A Co-doped FeWO4 / amorphous BiPO4 composite material, its preparation method, and its application in the degradation of methylene blue in water.
By preparing Co-doped FeWO4/amorphous BiPO4 composite materials, and utilizing cobalt doping modification and heterojunction structure, the problems of low efficiency and poor stability in the treatment of methylene blue dye wastewater in the prior art were solved, and a highly efficient and stable photocatalytic degradation effect was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIAONING UNIVERSITY
- Filing Date
- 2026-06-05
- Publication Date
- 2026-07-03
AI Technical Summary
Existing technologies for treating methylene blue dye wastewater suffer from problems such as insufficient visible light utilization, severe recombination of photogenerated carriers, high charge transport resistance, and poor material cycling stability, making it difficult to achieve efficient and stable degradation results.
Co-doped FeWO4/amorphous BiPO4 composite materials were prepared. By modifying the material with cobalt doping and constructing a heterojunction structure, the visible light response, charge separation efficiency and surface catalytic activity of the material were improved. Combined with the metal-semiconductor synergistic effect, the electronic structure and interfacial charge transfer were optimized.
It achieves rapid and efficient degradation of methylene blue dye, significantly improves the cycling stability and degradation efficiency of the material, with a degradation rate of up to 98%, and the efficiency decay is less than 5% after multiple uses.
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Figure CN122321905A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic matter degradation applications, specifically relating to a Co-doped FeWO4 / amorphous BiPO4 composite material, its preparation method, and its application in the degradation of methylene blue in water. Background Technology
[0002] With the rapid development of industries such as printing and dyeing, textiles, and chemicals, large amounts of organic wastewater containing dyes are discharged during production processes, leading to increasingly severe organic pollution problems in water bodies. Methylene blue (MB), a typical cationic aromatic dye, is widely used in printing and dyeing, papermaking, and bio-dyeing. This dye has a stable molecular structure, a complex aromatic ring conjugated system, and extremely poor biodegradability, making it difficult to completely remove using conventional physical adsorption and biological treatment processes. Furthermore, high-concentration MB wastewater is highly chromatic and toxic; once it enters water bodies, it hinders photosynthesis in aquatic organisms, disrupts the ecological balance of aquatic bodies, and, through long-term accumulation, harms human health via the food chain. Therefore, developing efficient, green, and recyclable MB wastewater treatment technologies is of significant practical importance. Photocatalytic advanced oxidation technology, with its advantages of solar energy drive, mild reaction conditions, no secondary pollution, and deep mineralization of organic pollutants, has become one of the mainstream technologies for treating recalcitrant dye wastewater. Developing highly active, broad-spectrum-response, and structurally stable semiconductor photocatalytic materials is the core of this technology's practical application. There are still obvious shortcomings in the current application of methylene blue (MB) degradation: First, the utilization rate of visible light is insufficient and the light energy conversion efficiency is low; second, the recombination of photogenerated charge carriers is serious and the amount of oxidative free radicals generated is low; third, the material interface is loose and the charge transport resistance is high; fourth, the cycle stability is poor and the MB degradation activity is greatly reduced after multiple reuses, which is difficult to meet the actual wastewater treatment needs.
[0003] This invention designs and prepares a Co-doped modified iron tungstate substrate, constructs a heterojunction structure with bismuth phosphate, and utilizes the multiple synergistic effects of cobalt doping modification, metal-semiconductor synergy, and heterojunction charge separation mechanism to significantly improve the visible light response, charge separation efficiency, and surface catalytic activity of the material, achieving rapid and efficient degradation of methylene blue dye. At the same time, it significantly improves the material's cycle stability, providing a novel and efficient catalytic material and feasible preparation process for the green treatment of methylene blue pollutants in dyeing and printing wastewater. Summary of the Invention
[0004] To address the current research shortcomings, this invention provides a method for preparing Co-doped FeWO4 / amorphous BiPO4 composite materials, comprising the following steps.
[0005] Tungstic acid was added to deionized water and stirred thoroughly; ferric nitrate nonahydrate and cobalt nitrate hexahydrate were added and stirred; bismuth nitrate pentahydrate was added and stirred; phosphoric acid was added and stirred to obtain a mixed solution; the pH of the mixed solution was adjusted using sodium hydroxide solution, and the solution was transferred to a reaction vessel for hydrothermal reaction. After the reaction was completed, the solution was cooled, washed, and dried to obtain a powder; the obtained powder was added to a muffle furnace for calcination and cooled to obtain the target product.
[0006] The above-mentioned preparation method of Co-doped FeWO4 / amorphous BiPO4 composite material uses a molar ratio of tungstic acid: ferric nitrate nonahydrate: cobalt nitrate hexahydrate: bismuth nitrate pentahydrate: phosphoric acid = 10:1:10:11:10.
[0007] The preparation method of the above-mentioned Co-doped FeWO4 / amorphous BiPO4 composite material, wherein the hydrothermal reaction conditions are 160~200℃ for 10~14 h.
