A wide-spectrum, low-cost photocatalytic degradation material and a preparation method thereof

Abstract

The application discloses a preparation method of a wide-spectrum and low-cost photocatalytic degradation material, which comprises the following steps: adding hydrofluoric acid into acetic acid solution to obtain a first solution, adding alkyl titanate and a doping substance into the first solution, stirring uniformly to obtain a first mixture, placing the first mixture in a reaction kettle, and reacting at 150-300 DEG C for 12-30 hours; after the reaction is completed, cooling, collecting, washing, drying and calcining the precipitate to obtain the wide-spectrum and low-cost photocatalytic degradation material. By means of doping black TiO2, alpha-Fe2O3 and gamma-Fe2O3, the band gap of the composite TiO2 material is reduced, the catalytic material has the advantages of responding to a wide spectrum, good catalytic performance, low price and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inorganic chemistry, and particularly relates to a wide-spectrum and low-cost photocatalytic degradation material and a preparation method thereof. BACKGROUND

[0002] Photocatalysis is a commonly used method in advanced oxidation technology (AOP), and has the characteristics of wide application range, high degradation efficiency and simple operation, and is an "environment-friendly" green sewage treatment process. The photocatalytic oxidation process uses active groups such as hydroxyl radicals (·OH) to oxidize organic pollutants in water bodies.

[0003] The photocatalytic oxidation process cannot be carried out without the addition of photocatalytic materials, and the photocatalytic degradation materials mainly include TiO2, ZnO, SnO2, bismuth vanadate, bismuth halide and the like. Among them, the TiO2-based photocatalytic degradation material is widely used in the degradation of organic matter due to its low price, good catalytic performance and stable structure. However, due to the large band gap of TiO2 material, it cannot effectively respond to visible light, and cannot fully utilize natural light to carry out photocatalytic degradation of potassium salt flotation reagents. SUMMARY

[0004] The purpose of the present application is to overcome the problems of incomplete degradation, high cost, the need to invest in soluble chemical reagents and difficulty in industrialization in the current treatment of potassium salt flotation process collector, and to provide a preparation method of a wide-spectrum and low-cost photocatalytic degradation material. TiO2 is used as the matrix of the photocatalyst, and substances with small band gap such as black titanium dioxide, alpha-iron oxide and gamma-iron oxide are doped to reduce the band gap of the composite material, so that the material can respond to visible light, and the purpose of improving the photocatalytic degradation of potassium salt flotation reagents octadecylamine and / or dodecylmorpholine is achieved. The catalytic material has the advantages of wide-spectrum response, good catalytic performance and low price.

[0005] The present application is realized by the following technical scheme:

[0006] A preparation method of a wide-spectrum and low-cost photocatalytic degradation material, comprising:

[0007] Hydrofluoric acid is added to an acetic acid solution to obtain a first solution, titanium alkyl ester and doping substances are added to the first solution, and a first mixture is obtained after stirring uniformly. The first mixture is transferred to a reaction kettle, and reacted at 150-300 DEG C for 12-30 h. After the reaction is completed, the precipitate is collected and washed and dried to obtain the wide-spectrum and low-cost photocatalytic degradation material;

[0008] The molar fraction of acetic acid in the first solution is 70-90%;

[0009] The molar fraction of hydrofluoric acid in the first solution is 1.0-8.0%.

[0010] The doping substance is one or more of black titanium dioxide, alpha-iron oxide, and gamma-iron oxide (the band gap of the above materials is low, and the purpose of doping is to reduce the band gap of the titanium dioxide material, so that the composite material responds to a wider range of light, and the response spectrum range is extended to the visible light region);

[0011] The addition amount of the alkyl titanate is 0.5% to 4.5% of the molar fraction of the addition of acetic acid (to ensure that the alkyl titanate can be fully hydrolyzed to determine the addition amount);

[0012] The addition amount of the doping substance is 0.075wt% to 7.5wt% of the mass of the alkyl titanate (with the alkyl titanate as the titanium source, the hydrolysis degree is controlled in the range of 60% to 70%, and the mass of the doping substance in the final obtained photocatalytic degradation material accounts for 0.5% to 50% of the total mass of the photocatalytic degradation material);

[0013] In the above technical solution, the alkyl titanate is one or more of tetraethyl titanate, tetrabutyl titanate, and tetraisopropyl titanate.

