阅读说明：本技术 氯氧化铋/银/铁酸银三元复合z型光催化剂及其制备方法和应用 (Bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst and preparation method and application thereof ) 是由 郭佳茵 梁婕 袁兴中 曾光明 蒋龙波 于瀚博 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种氯氧化铋/银/铁酸银三元复合Z型光催化剂及其制备方法和应用,该光催化剂是以氯氧化铋为载体,其上包裹有铁酸银,铁酸银上负载有银单质。制备方法包括以下步骤：配制含氯氧化铋、Ag<Sup>+</Sup>、Fe<Sup>3+</Sup>的混合溶液；利用原位沉淀反应制备氯氧化铋/铁酸银复合物；利用还原反应制备氯氧化铋/银/铁酸银三元复合Z型光催化剂。本发明光催化剂具有可见光吸收性能优异、光生电子-空穴分离效率高、光催化活性高、氧化还原能力强、稳定性好、耐腐蚀性能好等优点,能够高效降解抗生素废水,且其制备方法具有合成方法简便、原料成本低、耗能少、耗时短、条件易控等优点,适于连续大规模批量生产,便于工业化利用。(The invention discloses a bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing bismuth and Ag chloride + 、Fe 3+ The mixed solution of (1); preparing a bismuth oxychloride/silver ferrite compound by using an in-situ precipitation reaction; the reduction reaction is utilized to prepare the ternary composite Z-shaped photocatalyst of bismuth oxychloride/silver ferrite. The photocatalyst has the advantages of excellent visible light absorption performance, high photoproduction electron-hole separation efficiency, high photocatalytic activity, strong redox capability, good stability, good corrosion resistance and the like, can efficiently degrade antibiotic wastewater, and the preparation method has simple synthesis methodThe method has the advantages of convenience, low raw material cost, less energy consumption, short time consumption, easily-controlled conditions and the like, is suitable for continuous large-scale batch production, and is convenient for industrial utilization.)

1. The ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite is characterized in that bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst takes bismuth oxychloride as a carrier, silver ferrite is wrapped on the bismuth oxychloride, and a silver simple substance is loaded on the silver ferrite.

2. The ternary composite Z-shaped bismuth oxychloride/silver ferrite photocatalyst of claim 1, wherein the mass percentage of the bismuth oxychloride in the ternary composite Z-shaped bismuth oxychloride/silver ferrite photocatalyst is 10-25%; the bismuth oxychloride has a sheet structure; the silver ferrite is in a granular structure.

3. The preparation method of the ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite as in claim 1 or 2, characterized by comprising the following steps:

s1, mixing bismuth oxychloride with water, ultrasonically dispersing, and adding Ag⁺And Fe³⁺Stirring to obtain bismuth oxychloride and Ag⁺、Fe³⁺The mixed solution of (1);

s2, dropwise adding an alkali solution to the chlorine-containing bismuth oxide and Ag obtained in the step S1⁺、Fe³⁺Carrying out in-situ precipitation reaction in the mixed solution to obtain a bismuth oxychloride/silver ferrite compound;

s3, mixing the bismuth oxychloride/silver ferrite compound obtained in the step S2 with ethanol for reduction reaction to obtain the ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite.

4. The method according to claim 3, wherein in step S1, the bismuth oxychloride is prepared by a method comprising the steps of:

(1) adding bismuth nitrate into ethylene glycol, and stirring until the bismuth nitrate is dissolved to obtain a bismuth nitrate ethylene glycol solution;

(2) adding the bismuth nitrate glycol solution obtained in the step (1) into an ammonium chloride/sodium hydroxide aqueous solution, and stirring to obtain slurry;

(3) and (3) carrying out solvothermal reaction on the slurry obtained in the step (2) to obtain the bismuth oxychloride.

5. The preparation method according to claim 4, wherein in the step (1), the concentration of the bismuth nitrate ethylene glycol solution is 0.25 mmol/mL;

in the step (2), the volume ratio of the bismuth nitrate glycol solution to the ammonium chloride/sodium hydroxide aqueous solution is 1: 6; the mol ratio of ammonium chloride to sodium hydroxide in the aqueous solution of ammonium chloride/sodium hydroxide is 3: 10;

in the step (3), the temperature of the solvothermal reaction is 130-160 ℃; the solvothermal reaction time is 10-18 h.

