A method for preparing a silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst

Abstract

This invention belongs to the field of environmental material preparation technology, and specifically relates to a method for preparing a silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst, comprising the following steps: A. Mixing carbon fiber with bismuth nitrate solution to react and obtain bismuth oxide / carbon fiber; B. Reacting the bismuth oxide / carbon fiber obtained in step A with bismuth nitrate solution and hexadecyltrimethylammonium chloride solution to obtain bismuth oxychloride / bismuth oxide / carbon fiber; C. Taking the bismuth oxychloride / bismuth oxide / carbon fiber obtained in step B, carrying out a photoreduction reaction in silver nitrate solution, and obtaining a flexible silver / bismuth oxychloride / bismuth oxide / carbon fiber photocatalyst after washing and drying.

Description

Technical Field

[0001] This invention belongs to the field of environmental material preparation technology, and specifically relates to a method for preparing a silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst. Background Technology

[0002] The rapid industrialization and socio-economic development have led to a dramatic increase in industrial wastewater discharge, placing immense pressure on the Earth's ecosystem. Adsorption is a common wastewater treatment technology, but adsorbents can only collect pollutants in the solid phase, easily causing secondary pollution during reuse. In contrast, photocatalytic degradation technology utilizes sunlight to directly eliminate organic pollutants, making it more environmentally friendly. However, photocatalysts have limited ability to capture pollutant molecules from water, restricting their kinetic processes and resulting in insufficient overall treatment efficiency. Furthermore, traditional photocatalytic materials are mostly powders, making recycling difficult and resulting in significant losses, hindering their reuse in practical applications. Summary of the Invention

[0003] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0004] This application provides a method for preparing a silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst, comprising the following steps:

[0005] A. Mix carbon fiber with bismuth nitrate solution to react and obtain bismuth oxide / carbon fiber;

[0006] B. React the bismuth oxide / carbon fiber obtained in step A with bismuth nitrate solution and hexadecyltrimethylammonium chloride solution to obtain bismuth oxychloride / bismuth oxide / carbon fiber;

[0007] C. Take the bismuth oxychloride / bismuth oxide / carbon fiber obtained in step B, carry out a photoreduction reaction in silver nitrate solution, and obtain a flexible composite photocatalyst of silver / bismuth oxychloride / bismuth oxide / carbon fiber after washing and drying.

[0008] In some embodiments, in step A, the bismuth nitrate solution is a bismuth nitrate / ethylene glycol solution with a concentration of 0.1-0.2 mol / L.

[0009] In some embodiments, step A further includes anhydrous ethanol, wherein the volume ratio of the bismuth nitrate / ethylene glycol solution to the anhydrous ethanol is 1:2.

[0010] In some embodiments, in step A, the reaction temperature is 160°C and the reaction time is 300 min.

[0011] In some embodiments, in step B, the volume ratio of the bismuth nitrate solution to the hexadecyltrimethylammonium chloride solution is 1:3.

[0012] In some embodiments, the bismuth nitrate solution is a bismuth nitrate / ethylene glycol solution with a concentration of 0.0618 mol / L.

[0013] In some embodiments, the hexadecyltrimethylammonium chloride solution is a hexadecyltrimethylammonium chloride / ethanol solution with a concentration of 0.03514 mol / L.

[0014] In some embodiments, in step B, the reaction temperature is 160°C and the reaction time is 240 min.

[0015] In some embodiments, in step C, the photoreduction reaction is carried out under xenon lamp irradiation, and the power of the xenon lamp is 300W.

[0016] In some embodiments, the concentration of the silver nitrate solution is 0.05-0.2 mol / L, and the reaction time is 10-30 min.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] This invention loads a metal-modified semiconductor heterostructure onto a carbon fiber substrate. First, the construction of the semiconductor heterostructure significantly improves the separation of photogenerated electron-hole pairs and reduces the recombination of photogenerated carriers, thereby enhancing photocatalytic efficiency. Second, the formation of the metal-semiconductor heterostructure interface increases the conductive pathways in the system, promoting the transport of photogenerated carriers and improving photocatalytic activity. Furthermore, using carbon fiber as the substrate allows the photocatalyst to exist in the form of a fiber film, facilitating recycling. The conductivity of the carbon fiber also aids in the separation of photogenerated carriers, further contributing to improved photocatalytic efficiency.