[0014] In the above technical solution, when the doping substance is alpha-iron oxide and / or gamma-iron oxide, it can be synthesized in the laboratory or purchased as a commercial product, and is preferably purchased. The alkyl titanate and the doping substance are added to the first solution, and the pH of the first solution is ensured to be 3.0 to 4.0, and the addition amount of the doping substance is 0.075wt% to 7.5wt% of the mass of the alkyl titanate.

[0015] In the above technical solution, the dried precipitate is calcined at 400°C to 600°C for 2 to 10 hours to obtain the wide-spectrum, low-cost photocatalytic degradation material;

[0016] In the above technical solution, the black titanium dioxide is prepared by the following method:

[0017] Sodium tetrahydroborate and titanium dioxide are mixed in a mass ratio of 1:1 to 1:5, ground and stirred uniformly, placed in a tube furnace, and reduced by high-temperature reduction, the reduction temperature is 350°C to 500°C, the reduction time is 1 to 3 hours, the reduction protection gas can be nitrogen, helium, argon, and is preferably argon. The reduced product is washed with deionized water for 2 to 4 times, dried, and the black titanium dioxide is obtained.

[0018] In the above technical solution, the titanium dioxide is prepared by the following method:

[0019] adding hydrofluoric acid into acetic acid solution to obtain a first solution, adding alkyl titanate into the first solution, stirring to obtain a second mixture, sealing the second mixture in a reaction kettle, and reacting at 150-300 DEG C for 12-30 hours, cooling after the reaction, collecting and washing the precipitate, drying, and calcining the dried precipitate at 400-600 DEG C for 2-10 hours to obtain the titanium dioxide.

[0020] The amount of the added tetrabutyl titanate is 0.5-4.5% of the molar fraction of the added acetic acid.

[0021] In the technical solution, the tetrabutyl titanate is added slowly, preferably dropwise.

[0022] In the technical solution, the particle size of the wide-spectrum and low-cost photocatalytic degradation material is adjusted by adjusting the content of the hydrofluoric acid in the first solution.

[0023] The catalyst prepared by the preparation method of the wide-spectrum and low-cost photocatalytic degradation material.

[0024] The application of the catalyst prepared by the preparation method of the wide-spectrum and low-cost photocatalytic degradation material in degrading potassium salt flotation collector.

[0025] In the technical solution, the potassium salt flotation collector is octadecylamine and / or dodecylmorpholine.

[0026] The advantages and beneficial effects of the application are as follows:

[0027] 1. The synthesized photocatalyst has stable properties because it is based on titanium dioxide, and can be applied to solutions with different pH ranges, is resistant to acid and alkali, and is not decomposed, and can be separated from the system by filtration and recycled.

[0028] 2. By doping substances with small band gap, the band gap of the composite photocatalyst is reduced, the wavelength range of the response light is increased, the synthesized photocatalyst can respond to visible light to some extent, and the photocatalytic degradation efficiency of the photocatalyst on the potassium salt flotation reagent is improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The degradation rates of the anatase titanium dioxide prepared in Comparative Example 1 on octadecylamine and dodecylmorpholine at different times.

[0030] Fig. 2 is an SEM image of the synthesized anatase titanium dioxide in Comparative Example 2 by adding different volumes of hydrofluoric acid.

[0031] Figure 3is the SEM image of the composite photocatalytic material product with 5% of the mass ratio of black titanium dioxide prepared in Example 1.