6. The method according to any one of claims 3 to 5, wherein the bismuth oxychloride (BiSO), Ag, is contained in the step S1⁺、Fe³⁺Bismuth oxychloride and Ag in the mixed solution⁺And Fe³⁺The ratio of (A) to (B) is 19.57-48.93 mg: 0.8-1.5: 1; the ultrasonic dispersion time is 0.5 h-1.5 h; the stirring time is 3-8 h;

in the step S2, the chlorine-containing bismuth oxide and Ag⁺、Fe³⁺The volume ratio of the mixed solution to the alkali solution is 3: 4-12; the alkali solution is sodium hydroxide solution; the concentration of the alkali solution is 1.3M-1.8M;

in the step S3, the reduction reaction is performed under ultrasonic conditions; the power of the ultrasonic wave is 100W; the frequency of the ultrasound is 50 Hz; the ultrasonic time is 1-10 min.

7. The application of the bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst according to claim 1 or 2 or the bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst prepared by the preparation method according to any one of claims 3 to 6 in treatment of antibiotic wastewater.

8. Use according to claim 7, characterized in that it comprises the following steps: mixing a bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst with antibiotic wastewater, stirring under a dark condition to achieve adsorption balance, and carrying out photocatalytic reaction under an illumination condition to complete treatment of the antibiotic wastewater; the addition amount of the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst is 0.3 g-1.0 g of the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst added in each liter of antibiotic wastewater.

9. The use according to claim 8, wherein the antibiotic in the antibiotic wastewater is tetracycline; the concentration of the antibiotics in the antibiotic wastewater is 30 mg/L-50 mg/L.

10. Use according to claim 8 or 9, wherein the stirring time is 1 h; the time of the photocatalytic reaction is more than or equal to 60 min.

Technical Field

The invention belongs to the technical field of photocatalysis, and relates to a bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst, and a preparation method and application thereof.

Background

The application of the semiconductor photocatalyst in the degradation of toxic and harmful organic pollutants (such as antibiotics) has important significance for solving the environmental pollution. However, the wide band gap and low quantum efficiency remain the "bottleneck" of the photocatalyst. Therefore, it is important to actively develop a highly efficient and reproducible photocatalyst having visible light response, and to fully exert the effect of solar energy.

Silver ferrite (AgFeO)₂) The semiconductor is a narrow-bandgap semiconductor (1.15-1.7 eV), can utilize solar energy with a wide spectral range, is easy to be excited by light to generate carriers to participate in the degradation process of pollutants, but has the defects of easy recombination of electron holes, weak redox capability, low quantum efficiency and the like, and greatly limits the application of silver ferrite in the field of photocatalysis. Therefore, how to obtain the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst which has high photoproduction electron-hole separation efficiency, high photocatalytic activity, strong redox capability, good stability and corrosion resistance has very important significance for effectively degrading organic pollutants.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst which has the advantages of excellent visible light absorption performance, high photoproduction electron-hole separation efficiency, high photocatalytic activity, strong redox capability, good stability and good corrosion resistance, and a preparation method and application thereof.

In order to solve the technical problems, the invention adopts the technical scheme that:

the ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite is characterized in that bismuth oxychloride is used as a carrier, silver ferrite is wrapped on the bismuth oxychloride, and a silver simple substance is loaded on the silver ferrite.

In the above-mentioned ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite, what is further improved is that the mass percentage content of bismuth oxychloride in the ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite is 10% -25%; the bismuth oxychloride has a sheet structure; the silver ferrite is in a granular structure.

As a general technical concept, the invention also provides a preparation method of the ternary composite Z-shaped photocatalyst of bismuth oxychloride/silver ferrite, which comprises the following steps:

s1, mixing bismuth oxychloride with water, ultrasonically dispersing, and adding Ag⁺And Fe³⁺Stirring to obtain bismuth oxychloride and Ag⁺、Fe³⁺The mixed solution of (1);

s2, dropwise adding an alkali solution to the chlorine-containing bismuth oxide and Ag obtained in the step S1⁺、Fe³⁺Carrying out in-situ precipitation reaction in the mixed solution to obtain a bismuth oxychloride/silver ferrite compound;

s3, mixing the bismuth oxychloride/silver ferrite compound obtained in the step S2 with ethanol for reduction reaction to obtain the ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite.

