Aluminum-based metal catalyst and its preparation method and application

Abstract

The present invention discloses an aluminum-based metal catalyst, its preparation method and application. Through simple and low-cost smelting, casting and crushing processes, a novel and efficient aluminum-based metal catalyst is prepared, significantly improving the degradation efficiency of sewage pollutants in the persulfate advanced oxidation system. Its degradation efficiency and catalyst cost are both lower than those of conventional Fe-based catalysts, breaking through the problem of reduced catalytic efficiency caused by the inactivation of Fe<supgt;2+< / supgt; in conventional Fe-based catalysts. The present invention realizes the high activity of catalytic ions in the reaction process through a multi-element alloy composition system, which is the future development direction of catalysts for the persulfate advanced oxidation system.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to an aluminum-based metal catalyst and a preparation method and application thereof. Background Art

[0002] Printing and dyeing wastewater is a mixed wastewater of various wastewaters generated by the reprocessing of natural and artificial fiber materials by printing and dyeing factories, wool spinning mills, knitting mills, etc. It mainly contains impurities such as dyes, pulps, additives, oils, acids and alkalis, fiber impurities and inorganic salts. It has the characteristics of complex composition, high content of difficult-to-degrade organic pollutants, high chroma, high chemical oxygen demand, high biochemical oxygen demand, high alkalinity, high toxicity, large water volume, and large water quality changes. Nowadays, the problem of dye pollution in printing and dyeing wastewater is becoming increasingly serious and has become an environmental challenge that needs to be solved urgently. Therefore, it is particularly important to develop technologies for efficient degradation of dye pollutants, which requires the development of catalysts with better catalytic performance for efficient degradation. Current research work mainly focuses on the preparation of persulfate-activated catalysts using various strategies such as heat treatment, base catalysis, radiation induction, transition metal doping and carbon material composites, thereby realizing advanced oxidation degradation of wastewater. However, these preparation strategies generally face the difficulties of complex and cumbersome preparation conditions, limited catalyst yield and potential side effects caused by harsh chemical conditions such as alkalinity, which to a certain extent restricts their wide application and performance optimization. Summary of the invention

[0003] In order to solve the problems of insufficient catalyst activation efficiency and high cost in the prior art, the purpose of the present invention is to provide an aluminum-based metal catalyst and a preparation method and application thereof. The catalyst can efficiently activate the persulfate oxidant and improve the degradation efficiency of pollutants. At the same time, the preparation process of the catalyst is low in cost and can achieve high yield.

[0004] The above object of the present invention is achieved through the following technical solutions:

[0005] The first aspect of the present invention provides a method for preparing an aluminum-based metal catalyst, comprising the following steps:

[0006] (1) placing an aluminum alloy in a resistance furnace for melting, the aluminum alloy comprising the following components in percentage by mass: Si 6-12%, Fe 0.3-1.2%, Cu 0-3%, Mg 0-0.5%, Mn 0-0.5%, other alloying elements less than 0.5%, and the remainder being Al;

[0007] (2) Testing the element composition of the molten aluminum alloy, and adding Al-Fe master alloy and Al-Mn master alloy according to the test results to adjust the composition so that the Fe+Mn content in the aluminum alloy melt is 1.0-3.0%, and the mass ratio of Fe to Mn is (0.1-2):1;

[0008] (3) The temperature of the aluminum alloy melt after the composition adjustment is adjusted to 610-660°C, and the temperature is kept for 0.5-3 hours. Then, the aluminum alloy melt at the lower 1 / 4-1 / 2 height of the resistance furnace is cast, and the obtained ingot is crushed to obtain the aluminum-based metal catalyst.

