Preparation and application of high-entropy alloy for catalytic ozonation and oxide of high-entropy alloy

Abstract

The invention relates to a high-entropy alloy for catalytic ozonation and an oxide catalyst thereof, the high-entropy alloy and an oxide thereof contain metal elements of Fe, Mn, Cu, Ni, Co, Mo and Ti, the proportion of the high-entropy alloy Fe (33-x) Co15Mn20Cu15Ni12Mo5Tix (x = 0-5) is 33-x: 15: 20: 15: 12: 5: x (x = 0-5), the high-entropy alloy is prepared through a water atomization method, then the high-entropy alloy oxide is prepared through high-temperature activation at 600-1000 DEG C, the activation time is 5-6 h, and the high-entropy alloy oxide is prepared through high-temperature activation. The activated catalyst has the particle size of 60-100 microns, mainly contains oxides such as Fe2O3, CoFe2O4, MnO2, FeTiO3, NiTiO3, CuFe2O4 and Fe2MoO4, is used in the field of advanced treatment of industrial wastewater, can induce ozone to generate more hydroxyl radicals (. OH), and has the advantages of high ozone utilization rate, high COD (Chemical Oxygen Demand) value removal efficiency and lower cost.

Description

Technical Field

[0001] The invention relates to a high entropy alloy for ozone catalytic oxidation and preparation and application of its oxide, belonging to the technical field of water treatment. Background Art

[0002] With the rapid development of industrialization, the amount of pollutant emissions has increased, and sewage discharge standards have become increasingly stringent. The deep treatment of industrial wastewater has become a hot topic in today's research. As an effective means of advanced oxidation, ozone oxidation technology has very strong oxidizing properties and can remove many pigments. It is increasingly used in the deep treatment of industrial biochemical tail water. The ozone catalytic oxidation process can further improve the treatment capacity of ozone oxidation and overcome the shortcomings of ozone's single selectivity and weak oxidation ability for pollutants in water. The ozone catalytic oxidation process can induce ozone to produce a large number of hydroxyl radicals through catalysts, thereby improving the oxidation capacity of the entire reaction system, shortening the reaction time, reducing operating costs, and further improving the removal rate of organic matter in sewage. The key to ozone catalytic oxidation lies in the development and utilization of catalysts.

[0003] High entropy alloy is an alloy system containing five or more metal components, with equiatomic ratio or nearly equiatomic ratio between the components and the content of each component between 5%-35%. High entropy alloy is an alloy system composed of multiple elements. High entropy alloy has many excellent properties such as mechanical properties, corrosion resistance, wear resistance and good thermal stability.

[0004] At present, most of the research on high entropy alloys is focused on their mechanical properties, but there are few reports on their use in wastewater degradation. Compared with general crystalline materials, the atomic arrangement of high entropy alloys that deviates from the equilibrium position is more conducive to the combination of surface atoms and solvent atoms to produce a reduction reaction. High entropy alloy oxides are the products of activated high entropy alloy powders. Therefore, on the premise of ensuring the formation of a simple solid solution structure of high entropy alloys, how to improve the efficiency of wastewater degradation is a problem that needs to be solved in the application of high entropy alloys and their oxides in wastewater degradation. The introduction of active metal elements has great research value for the application of high entropy alloys and their oxides. This paper focuses on the application of high entropy alloys containing active metal elements in the field of water treatment.

[0005] Combined with the ozone catalytic oxidation process, it is of certain research significance to use high entropy alloys and their oxides as catalytic materials for ozone catalytic oxidation. Summary of the invention

[0006] In view of the existing deficiencies, the present invention provides a high entropy alloy and an oxide catalyst thereof for ozone catalytic oxidation. Under weak alkaline conditions, the catalyst can induce ozone to produce a large number of hydroxyl radicals (·OH), oxidizing organic matter, bacteria, viruses, etc. in water into carbon dioxide, water and inorganic small molecules. The catalytic efficiency is high, the catalytic effect is stable, and the operating cost is reduced.

[0007] The first object of the present invention is to provide a high entropy alloy and its oxide for ozone catalytic oxidation.

