阅读说明：本技术 一种基于锶掺杂的复合光催化剂及其制备方法和应用 (Composite photocatalyst based on strontium doping and preparation method and application thereof ) 是由 陈晓娟 陈杰明 姚靓 余春沐 梁韵晴 周宇 卢开红 于 2020-11-30 设计创作，主要内容包括：本发明的一种基于锶掺杂的复合光催化剂及其制备方法和应用,所述基于锶掺杂的复合光催化剂为La_(1-x)Sr_xCoO_3和Ag_3PO_4的复合材料,其中,所述La_(1-x)Sr_xCoO_3为富含氧空穴的块体微米结构,所述Ag_3PO_4为不规则的纳米球结构,且Ag_3PO_4分散于La_(1-x)Sr_xCoO_3的表面,构成紧密接触的异质结结构。相较单一的Ag_3PO_4,以及LaCoO_3和Ag_3PO_4的复合材料,本发明所制备的基于锶掺杂的复合光催化剂均具有显著的光生电子-空穴分离效率、光催化活性和稳定性。将制备的复合光催化剂应用于处理含四环素难降解有机废水,具有优异的去除率,达89.27％,且重复利用率高。(The invention relates to a composite photocatalyst based on strontium doping, a preparation method and an application thereof, wherein the composite photocatalyst based on strontium dopingThe photocatalyst is La 1‑x Sr x CoO 3 And Ag 3 PO 4 Wherein the La 1‑x Sr x CoO 3 Is a bulk microstructure of oxygen-rich cavities, the Ag 3 PO 4 Is an irregular nanosphere structure, and Ag 3 PO 4 Dispersed in La 1‑x Sr x CoO 3 The surface of (2) constitutes a heterojunction structure in close contact. Compared with single Ag 3 PO 4 And LaCoO 3 And Ag 3 PO 4 The composite material prepared by the invention has obvious photoproduction electron-hole separation efficiency, photocatalytic activity and stability. The prepared composite photocatalyst is applied to treatment of tetracycline-containing refractory organic wastewater, has excellent removal rate of 89.27 percent, and has high recycling rate.)

1. The composite photocatalyst based on strontium doping is characterized by comprising the following components in percentage by mass (0.1-9): 1 La_1-xSr_xCoO₃And Ag₃PO₄And x is 0 to 0.9, wherein the La is_1-xSr_xCoO₃Is a bulk microstructure of oxygen-rich cavities, the Ag₃PO₄Is an irregular nanosphere structure, and the Ag₃PO₄Dispersed in the La_1-xSr_xCoO₃Forming a heterojunction structure.

2. A method for preparing a composite photocatalyst based on strontium doping according to claim 1, which comprises the following steps:

La_1-xSr_xCoO₃the preparation of (1): adding La (NO)₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Dissolving in deionized water, and fully mixing under the condition of magnetic stirring to obtain a mixed solution A;

adding citric acid and an organic additive into the mixed solution A, performing a first ultrasonic action, and fully dissolving to obtain a mixed solution B;

adjusting the pH value of the mixed solution B to 4-5, and then placing the mixed solution B in a water bath kettle at the temperature of 60-100 ℃ to continuously stir the mixed solution B to a mixture in a purple sol state;

placing the mixture in the purple sol state in an oven at 100-150 ℃ for drying for 10-20 h;

transferring the dried mixture into a crucible, placing the crucible in a muffle furnace, roasting for 1-4 h under the first temperature condition, adjusting the temperature to the second temperature condition, continuing roasting for 5-20 h, grinding the roasted mixture, and sieving with a 80-mesh sieve to obtain the La_{1- x}Sr_xCoO₃；

La_1-xSr_xCoO₃And Ag₃PO₄The preparation of the composite photocatalyst comprises the following steps: la to be prepared_1-xSr_xCoO₃Dispersing in ultrapure water, performing a second ultrasonic action, adding AgNO dissolved therein₃Stirring the aqueous solution for 10min to 50min, dropwise adding the aqueous solution dissolved with phosphate, stirring for 0.5h to 3h, centrifugally separating and recovering the precipitate obtained by the reaction, washing, vacuum drying, grinding and sieving the precipitate to obtain the La_1-xSr_xCoO₃And Ag₃PO₄The composite photocatalyst of (1).

3. The method for preparing the composite photocatalyst based on strontium doping according to claim 2, wherein the metal cations: citric acid: the molar ratio of the organic additive is 1 (0.5-2) to (0.5-3), wherein the mole number of the metal cation is La (NO) in the solution₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Total moles of metal cations.

4. The preparation method of the composite photocatalyst based on strontium doping, as claimed in claim 2, wherein the organic additive is one or more of disodium ethylenediamine tetraacetic acid, polyacrylamide and sodium alkyl benzene sulfonate.

5. The preparation method of the composite photocatalyst based on strontium doping according to claim 2, wherein the first temperature condition is 200-400 ℃.

6. The method for preparing the composite photocatalyst based on strontium doping according to claim 2, wherein the second temperature condition is 550-1000 ℃.

7. The preparation method of the composite photocatalyst based on strontium doping, as claimed in claim 2, wherein the phosphate is one of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate and dipotassium hydrogen phosphate.

8. The preparation method of the composite photocatalyst based on strontium doping according to claim 2, wherein the AgNO is₃Molar amount of (A) to said La_1-xSr_xCoO₃The molar weight ratio is (0.1-12) to 1.

