阅读说明：本技术 一种改性硅藻土负载BiVO4-BiOCl异质结的复合材料及应用 (Modified diatomite-loaded BiVO4-BiOCl heterojunction composite material and application ) 是由 张继斌 张爱娟 余丽 于 2021-01-18 设计创作，主要内容包括：本发明涉及硅藻土复合材料技术领域,且公开了一种改性硅藻土负载BiVO-4-BiOCl异质结的复合材料,在硅藻土表面引入丰富的氨基和亚氨基,大量的氨基和亚氨基的可以作为活性吸附位点,使改性硅藻土可以通过氢键缔合和静电作用等作用,对四环素等污染物进行有效吸附,实现对硅藻土的功能化改性,BiOCl纳米花和Zn掺杂介孔状BiVO-4形成p-n异质结,促进光生电子和空穴的分离,进一步与水反应生成羟基自由基和超氧自由基等活性物质,首先改性硅藻土对四环素进行氢键缔合和静电作用进行有效吸附,然后将其光催化降解为无毒的小分子,从而实现对四环素的高效吸附和光催化降解过程。(The invention relates to the technical field of diatomite composite materials, and discloses a modified diatomite-loaded BiVO 4 The composite material of the BiOCl heterojunction is characterized in that abundant amino groups and imino groups are introduced on the surface of diatomite, and a large number of amino groups and imino groups can be used as active adsorption sites, so that modified diatomite can effectively adsorb pollutants such as tetracycline through the effects of hydrogen bond association, electrostatic action and the like, and the functionalized modification of the diatomite is realized, and BiOCl nanoflowers and Zn-doped mesoporous BiVO (BiVO) 4 The method is characterized in that a p-n heterojunction is formed, separation of photoproduction electrons and cavities is promoted, active substances such as hydroxyl radicals and superoxide radicals are further generated by reaction with water, modified diatomite is firstly subjected to hydrogen bond association and electrostatic action for effective adsorption of tetracycline, and then the tetracycline is degraded into non-toxic small molecules through photocatalysis, so that the high-efficiency adsorption and photocatalytic degradation processes of the tetracycline are realized.)

1. Modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions, characterized in that: the modified diatomite carries BiVO₄The preparation method of the composite material of the BiOCl heterojunction comprises the following steps:

(1) adding a sodium hydroxide solution with the mass fraction of 2-4% and diatomite into a beaker, performing ultrasonic treatment and stirring for preactivation for 2-6h, filtering a solvent, washing a product to be neutral by deionized water, and drying to obtain activated diatomite;

(2) adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding an epoxy silane coupling agent, carrying out epoxidation reaction, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain epoxy modified diatomite;

(3) adding an acetone solvent, epoxy modified diatomite and triethylene tetramine into a round-bottom flask, carrying out ultrasonic treatment, carrying out amino modification reaction, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain amino modified diatomite;

(4) adding glycol solvent, amino modified diatomite and Bi (NO) into a beaker₃)₃And KCl, stirring for 6-24 hours after ultrasonic treatment, pouring the solution into a reaction kettle, carrying out in-situ solvothermal reaction, cooling, filtering the solvent, washing the mixed product with deionized water, and drying to obtain the modified diatomite-loaded BiOCl nanoflower;

(5) adding a nitric acid solution with pH of 5-6 and Bi (NO) into a beaker₃)₃Adding NH after stirring and dissolving₄VO₃、Zn(NO₃)₂And cetyl trimethyl ammonium bromide serving as a surfactant, uniformly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction, cooling, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the Zn-doped mesoporous BiVO₄；

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker₄Carrying out ultrasonic treatment for 1-3h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

2. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: the epoxy silane coupling agent in the step (2) is 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane or 3- [ (2,3) -glycidoxypropyl ] trimethoxysilane]The mass ratio of one of the propyl methyl dimethoxy silane to the epoxy silane coupling agent is 100: 25-60.

3. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: the epoxidation reaction in the step (2) is carried out for 15-30h at the temperature of 30-50 ℃.

4. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: the mass ratio of the epoxy modified diatomite to the triethylene tetramine in the step (3) is 100: 60-150.

5. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: the amino modification reaction in the step (3) is carried out for 6-12h at the temperature of 30-60 ℃.

6. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: in the step (4), the amino is modified by diatomite and Bi (NO)₃)₃The mass ratio of the KCl to the KCl is 100:4-10: 0.8-2.

7. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: the in-situ solvothermal reaction in the step (4) is carried out at the temperature of 140 ℃ and 160 ℃ for 12-24 h.

8. The modified diatomite-loaded BiVO of claim 1₄-BiOCl heterojunctionThe composite material of (2), characterized in that: bi (NO) in the step (5)₃)₃、NH₄VO₃、Zn(NO₃)₂And the mass ratio of the cetyl trimethyl ammonium bromide to the cetyl trimethyl ammonium bromide is 100:28-32: 40-65.

9. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: the hydrothermal reaction in the step (5) is carried out at the temperature of 170-190 ℃ for 2-5 h.

10. The modified diatomite-loaded BiVO of claim 1₄-a composite of BiOCl heterojunctions, characterized in that: the modified diatomite loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO in the step (5)₄The mass ratio of (A) to (B) is 100: 15-40.

Technical Field

The invention relates to the technical field of diatomite composite materials, in particular to a modified diatomite-loaded BiVO₄-BiOCl heterojunction composite material and application.

Background

Tetracycline is a traditional antibiotic and is widely applied in the fields of agriculture, medicine and the like, but tetracycline is difficult to degrade in nature, so that tetracycline is continuously accumulated in a biosphere along with a biological chain, and serious harm is caused to human health, animal reproduction and an ecological system₂、CdS、BiVO₄And BiOCl and the like, wherein the photocatalytic degradation method is mainly characterized in that electrons are excited and transited by light irradiation on a photocatalyst to generate a photon-generated carrier, and further generate hydroxyl radicals with extremely strong activity and the like to degrade pollutants into nontoxic micromolecules.

The diatomite is a natural siliceous sedimentary rock, is rich in reserve, cheap and easily available, is biologically friendly, has no pollution, has the characteristics of high specific surface area, rich microporous structure, strong adsorbability and the like, has wide application prospects in the fields of drug carriers, catalyst carriers, environmental protection, water pollution treatment and the like, needs to be chemically modified in order to further expand the practical application of the diatomite, has unique functions to meet the application in the aspects of adsorption and treatment of pollutants such as tetracycline and the like, and can be used as BiVO₄And a photocatalyst carrier such as BiOCl, and the like, thereby obtaining the composite material with high adsorption performance and dual functions of photocatalytic degradation.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a modified diatomite loaded BiVO₄The composite material of the BiOCl heterojunction and the application thereof have excellent adsorption and photocatalytic degradation performances on pollutants such as tetracycline and the like.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: modified diatomite-loaded BiVO₄-BiOCl heterojunction of composite material, said modified diatomaceous earth supporting BiVO₄The preparation method of the composite material of the BiOCl heterojunction comprises the following steps:

(1) adding 2-4% by mass of sodium hydroxide solution and diatomite into a beaker, performing ultrasonic treatment and stirring for preactivation for 2-6h, filtering the solvent, washing the product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding an epoxy silane coupling agent, carrying out epoxidation reaction, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine into a round-bottom flask, carrying out ultrasonic treatment, carrying out amino modification reaction, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite and Bi (NO) into a beaker₃)₃And KCl, stirring for 6-24 hours after ultrasonic treatment, pouring the solution into a reaction kettle, carrying out in-situ solvothermal reaction, cooling, filtering the solvent, washing the mixed product with deionized water, and drying to obtain the modified diatomite-loaded BiOCl nanoflower.