[0009] The aluminum-based metal catalyst prepared by traditional metal smelting and casting in the present invention shows more excellent catalytic degradation performance than commercial catalysts such as iron powder, and has low preparation cost and high preparation yield, and can be used as a more efficient dye wastewater catalytic degradation agent, improving degradation efficiency while effectively reducing the preparation cost of the catalyst. Since the aluminum alloy melt is in the process of heat preservation, metals such as Fe, Mn, and Cu with a density greater than Al will undergo gravity sedimentation during the melt heat preservation process, resulting in higher Fe, Mn, and Cu content in the lower part than in the upper part, and also higher than the average content of Fe, Mn, and Cu elements in the melt, and the distribution law of each metal element is consistent after gravity sedimentation, so the aluminum alloy melt at the lower 1 / 4-1 / 2 height of the resistance furnace after heat preservation for 0.5-3 h is selected, so that the content of each metal element in the catalyst finally obtained is within the range that can achieve catalytic degradation performance.

[0010] Furthermore, in step (1), the aluminum alloy is Al-Si aluminum alloy scrap. Al-Si aluminum alloy scrap is the scrap generated during the production, manufacturing, and use of Al-Si aluminum alloy, and may come from scraps, waste products, or recycled waste products in the manufacturing process of various aluminum alloy products. During the recycling and reuse process of Al-Si aluminum alloy scrap, other metal impurities may be mixed in; during the recycling and smelting process, due to high temperature and chemical reactions, some alloy elements may be volatilized or oxidized, causing the alloy composition to deviate from the original design.

[0011] Furthermore, in step (1), the aluminum alloy may be Al-Si aluminum alloy waste such as A356, A380, ADC12, etc.

[0012] In a specific embodiment, in step (1), the aluminum alloy is placed in a resistance furnace and melted at 730-750°C.

[0013] Furthermore, in step (2), the aluminum alloy is melted and then kept warm for 0.5-1 h before elemental composition testing is performed.

[0014] Preferably, in step (2), the Fe+Mn content in the aluminum alloy melt is 1.0-2.8%, and the mass ratio of Fe to Mn is (0.5-2):1. The effective elements in the catalyst are mainly Fe and Mn elements, and their content composition depends on the regulation of the Fe and Mn contents in the aluminum alloy melt composition regulation link, so that after the ingot formed by the aluminum alloy melt at the lower 1 / 4-1 / 2 height of the resistance furnace is made into powder, the Fe and Mn contents in the powder composition are within a reasonable range, and the regulation and melt insulation process conform to the principles of material metallurgy.

[0015] Furthermore, in step (3), the obtained ingot is crushed into powder with a particle size of 10-1500 microns to obtain the aluminum-based metal catalyst.

[0016] In a specific embodiment, in step (3), the cast ingot is cut into small pieces with a size of 2-5 mm and crushed using a ball mill to crush the ingot into powder with a particle size of 10-1500 microns to obtain the aluminum-based metal catalyst.

[0017] Preferably, the powder has a particle size of 100-800 microns.

[0018] The second aspect of the present invention provides an aluminum-based metal catalyst prepared by the method described in the first aspect.

[0019] The third aspect of the present invention provides an application of the aluminum-based metal catalyst described in the second aspect in sewage treatment.

[0020] The aluminum-based metal catalyst provided by the invention can be used as a persulfate advanced oxidation system catalyst in the field of printing and dyeing wastewater treatment.

[0021] Furthermore, the persulfate is preferably peroxydisulfate.

[0022] Furthermore, the specific method for treating the printing and dyeing wastewater is: adding aluminum-based metal catalyst and persulfate to the printing and dyeing wastewater.

[0023] Furthermore, the concentration of the aluminum-based metal catalyst in the printing and dyeing wastewater is 0.1-1 g / L, and the concentration of the persulfate is 1-3 mM.

[0024] Furthermore, the dye in the printing and dyeing wastewater is selected from one or more of rhodamine B, methyl blue, methylene blue, methyl orange, acid orange II, brilliant red 3BN and brilliant black BN.

