Bismuth phosphotungstate as well as preparation method and application thereof

Abstract

The invention discloses bismuth phosphotungstate as well as a preparation method and application thereof, and belongs to the technical field of photocatalytic materials. According to the preparation method, tungstate and hydrophosphate are taken as raw materials, phosphotungstic acid with relatively high purity is obtained after acidification under an acidic condition, then phosphotungstic acid reacts with bismuth salt, finally, the bismuth phosphotungstate material with relatively high purity is prepared, and the bismuth phosphotungstate material has a special electronic structure, so that the bismuth phosphotungstate material has relatively good oxidation-reduction capability and can be used for preparing the bismuth phosphotungstate material with relatively high purity. Under the condition of illumination, absorbed light is used as energy, and organic wastes can be converted into carbon dioxide and water, so that green and efficient degradation of the organic wastes is realized; in addition, the preparation process is simple, the used raw materials are cheap and easy to obtain, industrial large-scale production is facilitated, and the method has a good application prospect in efficient degradation of organic wastes.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalytic materials, and in particular relates to bismuth phosphotungstate and a preparation method and application thereof. Background Art

[0002] In recent years, environmental protection has received more and more attention. Among them, the treatment of dye wastewater has always been a problem that has troubled people. Photocatalysis can directly use sunlight to degrade organic dyes in water, which is a very green and environmentally friendly method.

[0003] Due to its strong absorption capacity for visible light and its special electronic structure, a series of special materials prepared from bismuth have excellent performance, especially in photocatalytic degradation. However, existing photocatalysts have problems such as difficult preparation and low catalytic activity.

[0004] In view of this, it is necessary to develop new bismuth-based photocatalysts with simple preparation and high catalytic activity to address the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of the present invention is to provide bismuth phosphotungstate and its preparation method and application, so as to solve the problems of difficult preparation and low catalytic activity of existing photocatalysts.

[0006] In a first aspect, the present invention provides a method for preparing bismuth phosphotungstate, comprising the following steps: S1, mixing tungstate and hydrogen phosphate and dissolving the mixture in a first solvent, then adding acid solution for acidification reaction, and extracting, separating, and purifying the obtained product to obtain phosphotungstic acid; S2, dissolving the phosphotungstic acid in a second solvent to obtain a phosphotungstic acid solution; adding a bismuth source to the acid solution and dissolving it to obtain a bismuth salt solution; mixing the phosphotungstic acid solution and the bismuth salt solution and reacting them, and separating and purifying the obtained product to obtain bismuth phosphotungstate; wherein, in step S2, the bismuth source includes bismuth trioxide.

[0007] In the present invention, tungstate and hydrogen phosphate are first used as raw materials, and after acidification under acidic conditions, high-purity phosphotungstic acid is obtained. Then, the phosphotungstic acid is reacted with a bismuth salt to finally prepare a high-purity bismuth phosphotungstate material. The bismuth phosphotungstate material has a special electronic structure and therefore has good redox ability. Under light conditions, it absorbs light as energy and can convert organic waste into carbon dioxide and water, thereby achieving green and efficient degradation of organic waste. In addition, the preparation process of the present invention is simple, the raw materials used are cheap and easily available, and it is convenient for industrial large-scale production, and has good application prospects in the efficient degradation of organic waste.

[0008] In some embodiments, in step S1, the molar ratio of tungstate to hydrogen phosphate is 1:(0.2-0.4), the tungstate includes sodium tungstate dihydrate, and the hydrogen phosphate includes disodium hydrogen phosphate dodecahydrate.

[0009] In some embodiments, in step S1, the mass ratio of tungstate to the first solvent is 1:(1.4-1.6), and the first solvent includes water.

[0010] In some embodiments, in step S1, the molar ratio of tungstate to acid is 1:(3-6), and the acid includes hydrochloric acid solution.

[0011] In some embodiments, in step S1, the acidification reaction temperature is 90-110° C. and the time is 2-4 hours; the extraction, separation and purification specifically includes: extraction, separation and purification using an organic solvent; wherein the organic solvent is selected from at least one of methyl tert-butyl ether and diethyl ether.

