CN114797906A - BiOCl @ Bi 2 S 3 In-situ synthesis method and application of composite material - Google Patents

Abstract

The invention discloses BiOCl @ Bi ₂ S ₃ The in-situ synthesis method of the composite material and the application thereof comprise the following steps: (1) dissolving a bismuth source in an alcohol solution to obtain a solution A; (2) mixing vitamin B ₁ Dissolving hydrochloride in water to obtain a solution B, and then adding the solution B into the solution A under stirring to obtain a mixed solution C; (3) carrying out hydrothermal treatment on the mixed solution C, and carrying out solid-liquid separation, washing and drying to obtain the BiOCl @ Bi ₂ S ₃ A composite material. The invention uses vitamin B ₁ The hydrochloride is used as a chlorine source and a sulfur source and is used as a surfactant, and vitamin B is added after bismuth oxychloride is generated ₁ The in-situ etching of the sulfur source decomposed by the hydrochloride is beneficial to BiOCl and Bi ₂ S ₃ Heterojunction is compositely constructed, separation of photoproduction electrons and holes is promoted, degradation of antibiotics and volatile organic pollutants (VOCs) can be efficiently catalyzed under the condition of visible light, and activity of the catalyst is almost unchanged after the catalyst is recycled for many times.

Description

A kind of in situ synthesis method of BiOCl@Bi2S3 composite and its application

technical field

The invention belongs to the technical field of material preparation and environmental protection, and in particular relates to an in-situ synthesis method of a BiOCl@Bi ₂ S ₃ composite material and its application in visible light catalyzed antibiotic degradation and VOCs degradation.

Background technique

Visible light catalysis technology is used to completely mineralize and degrade toxic and harmful organic pollutants in the environment by directly utilizing solar energy through semiconductor photocatalytic materials. It is a low-cost green general technology and has good application prospects in the field of environmental protection. The key to visible light catalysis technology is the development of efficient and stable semiconductor catalysts. At present, semiconductor photocatalysts mainly have the following problems: (1) Some semiconductor materials have low light absorption efficiency, and can only absorb ultraviolet light (only 4% of the energy of sunlight); (2) Photogenerated holes and electrons are easy to recombine, The separation efficiency is low; (3) the preparation process of the photocatalyst is complicated, and toxic and harmful solvents or structure-directing agents need to be introduced; (4) the photocatalyst is difficult to achieve large-scale production. Therefore, it is of great significance to develop a green, simple, and easy-to-scale photocatalyst synthesis method to prepare efficient and stable visible light catalysts.

Both BiOCl and Bi ₂ S ₃ materials have a layered structure, and their forbidden band widths are 3.0-3.5 eV and 1.3-1.7 eV, respectively. BiOCl has a large forbidden band width and usually only has better photocatalytic activity in the ultraviolet region. Bi ₂ S ₃ has a narrow band gap and is a potential photocatalyst that responds to visible light. However, due to its relatively close valence band and conduction band, the photogenerated electron-hole recombination rate is high, and it generally needs to be recombined with other materials. showed good catalytic activity. It has been reported in the literature that BiOCl and Bi ₂ S ₃ are composited to construct a heterojunction, which is not only beneficial to improve the absorption of visible light and the generation of photogenerated electrons and holes, but also to promote the separation of photogenerated electrons and holes and improve the photocatalytic performance.

At present, the synthesis of BiOCl and Bi ₂ S ₃ composite materials is generally carried out by hydrolysis, water (solvent) thermal method, alcohol thermal method, soft template method, high temperature solid phase method and inverse microemulsion method. The source is etched, and the synthesis process is complicated, and generally needs to add acid or alkali and surfactant.

SUMMARY OF THE INVENTION

In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a method for in-situ synthesis of BiOCl@Bi ₂ S ₃ composite materials, using vitamin B ₁ hydrochloride as a chlorine source and a sulfur source, and simultaneously as a surface _The active agent, after the formation _of bismuth oxychloride, is etched in situ by the sulfur source decomposed by vitamin B1 hydrochloride, which is conducive to the composite construction _of BiOCl and Bi2S3 to build a heterojunction, and promotes the separation of photogenerated electrons and holes, which can be used in visible light. Under the same conditions, the degradation of antibiotics and volatile organic pollutants (VOCs) can be efficiently catalyzed, and the activity of the catalyst is almost unchanged after repeated use.