[0032] Figure 4 is the degradation rate of octadecylamine and dodecylmorpholine by the 5wt% black titanium dioxide doped anatase titanium dioxide composite material prepared in Example 1 at different times.

[0033] Figure 5 is the degradation rate of octadecylamine and dodecylmorpholine by the 5wt% black titanium dioxide + 5wt% α-Fe2O3 doped anatase titanium dioxide composite material prepared in Example 2 at different times.

[0034] For those of ordinary skill in the art, other related drawings can be obtained according to the above drawings without creative labor. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical scheme of the present application, the technical scheme of the present application will be further described below in combination with specific embodiments.

[0036] Comparative Example 1 (without doping)

[0037] 1.1 An anatase titanium dioxide photocatalytic material is prepared by the following method:

[0038] Step 1, add 1.95 mL of deionized water and 55.8 mL of glacial acetic acid into the polytetrafluoroethylene liner, add 0.7 mL of 40wt% concentrated hydrofluoric acid solution, and then add 20.0 mL of tetrabutyl titanate into the solution drop by drop while stirring, and continue to stir for 30 min;

[0039] Step 2, place the liner in a reaction kettle and place it in a 180℃ oven for 24h. After the reaction kettle is naturally cooled to room temperature, the collected precipitate is washed with anhydrous ethanol and deionized water for 3 times respectively;

[0040] Step 3, dry the precipitate in a 60℃ oven for 6h, and then calcine the sample in a muffle furnace at 400℃ for 2h to remove organic volatile impurities. The undoped anatase titanium dioxide photocatalytic material is obtained.

[0041] 1.2 Octadecylamine degradation experiment

[0042] A solution of 100 mg / L octadecylamine + 1 g / L NaCl was placed in a photodegradation reactor, the reactor was connected with a circulating water bath pump to stabilize the system at 40°C, the initial pH of the octadecylamine solution was 3, the output wavelength of the xenon lamp light source was set to 320-380 nm, and the light source outlet was 15 cm away from the liquid surface. Samples were taken at 0, 10, 20, 30, 60, 120, 180, and 240 min, respectively, and the concentration of octadecylamine was tested by ultraviolet spectrophotometry. After 4 h of photodegradation, the degradation rate of octadecylamine was 68%. The test results are shown in Table 1. Figure 1

[0043] 1.3 Dodecylmorpholine degradation experiment

[0044] A solution of 100 mg / L dodecylmorpholine + 1 g / L NaCl was placed in a photodegradation reactor, the reactor was connected with a circulating water bath pump to stabilize the system at 40°C, the initial pH of the dodecylmorpholine solution was 3, the output wavelength of the xenon lamp light source was set to 320-380 nm, and the light source outlet was 15 cm away from the liquid surface. Samples were taken at 0, 10, 20, 30, 60, 120, 180, and 240 min, respectively, and the concentration of dodecylmorpholine was tested by ultraviolet spectrophotometry. After 4 h of photodegradation, the degradation rate of dodecylmorpholine was 76%. The test results are shown in Table 2. Figure 1

[0045] Example 2 Adjusting the particle size of the synthesized anatase titanium dioxide particles by adjusting the amount of HF 2.1:

[0047] Step 1: 1.95 mL of deionized water and 55.8 mL of glacial acetic acid were added to the polytetrafluoroethylene liner, 0.3 mL of a 40 wt% hydrofluoric acid solution was added, and then 20.0 mL of tetrabutyl titanate was added dropwise to the solution while stirring, and the stirring was continued for 30 min;

[0048] Step 2: The liner was placed in a reaction kettle and placed in a 180°C oven for 24 h. After the reaction kettle was naturally cooled to room temperature, the collected precipitate was washed with anhydrous ethanol and deionized water for 3 times, respectively;

[0049] Step 3: The precipitate was dried in a 60°C oven for 6 h, and then the sample was calcined at 400°C in a muffle furnace for 2 h to remove organic volatile impurities. Undoped anatase titanium dioxide photocatalytic material was obtained. The SEM of the synthesized material is shown in Table 3. Figure 2.1 2.2:

[0051] ​​​Step 1: Add 1.95 mL of deionized water and 55.8 mL of glacial acetic acid to the polytetrafluoroethylene inner liner, add 0.7 mL of 40 wt% hydrofluoric acid solution, and then add 20.0 mL of tetrabutyl titanate dropwise to the solution while stirring, and continue stirring for 30 min.

