CN115739118B - Iron-doped bismuth oxygen sulfur photocatalyst and preparation method and application thereof - Google Patents

Abstract

The invention discloses an iron-doped bismuth-oxygen-sulfur photocatalyst, and a preparation method and application thereof, and belongs to the technical field of new environmental catalytic materials. The invention mainly uses Bi ₂ O ₂ S crystal and Fe (NO) ₃ ) ₃ ·9H ₂ O is used as a raw material, and an iron-doped bismuth oxygen sulfur photocatalyst is prepared by adopting a high-energy ball milling method; wherein the doping amount of Fe in the Fe-doped bismuth oxide sulfur photocatalyst is 1.7-5.6%. The iron-doped bismuth oxysulfide photocatalyst obtained by the invention has higher photogenerated carrier transmission efficiency, rich reactive sites and stronger capability of activating persulfate.

Description

An iron-doped bismuth oxysulfur photocatalyst and its preparation method and application

Technical field

The invention belongs to the technical field of new environmental catalytic materials, and specifically relates to an iron-doped bismuth oxygen-sulfur photocatalyst and its preparation method and application.

Background technique

The world's vast quantities of antibiotics are accumulating in the environment through emissions from households, hospitals, pharmaceutical companies, wastewater treatment plants, and aquaculture and livestock farms, driving the emergence of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARBs) in aquatic ecosystems. formation, threatening public health. Tetracycline (TC), as a typical antibiotic, has adverse effects on human health and ecosystems due to its strong chemical stability and environmental persistence. And the antibacterial properties of tetracyclines make them difficult to eradicate using traditional biological wastewater treatment technologies. Therefore, there is an urgent need to develop cost-effective antibiotic wastewater treatment methods.

In recent years, advanced oxidation technology has been widely used to degrade refractory organic pollutants and mineralize them into _CO2 and _H2O. Advanced oxidation technology based on hydroxyl radicals (·OH) and sulfate radicals (SO ₄ ^- ·) is an effective method to degrade common organic pollutants, such as organic dyes, surfactants, hydrocarbons, phenols, and pharmaceutical active ingredients. , pesticides, etc. However, the degradation of organic pollutants by ·OH-based advanced oxidation technology proceeds through non-selective multi-step reactions, which usually require an acidic environment. Compared with the advanced oxidation technology based on ·OH, the advanced oxidation technology based on SO ₄ ^- · has a more stable reaction process, fewer restrictive conditions and a faster reaction rate. It has developed rapidly in recent years, and there are more and more applications in sewage treatment. application.

Currently, many metal ions and heterogeneous catalysts are used in advanced oxidation technologies based on SO ₄ ^- ·. In particular, heterogeneous photocatalysts have great application potential in photocatalytic activation of persulfate to degrade pollutants. In addition, doping transition metals into photocatalysts can significantly improve the catalytic activity of the photocatalyst, achieving the purpose of efficiently activating persulfate to degrade pollutants. However, transition metal doping is usually prepared by hydrothermal or solvothermal methods. This process takes a long time, may cause secondary pollution, and samples cannot be prepared in large quantities.

Contents of the invention

In view of this, the present invention proposes an iron-doped bismuth oxysulfur photocatalyst and its preparation method and application to overcome the above-mentioned shortcomings in the prior art.

In order to achieve the above objects, the present invention proposes the following technical solutions:

An iron-doped bismuth oxysulfur photocatalyst uses Bi ₂ O ₂ S crystal and Fe(NO ₃ ) ₃ ·9H ₂ O as raw materials, and uses a high-energy ball milling method to prepare an iron-doped bismuth oxysulfur photocatalyst; wherein, Fe The doping amount in the iron-doped bismuth oxysulfur photocatalyst is 1.7-5.6%.

Further, the particle size of the Bi ₂ O ₂ S crystal is a nanosheet structure.

The invention also provides a method for preparing an iron-doped bismuth oxysulfur photocatalyst, which includes the following steps:

Using Bi ₂ O ₂ S crystal and Fe(NO ₃ ) ₃ ·9H ₂ O as raw materials, an iron-doped bismuth oxysulfur photocatalyst was prepared using high-energy ball milling method, in which Bi ₂ O ₂ S crystal and Fe(NO ₃ ) The mass ratio of ₃ ·9H ₂ O is 0.5: (0.0625-0.2142).

Further, during the ball milling process, the ball milling transfer intensity was 800 rpm, and the ball milling time was 20 minutes.

Further, the ball-milled sample was added to water at room temperature and stirred to remove excess iron salt, and then dried.

Furthermore, the stirring time is 120 minutes.

