Composite photocatalyst and application thereof in wastewater treatment
By developing a composite photocatalyst, including activated carbon, bismuth oxybromide and silver oxide, the problem of removing multiple pollutants in industrial wastewater has been solved, continuous wastewater treatment under light and no light conditions has been achieved, and water reuse in the chemical industry has been achieved. Standard purification effect.
Patent Information
- Application Number
- CN202411596152.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-01-21
AI Technical Summary
The wastewater generated during industrial production contains a variety of pollutants, and the prior art is difficult to effectively remove these pollutants, resulting in environmental pollution and human health risks.
Develop a composite photocatalyst, including activated carbon, bromone oxygen, and silver oxide. Through specific preparation methods, bromine oxygen is evenly distributed on activated carbon, and silver oxide is evenly distributed on bromide cricket Material.
This composite photocatalyst not only has significant photocatalytic effect under light conditions, but can also continuously treat wastewater under no light conditions, effectively remove a variety of pollutants, reduce the COD value in industrial wastewater, and enable wastewater purification to reach the level of recycle water in the chemical industry. standard.
Smart Images
Figure CN119327489A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of photocatalysts, and in particular to a composite photocatalyst and application thereof in wastewater treatment. Background Art
[0002] A large amount of wastewater is generated during the industrial production process. The wastewater contains pollutants such as raw materials, intermediate products, and by-products. If not properly handled, it will cause serious pollution to the environment and affect human health, causing symptoms such as digestive tract, respiratory tract, and skin diseases, and even cancer in severe cases.
[0003] With the continuous development of my country's economy and science and technology, all sectors of society are paying more and more attention to the ecological environment. Therefore, it is of positive significance to purify industrial wastewater, purify wastewater, reduce pollution, and even recycle and reuse wastewater to make full use of water resources.
[0004] At present, photocatalytic technology as a green wastewater treatment method has attracted widespread attention in the industry. The development of a composite photocatalyst is of great significance for wastewater treatment. Summary of the invention
[0005] Based on the technical problems existing in the background technology, the present invention proposes a composite photocatalyst and its application in wastewater treatment.
[0006] The invention provides a composite photocatalyst comprising activated carbon, bismuth oxybromide and silver oxide.
[0007] The bismuth oxybromide is distributed on the activated carbon, and the silver oxide is distributed on the bismuth oxybromide;
[0008] The bismuth oxybromide is in the form of flakes, and has a particle size of 200-500 nm.
[0009] The silver oxide is in granular form with a particle size of 5-20 nm.
[0010] Preferably, the silver oxide may also be distributed on activated carbon.
[0011] The present invention also provides a method for preparing a composite photocatalyst, comprising the following steps:
[0012] S1. Activated carbon pretreatment: placing activated carbon in a pretreatment solution for ultrasonic treatment, and drying to obtain pretreated activated carbon;
[0013] S2, soaking the pretreated activated carbon in a bismuth salt solution, water, a bromide solution, and water in sequence, cyclically soaking, drying, to obtain a mixture A, mixing the mixture A with the mixed solution A for a solvothermal reaction, washing, and drying to obtain activated carbon loaded with bismuth oxybromide;
[0014] S3. Soaking the activated carbon loaded with bismuth oxybromide in silver salt solution, water, NaOH solution, and water in turn, cyclically soaking, and drying to obtain activated carbon loaded with bismuth oxybromide-silver oxide, i.e., a composite photocatalyst.
[0015] Preferably, in S1, the pretreatment solution is independently selected from one or more of ethanol, acetone, water, hydrochloric acid and sodium hydroxide.
[0016] Preferably, in S1, the ultrasonic treatment time is 5-30 min.
[0017] Preferably, the volume ratio of the pretreated activated carbon, bismuth salt solution, water, bromide solution, and water is (0.01-1):1:1:1:1:1.
[0018] Preferably, in said S2, the bismuth salt solution comprises a bismuth salt and a solvent.
[0019] More preferably, the bismuth salt is selected from one or more of bismuth nitrate, bismuth oxynitrate, bismuth citrate, bismuth chloride and bismuth acetate.