[0008] Preferably according to the present invention, the high entropy alloy and its oxides contain Fe, Mn, Cu, Ni, Co, Mo, and Ti metal elements, mainly oxides such as Fe2O3, CoFe2O4, MnO2, FeTiO3, NiTiO3, CuFe2O4, and Fe2MoO4.

[0009] The present invention preferably uses low-priced FeTi40, FeMn80, FeNi50, FeMo60 ferroalloy powders, as well as Co powder and Cu powder, and uses reduced Fe powder to adjust the alloy ratio to obtain a suitable atomic ratio.

[0010] Preferably, according to the present invention, when preparing high entropy alloys and their oxides, powders are mixed according to the atomic ratio, and the designed high entropy alloy Fe(33-x)Co15Mn20Cu15Ni12Mo5Tix (x=0~5) is prepared, and the corresponding FeTi40, FeMn50, FeNi50, FeMo60, Cu, Co powders and reduced Fe powder are weighed.

[0011] Preferably according to the present invention, the activation temperature of the high entropy alloy and its oxide is 600-1000° C., and the activation time is 5-6 hours.

[0012] Preferably according to the present invention, the obtained high entropy alloy and its oxide catalyst particle size is 60 to 100 μm.

[0013] The second object of the present invention is to provide a method for preparing a high entropy alloy and its oxide for ozone catalytic oxidation.

[0014] According to the atomic ratio of Fe(33-x)Co15Mn20Cu15Ni12Mo5Tix (x=0~5), FeTi40, FeMn80, FeNi50, FeMo60, Cu powder and Co powder are weighed in weight ratio. The weighed powder is added to a ball mill. The mixed powder is mechanically ball milled for 9 hours to obtain a uniform mixed powder of 1-60μm. It is melted in a high-frequency induction metal melting furnace and a high-entropy alloy powder is obtained by high-pressure water atomization.

[0015] The high entropy alloy powder is evenly spread in a long crucible and activated at a high temperature of 600-1000°C in a muffle furnace for 5-6 hours to obtain a catalyst.

[0016] The third object of the present invention is to provide a high entropy alloy and its oxide application for ozone catalytic oxidation.

[0017] A high entropy alloy for ozone catalytic oxidation and an application of its oxide are used in the field of deep treatment of industrial wastewater, wherein the industrial wastewater includes chemical wastewater, printing and dyeing wastewater, pulping and papermaking wastewater, and pharmaceutical wastewater.

[0018] According to a preferred embodiment of the present invention, the specific application steps are as follows:

[0019] 1) Pre-treat industrial wastewater to ensure that the biochemical effluent quality reaches COD Cr ≤200mg / L, SS≤80mg / L, chromaticity≤100 times.

[0020] 2) The wastewater after pretreatment in step 1) is adjusted to pH 8-9 and introduced into a reaction tower containing a high entropy alloy and its oxide catalyst, and a certain amount of ozone gas is introduced according to the water quality to perform ozone catalytic oxidation treatment.

[0021] Preferably according to the present invention, the pretreatment in step 1) is conventional biochemical or precipitation treatment.

[0022] Preferably according to the present invention, in step 2), the amount of high entropy alloy oxide catalyst added is 60-100 g / L.

[0023] Preferably according to the present invention, in step 2), the pH value of the ozone catalytic oxidation treatment is 8-9.

[0024] The catalyst of the invention can efficiently induce ozone catalytic oxidation reaction under weak alkaline conditions, and the effluent quality meets the first-level emission standard of GB18918-2002 "Pollutant Emission Standard for Urban Sewage Treatment Plants". The beneficial effects of the present invention are as follows:

[0025] 1. The catalyst material of the present invention adopts cheap iron alloy and non-precious metal materials. The high entropy alloy powder prepared by high-frequency induction metal melting furnace and water atomization method has low cost and is suitable for the preparation of large-scale alloy powder catalysts.

[0026] 2. The catalyst of the present invention has a synergistic effect between the various metal elements, which greatly improves the catalytic efficiency of the catalyst, can induce ozone to produce more hydroxyl radicals (·OH), so that the ozone utilization rate is higher, the COD value removal efficiency is higher, the cost is low, the process flow and operation are simple, and it is easy to realize industrialization.

