A method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode

Abstract

The application provides a preparation method of a three-dimensional carbon-based metal oxide electrocatalytic electrode, and sewage is treated by using the prepared electrocatalytic electrode, wherein the electrocatalytic electrode is prepared by configuring a manganese nitrate, copper nitrate and polyvinylpyrrolidone reaction solution, drying the reaction solution to form a precursor, carbonizing the precursor in a tube furnace under an inert gas atmosphere, and finally performing annealing treatment on the precursor in a muffle furnace to obtain MnO2 / CuO-NCNF-NCNF. The electrocatalytic electrode can effectively remove COD and nitrogen-containing substances in sewage, the preparation method is simple, environment-friendly, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment material preparation and application, specifically to a method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode and its application in electrocatalytic wastewater treatment. Background Technology

[0002] In recent years, environmental pollution has attracted widespread attention, with water pollution becoming increasingly serious. The COD (Chemical Oxygen Demand) and total nitrogen content in wastewater can have a significant impact on the ecological health of aquatic areas.

[0003] Organic matter in wastewater can be decomposed by the biochemical action of microorganisms. However, this decomposition process consumes oxygen, leading to a reduction in dissolved oxygen in the water. This negatively impacts the growth of fish and other aquatic organisms and microorganisms, affecting the aquatic ecosystem. When oxygen levels are low, organic matter undergoes anaerobic decomposition, producing unpleasant odors such as hydrogen sulfide, ammonia, and thiols, further deteriorating water quality. Therefore, finding effective technologies for degrading organic wastewater has become a hot topic in environmental remediation.

[0004] With increasingly stringent wastewater discharge standards, industrial wastewater treatment technologies need to be upgraded to remove recalcitrant organic matter from the water. Current methods for treating industrial wastewater, particularly organic wastewater, typically include biological treatment, advanced oxidation processes, adsorption, and membrane separation.

[0005] Transition metal oxide electrode materials possess advantages such as high capacitance, good catalytic effect, and economy, and have great application prospects. Currently, there is much research on metal oxide electrode materials, but most of them suffer from problems such as high resistance, poor mass transfer, high energy consumption, and short electrode lifetime. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode. By selecting three-dimensional carbon materials as the matrix material, the three-dimensional carbon-based metal oxide electrode is prepared, which has a large specific surface area, a large number of active sites, and the synergistic effect of Cu and Mn elements to improve the catalytic performance of the material.

[0007] To achieve the above objectives, according to the present invention, a method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode is characterized by the following preparation steps:

[0008] (1) Prepare a pre-reaction mixture of manganese, copper and PVP in a certain proportion, stir evenly, and dry for a certain time to obtain the precursor; (2) In a tube furnace, under an inert gas atmosphere, heat and carbonize to obtain Mn / Cu-NCNF; (3) Finally, anneal in a muffle furnace to obtain MnO2 / CuO-NCNF.

[0009] A method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode, wherein in step (1), the optimal manganese source is manganese nitrate hexahydrate; the optimal copper source is copper nitrate trihydrate; and the optimal carbon source is polyvinylpyrrolidone.

[0010] A method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode, wherein in step (1), the ratio of manganese, copper, and PVP in the pre-reaction solution is (0.3-0.8:0.3-0.8:0.8-1.5), with an optimal ratio of (0.5:0.5:1). In step (1), the stirring time is 30-60 minutes, with an optimal stirring time of 30 minutes, and the heating temperature is 60-100℃, with an optimal heating temperature of 80℃.

[0011] A method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode, wherein in step (2), the inert gas is nitrogen or argon, preferably nitrogen; the heating rate of the tube furnace is 5-15℃ / min, preferably 5℃ / min; the firing temperature is 600-1000℃, preferably 700℃; and the holding time is 2-6h, preferably 2h.

[0012] A method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode, wherein in step (3), the heating rate of the muffle furnace is 5-15℃ / min, with the optimum being 5℃ / min, the annealing temperature is 250-300℃, with the optimum being 250℃, and the annealing time is 3-5 hours, with the optimum being 3 hours.

[0013] Compared with the prior art, the present invention has the following advantages and technical effects:

[0014] 1) The three-dimensional carbon-based metal oxide electrocatalytic electrode prepared by this invention has a three-dimensional structure and is a novel three-dimensional electrode material with the characteristics of large specific surface area, many active sites, and synergistic effect of bimetallic elements.

