A Cu-Fe2O3 / h-C3N4 catalytic material, its preparation method and application

Abstract

The application belongs to the technical field of photo-sulfate advanced oxidation, and particularly relates to a Cu-Fe2O3 / h-C3N4 catalytic material and a preparation method and application thereof. The Cu-Fe2O3 / h-C3N4 catalytic material provided by the application has a hollow tubular structure, a high specific surface area, a short electron transmission path and a high light scattering utilization rate. In addition, the doping of Cu can not only improve the problem of easy polymerization of the ferric oxide, but also promote the cycle of trivalent Fe ions / divalent Fe ions and improve the catalytic degradation activity. Due to the difference in Fermi energy levels of different semiconductor materials, the hybridization of Cu and the ferric oxide is also beneficial to the effective separation of photo-generated electron-hole pairs in space, improves the light response range, and makes the catalytic material have high efficient catalytic degradation performance, and can efficiently remove organic dyes and antibiotic organic matters in water under ultraviolet light.

Description

Technical Field

[0001] This invention belongs to the field of photo-persulfate advanced oxidation technology, specifically relating to a Cu-Fe2O3 / h-C3N4 catalytic material, its preparation method, and its application. Background Technology

[0002] Methylene blue is a phenothiazine dye with a complex chemical structure. It is a deep blue powder, soluble in water, alcohols, and chloroform. Methylene blue has a wide range of applications, including industry, medicine, and agriculture. In industry, it is used for dyeing cotton, silk, and paper, as well as for coloring bamboo and wood and manufacturing inks. In medicine, methylene blue is used to treat bacterial dysentery, cancer, bacterial and viral infections, and central nervous system diseases. It is also commonly used in aquaculture to treat certain fish diseases. Therefore, efficiently and environmentally friendly degradation of methylene blue in water remains a pressing challenge. However, traditional water treatment processes are ineffective at removing methylene blue. Therefore, there is an urgent need to find efficient and low-cost technologies to eliminate methylene blue from aquatic environments.

[0003] In recent years, numerous studies have shown that photo-persulfate technology is a promising treatment technique that can convert organic pollutants into harmless substances under mild conditions. Many researchers have also attempted to develop various highly efficient photocatalysts to decompose methylene blue in water. Among the many reported photocatalytic materials, g-C3N4 has attracted considerable attention due to its suitable bandgap structure, simple synthesis method, good chemical stability, and inexpensive raw materials. However, the catalytic activity of g-C3N4 is limited by the easy recombination of photogenerated electron-hole pairs, its low specific surface area, and its limited photoresponse range. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a Cu-Fe2O3 / h-C3N4 catalytic material, its preparation method and application. The Cu-Fe2O3 / h-C3N4 catalytic material provided by this invention has excellent catalytic performance and excellent photocatalytic degradation effect on organic dyes and antibiotics.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The present invention provides a Cu-Fe2O3 / h-C3N4 catalytic material, comprising h-C3N4 having a hollow tubular structure and Cu and Fe2O3 supported on the surface and pore structure of the h-C3N4.

[0007] Preferably, the Cu loading in the Cu-Fe2O3 / h-C3N4 catalyst is 0.03–0.07 g / g, and the Fe2O3 loading is 0.4–0.9 g / g.

[0008] Preferably, the specific surface area of ​​the Cu-Fe2O3 / h-C3N4 catalyst is 60-75 m². 2 / g, with an average pore size of 11–14 nm.

[0009] This invention also provides a method for preparing the Cu-Fe2O3 / h-C3N4 catalytic material described in the above technical solution, comprising the following steps:

[0010] Melamine and urea were mixed and calcined under a nitrogen atmosphere to obtain h-C3N4 with a hollow tubular structure.

[0011] The hollow tubular structure h-C3N4, ferric chloride, copper chloride and a polar organic solvent are mixed, and the resulting mixture is mixed with an aqueous solution of ammonium bicarbonate to carry out a solvothermal reaction to obtain Cu-Fe2O3 / h-C3N4 catalytic material.