[0027] 3. The optimal pH value of the catalyst of the present invention during ozone catalytic oxidation is 8-9, the reaction conditions are mild, the pH value of the effluent is neutral, and it can be directly discharged in compliance with the standards.

[0028] 4. The catalyst of the present invention has high reaction efficiency, long service life, economy, and convenience in use. The effluent effect is stable and up to standard, no chemical sludge is generated, and the cost of chemical sludge treatment is saved. This catalyst is easy to achieve solid-liquid separation.

[0029] 5. After deep treatment with the catalyst of the present invention, the effluent quality meets the first-level emission standard of GB18918-2002 "Pollutant Emission Standard for Urban Sewage Treatment Plants". BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The X-ray diffraction (XRD) spectrum of the unactivated catalyst prepared in Example 1. The prepared catalyst is mainly composed of body-centered cubic BCC phase solid solution, accompanied by a small amount of face-centered cubic solid solution FCC phase.

[0031] Figure 2 The X-ray diffraction (XRD) spectrum of the catalyst activated at 1000°C prepared in Example 1. The prepared catalyst forms high entropy alloy metal oxides and composite oxides after being activated at 1000°C. They are mainly present in oxides such as Fe2O3, CoFe2O4, MnO2, FeTiO3, NiTiO3, CuFe2O4, and Fe2MoO4.

[0032] Figure 3 This is a SEM microscopic morphology of the catalyst prepared in Example 1 after activation at 1000°C.

[0033] Figure 4 This is a partially enlarged SEM microscopic morphology of the catalyst prepared in Example 1 after activation at 1000°C. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto.

[0035] The raw materials in the examples are all commercially available products. Embodiment 1:

[0036] A method for preparing a high entropy alloy and an oxide catalyst thereof for ozone catalytic oxidation, the specific experimental steps are as follows:

[0037] According to the atomic ratio of Fe28Co15Mn20Cu15Ni12Mo5Ti5, FeTi40, FeMn80, FeNi50, FeMo60, Cu powder and Co powder are weighed in a weight ratio of 600:1375:1409:800:953:839. The weighed powder is added to a ball mill. The mixed powder is mechanically ball milled for 9 hours to obtain a uniform mixed powder of 50-60μm. It is melted in a high-frequency induction metal melting furnace and a high-entropy alloy powder is produced by high-pressure water atomization.

[0038] The high entropy alloy powder was evenly spread in a long crucible and activated at 1000°C in a muffle furnace for 5 hours to obtain an activated catalyst. Example 2

[0039] A method for preparing a high entropy alloy and an oxide catalyst thereof for ozone catalytic oxidation is the same as that in Example 1, except that the high entropy alloy powder is evenly spread in a long crucible and activated at 800° C. for 5 hours in a muffle furnace to obtain an activated catalyst. Example 3

[0040] A method for preparing a high entropy alloy and an oxide catalyst thereof for ozone catalytic oxidation is the same as that in Example 1, except that the high entropy alloy powder is evenly spread in a long crucible and activated at 600° C. for 5 hours in a muffle furnace to obtain an activated catalyst. Example 4

[0041] A method for preparing a high entropy alloy and an oxide catalyst thereof for ozone catalytic oxidation, comprising the following steps:

[0042] According to the atomic ratio of Fe33Co15Mn20Cu15Ni12Mo5, FeMn80, FeNi50, FeMo60, Cu powder, Co powder, Fe powder are weighed in a weight ratio of 1375:1409:800:953:839:563. The weighed powder is added to a ball mill. The mixed powder is mechanically ball milled for 9 hours to obtain a uniform mixed powder of 50-60μm. It is melted in a high-frequency induction metal melting furnace and a high-entropy alloy powder is produced by high-pressure water atomization.