[0012] In some embodiments, in step S2, the molar ratio of phosphotungstic acid to the bismuth source is 1:(1-2), and the second solvent includes water.

[0013] In some embodiments, in step S2, the molar ratio of the bismuth source to the acid solution is 1:(6-9), and the acid solution includes a hydrochloric acid solution.

[0014] In some embodiments, in step S2, the reaction temperature is 30-50°C and the reaction time is 1-3h; the separation and purification specifically includes: separation and purification using reduced pressure concentration; wherein the temperature of reduced pressure concentration is 90°C-110°C.

[0015] In a second aspect, the present invention provides bismuth phosphotungstate, which is prepared by any of the above preparation methods.

[0016] In a third aspect, the present invention provides the use of the above-mentioned bismuth phosphotungstate in the photocatalytic degradation of organic dyes.

[0017] In some embodiments, the organic dye includes at least one of methyl orange, methylene blue, and rhodamine B.

[0018] The beneficial effects of the present invention are as follows: different from the prior art, the present invention uses tungstate and hydrogen phosphate as raw materials, obtains high-purity phosphotungstic acid after acidification under acidic conditions, and then reacts the phosphotungstic acid with a bismuth salt to finally prepare a high-purity phosphotungstate material. The bismuth phosphotungstate material has a special electronic structure, and therefore has good redox ability. Under light conditions, it absorbs light as energy and can convert organic waste into carbon dioxide and water, thereby realizing green and efficient degradation of organic waste. In addition, the preparation process of the present invention is simple, the raw materials used are cheap and easily available, and it is convenient for industrial large-scale production, and has good application prospects in the efficient degradation of organic waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a flow chart of the preparation method of bismuth phosphotungstate of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] For experimental methods in the examples where specific conditions are not specified, generally conventional conditions and conditions described in the manual or conditions recommended by the manufacturer were followed. The general equipment, materials, reagents, etc. used were all commercially available unless otherwise specified.

[0022] Currently, existing photocatalysts have problems such as difficulty in preparation and low catalytic activity.

[0023] In order to solve the problems of difficult preparation and low catalytic activity of existing photocatalysts, the present invention provides bismuth phosphotungstate and its preparation method and application.

[0024] In a first aspect, the present invention provides a method for preparing bismuth phosphotungstate, comprising the following steps: S1, mixing tungstate and hydrogen phosphate and dissolving the mixture in a first solvent, then adding acid solution for acidification reaction, and extracting, separating, and purifying the obtained product to obtain phosphotungstic acid; S2, dissolving the phosphotungstic acid in a second solvent to obtain a phosphotungstic acid solution; adding a bismuth source to the acid solution and dissolving it to obtain a bismuth salt solution; mixing the phosphotungstic acid solution and the bismuth salt solution and reacting them, and separating and purifying the obtained product to obtain bismuth phosphotungstate; wherein, in step S2, the bismuth source includes bismuth trioxide.

[0025] In the preparation method of bismuth phosphotungstate provided by the present invention, tungstate and hydrogen phosphate are first used as raw materials, and after acidification under acidic conditions, phosphotungstic acid with high purity is obtained. Then, the phosphotungstic acid is reacted with a bismuth salt to finally prepare a bismuth phosphotungstate material with high purity. The bismuth phosphotungstate material has a special electronic structure and therefore has good redox ability. Under illumination, it absorbs light as energy and can convert organic waste into carbon dioxide and water, thereby achieving green and efficient degradation of organic waste. In addition, the preparation process of the present invention is simple, the raw materials used are cheap and easily available, and it is convenient for industrial large-scale production, and has good application prospects in the efficient degradation of organic waste.

[0026] In some embodiments, in step S1, the molar ratio of tungstate to hydrogen phosphate is 1:(0.2-0.4), for example, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4 or other ratios within this range; the tungstate includes sodium tungstate dihydrate, and the hydrogen phosphate includes disodium hydrogen phosphate dodecahydrate.