[0012] Preferably, the mass ratio of melamine to urea is 1:8 to 12.

[0013] Preferably, the calcination temperature is 200–550°C, and the holding time is 2–6 hours.

[0014] Preferably, the flow rate of the nitrogen gas is 50-60 mL / min.

[0015] Preferably, the temperature of the solvothermal reaction is 15–45°C, and the holding time is 4–8 h.

[0016] Preferably, the mass ratio of the hollow tubular structure h-C3N4, ferric chloride, and copper chloride is (5-20):(8-80):1.

[0017] This invention also provides the application of the Cu-Fe2O3 / h-C3N4 catalytic material described in the above technical solution or the Cu-Fe2O3 / h-C3N4 catalytic material prepared by the preparation method described in the above technical solution in the degradation of organic dyes and / or antibiotic organic compounds.

[0018] This invention provides a Cu-Fe2O3 / h-C3N4 catalytic material, comprising h-C3N4 with a hollow tubular structure and Cu and Fe2O3 supported on the surface and in the pore structure of the h-C3N4. Compared with other forms (nanoflakes, nanospheres, nanofibers, quantum dot spindles, etc.), the h-C3N4 in the Cu-Fe2O3 / h-C3N4 catalytic material provided by this invention has a hollow tubular structure, resulting in high specific surface area, short electron transport paths, and high light scattering efficiency. Furthermore, Cu doping not only improves the ease of Fe2O3 polymerization but also promotes Fe... 3+ / Fe 2+ The cycling process enhances the catalytic degradation activity. Due to the Fermi level differences among different semiconductor materials, the hybridization of Cu and Fe2O3 also facilitates the effective spatial separation of photogenerated electron-hole pairs, improving the light response range and giving it highly efficient photocatalytic degradation performance. It can efficiently remove organic dyes and antibiotics from water under ultraviolet light. The results of the examples show that the Cu-Fe2O3 / h-C3N4 catalytic material provided by this invention exhibits the best catalytic performance, achieving a 100% degradation rate for the phenothiazine dye methylene blue in 90 minutes. It also shows similar degradation effects for various dyes, such as cresol red (93%) and Sudan III (85%), and similar degradation effects for antibiotics such as sulfonamides (91%) and ciprofloxacin (86%). This provides a good material basis and technical support for the application of the photo-persulfate system in wastewater treatment. Attached Figure Description

[0019] Figure 1 The XRD patterns of Cu-Fe2O3 / h-C3N4 catalyst, h-C3N4, Fe2O3 / h-C3N4 catalyst and g-C3N4 prepared in Example 1 of this invention are shown.

[0020] Figure 2 SEM images of Cu-Fe2O3 / h-C3N4 catalyst, h-C3N4, Fe2O3 / h-C3N4 catalyst and g-C3N4 prepared in Example 1 of this invention; wherein (a) is g-C3N4, (b) is h-C3N4, (c) is Fe2O3 / h-C3N4, and (d) is Cu-Fe2O3 / h-C3N4;

[0021] Figure 3 This is a TEM image of the Cu-Fe2O3 / h-C3N4 catalytic material prepared in Example 1 of this invention;

[0022] Figure 4 The graph shows the degradation effect of different catalytic materials on methylene blue. Detailed Implementation

[0023] The present invention provides a Cu-Fe2O3 / h-C3N4 catalytic material, comprising h-C3N4 having a hollow tubular structure and Cu and Fe2O3 supported on the surface and pore structure of the h-C3N4.

[0024] The Cu-Fe2O3 / h-C3N4 catalytic material provided by this invention comprises h-C3N4 with a hollow tubular structure. In this invention, the specific surface area of ​​the h-C3N4 is preferably 60–70 m². 2 / g, more preferably 63-68m 2 / g, with an average pore size preferably of 10-12 nm, more preferably 11 nm.

