Preparation method of TiO2 / BiVO4 composite material for degrading ibuprofen residual pollutants in water environment

Abstract

The invention relates to preparation of a titanium dioxide and bismuth vanadate composite photocatalytic material and application of the titanium dioxide and bismuth vanadate composite photocatalytic material in ibuprofen-containing sewage treatment, and belongs to the technical field of photocatalysis and water pollution treatment. The titanium dioxide (TiO2) and bismuth vanadate (BiVO4) photocatalytic material is prepared by adopting a water bath and calcination method. Under ultraviolet irradiation, the material can effectively degrade ibuprofen residual pollutants in a water body and convert the ibuprofen residual pollutants into harmless small molecules or mineralize the ibuprofen residual pollutants into carbon dioxide and water, the degradation rate reaches 99% or above, and excellent cycle stability is still kept in five stability tests. The photocatalyst is green and non-toxic in raw material, low in cost, simple in preparation process, capable of decontaminating ibuprofen in a water body, simple in process and high in decontaminating effect, an environment-friendly and efficient water treatment method is provided, ibuprofen residual pollutants in a water environment can be effectively removed, the influence on a water body ecological system is reduced, and the water body ecological system is protected. Wide application prospects are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of novel catalysts and the treatment of water environment pollutants, and specifically relates to a preparation method and an application process of a TiO2 / BiVO4 photocatalyst for degrading ibuprofen residual pollutants in the water environment. Background Art

[0002] In recent years, the medical and health industry in China has developed rapidly, and the production volume of the medical industry has also increased year by year, resulting in a growing number of organic pollutants in the environment. Among them, drug residue pollution has attracted wide attention. Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) commonly used to relieve mild to moderate pain and fever, and has been widely used in the medical field. In recent years, especially under the influence of the novel coronavirus, ibuprofen, as a main treatment drug, has led to a large amount of ibuprofen being stockpiled. When ibuprofen drugs expire, if not disposed of properly, they will pollute the environment and cause certain harm to the ecosystem. Therefore, it is particularly important to develop an efficient and environmentally friendly ibuprofen purification treatment technology. Photocatalytic degradation is a method of degrading organic substances into harmless substances by using a photocatalyst under the action of light, and has the advantages of high efficiency, environmental protection, no by-products, etc., and has been widely used in the treatment of organic pollutants in recent years. TiO2 is one of the most widely used photocatalysts, and its main advantages are high photocatalytic efficiency, good chemical stability, non-toxicity, etc. However, pure-phase TiO2 has a relatively wide band gap, requires higher energy for excitation, has a low solar energy utilization rate, and the removal efficiency of ibuprofen in the water environment is not particularly significant. BiVO4 is an n-type semiconductor material and has received extensive research attention due to its wide light absorption range, suitable band edge position, and non-toxicity. However, due to its narrow band gap and low redox ability, the removal rate of ibuprofen under visible light irradiation by pure-phase BiVO4 is only 45%. However, the formation of a composite of TiO2 and BiVO4 can expand the photocatalytic response range, enhance the redox ability of the system, and prolong the reusability of the catalyst, and it shows excellent activity in the process of degrading ibuprofen. Based on TiO2 and BiVO4, this patent adopts a preparation method of water bath and calcination to compound TiO2 and BiVO4, and successfully prepares a photocatalyst with low cost, simple preparation, and environmental friendliness, which can efficiently remove ibuprofen residual pollutants in the water environment. Summary of the Invention

[0003] The present invention aims to provide a preparation method and an application process of a TiO2 / BiVO4 catalyst for photocatalytic degradation of ibuprofen residual pollutants in the water environment under economic and environmental protection conditions.

[0004] 1. The preparation scheme of the catalyst is as follows: Step 1: Add TiO2 into the ethylene glycol solution and stir for 0.5 h to obtain solution A. Then add Bi(NO3)3 and NH4VO3 into the ethylene glycol solution and stir for 0.5 h to obtain solution B. Then mix solutions A and B and stir for 0.5 h.

[0005] Step 2: After the mixing solution is stirred, put it into a single-neck flask and reflux and heat it in an oil bath at 80 °C for 2 h to obtain the TiO2 / BiVO4 composite, and let it stand for 12 h. Centrifuge, wash, dry and grind to obtain a powdery sample.

[0006] Step 3: Calcinate the powdery sample obtained in Step 2 in a muffle furnace at 400 °C for 3 h to finally obtain the TiO2 / BiVO4 catalyst, named TiO2 / BVO.