[0008] In the preparation method of the above-mentioned Co-doped FeWO4 / amorphous BiPO4 composite material, the pH value adjustment range is 4~5.
[0009] The preparation method of the above-mentioned Co-doped FeWO4 / amorphous BiPO4 composite material, wherein the calcination conditions are calcination at 200~400℃ for 3~5 h.
[0010] A Co-doped FeWO4 / amorphous BiPO4 composite material prepared according to the above preparation method.
[0011] Application of the above-mentioned Co-doped FeWO4 / amorphous BiPO4 composite material in the degradation of methylene blue in water.
[0012] The application of the above-mentioned Co-doped FeWO4 / amorphous BiPO4 composite material in the degradation of methylene blue in water is as follows: Under xenon lamp irradiation, the Co-doped FeWO4 / amorphous BiPO4 composite material is mixed with a methylene blue solution, and hydrogen peroxide solution is added to degrade the methylene blue.
[0013] The above-mentioned Co-doped FeWO4 / amorphous BiPO4 composite material was used in the degradation of methylene blue in water, with a methylene blue solution concentration of 9 × 10⁻⁶. -6 ~2×10 -5 The concentration of hydrogen peroxide solution was 10 mol / L. The ratio of Co-doped FeWO4 / amorphous BiPO4 composite material to methylene blue solution to hydrogen peroxide solution was 20 mg: 20 mL: 0.2 mL.
[0014] The beneficial effects of the present invention.
[0015] 1. The Co-doped FeWO4 / amorphous BiPO4 composite material prepared by this invention can achieve high-efficiency degradation of methylene blue dye molecules in water.
[0016] 2. This invention designs and prepares a Co-doped modified iron tungstate substrate, constructs a heterojunction structure with bismuth phosphate, and utilizes the multiple synergistic effects of cobalt doping modification, metal-semiconductor synergy, and heterojunction charge separation mechanism to significantly improve the visible light response, charge separation efficiency, and surface catalytic activity of the material, thereby achieving rapid and efficient degradation of methylene blue dye.
[0017] 3. This invention optimizes the electronic structure of FeWO4 by cobalt doping, and combines the high adsorption performance and interfacial charge transfer capability of amorphous BiPO4 to construct a synergistically enhanced photo-assisted Fenton catalytic system. This system not only improves the material's performance but also significantly enhances its cycling stability and greatly shortens the degradation time. Attached Figure Description
[0018] Figure 1 This is the XRD pattern of the Co-doped FeWO4 / amorphous BiPO4 composite material prepared in Example 1.
[0019] Figure 2 These are the UV absorption peaks of the mixed solutions in Example 1, which were stirred for 30 minutes under light-protected conditions and stirred for different times under xenon lamp irradiation.
[0020] Figure 3 The graph shows the relative absorbance curves of the mixed solutions in Example 1, which were stirred for 30 minutes under light-protected conditions and stirred for different times under xenon lamp irradiation.
[0021] Figure 4 This is a bar chart showing the repeated degradation efficiency of the Co-doped FeWO4 / amorphous BiPO4 composite material. Detailed Implementation
[0022] To better understand the technical solution of the present invention, specific embodiments are provided for further detailed description, but the solution is not limited thereto.
[0023] Example 1: Preparation of Co-doped FeWO4 / amorphous BiPO4 composite material.
[0024] The specific preparation method is as follows.
[0025] 1) Add 60mL of deionized water to a beaker, turn on the magnetic stirrer, add 0.50g of tungstic acid, and stir for 30 minutes to fully disperse it.
[0026] 2) Add 0.81g of ferric nitrate nonahydrate and 0.058g of cobalt nitrate hexahydrate, and continue stirring for 20 minutes.
[0027] 3) Add 0.97g of bismuth nitrate pentahydrate and stir for 15 minutes.
[0028] 4) Slowly add 0.14 mL of 85% phosphoric acid using a pipette, and continue stirring for 15 minutes after the addition is complete.
[0029] 5) Slowly adjust the pH to 4.0 using 0.5M NaOH.
[0030] 6) Transfer the suspension to a 100mL hydrothermal reactor, place it in an oven, and hydrothermally react at 180℃ for 12 hours. Allow it to cool naturally to room temperature, centrifuge to collect the precipitate, wash it three times with deionized water and once with anhydrous ethanol, and vacuum dry it at 60℃ for 12 hours to obtain the powder sample.
[0031] 7) Add the above powder to a muffle furnace and calcine at 300°C for 4 hours. Cool to obtain the target product.
[0032] XRD tests were performed on the Co-doped FeWO4 / amorphous BiPO4 prepared in Example 1. The test results are as follows: Figure 1 As shown, the peak values in the experimental sample correspond very well to the characteristic peaks of FeWO4. Due to the expansion of the unit cell caused by Co doping, the strongest characteristic peak of FeWO4 at 30.3° shifted slightly to 29.8°, and the other peak values also shifted slightly. There are no characteristic peaks of BiPO4 in the figure, which also indicates that BiPO4 does exist in the sample in an amorphous form, indicating the successful preparation of Co-doped FeWO4 / amorphous BiPO4.