[0052] Step 2: Place the inner liner in the reaction vessel and react in a 180℃ oven for 24 hours. After the reaction vessel has cooled naturally to room temperature, wash the collected precipitate three times each with anhydrous ethanol and deionized water.

[0053] Step 3: The precipitate was dried in a 60℃ oven for 6 hours, and then calcined in a muffle furnace at 400℃ for 2 hours to remove volatile organic impurities. Undoped anatase titanium dioxide photocatalyst material was obtained. SEM images of the synthesized material are shown below. Figure 2.2 As shown. 2.3:

[0055] Step 1: Add 1.95 mL of deionized water and 55.8 mL of glacial acetic acid to the polytetrafluoroethylene inner liner, add 1.0 mL of 40 wt% hydrofluoric acid solution, and then add 20.0 mL of tetrabutyl titanate dropwise to the solution while stirring, and continue stirring for 30 min.

[0056] Step 2: Place the inner liner in the reaction vessel and keep it in a 180℃ oven for 24 hours. After the reaction vessel cools naturally to room temperature, wash the collected precipitate three times each with anhydrous ethanol and deionized water.

[0057] Step 3: The precipitate was dried in a 60℃ oven for 6 hours, and then calcined in a muffle furnace at 400℃ for 2 hours to remove volatile organic impurities. Undoped anatase titanium dioxide photocatalyst material was obtained. SEM images of the synthesized material are shown below. Figure 2.3 As shown.

[0058] As the amount of HF increases, the (001) crystal plane of the synthesized TiO2 is gradually exposed. When the amount of HF is 0.7 mL, the morphology is cubic with uniform particle size. At this time, the photocatalytic activity is the highest, and the degradation rate of octadecylamine and dodecylmorpholine is improved. As the amount of HF further increases, F- enters the crystal lattice, and the synthesized substance is fluorine-containing TiO2 with larger particles, which is not suitable for photocatalytic reactions.

[0059] Example 1

[0060] 3.1 A 5% black anatase titanium dioxide composite material, prepared by the following method:

[0061] Step 1, 1.95 mL of deionized water and 55.8 mL of glacial acetic acid were added into a polytetrafluoroethylene liner, 0.7 mL of 40 wt% hydrofluoric acid solution was added, 0.15 g of black titanium dioxide material was added, and stirring was performed at a speed of 400 r / min for 30 min.

[0062] Step 2, 20.0 mL of tetrabutyl titanate was added dropwise into the solution, and stirring was continued at a speed of 400 r / min for 30 min with a magnetic stirrer; under this condition, the hydrolysis rate of tetrabutyl titanate was about 64%, and 0.15 g of black titanium dioxide was added to obtain a 5% black titanium dioxide doped anatase titanium dioxide composite material.

[0063] Step 3, the liner was placed in a reaction kettle and placed in a 180°C oven for 24 h. After the reaction kettle was naturally cooled to room temperature, the collected precipitate was washed with anhydrous ethanol and deionized water for 3 times respectively;

[0064] Step 4, the precipitate was dried in a 60°C oven for 6 h, and then the sample was calcined in a muffle furnace at 400°C for 2 h to remove organic volatile impurities. A 5 wt% black titanium dioxide doped anatase titanium dioxide photocatalytic material was obtained. The SEM image of the material is shown in Figure 3 . 3.2

