CN115318336A - Bi 2 WO 6 PTCDA composite photocatalyst and preparation method and application thereof - Google Patents

Abstract

The invention provides a Bi ₂ WO ₆ /PTCDA composite photocatalyst and a preparation method and application thereof, belonging to the technical field of photocatalytic materials. The present invention uses sodium tungstate, bismuth nitrate, 3, 4, 9, 10-perylene tetracarboxylic dianhydride (PTCDA) as raw materials to prepare a uniformly dispersed precursor suspension, which is transferred into a hydrothermal reactor, sealed and placed in a Heat preservation in an oven, natural cooling, washing and drying of the obtained precipitation material for several times to obtain a Bi ₂ WO ₆ /PTCDA composite photocatalyst. The Bi ₂ WO ₆ /PTCDA composite photocatalyst prepared by the invention has good photocatalytic degradation performance for ciprofloxacin, not only has broad application prospects in visible light utilization and environmental protection, but also provides an environment-friendly photocatalyst for designing new ideas.

Description

A kind of Bi2WO6/PTCDA composite photocatalyst and its preparation method and application

technical field

The invention relates to the technical field of photocatalytic materials, in particular to a method for preparing a Bi ₂ WO ₆ /PTCDA composite photocatalyst.

Background technique

With the rapid development of the economy, a large number of endocrine disruptors are continuously released from human production and life, and compounds represented by ciprofloxacin (CIP) are frequently detected in the water environment. CIP, which is difficult to degrade naturally, will destroy the living environment of animals and plants, and pose a great threat to life and health. However, traditional wastewater treatment methods such as biological methods and adsorption methods have problems such as large investment, high operating costs, and secondary pollution, which are difficult to be widely used. Therefore, there is an urgent need for an energy-saving, efficient and environmentally friendly sewage treatment technology to remove CIP.

As a promising wastewater treatment and solar energy development technology, photocatalytic technology has attracted widespread attention due to its low cost, high efficiency, and environmental protection. Photocatalytic technology is a new type of technology based on the special energy band structure of semiconductor materials, and its core is semiconductor photocatalyst.

So far, most photocatalyst materials (TiO ₂ , ZnO, etc.) have weak response to visible light, which greatly limits the utilization of sunlight. In order to utilize solar energy as much as possible, many photocatalysts with visible light activity have been developed. Among them, bismuth tungstate (Bi ₂ WO ₆ ) stands out among many photocatalytic materials due to its low cost, non-toxicity and good visible light responsiveness. However, the easy recombination of photogenerated electron-hole pairs during the reaction process of pure Bi ₂ WO ₆ photocatalyst limits its photocatalytic activity. The existing modification strategies include morphology control, ion doping, and construction of heterojunctions. The present invention adopts a simple hydrothermal method to prepare a Bi ₂ WO ₆ /PTCDA composite photocatalyst, wherein the introduction of PTCDA is conducive to the improvement of photocatalytic performance, and promotes the separation of photogenerated carriers after forming a heterojunction with Bi ₂ WO ₆ with transfer.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a stable, efficient and environmentally friendly Bi ₂ WO ₆ /PTCDA composite photocatalyst and its preparation method and application, so as to improve the separation and transfer efficiency of photogenerated carriers and improve the efficiency of pure Bi ₂ Photocatalytic degradation activity of WO ₆ for ciprofloxacin.

To achieve the above object, the technical scheme of the present invention is as follows:

A Bi ₂ WO ₆ /PTCDA composite photocatalyst, the microscopic appearance of the Bi ₂ WO ₆ /PTCDA is a three-dimensional flower shape.

Further, the preparation method of the above-mentioned Bi ₂ WO ₆ /PTCDA composite photocatalyst includes the following steps:

S1. Dissolve a certain amount of sodium tungstate in deionized water under magnetic stirring, and record it as solution A;

S2, add a certain amount of bismuth nitrate into solution A and continue to stir until completely dissolved, which is recorded as solution B;

S3, disperse a certain amount of PTCDA into deionized water for ultrasonication, and record it as solution C;

S4. Then slowly pour solution C into solution B and stir to form a uniformly dispersed precursor suspension, transfer it to a polytetrafluoroethylene liner and seal it in a stainless steel reactor for hydrothermal reaction;

S5. After the reaction is finished, cool down to room temperature naturally, carry out several times of centrifugal cleaning on the hydrothermal product, then put it into an oven for drying, and grind to obtain a three-dimensional flower-shaped Bi ₂ WO ₆ /PTCDA composite photocatalyst.