9. The preparation method of the composite photocatalyst based on strontium doping according to claim 2, wherein the AgNO is₃The ratio of the molar amount of (a) to the molar amount of the phosphate is 9 (3-7).

10. Use of a composite photocatalyst based on strontium doping, wherein the composite photocatalyst based on strontium doping according to claim 1 is used for treating wastewater containing antibiotics.

Technical Field

The invention relates to the technical field of photocatalytic materials, in particular to a composite photocatalyst based on strontium doping and a preparation method and application thereof.

Background

The semiconductor photocatalysis technology is an environment-friendly high-tech technology with the greatest development prospect in the 21 st century, and has the advantages of high reaction efficiency, high mineralization rate of organic pollutants, wide source of catalyst raw materials, rich preparation method and the like. TiO 2₂The catalyst is the most widely studied catalyst so far, but the catalyst has a wide band gap and can only respond and absorb ultraviolet light. However, the ultraviolet light accounts for only about 4% and the visible light accounts for about 43% of the entire solar spectrum. Therefore, in order to fully utilize the visible light spectrum in the solar spectrum, the development of visible light response type photocatalyst is the current research hotspot. Silver phosphate (Ag) since 2010₃PO₄) Has been found to have excellent oxygen efficiency in photocatalytic decomposition of water₃PO₄The application of the photocatalyst is being studied more and more. Ag₃PO₄Has strong effect on visible light with wavelength less than 520nmStrongly absorbed and has excellent potential in the field of photocatalytic degradation of organic pollutants. However, Ag alone₃PO₄The photocatalyst system needs to have an electron sacrifice agent to show excellent photocatalytic activity. Otherwise, Ag₃PO₄Photocatalytic systems suffer from severe photo-corrosive effects, on the one hand due to Ag₃PO₄Has a certain slightly solubility (the solubility is 0.02g/L) in the solution; on the other hand, the Ag/Ag⁺Has an electrode potential higher than Ag₃PO₄The conduction band potential of the reaction system is that the photoproduction electrons of the reaction system are easy to react with Ag₃PO₄Ag in the lattice⁺Reduction to metallic Ag⁰. The photo-etching effect will gradually destroy Ag₃PO₄Thereby reducing Ag₃PO₄Photocatalytic activity of, ultimately leading to Ag₃PO₄The catalytic activity is lost. Based on the theory of heterojunction structure and doping, Ag with different structural properties can be obtained₃PO₄A composite photocatalyst is an improved Ag photocatalyst₃PO₄An effective means of photo-corrosiveness. At present, researches on a heterojunction structure catalyst and a doped catalyst are many, but researches on a synergistic effect between the heterojunction structure and the doped catalyst and an influence rule of the synergistic effect on catalytic activity and stability of the composite catalyst are less.

In summary, there still remains a need to solve the above problems in the field of photocatalytic material preparation.

Disclosure of Invention

Based on the fact, the Ag in the prior art is solved₃PO₄The invention provides a composite photocatalyst based on strontium doping, which solves the problems of easy recombination of photo-generated electrons and holes and poor photocatalytic activity and stability of a photocatalyst, and adopts the following specific technical scheme:

a composite photocatalyst based on strontium doping is prepared from the following components in parts by mass (0.1-9): 1 La_1-xSr_xCoO₃And Ag₃PO₄And x is 0 to 0.9, wherein the La is_1-xSr_xCoO₃Is rich inBulk microstructures containing oxygen vacancies, said Ag₃PO₄Is an irregular nanosphere structure, and the Ag₃PO₄Dispersed in the La_1-xSr_xCoO₃Forming a heterojunction structure.

In addition, the invention also provides a preparation method of the composite photocatalyst based on strontium doping, which comprises the following steps:

La_1-xSr_xCoO₃the preparation of (1): adding La (NO)₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Dissolving in deionized water, and fully mixing under the condition of magnetic stirring to obtain a mixed solution A;

adding citric acid and an organic additive into the mixed solution A, performing a first ultrasonic action, and fully dissolving to obtain a mixed solution B;

adjusting the pH value of the mixed solution B to 4-5 by using ammonia water, and then placing the mixed solution B in a water bath kettle at the temperature of 60-100 ℃ to continuously stir the mixed solution B to a mixture in a purple sol state;

placing the mixture in the purple sol state in an oven at 100-150 ℃ for drying for 10-20 h to obtain a dried mixture;

transferring the dried mixture into a crucible, placing the crucible in a muffle furnace, roasting for 1-4 h under the first temperature condition, adjusting the temperature to the second temperature condition, continuing roasting for 5-20 h, grinding and sieving with a 80-mesh sieve to obtain La_1-xSr_xCoO₃；

La_1-xSr_xCoO₃And Ag₃PO₄The preparation of the composite photocatalyst comprises the following steps: la to be prepared_1-xSr_xCoO₃Dispersing in ultrapure water, performing a second ultrasonic action, adding AgNO dissolved therein₃Stirring the aqueous solution for 10min to 50min, dropwise adding the aqueous solution dissolved with phosphate, stirring for 0.5h to 3h, centrifugally separating and recovering a precipitate obtained by the reaction, washing, vacuum drying, grinding and sieving the precipitate to obtain the La_1-xSr_xCoO₃And Ag₃PO₄The composite photocatalyst of (1).

