A friction-catalytic fabric loaded with polytetrafluoroethylene coating and its application

Abstract

This invention discloses a PTFE-coated tribocatalytic fabric and its application. The PTFE-coated tribocatalytic fabric comprises a PTFE coating and a porous fabric layer. The PTFE coating comprises 0.2% to 1.1% by mass, with the remainder being the porous fabric layer. The porous fabric layer is composed of natural fiber fabrics such as cotton, linen, and polyester, or synthetic fiber fabrics. This invention sprays PTFE onto the fabric surface, preserving the original macroporous structure of the fabric while ensuring strong adhesion between the PTFE spray and the fabric. This combines the stress amplification effect of the fabric with the tribocatalytic properties of PTFE, increasing the stress on the PTFE surface during friction, thereby improving the tribocatalytic effect. The PTFE-coated tribocatalytic fabric of this invention has advantages such as high chemical stability and strong performance in improving friction efficiency. When used for the catalytic degradation of dyes, it offers advantages such as high degradation rate (>90%), low cost, recyclability, and environmental friendliness, and is expected to be practically applied in the future to degrade organic pollutants in wastewater.

Description

Technical Field

[0001] This invention belongs to the field of catalysis technology, specifically relating to a supported polytetrafluoroethylene (PTFE) coated tribocatalytic fabric and its application. Background Technology

[0002] Triboelectricity refers to the phenomenon where two objects with different charges transfer their outermost electrons during friction, resulting in both acquiring equal amounts of opposite charges. Utilizing this phenomenon to provide mechanical energy and free charges for catalytic reactions forms tribocatalysis. Catalytic materials are the core of catalytic technology, and catalytic performance, reusability, and environmental friendliness are crucial factors significantly influencing a material's application potential. PTFE is a material with excellent triboelectric properties and strong chemical stability, possessing good tribocatalytic and reusability performance. Furthermore, this material is easily recyclable and does not easily cause environmental pollution. These characteristics give PTFE broad application prospects in tribocatalysis. Currently, PTFE has been reported for tribocatalytic degradation of dyes. The main approach involves achieving high dye degradation rates through high-frequency mechanical energy such as ultrasound in solid-solid friction. However, using high-frequency mechanical energy consumes significant energy. On the other hand, because high-frequency mechanical energy is not common in nature, the implementation scenarios for this tribocatalysis scheme are limited, leaving room for improvement in practicality. Therefore, utilizing low-frequency mechanical energy to achieve tribocatalytic degradation of dyes has significant research and application value, but reports on low-frequency tribocatalysis, especially solid-liquid tribocatalysis, are still relatively few.

[0003] To further ensure high reaction efficiency while reducing catalytic reaction energy consumption, it is necessary to enhance low-frequency tribocatalysis from angles other than energy input. The friction efficiency between materials is a key factor affecting tribocatalytic performance. Therefore, finding a simple method to enhance friction between materials is of great significance to the development of low-frequency tribocatalysis. Improving the friction pathway is beneficial to promoting friction between materials. Porous fabrics possess a macroporous structure with abundant stress concentration sites. They can amplify the stress of the liquid when it passes through the fabric. If the catalytic material is loaded onto the fabric surface, it is hoped that the stress amplification effect of the fabric can be used to increase the frictional force on the catalytic material, thereby promoting solid-liquid friction and enhancing tribocatalysis. This method is not only simple to operate, but also provides a reference for the integration of the textile industry with tribocatalysis technology, and has good development prospects in the field of organic wastewater treatment (such as the degradation of organic dyes). Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of high energy consumption and limited application scenarios of current tribocatalytic dye degradation technology, and to provide a PTFE-coated tribocatalytic fabric to promote friction between PTFE and dye, thereby enhancing the effect of tribocatalytic dye degradation.

[0005] To achieve the above objectives, the PTFE-coated tribocatalytic fabric provided by the present invention comprises: a polytetrafluoroethylene coating and a porous fabric layer, wherein the mass percentage of the polytetrafluoroethylene coating is 0.2% to 1.1%, and the mass percentage of the porous fabric layer is 98.9% to 99.8%.

[0006] The aforementioned polytetrafluoroethylene coating is a Teflon plastic that can withstand temperatures of -200 to 260°C and pH ranges of 0 to 14, with a thickness of 5 to 20 μm.