[0025] Beneficial effects of the present invention:

[0026] The present invention prepares a new type of efficient aluminum-based metal catalyst through a simple and low-cost smelting, casting and crushing process, which significantly improves the degradation efficiency of sewage pollutants by the persulfate advanced oxidation system. The degradation efficiency and catalyst cost are lower than those of conventional Fe-based catalysts, breaking through the Fe 2+ The present invention achieves high activity of catalytic ions in the reaction process through a multi-element alloy component system, which is the future development direction of persulfate advanced oxidation system catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the SEM image of the aluminum-based metal catalyst prepared in Example 1.

[0028] Figure 2 This is the SEM image of the aluminum-based metal catalyst prepared in Example 2.

[0029] Figure 3 This is the SEM image of the aluminum-based metal catalyst prepared in Example 3. DETAILED DESCRIPTION

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0033] The present invention provides a method for preparing an aluminum-based metal catalyst, comprising the following steps:

[0034] (1) placing an aluminum alloy in a resistance furnace for melting, the aluminum alloy comprising the following components in percentage by mass: Si 6-12%, Fe 0.3-1.2%, Cu 0-3%, Mg 0-0.5%, Mn 0-0.5%, other alloying elements less than 0.5%, and the remainder being Al;

[0035] (2) Testing the element composition of the molten aluminum alloy, and adding Al-Fe master alloy and Al-Mn master alloy according to the test results to adjust the composition so that the Fe+Mn content in the aluminum alloy melt is 1.0-3.0%, and the mass ratio of Fe to Mn is (0.1-2):1;

[0036] (3) The temperature of the aluminum alloy melt after the composition adjustment is adjusted to 610-660°C, and the temperature is kept for 0.5-3 hours. Then, the aluminum alloy melt at the lower 1 / 4-1 / 2 height of the resistance furnace is cast, and the obtained ingot is crushed to obtain the aluminum-based metal catalyst.

[0037] In a specific embodiment, the preparation method comprises the following steps:

[0038] (1) Al-Si aluminum alloy scraps such as A356, A380, and ADC12 are placed in a resistance furnace and melted at 730-750 °C. The aluminum alloy scraps include the following components in mass percentage: Si 6-12%, Fe 0.3-1.2%, Cu 0-3%, Mg0-0.5%, Mn 0-0.5%, other alloying elements less than 0.5%, and the rest is Al.

[0039] (2) After melting the aluminum alloy scrap, keep it warm for 0.5-1 h, and then conduct elemental composition testing. According to the test results, Al-Fe master alloy and Al-Mn master alloy are added to adjust the composition so that Fe+Mn in the aluminum alloy melt is 1.0-3.0%, and the mass ratio of Fe to Mn is (0.1-2):1.

[0040] (3) The temperature of the aluminum alloy melt after the composition adjustment is adjusted to 610-660 °C, and the temperature is kept for 0.5-3 h. Then, the aluminum alloy melt at the lower 1 / 4-1 / 2 height of the resistance furnace is poured out from the bottom for casting to form an ingot.

[0041] (4) Cutting the cast ingot into small pieces with a size of 2-5 mm and crushing them using a ball mill, crushing the ingot into powder with a particle size of 10-1500 microns to obtain the aluminum-based metal catalyst.

[0042] The dye wastewater (sewage) in the following examples and comparative examples is simulated dye wastewater containing 10 mg / L of Acid Orange II (pollutant).

[0043] Example 1

[0044] A method for preparing an aluminum-based metal catalyst comprises the following steps:

[0045] (1) A356 aluminum alloy scrap is placed in a resistance furnace and melted at 730° C. The A356 aluminum alloy scrap includes the following components in mass percentage: Si 6.8%, Fe 0.3%, Cu 0.05%, Mg 0.28%, Mn 0.05%, other alloying elements less than 0.5%, and the rest is Al.

[0046] (2) After the aluminum alloy scrap is melted, it is kept warm for 0.5 h and then the elemental composition is tested. According to the test results, Al-Fe master alloy (Fe 5%, the rest is Al) and Al-Mn master alloy (Mn 5%, the rest is Al) are added to adjust the composition so that the aluminum alloy melt contains Fe+Mn 1.0% and the mass ratio of Fe to Mn is 0.5:1.