In a further improvement of the above preparation method, in step S1, the bismuth oxychloride is prepared by the following steps:

(1) adding bismuth nitrate into ethylene glycol, and stirring until the bismuth nitrate is dissolved to obtain a bismuth nitrate ethylene glycol solution;

(2) adding the bismuth nitrate glycol solution obtained in the step (1) into an ammonium chloride/sodium hydroxide aqueous solution, and stirring to obtain slurry;

(3) and (3) carrying out solvothermal reaction on the slurry obtained in the step (2) to obtain the bismuth oxychloride.

In the above preparation method, further improvement is that, in the step (1), the concentration of the bismuth nitrate glycol solution is 0.25 mmol/mL;

in the step (2), the volume ratio of the bismuth nitrate glycol solution to the ammonium chloride/sodium hydroxide aqueous solution is 1: 6; the mol ratio of ammonium chloride to sodium hydroxide in the aqueous solution of ammonium chloride/sodium hydroxide is 3: 10;

in the step (3), the temperature of the solvothermal reaction is 130-160 ℃; the solvothermal reaction time is 10-18 h.

In the above preparation method, further improvement is that in the step S1, the chlorine-containing bismuth oxide and Ag⁺、Fe³⁺Bismuth oxychloride and Ag in the mixed solution⁺And Fe³⁺The ratio of (A) to (B) is 19.57-48.93 mg: 0.8-1.5: 1; the ultrasonic dispersion time is 0.5 h-1.5 h; the stirring time is 3-8 h;

in the step S2, the chlorine-containing bismuth oxide and Ag⁺、Fe³⁺The volume ratio of the mixed solution to the alkali solution is 3: 4-12; the alkali solution is sodium hydroxide solution; the concentration of the alkali solution is 1.3M-1.8M;

in the step S3, the reduction reaction is performed under ultrasonic conditions; the power of the ultrasonic wave is 100W; the frequency of the ultrasound is 50 Hz; the ultrasonic time is 1-10 min.

As a general technical concept, the invention also provides an application of the bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst or the bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst prepared by the preparation method in treatment of antibiotic wastewater.

The application is further improved, and comprises the following steps: mixing a bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst with antibiotic wastewater, stirring under a dark condition to achieve adsorption balance, and carrying out photocatalytic reaction under an illumination condition to complete treatment of the antibiotic wastewater; the addition amount of the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst is 0.3 g-1.0 g of the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst added in each liter of antibiotic wastewater.

In the above application, further improved, the antibiotic in the antibiotic wastewater is tetracycline; the concentration of the antibiotics in the antibiotic wastewater is 30 mg/L-50 mg/L.

In the above application, further improvement, the stirring time is 1 h; the time of the photocatalytic reaction is more than or equal to 60 min.

The innovation points of the invention are as follows:

aiming at the defects of easy recombination of electron holes, weak redox capability, low quantum efficiency, easy agglomeration and the like of the silver ferrite, the invention creatively combines the silver ferrite with bismuth oxychloride (Bi)₁₂O₁₇Cl₂) Compounding and loading silver simple substance to construct a ternary compound Z-shaped system, wherein the bismuth oxychloride nanosheet in the Z-shaped system not only serves as a photocatalyst to form a heterojunction with silver ferrite, but also serves as a substrate substance to load silver ferrite nanoparticles, so that the agglomeration of the silver oxychloride nanoparticles can be inhibited; the silver simple substance is mainly used as a bridge for electron transfer between bismuth oxychloride and silver ferrite due to the excellent conductivity of the silver simple substance to promote the transfer of electrons according to a Z-shaped path, so that the recombination of photogenerated electrons and holes is reduced, the redox capability of the single silver ferrite is improved, the visible light absorption capability of the system is effectively improved due to the SPR effect of the silver simple substance, and the photocatalyst can better absorb visible light. Meanwhile, the silver ferrite is wrapped on the bismuth oxychloride and loaded with the bismuth oxychloride, and due to the interaction among the bismuth oxychloride, the silver ferrite and the silver simple substance, the dispersibility of the silver ferrite can be improved, and the stability of the silver ferrite and the silver simple substance can be further improved, so that the catalyst has better corrosion resistance. In addition, the photogenerated electrons generated by the Z-type system can reduce the adsorbed oxygen to superoxide radicals, and some superoxide radicals can react with hydrogen ions to generate hydroxyl radicals. It can be seen that the active radicals in the present invention include: the hole, the superoxide radical and the hydroxyl radical can play a role in oxidizing and degrading pollutants, and the photocatalytic performance of the Z-type bismuth oxychloride/silver ferrite ternary heterojunction is further improved.

