or perfluorooctane sulfonic acid.
3. The method for degrading a perfluorinated compound according to claim 1, wherein: The discharge reaction device comprises a high-voltage power supply device, a corona discharge array device and a negative plate. The corona discharge array device is connected to the positive electrode of the high-voltage power supply device, and the negative plate is connected to the negative electrode of the high-voltage power supply device.
4. The method for degrading a perfluorinated compound according to claim 3, wherein: The corona discharge array device includes an array plate and corona discharge needles located below the array plate.
5. The method for degrading a perfluorinated compound according to claim 3, wherein: The negative electrode plate is made of stainless steel.
6. The method for degrading a perfluorinated compound according to claim 1, wherein: The concentration of the perfluorinated compound solution is 10 to 200 mg / L.
7. The method for degrading a perfluorinated compound according to claim 1, wherein: The volume of the perfluorinated compound solution is 5-7 mL.
8. The method for degrading a perfluorinated compound according to claim 1, wherein: The discharge voltage is between 4.0 and 7.0 kV.
9. The method for degrading a perfluorinated compound according to claim 3, wherein: The distance between the tip of the corona discharge needle and the negative electrode plate is between 3 and 9 mm.