[0047] (3) The temperature of the aluminum alloy melt after the composition adjustment is adjusted to 610 °C and kept at this temperature for 0.5 h. Then, the melt at the lower 1 / 4 height of the resistance furnace is poured out from the bottom for casting to form an ingot.

[0048] (4) The cast ingot is cut into small pieces with a size of 2 mm and crushed using a ball mill to crush the ingot into powder with a particle size of 100-300 microns to obtain the aluminum-based metal catalyst.

[0049] The scanning electron microscope (SEM) image of the aluminum-based metal catalyst prepared in Example 1 is as follows: Figure 1 As shown, the elemental composition of the aluminum-based metal catalyst prepared in Example 1 was tested using a scanning electron microscope-energy dispersive spectrometer (SEM-EDS). The test results are shown in Table 1:

[0050] Table 1

[0051]

[0052] Among them, O element is caused by oxidation caused by ball milling in air, and the content of Cu element and Mg element is too small to be detected. Si element forms a compound in the ingot and is formed at the grain boundary position, and has a certain degree of inhomogeneity after forming the powder.

[0053] The aluminum-based metal catalyst and peroxydisulfate oxidant prepared in Example 1 were added to the dye wastewater to initiate the reaction, so that the concentration of the aluminum-based metal catalyst in the dye wastewater was 0.3 g / L, the concentration of peroxydisulfate was 1 mM, and the stirring speed during the reaction was 200 r•min -1 After 0.5 h, a certain amount of reaction solution was taken and analyzed by ultraviolet spectrophotometry to analyze the characteristic peaks of the dye. The changes in the content of pollutants in the sewage were measured and the pollutant removal effect was found to be 90%.

[0054] Example 2

[0055] A method for preparing an aluminum-based metal catalyst comprises the following steps:

[0056] (1) A380 aluminum alloy scrap is placed in a resistance furnace and melted at 730° C. The A380 aluminum alloy scrap includes the following components in mass percentage: Si 10.7%, Fe 0.7%, Cu 1.8%, Mg 0.3%, Mn 0.3%, other alloy elements content is less than 0.5%, and the rest is Al.

[0057] (2) The aluminum alloy scrap was melted and kept warm for 1 h, and then the elemental composition was tested. According to the test results, Al-Fe master alloy (Fe 5%, the rest is Al) and Al-Mn master alloy (Mn 5%, the rest is Al) were added to adjust the composition so that the aluminum alloy melt contained Fe+Mn 2.2% and the mass ratio of Fe to Mn was 1.2:1.

[0058] (3) The temperature of the aluminum alloy melt after the composition adjustment is adjusted to 630 °C and kept at this temperature for 1 h. Then, the melt at the lower 1 / 3 height of the resistance furnace is poured out from the bottom for casting to form an ingot.

[0059] (4) The cast ingot is cut into small pieces with a size of 2 mm and crushed using a ball mill to crush the ingot into powder with a particle size of 200-400 μm to obtain the aluminum-based metal catalyst.

[0060] The SEM image of the aluminum-based metal catalyst prepared in Example 2 is as follows: Figure 2 As shown, the elemental composition of the aluminum-based metal catalyst prepared in Example 2 was tested by scanning electron microscope-energy dispersive spectrometer (SEM-EDS), and the test results are shown in Table 2:

[0061] Table 2

[0062]

[0063] Among them, O element is caused by oxidation caused by ball milling in air, and Mg element content is too low to be detected. Si element forms compounds in the ingot and forms at the grain boundary position, and has a certain degree of inhomogeneity after forming powder.