[0027] In the present invention, by controlling the molar ratio of tungstate to hydrogen phosphate within a specific range, the two can be fully reacted to avoid the generation of impurities.

[0028] It is understood that the tungstate and hydrogen phosphate salts can be selected from conventional tungstates and hydrogen phosphate salts in the prior art according to actual use needs, as long as they can provide tungstate and hydrogen phosphate. In the present invention, the tungstate salt preferably includes sodium tungstate dihydrate, and the hydrogen phosphate salt preferably includes disodium hydrogen phosphate dodecahydrate.

[0029] In some embodiments, in step S1, the mass ratio of tungstate to the first solvent is 1:(1.4-1.6), for example, 1:1.4, 1:1.45, 1:1.5, 1:1.55, 1:1.6 or other ratios within this range; the first solvent includes water.

[0030] It is understandable that the mass ratio of tungstate to the first solvent and the first solvent can be conventionally adjusted according to actual use needs, as long as the tungstate can be completely dissolved. In the present invention, the mass ratio of tungstate to the first solvent is preferably 1: (1.4-1.6), and the first solvent preferably includes water.

[0031] In some embodiments, in step S1, the molar ratio of tungstate to acid is 1:(3-6), for example, 1:3, 1:4, 1:5, 1:6 or other ratios within this range; the acid includes hydrochloric acid solution.

[0032] It is understandable that the molar ratio of tungstate to acid solution and the acid solution can be conventionally adjusted according to actual use needs, as long as the acidification reaction can be completed. In the present invention, the molar ratio of tungstate to acid solution is preferably 1: (3-6), and the acid solution preferably includes hydrochloric acid solution.

[0033] In some embodiments, in step S1, the temperature of the acidification reaction is 90-110°C, for example, it can be 90°C, 95°C, 100°C, 105°C, 110°C or other values within this range; the time is 2-4h, for example, it can be 2h, 2.5h, 3h, 3.5h, 4h or other values within this range; the extraction, separation and purification specifically includes: extraction, separation and purification using an organic solvent; wherein the organic solvent is selected from at least one of methyl tert-butyl ether and diethyl ether.

[0034] In the present invention, by controlling the temperature and time of the acidification reaction within a specific range, the acidification reaction can be completed, and phosphotungstic acid with higher purity can be further obtained.

[0035] It is understandable that the organic solvent can be routinely adjusted according to actual use needs, as long as it can efficiently extract phosphotungstic acid. In the present invention, the organic solvent is preferably selected from at least one of methyl tert-butyl ether and diethyl ether.

[0036] In some embodiments, in step S2, the molar ratio of phosphotungstic acid to the bismuth source is 1:(1-2), for example, 1:1, 1:1.2, 1:5, 1:1.8, 1:2 or other ratios within this range; and the second solvent includes water.

[0037] In the present invention, by controlling the molar ratio of phosphotungstic acid to the bismuth source within a specific range, the two are fully reacted to obtain bismuth phosphotungstic acid with higher purity.

[0038] It is understandable that the second solvent can be routinely adjusted according to actual use needs, as long as it can dissolve phosphotungstic acid. In the present invention, the second solvent preferably includes water.

[0039] In some embodiments, in step S2, the molar ratio of the bismuth source to the acid solution is 1:(6-9), for example, 1:6, 1:7, 1:8, 1:9 or other ratios within this range; the acid solution includes a hydrochloric acid solution.

[0040] It is understandable that the molar ratio of the bismuth source to the acid solution and the acid solution can be conventionally adjusted according to actual use needs, as long as a bismuth salt solution can be obtained. In the present invention, the molar ratio of the bismuth source to the acid solution is preferably 1: (6-9), and the acid solution preferably includes a hydrochloric acid solution.

