Sb2S3 / BiVO4 nanoscale photocatalyst as well as preparation method and application thereof

Abstract

The invention discloses a Sb2S3 / BiVO4 nano-scale photocatalyst as well as a preparation method and application of the Sb2S3 / BiVO4 nano-scale photocatalyst. The Sb3S3 / BiVO4 nano-scale photocatalyst synthesized by a hydrothermal method has a good photoresponse signal, hole-electron pairs are easy to separate, more active groups are generated, organic pollutants in oxidized water are oxidized, and the purpose of removing the organic pollutants in the water is achieved. The Sb3S3 / BiVO4 nano-scale photocatalyst disclosed by the invention has the advantages of good chemical stability and excellent circulating effect, and has a wide application prospect in organic pollutant wastewater treatment.

Description

Technical Field

[0001] The present invention belongs to the field of photocatalysts and relates to an Sb 2 S 3 / BiVO 4 nanoscale photocatalyst, its preparation method and application. Background Art

[0002] Methods for organic pollutants in water are mainly divided into physical methods, chemical methods and biological methods. Physical methods generally include sedimentation, flocculation, etc. It only enriches organic substances and does not effectively treat them. Biological methods mainly include activated sludge method, bioenzyme method. The treatment conditions of biological methods are mainly affected by pH, temperature, etc., and the reaction conditions are limited. Chemical methods are often used methods. Among them, advanced oxidation technology is the most efficient and important method for effectively treating organic pollutants in water at present. Advanced oxidation technology is often used in combination with physical methods or chemical methods for the advanced treatment of organic pollutants in water. The photocatalytic technology in advanced oxidation method uses solar energy to separate electron-hole pairs in semiconductor materials, releasing active groups such as hydroxyl radicals (·OH), superoxide radicals (·O 2- ) and singlet oxygen ( 1 O 2 ) to destroy the molecules of organic pollutants in water and achieve the effect of water treatment. Photocatalytic oxidation technology uses solar energy, a green energy source, which is safe and pollution-free and conforms to the environmental protection concept.

[0003] The decomposition of pollutants by heterojunction photocatalysts has attracted great interest in reducing water pollution and environmental pollution. At present, a large number of photocatalysts for the degradation of organic substances have been studied, mainly including metal oxide and non-metal semiconductor materials. Among various metal oxide photocatalysts, bismuth-based photocatalysts such as BiVO 4 , Bi 2 WO 6 , BiOX (X = Cl, Br and I), Bi 2 S 3 and Bi 2 O 3 have been widely studied in recent years. Among them, the BiVO 4 molecule has a tetrahedral structure. This special structure enables the molecule to contact solar energy more fully. The BiVO 4 photocatalyst usually has a high visible light response ability and exhibits certain photocatalytic activity. Sb 3 S 3 is a very excellent photocatalyst. Due to its band gap of -1.84 eV, it has remarkable optoelectronic, electrochemical and optical properties. It has been found through research that its degradation efficiency for organic substances is significant. Therefore, Sb 3 S 3 / BiVO 4The composite material has better photocatalytic degradation performance of organic matter, and this kind of photocatalytic material has never been reported.

[0004] Tetracycline (TC) is a potent, broad-spectrum antibiotic widely used in veterinary and human medicine to address and alleviate a variety of diseases. The affordability and strong effectiveness of tetracycline make it a common and frequently used antibiotic in medical practice. However, TC is not effectively absorbed by the digestive system of animals and humans, resulting in its excretion through feces or urine, usually accounting for 50-80% of the administered dose. It also disrupts the microbial balance within the human intestinal flora. The elimination of harmful and potentially life-threatening organic pollutants is of vital importance. To address this issue, photocatalysis has emerged as an attractive and superior method for this research, with the advantages of simplicity, greenness, low cost and long-lasting durability. Summary of the invention

[0005] The object of the present invention is to provide a Sb 2 S 3 / BiVO 4 Nanoscale photocatalyst and its preparation method and application.