[0019] Specifically, this invention uses carbon fiber as a supporting substrate and obtains a silver-modified carbon fiber-based bismuth oxychloride / bismuth oxide heterojunction composite photocatalyst through a two-step solvothermal method and photoreduction reaction, which has the following effects:

[0020] (1) Bismuth oxychloride has chemical adsorption capacity, which can enhance the photocatalyst's ability to capture pollutant molecules.

[0021] (2) The formation of bismuth oxychloride / bismuth oxide heterojunction can redistribute photogenerated carriers in space, reduce the recombination of photogenerated carriers, and improve the photocatalytic degradation efficiency.

[0022] (3) Silver modification can increase the conductive pathways in the system, promote the migration of photogenerated carriers, reduce recombination, and thus improve the photocatalytic degradation efficiency;

[0023] (4) Carbon fiber can provide a conductive support framework for the system, which is conducive to the cycle stability of the material, and also makes the photocatalyst easy to recycle, thus solving the problem that traditional powder photocatalysts are difficult to recycle and reuse.

[0024] (5) The preparation method is simple, low-cost and will not cause pollution to the environment. Attached Figure Description

[0025] Figure 1a This is a SEM image of the carbon fiber in Embodiment 1 of this application;

[0026] Figure 1b This is a SEM image of the bismuth oxide / carbon fiber prepared in Example 1 of this application;

[0027] Figure 1c This is a SEM image of the bismuth oxychloride / bismuth oxide / carbon fiber prepared in Example 1 of this application;

[0028] Figure 1d SEM image of the silver / bismuth oxychloride / bismuth oxide / carbon fiber prepared in Example 1 of this application;

[0029] Figure 2 The photocatalytic degradation curves of 10 mg / L Rhodamine B by bismuth oxide / carbon fiber, bismuth oxychloride / bismuth oxide / carbon fiber, and silver / bismuth oxychloride / bismuth oxide / carbon fiber prepared in Example 1 of this application are shown.

[0030] Figure 3 The photocatalytic degradation curves of 10 mg / L Rhodamine B by silver / bismuth oxychloride / bismuth oxide / carbon fiber, silver / bismuth oxychloride / bismuth oxide / carbon fiber, and silver / bismuth oxychloride / bismuth oxide / carbon fiber prepared in Examples 2, 1, and 3 of this application are shown.

[0031] Figure 4 The cyclic degradation curve of 10 mg / L Rhodamine B by the silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst prepared in Example 1 of this application is shown.

[0032] Figure 5 This is a comparison diagram showing the degradation of 10 mg / L Rhodamine B by the silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst prepared in Example 1 of this application and the bismuth oxide powder prepared in Comparative Example 1. Detailed Implementation

[0033] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0034] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. The exemplary embodiments disclosed herein should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations caused, for example, by manufacturing processes. For example, etched regions shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0035] Example 1

[0036] A. Dissolve 1.818 g of bismuth nitrate pentahydrate in 25 mL of ethylene glycol to form a 0.15 mol / L bismuth nitrate / ethylene glycol solution. Place the electrospun fiber membrane in a Teflon-lined reactor. Then, mix the bismuth nitrate / ethylene glycol solution and anhydrous ethanol at a volume ratio of 1:2. Place the reactor in a forced-air drying oven and carry out a hydrothermal reaction at 160 °C for 300 min. The resulting fiber membrane is washed repeatedly with anhydrous ethanol 5 times and dried in a forced-air drying oven at 60 °C for 12 h to obtain bismuth oxide / carbon fiber.