[0015] 2) The three-dimensional carbon-based metal oxide electrocatalytic electrode prepared by this invention has a simple process, low cost, environmental friendliness, high yield, and is suitable for commercialization.

[0016] 3) In practical effect tests, the three-dimensional carbon-based metal oxide electrocatalytic electrode prepared by the present invention showed a significant improvement in degradation efficiency under the same conditions, with a degradation rate of over 94% within 30 minutes. Detailed Implementation

[0017] Example 1:

[0018] (1) Weigh 0.5g manganese nitrate hexahydrate, 0.5g copper nitrate trihydrate and 1g polyvinylpyrrolidone and dissolve them in deionized water. Stir for 30 minutes to mix evenly and dry in an oven at 80℃. Grind the dried product into powder.

[0019] (2) In a tube furnace, under a nitrogen atmosphere, the temperature is increased to 700℃ at 5℃ / min, held for 2 hours, and then the black powder is collected after cooling.

[0020] (3) The black powder was annealed in a muffle furnace at 250°C for 3 h at a heating rate of 5°C / min to obtain MnO2 / CuO-NCNF.

[0021] Example 2:

[0022] (1) Weigh 0.3g manganese nitrate hexahydrate, 0.3g copper nitrate trihydrate and 0.8g polyvinylpyrrolidone and dissolve them in deionized water. Stir for 30 minutes to mix evenly. Dry in an oven at 80℃. Grind the dried product into powder.

[0023] (2) In a tube furnace, under a nitrogen atmosphere, the temperature is increased to 700℃ at 5℃ / min, held for 2 hours, and then the black powder is collected after cooling.

[0024] (3) The black powder was annealed in a muffle furnace at 250°C for 3 h at a heating rate of 5°C / min to obtain MnO2 / CuO-NCNF.

[0025] Example 3:

[0026] (1) Weigh 0.8g manganese nitrate hexahydrate, 0.8g copper nitrate trihydrate and 1.5g polyvinylpyrrolidone and dissolve them in deionized water. Stir for 30 minutes to mix evenly and dry in an oven at 80℃. Grind the dried product into powder.

[0027] (2) In a tube furnace, under a nitrogen atmosphere, the temperature is increased to 700℃ at 5℃ / min, held for 2 hours, and then the black powder is collected after cooling.

[0028] (3) The black powder was annealed in a muffle furnace at 250°C for 3 h at a heating rate of 5°C / min to obtain MnO2 / CuO-NCNF.

[0029] Example 4:

[0030] (1) Weigh 0.5g manganese nitrate hexahydrate, 0.5g copper nitrate trihydrate and 1g polyvinylpyrrolidone and dissolve them in deionized water. Stir for 30 minutes to mix evenly and dry in an oven at 80℃. Grind the dried product into powder.

[0031] (2) In a tube furnace, under a nitrogen atmosphere, the temperature is increased to 1000℃ at 15℃ / min, held for 6 hours, and then the black powder is collected after cooling.

[0032] (3) The black powder was annealed in a muffle furnace at 250°C for 3 h at a heating rate of 15°C / min to obtain MnO2 / CuO-NCNF.

[0033] Example 5:

[0034] (1) Weigh 0.5g manganese nitrate hexahydrate, 0.5g copper nitrate trihydrate and 1g polyvinylpyrrolidone and dissolve them in deionized water. Stir for 60 minutes to mix evenly and dry in an oven at 100℃. Grind the dried product into powder.

[0035] (2) In a tube furnace, under a nitrogen atmosphere, the temperature is increased to 700℃ at 5℃ / min, held for 2 hours, and then the black powder is collected after cooling.

[0036] (3) The black powder was annealed in a muffle furnace at 250°C for 3 h at a heating rate of 5°C / min to obtain MnO2 / CuO-NCNF.

[0037] Example 6:

[0038] (1) Weigh 0.5g manganese nitrate hexahydrate, 0.5g copper nitrate trihydrate and 1g polyvinylpyrrolidone and dissolve them in deionized water. Stir for 60 minutes to mix evenly and dry in an oven at 100℃. Grind the dried product into powder.