[0006] The technical solution for achieving the purpose of the present invention is as follows:

[0007] Sb 2 S 3 / BiVO 4 The method for preparing a nanoscale photocatalyst comprises the following steps:

[0008] Under stirring conditions, Na 2 The ethylene glycol solution of S was slowly added dropwise to the Sb 2 O 3 ethylene glycol solution, mix well and add BiVO 4 The nanoparticles are stirred until uniformly mixed, and a hydrothermal reaction is carried out at 160-180°C. After the reaction is completed, the mixture is cooled to room temperature, washed, and dried to obtain Sb 2 S 3 / BiVO 4 The photocatalyst, the Sb 2 S 3 / BiVO 4 In photocatalysts, Sb 2 S 3 and BiVO 4 The molar ratio is 1:10~25.

[0009] Preferably, Na 2 In the ethylene glycol solution of S, Na 2 The concentration of S is 0.25 mol / L; Sb 2 O 3 In ethylene glycol solution, Sb2 O 3 The concentration is 0.5mol / L.

[0010] Preferably, the hydrothermal reaction time is 8 to 24 hours.

[0011] Preferably, the washing method is to wash by centrifugation with ethanol and water for 2 to 6 times respectively, and the centrifugal speed is 5000 to 6000 r / min.

[0012] Preferably, the drying temperature is 100-120° C., and the drying time is 2-4 hours.

[0013] The present invention provides Sb obtained by the above preparation method 2 S 3 / BiVO 4 Nanoscale photocatalysts.

[0014] Furthermore, the present invention provides the above-mentioned Sb 2 S 3 / BiVO 4 Application of nanoscale photocatalysts in photocatalytic degradation of organic pollutants.

[0015] The organic pollutants described in the present invention include but are not limited to tetracycline, bisphenol A, dimethyl sulfoxide, rhodamine B, etc.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The present invention aims to improve BiVO 4 The photocatalytic degradation performance of BiVO 4 Sb is introduced into the particles 2 S 3 , Sb was synthesized by a two-step hydrothermal method 2 S 3 / BiVO 4 Composite photocatalyst. This composite binary photocatalyst is more effective than a single catalyst in degrading organic pollutants in water. It forms a heterojunction material, which can easily separate electrons and holes and reduce the recombination of electrons and holes, thereby improving the degradation efficiency of organic pollutants in water. In addition, composite photocatalysts formed by other composite methods (such as Ag / BiVO 4 , gC 3 N 4 / BiVO 4 、TiO 2 / Sb 2 S 3 ) compared to Sb 2 S 3 / BiVO 4Nanoscale photocatalysts have better charge separation and transfer capabilities, releasing more free radical ions, and therefore have better photocatalytic performance.

[0018] (2) Sb of the present invention 2 S 3 / BiVO 4 Nanoscale photocatalysts have good cyclic stability, which facilitates continuous production in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 BiVO 4 Photocatalyst, Ag / BiVO 4 Photocatalyst, gC 3 N 4 / BiVO 4 Degradation efficiency diagram of photocatalyst;

[0020] Figure 2 Sb 2 S 3 Photocatalyst, TiO 2 / Sb 2 S 3 Degradation efficiency diagram of photocatalyst;

[0021] Figure 3 For different Sb 2 S 3 and BiVO 4 Sb prepared under molar ratio conditions 2 S 3 / BiVO 4 Degradation efficiency diagram of photocatalyst;

[0022] Figure 4 Sb 2 S 3 / BiVO 4 =1:25 Photocatalyst photocatalytic treatment of tetracycline wastewater cycle test results. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below, which is only used to explain the present invention and cannot be understood as limiting the present invention.

[0024] The present invention is further described below in conjunction with specific embodiments.

[0025] In the following examples, BiVO 4 The nanoparticles are prepared by conventional methods, as follows:

[0026] 10mmol Bi(NO3 ) 3 ·5H 2 O is dissolved in 30 mL of 2M HNO 3 Solution A was obtained by adding 10mmolNH 3 VO 3 The solution B was dissolved in 30 mL of 2M NaOH, and then the solution B was dropped into the solution A under magnetic stirring. After magnetic stirring for 2 h, the solution was hydrothermally treated at 180 °C. After the reactor was cooled, the formed catalyst particles were centrifuged and washed with ethanol and deionized water in turn, and finally dried at 105 °C for 2 h to obtain BiVO 4 Nanoparticles.