[0041] In some embodiments, in step S2, the reaction temperature is 30-50°C, for example, it can be 30°C, 35°C, 40°C, 45°C, 50°C or other values within this range; the time is 1-3h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h or other values within this range; the separation and purification specifically includes: separation and purification using reduced pressure concentration; wherein the temperature of reduced pressure concentration is 90°C-110°C, for example, it can be 90°C, 95°C, 100°C, 105°C, 110°C or other values within this range.

[0042] In the present invention, by controlling the temperature and time of the reaction within a specific range, bismuth phosphotungstate with higher purity can be obtained.

[0043] It is understandable that the temperature of the reduced pressure concentration can be conventionally adjusted according to actual use needs, as long as bismuth phosphotungstate can be separated and purified. In the present invention, the temperature of the reduced pressure concentration is preferably 90°C-110°C.

[0044] In a second aspect, the present invention provides bismuth phosphotungstate, which is prepared by any of the above preparation methods.

[0045] The bismuth phosphotungstate provided by the present invention has good photocatalytic performance and good degradation efficiency for organic waste.

[0046] In a third aspect, the present invention provides the use of the above-mentioned bismuth phosphotungstate in the photocatalytic degradation of organic dyes.

[0047] In some embodiments, the organic dye includes at least one of methyl orange, methylene blue, and rhodamine B.

[0048] It is understandable that the organic dye can be routinely adjusted according to actual use needs, as long as it can be efficiently degraded by bismuth phosphotungstate. In the present invention, the organic dye preferably includes at least one of methyl orange, methylene blue, and rhodamine B.

[0049] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0050] See also Figure 1 , which is a flow chart of the preparation method of bismuth phosphotungstate of the present invention. Specifically, the preparation method of bismuth phosphotungstate includes the following steps: S1, mixing tungstate and hydrogen phosphate and dissolving them in a first solvent, then adding acid solution to carry out acidification reaction, and extracting, separating and purifying the obtained product to obtain phosphotungstic acid; S2, dissolving phosphotungstic acid in a second solvent to obtain a phosphotungstic acid solution; adding a bismuth source to the acid solution to dissolve it to obtain a bismuth salt solution; mixing the phosphotungstic acid solution and the bismuth salt solution and reacting them, and separating and purifying the obtained product to obtain bismuth phosphotungstic acid.

[0051] Example 1 A method for preparing bismuth phosphotungstate comprises the following steps: S1. Add 33.68g of sodium tungstate dihydrate and 11.00g of disodium hydrogen phosphate dodecahydrate to a three-necked flask, then add 46.32g of water, and heat to 100°C and reflux with stirring to dissolve. Use a constant pressure dropping funnel to add 26.94mL of concentrated hydrochloric acid dropwise within 30min. After the addition is complete, reflux and react for 3h. After the reaction is completed, add 100mL of ether and shake vigorously until the solution is divided into three layers. Separate the bottom layer and concentrate under reduced pressure at 30°C to obtain 22.79g of phosphotungstic acid solid. S2. Add 3.73 g of bismuth trioxide to a round-bottom flask, then add 2 mL of concentrated hydrochloric acid thereto, stir and dissolve at room temperature, weigh 11.5 g of phosphotungstic acid solid, stir and dissolve with 10 mL of deionized water to obtain a phosphotungstic acid solution; pour the phosphotungstic acid solution into the round-bottom flask at once, place it at 40°C, and stir to react for 2 hours; after the reaction is completed, place the reaction solution at 110°C and concentrate under reduced pressure to obtain bismuth phosphotungstate.

[0052] Example 2 A method for preparing bismuth phosphotungstate comprises the following steps: S1. Add 33.68g of sodium tungstate dihydrate and 11.00g of disodium hydrogen phosphate dodecahydrate to a three-necked flask, then add 46.32g of water, and heat to 100°C and reflux with stirring to dissolve. Use a constant pressure dropping funnel to add 40.41mL of concentrated hydrochloric acid dropwise within 30min. After the addition is complete, reflux and react for 3h. After the reaction is completed, add 100mL of ether and shake vigorously until the solution is divided into three layers. Separate the bottom layer and concentrate under reduced pressure at 30°C to obtain 22.54g of phosphotungstic acid solid. S2. Add 3.73 g of bismuth trioxide to a round-bottom flask, then add 2 mL of concentrated hydrochloric acid thereto, stir and dissolve at room temperature, weigh 11.5 g of phosphotungstic acid solid, stir and dissolve with 10 mL of deionized water to obtain a phosphotungstic acid solution; pour the phosphotungstic acid solution into the round-bottom flask at once, place it at 40°C, and stir to react for 2 hours; after the reaction is completed, place the reaction solution at 110°C and concentrate under reduced pressure to obtain bismuth phosphotungstate.