[0037] B. Dissolve 0.75g of bismuth nitrate pentahydrate in 25mL of ethylene glycol to form a 0.618mol / L bismuth nitrate / ethylene glycol solution. Then dissolve 0.75g of hexadecyltrimethylammonium chloride in 67mL of anhydrous ethanol to form a 0.035mol / L hexadecyltrimethylammonium chloride / ethanol solution. Add the bismuth oxide / carbon fiber obtained in step A to a Teflon reactor, and then add the bismuth nitrate / ethylene glycol solution and the hexadecyltrimethylammonium chloride / ethanol solution at a volume ratio of 1:3 respectively. After mixing evenly, place the reactor in a forced-air drying oven and carry out a hydrothermal reaction at 160℃ for 240min. The resulting fiber membrane is washed repeatedly with anhydrous ethanol 5 times and dried in a forced-air drying oven at 60℃ for 12h to obtain bismuth oxychloride / bismuth oxide / carbon fiber.

[0038] C. Dissolve 0.169 g of silver nitrate in 10 mL of deionized water to form a 0.1 mol / L silver nitrate aqueous solution. Add 10 mL of the prepared silver nitrate solution to a quartz test tube, then add the bismuth oxychloride / bismuth oxide / carbon fiber obtained in step B. Perform a photoreduction reaction under a 300 W xenon lamp for 20 min. The resulting fiber membrane is repeatedly washed with deionized water 5 times and dried in a forced-air drying oven at 60 °C for 12 h to obtain the silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst.

[0039] Example 2

[0040] A. Dissolve 1.212 g of bismuth nitrate pentahydrate in 25 mL of ethylene glycol to form a 0.10 mol / L bismuth nitrate / ethylene glycol solution. Place the electrospun fiber membrane in a Teflon-lined reactor. Then, mix the bismuth nitrate / ethylene glycol solution and anhydrous ethanol at a volume ratio of 1:2. Place the reactor in a forced-air drying oven and carry out a hydrothermal reaction at 160 °C for 300 min. The resulting fiber membrane is washed repeatedly with anhydrous ethanol 5 times and dried in a forced-air drying oven at 60 °C for 12 h to obtain bismuth oxide / carbon fiber.

[0041] B. Dissolve 0.75g of bismuth nitrate pentahydrate in 25mL of ethylene glycol to form a 0.618mol / L bismuth nitrate / ethylene glycol solution. Then dissolve 0.75g of hexadecyltrimethylammonium chloride in 67mL of anhydrous ethanol to form a 0.035mol / L hexadecyltrimethylammonium chloride / ethanol solution. Add the bismuth oxide / carbon fiber obtained in step A to a Teflon reactor, and then add the bismuth nitrate / ethylene glycol solution and the hexadecyltrimethylammonium chloride / ethanol solution at a volume ratio of 1:3 respectively. After mixing evenly, place the reactor in a forced-air drying oven and carry out a hydrothermal reaction at 160℃ for 240min. The resulting fiber membrane is washed repeatedly with anhydrous ethanol 5 times and dried in a forced-air drying oven at 60℃ for 12h to obtain bismuth oxychloride / bismuth oxide / carbon fiber.

[0042] C. Dissolve 0.169 g of silver nitrate in 10 mL of deionized water to form a 0.1 mol / L silver nitrate aqueous solution. Add 10 mL of the prepared silver nitrate solution to a quartz test tube, then add the bismuth oxychloride / bismuth oxide / carbon fiber obtained in step B. Perform a photoreduction reaction under a 300 W xenon lamp for 20 min. The resulting fiber membrane is repeatedly washed with deionized water 5 times and dried in a forced-air drying oven at 60 °C for 12 h to obtain the silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst.

[0043] Example 3

[0044] A. Dissolve 2.424 g of bismuth nitrate pentahydrate in 25 mL of ethylene glycol to form a 0.20 mol / L bismuth nitrate / ethylene glycol solution. Place the electrospun fiber membrane in a Teflon-lined reactor. Then, mix the bismuth nitrate / ethylene glycol solution and anhydrous ethanol at a volume ratio of 1:2. Place the reactor in a forced-air drying oven and carry out a hydrothermal reaction at 160 °C for 300 min. The resulting fiber membrane is washed repeatedly with anhydrous ethanol 5 times and dried in a forced-air drying oven at 60 °C for 12 h to obtain bismuth oxide / carbon fiber.