[0007] 2. Application of the catalyst material prepared in the present invention in photocatalytic degradation of ibuprofen residues: Add 20 mg of TiO2 / BVO catalyst and 20 mL of ibuprofen solution (25 mg / L) into a quartz glass tube in sequence. First, carry out a dark reaction for 0.5 h in a photoreaction instrument to make the system reach the adsorption-desorption equilibrium. Then turn on the ultraviolet mercury lamp for a 1 h photoreaction. Samples are taken every 15 min and filtered through a 0.22 µm filter membrane. The obtained supernatant is analyzed by liquid chromatography. The final ibuprofen removal rate is 99.84%.

[0008] The beneficial effects of the present invention are as follows: (1) The catalyst preparation process flow of the present invention is simple, efficient, does not require complex equipment, and the raw materials used are non-toxic and low in cost. The catalyst has the potential for large-scale industrial preparation and industrial application.

[0009] (2) The TiO2 / BVO catalyst prepared in the present invention can efficiently degrade ibuprofen residue pollutants in the water environment, has high and stable catalytic activity, will not cause secondary pollution to the environment, and has broad application prospects. Description of the Drawings

[0010] Figure 1 It is a synthesis schematic diagram of the prepared sample.

[0011] Figure 2 It is the X-ray powder diffraction pattern of the prepared sample.

[0012] Figure 3 It is the scanning electron microscope image of the prepared sample. (a) is TiO2, (b) is BiVO4, (c) is TiO2 / BVO. The scanning results show that TiO2 is a spherical structure, BiVO4 is a fusiform structure, and TiO2 / BVO presents a fusiform rod-like structure loaded with nanospheres.

[0013] Figure 4 X-ray photoelectron spectroscopy of the prepared samples, (a) is the 2p orbital of Ti, (b) is the 1s orbital of O, (c) is the 4f orbital of Bi, and (d) is the 2p orbital of V.

[0014] Figure 5 Specific surface area and pore diameter of the prepared samples; the specific surface areas of TiO2 and BiVO4 are 6.605 m 2 g -1 and 5.350 m 2 g -1 , and the specific surface area of TiO2 / BVO is 19.067 m 2 g -1 . This is mainly because the titanium dioxide nanospherical particles are dispersed and aggregated on the surface of bismuth vanadate, significantly increasing the total surface area of the material, and more pores or microporous structures may be formed during the synthesis of the composite material. These pores increase the specific surface area and may also improve the adsorption and catalytic properties of the material.

[0015] Figure 6 Photocatalytic degradation curves of ibuprofen solution (25 mg / L) by TiO2, BiVO4 and TiO2 / BVO under ultraviolet light irradiation for 1 h. The removal rate of ibuprofen by TiO2 / BVO reached more than 99% within 1 h, and the performance was far greater than that of pure TiO2 (70.08%) and BiVO4 (41.74%), indicating that TiO2 / BVO has excellent photocatalytic performance.

[0016] Figure 7 Photocatalytic degradation of ibuprofen solutions with different initial concentrations by TiO2 / BVO. This material has a higher removal rate for ibuprofen solutions in the concentration range of (10 - 50 mg / L), indicating its good photocatalytic performance and abundant surface active sites. This enables it to exhibit efficient and stable performance in the degradation of pollutants at different concentrations and is suitable for environmental purification.

[0017] Figure 8 Five-cycle experiment of photocatalytic degradation of 25 mg / L ibuprofen solution by TiO2 / BVO. After 5 cycles, the removal rate of ibuprofen by the material still remained above 98%, indicating that the material has efficient and stable catalytic performance, excellent durability and anti-pollution ability, showing good regeneration ability and broad practical application potential.

[0018] Figure 9 X-ray powder diffraction pattern of TiO2 / BVO after five cycles of ibuprofen degradation. After 5 cycles, the X-ray powder diffraction pattern after cycling hardly changed significantly, further demonstrating the excellent stability of the material. Specific implementation mode

[0019] The present invention will be further described below in conjunction with specific embodiments. Embodiment

[0020] 20 mg of TiO2 / BVO catalyst and 20 mL of ibuprofen solution (10 mg / L) were successively added into a quartz glass tube. First, a 0.5 h dark reaction was carried out in a photoreaction instrument to make the system reach the adsorption-desorption equilibrium. Subsequently, the ultraviolet mercury lamp was turned on for a 1 h photoreaction. Samples were taken every 15 min and passed through a 0.22 µm filter membrane. The obtained supernatant was analyzed by liquid chromatography. The final ibuprofen removal rate was 89.92%. Embodiment