Preferably, the metal cation: citric acid: the molar ratio of the organic additive is 1 (0.5-2) to (0.5-3), wherein the mole number of the metal cation is La (NO) in the solution₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Total moles of metal cations.

Preferably, the organic additive is one or more of disodium ethylene diamine tetraacetate, polyacrylamide and sodium alkyl benzene sulfonate.

Preferably, the first temperature condition is 200 ℃ to 400 ℃.

Preferably, the second temperature condition is 550 ℃ to 1000 ℃.

Preferably, the phosphate is one of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate and dipotassium hydrogen phosphate.

Preferably, the AgNO₃Molar amount of (A) to the La_1-xSr_xCoO₃The molar weight ratio is (0.1-12) to 1.

Preferably, the AgNO₃The ratio of the molar amount of (a) to the molar amount of the phosphate is 9 (3-7).

Preferably, the application of the composite photocatalyst based on strontium doping is also provided.

Preferably, the application is to apply the composite photocatalyst to the treatment of wastewater containing antibiotics.

The composite photocatalyst prepared in the scheme is based on strontium doping, namely La_1-xSr_xCoO₃And Ag₃PO₄Compared with single Ag₃PO₄Or LaCoO₃And Ag₃PO₄The composite material has better visible light absorption intensity, photocatalysis performance, light corrosion resistance and structural stability; in addition, Ag in the composite photocatalyst of the invention₃PO₄Dispersed in La_{1- x}Sr_xCoO₃The surface of the substrate forms a heterojunction structure, has higher electron-hole separation efficiency, and is suitable forThe antibiotic wastewater shows stronger catalytic degradation activity; and based on a composite photocatalyst doped with strontium, namely La_1-xSr_xCoO₃And Ag₃PO₄The composite material also has excellent recycling value.

Drawings

FIG. 1 shows La in example 1 of the present invention_0.1Sr_0.9CoO₃And Ag₃PO₄A Scanning Electron Microscope (SEM) image of the composite photocatalyst of (1);

FIG. 2 shows La in example 1 of the present invention_0.1Sr_0.9CoO₃And Ag₃PO₄The X-ray diffraction (XRD) spectrum of the composite photocatalyst is shown;

FIG. 3 shows La in example 1 of the present invention_0.1Sr_0.9CoO₃And Ag₃PO₄The fluorescence spectrum (PL) diagram of the composite photocatalyst of (1);

FIG. 4 shows La in example 1 of the present invention_0.1Sr_0.9CoO₃X-ray photoelectron spectroscopy (XPS, O1s) graph of (a);

FIG. 5 shows La in application test example 1 of the present invention_0.1Sr_0.9CoO₃And Ag₃PO₄A photocatalytic activity profile of the composite of (a);

FIG. 6 shows La of application test example 7 of the present invention_0.1Sr_0.9CoO₃And Ag₃PO₄The photocatalytic stability of the composite photocatalyst is shown schematically.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to embodiments thereof. It should be understood that the detailed description and specific examples, while indicating the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

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. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The semiconductor material can generate electron-hole pairs under the condition of illumination excitation, and the photogenerated electrons and holes can migrate to the surface of the catalyst, so that a series of active species are induced to be generated, or the photogenerated electrons and holes directly participate in the degradation of pollutants. However, after the photo-generated electron and hole pairs are generated, a part of the photo-generated electron and hole pairs are compounded in the catalyst, and a part of the photo-generated electron and hole pairs are compounded after the photo-generated electron and hole pairs are transferred to the surface of the catalyst, so that the effective photo-generated electron and hole amount of a photo-catalytic reaction system is less, and the catalytic activity of the photocatalyst is greatly reduced.

The semiconductor heterojunction has excellent performances in the aspects of rectification, photovoltaic characteristics, optical waveguide effect and the like, so that the separation capability of photoinduced charges (electrons and holes) of the heterojunction is far higher than that of a single semiconductor. In addition, the doped semiconductor has the advantages of effectively adjusting the band gap of the semiconductor, changing the band structure of the semiconductor, widening the photoresponse range and the like due to the introduction of the impurity energy level into the catalyst. Therefore, the invention builds the heterojunction LaCoO based on two concepts of heterojunction construction and doping₃And Ag₃PO₄Based on the composite material, Sr is introduced into LaCoO₃In the crystal structure of (A) constitutes a doped-heterojunction type catalyst, i.e. La_1-xSr_xCoO₃And Ag₃PO₄Thereby fully exerting the advantages of the two materials to improve the photocatalytic activity and stability of the composite material.

Specifically, the invention provides a composite photocatalyst based on strontium doping, and the composite photocatalyst is La_{1- x}Sr_xCoO₃And Ag₃PO₄The composite photocatalyst is prepared from the composite material, and La in the composite photocatalyst based on strontium doping_1-xSr_xCoO₃Bulk microstructures, Ag, rich in oxygen vacancies₃PO₄Is an irregular nanosphere structure, and Ag₃PO₄Dispersed in La_1-xSr_xCoO₃Forming a heterojunction structure.

Sr⁺Will replace LaCoO₃La in crystal lattice³⁺Form La_1-xSr_xCoO₃The doping system can change the self-spinning state of Co ions and change the valence of Co ions in the substitution process, thereby regulating the band gap structure of the compound and leading La to be in charge of_{1- x}Sr_xCoO₃Exhibit good light absorption properties.