[0025] The Cu-Fe2O3 / h-C3N4 catalytic material provided by this invention comprises Cu and Fe2O3 supported on the surface and pore structure of the h-C3N4 catalyst. In this invention, the Cu loading in the Cu-Fe2O3 / h-C3N4 catalytic material is preferably 0.03–0.07 g / g, more preferably 0.025–0.038 g / g, and the Fe2O3 loading is preferably 0.4–0.9 g / g, more preferably 0.5–0.7 g / g.

[0026] In this invention, the specific surface area of ​​the Cu-Fe2O3 / h-C3N4 catalyst is preferably 60-75 m². 2 / g, more preferably 62–71.05m 2 / g, with an average pore size preferably of 11-14 nm, more preferably 11.5-13.32 nm.

[0027] Compared with other forms (nanoflakes, nanospheres, nanofibers, quantum dot spindles, etc.), the Cu-Fe2O3 / h-C3N4 catalytic material provided by this invention has a hollow tubular structure in h-C3N4, resulting in high specific surface area, short electron transport paths, and high light scattering efficiency. Furthermore, Cu doping not only improves the ease of Fe2O3 polymerization but also promotes Fe... 3+ / Fe 2+ The cycling process enhances the catalytic degradation activity. Due to the Fermi level differences of different semiconductor materials, the hybridization of Cu and Fe2O3 also facilitates the effective spatial separation of photogenerated electron-hole pairs, improving the light response range and giving it highly efficient photocatalytic degradation performance. It can efficiently remove organic dyes and antibiotics from water under ultraviolet light.

[0028] This invention also provides a method for preparing the Cu-Fe2O3 / h-C3N4 catalytic material described in the above technical solution, comprising the following steps:

[0029] Melamine and urea were mixed and calcined under a nitrogen atmosphere to obtain h-C3N4 with a hollow tubular structure.

[0030] The hollow tubular structure h-C3N4, ferric chloride, copper chloride and a polar organic solvent are mixed, and the resulting mixture is mixed with an aqueous solution of ammonium bicarbonate to carry out a solvothermal reaction to obtain Cu-Fe2O3 / h-C3N4 catalytic material.

[0031] Unless otherwise specified, the present invention does not have special requirements on the source of the raw materials used in the preparation, and commercially available products well known to those skilled in the art can be used.

[0032] This invention involves mixing melamine and urea and calcining them under a nitrogen atmosphere to obtain h-C3N4 with a hollow tubular structure.

[0033] In this invention, the mass ratio of melamine to urea is preferably 1:8 to 12, and more preferably 1:9 to 10.

[0034] Before calcination, the present invention preferably pulverizes the mixture obtained by mixing melamine and urea to obtain powder; the pulverization is preferably grinding.

[0035] In this invention, the calcination temperature is preferably 200–550°C, more preferably 300–550°C, and the holding time is preferably 2–6 h, more preferably 3–4 h; the heating rate to the calcination temperature is preferably 2–3°C / min, more preferably 2.5°C / min; and the nitrogen flow rate is preferably 50–60 mL / min, more preferably 50–55 mL / min.

[0036] During the calcination process, the release of generated gases (such as ammonia) promotes the formation of hollow tubes. As the temperature rises and the calcination time increases, the surface of the hollow tubes gradually cracks, eventually yielding h-C3N4 with a hollow tubular structure.

[0037] After obtaining the hollow tubular structure h-C3N4, the present invention mixes the hollow tubular structure h-C3N4, ferric chloride, copper chloride and a polar organic solvent, and mixes the resulting mixture with an aqueous solution of ammonium bicarbonate to carry out a solvothermal reaction to obtain Cu-Fe2O3 / h-C3N4 catalytic material.

[0038] In this invention, the polar organic solvent is preferably anhydrous ethanol; the ratio of the amount of h-C3N4 with a hollow tubular structure to the polar organic solvent is preferably (8-12) g:1 L, more preferably (9-10) g:1 L.