For solving the above problems, the technical scheme adopted in the present invention is:

An in-situ synthesis method of BiOCl@Bi ₂ S ₃ composite material, comprising the following steps:

(1) bismuth source is dissolved in alcohol solution to obtain solution A;

(2) dissolving vitamin B ₁ hydrochloride in water to obtain solution B, then adding solution B to solution A under stirring to obtain mixed solution C;

(3) The mixed solution C is subjected to hydrothermal treatment, and the BiOCl@Bi ₂ S ₃ composite material is obtained through solid-liquid separation, washing and drying.

Preferably, in step (1), the bismuth source is selected from one or more of bismuth nitrate pentahydrate, bismuth chloride and bismuth citrate.

Preferably, in step (1), the alcohol is selected from one or more of methanol, ethanol, isopropanol, ethylene glycol, and glycerol.

Preferably, in step (1), in the solution A, the concentration of the bismuth source is 0.05-0.2 mol/L.

Preferably, in step (2), in the solution B, the concentration of vitamin B ₁ hydrochloride is 0.1-0.5 mol/L.

Preferably, in step (2), the molar ratio of the bismuth source and vitamin B ₁ hydrochloride is 1-5:1.

Preferably, in step (3), the temperature of the hydrothermal treatment is 80-160° C., and the time is 6-24 h.

The invention also provides the application of the synthesized BiOCl@Bi ₂ S ₃ composite material as a photocatalyst for the degradation of antibiotics or VOCs under visible light;

The specific steps are as follows: at room temperature, the BiOCl@Bi ₂ S ₃ composite material is added to water with an antibiotic concentration of 15-150 mg/L or gas with a VOCs concentration of 0.2-2 mg/L, and the reaction is sufficient for 0.1-12 h.

Preferably, the antibiotic is selected from one or more of ciprofloxacin, norfloxacin, ofloxacin, tetracycline, sulfamethoxazole, sulfamethazine and oxytetracycline, and the BiOCl The mass ratio of @Bi ₂ S ₃ composites to antibiotics is 1:0.01~0.1.

Preferably, the VOCs are selected from one or more of formaldehyde, toluene, benzene and xylene, and the mass ratio of the BiOCl@Bi ₂ S ₃ composite material to the VOCs is 1:0.005-0.05.

Compared with the prior art, the technical effect of the present invention is:

1. In the present invention, vitamin B ₁ hydrochloride is used as both a chlorine source and a sulfur source, and also as a surfactant, which is conducive to the formation of a uniform structure and avoids the use of acids, alkalis and surfactants.

2. The present invention adopts an in-situ synthesis method, and after the bismuth oxychloride is generated, it is etched in-situ by a sulfur source decomposed by vitamin B ₁ hydrochloride, which is conducive to the construction of a heterojunction and promotes the separation of photogenerated electrons and holes.

3. The BiOCl@Bi ₂ S ₃ composite material in the present invention can efficiently catalyze the degradation of antibiotics and VOCs under visible light, and the catalytic material can be recycled.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

Example 1

At room temperature, 5mmol of bismuth nitrate pentahydrate was weighed and dissolved in 100mL of ethylene glycol solution to obtain solution A; 5mmol of vitamin B ₁ hydrochloride was dissolved in 10mL of water to obtain solution B; then under stirring, solution B was slowly added dropwise to In solution A, mixed solution C was obtained; the mixed solution C was placed in a crystallization kettle and sealed, treated at 160 °C for 6 h, washed and dried after cooling, and the obtained material was denoted as BiOCl@Bi ₂ S ₃ -1 composite material.