The invention also provides an application of an iron-doped bismuth oxysulfur photocatalyst in photocatalytically activated persulfate treatment of wastewater containing organic matter.

Further, the organic substance is tetracycline.

Compared with the prior art, the beneficial effects of the present invention are:

1) The iron-doped bismuth oxysulfur photocatalyst in the present invention is prepared by high-energy ball milling, which has the advantages of relatively simple operation, safety, low cost, and can be prepared in large quantities;

2) The obtained iron-doped bismuth oxysulfur photocatalyst has high photogenerated carrier transmission efficiency, abundant reaction active sites and strong ability to activate persulfate, because the iron doping will cause the bismuth oxysulfide to The energy band structure of the sulfur photocatalyst changes and creates new energy levels, which can promote the separation of photogenerated carriers; the surface of the ground bismuth oxysulfur photocatalyst can expose more reactive sites, which is beneficial to persulfate activation of salt;

3) The obtained iron-doped bismuth oxysulfur photocatalyst exhibits excellent photocatalytic activity and stability for persulfate degradation of tetracycline.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is the X-ray diffraction pattern of the iron-doped bismuth oxysulfur photocatalyst prepared in Examples 1-3 of the present invention and the catalyst prepared in the control group;

Figure 2 is a diagram showing the effect of photocatalytic activation of persulfate for the degradation of tetracycline by the iron-doped bismuth oxysulfur photocatalyst prepared in Examples 1-3 of the present invention and the catalyst prepared by the control group;

Figure 3 is a TEM image of the iron-doped bismuth oxysulfur photocatalyst prepared in Example 2 of the present invention;

Figure 4 is an XRD pattern before and after the photocatalytic reaction of the iron-doped bismuth oxysulfur photocatalyst prepared in Example 2 of the present invention;

Figure 5 is a diagram showing the effect of photocatalytic activation of persulfate to degrade tetracycline by the iron-doped bismuth oxysulfur photocatalyst prepared in Example 2, Comparative Example 1, and Comparative Example 2 of the present invention.

Detailed ways

Various exemplary embodiments of the invention will now be described in detail. This detailed description should not be construed as limitations of the invention, but rather as a more detailed description of certain aspects, features and embodiments of the invention.

It should be understood that the terms used in the present invention are only used to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges in the present invention, it should be understood that every intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or value intermediate within a stated range and any other stated value or value intermediate within a stated range is also included within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded from the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials in connection with which the documents relate. In the event of conflict with any incorporated document, the contents of this specification shall prevail.

It will be apparent to those skilled in the art that various modifications and changes can be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to the skilled person from the description of the invention. The specification and examples are intended to be illustrative only.

The words "includes", "includes", "has", "contains", etc. used in this article are all open terms, which mean including but not limited to.

Unless otherwise specified, the "room temperature" mentioned in the present invention is calculated as 25±2°C.

The raw material Fe(NO ₃ ) ₃ ·9H ₂ O (analytically pure) used in the present invention was purchased from Sinopharm Group;

An iron-doped bismuth oxysulfur photocatalyst uses Bi ₂ O ₂ S crystal and Fe(NO ₃ ) ₃ ·9H ₂ O as raw materials, and uses a high-energy ball milling method to prepare an iron-doped bismuth oxysulfur photocatalyst; wherein, Fe The doping amount in the iron-doped bismuth oxysulfur photocatalyst is 1.7-5.6%.

In some preferred embodiments, the Bi ₂ O ₂ S crystal is a nanosheet structure.

The invention also provides a method for preparing an iron-doped bismuth oxysulfur photocatalyst, which includes the following steps:

Using Bi ₂ O ₂ S crystal and Fe(NO ₃ ) ₃ ·9H ₂ O as raw materials, the iron-doped bismuth oxysulfur photocatalyst was prepared by high-energy ball milling method, in which the mass of Bi ₂ O ₂ S crystal was 0.5g; The mass of Fe(NO ₃ ) ₃ ·9H ₂ O is 0.0625-0.2142g, more preferably 0.0625g, 0.125g, or 0.2142g.

In some preferred embodiments, during the ball milling process, the ball milling transfer intensity is 800 rpm, and the ball milling time is 20 minutes.

In some preferred embodiments, the ball-milled sample is added to water at room temperature, stirred, and dried.

In some preferred embodiments, the stirring time is 120 minutes.

The invention also provides an application of an iron-doped bismuth oxygen-sulfur photocatalyst in activating persulfate to degrade tetracycline under simulated sunlight.