[0053] Example 3 A method for preparing bismuth phosphotungstate comprises the following steps: S1. Add 33.68g of sodium tungstate dihydrate and 11.00g of disodium hydrogen phosphate dodecahydrate to a three-necked flask, then add 46.32g of water, and heat to 100°C and reflux with stirring to dissolve. Use a constant pressure dropping funnel to add 26.94mL of concentrated hydrochloric acid dropwise within 30min. After the addition is complete, reflux and react for 3h. After the reaction is completed, add 100mL of methyl tert-butyl ether and shake vigorously until the solution is divided into three layers. Separate the bottom layer of the solution and concentrate under reduced pressure at 30°C to obtain 22.06g of phosphotungstic acid solid. S2. Add 3.73 g of bismuth trioxide to a round-bottom flask, then add 2 mL of concentrated hydrochloric acid thereto, stir and dissolve at room temperature, weigh 11.5 g of phosphotungstic acid solid, stir and dissolve with 10 mL of deionized water to obtain a phosphotungstic acid solution; pour the phosphotungstic acid solution into the round-bottom flask at once, place it at 40°C, and stir to react for 2 hours; after the reaction is completed, place the reaction solution at 110°C and concentrate under reduced pressure to obtain bismuth phosphotungstate.

[0054] Example 4 A method for preparing bismuth phosphotungstate comprises the following steps: S1. Add 33.68g of sodium tungstate dihydrate and 11.00g of disodium hydrogen phosphate dodecahydrate to a three-necked flask, then add 46.32g of water, and heat to 100°C and reflux with stirring to dissolve. Use a constant pressure dropping funnel to add 26.94mL of concentrated hydrochloric acid dropwise within 30min. After the addition is complete, reflux and react for 3h. After the reaction is completed, add 100mL of methyl tert-butyl ether and shake vigorously until the solution is divided into three layers. Separate the bottom layer of the solution and concentrate under reduced pressure at 30°C to obtain 22.06g of phosphotungstic acid solid. S2. Add 3.73 g of bismuth trioxide to a round-bottom flask, then add 4 mL of concentrated hydrochloric acid thereto, stir and dissolve at room temperature, weigh 11.5 g of phosphotungstic acid solid, stir and dissolve with 10 mL of deionized water to obtain a phosphotungstic acid solution; pour the phosphotungstic acid solution into the round-bottom flask at once, place it at 40°C, and stir to react for 2 hours; after the reaction is completed, place the reaction solution at 110°C and concentrate under reduced pressure to obtain bismuth phosphotungstate.

[0055] Example 5 A method for preparing bismuth phosphotungstate comprises the following steps: S1. Add 33.68g of sodium tungstate dihydrate and 11.00g of disodium hydrogen phosphate dodecahydrate to a three-necked flask, then add 46.32g of water, and heat to 100°C and reflux with stirring to dissolve. Use a constant pressure dropping funnel to add 26.94mL of concentrated hydrochloric acid dropwise within 30min. After the addition is complete, reflux and react for 3h. After the reaction is completed, add 100mL of methyl tert-butyl ether and shake vigorously until the solution is divided into three layers. Separate the bottom layer of the solution and concentrate under reduced pressure at 30°C to obtain 22.06g of phosphotungstic acid solid. S2. Add 3.73 g of bismuth trioxide to a round-bottom flask, then add 4 mL of concentrated hydrochloric acid thereto, stir and dissolve at room temperature, weigh 11.5 g of phosphotungstic acid solid, stir and dissolve with 10 mL of deionized water to obtain a phosphotungstic acid solution; pour the phosphotungstic acid solution into the round-bottom flask at once, place it at 40°C, and stir to react for 2 hours; after the reaction is completed, place the reaction solution at 90°C and concentrate under reduced pressure to obtain bismuth phosphotungstate.

