A persulfate catalyst, its preparation method and application

Abstract

The application discloses a persulfate catalyst and a preparation method and application thereof. The persulfate catalyst is a graphite-iron / copper / manganese sulfide composite material, and is prepared by taking an alkaline manganese dry battery as raw material, disassembling, dissolving and hydrothermal reaction. The graphite-iron / copper / manganese sulfide composite material prepared by the application is used as the persulfate catalyst, and is used for treating bisphenol A-containing wastewater. The degradation rate of the bisphenol A reaches 100% within 10 minutes, the catalytic degradation effect on the bisphenol A is remarkable, and after being used for 5 times, there is no obvious activity attenuation, the pH range of the wastewater treated by the application is wide, and the degradation effect is good within the range of 3-12, which is helpful for further application of the persulfate advanced oxidation technology in the field of environmental water treatment. The application uses cheap and easily obtained raw materials as catalyst precursors, and can effectively recycle the alkaline manganese dry battery and obtain the efficient persulfate catalyst, which achieves two goals at one stroke.

Description

Technical Field

[0001] This invention relates to the fields of solid waste recycling, material synthesis, and water treatment technology, specifically to a persulfate catalyst, its preparation method, and its application, and more specifically to a method for preparing a persulfate catalyst using an alkaline manganese dry cell and its application in treating organic wastewater. Background Technology

[0002] Organic wastewater, due to its large discharge volume and difficulty in degradation, is a significant issue in water pollution control. Phenolic wastewater, a major source of organic wastewater from the petrochemical industry, is listed as a key hazardous wastewater to be addressed in my country's water pollution control efforts due to its high toxicity and polluting properties. my country's "Integrated Wastewater Discharge Standard" (GB8978-1996) clearly stipulates that phenolic substances are classified as Class II pollutants, and the discharge standards for Class I and II wastewater must not exceed 0.5 mg / L. –1 The level 3 standard shall not exceed 2.0 mg / L. –1 Therefore, reducing the concentration of phenols in the aquatic environment is a very urgent task. In recent years, advanced oxidation technologies based on persulfate have attracted widespread attention from researchers because they can generate highly oxidizing active species in situ for the efficient removal of organic pollutants from water.

[0003] Currently, the main methods for treating phenol-containing petrochemical wastewater include adsorption, evaporation and concentration, and activated sludge processes, but none of these can completely degrade bisphenol A (BPA). Persulfate advanced oxidation technology can completely degrade pollutants, but the traditional synthesis process of persulfate catalysts is complex and costly. Therefore, the preparation of inexpensive and widely available persulfate catalysts has attracted widespread attention.

[0004] Alkaline manganese dry cell batteries are an indispensable and convenient power source in people's daily lives, widely used in various small electrical appliances. However, the recycling of these batteries after they fail has always been a major challenge for the industry, as improper handling can easily lead to heavy metal pollution. Existing sorting and processing methods require strict disassembly and classification of various components, which are complex and costly. Therefore, developing simple, low-cost recycling methods with good application value remains a research focus of widespread interest.

[0005] To address the above problems, this invention is proposed. Summary of the Invention

[0006] This invention provides a method for preparing a highly efficient composite catalyst for the degradation of bisphenol A by persulfate, aiming to solve the catalyst source problem in existing advanced persulfate oxidation technologies. The non-metallic catalyst preparation method provided by this invention is simple, uses readily available and low-cost raw materials, and exhibits high catalytic degradation efficiency for bisphenol A. The technical solution adopted by this invention is as follows:

[0007] The first aspect of the present invention provides a persulfate catalyst, wherein the persulfate catalyst is a graphite-iron / copper / manganese sulfide composite material.

[0008] The second aspect of the present invention provides a method for preparing the persulfate catalyst described in the first aspect of the present invention, using an alkaline manganese dry cell as raw material, and preparing the persulfate catalyst after disassembly, dissolution and hydrothermal reaction.

[0009] Preferably, the alkaline manganese dry cell is an alkaline manganese dry cell that has been discharged and used.

[0010] Preferably, the preparation method includes the following steps:

[0011] (1) Discharge the alkaline manganese dry cell and disassemble it, remove the plastic part of the alkaline manganese dry cell, wash it with hot water and filter it to obtain a solid mixture; the solid mixture is a mixture containing graphite, manganese dioxide, copper, iron and other components; the purpose of this step is to remove alkaline soluble substances.