Preferably according to the present invention, the mass of sodium tungstate in step S1 is 0.33g, the volume of deionized water is 30mL, the magnetic stirring speed is 500r/min, and the stirring time is 15min.

Preferably according to the present invention, the mass of bismuth nitrate in step S2 is 0.97g, the magnetic stirring speed is 500r/min, and the stirring time is 60min.

Preferably according to the present invention, in step S3, the mass of PTCDA is 0.005-0.05 g, the volume of deionized water is 10 mL, and the ultrasonic time is 30 min.

Preferably according to the present invention, in step S4, the magnetic stirring speed is 500r/min, and the stirring time is 30min; the conditions of the hydrothermal reaction: the hydrothermal temperature is 180°C, and the hydrothermal time is 20h.

Preferably according to the present invention, the reagents used in the centrifugal cleaning treatment in step S5 are deionized water and absolute ethanol.

Preferably according to the present invention, the oven drying conditions in step S5 are as follows: the drying temperature is 80° C., and the drying time is 10-12 hours.

In addition, the present invention also provides the application of a Bi ₂ WO ₆ /PTCDA composite photocatalyst in the photocatalytic degradation of ciprofloxacin.

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

(1) The performance of the Bi ₂ WO ₆ /PTCDA composite photocatalyst prepared by the hydrothermal method is stable, and compared with pure Bi ₂ WO ₆ , it shows higher catalytic activity;

(2) The present invention builds a heterojunction by introducing an organic semiconductor-PTCDA. PTCDA itself has good electrical conductivity and can effectively promote the separation and migration of photogenerated carriers;

(3) The operation steps are simple, the production cost is low, the controllability is high, and the prepared composite photocatalyst has good cycle stability, which provides feasibility for designing an environment-friendly photocatalyst.

Description of drawings

Fig. 1 is the SEM picture of the 2%Bi ₂ WO ₆ /PTCDA composite photocatalyst prepared in embodiment 2;

Fig. 2 is the SEM image of Bi ₂ WO ₆ prepared in the comparative example;

Figure 3 is the XRD pattern of the 2% Bi ₂ WO ₆ /PTCDA composite photocatalyst prepared in Example 2 and the three-dimensional flower-shaped Bi ₂ WO ₆ photocatalyst prepared in the comparative example;

Fig. 4 is a comparison chart of the degradation rate of photocatalytic degradation of ciprofloxacin in the application example.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be noted that those skilled in the art should understand that the details and forms of the scheme of the present invention can be improved and modified without departing from the scope of the present invention, but these improvements and modifications all fall within the protection scope of the present invention.

Embodiment 1: a kind of preparation method of 1%Bi ₂ WO ₆ /PTCDA composite photocatalyst (wherein 1% represents the mass fraction of the PTCDA added, the same below), concrete steps are as follows:

Dissolve 0.33g of sodium tungstate in 30mL of deionized water under magnetic stirring, and call it solution A; then add 0.97g of bismuth nitrate to the above solution, and continue stirring for 60 minutes until it is completely dissolved, and call it solution B; disperse 0.0098g of PTCDA Sonicate in 10mL deionized water for 30 minutes, and record it as solution C; then slowly pour solution C into solution B and stir to form a uniformly dispersed precursor suspension, transfer it to a polytetrafluoroethylene liner and seal it in a stainless steel reactor The hydrothermal reaction was carried out in , the hydrothermal temperature was 180°C, and the hydrothermal time was 20h. After the reaction was finished, it was naturally cooled to room temperature, and the hydrothermal product was successively washed with deionized water and absolute ethanol, dried in an oven at 80°C for 12 hours, and ground to obtain a 1% Bi ₂ WO ₆ /PTCDA composite photocatalyst.