In one embodiment, the La_1-xSr_xCoO₃And Ag₃PO₄X in the composite photocatalyst is 0-0.9.

In one embodiment, the La_1-xSr_xCoO₃And Ag₃PO₄The x in the composite photocatalyst is 0.01-0.7.

In one embodiment, the La_1-xSr_xCoO₃And Ag₃PO₄The x in the composite photocatalyst is 0.03-0.5.

In one embodiment, the La_1-xSr_xCoO₃And Ag₃PO₄The x in the composite photocatalyst is 0.05-0.3.

In one embodiment, the La_1-xSr_xCoO₃And Ag₃PO₄The x in the composite photocatalyst is 0.08-0.2.

In one embodiment, the La_1-xSr_xCoO₃And Ag₃PO₄X in the composite photocatalyst of (1) is 0.1.

In one embodiment, the La_1-xSr_xCoO₃With said Ag₃PO₄The mass ratio of (0.1-9): 1.

in one embodiment, the La_1-xSr_xCoO₃With said Ag₃PO₄The mass ratio of (0.5-8): 1.

in one embodiment, the La_1-xSr_xCoO₃With said Ag₃PO₄The mass ratio of (1-7): 1.

in one embodiment, the La_1-xSr_xCoO₃With said Ag₃PO₄The mass ratio of (3-5): 1.

in one embodiment, the La_1-xSr_xCoO₃With said Ag₃PO₄The mass ratio of (A) to (B) is 4: 1.

In one embodiment, the invention also provides a preparation method of the composite photocatalyst based on strontium doping, which comprises the following steps:

(1)La_1-xSr_xCoO₃the preparation of (1): preparing La with different compositions by adopting sol-gel method_1-xSr_xCoO₃. Adding La (NO)₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Dissolving in deionized water, and fully mixing under the condition of magnetic stirring to obtain a mixed solution A;

adding citric acid and an organic additive into the mixed solution A, performing a first ultrasonic action, and fully dissolving to obtain a mixed solution B;

adjusting the pH value of the mixed solution B to 4-5 by using ammonia water, and then placing the mixed solution B in a water bath kettle at the temperature of 60-100 ℃ to continuously stir the mixed solution B to a mixture in a purple sol state;

placing the mixture in the purple sol state in an oven at 100-150 ℃ for drying for 10-20 h to obtain a dried mixture;

transferring the dried mixture into a crucible, placing the crucible in a muffle furnace, roasting for 1-4 h under the first temperature condition, adjusting the temperature to the second temperature condition, continuously roasting for 5-20 h, grinding after roasting, and sieving with a 80-mesh sieve to obtain the La_{1- x}Sr_xCoO₃；

(2)La_1-xSr_xCoO₃And Ag₃PO₄The preparation of the composite photocatalyst comprises the following steps: is prepared by an in-situ precipitation method. Mixing the La prepared in the step (1)_1-xSr_xCoO₃Dispersing in ultrapure water, adding AgNO dissolved therein after the second ultrasonic action₃Stirring the aqueous solution for 10min to 50min, dropwise adding the aqueous solution dissolved with phosphate, stirring for 0.5h to 3h, centrifugally separating and recovering a precipitate obtained by the reaction, washing, vacuum drying, grinding and sieving the precipitate to obtain the La_{1- x}Sr_xCoO₃And Ag₃PO₄The composite photocatalyst of (1).

In one embodiment, the molar ratio of the metal cation, the citric acid and the organic additive is 1: (0.5-2): (0.5-3), wherein the mole number of the metal cation is La (NO) in the solution₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Total moles of metal cations.

In one embodiment, the molar ratio of the metal cation, the citric acid and the organic additive is 1: (0.6-1.5): (1-2), wherein the mole number of the metal cation is La (NO) in the solution₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Total moles of metal cations.

In one embodiment, the molar ratio of the metal cation, the citric acid and the organic additive is 1: (0.8-1.2): (1.2-1.8), wherein the mole number of the metal cation is La (NO) in the solution₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Total moles of metal cations.

In one embodiment, the molar ratio of the metal cation, the citric acid and the organic additive is 1: 1: 1.5, wherein the molar number of the metal cation is La (NO) in the solution₃)₃·6H₂O、Co(NO₃)₃·6H₂O and Sr (NO)₃)₂Total moles of metal cations.

In one embodiment, the organic additive is one or more of disodium ethylene diamine tetraacetate, polyacrylamide and sodium alkyl benzene sulfonate.

In one embodiment, the power of the first ultrasonic action is 200W-400W, and the time of the first ultrasonic action is 20min-60 min.

In one embodiment, the power of the first ultrasonic action is 250W-350W, and the time of the first ultrasonic action is 30min-50 min.

In one embodiment, the power of the first ultrasonic action is 300W, and the time of the first ultrasonic action is 40 min.

In one embodiment, the pH value of the mixed solution B is adjusted to 4.5.

In one embodiment, the pH adjustment is performed using ammonia.

In one embodiment, the temperature in the water bath is 70 ℃ to 100 ℃.

In one embodiment, the temperature in the water bath is 80 ℃.

In one embodiment, the drying temperature in the oven is 110-130 ℃, and the drying time is 12-18 h.