[0012] (2) Add acid to the solid mixture obtained in step (1), heat the mixture to dissolve the metal components, and obtain the first mixture;

[0013] (3) The first mixture obtained in step (2) is directly transferred to a hydrothermal reactor, a sulfur source is added, and a hydrothermal reaction is carried out to obtain a second mixture. The purpose of this step is to carry out a sulfidation reaction in a hydrothermal reactor to convert the metal components into corresponding sulfides and load them onto graphite.

[0014] (4) The second mixture obtained in step (3) is filtered, washed and dried to obtain the persulfate catalyst.

[0015] Preferably, in step (1), the temperature of the hot water washing is 50-90°C.

[0016] Preferably, in step (2), the acid is selected from 2-6M nitric acid, 2-9M sulfuric acid, or 1-10M hydrochloric acid;

[0017] In step (2), the conditions for heating the reaction are: reaction temperature of 60-95℃ and reaction time of 5-10h.

[0018] Preferably, in step (3), the sulfur source is selected from thiourea or thioacetamide;

[0019] In step (3), the hydrothermal reaction conditions are: a reaction temperature of 150–210°C and a reaction time of 8–24 h. More preferably, in step (3), the reaction temperature is 180°C and the reaction time is 18 h.

[0020] Preferably, in step (4), the drying temperature is 50-90℃ and the drying time is 3-24h.

[0021] A third aspect of the present invention provides an application of the persulfate catalyst described in the first aspect of the present invention, using it as a catalyst for treating organic wastewater.

[0022] Preferably, the persulfate catalyst is used to treat organic wastewater to improve treatment efficiency and stability, wherein the pH value of the organic wastewater is 3 to 12.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The persulfate catalyst of this invention is low in cost, simple in preparation method, high in degradation efficiency, good in stability, and applicable to a wide pH range of wastewater. Specific beneficial effects are as follows:

[0025] 1. The graphite-iron / copper / manganese sulfide composite material prepared by this invention can be used as a persulfate catalyst for the treatment of bisphenol A-containing wastewater. With the addition of sodium persulfate, bisphenol A can be degraded into pollution-free CO2 and H2O. Within 10 minutes of treatment, the degradation rate of bisphenol A reaches 100%, demonstrating a significant catalytic degradation effect on bisphenol A. This contributes to the further application of persulfate advanced oxidation technology in the field of environmental water treatment.

[0026] 2. This invention utilizes inexpensive and readily available waste alkaline manganese dry batteries as raw materials for catalyst preparation, effectively recycling alkaline manganese dry batteries while obtaining a highly efficient persulfate catalyst, achieving two goals at once. Furthermore, the preparation method of the persulfate catalyst using alkaline manganese dry batteries as raw materials—through dismantling, dissolution, and hydrothermal reaction—is simple.

[0027] 3. The persulfate catalyst of the present invention can be recycled after being filtered, washed with water and dried. After being recycled 5 times, there is no obvious activity decay.

[0028] 4. The persulfate catalyst of this invention has a good degradation effect under both alkaline and acidic wastewater conditions, and the pH range of the treated wastewater is 3 to 12, which is a wide range.

[0029] 5. The persulfate catalyst of this invention has a significant catalytic effect at room temperature, without the need to raise the system temperature, thus saving energy. Attached Figure Description

[0030] Figure 1 Here is a SEM image of the composite material prepared in Example 1;

[0031] Figure 2 The graph shows the concentration changes of the bisphenol A solution at different time points during the degradation of bisphenol A by the catalyst prepared in Example 1.

[0032] Figure 3The results are the stability test results of the catalyst prepared in Example 1;

[0033] Figure 4 The effect of the catalyst prepared in Example 1 on the degradation of bisphenol A at different pH values ​​is shown. Detailed Implementation

[0034] The present invention will be further described below through embodiments, but is not limited to these embodiments. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in manuals, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified.

[0035] The specific steps of the method described in this invention are as follows:

[0036] Example 1

[0037] (1) Discharge the two AA batteries and then disassemble them, removing the plastic parts;

[0038] (2) Place the battery component obtained in step (1) in 500mL of water, heat it to 60 degrees and keep it for 2 hours;

[0039] (3) Filter the washed parts obtained in step (2) to obtain a mixture of various solids;

[0040] (4) Add 100 mL of 30% nitric acid to the mixture from step (3) and heat to 60 degrees Celsius for 5 hours.

[0041] (5) Transfer all the product obtained in step (4) to a hydrothermal reactor, add 30g of thiourea, heat to 180 degrees and keep for 18 hours.

[0042] (6) After natural cooling, filter, wash twice with water and ethanol respectively, and then dry to obtain the final composite catalyst.