[0039] (2) In a tube furnace, under a nitrogen atmosphere, the temperature is increased to 700℃ at 5℃ / min, held for 2 hours, and then the black powder is collected after cooling.

[0040] (3) The black powder was annealed in a muffle furnace at 250°C for 5 h at a heating rate of 5°C / min to obtain MnO2 / CuO-NCNF.

[0041] Example 7:

[0042] (1) Weigh 0.5g manganese nitrate hexahydrate, 0.5g copper nitrate trihydrate and 1g polyvinylpyrrolidone and dissolve them in deionized water. Stir for 30 minutes to mix evenly and dry in an oven at 80℃. Grind the dried product into powder.

[0043] (2) In a tube furnace, under a nitrogen atmosphere, the temperature is increased to 700℃ at 15℃ / min, held for 2 hours, and then the black powder is collected after cooling.

[0044] (3) The black powder was annealed in a muffle furnace at 250°C for 3 h at a heating rate of 5°C / min to obtain MnO2 / CuO-NCNF.

[0045] Example 8:

[0046] Using the MnO2 / CuO-NCNF-modified glassy carbon electrode obtained in Example 1 as the cathode and a platinum electrode as the anode, electrochemical wastewater treatment was performed.

[0047] 0.5L of organic wastewater was injected into the electrolytic cell. The initial COD of the electroplating wastewater was approximately 300mg / L, total nitrogen was 40-50mg / L, and ammonia nitrogen was 10mg / L. Electrolysis was performed for 0.5 hours. Within 30 minutes, the wastewater met the discharge standards of less than 20mg / L for COD, less than 5mg / L for total nitrogen, and less than 5mg / L for ammonia nitrogen. The degradation efficiency was as high as 93.4%.

[0048] Example 9:

[0049] Using the glassy carbon electrode modified with MnO2 / CuO-NCNF obtained in Example 3 as the cathode and a platinum electrode as the anode, electrochemical wastewater treatment was performed.

[0050] 0.5L of organic wastewater was injected into the electrolytic cell. The initial COD of the electroplating wastewater was approximately 500mg / L, total nitrogen was 50-60mg / L, and ammonia nitrogen was 15mg / L. Electrolysis was performed for 0.5 hours. Within 30 minutes, the wastewater met the discharge standards of less than 30mg / L COD, less than 5mg / L total nitrogen, and less than 5mg / L ammonia nitrogen, achieving a degradation efficiency of up to 94%.

[0051] Example 10:

[0052] An unmodified glassy carbon electrode is used as the cathode, and a platinum electrode is used as the anode for electrochemical wastewater treatment.

[0053] 0.5L of organic wastewater was injected into the electrolytic cell. The initial COD of the electroplating wastewater was approximately 300mg / L, total nitrogen was 40-50mg / L, and ammonia nitrogen was 10mg / L. Electrolysis was performed for 0.5 hours. Within 30 minutes, the corresponding discharge standards for this wastewater were approximately 240mg / L COD, 38mg / L total nitrogen, and 9mg / L ammonia nitrogen, with a degradation efficiency of 20%.

[0054] The above detailed description of a method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode with reference to the embodiments is illustrative rather than limiting. Several embodiments may be listed within the defined scope. Therefore, variations and modifications without departing from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a three-dimensional carbon-based metal oxide electrocatalytic electrode, characterized by, The preparation steps are as follows: (1) a pre-reaction mixed solution of a manganese source, a copper source and polyvinylpyrrolidone is prepared, stirred uniformly and dried to obtain a precursor, wherein the manganese source is manganese nitrate hexahydrate; the copper source is copper nitrate trihydrate, and the mass ratio of the manganese source, the copper source and polyvinylpyrrolidone is 0.3-0.8:0.3-0.8:0.8-1.5; (2) carbonization is performed by heating in a tube furnace under a nitrogen atmosphere, to obtain Mn / Cu-NCNF, wherein the heating rate of the tube furnace is 5-15 ℃ / min, the sintering temperature is 600-1000 ℃, and the holding time is 2 h; (3) annealing is performed in a muffle furnace, to obtain MnO2 / CuO-NCNF, wherein the heating rate of the muffle furnace is 5-15 ℃ / min, the annealing temperature is 250-300 ℃, and the annealing time is 3-5 hours.