In one embodiment, the temperature for drying in the oven is 120 ℃ and the drying time is 16 h.

In one embodiment, the first temperature condition is 200 ℃ to 400 ℃.

In one embodiment, the first temperature condition is 250 ℃ to 350 ℃.

In one embodiment, the first temperature condition is 300 ℃.

In one embodiment, the first temperature condition is calcination for 1h to 4 h.

In one embodiment, the first temperature condition is calcination for 1.5h to 3 h.

In one embodiment, the first temperature condition is calcination for 2 h.

In one embodiment, the second temperature condition is 550 ℃ to 1000 ℃.

In one embodiment, the second temperature condition is 600 ℃ to 900 ℃.

In one embodiment, the second temperature condition is 650 ℃ to 800 ℃.

In one embodiment, the second temperature condition is 700 ℃.

In one embodiment, the second temperature condition is for 5h to 20 h.

In one embodiment, the second temperature condition is calcination for 6h to 14 h.

In one embodiment, the second temperature condition is calcination for 7h to 10 h.

In one embodiment, the second temperature condition is for 8 hours.

In one embodiment, the phosphate is one of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate, and dipotassium hydrogen phosphate.

In one embodiment, the AgNO₃Molar amount of (A) to the La_1-xSr_xCoO₃The molar weight ratio is (0.1-12) to 1.

In one embodiment, the AgNO₃The ratio of the molar amount of (a) to the molar amount of the phosphate is 9 (3-7).

In one embodiment, the amount of ultrapure water used is 0.01mol La per unit volume_1-xSr_xCoO₃40mL was used.

In one embodiment, the power of the second ultrasonic action is 200W-400W, and the time of the second ultrasonic action is 10min-50 min.

In one embodiment, the power of the second ultrasonic action is 250W-350W, and the time of the second ultrasonic action is 20min-40 min.

In one embodiment, the power of the second ultrasonic action is 300W, and the time of the second ultrasonic action is 30 min.

In one embodiment, the washing is repeated ultrasonic washing with absolute ethyl alcohol and ultrapure water.

In one embodiment, the temperature of the vacuum drying is 40-80 ℃, and the time of the vacuum drying is 6-18 h.

In one embodiment, the temperature of the vacuum drying is 60 ℃, and the time of the vacuum drying is 12 h.

In one embodiment, the screening is through a 60 mesh to 120 mesh screen.

In one embodiment, the screening is through an 80 mesh screen.

In one embodiment, the invention also provides application of the composite photocatalyst based on strontium doping.

In one embodiment, the application is to apply the composite photocatalyst to treatment of wastewater containing antibiotics.

In one embodiment, the antibiotic is tetracycline.

In one embodiment, the application method is to add the composite photocatalyst based on strontium doping, namely La, into the wastewater containing the antibiotics_1-xSr_xCoO₃And Ag₃PO₄The composite material is subjected to dark adsorption reaction, and visible light illumination is performed after the balance is achieved; in the above process, samples are taken at regular intervals to determine the antibiotic concentration in the wastewater.

In one embodiment, the application is La_1-xSr_xCoO₃And Ag₃PO₄The amount of the composite material is as follows: antibiotics and La contained in the wastewater_1-xSr_xCoO₃And Ag₃PO₄The mass ratio of the composite material is 1 (10-200).

In one embodiment, the application is La_1-xSr_xCoO₃And Ag₃PO₄The amount of the composite material is as follows: antibiotics and La contained in the wastewater_1-xSr_xCoO₃And Ag₃PO₄The mass ratio of the composite material is 1 (50-150).

In one embodiment, the application is La_1-xSr_xCoO₃And Ag₃PO₄The amount of the composite material is as follows: antibiotics and La contained in the wastewater_1-xSr_xCoO₃And Ag₃PO₄The mass ratio of the composite material (2) is 1: 100.

The invention utilizes a sol-gel method to prepare oxygen-enriched cavity La based on strontium doping_1-xSr_xCoO₃And then adopting an in-situ precipitation method to prepare the oxygen-enriched hole visible light composite photocatalyst which is based on the doping of strontium and has different components, namely La_1-xSr_xCoO₃And Ag₃PO₄The composite material of (1). Compared with single Ag₃PO₄And LaCoO₃And Ag₃PO₄The composite material prepared by the invention has obvious visible light absorption intensity, photocatalytic performance and photo-corrosion resistance.

The present invention will be described in detail below with reference to examples.

Example 1

A preparation method of a composite photocatalyst based on strontium doping comprises the following steps:

firstly, preparing oxygen-enriched cavity La based on strontium doping by adopting a sol-gel method_0.1Sr_0.9CoO₃0.01mol of Co (NO) was weighed out separately₃)₃·6H₂O, 0.001mol of La (NO)₃)₃·6H₂O and 0.009mol of Sr (NO)₃)₂Dissolving in deionized water, and fully mixing under the condition of magnetic stirring to obtain a mixed solution A;

and then according to the metal cation: citric acid: the molar ratio of the ethylene diamine tetraacetic acid disodium is 1: 1: 1.5, accurately weighing 0.020mol of citric acid and 0.030mol of disodium ethylene diamine tetraacetate, adding the citric acid and the disodium ethylene diamine tetraacetate into the mixed solution A, and carrying out ultrasonic treatment in an ultrasonic oscillator with the power of 300W for 40min to fully dissolve the citric acid and the disodium ethylene diamine tetraacetate to obtain a mixed solution B;

