Preparation and application of activated carbon for hydrogen peroxide electrocatalysis of industrial sewage

Abstract

The invention discloses a preparation method of hydrogen peroxide electrocatalytic activated carbon for industrial sewage. The preparation method comprises the following steps: heating and carbonizing food residue bean products, grafting polyaniline, and treating in a nitric acid solution. The prepared product is placed in an electrode and placed in a 0.1 mol / L KOH aqueous solution, oxygen is introduced, and H2O2 can be produced. The generated H2O2 can be used for sewage treatment. The catalytic active sites and the performance of the activated carbon are improved by utilizing physical and chemical methods and combining temperature, time and atmosphere processes. The activated carbon prepared by the invention can be used for electrocatalytic synthesis of H2O2, and the yield of H2O2 is improved. The sewage treatment cost can be reduced, and the sewage treatment efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of activated carbon industrial sewage treatment, and in particular to the preparation and application of activated carbon for hydrogen peroxide electrocatalysis of industrial sewage. Background Art

[0002] With the continuous increase in industrial projects in my country's cities, the amount of wastewater discharged from industrial areas has also increased exponentially. Furthermore, industrial wastewater contains complex components, many of which are difficult to degrade, and traditional wastewater treatment processes (biotechnology, physical methods, and conventional chemical oxidation) struggle to effectively degrade these organic substances and improve the biodegradability of the wastewater. Since 2002, my country's sewage treatment plants have primarily used sodium hypochlorite as an oxidant. However, sodium hypochlorite has limited ability to oxidize the difficult-to-degrade organic pollutants in industrial wastewater, resulting in its less than ideal performance in industrial wastewater treatment.

[0003] In recent years, hydrogen peroxide (H2O2), as the "cleanest" chemical, not only has the advantages of being safe and non-corrosive, simple equipment, no secondary pollution, and high oxidation selectivity, but also can treat a variety of harmful substances (sulfides, cyanides, phenols, dye wastewater, coking wastewater, etc.), showing good application prospects in sewage treatment applications. In addition, H2O2 can also be used in combination with other oxidation methods (ozone oxidation, ultraviolet irradiation, etc.) to effectively treat difficult-to-decompose organic pollutants in industrial wastewater. Current research shows that the amount of H2O2 required to treat 1000g of industrial wastewater (wastewater with a COD of 500mg / L) is only about 250mg. However, since the current industrial production of H2O2 uses the anthraquinone method, its production cost is high, and its flammable and explosive properties increase transportation and storage costs, resulting in its application in industrial wastewater treatment being greatly limited.

[0004] The electrocatalytic oxygen reduction reaction (ORR) is a hot topic in current H2O2 production research. It enables continuous H2O2 synthesis at room temperature and pressure, boasting advantages such as process simplicity, safety, environmental friendliness, low cost, and controllable mass production. However, most commercial activated carbons have low catalytic activity sites. Furthermore, many raw materials are industrial products, making them unsuitable for low-carbon production. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology. The present invention develops high-quality activated carbon with efficient electrocatalytic synthesis of H2O2, realizes simple, efficient, safe and environmentally friendly controllable continuous synthesis of H2O2, improves the treatment effect of sewage treatment plants on industrial wastewater and reduces the cost of industrial wastewater treatment.

[0006] The technical solution adopted in the present invention is:

[0007] 1. A method for preparing activated carbon by electrocatalysis of hydrogen peroxide from industrial wastewater, comprising the following steps:

[0008] 1) Adding leftover soy products to deionized water, heating at 180°C for 24-48 hours, filtering, and freeze-drying the residue for 24-48 hours. Grinding and heating at 700-800°C under a CO2 atmosphere for 2-5 hours, and then heating under a N2 atmosphere for 2-5 hours at a heating rate of 5°C / min to obtain product A;

[0009] 2) Aniline and the product A prepared in step 1) are dispersed in a hydrochloric acid solution and stirred for 30-60 minutes to obtain a mixture A; an initiator is dissolved in the hydrochloric acid solution and stirred for 30-60 minutes to obtain a mixture B, which is added dropwise to the mixture A and stirred for 1-2 hours. The mixture is reacted in an ice-water bath for 24-48 hours, filtered by centrifugation, and the residue is washed with ethanol and deionized water until the pH is neutral, and freeze-dried for 24-48 hours to obtain a product B;

[0010] 3) Dispersing the product B prepared in step 2) in a nitric acid solution for 30 to 60 minutes, allowing it to stand for 6 to 12 hours, and filtering the residue. Washing the residue with ethanol and deionized water until the pH is neutral, and freeze-drying it for 24 to 48 hours to obtain product C.

[0011] Furthermore, the leftover soy products in step 1) can be one or more of cooked soybeans, tofu, and soy milk; and the mass ratio of the leftover soy products to deionized water is 1:1-2.