Compared with the prior art, the invention has the advantages that:

(1) the invention provides a bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst, which takes bismuth oxychloride as a carrier, silver ferrite is wrapped on the bismuth oxychloride, and a silver simple substance is loaded on the silver ferrite, so that the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst has the advantages of excellent visible light absorption performance, high photoproduction electron-hole separation efficiency, high photocatalytic activity, strong redox capability, good stability, good corrosion resistance and the like, and can efficiently degrade antibiotic wastewater. The transfer path of the photo-generated electron-hole of the bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst conforms to a Z-type mechanism.

(2) In the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst, the mass percentage of bismuth oxychloride is optimized to be 10-25%, so that the agglomeration problem of silver ferrite particles can be effectively solved, the dispersibility of the silver ferrite particles is further improved, the crystallinity of the composite photocatalyst can be effectively improved, and the photocatalytic effect of the photocatalyst is further improved, because when the content of bismuth oxychloride is insufficient (for example, the mass percentage is lower than 10%), the silver ferrite particles are easy to agglomerate and do not have a good dispersion effect, so that the photocatalytic effect is poor; when the content of bismuth oxychloride is too high (for example, the mass percentage is higher than 25%), the crystallinity of the composite photocatalyst is deteriorated, so that the photocatalytic effect is reduced.

(3) The invention also provides a preparation method of the bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst, which has the advantages of simple and convenient synthesis method, low raw material cost, less energy consumption, short time consumption, easily-controlled conditions and the like, is suitable for continuous large-scale batch production, and is convenient for industrial utilization.

(4) In the preparation method of the ternary composite Z-shaped photocatalyst of bismuth oxychloride/silver ferrite, ethanol is used as a reducing agent, and the preparation method has the advantages of low toxicity, easy obtainment, economy, difficult secondary pollution and the like.

(5) The invention also provides a bismuth oxychloride/silver ferrite ternary composite Z-shaped photocatalyst which can be used for treating antibiotic wastewater, and has the advantages of simple process, convenient operation, high treatment efficiency, high pollutant degradation efficiency (effect) and the like, and has good practical application prospect.

Drawings

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

FIG. 1 is SEM images of a bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst (20-BAF) prepared in example 3 of the present invention, a bismuth oxychloride nanosheet (BOC), and silver ferrite (AFO) prepared in comparative example 1, wherein a is AFO, b is BOC, and c is 20-BAF.

FIG. 2 is a TEM image of a ternary composite Z-type photocatalyst of bismuth oxychloride/silver ferrite (20-BAF) prepared in example 3 of the present invention, a bismuth oxychloride nanosheet (BOC), and silver ferrite (AFO) prepared in comparative example 1, wherein a is AgFeO₂B is BOC, c and d are 20-BAF.

Fig. 3 is a transient photocurrent intensity diagram of a ternary composite Z-type photocatalyst (20-BAF) of bismuth oxychloride/silver ferrite prepared in example 3 of the present invention, a bismuth oxychloride/silver ferrite composite (20-AF), a bismuth oxychloride nanosheet (BOC), silver ferrite (AFO) prepared in comparative example 1, and silver/silver ferrite composite photocatalyst (AF) prepared in comparative example 2.

Fig. 4 is an impedance diagram of a ternary composite Z-type photocatalyst (20-BAF) of bismuth oxychloride/silver ferrite prepared in example 3 of the present invention, a bismuth oxychloride/silver ferrite composite (20-AF), a bismuth oxychloride nanosheet (BOC), silver ferrite (AFO) prepared in comparative example 1, and silver/silver ferrite composite photocatalyst (AF) prepared in comparative example 2.

FIG. 5 is a graph showing the relationship between time and degradation efficiency when the bismuth oxychloride/silver ferrite ternary composite Z-type photocatalyst (10-BAF, 15-BAF, 20-BAF, 25-BAF), bismuth oxychloride nanosheet (BOC), silver ferrite (AFO), silver ferrite (AF), and bismuth oxychloride/silver ferrite composite (20-BF) in example 5 of the present invention are used for photocatalytic degradation of tetracycline wastewater.

FIG. 6 is a graph showing the effect of the ternary composite Z-type photocatalyst (20-BAF) of bismuth oxychloride/silver ferrite on the cyclic degradation of tetracycline waste water in example 6 of the present invention.

Detailed Description

The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.

The materials and equipment used in the following examples are commercially available.