then adjusting the pH value of the mixed solution B to 4.5 by using ammonia water, placing the mixed solution B in a water bath kettle at the temperature of 80 ℃, continuously stirring the mixed solution B to a mixture in a purple sol state, and then drying the mixture in a drying oven at the temperature of 120 ℃ for 16 hours;

transferring the dried mixture into a crucible, placing the crucible into a muffle furnace, roasting the mixture for 2 hours at 300 ℃, then heating the muffle furnace to 700 ℃, and continuously roasting the mixture for 8 hoursGrinding the roasted mixture and sieving the ground mixture with a 80-mesh sieve to obtain the La prepared under the condition that the disodium ethylene diamine tetraacetate is used as an additive_0.1Sr_0.9CoO₃。

Further adopting an in-situ precipitation method to prepare La_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material of (a): accurately weighing 1mmol of La prepared in the step (1)_0.1Sr_0.9CoO₃Dispersing in 40mL of ultrapure water, sonicating in a 300W ultrasonic oscillator for 30min, adding 10mL of solution with 0.287mmol of AgNO₃Stirring the aqueous solution for 60min, and finally dropwise adding 20mL of Na dissolved with 0.191mmol₂HPO₄·12H₂Stirring the O solution for 1h, centrifugally separating and recovering a solid precipitate obtained by the reaction through a centrifugal machine at the rotating speed of 6000r/min, repeatedly ultrasonically washing the solid precipitate with absolute ethyl alcohol and ultrapure water, drying for 12h in a vacuum drying oven at the temperature of 60 ℃, grinding and sieving with a 80-mesh sieve to obtain the La solution with the mass ratio of 4:1_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material of (1).

La obtained in example 1_0.1Sr_0.9CoO₃And Ag₃PO₄The SEM, XRD, PL characterization results of the composite material of (a) are shown in fig. 1, fig. 2 and fig. 3, respectively. LaCoO₃And La_0.1Sr_0.9CoO₃XPS (O1s) of (A) is shown in FIG. 4. As can be seen from SEM, La in the composite photocatalyst based on strontium doping_0.1Sr_0.9CoO₃In the form of micron-sized blocks of Ag₃PO₄Is an irregular nanosphere structure, and Ag₃PO₄Dispersed in La_1-xSr_xCoO₃The surface of (a) in close contact with a structure constituting a heterojunction; and XRD analysis proves that La is adopted_0.1Sr_0.9CoO₃And Ag₃PO₄The components of the composite photocatalyst; XPS (O1s) analysis showed that La based on strontium doping_0.1Sr_0.9CoO₃Has a richer oxygen vacancy; PL analysis showed La_0.1Sr_0.9CoO₃/Ag₃PO₄Has lower fluorescence intensity and represents complexThe catalyst system has lower photoproduction electron-hole recombination rate.

Application test example 1:

the composite photocatalyst is applied to the removal of tetracycline in wastewater, and relevant performance tests are carried out: 1g of the composite photocatalyst based on strontium doping prepared in example 1, namely La with the mass ratio of 4:1, is added into 1L of 10mg/L tetracycline solution_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material is subjected to dark adsorption reaction for 30min to reach adsorption equilibrium, then is subjected to photocatalytic reaction for 180min under the condition of 300W xenon lamp irradiation, solid-liquid separation is performed through centrifugation after the experiment is finished, the residual concentration of tetracycline in the supernatant is measured, and the photocatalytic performance of the composite photocatalyst based on strontium doping and silver phosphate is shown in figure 5. According to the test result, after the light is irradiated for 180min, the La with the mass ratio of 4:1 based on the doping of the strontium is obtained_0.1Sr_0.9CoO₃And Ag₃PO₄The removal efficiency of the composite material on the tetracycline is 89.27%, which is far higher than that of a single silver phosphate photocatalytic system (65.53%).

Example 2

A preparation method of a composite photocatalyst based on strontium doping comprises the following steps:

(1)、La_0.1Sr_0.9CoO₃was prepared as in example 1.

(2) And then further adopting an in-situ precipitation method to prepare La_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material (1) is prepared by accurately weighing 1mmol of La prepared in the step (1)_0.1Sr_0.9CoO₃Dispersing in 40mL of ultrapure water, sonicating in a 300W ultrasonic oscillator for 30min, adding 10mL of solution with 0.366mol of AgNO₃Stirring the aqueous solution for 60min, and finally dropwise adding 20mL of Na dissolved with 0.257mol₂HPO₄·12H₂Stirring O solution for 1h, centrifuging at 6000r/min by use of a centrifuge to recover solid precipitate, repeatedly ultrasonically washing the solid precipitate with anhydrous ethanol and ultrapure water, and drying in a vacuum drying oven at 60 deg.CDrying for 12h, grinding, and sieving with 80 mesh sieve to obtain La with mass ratio of 0.67:1_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material of (1).