[0043] The high entropy alloy powder was evenly spread in a long crucible and activated at 1000°C in a muffle furnace for 5 hours to obtain an activated catalyst. Comparative Example 1

[0044] A method for preparing a high entropy alloy and an oxide catalyst thereof for ozone catalytic oxidation is the same as that in Example 1, except that the high entropy alloy powder is evenly spread in a long crucible and activated at 400° C. in a muffle furnace for 5 hours to obtain an activated catalyst. Comparative Example 2

[0045] A method for preparing a high entropy alloy catalyst for ozone catalytic oxidation is the same as that in Example 1, except that the catalyst is not activated at high temperature. Application Experiment Example

[0046] The biochemically treated chemical park wastewater (COD of 167 mg / L, pH of 8.2) was divided into 8 parts and introduced into the ozone catalytic oxidation system respectively, and 8 treatments were performed in parallel. Treatments 1-4 were respectively adding 80 g / L of the catalyst of Examples 1-4 to the system, passing 120 mg / L of ozone, and reacting for 30 minutes. Treatments 5-6 were respectively adding the same amount of the catalyst of Comparative Examples 1-2 to the system, passing 120 mg / L of ozone, and reacting for 30 minutes. Treatment 7 was not adding catalyst, passing 120 mg / L of ozone, and reacting for 30 minutes. Treatment 8 was adding only the catalyst of Example 1, not passing ozone, and reacting for 30 minutes. The addition amount of the catalyst for the above treatments was the same, and the COD and chromaticity in the supernatant were detected by standing. The test results are shown in Table 1 below.

[0047] The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some technical features of the present invention are modified without departing from the essential spirit of the technical solution of the present invention. These changes should be included in the scope of the technical solution claimed for protection of the present invention.

Claims

1. A high entropy alloy and its oxide catalyst for ozone catalytic oxidation, wherein the high entropy alloy and its oxide contain Fe, Mn, Cu, Ni, Co, Mo, and Ti metal elements, the high entropy alloy Fe(33-x)Co15Mn20Cu15Ni12Mo5Tix(x=0-5) has a ratio of (33-x):15:20:15:12:5:x(x=0-5), and the oxides mainly include Fe2O3, CoFe2O4, MnO2, FeTiO3, NiTiO3, CuFe2O4, and Fe2MoO4.

2. The high entropy alloy and oxide catalyst thereof according to claim 1, characterized in that: Low-priced FeTi40, FeMn80, FeNi50, FeMo60 ferroalloy powders, as well as Co and Cu powders are selected, and the alloy ratio is adjusted using reduced Fe powder to obtain a suitable atomic ratio.

3. The high entropy alloy and oxide catalyst thereof according to claim 1, characterized in that: The particle size is 60-100μm.

4. A high entropy alloy and its oxide catalyst for ozone catalytic oxidation, comprising the following steps: 1) FeTi40, FeMn80, FeNi50, FeMo60, Cu powder and Co powder were weighed according to the atomic ratio of high entropy alloy, the weighed powders were added into a ball mill, the mixed powders were mechanically ball milled for 9 hours to obtain a uniform mixed powder of 1-60 μm, the mixed powders were put into a high-frequency induction metal melting furnace for melting, and high entropy alloy powders were prepared by high-pressure water atomization; 2) High entropy alloy powder is evenly spread in a long crucible and activated at 600-1000°C in a muffle furnace for 5-6 hours to obtain a catalyst.

5. The preparation method according to claim 4, characterized in that: The high entropy alloy Fe(33-x)Co15Mn20Cu15Ni12Mo5Tix (x=0~5) was prepared by water atomization method.

6. The preparation method according to claim 4, characterized in that: Activation time: 5-6h.

7. The preparation method according to claim 4, characterized in that: Activated by high temperature of 600-1000℃.

8. An application of the high entropy alloy and its oxide catalyst as described in any one of claims 1 to 3, in the field of deep treatment of industrial wastewater, wherein the industrial wastewater includes chemical wastewater, printing and dyeing wastewater, pulp and paper making wastewater, and pharmaceutical wastewater.

9. The use according to claim 8, characterized in that: The specific application method is as follows: pre-treat the industrial wastewater first, and the biochemical effluent water quality reaches COD Cr ≤200mg / L, SS≤80mg / L, chromaticity≤100 times; the pretreated wastewater is adjusted to pH 8-9, introduced into a reaction tower containing a high entropy alloy and its oxide catalyst, and a certain amount of ozone gas is introduced for ozone catalytic oxidation treatment; the amount of catalyst added is 60-100g / L.

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