[0056] Example 6 A method for preparing bismuth phosphotungstate comprises the following steps: S1. Add 33.68g of sodium tungstate dihydrate and 11.00g of disodium hydrogen phosphate dodecahydrate to a three-necked flask, then add 46.32g of water, and heat to 100°C and reflux with stirring to dissolve. Use a constant pressure dropping funnel to add 26.94mL of concentrated hydrochloric acid dropwise within 30min. After the addition is complete, reflux and react for 3h. After the reaction is completed, add 100mL of ether and shake vigorously until the solution is divided into three layers. Separate the bottom layer and concentrate under reduced pressure at 30°C to obtain 22.79g of phosphotungstic acid solid. S2. Add 3.73 g of bismuth trioxide to a round-bottom flask, then add 2 mL of concentrated hydrochloric acid thereto, stir and dissolve at room temperature, weigh 23.0 g of phosphotungstic acid solid, stir and dissolve with 10 mL of deionized water to obtain a phosphotungstic acid solution; pour the phosphotungstic acid solution into the round-bottom flask at once, place it at 40°C, and stir to react for 2 hours; after the reaction is completed, place the reaction solution at 110°C and concentrate under reduced pressure to obtain bismuth phosphotungstate.

[0057] Comparative Document 1 This comparative example provides a phosphorus-doped bismuth tungstate photocatalyst, which is prepared by referring to the method in Example 1 of the specification of Chinese patent application document CN113231088A.

[0058] Specifically, 0.485g of bismuth nitrate and 0.12g of phosphotungstic acid were placed in a beaker, 60ml of deionized water was added, and the mixture was stirred and ultrasonicated. The mixture was then poured into a hydrothermal reactor, which was placed in a tube furnace and heated to 150°C for 6 hours. The reaction solution was filtered, washed, and dried to obtain the target product, phosphorus-doped bismuth tungstate.

[0059] Performance Testing The photocatalytic properties of the bismuth phosphotungstate prepared in Examples 1-6 and the phosphorus-doped bismuth tungstate photocatalyst prepared in Comparative Example 1 were tested.

[0060] Specifically, the above-mentioned bismuth phosphotungstate and phosphorus-doped bismuth tungstate photocatalysts were calcined and activated at 200 ° C. 0.1 g of the activated bismuth phosphotungstate and phosphorus-doped bismuth tungstate photocatalysts were weighed and placed in a 250 mL beaker. 50 mL of 4.0 mg / L methyl orange solution was added, and the mixture was stirred in the dark for 10 min to mix evenly. Then, a photocatalytic reaction was carried out under light. After 2 h of reaction, 1 mL of the upper reaction liquid was pipetted with a pipette, centrifuged and filtered, and the filtrate was fixed to 25 mL. The substrate concentration was tested with an ultraviolet spectrophotometer to obtain the degradation rate. The results are shown in Table 1 below.

[0061] Table 1 Photocatalytic performance results of bismuth phosphotungstate

[0062] It can be seen from Table 1 that compared with the phosphorus-doped bismuth tungstate photocatalyst prepared in Comparative Example 1, the bismuth phosphotungstate prepared in Examples 1-6 of the present invention has better photocatalytic degradation effect.

[0063] Application test case In this application example, the degradation ability of the bismuth phosphotungstate prepared in Example 1 and the phosphorus-doped bismuth tungstate photocatalyst prepared in Comparative Example 1 on methyl orange wastewater was studied.