Application test example 2:

the composite photocatalyst is applied to the removal of tetracycline in wastewater, and relevant performance tests are carried out: 1g of the composite photocatalyst prepared in the example 2, namely La with the mass ratio of 0.67:1, is added into 1L of 10mg/L tetracycline solution_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material is subjected to dark adsorption reaction for 30min to reach adsorption equilibrium, then subjected to photocatalytic reaction for 180min under the condition of 300W xenon lamp irradiation, subjected to solid-liquid separation by centrifugation after the experiment is finished, and the residual concentration of tetracycline in the supernatant is measured. According to the test result, after the light is irradiated for 180min, the La with the mass ratio of 0.67:1 based on the strontium doping_0.1Sr_0.9CoO₃And Ag₃PO₄The tetracycline removal efficiency of the composite material of (a) was 84.81%.

Example 3:

a preparation method of a composite photocatalyst based on strontium doping comprises the following steps:

(1) firstly, preparing La based on strontium doping by adopting a sol-gel method_0.5Sr_0.5CoO₃: 9mmol of Co (NO) were weighed out separately₃)₃·6H₂O, 4.54mmol of La (NO)₃)₃·6H₂O and 4.54mmol of Sr (NO)₃)₂Dissolving in deionized water, and mixing under magnetic stirring; and then according to the metal cation: citric acid: the molar ratio of the ethylene diamine tetraacetic acid disodium is 1: 1: 1.5, accurately weighing citric acid (0.018mol) and disodium ethylene diamine tetraacetate (0.027mol), adding the citric acid and the disodium ethylene diamine tetraacetate into the solution, and carrying out ultrasonic treatment in an ultrasonic oscillator with the power of 300W for 40min to fully dissolve the citric acid and the disodium ethylene diamine tetraacetate. Then, the pH value of the solution was adjusted to 4.5 with ammonia water, and then the solution was continuously stirred in a water bath at 80 ℃ to a purple sol state, and then dried in an oven at 120 ℃ for 16 hours. Transferring the dried sample into a crucible, placing the crucible into a muffle furnace, roasting the sample for 2 hours at 300 ℃, then heating the muffle furnace to 700 ℃, and continuously roasting the sample for 8 hours. Grinding the roasted sample, sieving with 80 mesh sieve, labeling, bagging, and storing to obtain La-containing disodium edetate as additive_0.5Sr_0.5CoO₃。

(2) And then further adopting an in-situ precipitation method to prepare La_0.5Sr_0.5CoO₃And Ag₃PO₄The composite material of (a): accurately weighing 1mmol of La prepared in the step (1)_0.5Sr_0.5CoO₃Dispersing in 40mL of ultrapure water, sonicating in a 300W ultrasonic oscillator for 30min, adding 10mL of solution with 0.287mmol of AgNO₃Stirring the aqueous solution for 60min, and finally dropwise adding 20mL of Na dissolved with 0.191mmol₂HPO₄·12H₂Stirring the O solution for 1h, centrifugally separating and recovering a solid precipitate obtained by the reaction through a centrifugal machine at the rotating speed of 6000r/min, repeatedly ultrasonically washing the solid precipitate with absolute ethyl alcohol and ultrapure water, drying for 12h in a vacuum drying oven at the temperature of 60 ℃, grinding and sieving with a 80-mesh sieve to obtain the La solution with the mass ratio of 4:1_0.5Sr_0.5CoO₃And Ag₃PO₄The composite material of (1).

Application test example 3:

the composite photocatalyst is applied to the removal of tetracycline in wastewater, and relevant performance tests are carried out: 1g of the composite photocatalyst prepared in the example 3, namely La with the mass ratio of 4:1, is added into 1L of 10mg/L tetracycline solution_0.5Sr_0.5CoO₃And Ag₃PO₄The composite material is subjected to dark adsorption reaction for 30min to reach adsorption equilibrium, then subjected to photocatalytic reaction for 180min under the condition of 300W xenon lamp irradiation, subjected to solid-liquid separation by centrifugation after the experiment is finished, and the residual concentration of tetracycline in the supernatant is measured. According to the test result, after the light is irradiated for 180min, the La with the mass ratio of 4:1 based on the doping of the strontium is obtained_0.5Sr_0.5CoO₃And Ag₃PO₄The tetracycline removal efficiency of the composite material of (a) was 78.56%.

Example 4

A preparation method of a composite photocatalyst based on strontium doping comprises the following steps:

(1) firstly, preparing oxygen-enriched cavity La based on strontium doping by adopting a sol-gel method_0.1Sr_0.9CoO₃0.01mol of Co (NO) was weighed out separately₃)₃·6H₂O, 0.001mol of La (NO)₃)₃·6H₂O and 0.009mol of Sr (NO)₃)₂Dissolving in deionized water, and mixing under magnetic stirring; and then according to the metal cation: citric acid: the molar ratio of the sodium alkyl benzene sulfonate is 1: 1: 1.5, accurately weighing citric acid (0.020mol) and sodium alkyl benzene sulfonate (0.030mol), adding the citric acid and the sodium alkyl benzene sulfonate into the solution, and carrying out ultrasonic treatment in an ultrasonic oscillator with the power of 300W for 40min to fully dissolve the citric acid and the sodium alkyl benzene sulfonate. Then, the pH value of the solution was adjusted to 4.5 with ammonia water, and then the solution was continuously stirred in a water bath at 80 ℃ to a purple sol state, and then dried in an oven at 120 ℃ for 16 hours. And transferring the dried sample into a crucible, placing the crucible into a muffle furnace, roasting the sample for 2 hours at 300 ℃, then heating the muffle furnace to 700 ℃, and continuing to roast the sample for 8 hours. Grinding the roasted sample, sieving with 80 mesh sieve, labeling, bagging, and storing to obtain La product with sodium alkyl benzene sulfonate as additive_0.1Sr_0.9CoO₃。