Example 2

At room temperature, 5mmol of bismuth citrate pentahydrate was weighed and dissolved in 50mL of isopropanol solution to obtain solution A; 1mmol of vitamin B ₁ hydrochloride was dissolved in 10mL of water to obtain solution B; then solution B was slowly added dropwise under stirring into solution A to obtain mixed solution C; the mixed solution C was placed in a crystallization kettle and sealed, treated at 105 °C for 12 h, washed and dried after cooling, and the obtained material was recorded as BiOCl@Bi ₂ S ₃ -2 composite material.

Example 3

At room temperature, 5mmol of bismuth chloride pentahydrate was weighed and dissolved in 25mL of ethanol solution to obtain solution A; 2mmol of vitamin B ₁ hydrochloride was dissolved in 10mL of water to obtain solution B; then solution B was slowly added dropwise to the solution under stirring. In A, mixed solution C was obtained; the mixed solution C was placed in a crystallization kettle and sealed, treated at 80°C for 24 h, washed and dried after cooling, and the obtained material was recorded as BiOCl@Bi ₂ S ₃ -3 composite material.

Example 4

At room temperature, 5mmol of bismuth nitrate pentahydrate was weighed and dissolved in 50mL of ethylene glycol solution to obtain solution A; 1.67mmol of vitamin B ₁ hydrochloride was dissolved in 10mL of water to obtain solution B; then solution B was slowly added dropwise under stirring Put the mixed solution C into the solution A to obtain the mixed solution C; after the mixed solution C was placed in a crystallization kettle and sealed, treated at 135 °C for 12 h, washed and dried after cooling, and the obtained material was recorded as BiOCl@Bi ₂ S ₃ -4 composite material.

Comparative Example 1

At room temperature, 5mmol of bismuth nitrate pentahydrate was weighed and dissolved in 50mL of ethylene glycol solution to obtain solution A; 2.5mmol of vitamin B ₁ hydrochloride was dissolved in 10mL of water to obtain solution B; then solution B was slowly added dropwise under stirring into solution A, stirred for 12 h, washed and dried after cooling, and the obtained material was designated as BiOCl.

Comparative Example 2

At room temperature, 5mmol of bismuth nitrate pentahydrate was weighed and dissolved in 50 mL of ethylene glycol solution to obtain solution A; 10 mmol of Na ₂ S was dissolved in 30 mL of water to obtain solution B; then solution B was slowly added dropwise to solution A under stirring, Stirred for 12 h, washed and dried after cooling, and the obtained material was designated as Bi ₂ S ₃ .

Comparative Example 3

Weigh 1.3g BiOCl (5mmol) prepared in Comparative Example 1 and ultrasonically disperse it in 50mL of ethylene glycol to obtain dispersion A; Weigh 1.28g Bi ₂ S3 (2.5mmol) prepared in Comparative Example ₂ and ultrasonically disperse it in 20mL of water to obtain dispersion Liquid B; the dispersion liquid B was slowly added dropwise to the dispersion liquid A, stirred for 12 h, washed and dried, and the obtained material was denoted as BiOCl@Bi ₂ S ₃ -5.

Antibiotic degradation:

At room temperature, 40 mg of the materials prepared in Examples 1-4 and Comparative Examples 1-3 were added to 40 mL of an aqueous solution containing a certain concentration of antibiotics for 15 minutes in the dark, and the reaction was dark for 30 minutes. The 300W xenon light source was turned on, and the reaction was filtered after a certain period of time. Remove the catalyst, detect the residual concentration, and calculate the degradation rate as shown in Table 1:

Table 1 Antibiotic degradation rate data table

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 antibiotic Ciprofloxacin oxytetracycline Ofloxacin norfloxacin norfloxacin norfloxacin norfloxacin Degradation time (h) 12 7.5 4.5 1 1 1 1 Initial concentration (mg/L) 100 60 45 10 10 10 10 Residual concentration (mg/L) 3.5 4.1 2.8 0.12 5.8 6.9 3.2 Degradation rate(%) 96.5 93.2 93.8 98.8 42 31 68

Table 2 The BiOCl@Bi ₂ S ₃ -1 catalytic initial concentration of Example 1 is 100 mg/L ciprofloxacin degradation and recycling performance

1 cycle cycle 2 times cycle 3 times cycle 4 times cycle 5 times Degradation rate(%) 96.5 96.3 96.0 96.0 95.8

Note: After a single use, it can be reused after filtering, washing and drying.