(5) Adding a nitric acid solution with pH of 5-6 and Bi (NO) into a beaker₃)₃Adding NH after stirring and dissolving₄VO₃、Zn(NO₃)₂Mixing with cetyl trimethyl ammonium bromide as surfactant, stirring, adding the solution into a reaction kettle, performing hydrothermal reaction, cooling, filtering, adding ethanol, and removingWashing the product with water and drying to obtain the Zn-doped mesoporous BiVO₄。

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker₄Carrying out ultrasonic treatment for 1-3h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Preferably, the epoxy silane coupling agent in the step (2) is one of 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane or 3- [ (2,3) -glycidoxy ] propylmethyldimethoxysilane, and the mass ratio of the epoxy silane coupling agent to the epoxy silane coupling agent is 100: 25-60.

Preferably, the epoxidation reaction in the step (2) is carried out at 30-50 ℃ for 15-30 h.

Preferably, the mass ratio of the epoxy modified diatomite to the triethylene tetramine in the step (3) is 100: 60-150.

Preferably, the amino modification reaction in the step (3) is carried out at 30-60 ℃ for 6-12 h.

Preferably, the amino group in the step (4) is modified diatomite or Bi (NO)₃)₃The mass ratio of the KCl to the KCl is 100:4-10: 0.8-2.

Preferably, the in-situ solvothermal reaction in the step (4) is carried out at 140 ℃ and 160 ℃ for 12-24 h.

Preferably, Bi (NO) is used in said step (5)₃)₃、NH₄VO₃、Zn(NO₃)₂And the mass ratio of the cetyl trimethyl ammonium bromide to the cetyl trimethyl ammonium bromide is 100:28-32: 40-65.

Preferably, the hydrothermal reaction in the step (5) is carried out at 190 ℃ and 170 ℃ for 2-5 h.

Preferably, the modified diatomite loaded with BiOCl nanoflowers and Zn-doped mesoporous BiVO in the step (5)₄The mass ratio of (A) to (B) is 100: 15-40.

(III) advantageous technical effects

Compared with the prior art, the invention has the following chemical mechanism and beneficial technical effects:

the modified diatomite-loaded BiVO₄The BiOCl heterojunction composite material is prepared by pre-activating kieselguhr by sodium hydroxide, further modifying by an epoxy silane coupling agent to obtain epoxy modified kieselguhr, and then performing ring-opening addition reaction on an introduced epoxy group and an amino group of triethylene tetramine to obtain amino modified kieselguhr, so that abundant amino and imino groups are introduced to the surface of the kieselguhr and can be used as active adsorption sites, and the modified kieselguhr can effectively adsorb pollutants such as tetracycline and the like through the effects of hydrogen bond association, electrostatic action and the like, so that the functionalized modification of the kieselguhr is realized.

The modified diatomite-loaded BiVO₄The composite material of the BiOCl heterojunction takes amino modified diatomite with high specific surface area as a carrier, and Bi (NO) is added in a solvothermal reaction system of ethylene glycol₃)₃And KCl is on the surface of the modified diatomite to generate BiOCl with a unique flower-like structure and a high specific surface area in situ, so that BiOCl nanoflowers uniformly grow on the surface of the diatomite, the BiOCl nanoflowers are better dispersed, and the agglomeration phenomenon is improved.

The modified diatomite-loaded BiVO₄-BiOCl heterojunction composite material with cetyltrimethylammonium bromide as surfactant, Zn (NO)₃)₂As a zinc source, Zn-doped mesoporous BiVO is obtained through hydrothermal reaction₄The mesoporous BiVO has a large number of pore structures and a higher specific surface area, is favorable for absorbing light radiation, and Zn is doped to replace Bi crystal lattices to generate impurity energy levels so that the mesoporous BiVO is₄The light absorption edge of the light guide plate is red-shifted, so that the absorption wavelength in the visible light range is widened, and the absorption and the responsiveness to light radiation are further improved.