Example 2: A method for preparing a 2% Bi ₂ WO ₆ /PTCDA composite photocatalyst, the specific steps are as follows:

Dissolve 0.33g of sodium tungstate in 30mL of deionized water under magnetic stirring, and record it as solution A; then add 0.97g of bismuth nitrate to the above solution, continue stirring for 60min until it is completely dissolved, and record it as solution B; disperse 0.0198g of PTCDA Sonicate in 10mL deionized water for 30 minutes, and record it as solution C; then slowly pour solution C into solution B and stir to form a uniformly dispersed precursor suspension, transfer it to a polytetrafluoroethylene liner and seal it in a stainless steel reactor The hydrothermal reaction was carried out in , the hydrothermal temperature was 180°C, and the hydrothermal time was 20h. After the reaction was finished, it was naturally cooled to room temperature, and the hydrothermal product was successively washed with deionized water and absolute ethanol, dried in an oven at 80°C for 12 hours, and ground to obtain a 2% Bi ₂ WO ₆ /PTCDA composite photocatalyst.

The SEM picture of the 2% Bi ₂ WO ₆ /PTCDA composite photocatalyst prepared in Example 2 is shown in Figure 1. It can be seen from the figure that some prismatic PTCDA is well fixed on the surface of Bi ₂ WO ₆ , the overall still presents a three-dimensional flower-like microstructure.

Example 3: A method for preparing a 3% Bi ₂ WO ₆ /PTCDA composite photocatalyst, the specific steps are as follows:

Dissolve 0.33g of sodium tungstate in 30mL of deionized water under magnetic stirring, and call it solution A; then add 0.97g of bismuth nitrate to the above solution, continue stirring for 60min until it is completely dissolved, and call it solution B; disperse 0.03g of PTCDA Sonicate in 10mL deionized water for 30 minutes, and record it as solution C; then slowly pour solution C into solution B and stir to form a uniformly dispersed precursor suspension, transfer it to a polytetrafluoroethylene liner and seal it in a stainless steel reactor The hydrothermal reaction was carried out in , the hydrothermal temperature was 180°C, and the hydrothermal time was 20h. After the reaction was finished, it was naturally cooled to room temperature, and the hydrothermal product was sequentially washed with deionized water and absolute ethanol, dried in an oven at 80°C for 12 hours, and ground to obtain a 3% Bi ₂ WO ₆ /PTCDA composite photocatalyst.

Example 4: A method for preparing a 4% Bi ₂ WO ₆ /PTCDA composite photocatalyst, the specific steps are as follows:

Dissolve 0.33g of sodium tungstate in 30mL of deionized water under magnetic stirring, and record it as solution A; then add 0.97g of bismuth nitrate to the above solution, continue stirring for 60min until it is completely dissolved, and record it as solution B; disperse 0.0404g of PTCDA Sonicate in 10mL deionized water for 30 minutes, and record it as solution C; then slowly pour solution C into solution B and stir to form a uniformly dispersed precursor suspension, transfer it to a polytetrafluoroethylene liner and seal it in a stainless steel reactor The hydrothermal reaction was carried out in , the hydrothermal temperature was 180°C, and the hydrothermal time was 20h. After the reaction was finished, it was naturally cooled to room temperature, and the hydrothermal product was centrifugally washed with deionized water and absolute ethanol in sequence, dried in an oven at 80°C for 12 hours, and ground to obtain a 4% Bi ₂ WO ₆ /PTCDA composite photocatalyst.

Comparative example: a kind of preparation method of three-dimensional flower shape Bi ₂ WO ₆ photocatalyst, comprises the following steps:

Dissolve 0.33g of sodium tungstate in 30mL of deionized water under magnetic stirring, then add 0.97g of bismuth nitrate to the above solution, continue to stir for 60min until uniformly mixed, then transfer to the reactor for hydrothermal reaction, the hydrothermal temperature is 180°C, the water heating time is 20h. After the reaction was finished, it was naturally cooled to room temperature, and the hydrothermal product was centrifuged with deionized water and absolute ethanol in turn, put into an oven for 12 hours at 80°C, and ground to obtain a three-dimensional flower-like Bi ₂ WO ₆ photocatalyst.

The SEM image of Bi ₂ WO ₆ prepared in the comparative example is shown in Figure 2. It can be seen from the figure that Bi ₂ WO ₆ presents a three-dimensional flower-like microstructure with a diameter of about 2-3 μm, which is actually composed of a large number of two-dimensional nanosheets Self-assembled.