(2) And then further adopting an in-situ precipitation method to prepare La_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material of (a): accurately weighing 1mmol of La prepared in the step (1)_0.1Sr_0.9CoO₃Dispersing in 40mL of ultrapure water, sonicating in a 300W ultrasonic oscillator for 30min, adding 10mL of solution with 0.287mmol of AgNO₃Stirring the aqueous solution for 60min, and finally dropwise adding 20mL of Na dissolved with 0.191mmol₂HPO₄·12H₂Stirring O solution for 1h, centrifuging by a centrifuge with the rotation speed of 6000r/min to recover solid precipitate obtained by reaction, repeatedly ultrasonically washing the solid precipitate with absolute ethanol and ultrapure water, drying in a vacuum drying oven at 60 ℃ for 12h, grinding, and sieving with a 80-mesh sieve to obtain sodium alkyl benzene sulfonate as an additive, wherein the La is La in a mass ratio of 4:1_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material of (1).

Application test example 4:

the composite photocatalyst is applied to the removal of tetracycline in wastewater, and relevant performance tests are carried out: 1g of the composite photocatalyst prepared in the example 4, namely sodium alkyl benzene sulfonate serving as an additive, is added into 1L of 10mg/L tetracycline solution, and the mass ratio of the composite photocatalyst to the additive is 4:1_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material is subjected to dark adsorption reaction for 30min to reach adsorption equilibrium, then subjected to photocatalytic reaction for 180min under the condition of 300W xenon lamp irradiation, subjected to solid-liquid separation by centrifugation after the experiment is finished, and the residual concentration of tetracycline in the supernatant is measured. According to the test results, after the illumination for 180min, the additive is based on strontium-doped sodium alkyl benzene sulfonate, and the mass ratio of La to Na is 4:1_0.1Sr_0.9CoO₃And Ag₃PO₄The tetracycline removal efficiency of the composite material of (1) was 73.58%.

Application test example 5:

the composite photocatalyst is applied to the removal of tetracycline in wastewater, and relevant performance tests are carried out: 1g of the composite photocatalyst prepared in the example 1, namely La with the mass ratio of 4:1, is added into 1L of 30mg/L tetracycline solution_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material is subjected to dark adsorption reaction for 30min to reach adsorption equilibrium, then subjected to photocatalytic reaction for 180min under the condition of 300W xenon lamp irradiation, subjected to solid-liquid separation by centrifugation after the experiment is finished, and the residual concentration of tetracycline in the supernatant is measured. According to the test result, after the light is irradiated for 180min, the La with the mass ratio of 4:1 based on the doping of the strontium is obtained_0.1Sr_0.9CoO₃And Ag₃PO₄The tetracycline removal efficiency of the composite material of (a) was 74.62%.

Application test example 6:

the composite photocatalyst is applied to the removal of tetracycline in wastewater, and relevant performance tests are carried out: 0.5g of the composite photocatalyst prepared in the example 1, namely La with the mass ratio of 4:1, is added into 1L of 10mg/L antibiotic solution_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material is firstly subjected to dark adsorption reaction for 30min to reach adsorption balance,and carrying out photocatalytic reaction for 180min under the condition of 300W xenon lamp irradiation, carrying out solid-liquid separation by centrifugation after the experiment is finished, and measuring the residual concentration of tetracycline in the supernatant. According to the test result, after the light is irradiated for 180min, the La with the mass ratio of 4:1 based on the doping of the strontium is obtained_0.1Sr_0.9CoO₃And Ag₃PO₄The tetracycline removal efficiency of the composite material of (a) was 81.92%.

Application test example 7:

the composite photocatalyst is applied to the removal of tetracycline in wastewater, and relevant performance tests are carried out: 1g of the composite photocatalyst prepared in the example 1, namely La with the mass ratio of 4:1, is added into 1L of 10mg/L tetracycline solution_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material is subjected to dark adsorption reaction for 30min to reach adsorption equilibrium, then subjected to photocatalytic reaction for 180min under the condition of 300W xenon lamp irradiation, subjected to solid-liquid separation by centrifugation after the experiment is finished, and the residual concentration of tetracycline in the supernatant is measured. The recovered visible light composite photocatalyst based on strontium doping is La with the mass ratio of 4:1_0.1Sr_0.9CoO₃And Ag₃PO₄The composite material is washed by ultrapure water for a plurality of times, dried in a vacuum drying oven at 60 ℃, ground, sieved by a sieve with 80 meshes, and applied to tetracycline wastewater treatment again, the treatment process is the same as the above, the recycling efficiency is shown in figure 6, and the test result shows that the strontium doping-based La with the mass ratio of 4:1 is adopted_0.1Sr_0.9CoO₃And Ag₃PO₄When the composite material is recycled for the sixth time, the tetracycline removal efficiency is still 81.04%.

In conclusion, the composite photocatalyst based on strontium doping, and the preparation method and the application thereof provided by the invention have the advantages that the composite photocatalyst prepared by the invention has obvious visible light absorption intensity, photocatalytic performance and photo-corrosion resistance. In addition, the composite photocatalyst can effectively degrade antibiotics in the organic wastewater, is high in removal rate and has a recycling value.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.