[0043] (7) Prepare 100 mL of 200 mg / L bisphenol A aqueous solution, add 5 mg of the complex material prepared in step (6) as a catalyst, add 0.1 g of sodium persulfate as an oxidant, and react under stirring in a water bath at 25 °C. Take samples at intervals and perform quantitative analysis using liquid chromatography.

[0044] Comparative Example 1

[0045] Prepare 100 mL of 200 mg / L bisphenol A aqueous solution, add 0.1 g sodium persulfate as an oxidant, and react under stirring in a water bath at 25 °C. Take samples at regular intervals and perform quantitative analysis using liquid chromatography.

[0046] The data for Example 1 and Comparative Example 1 are shown below. Figure 2,from Figure 2 As can be seen from the example, the graphite-iron / copper / manganese sulfide composite material in Example 1 is used to treat bisphenol A-containing wastewater. With the addition of sodium persulfate, bisphenol A can be degraded into non-polluting CO2 and H2O. Within 10 minutes of treatment, the degradation rate of bisphenol A reaches 100%. However, when sodium persulfate is added alone, the concentration of bisphenol A does not decrease after 30 minutes.

[0047] The acid used in Example 2 was 30% hydrochloric acid.

[0048] (1) Discharge the two AA batteries and then disassemble them, removing the plastic parts;

[0049] (2) Place the battery component obtained in step (1) in 500mL of water, heat it to 60 degrees and keep it for 2 hours;

[0050] (3) Filter the washed parts obtained in step (2) to obtain a mixture of various solids.

[0051] (4) Add 100 mL of 30% hydrochloric acid to the mixture in step (3) and heat to 60 degrees Celsius for 5 hours;

[0052] (5) Transfer all the product obtained in step (4) to a hydrothermal reactor, add 30g of thiourea, heat to 180 degrees and keep for 18 hours.

[0053] (6) After natural cooling, filter, wash twice with water and ethanol respectively to obtain the final composite catalyst.

[0054] (7) Prepare 100 mL of 200 mg / L bisphenol A aqueous solution, add 5 mg of the complex material prepared in step (6) as a catalyst, add 0.1 g of sodium persulfate as an oxidant, and react under stirring in a water bath at 25 °C. Take samples at intervals and perform quantitative analysis using liquid chromatography.

[0055] The acid used in Example 3 was 30% dilute sulfuric acid.

[0056] (1) Discharge the two AA batteries and then disassemble them, removing the plastic parts;

[0057] (2) Place the battery component obtained in step (1) in 500mL of water, heat it to 60 degrees and keep it for 2 hours;

[0058] (3) Filter the washed parts obtained in step (2) to obtain a mixture of various solids.

[0059] (4) Add 100 mL of 30% dilute sulfuric acid to the mixture in step (3) and heat to 60 degrees Celsius for 5 hours;

[0060] (5) Transfer all the product obtained in step (4) to a hydrothermal reactor, add 30g of thiourea, heat to 180 degrees and keep for 18 hours.

[0061] (6) After natural cooling, filter, wash twice with water and ethanol respectively to obtain the final composite catalyst.

[0062] (7) Prepare 100 mL of 200 mg / L bisphenol A aqueous solution, add 5 mg of the complex material prepared in step (6) as a catalyst, add 0.1 g of sodium persulfate as an oxidant, and react under stirring in a water bath at 25 °C. Take samples at intervals and perform quantitative analysis using liquid chromatography.

[0063] A comparison of Examples 1, 2, and 3 shows that the persulfate catalyst obtained by using 30% dilute sulfuric acid or 30% hydrochloric acid in the acid dissolution step can achieve the deep degradation of bisphenol A.

[0064] Example 4: The sulfur source is thioacetamide

[0065] (1) Discharge the two AA batteries and then disassemble them, removing the plastic parts;

[0066] (2) Place the battery component obtained in step (1) in 500mL of water, heat it to 60 degrees and keep it for 2 hours;

[0067] (3) Filter the washed parts obtained in step (2) to obtain a mixture of various solids.

[0068] (4) Add 100 mL of 30% nitric acid to the mixture from step (3) and heat to 60 degrees Celsius for 5 hours.

[0069] (5) Transfer all the product obtained in step (4) to a hydrothermal reactor, add 30g of thioacetamide, heat to 160 degrees and keep for 16 hours.

[0070] (6) After natural cooling, filter, wash twice with water and ethanol respectively to obtain the final composite catalyst.