[0064] The aluminum-based metal catalyst and peroxydisulfate oxidant prepared in Example 2 were added to the dye wastewater to initiate the reaction, so that the concentration of the aluminum-based metal catalyst in the dye wastewater was 0.5 g / L, the concentration of peroxydisulfate was 2 mM, and the stirring speed during the reaction was 300 r•min -1 After 0.5 h, a certain amount of reaction solution was taken to measure the change in the content of pollutants in the sewage, and the pollutant removal effect was found to be 93%.

[0065] Example 3

[0066] A method for preparing an aluminum-based metal catalyst comprises the following steps:

[0067] (1) ADC12 aluminum alloy scrap is placed in a resistance furnace and melted at 730° C. The ADC12 aluminum alloy scrap includes the following components in mass percentage: Si 9.8%, Fe 0.5%, Cu 1.2%, Mg 0.2%, Mn 0.5%, other alloy elements content is less than 0.5%, and the rest is Al.

[0068] (2) The aluminum alloy scrap was melted and kept warm for 1 h, and then the elemental composition was tested. According to the test results, Al-Fe master alloy (Fe 5%, the rest is Al) and Al-Mn master alloy (Mn 5%, the rest is Al) were added to adjust the composition so that the aluminum alloy melt contained Fe+Mn 3.0% and the mass ratio of Fe to Mn was 2:1.

[0069] (3) The temperature of the aluminum alloy melt after the composition adjustment is adjusted to 660 °C and kept at this temperature for 3 h. Then, the melt at the lower 1 / 2 height of the resistance furnace is poured out from the bottom for casting to form an ingot.

[0070] (4) The cast ingot is cut into small pieces with a size of 2 mm and crushed using a ball mill to crush the ingot into powder with a particle size of 400-800 μm to obtain the aluminum-based metal catalyst.

[0071] The SEM image of the aluminum-based metal catalyst prepared in Example 3 is as follows: Figure 3 As shown, the elemental composition of the aluminum-based metal catalyst prepared in Example 3 was tested by scanning electron microscope-energy dispersive spectrometer (SEM-EDS), and the test results are shown in Table 3:

[0072] Table 3

[0073]

[0074] Among them, O element is caused by oxidation caused by ball milling in air, and Mg element content is too low to be detected. Si element forms compounds in the ingot and forms at the grain boundary position, and has a certain degree of inhomogeneity after forming powder.

[0075] The aluminum-based metal catalyst and peroxydisulfate oxidant prepared in Example 3 were added to the dye wastewater to initiate the reaction, so that the concentration of the aluminum-based metal catalyst in the dye wastewater was 1 g / L, the concentration of peroxydisulfate was 3 mM, and the stirring speed during the reaction was 500 r•min -1After 0.5 h, a certain amount of reaction solution was taken to measure the change in the content of pollutants in the sewage, and the pollutant removal effect was found to be 95%.

[0076] Comparative Example 1

[0077] Pure aluminum metal powder with a purity of 99.9% and peroxydisulfate oxidant were added to the dye wastewater to initiate the reaction, so that the concentration of pure aluminum metal powder in the dye wastewater was 0.5 g / L and the concentration of peroxydisulfate was 1 mM. The stirring speed during the reaction was 500 r•min -1 After 0.5 h, a certain amount of reaction solution was taken to measure the change in the content of pollutants in the sewage, and the pollutant removal effect was found to be 45%.

[0078] Comparative Example 2

[0079] Aluminum alloy powder (Si 9.8%, Fe 0.5%, the rest Al) and peroxydisulfate oxidant were added to the dye wastewater to initiate the reaction, so that the concentration of aluminum alloy powder in the dye wastewater was 0.5 g / L, the concentration of peroxydisulfate was 1 mM, and the stirring speed during the reaction was 500 r•min -1 After 0.5 h, a certain amount of reaction solution was taken to measure the change in the content of pollutants in the sewage, and the pollutant removal effect was found to be 50%.