[0020] More preferably, the solvent is selected from one or more of DMF and ethylene glycol.
[0021] Preferably, in the S2, the concentration of the bismuth salt solution is 0.01-0.1 mol / L.
[0022] Preferably, in said S2, the bromide solution comprises bromide and a solvent.
[0023] Preferably, in said S2, the concentration of the bromide solution is 0.5-2 mol / L.
[0024] More preferably, the bromide is selected from one or more of potassium bromide and sodium bromide.
[0025] More preferably, the solvent is selected from one or more of water and DMF.
[0026] Preferably, in said S2, the mixed solution A comprises bismuth salt, bromide and ethylene glycol.
[0027] More preferably, the mass ratio of the bismuth salt, bromide and ethylene glycol is (1-2):(0.1-0.6):15.
[0028] Preferably, in said S3, the silver salt solution is a silver salt aqueous solution.
[0029] Preferably, in said S3, the concentration of the silver salt solution is 0.01-0.2 mol / L.
[0030] More preferably, the silver salt is selected from one or more of silver nitrate and silver sulfate.
[0031] Preferably, in S3, the NaOH solution is a NaOH aqueous solution.
[0032] Preferably, in said S3, the concentration of the NaOH solution is 0.1-0.5 mmol / L.
[0033] An application of the composite photocatalyst or the composite photocatalyst prepared by the preparation method in wastewater treatment.
[0034] The beneficial effects of the present invention are:
[0035] A composite photocatalyst proposed by the present invention includes activated carbon, bismuth oxybromide, and silver oxide, wherein the bismuth oxybromide is evenly distributed on the activated carbon, and the silver oxide is evenly distributed on the bismuth oxybromide; the energy band gap of bismuth oxybromide is 2.6-2.9eV, and the energy band gap of silver oxide is ~1.2eV. The combination of bismuth oxybromide and silver oxide effectively broadens the light response range and inhibits the recombination of electron-hole pairs. Pre-treating the activated carbon can, on the one hand, remove impurities on the surface of the activated carbon and improve the adsorption effect of the material, and on the other hand, it is conducive to the uniform loading of bismuth oxybromide and improves the photocatalytic performance of the material. The synergistic effect of activated carbon, bismuth oxybromide, and silver oxide makes the composite photocatalyst not only have excellent photocatalytic effect, but also improve its adsorption effect. In actual application, wastewater can still be continuously treated regardless of whether it is illuminated or not. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Figure 1 This is a SEM image of the composite photocatalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0037] The technical solution of the present invention is described in detail through specific embodiments.
[0038] Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples can be obtained from commercial sources.
[0039] Example 1
[0040] A method for preparing a composite photocatalyst comprises the following steps:
[0041] S1. Activated carbon pretreatment: The activated carbon was placed in a 30 wt% ethanol solution for ultrasonic treatment for 5 min, then placed in a 1 wt% NaOH solution for ultrasonic treatment for 10 min, and dried to obtain pretreated activated carbon;
[0042] S2, immersing the pretreated activated carbon in 0.05 mol / L bismuth nitrate solution, water, 1.1 mol / L potassium bromide solution, and water in sequence, circulating for 5 times, drying, and obtaining a mixture A, immersing the mixture A in the mixed solution A for solvent thermal reaction, washing, and drying to obtain activated carbon loaded with bismuth oxybromide; wherein the mass ratio of bismuth nitrate, potassium bromide, and ethylene glycol in the mixed solution A is 1:0.3:15;
[0043] S3. The activated carbon loaded with bismuth oxybromide is immersed in 0.05 mol / L silver nitrate solution, water, 0.2 mmol / L NaOH solution, and water in turn, and the cycle is repeated 5 times. The activated carbon loaded with bismuth oxybromide and silver oxide is obtained, i.e., a composite photocatalyst.