[0012] Furthermore, in step 2), the concentration of the hydrochloric acid solution in the mixture A is 1 to 2 mol / L, and the mass ratio of aniline to product A to hydrochloric acid solution is 1:0.1 to 0.2:3 to 10; in step 2), the concentration of the hydrochloric acid solution in the mixture B is 1 to 2 mol / L, and the mass ratio of the initiator to the hydrochloric acid solution is 1:50 to 100; in step 2), the initiator is one or more of potassium persulfate and ammonium persulfate; and in step 2), the ratio of aniline to initiator is 20 to 50:1.

[0013] Furthermore, the concentration of the nitric acid solution in step 3) is 2-3 mol / L; the mass ratio of product B to the nitric acid solution is 1:50-100.

[0014] An application of activated carbon for the electrocatalysis of hydrogen peroxide in industrial wastewater is characterized in that the prepared product C is placed in an electrode and oxygen is introduced into a 0.1 mol / L KOH aqueous solution to produce H2O2.

[0015] The invention discloses an application of activated carbon for electrocatalysis of hydrogen peroxide in industrial sewage, characterized in that the generated H2O2 can be used for sewage treatment.

[0016] Beneficial effects

[0017] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0018] (1) Using physical and chemical methods, combined with temperature, time, and atmosphere processes, the activated carbon is optimized in terms of pore structure, surface functional groups, and heteroatom doping. After in-situ carbonization of leftover soy products, N and S self-doping can be achieved. CO2 can increase the grafting rate of subsequent chemical modification and improve the catalytic active sites and performance of activated carbon.

[0019] (2) The activated carbon prepared by the present invention can electrocatalytically synthesize H2O2, thereby increasing the H2O2 yield, reducing the cost of sewage treatment, and improving the efficiency of sewage treatment.

[0020] (3) The selection of raw materials focuses on turning waste into treasure, which is more economical and low-carbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a scanning electron microscope image of product C in Example 1.

[0022] Figure 2 This is the EDS diagram of product A in Example 1. DETAILED DESCRIPTION

[0023] The present invention is described in detail below by way of examples, which are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. It should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and such equivalent forms also fall within the scope defined by the claims appended hereto.

[0024] Example 1

[0025] 1) Add leftover cooked soybeans (refer to https: / / baijiahao.baidu.com / s?id=1785416285594945678&wfr=spider&for=pc, step 2, pressure cooker cooking) to deionized water, heat at 180°C for 48 hours, filter, freeze-dry the residue for 48 hours, grind, and heat at 800°C under a CO atmosphere for 3 hours, then under a N atmosphere for 3 hours at a heating rate of 5°C / min to obtain product A;

[0026] 2) Dispersing 10 g of aniline and 2 g of the product A prepared in step 1) in 100 g of a 1 mol / L hydrochloric acid solution and stirring for 60 min to obtain a mixture A; dissolving 0.5 g of potassium persulfate in 30 g of a 1 mol / L hydrochloric acid solution and stirring for 60 min to obtain a mixture B, which was dropwise added to the mixture A, stirred for 1 h, reacted in an ice-water bath for 24 h, centrifuged, and the residue washed with ethanol and deionized water until the pH was neutral, and freeze-dried for 24 h to obtain a product B;

[0027] 3) 2 g of the product B prepared in step 2) was dispersed in 100 g of a 2 mol / L nitric acid solution for 45 min, allowed to stand for 8 h, and filtered. The filter residue was washed with ethanol and deionized water until the pH was neutral, and freeze-dried for 48 h to obtain product C.

[0028] Example 2

[0029] 1) Add leftover tofu to deionized water, heat at 180°C for 24 hours, filter, freeze-dry the residue for 24 hours, grind, and heat at 750°C under a CO2 atmosphere for 2 hours, then under a N2 atmosphere for 2 hours at a heating rate of 5°C / min to obtain product A;

[0030] 2) Dispersing 10 g of aniline and 1.5 g of the product A prepared in step 1) in 50 g of a 2 mol / L hydrochloric acid solution and stirring for 30 minutes to obtain a mixture A; dissolving 0.5 g of ammonium persulfate in 40 g of a 2 mol / L hydrochloric acid solution and stirring for 30 minutes to obtain a mixture B; adding the mixture B dropwise to the mixture A and stirring for 1 hour. The mixture was reacted in an ice-water bath for 24 hours, centrifuged, and the residue was washed with ethanol and deionized water until the pH was neutral, and freeze-dried for 24 hours to obtain a product B;

[0031] 3) 2 g of the product B prepared in step 2) was dispersed in 150 g of a 3 mol / L nitric acid solution for 60 min, allowed to stand for 6 h, and filtered. The filter residue was washed with ethanol and deionized water until the pH was neutral, and freeze-dried for 48 h to obtain product C.