[0045] B. Dissolve 0.75g of bismuth nitrate pentahydrate in 25mL of ethylene glycol to form a 0.618mol / L bismuth nitrate / ethylene glycol solution. Then dissolve 0.75g of hexadecyltrimethylammonium chloride in 67mL of anhydrous ethanol to form a 0.035mol / L hexadecyltrimethylammonium chloride / ethanol solution. Add the bismuth oxide / carbon fiber obtained in step A to a Teflon reactor, and then add the bismuth nitrate / ethylene glycol solution and the hexadecyltrimethylammonium chloride / ethanol solution at a volume ratio of 1:3 respectively. After mixing evenly, place the reactor in a forced-air drying oven and carry out a hydrothermal reaction at 160℃ for 240min. The resulting fiber membrane is washed repeatedly with anhydrous ethanol 5 times and dried in a forced-air drying oven at 60℃ for 12h to obtain bismuth oxychloride / bismuth oxide / carbon fiber.

[0046] C. Dissolve 0.169 g of silver nitrate in 10 mL of deionized water to form a 0.1 mol / L silver nitrate aqueous solution. Add 10 mL of the prepared silver nitrate solution to a quartz test tube, then add the bismuth oxychloride / bismuth oxide / carbon fiber obtained in step B. Perform a photoreduction reaction under a 300 W xenon lamp for 20 min. The resulting fiber membrane is repeatedly washed with deionized water 5 times and dried in a forced-air drying oven at 60 °C for 12 h to obtain the silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst.

[0047] Comparative Example 1

[0048] 1.818 g of bismuth nitrate pentahydrate was dissolved in 25 mL of ethylene glycol to form a 0.15 mol / L bismuth nitrate / ethylene glycol solution. The bismuth nitrate / ethylene glycol solution and anhydrous ethanol were mixed at a volume ratio of 1:2, and the reaction vessel was placed in a forced-air drying oven for a hydrothermal reaction at 160 °C for 300 min. After the reaction was complete, the product was washed three times with anhydrous ethanol by centrifugation and then dried in a forced-air drying oven at 60 °C for 12 h to obtain bismuth oxide powder.

[0049] Test case

[0050] Figures 1a to 1d Scanning electron microscope (SEM) images are shown for carbon fiber, bismuth oxide / carbon fiber prepared in Example 1, bismuth oxychloride / bismuth oxide / carbon fiber, and silver / bismuth oxychloride / bismuth oxide / carbon fiber, respectively. After the first hydrothermal treatment, the carbon fiber diameter increased, the surface became rougher, and it was coated with particles. After the second hydrothermal treatment, the fibers in the bismuth oxychloride / bismuth oxide / carbon fiber were coated with a large number of nanosheets. After silver was modified by photoreduction, the surface morphology of the sample did not change significantly. The large number of nanosheets coating the surface of the silver / bismuth oxychloride / bismuth oxide / carbon fiber exposed more surface area of ​​the sample, which is beneficial for sufficient contact with the contaminant solution during the reaction.

[0051] Figure 2The photocatalytic degradation curves of 10 mg / L Rhodamine B by the bismuth oxide / carbon fiber, bismuth oxychloride / bismuth oxide / carbon fiber, and silver / bismuth oxychloride / bismuth oxide / carbon fiber prepared in Example 1 are shown. After light-shielded adsorption and 120 min of photodegradation, the removal rate of Rhodamine B by bismuth oxide / carbon fiber was 35.7%; the removal rate of Rhodamine B by bismuth oxychloride / bismuth oxide / carbon fiber was 78.9%. This performance improvement is partly due to the formation of the bismuth oxychloride / bismuth oxide heterojunction, which spatially separates photogenerated electron-hole pairs and reduces the recombination of photogenerated carriers.

[0052] On the other hand, the chemisorption of Rhodamine B by bismuth oxychloride enhances the photocatalyst's ability to capture organic pollutant molecules, thus improving photocatalytic activity. The silver / bismuth oxychloride / bismuth oxide / carbon fiber combination achieved a 91.1% removal rate for Rhodamine B, with further improvements in degradation performance attributed to silver modification. This increased the conductive pathways within the system, promoting the migration of photogenerated carriers, reducing recombination, and further enhancing photocatalytic degradation efficiency. In summary, through the combination of adsorption and degradation, the construction of heterojunctions, and silver modification, the silver / bismuth oxychloride / bismuth oxide / carbon fiber combination significantly enhances the removal efficiency of pollutants, enabling efficient removal of organic pollutants from water.