[0044] Example 2
[0045] A method for preparing a composite photocatalyst comprises the following steps:
[0046] S1. Activated carbon pretreatment: The activated carbon was placed in a mixed solution containing acetone and ethanol in a mass ratio of 1:1 and ultrasonically treated for 5 minutes, then placed in a 1wt% NaOH solution and ultrasonically treated for 5 minutes, and dried to obtain pretreated activated carbon;
[0047] S2, immersing the pretreated activated carbon in 0.04 mol / L bismuth nitrate solution, water, 0.08 mol / L potassium bromide solution, and water in sequence, circulating 5 times, drying, and obtaining a mixture A, immersing the mixture A in the mixed solution A for solvothermal reaction, washing, and drying to obtain activated carbon loaded with bismuth oxybromide; wherein the mass ratio of bismuth nitrate, sodium bromide, and ethylene glycol in the mixed solution A is 1.5:0.25:15;
[0048] S3. The activated carbon loaded with bismuth oxybromide is immersed in 0.04 mol / L silver nitrate solution, water, 0.1 mmol / L NaOH solution, and water in turn, and the cycle is repeated 5 times. The activated carbon loaded with bismuth oxybromide and silver oxide is obtained, i.e., a composite photocatalyst.
[0049] Example 3
[0050] A method for preparing a composite photocatalyst comprises the following steps:
[0051] S1. Activated carbon pretreatment: The activated carbon was ultrasonically treated in a 2 wt% hydrochloric acid solution for 10 min, washed until neutral and free of chloride ions, then ultrasonically treated in a 1.5 wt% NaOH solution for 10 min, and dried to obtain pretreated activated carbon;
[0052] S2, immersing the pretreated activated carbon in 0.06 mol / L bismuth nitrate solution, water, 1 mol / L potassium bromide solution, and water in turn, cycling for 5 times, drying to obtain a mixture A, immersing the mixture A in the mixed solution A for solvent thermal reaction, washing, and drying to obtain activated carbon loaded with bismuth oxybromide; wherein the mass ratio of bismuth nitrate, potassium bromide, and ethylene glycol in the mixed solution A is 1:0.3:15;
[0053] S3. The activated carbon loaded with bismuth oxybromide is immersed in 0.06 mol / L silver nitrate solution, water, 0.2 mmol / L NaOH solution, and water in turn, and the cycle is repeated 5 times. The activated carbon loaded with bismuth oxybromide and silver oxide is obtained, i.e., a composite photocatalyst.
[0054] Comparative Example 1
[0055] Activated carbon only.
[0056] Comparative Example 2
[0057] The only difference between Comparative Example 2 and Example 1 is that the S3 operation is not performed, that is, the composite photocatalyst is activated carbon loaded with bismuth oxybromide.
[0058] Comparative Example 3
[0059] The only difference between Comparative Example 3 and Example 1 is that no activated carbon is added, that is, the composite photocatalyst is bismuth oxybromide-silver oxide.
[0060] Application Example 1
[0061] The photocatalyst prepared above was used to degrade AO7 (Acid Orange 7) in wastewater. The specific steps are as follows: 5cm*5cm*5cm photocatalyst was placed in an aqueous solution containing 1L 20mg / LA AO7, stirred, and reacted for 1h in the dark, then turned on a 300w xenon lamp for photocatalytic reaction for 1.5h, and the absorbance of the sample was tested to calculate the removal efficiency. The test results are shown in Table 1.
[0062] Table 1
[0063] Group Removal efficiency under dark conditions Removal efficiency under light conditions Example 1 25％ 100％ Example 2 23％ 98％ Example 3 25％ 99％ Comparative Example 1 9％ 22％ Comparative Example 2 15％ 40％ Comparative Example 3 5％ 79％
[0064] Application Example 2
[0065] The photocatalyst prepared above was used to degrade TC (tetracycline) in wastewater. The specific steps are as follows: 5cm*5cm*5cm photocatalyst was placed in 1L of 10mg / LTC aqueous solution and stirred. The reaction was first carried out in the dark for 1h, and then a 300w xenon lamp was turned on for photocatalytic reaction. The absorbance of the sample was tested and the removal efficiency was calculated. The test results are shown in Table 2.
[0066] Table 2
[0067]
[0068]
[0069] Application Example 3
[0070] The composite photocatalyst prepared above was used for wastewater treatment. The specific steps are as follows: 5cm*5cm*5cm photocatalyst was placed in 1L of industrial wastewater, stirred, and reacted for 1h in the dark, then a 300w xenon lamp was turned on for photocatalytic reaction for 3h, and the COD value was tested by sampling, and the removal efficiency was calculated. The test results are shown in Table 3.