Example 1

A preparation method of iron-doped bismuth oxygen-sulfur photocatalyst, the steps are as follows:

1) Weigh 0.5g of Bi ₂ O ₂ S crystals and 0.0625g of Fe(NO ₃ ) ₃ ·9H ₂ O into a ball mill tank, and grind for 20 minutes in a ball mill with a working intensity of 800 rpm to obtain a ball-milled sample;

2) At room temperature, add the ball-milled sample to 250 mL of water and stir for 120 minutes. After washing and drying, an iron-doped bismuth oxysulfide photocatalyst is obtained, labeled 1.7% Fe/BiOS.

Example 2

A preparation method of iron-doped bismuth oxygen-sulfur photocatalyst, the steps are as follows:

1) Weigh 0.5g of Bi ₂ O ₂ S crystals and 0.125g of Fe(NO ₃ ) ₃ ·9H ₂ O into a ball mill tank, and grind for 20 minutes in a ball mill with a working intensity of 800 rpm to obtain a ball-milled sample;

2) At room temperature, add the ball-milled sample to 250 mL of water and stir for 120 minutes. After washing and drying, an iron-doped bismuth oxysulfide photocatalyst is obtained, labeled 3.3% Fe/BiOS.

Example 3

A preparation method of iron-doped bismuth oxygen-sulfur photocatalyst, the steps are as follows:

1) Weigh 0.5g of Bi ₂ O ₂ S crystals and 0.2412g of Fe(NO ₃ ) ₃ ·9H ₂ O into a ball mill tank, and grind them in a ball mill with a working intensity of 800 rpm for 20 minutes to obtain a ball-milled sample;

2) At room temperature, add the ball-milled sample to 250 mL of water and stir for 120 minutes. After washing and drying, an iron-doped bismuth oxysulfide photocatalyst is obtained, labeled 5.6% Fe/BiOS.

Control group 1

A preparation method of iron-doped bismuth oxygen-sulfur photocatalyst, the steps are as follows:

Preparation of Bi ₂ O ₂ S crystals: Add 1.9403g of Bi(NO ₃ ) ₃ ·5H ₂ O to 60 mL of deionized water and stir evenly, then add 0.1522g of SC(NH ₂ ) ₂ and continue stirring for 10 min, then Slowly add 12 g of LiOH·H ₂ O to the above mixed solution, and continue stirring for 60 minutes to form a brown-black mixed solution; transfer the above stirred uniform mixed solution to an 80 mL PPL-lined high-pressure reaction kettle. Place the high-pressure reaction kettle in a blast drying oven, heat it to 200°C, and maintain it at this temperature for 72 hours. After the high-pressure reactor cooled to room temperature, the remaining samples were collected and washed several times with deionized water. Finally, the washed samples were dried in a vacuum drying oven at 60°C for 12 h. The dried samples were collected to obtain a Bi ₂ O ₂ S sample (labeled BiOS).

Figure 1 is the X-ray diffraction pattern of the iron-doped bismuth oxysulfur photocatalyst prepared in Examples 1-3 of the present invention and the catalyst prepared in the control group. It can be seen from the figure that the XRD diffraction peak position of the 1.7% Fe/BiOS prepared in Example 1 corresponds to the standard peak position of Bi ₂ O ₂ S (PDF #34-1493), indicating that Bi ₂ in the doped photocatalyst The physical phase of O ₂ S does not change, and no other impurities are generated; the XRD diffraction peak position of the 3.3% Fe/BiOS prepared in Example 2 corresponds to the standard peak position of Bi ₂ O ₂ S (PDF #34-1493), indicating that doping The Bi ₂ O ₂ S phase in the doped photocatalyst does not change, and no other impurities are generated; the XRD diffraction peak position of the 5.6% Fe/BiOS prepared in Example 3 is consistent with that of Bi ₂ O ₂ S (PDF#34-1493 ) corresponds to the standard peak position, indicating that the Bi ₂ O ₂ S phase in the doped photocatalyst has not changed and no other impurities are generated.

Application example 1

The iron-doped bismuth oxysulfur photocatalyst prepared in Examples 1-3 and the catalyst prepared in Control 1 were subjected to photocatalytic activation persulfate degradation tetracycline performance test. The specific method is as follows:

Weigh 0.05g of the iron-doped bismuth oxygen-sulfur photocatalyst prepared in Examples 1-3 and the catalyst prepared in Control 1 and add it to 100 mL of a tetracycline solution with a concentration of 30 mg/L. Stir in the dark for 0.5 h to mix the catalyst and pollutants evenly. And to reach adsorption equilibrium, take 5mL of the solution into a centrifuge tube and add 1mL of methanol. Then quickly add 0.03g of persulfate (potassium persulfate was used in this experiment) into the beaker, and turn on the xenon lamp (300W) to illuminate the reaction for 30 minutes. Take 5mL of the solution into the centrifuge tube every 5min, and add 1mL of methanol. Use a spectrophotometer to measure the absorbance of tetracycline at its maximum absorption wavelength of 357 nm. Analyze the changes in tetracycline concentration based on the test results to calculate the degradation effect of the photocatalyst on tetracycline.