[0053] Figure 3 The photocatalytic degradation curves of 10 mg / L Rhodamine B by the silver / bismuth oxychloride / bismuth oxide / carbon fiber, silver / bismuth oxychloride / bismuth oxide / carbon fiber, and silver / bismuth oxychloride / bismuth oxide / carbon fiber prepared in Examples 2, 1, and 3, respectively, are shown. After equilibration adsorption and 120 min of photodegradation, the removal rates of Rhodamine B by the silver / bismuth oxychloride / bismuth oxide / carbon fiber, silver / bismuth oxychloride / bismuth oxide / carbon fiber, and silver / bismuth oxychloride / bismuth oxide / carbon fiber prepared in Examples 2, 1, and 3 were 88.2%, 91.1%, and 84.9%, respectively. The silver / bismuth oxychloride / bismuth oxide / carbon fiber prepared in Example 1 showed the highest removal rate of Rhodamine B.

[0054] Figure 4 The image shows the cyclic degradation curve of 10 mg / L Rhodamine B by the silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst prepared in Example 1. During the cycling process, the photocatalytic activity of the photocatalyst only decreased slightly, indicating that the photocatalyst has good cyclic stability.

[0055] Figure 5The images show a comparison of the silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst prepared in Example 1 and the bismuth oxide powder prepared in Comparative Example 1 before and after degradation of 10 mg / L Rhodamine B. For the powder group, although the solution color faded after degradation, the bismuth oxide powder remained suspended in the solution, requiring complex separation steps to obtain a clear solution. For the carbon fiber group, after degradation by silver / bismuth oxychloride / bismuth oxide / carbon fiber, the solution was colorless and clear, allowing for direct extraction of the silver / bismuth oxychloride / bismuth oxide / carbon fiber without complex separation steps, overcoming the difficulty of recovering traditional powder catalysts.

[0056] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a silver / bismuth oxychloride / bismuth oxide / carbon fiber composite photocatalyst, characterized by, The method comprises the following steps: A. mixing carbon fiber with bismuth nitrate solution to obtain bismuth oxide / carbon fiber through reaction; B. taking the bismuth oxide / carbon fiber obtained in step A and reacting with bismuth nitrate solution and cetyltrimethylammonium chloride solution to obtain bismuth oxychloride / bismuth oxide / carbon fiber; C. taking the bismuth oxychloride / bismuth oxide / carbon fiber obtained in step B and performing photoreduction in silver nitrate solution to obtain silver / bismuth oxychloride / bismuth oxide / carbon fiber flexible composite photocatalyst after washing and drying; The bismuth nitrate solution is bismuth nitrate / ethylene glycol solution with a concentration of 0.1-0.2 mol / L; In step A, anhydrous ethanol is further included, and the volume ratio of the bismuth nitrate / ethylene glycol solution to the anhydrous ethanol is 1:2; In step A, the reaction temperature is 160℃, and the reaction time is 300 min; In step B, the volume ratio of the bismuth nitrate solution to the cetyltrimethylammonium chloride solution is 1:3; The bismuth nitrate solution is bismuth nitrate / ethylene glycol solution with a concentration of 0.0618 mol / L; The cetyltrimethylammonium chloride solution is cetyltrimethylammonium chloride / ethanol solution with a concentration of 0.03514 mol / L.

2. The production method according to claim 1, characterized by, In step B, the reaction temperature is 160℃, and the reaction time is 240 min.

3. The preparation method according to claim 1, characterized in that, In step C, the photoreduction is performed under the irradiation of a xenon lamp with a power of 300 W.

4. The method of claim 1, wherein, In step C, the concentration of the silver nitrate solution is 0.05-0.2 mol / L, and the reaction time is 10-30 min.

Images