The modified diatomite-loaded BiVO₄The composite material of the BiOCl heterojunction is prepared by loading modified diatomite with BiOCl nanoflowers and Zn-doped mesoporous BiVO₄Combining to obtain the diatomite-loaded photocatalyst composite material, wherein the BiOCl nanoflowers and the Zn are doped with mesoporous BiVO₄Has a proper energy band structure, forms a p-n heterojunction, and is Zn-doped with BiVO when light is radiated on the heterojunction₄The generated photo-generated electrons transit from the valence band to the conduction bandHoles are left in a valence band, and then a built-in electric field generated by a p-n heterojunction promotes photogenerated electrons generated by a BiOCl valence band to dope Zn with BiVO₄The modified diatomite is firstly subjected to hydrogen bond association and electrostatic action on the tetracycline for effective adsorption, and then is subjected to photocatalytic degradation to form nontoxic micromolecules, so that the processes of efficient adsorption and photocatalytic degradation on the tetracycline are realized.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: modified diatomite-loaded BiVO₄The preparation method of the composite material of the BiOCl heterojunction comprises the following steps:

(1) adding 2-4% by mass of sodium hydroxide solution and diatomite into a beaker, performing ultrasonic treatment and stirring for preactivation for 2-6h, filtering the solvent, washing the product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, adding an epoxy silane coupling agent after ultrasonic treatment, wherein the epoxy silane coupling agent is one of 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane or 3- [ (2,3) -glycidoxy ] propyl methyldimethoxysilane, the mass ratio of the epoxy silane coupling agent to the epoxy silane coupling agent is 100:25-60, carrying out epoxidation reaction for 15-30h at 30-50 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine in a mass ratio of 100:60-150 into a round-bottom flask, performing ultrasonic treatment, performing amino modification reaction for 6-12h at 30-60 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite with the mass ratio of 100:4-10:0.8-2 and Bi (NO) into a beaker₃)₃And KCl, stirring for 6-24h after ultrasonic treatment,and pouring the solution into a reaction kettle, carrying out in-situ solvothermal reaction for 12-24h at the temperature of 140-160 ℃, cooling, filtering the solvent, washing the mixed product with deionized water, and drying to obtain the modified diatomite-loaded BiOCl nanoflower.

(5) Adding a nitric acid solution with pH of 5-6 and Bi (NO) with the mass ratio of 100:28-32:40-65 into a beaker₃)₃、NH₄VO₃、Zn(NO₃)₂And a surfactant of cetyl trimethyl ammonium bromide, evenly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction for 2-5h at the temperature of 190 ℃ with 170-₄。

(6) Adding deionized water and modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker in a mass ratio of 100:15-40₄Carrying out ultrasonic treatment for 1-3h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Example 1

(1) Adding a sodium hydroxide solution with the mass fraction of 2% and diatomite into a beaker, performing ultrasonic treatment and stirring for preactivation treatment for 2 hours, filtering a solvent, washing a product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding 3-glycidyl ether oxypropyl triethoxysilane at a mass ratio of 100:25, carrying out epoxidation reaction for 15 hours at 30 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine in a mass ratio of 100:60 into a round-bottom flask, performing ultrasonic treatment, performing amino modification reaction for 6 hours at 30 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite with the mass ratio of 100:4:0.8 and Bi (NO) into a beaker₃)₃And KCl, stirring for 6h after ultrasonic treatment, pouring the solution into a reactorAnd (3) carrying out in-situ solvothermal reaction for 12h at 140 ℃ in a kettle, cooling, filtering the solvent, washing the mixed product with deionized water, and drying to obtain the modified diatomite-loaded BiOCl nanoflower.

(5) Adding a nitric acid solution with pH of 5 and Bi (NO) with the mass ratio of 100:28:40 into a beaker₃)₃、 NH₄VO₃、Zn(NO₃)₂And cetyl trimethyl ammonium bromide serving as a surfactant, uniformly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction for 2 hours at the temperature of 170 ℃, cooling, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the Zn-doped mesoporous BiVO₄。

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker in a mass ratio of 100:15₄Carrying out ultrasonic treatment for 1h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Example 2

(1) Adding a sodium hydroxide solution with the mass fraction of 4% and diatomite into a beaker, carrying out ultrasonic treatment and stirring for preactivation treatment for 4 hours, filtering the solvent, washing the product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding 3-glycidyl ether oxypropyltrimethoxysilane according to the mass ratio of 100:35, carrying out epoxidation reaction for 15 hours at 40 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine in a mass ratio of 100:90 into a round-bottom flask, performing ultrasonic treatment, performing amino modification reaction for 12 hours at 50 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite with the mass ratio of 100:6:1.2 and Bi (NO) into a beaker₃)₃And KCl, stirring for 12h after ultrasonic treatment, pouring the solution into a reaction kettle, and carrying out in-situ dissolution at 150 DEG CCarrying out thermal reaction for 18h, cooling, filtering the solvent, washing the mixed product with deionized water, and drying to obtain the modified diatomite-loaded BiOCl nanoflower.