[0007] The aforementioned porous fabric layer is composed of any one or more fabrics selected from cotton, linen, polyester, and synthetic fibers. The diameter of the textile threads in the porous fabric layer is 0.1–0.5 mm, and the pore size ranges from 0.5–10 μm.

[0008] The polytetrafluoroethylene-coated friction catalytic fabric of the present invention is made by spraying polytetrafluoroethylene spray onto both sides of a porous fabric layer and bonding them together at ambient temperature.

[0009] The present invention also provides the use of the aforementioned polytetrafluoroethylene-coated tribocatalytic fabric in dye degradation. The specific method is as follows: the polytetrafluoroethylene-coated tribocatalytic fabric is attached to the bottom end of the stirring paddle of a cantilevered electric stirrer, so that it is completely immersed in the dye solution. The stirrer is turned on, so that the polytetrafluoroethylene-coated tribocatalytic fabric is rubbed against the dye solution under stirring conditions to achieve dye degradation.

[0010] The dyes mentioned above are any one or more of Rhodamine B (RhB), methylene blue (MB), and methyl orange (MO).

[0011] In the application of the above-mentioned polytetrafluoroethylene-coated tribocatalytic fabric in dye degradation, the rotation speed of the stirring paddle is preferably controlled at 1000-1500 rpm.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] 1. This invention utilizes the macroporous structure of porous fabrics to enhance the performance of PTFE in tribocatalytic degradation of dyes. By spraying PTFE onto the fabric surface, the stress amplification effect generated by the fabric's macroporous structure increases the stress experienced by PTFE during friction, thereby improving the solid-liquid tribocatalytic efficiency. The PTFE-coated tribocatalytic fabric of this invention has advantages such as high chemical stability and high dye catalytic degradation rate (>90%).

[0014] 2. This invention combines recycled waste porous fabrics with PTFE spray to achieve tribocatalytic degradation of dyes. Waste fabrics have advantages such as abundant quantity, wide availability, and low cost. The controllability of porous fabrics also provides conditions for further optimization of this invention. At the same time, recycling waste materials helps improve the economic benefits and environmental friendliness of tribocatalytic dye degradation, providing a solution for achieving the green governance goal of "treating waste with waste".

[0015] 3. This invention achieves effective tribocatalytic dye degradation through the simple method of stirring. A PTFE-coated tribocatalytic fabric is adhered to the bottom of the impeller of a cantilevered electric stirrer, immersing it in the dye solution. Under high-speed stirring, the dye solution passes through the large pores of the fabric, generating a greater impact on the PTFE on the fabric surface, thereby increasing the frictional stress at the solid-liquid interface. Through triboelectric effect, PTFE and the dye solution acquire equal amounts of opposite charges due to their different charging capacities. These charges further undergo redox reactions with water and dissolved oxygen, generating hydroxyl radicals (·OH) and superoxide radicals (·O2). - Active free radicals such as α and β are used. Finally, the dye is degraded by free radicals. This method has the advantages of simple operation and low cost. Attached Figure Description

[0016] Figure 1 These are SEM images of the original polyester fabric (a) and the PTFE-coated tribocatalytic fabric prepared in Example 1 (b).

[0017] Figure 2 This is the XRD pattern of the PTFE-coated tribocatalytic fabric prepared in Example 1.

[0018] Figure 3 This is a graph showing the RhB degradation rate of the PTFE-coated tribocatalytic fabric and the non-porous PTFE film prepared in Example 1.

[0019] Figure 4 This is a graph showing the degradation rate of RhB by the PTFE-coated tribocatalytic fabric prepared in Example 1 at different stirring speeds.

[0020] Figure 5 This is a graph showing the degradation rate of RhB on the PTFE-coated tribocatalytic fabric prepared in Example 1 under different PTFE spraying qualities.