[0039] In this invention, the mass ratio of the hollow tubular structure h-C3N4, ferric chloride, and copper chloride is preferably (5-20):(8-80):1, more preferably (10-15):(16-40):1; the mass concentration of the aqueous solution of ammonium bicarbonate is preferably 150-250 g / L, more preferably 155-240 g / L; and the mass ratio of the total amount of ferric chloride and copper chloride to the amount of ammonium bicarbonate is preferably 1-4:5, more preferably 1-2:5.

[0040] In this invention, the preferred method for mixing the hollow tubular structure h-C3N4, ferric chloride, copper chloride, and polar organic solvent is as follows: h-C3N4 with a hollow tubular structure and the polar organic solvent are mixed and ultrasonicated to obtain an h-C3N4 suspension; ferric chloride and copper chloride are then added to the h-C3N4 suspension to obtain a mixed solution. In this invention, the ultrasonic power is preferably 300–800 W, more preferably 400–500 W; the ultrasonic time is preferably 15–60 min, more preferably 30–50 min.

[0041] In this invention, the temperature of the solvothermal reaction is preferably 15-45°C, more preferably 25-40°C, and the holding time is preferably 4-8h, more preferably 5-6h; the solvothermal reaction is preferably carried out under stirring conditions; the stirring rate is preferably 500-1000rpm, more preferably 600-800rpm.

[0042] After the solvothermal reaction is completed, the present invention preferably performs solid-liquid separation, washing and drying on the solvothermal reaction products in sequence to obtain Cu-Fe2O3 / h-C3N4 catalytic material.

[0043] In this invention, the solid-liquid separation is preferably filtration; the washing agent is preferably ethanol; the number of washing cycles is preferably 2-6 times, more preferably 3-5 times; the drying temperature is preferably 50-80°C, more preferably 55-60°C; and the drying time is preferably 8-24 hours, more preferably 12-16 hours. This invention removes impurities and intermediates from the product through washing. The ethanol used in this invention has low toxicity, is readily available, and significantly improves the purity of the product.

[0044] This invention also provides the application of the Cu-Fe2O3 / h-C3N4 catalytic material described in the above technical solution or the Cu-Fe2O3 / h-C3N4 catalytic material prepared by the preparation method described in the above technical solution in the degradation of organic dyes and / or antibiotic organic compounds.

[0045] In this invention, the organic dye preferably includes one or more of methylene blue, cresol red and Sudan III, more preferably methylene blue; the antibiotic organic compound preferably includes sulfonamide and / or ciprofloxacin, more preferably sulfonamide.

[0046] The present invention does not impose any particular limitation on the application of the Cu-Fe2O3 / h-C3N4 catalytic material in the degradation of organic dyes and / or antibiotics; any application method known in the art may be used.

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] Melamine and urea in a mass ratio of 1:9 were ground into powder. 13g of the powder was taken each time and calcined in a quartz tube furnace under a nitrogen atmosphere at a heating rate of 3℃ / min to 550℃ for 4h. The nitrogen flow rate was 55mL / min, and hollow tubular h-C3N4 was obtained.

[0050] 500 mg of hollow tubular h-C3N4 from Example 1 was added to 50 mL of anhydrous ethanol and sonicated at 500 W for 30 min to obtain an h-C3N4 suspension. Then, 3 mmol FeCl3·6H2O and 0.3 mmol CuCl2·2H2O were added to the h-C3N4 suspension and mixed to obtain a mixed solution.

[0051] 711.5 mg of NH4HCO3 was fully dissolved in 3 mL of distilled water. The resulting aqueous solution of ammonium bicarbonate was quickly poured into the above mixture. The solution reacted violently, rapidly changing from green to a yellow suspension. The solution was stirred at 800 rpm for 6 h at 25 °C for a solvothermal reaction. The product was filtered, and the solid was washed three times with ethanol. Finally, it was dried in an oven at 60 °C for 12 h to obtain the Cu-Fe2O3 / h-C3N4 catalyst.