[0027] Example 1

[0028] Sb 2 S 3 / BiVO 4 Preparation of photocatalyst:

[0029] (1) 5 mmol Sb 2 O 3 Add 20 ml of ethylene glycol and sonicate for 30 min until dissolved to obtain solution A. 2 S.9H 2 O was added into 20 ml of ethylene glycol and ultrasonicated for 30 min until dissolved to obtain solution B.

[0030] (2) Solution B was added dropwise into solution A under magnetic stirring. After 2 h of magnetic stirring, the system was homogenized. 50 mol, 125 mol, 250 mol, and 750 mol BiVO were added, respectively. 4 , respectively get Sb 2 S 3 :BiVO 4 =1:10, Sb 2 S 3 :BiVO 4 =1:25, Sb 2 S 3 :BiVO 4 =1:50, Sb 2 S 3 :BiVO 4 =1:150, the catalysts of the four ratios were stirred for 2 h, and hydrothermally treated at 180 °C. When the reactor was cooled to room temperature, the formed catalyst particles were washed with ethanol and deionized water. Finally, the catalyst particles were dried at 120 °C for 2 h to obtain Sb 2 S 3 / BiVO 4 photocatalysts, named Sb 2 S 3 / BiVO 4 =1:10 photocatalyst, Sb 2 S 3 / BiVO 4 =1:25 photocatalyst, Sb 2 S 3 / BiVO 4 =1:50 photocatalyst and Sb 2 S 3 / BiVO 4 =1:150 photocatalyst.

[0031] Comparative Example 1

[0032] Ag / BiVO 4 Preparation of photocatalyst:

[0033] 10mmol Bi(NO 3 ) 3 ·5H 2 O is dissolved in 30 mL of 2M HNO 3 Solution A was obtained by adding 10mmolNH 3 VO 3 Dissolve in 30 mL of 2M NaOH to obtain solution B, add solution B dropwise into solution A under magnetic stirring, and then add 0.005 g of AgNO 3 The powder was magnetically stirred for 2 h and then hydrothermally treated at 180 °C. After the reactor was cooled, the formed catalyst particles were centrifugally washed with ethanol and deionized water in turn, and finally dried at 105 °C for 2 h to obtain the deposited Ag / BiVO 4 Photocatalyst.

[0034] Comparative Example 2

[0035] C 3 N 4 / BiVO 4 Preparation of photocatalyst:

[0036] (1) Add a certain amount of melamine into the porcelain boat, put it into a tube furnace, and heat it to 550℃ at a heating rate of 5℃ / h. Keep the temperature constant for 8h to obtain gC 3 N 4 powder.

[0037] (2) 10 mmol Bi(NO 3 ) 3 ·5H 2 O is dissolved in 30 mL of 2M HNO 3 Solution A was obtained by adding 10 mmol NH 3 VO 3Dissolve in 30 mL of 2M NaOH to obtain solution B. Add solution B dropwise into solution A under magnetic stirring. Then add 3 g gC 3 N 4 The powder was magnetically stirred for 2 h and then hydrothermally treated at 180 °C. After the reactor was cooled, the catalyst particles were washed by centrifugation with ethanol and deionized water in turn, and finally dried at 105 °C for 2 h to obtain gC 3 N 4 / BiVO 4 Photocatalyst.

[0038] Comparative Example 3

[0039] TiO 2 / Sb 2 S 3 Photocatalyst preparation:

[0040] 10mmol Bi(NO 3 ) 3 ·5H 2 O is dissolved in 30 mL of 2M HNO 3 Solution A was obtained by adding 10mmolNH 3 VO 3 Dissolve in 30 mL of 2M NaOH to obtain solution B, drop solution B into solution A under magnetic stirring, and then add 3 g TiO 2 The powder was magnetically stirred for 2 h and then hydrothermally treated at 180 °C. After the reactor was cooled, the catalyst particles were washed by centrifugation with ethanol and deionized water in turn, and finally dried at 105 °C for 2 h to obtain TiO 2 / BiVO 4 Nanoparticles.