(5) Adding a nitric acid solution with pH of 6 and Bi (NO) with the mass ratio of 100:29:48 into a beaker₃)₃、 NH₄VO₃、Zn(NO₃)₂And cetyl trimethyl ammonium bromide serving as a surfactant, uniformly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction for 3 hours at 180 ℃, cooling, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the Zn-doped mesoporous BiVO₄。

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker in a mass ratio of 100:20₄Carrying out ultrasonic treatment for 3h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Example 3

(1) Adding 3% by mass of sodium hydroxide solution and diatomite into a beaker, performing ultrasonic treatment and stirring for preactivation for 4 hours, filtering the solvent, washing the product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding 3- [ (2,3) -glycidoxy ] propyl methyl dimethoxy silane according to the mass ratio of 100:45, carrying out epoxidation reaction at 40 ℃ for 24h, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine in a mass ratio of 100:120 into a round-bottom flask, performing ultrasonic treatment, performing amino modification reaction for 10 hours at 40 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite with the mass ratio of 100:8:1.6 and Bi (NO) into a beaker₃)₃And KCl, stirring for 12h after ultrasonic treatment, pouring the solution into a reaction kettle, carrying out in-situ solvothermal reaction for 18h at 150 ℃, cooling, filtering and dissolvingWashing the mixed product with deionized water and drying to obtain the modified diatomite-loaded BiOCl nanoflower.

(5) Adding a nitric acid solution with pH of 5.5 and Bi (NO) with the mass ratio of 100:31:52 into a beaker₃)₃、 NH₄VO₃、Zn(NO₃)₂And cetyl trimethyl ammonium bromide serving as a surfactant, uniformly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction for 4 hours at 180 ℃, cooling, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the Zn-doped mesoporous BiVO₄。

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker in a mass ratio of 100:30₄Carrying out ultrasonic treatment for 2h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Example 4

(1) Adding 3% by mass of sodium hydroxide solution and diatomite into a beaker, performing ultrasonic treatment and stirring for preactivation treatment for 6 hours, filtering the solvent, washing the product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding 3-glycidyl ether oxypropyl triethoxysilane at a mass ratio of 100:60, carrying out epoxidation reaction for 30 hours at 50 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine in a mass ratio of 100:150 into a round-bottom flask, performing ultrasonic treatment, performing amino modification reaction for 12 hours at 60 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite with the mass ratio of 100:10:2 and Bi (NO) into a beaker₃)₃And KCl, stirring for 24 hours after ultrasonic treatment, pouring the solution into a reaction kettle, carrying out in-situ solvothermal reaction for 24 hours at 160 ℃, cooling, filtering the solvent, washing the mixed product with deionized water and dryingAnd drying to obtain the modified diatomite-loaded BiOCl nanoflower.

(5) Adding a nitric acid solution with pH of 6 and Bi (NO) with the mass ratio of 100:32:65 into a beaker₃)₃、NH₄VO₃、Zn(NO₃)₂And cetyl trimethyl ammonium bromide serving as a surfactant, uniformly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction for 5 hours at 190 ℃, cooling, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the Zn-doped mesoporous BiVO₄。

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker in a mass ratio of 100:40₄Carrying out ultrasonic treatment for 3h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Comparative example 1