[0052] Example 2

[0053] 500 mg of hollow tubular h-C3N4 from Example 1 was added to 50 mL of anhydrous ethanol and sonicated at 500 W for 30 min to obtain an h-C3N4 suspension. Then, 3 mmol FeCl3·6H2O and 0.3 mmol CuCl2·2H2O were added to the h-C3N4 suspension and mixed to obtain a mixed solution.

[0054] 474.3 mg of NH4HCO3 was fully dissolved in 3 mL of distilled water. The resulting aqueous solution of ammonium bicarbonate was quickly poured into the above mixture. The solution reacted violently, rapidly changing from green to a yellow suspension. The solution was stirred at 800 rpm for 6 h at 25 °C for a solvothermal reaction. The product was filtered, and the resulting solid was washed three times with ethanol. Finally, it was dried in an oven at 60 °C for 12 h to obtain the Cu-Fe2O3 / h-C3N4 catalyst.

[0055] Comparative Example 1

[0056] The difference from Example 1 is that copper chloride was not added, but the rest of the contents are the same as in Example 1, and Fe2O3 / h-C3N4 catalyst material was prepared.

[0057] Application Example 1

[0058] Prepare a 20 mg / L methylene blue aqueous solution using deionized water. Take 40 mL of the solution and add it to a quartz tube for photoreaction. Then add 20 mg of the Cu-Fe2O3 / h-C3N4 catalyst prepared in Example 1, 150 μL of 0.5 mol / L persulfate (PMS), and a magnetic stir bar. Place the tube into the photoreaction apparatus, turn on the cooling water to control the reaction temperature at 25°C, turn on the power, and turn on the stirring button. First, perform a dark reaction to reach adsorption-desorption equilibrium, then turn on the lamp (500W xenon lamp) to carry out degradation.

[0059] Application Example 2

[0060] The difference from Application Example 1 is that the Cu-Fe2O3 / h-C3N4 catalyst prepared in Example 1 is replaced with the Fe2O3 / h-C3N4 catalyst of Comparative Example 1, and the rest is the same as Application Example 1.

[0061] Application Example 3

[0062] The difference from Application Example 1 is that the Cu-Fe2O3 / h-C3N4 catalyst material prepared in Example 1 is replaced with h-C3N4 prepared in Example 1, and the rest is the same as Application Example 1.

[0063] Application Example 4

[0064] The difference from Application Example 1 is that the Cu-Fe2O3 / h-C3N4 catalyst prepared in Example 1 is replaced with g-C3N4, and the rest is the same as Application Example 1.

[0065] Performance testing

[0066] (1) The Cu-Fe2O3 / h-C3N4 catalyst, h-C3N4, Fe2O3 / h-C3N4 catalyst of Comparative Example 1, and g-C3N4 prepared in Example 1 of this invention were subjected to phase analysis by XRD. The results are as follows: Figure 1 As shown.

[0067] Depend on Figure 1 The XRD characterization results show that the hollow tubular h-C3N4 has poorer crystallinity than the bulk g-C3N4. Furthermore, a new small peak appears with the loading of Fe2O3 and Cu, which proves the successful loading of Fe2O3 and Cu.

[0068] (2) The morphology of the Cu-Fe2O3 / h-C3N4 catalyst, h-C3N4, Fe2O3 / h-C3N4 catalyst and g-C3N4 prepared in Example 1 of this invention were characterized by SEM, and the results are as follows: Figure 2 As shown; where (a) is g-C3N4, (b) is h-C3N4, (c) is Fe2O3 / h-C3N4, and (d) is Cu-Fe2O3 / h-C3N4.