[0066] A 100 mg / L octadecylamine + 1 g / L NaCl solution was placed in a photodegradation reactor, the reactor was connected with a circulating water bath pump, the system was stabilized at 40°C, the initial pH of the octadecylamine solution was 3, the output wavelength of the xenon lamp light source was set to 320-380 nm, and the distance between the light outlet of the light source and the liquid surface was 15 cm. Samples were taken at 0, 10, 20, 30, 60, 120, 180, and 240 min respectively, and the concentration of octadecylamine was tested by ultraviolet spectrophotometry. After 4 h of photodegradation, the degradation rate of octadecylamine could reach 78%. The test results are shown in Figure 4 . 3.3

[0068] A 100 mg / L dodecylmorpholine + 1 g / L NaCl solution was placed in a photodegradation reactor, the reactor was connected with a circulating water bath pump, the system was stabilized at 40°C, the initial pH of the dodecylmorpholine solution was 3, the output wavelength of the xenon lamp light source was set to 320-380 nm, and the distance between the light outlet of the light source and the liquid surface was 15 cm. Samples were taken at 0, 10, 20, 30, 60, 120, 180, and 240 min respectively, and the concentration of dodecylmorpholine was tested by ultraviolet spectrophotometry. After 4 h of photodegradation, the degradation rate of dodecylmorpholine could reach 87%. The test results are shown in Figure 4 .

[0069] Example 2

[0070] 4.1 A 5wt% black titania + 5wt% α-Fe2O3 doped anatase titania composite material was prepared by the following method:

[0071] Step 1, 1.95 mL of deionized water and 55.8 mL of glacial acetic acid were added to the inner container of polytetrafluoroethylene, 0.7 mL of 40wt% concentrated hydrofluoric acid solution was added, 0.15 g of black titania material and 0.15 g of α-Fe2O3 material were added, and the mixture was stirred at a speed of 400 r / min by a magnetic stirrer for 30 min. Under this condition, the hydrolysis rate of tetrabutyl titanate was about 64%, and 0.15 g of black titania material and 0.15 g of α-Fe2O3 were added to obtain a 5wt% black titania + 5wt% α-Fe2O3 doped anatase titania composite material.

[0072] Step 2, 20.0 mL of tetrabutyl titanate was added dropwise to the solution, and the stirring was continued at a speed of 400 r / min for 30 min;

[0073] Step 3, the inner container was placed in a reaction kettle and placed in a 180°C oven for 24 h. After the reaction kettle was naturally cooled to room temperature, the collected precipitate was washed with anhydrous ethanol and deionized water for 3 times respectively;

[0074] Step 4, the precipitate was dried in a 60°C oven for 6 h, and then the sample was calcined in a muffle furnace at 400°C for 2 h to remove organic volatile impurities. A 5wt% black titania + 5wt% α-Fe2O3 doped anatase titania photocatalytic material was obtained. 4.2

[0076] A 100 mg / L octadecylamine + 1 g / L NaCl solution was placed in a photodegradation reactor, the reactor was connected with a circulating water bath pump to make the system stable at 40°C, the initial pH of the octadecylamine solution was 3, the xenon lamp light source output wavelength was set to 320-380 nm, and the light source outlet was 15 cm away from the liquid surface. Samples were taken at 0, 10, 20, 30, 60, 120, 180, and 240 min, and the concentration of octadecylamine was tested by ultraviolet spectrophotometer. After 4 h of photodegradation, the degradation rate of octadecylamine could reach 88.5%. The test results are shown in Figure 5 4.3

[0078] ​The 100mg / L dodecyl morpholine + 1g / L NaCl solution was put into a photodegradation reactor, the reactor was connected with a circulating water bath pump to make the system stable at 40℃, the initial pH of the dodecyl morpholine solution was 3, the wavelength of the xenon lamp light source was set to 320-380nm, and the distance between the light source outlet and the liquid surface was 15cm. Samples were taken at 0, 10, 20, 30, 60, 120, 180, and 240min, and the concentration change of dodecyl morpholine was tested by ultraviolet spectrophotometry. After 4h of photodegradation, the degradation rate of dodecyl morpholine could reach 96.2%. The test results are shown in Table 1. Figure 5