Degradation of VOCs:

At room temperature, 100 mg of the materials prepared in Example 1-4 and Comparative Example 1-3 were added to 250 mL of VOCs gas of a certain concentration, and the 300W xenon light source was turned on. After a certain time of reaction, a gas sampler was used to sample and detect the residual concentration, and calculate the residual concentration. The adsorption rate is shown in Table 3:

Table 3 VOCs degradation rate data table

Table 4 The photocatalytic initial concentration of BiOCl@Bi ₂ S ₃ -4 in Example 4 is 1 mg/L formaldehyde gas degradation and recycling performance

1 cycle cycle 2 times cycle 3 times cycle 4 times cycle 5 times Degradation rate(%) 99.2 99.1 99.1 99.0 98.7

Note: After a single use is completed, it can be reused directly.

Claims (10)

1. an in-situ synthesis method of BiOCl@Bi ₂ S ₃ composite material, is characterized in that, comprises the steps: (1) bismuth source is dissolved in alcohol solution to obtain solution A; (2) dissolving vitamin B ₁ hydrochloride in water to obtain solution B, then adding solution B to solution A under stirring to obtain mixed solution C; (3) The mixed solution C is subjected to hydrothermal treatment, and the BiOCl@Bi ₂ S ₃ composite material is obtained through solid-liquid separation, washing and drying. 2. in-situ synthesis method according to claim 1, is characterized in that: in step (1), described bismuth source is selected from one or more in bismuth nitrate pentahydrate, bismuth chloride, bismuth citrate. 3. in-situ synthesis method according to claim 1, is characterized in that: in step (1), described alcohol is selected from one or more in methanol, ethanol, isopropanol, ethylene glycol, glycerol kind. 4. The in-situ synthesis method according to claim 1, characterized in that: in step (1), in the solution A, the concentration of the bismuth source is 0.05-0.2 mol/L. The in-situ synthesis method according to claim 1, characterized in that: in step (2), in the solution B, the concentration of vitamin B ₁ hydrochloride is 0.1-0.5 mol/L. 6. the in-situ synthesis method of a kind of BiOCl@Bi ₂ S ₃ composite material according to claim ₁ , is characterized in that: in step (2), the mol ratio of described bismuth source and vitamin B hydrochloride is 1 to 5:1,. 7 . The in-situ synthesis method according to claim 1 , wherein in the step (3), the temperature of the hydrothermal treatment is 80-160° C., and the time is 6-24 h. 8 . 8. the application of the BiOCl@Bi ₂ S ₃ composite material synthesized by the in-situ synthesis method described in any one of claims 1-7, is characterized in that: it is used as the photocatalyst that antibiotics or VOCs degrade under visible light; The specific steps are as follows: at room temperature, the BiOCl@Bi ₂ S ₃ composite material is added to water with an antibiotic concentration of 15-150 mg/L or gas with a VOCs concentration of 0.2-2 mg/L, and the reaction is sufficient for 0.1-12 h. 9. the application of BiOCl@Bi ₂ S ₃ composite material according to claim 8, is characterized in that: described antibiotic is selected from ciprofloxacin, norfloxacin, ofloxacin, tetracycline, sulfamethoxazole , one or more of sulfamethazine and oxytetracycline, and the mass ratio of the BiOCl@Bi ₂ S ₃ composite material to the antibiotic is 1:0.01-0.1. 10. the application of BiOCl@Bi ₂ S ₃ composite material according to claim 8, is characterized in that: The VOCs are selected from one or more of formaldehyde, toluene, benzene and xylene, and the mass ratio of the BiOCl@Bi ₂ S ₃ composite material to the VOCs is 1:0.005-0.05.