[0041] Application Example 1

[0042] Take 1.0g of Sb prepared in Example 1 and Comparative Example respectively 2 S 3 / BiVO 4 Photocatalyst, BiVO 4 、Ag / BiVO 4 , gC 3 N 4 / BiVO 4 , Sb 2 S 3 、TiO 2 / Sb 2 S 3Add to 100ml 20mg / L tetracycline simulated wastewater solution, shade the reaction tube first, conduct dark adsorption reaction, and when the adsorption-desorption equilibrium is reached, conduct light reaction, take samples at regular intervals, test the tetracycline concentration in the reaction tube, and analyze the degradation effect of each photocatalyst. The results are as follows: Figures 1 to 3 shown.

[0043] from Figure 1 It can be seen that after 120 min of photocatalytic degradation, BiVO 4 The removal efficiency of the photocatalyst is 69.1%, Ag / BiVO 4 The removal efficiency of the photocatalyst was 78.1%, gC 3 N 4 / BiVO 4 The removal rate of the photocatalyst was 80.0%; Figure 2 It can be seen that Sb 2 S 3 The removal rate of photocatalyst was 36.5%, TiO 2 / Sb 2 S 3 The removal rate of the photocatalyst was 37.9%; Figure 3 It can be seen that Sb 2 S 3 / BiVO 4 =1:10The removal rate of the photocatalyst is 83.1%, Sb 2 S 3 / BiVO 4 =1:25The removal rate of the photocatalyst is 93.0%, Sb 2 S 3 / BiVO 4 =1:50 The removal rate of the photocatalyst is 69.3%, Sb 2 S 3 / BiVO 4 =1:150The removal rate of the photocatalyst is 66.5%, of which Sb 2 S 3 / BiVO 4 =1:25 The photocatalyst degradation efficiency is the highest.

[0044] Application Example 2

[0045] Using Sb 2 S 3 / BiVO 4 =1:25 photocatalyst was tested on 100mL 20mg / L tetracycline solution in a cycle. After each use, the catalyst was washed 2 to 6 times with ethanol and water respectively by centrifugation at a speed of 5000 to 6000r / min. After drying, it was used again to wash away the organic molecules and inorganic ions adsorbed on the surface. The results are as follows Figure 4 shown.

[0046] from Figure 4 It can be seen that Sb 2 S 3 / BiVO 4 =1:25 The photocatalyst has good stability and there is no significant decrease in the degradation of tetracycline solution after 5 cycles.

Claims

1. A method for preparing a Sb2S3 / BiVO4 nanoscale photocatalyst, characterized in that: The following steps are involved: Under stirring conditions, the ethylene glycol solution of Na2S is slowly added dropwise to the ethylene glycol solution of Sb2O3, and after mixing evenly, BiVO4 nanoparticles are added, stirred until the mixture is evenly mixed, and a hydrothermal reaction is carried out at 160-180°C. After the reaction is completed, the mixture is cooled to room temperature, washed, and dried to obtain a Sb2S3 / BiVO4 photocatalyst. In the Sb2S3 / BiVO4 photocatalyst, the molar ratio of Sb2S3 to BiVO4 is 1:10-25.

2. The preparation method according to claim 1, characterized in that: In the ethylene glycol solution of Na2S, the concentration of Na2S is 0.25 mol / L; in the ethylene glycol solution of Sb2O3, the concentration of Sb2O3 is 0.5 mol / L.

3. The preparation method according to claim 1, characterized in that: The hydrothermal reaction time is 8~24h.

4. The preparation method according to claim 1, characterized in that: The washing method is to centrifuge with ethanol and water for 2 to 6 times respectively, and the centrifugal speed is 5000 to 6000 r / min.

5. The preparation method according to claim 1, characterized in that: The drying temperature is 100~120℃ and the drying time is 2~4h.

6. The Sb2S3 / BiVO4 nanoscale photocatalyst prepared according to the preparation method according to any one of claims 1 to 5.

7. Use of the Sb2S3 / BiVO4 nanoscale photocatalyst according to claim 6 in photocatalytic degradation of organic pollutants.

8. The use according to claim 7, characterized in that: The organic pollutants are tetracycline, bisphenol A, dimethyl sulfoxide or rhodamine B.

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