[0079] By comparing with the degradation efficiency of octadecylamine and dodecyl morpholine by the undoped TiO2 in Comparative Example 1, the band gap of the material doped with α-iron oxide, γ-iron oxide, and black titanium dioxide is reduced, which can respond to a wider spectral range and increase the photocatalytic performance, thereby improving the degradation rate of octadecylamine and dodecyl morpholine. Before and after doping, the particle size of the synthesized photocatalyst can be adjusted by adjusting the amount of hydrofluoric acid added.

[0080] The relational terms such as "first" and "second" are only used to distinguish one from another of identical name, and do not necessarily require or imply any such actual relationship or order between the parts.

[0081] The above has exemplarily described the present application, and it should be noted that any simple modification, change or other equivalent replacement without creative labor by those skilled in the art without departing from the core of the present application falls within the protection scope of the present application.​

Claims

1. Use of a wide spectrum, low cost photocatalytic degradation material for degrading potassium salt flotation collector octadecylamine and / or dodecylmorpholine, characterized in that, The preparation method of the wide-spectrum, low-cost photocatalytic degradation material comprises the following steps: hydrofluoric acid is added into acetic acid solution to obtain a first solution, alkyl titanate and a doping substance are added into the first solution, and a first mixture is obtained after stirring uniformly, the first mixture is transferred into a reaction kettle, and reaction is carried out at 150-300 DEG C for 12-30 h, after the reaction is completed, the precipitate is collected and washed and dried to obtain the wide-spectrum, low-cost photocatalytic degradation material; the molar fraction of acetic acid in the first solution is 70-90%; the molar fraction of hydrofluoric acid in the first solution is 1.0-8.0%; the doping substance is one or more of black titanium dioxide, alpha-ferric oxide and gamma-ferric oxide; the addition amount of the alkyl titanate is 0.5%-4.5% of the molar fraction of acetic acid; the addition amount of the doping substance is 0.075 wt%-7.5 wt% of the mass of the alkyl titanate; the alkyl titanate is one or more of tetrabutyl titanate, tetraethyl titanate and tetraisopropyl titanate.

2. Use according to claim 1, characterized in that, when the doping substance is alpha-ferric oxide and / or gamma-ferric oxide, the alkyl titanate and the doping substance are added into the first solution, and the pH of the first solution is ensured to be 3.0-4.0, and the addition amount of the doping substance is 0.075 wt%-7.5 wt% of the mass of the alkyl titanate.

3. Use according to claim 1, characterized in that, the black titanium dioxide is prepared by the following method: sodium tetrahydroborate and titanium dioxide are mixed in a mass ratio of 1:1-1:5, grinded and stirred uniformly, and then placed in a tube furnace to reduce the titanium dioxide by high-temperature reduction, the reduction temperature is 350 DEG C-500 DEG C, the reduction time is 1-3 h, and the reduction protective atmosphere is nitrogen, helium or argon, the reduced product is washed with deionized water for 2-4 times, dried, and the black titanium dioxide is obtained.

4. Use according to claim 3, characterized in that, the reduction protective atmosphere is argon.

5. The use according to claim 1, characterized in that, the dried precipitate is calcined at 400 DEG C-600 DEG C for 2-10 h to obtain the wide-spectrum, low-cost photocatalytic degradation material.

6. The use according to claim 1, characterized in that, the alkyl titanate is added in a slow addition manner.

7. The use according to claim 1, characterized in that, the particle size of the wide-spectrum, low-cost photocatalytic degradation material is adjusted by adjusting the addition amount of hydrofluoric acid in the first solution.

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