Figure 2 is a diagram showing the effect of photocatalytic activation of persulfate to degrade tetracycline by the iron-doped bismuth oxysulfur photocatalyst prepared in Examples 1-3 of the present invention and the catalyst prepared by the control group. As can be seen from Figure 2, in the photocatalytic activation test of persulfate degradation of tetracycline using the 1.7% Fe/BiOS catalyst prepared in Example 1, 83% of the tetracycline was degraded; the 3.3% Fe/BiOS catalyst prepared in Example 2 In the test of photocatalytic activation of persulfate to degrade tetracycline, 90% of tetracycline was degraded; in the test of photocatalytic activation of persulfate to degrade tetracycline, 86% of tetracycline was degraded by the 5.6% Fe/BiOS catalyst prepared in Example 3 ; In the test of photocatalytic activation of persulfate to degrade tetracycline by unmodified Bi ₂ O ₂ S, 57% of the tetracycline was degraded, which shows that the catalyst prepared in Examples 1-3 of the present invention is effective in photocatalytic activation of persulfate. The performance of salt degradation of tetracycline is significantly higher than that of unmodified Bi ₂ O ₂ S.

Figure 3 is a TEM image of the iron-doped bismuth oxysulfur photocatalyst prepared in Example 2 of the present invention. It can be seen from the figure that the iron-doped bismuth oxysulfur photocatalyst prepared by ball milling is in the shape of nanosheets.

Figure 4 is an XRD pattern before and after the photocatalytic reaction of the iron-doped bismuth oxysulfur photocatalyst prepared in Example 2 of the present invention. It can be seen from the figure that the XRD of the iron-doped bismuth oxysulfide photocatalyst before and after the photocatalytic reaction does not change significantly, indicating that the iron-doped bismuth oxysulfide photocatalyst has good stability.

Comparative example 1

Same as Example 2, except that the ball milling time is 10 minutes.

Using the same method as Example 2, the photocatalytic activation persulfate degradation tetracycline performance test was performed. As a result, it was found that 84% of the tetracycline was degraded.

Comparative example 2

Same as Example 2, except that the ball milling time is 40 minutes.

Using the same method as Example 2, the photocatalytic activation persulfate degradation tetracycline performance test was performed. As a result, it was found that 90% of the tetracycline was degraded.

Figure 5 is a diagram showing the effect of photocatalytic activation of persulfate to degrade tetracycline by the iron-doped bismuth oxysulfur photocatalyst prepared in Example 2, Comparative Example 1, and Comparative Example 2 of the present invention. It can be seen from the figure that after 30 minutes of photocatalytic reaction, the iron-doped bismuth oxysulfide photocatalyst obtained by grinding for 10 minutes is less effective in photocatalytically activating persulfate for degrading tetracycline than the iron-doped bismuth oxysulfide photocatalyst obtained by grinding for 20 minutes; The iron-doped bismuth oxysulfur photocatalysts obtained by grinding for 20 minutes and 40 minutes have equivalent photocatalytic activation of persulfate for the degradation of tetracycline. However, considering energy consumption and cost, the method of grinding for 20 minutes to obtain the iron-doped bismuth oxygen-sulfur photocatalyst is more suitable.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. within.

Claims (3)

1. A method for preparing an iron-doped bismuth oxysulfur photocatalyst for photocatalytically activated persulfate treatment of wastewater containing tetracycline, which is characterized in that it includes the following steps: Using Bi ₂ O ₂ S crystal and Fe(NO ₃ ) ₃ ·9H ₂ O as raw materials, an iron-doped bismuth oxysulfur photocatalyst was prepared using high-energy ball milling method, in which Bi ₂ O ₂ S crystal and Fe(NO ₃ ) The mass ratio of ₃ ·9H ₂ O is 0.5: (0.0625-0.2142); The doping amount of Fe in the iron-doped bismuth oxysulfur photocatalyst is 1.7-5.6%; During the ball milling process, the ball milling working intensity is 800rpm and the ball milling time is 20min; The ball-milled sample was added to water at room temperature, stirred for 120 min, and dried. 2. The preparation method according to claim 1, characterized in that the Bi ₂ O ₂ S crystal has a nanosheet structure. 3. Application of an iron-doped bismuth oxysulfur photocatalyst prepared by the preparation method of claim 1 or 2 in photocatalytically activated persulfate treatment of wastewater containing tetracycline.