[0032] Example 3

[0033] 1) Add leftover soy milk to deionized water, heat at 180°C for 24 hours, filter, freeze-dry the residue for 24 hours, grind, and heat at 800°C under a CO2 atmosphere for 5 hours, then under a N2 atmosphere for 5 hours at a heating rate of 5°C / min to obtain product A;

[0034] 2) Dispersing 10 g of aniline and 1 g of the product A prepared in step 1) in 100 g of a 1 mol / L hydrochloric acid solution and stirring for 60 min to obtain a mixture A; dissolving 0.5 g of ammonium persulfate in 50 g of a 1 mol / L hydrochloric acid solution and stirring for 60 min to obtain a mixture B, which was added dropwise to the mixture A, stirred for 1 h, reacted in an ice-water bath for 24 h, centrifuged, and the residue was washed with ethanol and deionized water until the pH was neutral, and freeze-dried for 24 h to obtain a product B;

[0035] 3) Product B prepared in step 2) was dispersed in a nitric acid solution for 30 to 60 minutes, allowed to stand for 6 hours, and then filtered. The filter residue was washed with ethanol and deionized water until the pH was neutral, and freeze-dried for 48 hours to obtain product C.

[0036] Comparative Example

[0037] Compared with Example 1, Comparative Example 1 is the same as Example 1 except that CO2 is not passed in step 1).

[0038] Compared with Example 1, Comparative Example 2 does not include step 2) and step 3), and the rest is the same as Example 1.

[0039] Compared with Example 1, Comparative Example 3 does not have step 2), and the rest is the same as Example 1.

[0040] Example and comparative example test results table

[0041]

[0042] H2O2 yield test: O2 was electrocatalytically reduced to H2O2 in a 0.1 mol / L KOH solution. Using a three-electrode method in a flow cell setup, the H2O2 yield reached 316 mg L at a potential of 0.4 V. -1 h -1 .

[0043] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements, or modifications based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are all included in the scope of protection of the present invention.

Claims

1. A method for preparing activated carbon by electrocatalysis of hydrogen peroxide from industrial wastewater, characterized in that: The steps include: 1) Adding leftover soy products to deionized water, heating at 180°C for 24-48 hours, filtering, and freeze-drying the residue for 24-48 hours. Grinding and heating at 700-800°C under a CO2 atmosphere for 2-5 hours, and then heating under a N2 atmosphere for 2-5 hours at a heating rate of 5°C / min to obtain product A; 2) Aniline and the product A prepared in step 1) are dispersed in a hydrochloric acid solution and stirred for 30-60 minutes to obtain a mixture A; an initiator is dissolved in the hydrochloric acid solution and stirred for 30-60 minutes to obtain a mixture B, which is added dropwise to the mixture A and stirred for 1-2 hours. The mixture is reacted in an ice-water bath for 24-48 hours, filtered by centrifugation, and the residue is washed with ethanol and deionized water until the pH is neutral, and freeze-dried for 24-48 hours to obtain a product B; 3) Dispersing the product B prepared in step 2) in a nitric acid solution for 30 to 60 minutes, allowing it to stand for 6 to 12 hours, and filtering the residue. Washing the residue with ethanol and deionized water until the pH is neutral, and freeze-drying it for 24 to 48 hours to obtain product C.

2. The preparation of activated carbon for hydrogen peroxide electrocatalysis in industrial wastewater according to claim 1, characterized in that: Step 1) The leftover soy product can be one or more of leftover cooked soybeans, tofu, and soy milk; the mass ratio of the leftover soy product to deionized water is 1:1-2.

3. The preparation of activated carbon for hydrogen peroxide electrocatalysis in industrial wastewater according to claim 1, characterized in that: In step 2), the concentration of the hydrochloric acid solution in the mixture A is 1 to 2 mol / L, and the mass ratio of aniline to product A to the hydrochloric acid solution is 1:0.1 to 0.2:3 to 10; in step 2), the concentration of the hydrochloric acid solution in the mixture B is 1 to 2 mol / L, and the mass ratio of the initiator to the hydrochloric acid solution is 1:50 to 100; in step 2), the ratio of aniline to initiator is 20 to 50:1; and in step 2), the initiator is one or more of potassium persulfate and ammonium persulfate.

4. The preparation of activated carbon for hydrogen peroxide electrocatalysis in industrial wastewater according to claim 1, characterized in that: Furthermore, the concentration of the nitric acid solution in step 3) is 2-3 mol / L; the mass ratio of product B to the nitric acid solution is 1:50-100.

5. An application of the activated carbon prepared according to claims 1 to 4, characterized in that: The product C described in claim 1 is placed in an electrode and introduced into a 0.1 mol / L KOH aqueous solution to produce H2O. 2， The generated H2O2 can be used for sewage treatment.

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