(1) Adding a sodium hydroxide solution with the mass fraction of 4% and diatomite into a beaker, carrying out ultrasonic treatment and stirring for preactivation treatment for 3 hours, filtering the solvent, washing the product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding 3-glycidyl ether oxypropyl triethoxysilane at a mass ratio of 100:12, carrying out epoxidation reaction for 30 hours at 50 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine in a mass ratio of 100:30 into a round-bottom flask, performing ultrasonic treatment, performing amino modification reaction for 8 hours at 40 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite with the mass ratio of 100:2:0.4 and Bi (NO) into a beaker₃)₃And KCl, stirring for 12h after ultrasonic treatment, pouring the solution into a reaction kettle, carrying out in-situ solvothermal reaction for 12h at 160 ℃, cooling, filtering the solvent, washing the mixed product with deionized water and drying to obtain the modified diatomite-loaded BiOCl nano-scaleAnd (4) flower.

(5) Adding a nitric acid solution with pH of 6 and Bi (NO) with the mass ratio of 100:27:32 into a beaker₃)₃、 NH₄VO₃、Zn(NO₃)₂And cetyl trimethyl ammonium bromide serving as a surfactant, uniformly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction for 4 hours at 180 ℃, cooling, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the Zn-doped mesoporous BiVO₄。

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker in a mass ratio of 100:7₄Carrying out ultrasonic treatment for 3h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Comparative example 2

(1) Adding a sodium hydroxide solution with the mass fraction of 4% and diatomite into a beaker, carrying out ultrasonic treatment, stirring the pre-activation part for 5 hours, filtering the solvent, washing the product to be neutral by deionized water, and drying to obtain the activated diatomite.

(2) Adding a toluene solvent and activated diatomite into a round-bottom flask, carrying out ultrasonic treatment, adding 3- [ (2,3) -glycidoxy ] propyl methyl dimethoxy silane according to the mass ratio of 100:75, carrying out epoxidation reaction for 15h at 40 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the epoxy modified diatomite.

(3) Adding an acetone solvent, epoxy modified diatomite and triethylene tetramine in a mass ratio of 100:180 into a round-bottom flask, performing ultrasonic treatment, performing amino modification reaction for 12 hours at 30 ℃, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the amino modified diatomite.

(4) Adding glycol solvent, amino modified diatomite with the mass ratio of 100:12:2.5 and Bi (NO) into a beaker₃)₃And KCl, stirring for 12h after ultrasonic treatment, pouring the solution into a reaction kettle, carrying out in-situ solvothermal reaction for 24h at 150 ℃, cooling, filtering the solvent, washing the mixed product with deionized water, and drying to obtain the modified diatomite-loaded BiOCl nanoflower.

(5) Adding a nitric acid solution with pH of 5 and Bi (NO) with the mass ratio of 100:33:75 into a beaker₃)₃、 NH₄VO₃、Zn(NO₃)₂And cetyl trimethyl ammonium bromide serving as a surfactant, uniformly stirring, pouring the solution into a reaction kettle, carrying out hydrothermal reaction for 4 hours at the temperature of 170 ℃, cooling, filtering the solvent, washing the product with ethanol and deionized water, and drying to obtain the Zn-doped mesoporous BiVO₄。

(6) Adding deionized water, modified diatomite-loaded BiOCl nanoflowers and Zn-doped mesoporous BiVO into a beaker in a mass ratio of 100:50₄Carrying out ultrasonic treatment for 2h, and drying the solution in vacuum to prepare the modified diatomite-loaded BiVO₄-a composite of BiOCl heterojunctions.

Adding 500mL of tetracycline solution with the mass fraction of 20mg/L into a beaker, and adding 100mg of modified diatomite-loaded BiVO₄And (3) uniformly stirring the composite material of the BiOCl heterojunction, performing an adsorption process under dark conditions, and measuring the concentration of tetracycline in the solution at different adsorption times by using a UV754N ultraviolet-visible spectrophotometer.

Adding 500mL of tetracycline solution with the mass fraction of 20mg/L into a beaker, and adding 100mg of modified diatomite-loaded BiVO₄And (3) uniformly stirring the BiOCl heterojunction composite material, performing a light degradation process under a 200W xenon lamp, and measuring the concentration of tetracycline in the solution under different adsorption-light degradation times by using a UV754N ultraviolet-visible spectrophotometer.