[0021] Figure 6 This is a bar chart showing the degradation rates of RhB, MB, and MO by the PTFE-coated tribocatalytic fabric prepared in Example 1. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] The PTFE-coated tribocatalytic fabric of this embodiment includes a PTFE coating and a porous fabric layer. The PTFE coating has a mass percentage of 1.0%, and the porous fabric layer has a mass percentage of 99.0%. The PTFE coating is a Teflon plastic with a temperature tolerance of -200 to 260°C and a pH tolerance of 0 to 14, and its thickness is 5 μm. The porous fabric layer is composed of polyester fabric, where the diameter of the woven threads is 0.4 mm and the average pore size is 5 μm. The preparation method of the PTFE-coated tribocatalytic fabric is as follows: the polyester fabric is placed horizontally, and at ambient temperature, PTFE spray is directed at both sides of the polyester fabric to form a moist PTFE coating; subsequently, the polyester fabric is placed horizontally in a ventilated area and allowed to air dry naturally to obtain the PTFE-coated tribocatalytic fabric.

[0025] The microstructures of the original polyester fabric and the PTFE-coated tribocatalytic fabric are as follows: Figure 1 As shown. The original polyester fabric possesses a rich macroporous structure (…). Figure 1 a). After PTFE spraying, while the surface of the polyester fabric is covered by the PTFE coating, the original large pores of the polyester fabric are preserved. Figure 1 b). For example Figure 2 As shown, the (100), (111), (107), (108), (210), and (300) crystal plane peaks of the PTFE-coated tribocatalytic fabric correspond exactly to the PTFE standard card. Furthermore, the semi-circular peaks in the XRD pattern correspond to the semi-crystalline structure of the polyester raw material in the porous fabric. These results demonstrate that the PTFE coating was successfully loaded onto the surface of the porous polyester fabric, and the tribocatalytic fabric was well-prepared.

[0026] Example 2

[0027] This embodiment uses a PTFE-coated fabric to tribocatalyze the degradation of dyes, investigates the influencing factors on the performance of tribocatalytic dye degradation, and tests the enhancing effect of the fabric's macroporous structure on the performance of tribocatalytic dye degradation.

[0028] 1. Application methods of PTFE-coated tribocatalytic fabrics

[0029] First, a PTFE-coated triboelectric catalytic fabric is attached to the bottom of the impeller of a cantilevered electric stirrer and immersed in an RhB aqueous solution. The stirrer is then started, and the PTFE-coated triboelectric catalytic fabric is thoroughly rubbed against the RhB aqueous solution at a specific stirring speed. Under the influence of triboelectric electrostatics, this process causes the PTFE and RhB aqueous solution, which have different electronegativity, to acquire equal amounts of negative and positive charges, respectively. Finally, these charges generated through friction react with water and dissolved oxygen in the solution in a redox reaction, producing ·OH and ·O2. - Active free radicals are used to achieve tribocatalytic degradation of dyes.

[0030] 2. Factors affecting the performance of tribocatalytic degradation of dyes

[0031] Following the method described in Experiment 1 above, the effects of stirring speed, PTFE coating quality, and dye type on the performance of tribocatalytic dye degradation were investigated. Simultaneously, a comparative experiment was conducted using a PTFE film with a non-porous surface to analyze the enhancing effect of the fabric's macroporous structure on the tribocatalytic dye degradation process.

[0032] (1) Investigate the effect of fabric macroporous structure on the performance of tribocatalytic dye degradation. Figure 3 It was found that, under the conditions of a rotation speed of 1200 rpm, a PTFE coating mass of 1.1 g (corresponding to a mass percentage of 0.8%) on a polyester fabric (size 5.5 cm × 1 cm, weave thread diameter 0.4 mm, average pore size 5 μm), and an ambient temperature of 25℃, the degradation efficiency of RhB by the PTFE-coated tribocatalytic fabric (94.6% degradation in 2 hours) was significantly higher than that of the non-porous PTFE film (52.4% degradation in 2 hours). This result confirms the enhancing effect of the original fabric's macroporous structure on the tribocatalytic degradation performance of RhB dyes.

[0033] (2) Investigate the effect of PTFE spraying quality on the performance of tribocatalytic degradation of dyes. Figure 4It was found that under conditions of 1200 rpm and an ambient temperature of 25℃, PTFE was uniformly sprayed onto eight 5.5 cm × 1 cm polyester fabrics (weaving thread diameter of 0.4 mm and average pore size of 5 μm). When the PTFE spraying mass increased from 0.5 g (corresponding to 0.2% by mass) to 1.1 g (corresponding to 0.8% by mass), the degradation performance of RhB (10 mg / L) on the PTFE-coated tribocatalytic fabric improved. When the PTFE spraying mass was 1.1 g (corresponding to 0.8% by mass), the degradation rate of RhB reached its maximum (94.6%) after 120 min; when the PTFE spraying mass was further increased to 1.4 g (corresponding to 1.1% by mass), the degradation rate of RhB decreased slightly to 89.1%. This phenomenon can be attributed to the excessive PTFE coating covering the original fabric's macroporous structure, thereby inhibiting the enhancing effect of the macroporous structure on the tribocatalytic degradation of dyes.