[0033] Example 2: Application of Co-doped FeWO4 / amorphous BiPO4 composite material in methylene blue.
[0034] 20 mg of the Co-doped FeWO4 / amorphous BiPO4 mixture prepared in Example 1 was added to 20 ml of a 10% concentration. -5 Add 0.2 mL of H2O2 to the MB solution of M, and irradiate it under a xenon lamp for different times for later use.
[0035] Comparative Example 1.
[0036] 20 mg of the Co-doped FeWO4 / amorphous BiPO4 mixture prepared in Example 1 was added to 20 ml of a 10% concentration. -5 In the MB solution of M, stir for 30 minutes under light-protected conditions, and set aside for later use.
[0037] The mixed solutions obtained in Comparative Example 1 and different mixed solutions obtained in Example 2 were detected using ultraviolet-visible molecular absorption spectroscopy. Figure 2As shown, the Co-doped FeWO4 / amorphous BiPO4 composite material prepared in Example 1 successfully and gradually degraded the dye molecule methylene blue using hydrogen peroxide under photo-assisted degradation, and reached stability after 20 minutes of photo-assisted degradation, with a degradation rate of about 98%. Figure 3 The relationship between absorbance and time can be observed in the figure. It can be seen from the figure that stirring under dark conditions without hydrogen peroxide has very little effect on the degradation of methylene blue, indicating that the synthesized composite material has no adsorption effect.
[0038] Example 3: Repeatability experiment of degradation of methylene blue by Co-doped FeWO4 / amorphous BiPO4 composite material.
[0039] The suspension after degradation in Example 2 was transferred to a centrifuge tube and centrifuged at 8000 rpm for 10 min. The supernatant was collected, washed three times with ethanol-deionized water-ethanol, and dried at 60°C. The steps of Example 2 were repeated 5 times for later use.
[0040] The results of Example 3 are as follows Figure 4 As shown in the figure, the degradation efficiency remained as high as 93% after 5 experiments, only about 5% lower than the first time, with a standard deviation of only 1.90%, far less than 5%. This indicates that the Co-doped FeWO4 / amorphous BiPO4 composite material exhibits excellent stability, repeatability, and high efficiency in degrading methylene blue. Therefore, the Co-doped FeWO4 / amorphous BiPO4 composite material prepared in Example 1 can effectively degrade the toxic dye methylene blue in water.
Claims
1. A preparation method of Co-doped FeWO4 / amorphous BiPO4 composite material, characterized in that, Includes the following steps: Add tungstic acid to deionized water and stir thoroughly; add ferric nitrate nonahydrate and cobalt nitrate hexahydrate, and stir. Add bismuth nitrate pentahydrate and stir; Phosphoric acid was added and stirred to obtain a mixed solution. The pH of the mixed solution was adjusted using sodium hydroxide solution, and the solution was transferred to a reaction vessel for hydrothermal reaction. After the reaction was completed, the solution was cooled, washed, and dried to obtain a powder. The powder was then added to a muffle furnace for calcination and cooled to obtain the target product.
2. The method for preparing a Co-doped FeWO4 / amorphous BiPO4 composite material according to claim 1, characterized in that, The molar ratio of tungstic acid: ferric nitrate nonahydrate: cobalt nitrate hexahydrate: bismuth nitrate pentahydrate: phosphoric acid is 10:1:10:11:
10.
3. The method for preparing a Co-doped FeWO4 / amorphous BiPO4 composite material according to claim 1, characterized in that, The hydrothermal reaction is carried out at 160-200℃ for 10-14 h.
4. The method for preparing a Co-doped FeWO4 / amorphous BiPO4 composite material according to claim 1, characterized in that, The pH adjustment range is 4 to 5.
5. The method for preparing a Co-doped FeWO4 / amorphous BiPO4 composite material according to claim 1, characterized in that, The calcination conditions are calcination at 200~400℃ for 3~5 h.
6. A Co-doped FeWO4 / amorphous BiPO4 composite material prepared according to the preparation method of any one of claims 1-5.
7. The application of the Co-doped FeWO4 / amorphous BiPO4 composite material according to claim 6 in the degradation of methylene blue in water.
8. The application of the Co-doped FeWO4 / amorphous BiPO4 composite material according to claim 7 in the degradation of methylene blue in water, characterized in that, The method is as follows: Under xenon lamp irradiation, the Co-doped FeWO4 / amorphous BiPO4 composite material is mixed with methylene blue solution, and hydrogen peroxide solution is added to degrade the methylene blue.
9. The application of the Co-doped FeWO4 / amorphous BiPO4 composite material according to claim 8 in the degradation of methylene blue in water, characterized in that, The concentration of methylene blue solution was 9 x 10 -6 ~2 x 10 -5 mol / L, the concentration of hydrogen peroxide solution was 10 mol / L, and the Co-doped FeWO4 / amorphous BiPO4 composite: methylene blue solution: hydrogen peroxide solution = 20 mg: 20 mL: 0.2 mL.