[0080] Comparative Example 3

[0081] Aluminum alloy powder (Si 9.8%, Fe 0.1%, Mn 0.1%, the rest is Al) and peroxydisulfate oxidant were added to the dye wastewater to initiate the reaction. The concentration of aluminum alloy powder in the dye wastewater was 0.5 g / L, the concentration of peroxydisulfate was 1 mM, and the stirring speed during the reaction was 500 r•min -1 After 0.5 h, a certain amount of reaction solution was taken to measure the change in the content of pollutants in the sewage, and the pollutant removal effect was found to be 53%.

[0082] Comparative Example 4

[0083] Aluminum alloy powder (Si 9.8%, Fe 2.1%, Mn 1.2%, the rest is Al) and peroxydisulfate oxidant were added to the dye wastewater to initiate the reaction. The concentration of aluminum alloy powder in the dye wastewater was 0.5 g / L, the concentration of peroxydisulfate was 1 mM, and the stirring speed during the reaction was 500 r•min -1 After 0.5 h, a certain amount of reaction solution was taken to measure the change in the content of pollutants in the sewage, and the pollutant removal effect was found to be 57%.

[0084] Comparative Example 5

[0085] Fe-based metal powder (Fe3O4 powder) and peroxydisulfate oxidant were added to the dye wastewater to initiate the reaction, so that the concentration of Fe-based metal powder in the dye wastewater was 0.5 g / L, the concentration of peroxydisulfate was 1 mM, and the stirring speed during the reaction was 500 r•min -1 After 0.5 h, a certain amount of reaction solution was taken to measure the change in the content of pollutants in the sewage, and the pollutant removal effect was found to be 65%.

[0086] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art should understand that other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing an aluminum-based metal catalyst, characterized in that: The following steps are involved: (1) placing an aluminum alloy in a resistance furnace for melting, the aluminum alloy comprising the following components in percentage by mass: Si 6-12%, Fe 0.3-1.2%, Cu 0-3%, Mg 0-0.5%, Mn 0-0.5%, other alloying elements less than 0.5%, and the remainder being Al; (2) Testing the element composition of the molten aluminum alloy, and adding Al-Fe master alloy and Al-Mn master alloy according to the test results to adjust the composition so that the Fe+Mn content in the aluminum alloy melt is 1.0-3.0%, and the mass ratio of Fe to Mn is (0.1-2):1; (3) The temperature of the aluminum alloy melt after the composition adjustment is adjusted to 610-660°C, and the temperature is kept for 0.5-3 hours. Then, the aluminum alloy melt at the lower 1 / 4-1 / 2 height of the resistance furnace is cast, and the obtained ingot is crushed to obtain the aluminum-based metal catalyst.

2. The preparation method according to claim 1, characterized in that: In step (1), the aluminum alloy is Al-Si aluminum alloy waste.

3. The preparation method according to claim 1, characterized in that In step (1), the aluminum alloy is placed in a resistance furnace and melted at 730-750°C.

4. The preparation method according to claim 1, characterized in that: In step (3), the obtained ingot is crushed into powder with a particle size of 10-1500 microns to obtain the aluminum-based metal catalyst.

5. An aluminum-based metal catalyst prepared by the method according to any one of claims 1 to 4.

6. Use of the aluminum-based metal catalyst according to claim 5 in sewage treatment.

7. The use according to claim 6, characterized in that: The aluminum-based metal catalyst is used as a persulfate advanced oxidation system catalyst in the field of printing and dyeing wastewater treatment.

8. The use according to claim 7, characterized in that: The specific method for treating the printing and dyeing wastewater is: adding the aluminum-based metal catalyst and persulfate into the printing and dyeing wastewater.

9. The use according to claim 8, characterized in that The concentration of the aluminum-based metal catalyst in the printing and dyeing wastewater is 0.1-1 g / L, and the concentration of the persulfate is 1-3 mM.

10. The use according to claim 7, characterized in that: The dye in the printing and dyeing wastewater is selected from one or more of rhodamine B, methyl blue, methylene blue, methyl orange, acid orange II, brilliant red 3BN and brilliant black BN.

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