[0021] 20 mg of TiO2 / BVO catalyst and 20 mL of ibuprofen solution (40 mg / L) were successively added into a quartz glass tube. First, a 0.5 h dark reaction was carried out in a photoreaction instrument to make the system reach the adsorption-desorption equilibrium. Subsequently, the ultraviolet mercury lamp was turned on for a 1 h photoreaction. Samples were taken every 15 min and passed through a 0.22 µm filter membrane. The obtained supernatant was analyzed by liquid chromatography. The final ibuprofen removal rate was 94.98%. Embodiment

[0022] 2 mg of TiO2 / BVO catalyst and 20 mL of ibuprofen solution (25 mg / L) were successively added into a quartz glass tube. First, a 0.5 h dark reaction was carried out in a photoreaction instrument to make the system reach the adsorption-desorption equilibrium. Subsequently, the ultraviolet mercury lamp was turned on for a 1 h photoreaction. Samples were taken every 15 min and passed through a 0.22 µm filter membrane. The obtained supernatant was analyzed by liquid chromatography. The final ibuprofen removal rate was 65.58%. Embodiment

[0023] 30 mg of TiO2 / BVO catalyst and 20 mL of ibuprofen solution (25 mg / L) were successively added into a quartz glass tube. First, a 0.5 h dark reaction was carried out in a photoreaction instrument to make the system reach the adsorption-desorption equilibrium. Subsequently, the ultraviolet mercury lamp was turned on for a 1 h photoreaction. Samples were taken every 15 min and passed through a 0.22 µm filter membrane. The obtained supernatant was analyzed by liquid chromatography. The final ibuprofen removal rate was 98.07%.

Claims

1. A method for preparing a TiO2 / BiVO4 composite material for degrading ibuprofen residual pollutants in an aqueous environment, characterized in that , follow these steps: Step 1. At room temperature, add 1 mmol TiO2 to 20 mL ethylene glycol solution and stir to obtain solution A. Then add 2 mmol Bi(NO3)3 and 2 mmol NH4VO3 to 20 mL ethylene glycol solution and stir evenly to obtain solution B. Then mix solutions A and B and stir for 30 min.

2. Step 2: After the mixed solution is stirred, it is placed in a single-necked flask and refluxed at 80 °C in an oil bath to obtain a TiO2 / BiVO4 composite, which is then allowed to stand at room temperature for 12 h. It is then centrifuged, washed, dried and ground to obtain a powdered sample.

3. Step 3: Place the powdered sample in step 2 in a muffle furnace and calcine at 400°C for 3 h at a heating rate of 10°C / min to finally obtain a TiO2 / BiVO4 composite material.

4. The use of the TiO2 / BiVO4 photocatalyst prepared by the preparation method of the TiO2 / BiVO4 composite material for degradation of ibuprofen residual pollutants in an aquatic environment according to claim 1 in degradation of ibuprofen residual pollutants in an aquatic environment, characterized in that: 20 mg TiO2 / BVO catalyst and 20 mL ibuprofen solution (25 mg / L) were added to a quartz glass tube in sequence. After 0.5 h of dark reaction, the solution was irradiated with a UV mercury lamp for 1 h. Samples were taken every 15 min and filtered through a 0.22 µm filter membrane for analysis by liquid chromatography. The final ibuprofen removal rate was 99.84%.

5. The method for preparing the catalyst according to claim 1, characterized in that: The molar ratio of TiO2, Bi(NO3)3 and NH4VO3 is 1:2:

2.

6. The method for preparing the catalyst according to claim 1, characterized in that: TiO2 and BiVO4 are first molecularly combined at a medium temperature, and then calcined at a high temperature in a muffle furnace at a heating rate of 10°C / min to form a catalyst with high stability and good crystallinity.

7. The use of the TiO2 / BiVO4 photocatalyst in the degradation of ibuprofen residual pollutants in an aqueous environment according to claim 2, characterized in that: Ultraviolet mercury lamp is the light source for photocatalytic reaction.

8. Use of the TiO2 / BiVO4 composite material obtained by the preparation method according to claim 1, characterized in that: Used for photocatalytic degradation of ibuprofen residual pollutants under ambient temperature and pressure.

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