[0034] (3) Investigate the effect of stirring speed on the performance of tribocatalytic degradation of dyes. Figure 5 It was found that under the conditions of 1.1 g of PTFE coating (corresponding to 0.8% by mass) on polyester fabric (size 5.5cm×1cm, weave thread diameter 0.4mm, average pore size 5μm) and an ambient temperature of 25℃, the degradation performance of RhB (10mg / L) on the PTFE-coated tribocatalytic fabric improved accordingly when the stirring speed increased from 800rpm to 1200rpm. At a stirring speed of 1200rpm, the degradation rate of RhB reached its maximum of 94.9% after 120min. However, further increasing the stirring speed to 1400rpm resulted in a decrease in the degradation rate of RhB. This is because at higher stirring speeds, the RhB aqueous solution exhibits turbulence, which inhibits effective contact and friction between PTFE and the dye solution, thus reducing the performance of tribocatalytic degradation of RhB.

[0035] (4) Investigate the effect of dye type on the performance of tribocatalytic dye degradation. Figure 6It was found that under the conditions of a rotation speed of 1200 rpm, a PTFE coating mass of 1.1 g (corresponding to a mass percentage of 0.8%) on a polyester fabric (size 5.5 cm × 1 cm, weave thread diameter 0.4 mm, average pore size 5 μm), and an ambient temperature of 25℃, the degradation rates of RhB, MB, and MO (all 5 mg / L) on the PTFE-coated triboelectric catalytic fabric after 120 min were 85.7%, 77.6%, and 19.1%, respectively. The degradation rates of MB and MO were significantly lower than those of RhB. This is because, compared to RhB molecules, MB and MO molecules contain more high-energy chemical bonds such as C=N and N=N, which require higher energy to be broken down, thus significantly increasing the difficulty of degradation of MB and MO under the same reaction conditions.

Claims

1. A tribocatalytic fabric supported on a polytetrafluoroethylene coating, characterized in that, include: The product comprises a polytetrafluoroethylene (PTFE) coating and a porous fabric layer, wherein the PTFE coating comprises 0.2% to 1.1% by mass, and the porous fabric layer comprises 98.9% to 99.8% by mass; the PTFE coating has a thickness of 5 to 20 μm; the diameter of the textile threads in the porous fabric layer is 0.1 to 0.5 mm, and the pore size ranges from 0.5 to 10 μm; the PTFE-coated friction catalytic fabric is prepared by spraying PTFE spray onto both sides of the porous fabric layer and bonding them together at ambient temperature.

2. The polytetrafluoroethylene-coated tribocatalytic fabric according to claim 1, characterized in that, The polytetrafluoroethylene coating is a Teflon plastic that can withstand temperatures of -200 to 260°C and pH ranges of 0 to 14.

3. The polytetrafluoroethylene-coated tribocatalytic fabric according to claim 1, characterized in that, The porous fabric layer is composed of any one or more fabrics selected from cotton, linen, and synthetic fibers.

4. The use of the polytetrafluoroethylene-coated tribocatalytic fabric according to claim 1 in dye degradation.

5. The use of the polytetrafluoroethylene-coated tribocatalytic fabric according to claim 4 in dye degradation, characterized in that, The PTFE-coated tribocatalytic fabric is attached to the bottom of the agitator of a cantilevered electric stirrer, so that it is completely immersed in the dye solution. The stirrer is turned on, so that the PTFE-coated tribocatalytic fabric is rubbed against the dye solution under stirring conditions to degrade the dye.

6. The use of the polytetrafluoroethylene-coated tribocatalytic fabric according to claim 4 or 5 in dye degradation, characterized in that, The dye is any one or more of Rhodamine B, methylene blue, and methyl orange.

7. The use of the polytetrafluoroethylene-coated tribocatalytic fabric according to claim 5 in dye degradation, characterized in that, The rotational speed of the agitator is controlled between 1000 and 1500 rpm.

Images