[0071] (7) Prepare 100 mL of 200 mg / L bisphenol A aqueous solution, add 5 mg of the complex material prepared in step (6) as a catalyst, add 0.1 g of sodium persulfate as an oxidant, and react under stirring in a water bath at 25 °C. Take samples at intervals and perform quantitative analysis using liquid chromatography.

[0072] A comparison of Examples 1 and 4 shows that a high-performance catalyst can be obtained using thiourea, which has a lower cost.

[0073] Example 5: Different hydrothermal reaction temperatures

[0074] (1) Discharge the two AA batteries and then disassemble them, removing the plastic parts;

[0075] (2) Place the battery component obtained in step (1) in 500mL of water, heat it to 60 degrees and keep it for 2 hours;

[0076] (3) Filter the washed parts obtained in step (2) to obtain a mixture of various solids.

[0077] (4) Add 100 mL of 30% hydrochloric acid to the mixture in step (3) and heat to 60 degrees Celsius for 5 hours;

[0078] (5) Transfer all the product obtained in step (4) to a hydrothermal reactor, add 30g of thioacetamide, heat to 160 degrees and keep for 16 hours.

[0079] (6) After natural cooling, filter, wash twice with water and ethanol respectively to obtain the final composite catalyst.

[0080] (7) Prepare 100 mL of 200 mg / L bisphenol A aqueous solution, add 5 mg of the complex material prepared in step (6) as a catalyst, add 0.1 g of sodium persulfate as an oxidant, and react under stirring in a water bath at 25 °C. Take samples at intervals and perform quantitative analysis using liquid chromatography.

[0081] A comparison of Examples 2 and 5 shows that temperature and time have a significant impact on catalyst activity in hydrothermal reactions, with catalysts obtained at 180 degrees Celsius and for 18 hours exhibiting better activity.

[0082] Example 6 Stability Test

[0083] In this embodiment, the catalyst prepared in Example 1 was used for stability testing, and the results are as follows: Figure 3 As shown, its activity did not decrease significantly after 5 cycles of testing.

[0084] Example 7: Test of Bisphenol A Degradation at Different pH Values

[0085] In Examples 1-6, without pH adjustment, the initial pH was ~5. In this example, the initial pH was adjusted using sulfuric acid and sodium hydroxide solutions, and the catalyst prepared in Example 1 was tested at pH 3, 7, 10, and 12. The results were then compared with those of Example 1. Figure 4 As shown, it was found that it has good catalytic activity in the pH range of 3 to 12 and can be completely degraded within 20 minutes.

[0086] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a persulfate catalyst, characterized in that, The persulfate catalyst is a graphite-iron / copper / manganese sulfide composite material; The preparation method is as follows: using alkaline manganese dry batteries as raw materials, the persulfate catalyst is prepared after disassembly, dissolution and hydrothermal reaction; The preparation method includes the following steps: (1) Discharge the alkaline manganese dry cell, disassemble it, remove the plastic part of the alkaline manganese dry cell, wash it with hot water and filter it to obtain a solid mixture. (2) Add acid to the solid mixture obtained in step (1), heat the mixture to dissolve the metal components, and obtain the first mixture; (3) Transfer the first mixture obtained in step (2) to a hydrothermal reactor, add a sulfur source, and carry out a hydrothermal reaction to obtain the second mixture; (4) The second mixture obtained in step (3) is filtered, washed and dried to obtain the persulfate catalyst.

2. The preparation method according to claim 1, characterized in that, The alkaline manganese dry cell is an alkaline manganese dry cell that has been discharged and used.

3. The preparation method according to claim 1, characterized in that, In step (1), the temperature of the hot water washing is 50~90℃.

4. The preparation method according to claim 1, characterized in that, In step (2), the acid is selected from 2-6M nitric acid, 2-9M sulfuric acid, or 1-10M hydrochloric acid; In step (2), the conditions for heating the reaction are: reaction temperature of 60~95℃ and reaction time of 5~10 h.

5. The preparation method according to claim 1, characterized in that, In step (3), the sulfur source is selected from thiourea or thioacetamide; In step (3), the hydrothermal reaction conditions are: reaction temperature of 150~210℃ and reaction time of 8~24 h.

6. The preparation method according to claim 1, characterized in that, In step (4), the drying temperature is 50~90℃ and the drying time is 3~24h.

7. The application of a persulfate catalyst prepared by the preparation method according to any one of claims 1-6, characterized in that, It is used as a catalyst to treat organic wastewater.

8. The application according to claim 7, characterized in that, The persulfate catalyst is used to treat organic wastewater to improve treatment efficiency and stability, wherein the pH value of the organic wastewater is 3-12.

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