[0064] Specifically, 1 L of wastewater containing methyl orange organic dye (concentration of 2.0 mg / L) was added to the reaction flask, and 1 g of calcined activated bismuth phosphotungstate material and phosphorus-doped bismuth tungstate photocatalyst were added to the wastewater. The flask was first placed in a dark environment and stirred for 1 hour to redisperse the catalyst. Samples were taken, and the light was turned on for 2 hours. The two samples were sampled, centrifuged and filtered, and the absorbance of the corresponding wavelength was tested with an ultraviolet spectrophotometer. The degradation rate of methyl orange in the solution was calculated. The results are shown in Table 2.

[0065] Table 2 Degradation rate of bismuth phosphotungstate on methyl orange wastewater

[0066] As can be seen from the data in Table 2, compared with the phosphorus-doped bismuth tungstate photocatalyst prepared in Comparative Example 1, the bismuth phosphotungstate prepared in Example 1 of the present invention has a better degradation effect on methyl orange wastewater. Therefore, the bismuth phosphotungstate prepared in the present invention has good application prospects in the degradation of organic waste.

[0067] In summary, the bismuth phosphotungstate material prepared in the present invention has a special electronic structure. Therefore, it has good redox ability. Under light conditions, it absorbs light as energy and can convert organic waste into carbon dioxide and water, thereby achieving green and efficient degradation of organic waste.

[0068] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For any details not described in individual embodiments, reference may be made to the description in other embodiments.

[0069] The above-described embodiments merely illustrate the implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing bismuth phosphotungstate, characterized in that: The steps include: S1. Mixing tungstate and hydrogen phosphate and dissolving the mixture in a first solvent, then adding acid to carry out an acidification reaction, and extracting, separating, and purifying the obtained product to obtain phosphotungstic acid; S2, dissolving the phosphotungstic acid in a second solvent to obtain a phosphotungstic acid solution; adding a bismuth source into an acid solution and dissolving the bismuth source to obtain a bismuth salt solution; The phosphotungstic acid solution and the bismuth salt solution are mixed and reacted, and the obtained product is separated and purified to obtain bismuth phosphotungstate; Wherein, in step S2, the bismuth source includes bismuth trioxide.

2. The method for preparing bismuth phosphotungstate according to claim 1, wherein In step S1, the molar ratio of the tungstate to the hydrogen phosphate is 1:(0.2-0.4), the tungstate includes sodium tungstate dihydrate, and the hydrogen phosphate includes disodium hydrogen phosphate dodecahydrate.

3. The method for preparing bismuth phosphotungstate according to claim 1, wherein In step S1, the mass ratio of the tungstate to the first solvent is 1:(1.4-1.6), and the first solvent includes water.

4. The method for preparing bismuth phosphotungstate according to claim 1, wherein In step S1, the molar ratio of the tungstate to the acid solution is 1:(3-6), and the acid solution includes a hydrochloric acid solution.

5. The method for preparing bismuth phosphotungstate according to claim 1, wherein In step S1, the temperature of the acidification reaction is 90-110° C. and the time is 2-4 hours; the extraction, separation and purification specifically includes: extraction, separation and purification using an organic solvent; Wherein, the organic solvent is selected from at least one of methyl tert-butyl ether and diethyl ether.

6. The method for preparing bismuth phosphotungstate according to claim 1, wherein In step S2, the molar ratio of the phosphotungstic acid to the bismuth source is 1:(1-2), and the second solvent includes water.

7. The method for preparing bismuth phosphotungstate according to claim 1, wherein In step S2, the molar ratio of the bismuth source to the acid solution is 1:(6-9), and the acid solution includes a hydrochloric acid solution.

8. The method for preparing bismuth phosphotungstate according to claim 1, wherein In step S2, the reaction temperature is 30-50° C. and the reaction time is 1-3 hours; the separation and purification specifically includes: separation and purification by vacuum concentration; Wherein, the temperature of the reduced pressure concentration is 90°C-110°C.

9. A bismuth phosphotungstate, characterized in that The method is prepared according to any one of claims 1 to 8.

10. Use of the bismuth phosphotungstate according to claim 9 in photocatalytic degradation of organic dyes.

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