[0069] Depend on Figure 2 It can be seen that the outer wall of the simple hollow tubular h-C3N4 has many holes. With the loading of Fe2O3 and Cu, the outer wall of the tube gradually becomes complete, and the precipitation of particulate matter can be clearly observed.

[0070] (3) The Cu-Fe2O3 / h-C3N4 catalytic material prepared in Example 1 of this invention was characterized by TEM, and the results are as follows: Figure 3 As shown.

[0071] Depend on Figure 3 It was discovered that the tube wall of h-C3N4 is composed of multiple thin films with extremely small particles distributed on the surface. This also confirms that the present invention obtains a high-performance photocatalytic material by controlling the loading of Cu-Fe2O3.

[0072] (4) The degradation effects of different catalytic materials on methylene blue were tested. The specific experimental procedure is shown in Application Example 1. A 500W mercury lamp was used as the light source. The photo-persulfate system was used to degrade methylene blue in an XPA-7 photoreactor. Circulating cooling water was used to maintain the reaction system temperature at 25℃. The catalyst dosage was 0.5 g / L, the methylene blue concentration was 20 mg / L, and the PMS concentration was 2.5 mmol / L. Samples were taken at set time intervals, and the concentration of remaining methylene blue was measured. The experiment included two cases: with and without PMS. The results are shown below. Figure 4 As shown, (a) represents dark-adsorbed methylene blue under no-light conditions, and (b) represents photodegraded methylene blue using different materials and systems.

[0073] like Figure 4 As shown in the figure, all materials were basically saturated with adsorption within 30 minutes, and the adsorption amount of pollutants increased significantly in the PMS system. In the photo-persulfate system, the Cu-Fe2O3 / h-C3N4 composite material prepared in Example 1 showed the best performance, completely degrading it within 90 minutes. This indicates that when an appropriate concentration of Cu-Fe2O3 is loaded, the morphology of the prepared material exhibits the best PMS synergistic effect, resulting in excellent catalytic degradation performance of methylene blue.

[0074] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. The application of Cu-Fe2O3 / h-C3N4 catalytic material in the degradation of organic dyes and / or antibiotic-like organic compounds, characterized in that, The Cu-Fe2O3 / h-C3N4 catalytic material comprises h-C3N4 with a hollow tubular structure and Cu and Fe2O3 supported on the surface and pore structure of the h-C3N4; the Cu loading in the Cu-Fe2O3 / h-C3N4 catalytic material is 0.03~0.07 g / g, and the Fe2O3 loading is 0.4~0.9 g / g; the specific surface area of ​​the Cu-Fe2O3 / h-C3N4 catalytic material is 60~75 m². 2 / g, with an average pore size of 11~14nm; The preparation method of the Cu-Fe2O3 / h-C3N4 catalytic material includes the following steps: Melamine and urea were mixed and calcined under a nitrogen atmosphere to obtain h-C3N4 with a hollow tubular structure. The hollow tubular structure of h-C3N4, ferric chloride, copper chloride and polar organic solvent are mixed, and the resulting mixture is mixed with an aqueous solution of ammonium bicarbonate to carry out a solvothermal reaction to obtain Cu-Fe2O3 / h-C3N4 catalytic material. The organic dyes include one or more of methylene blue, cresol red, and Sudan III; the antibiotic organic compounds include sulfonamides and / or ciprofloxacin. The degradation was carried out in a photo-persulfate system.

2. The application according to claim 1, characterized in that, The mass ratio of melamine to urea is 1:8~12.

3. The application according to claim 1, characterized in that, The calcination temperature is 200~550℃, and the holding time is 2~6h.

4. The application according to claim 1, characterized in that, The flow rate of the nitrogen gas is 50~60 mL / min.

5. The application according to claim 1, characterized in that, The temperature of the solvothermal reaction is 15~45℃, and the holding time is 4~8h.

6. The application according to claim 1, characterized in that, The mass ratio of the hollow tubular structure h-C3N4, ferric chloride, and copper chloride is (5~20):(8~80):1.

Images