Application example: photocatalytic degradation of ciprofloxacin

1% Bi ₂ WO ₆ /PTCDA prepared in Example 1 of the present invention, 2% Bi 2 WO ₆ /PTCDA prepared in Example _{2, 3% Bi 2 WO 6} /PTCDA prepared in Example 3, and prepared in Example 4 4% Bi ₂ WO ₆ /PTCDA and the Bi ₂ WO ₆ prepared in the comparative example were used in the photocatalytic degradation experiment of ciprofloxacin. The simulated light sources used in the process were all 500W xenon lamps. The detailed steps are as follows:

50 mg of 1% Bi ₂ WO ₆ /PTCDA prepared in Example 1 of the present invention, 50 mg of 2% Bi ₂ WO ₆ /PTCDA prepared in Example 2, 50 mg of 3% Bi ₂ WO ₆ /PTCDA prepared in Example 3, and 50 mg were implemented The 4% Bi ₂ WO ₆ /PTCDA prepared in example 4 and the Bi ₂ WO ₆ prepared in 50mg comparative example were uniformly dispersed in 100mL 10mg/L ciprofloxacin solution, and stirred for 40min under dark conditions to achieve the photocatalyst and ring Adsorption-desorption equilibrium between profloxacin. After turning on the light source, draw 5 mL of liquid with a medical syringe every 20 min and filter out the solid with a 0.45 μm filter membrane, then measure the absorbance of the solution at 275 nm using a UV-visible spectrophotometer.

Fig. 4 is a comparison chart of degradation efficiency of photocatalytic degradation of ciprofloxacin in this application example. It can be seen from the figure that the composite photocatalysts prepared in Examples 1-4 are better than the Bi ₂ WO ₆ photocatalysts prepared in the comparative examples, and the 2% Bi ₂ WO ₆ /PTCDA composite photocatalysts prepared in Example 2 are better than cyclopropane The photocatalytic degradation efficiency of floxacin is the highest, which can reach 90.18%.

Claims (9)

1. A preparation method of Bi ₂ WO ₆ /PTCDA composite photocatalyst, is characterized in that, specifically comprises the following steps: S1. Dissolve a certain amount of sodium tungstate in deionized water under magnetic stirring, and record it as solution A; S2, add a certain amount of bismuth nitrate into solution A and continue to stir until completely dissolved, which is recorded as solution B; S3, disperse a certain amount of PTCDA into deionized water for ultrasonication, and record it as solution C; S4. Then slowly pour solution C into solution B and stir to form a uniformly dispersed precursor suspension, transfer it to a polytetrafluoroethylene liner and seal it in a stainless steel reactor for hydrothermal reaction; S5. After the reaction is finished, cool down to room temperature naturally, carry out several times of centrifugal cleaning on the hydrothermal product, then put it into an oven for drying, and grind to obtain a three-dimensional flower-shaped Bi ₂ WO ₆ /PTCDA composite photocatalyst. 2. The preparation method of Bi ₂ WO ₆ /PTCDA composite photocatalyst according to claim 1, characterized in that, in the step S1, the mass of sodium tungstate is 0.33g, and the volume of deionized water is 30mL. 3. The preparation method of Bi ₂ WO ₆ /PTCDA composite photocatalyst according to claim 1, characterized in that the mass of bismuth nitrate in the step S2 is 0.97g. 4. The preparation method of Bi ₂ WO ₆ /PTCDA composite photocatalyst according to claim 1, characterized in that, in the step S3, the mass of PTCDA is 0.005-0.05 g, and the volume of deionized water is 10 mL. 5. The preparation method of Bi ₂ WO ₆ /PTCDA composite photocatalyst according to claim 1, characterized in that, the conditions of the hydrothermal reaction in the step S4: the hydrothermal temperature is 160-200°C, and the hydrothermal time is 16～24h. 6 . The preparation method of Bi ₂ WO ₆ /PTCDA composite photocatalyst according to claim 1 , characterized in that, the reagents used in the centrifugal cleaning treatment in the step S5 are deionized water and absolute ethanol. 7 . The preparation method of Bi ₂ WO ₆ /PTCDA composite photocatalyst according to claim 1 , characterized in that the oven drying conditions in the step S5 are as follows: drying temperature is 60-100° C., and drying time is 10-14 hours. 8. A Bi ₂ WO ₆ /PTCDA composite photocatalyst, characterized in that it is prepared by the preparation method according to any one of claims 1-7. 9. The application of the Bi ₂ WO ₆ /PTCDA composite photocatalyst as claimed in claim 8 in the photocatalytic degradation of ciprofloxacin.

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