[0071] Table 3
[0072]
[0073] It can be seen from the data in Table 1-2 that the composite photocatalyst prepared by the present invention has a certain adsorption capacity for AO7 under dark conditions, mainly because AO7 is a dye and its color is easier to remove. However, for the pollutant TC, the adsorption effect is not obvious, and the degradation of TC in wastewater mainly relies on photocatalytic treatment. Therefore, different pollutants are treated in different ways, and the composite photocatalyst prepared by the present invention has both adsorption effect and photocatalytic effect, and can still continuously treat wastewater in the absence of light.
[0074] It can be seen from the data in Table 3 that the composite photocatalyst prepared by the present invention can effectively reduce the COD value in industrial wastewater, so that the wastewater purification can meet the reuse water standard of the chemical industry.
[0075] like Figure 1 As shown, Figure 1 This is the SEM image of the composite photocatalyst prepared in Example 1 of the present invention. It can be seen that granular silver oxide is evenly distributed on the flaky bismuth oxybromide material supported on the activated carbon. The particle size of the flaky bismuth oxybromide is 200-500nm, and the particle size of the granular silver oxide is 5-20nm.
[0076] In summary, the composite photocatalyst provided by the present invention can remove a variety of pollutants and effectively reduce the COD value in industrial wastewater, so that the wastewater purification meets the reuse water standard of the chemical industry.
[0077] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for preparing a composite photocatalyst, characterized in that: The following steps are involved: S1. Activated carbon pretreatment: placing activated carbon in a pretreatment solution for ultrasonic treatment, and drying to obtain pretreated activated carbon; S2, soaking the pretreated activated carbon in a bismuth salt solution, water, a bromide solution, and water in sequence, cyclically soaking, drying, to obtain a mixture A, mixing the mixture A with the mixed solution A for a solvothermal reaction, washing, and drying to obtain activated carbon loaded with bismuth oxybromide; S3. Soaking the activated carbon loaded with bismuth oxybromide in silver salt solution, water, NaOH solution, and water in turn, cyclically soaking, and drying to obtain activated carbon loaded with bismuth oxybromide-silver oxide, i.e., a composite photocatalyst.
2. The preparation method according to claim 1, characterized in that: In the above S1, the pretreatment solution is independently selected from one or more of ethanol, acetone, water, hydrochloric acid, and sodium hydroxide.
3. The preparation method according to claim 1, characterized in that: In the S2, the bismuth salt solution includes a bismuth salt and a solvent; the bismuth salt is selected from one or more of bismuth nitrate, bismuth oxynitrate, bismuth citrate, bismuth chloride, and bismuth acetate; and the solvent is selected from one or more of DMF and ethylene glycol.
4. The preparation method according to claim 1, characterized in that: In the S2, the bromide solution comprises bromide and a solvent; the bromide is selected from one or more of potassium bromide and sodium bromide; the solvent is selected from one or more of water and DMF.
5. The preparation method according to claim 1, characterized in that: In the S2, the concentration of the bismuth salt solution is 0.01-0.1 mol / L; the concentration of the bromide solution is 0.5-2 mol / L.
6. The preparation method according to claim 1, characterized in that: In the S2, the mixed solution A includes bismuth salt, bromide, and ethylene glycol.
7. The preparation method according to claim 1, characterized in that: In the S3, the concentration of the silver salt solution is 0.01-0.2 mol / L; the concentration of the NaOH solution is 0.1-0.5 mmol / L.
8. A composite photocatalyst obtained by the preparation method according to any one of claims 1 to 7, characterized in that: The invention comprises activated carbon, bismuth oxybromide and silver oxide, wherein the bismuth oxybromide is distributed on the activated carbon, and the silver oxide is distributed on the bismuth oxybromide.
9. Use of the composite photocatalyst according to claim 8 or the composite photocatalyst prepared by the preparation method according to any one of claims 1 to 7 in wastewater treatment.