Application of FeMnxCrNi High-entropy Alloy in Degradation of Azo Dye Wastewater

Abstract

A FeMn x The application of CrNi-based high-entropy alloys in the degradation of azo dye wastewater belongs to the field of wastewater treatment technology. It aims to provide a more efficient and lower-cost solution for treating wastewater containing azo dyes, specifically for the degradation of FeMn in azo dye wastewater. x CrNi-based high-entropy alloys are micron-sized powders and / or fibers, and FeMn... x The concentration of CrNi-based high-entropy alloy micron-sized powder and / or fibers in azo dye wastewater is greater than 3 g / L. The FeMn provided by this invention... x In CrNi-based high-entropy alloy micron-sized powders and / or fibers, active zero-valent metal elements destroy the "-N=N-" groups in organic synthetic dyes through redox reactions, significantly improving degradation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a FeMn... x Application of CrNi-based high-entropy alloys in the degradation of azo dye wastewater. Background Technology

[0002] Water covers more than 70% of the Earth's surface and is an essential element for life. However, for humans, most of the Earth's water is either unusable or difficult to extract. Currently, usable water resources (such as river water, freshwater, lake water, and shallow groundwater) account for only 0.007% of the global water volume. In recent years, with rapid socio-economic development, limited freshwater resources have also been severely polluted. Compared to other wastewater, industrial wastewater has a more complex composition and larger discharge volume, causing serious harm to the environment. Dyeing and printing wastewater accounts for about 10% of the total industrial wastewater discharge. Due to its large discharge volume and severe pollution, it is difficult to treat effectively. Therefore, the treatment of dyeing and printing wastewater has always been one of the important problems that researchers urgently need to solve.

[0003] Azo dyes are a widely used class of synthetic dyes, accounting for over 60% of global dye production. They are characterized by their vibrant colors and low cost, and are widely used in the textile, printing and dyeing, and cosmetic industries. It has been reported that only 45%-47% of organic dyes are biodegradable and soluble in water, while azo dyes contain azo bonds (-N=N-) in their structure. This structure gives them high chemical stability and resistance to biodegradation, making them a crucial area requiring urgent attention.

[0004] Currently, the main methods for treating azo dye wastewater include physical, chemical, and biological methods. However, these methods have certain limitations: physical methods usually require high-cost materials and complex operating processes, and the regeneration and treatment of adsorbents are also a challenge; although chemical methods have high degradation efficiency, they often require the use of large amounts of chemical reagents, which may lead to secondary pollution; biological methods are limited by the degradation capacity of microorganisms and environmental conditions, resulting in lower treatment efficiency.

[0005] High-entropy alloys are a new type of alloy material, typically composed of four or more elements with similar molar fractions (usually between 5% and 35%). The high mixing entropy of high-entropy alloys promotes the formation of simple solid solution phases, such as face-centered cubic (FCC) and body-centered cubic (BCC). This multi-element characteristic results in unique physical and chemical properties, such as high hardness, high strength, excellent corrosion resistance, and good catalytic performance. Multiple studies have shown that high-entropy alloy powders exhibit higher reaction efficiency in the degradation of azo dyes than commercial zero-valent iron powders. Therefore, developing high-entropy alloys as catalysts for the degradation of azo dyes has significant scientific and practical value.

[0006] In conclusion, the study of the degradation performance of high-entropy alloy powder on azo dyes is not only of significant scientific importance, but also has practical application value in the fields of environmental protection and materials science. Developing high-entropy alloy catalysts can provide a more efficient and cost-effective solution for the treatment of azo dye wastewater. Summary of the Invention

[0007] The main objective of this invention is to overcome the shortcomings of the prior art and provide a FeMn x The application of CrNi-based high-entropy alloys in the degradation of azo dye wastewater shows that the high-entropy alloy powder and / or microfilaments exhibit a particularly strong degradation ability for azo dye wastewater, and can be recycled, thus broadening the application range of high-entropy alloys.

[0008] This invention is achieved through the following technical solution: FeMn x Application of CrNi-based high-entropy alloys in the degradation of azo dye wastewater, including the use of FeMn in the degradation of azo dye wastewater. x CrNi-based high-entropy alloys are micron-sized powders and / or fibers (micron-sized powders and fibers are mixed in any weight ratio), and FeMn x The concentration of CrNi-based high-entropy alloy micron-sized powder and / or fibers in azo dye wastewater is greater than 3 g / L.

[0009] Furthermore, the FeMn x The atomic ratio of Fe, Mn, Cr, and Ni in the micron-sized CrNi-based high-entropy alloy powder is 1:(0.1, 0.15, 0.2, 0.25):1:1; the FeMn... x The atomic ratio of Fe, Mn, Cr, Ni, and Mo in the micron-sized fibers of CrNi-based high-entropy alloys is 40:19:20:20:1.

[0010] Furthermore, the organic dye with azo bonds in the azo dye wastewater is Direct Blue 6 dye (DB6).

[0011] Furthermore, the concentration of the azo dye wastewater to be degraded is 20-100 mg / L, the pH value of the azo dye wastewater is 3-7, and the degradation temperature is room temperature (25 ℃).

[0012] Furthermore, FeMn was used x The degradation of azo dye wastewater by CrNi-based high-entropy alloy micron-sized powder and / or fibers includes the following steps:

[0013] S1, FeMn xMicron-sized powder and / or fibers of CrNi-based high-entropy alloys were added to azo dye wastewater, followed by mechanical stirring at a speed of 200-600 rpm for 60 minutes to ensure FeMn x CrNi-based high-entropy alloy micron-sized powder and / or fibers are uniformly dispersed in azo dye wastewater;

[0014] After the degradation of S2 and azo dye wastewater is complete, FeMn x CrNi-based high-entropy alloy micron-sized powder and / or fibers are recycled and reused.

[0015] Furthermore, in step S1, before degradation, a 10 mmol / L H2O2 solution is added to the azo dye wastewater as an oxidant for the reaction.

[0016] Furthermore, the FeMn x The preparation method of CrNi-based high-entropy alloy micron-sized powder includes the following steps:

[0017] First, micron-sized Fe, Mn, Cr, and Ni elemental powders (purity > 99%) were weighed out according to an atomic ratio of 1:(0.1, 0.15, 0.2, or 0.25):1:1, and mixed and ground evenly in an agate mortar. Then, stainless steel grinding balls and the mixed metal powder were weighed out according to a ball-to-powder ratio of 15:1, placed in a stainless steel ball mill jar, and ball-milled using a high-energy planetary ball mill under argon protection at a speed of 300 r / min for 60 h. Anhydrous ethanol was added as a grinding medium during the ball milling process to prevent the metal elements from cold-welding to the inner wall of the ball mill jar due to excessive energy during grinding. Finally, the high-entropy alloy powder was removed after ball milling and dried in a vacuum drying oven to obtain FeMn for degrading azo dye wastewater. x CrNi-based high-entropy alloy micron-sized powder.

[0018] Furthermore, the FeMn x The preparation method of CrNi-based high-entropy alloy micron-sized fibers includes the following steps:

[0019] First, Fe, Mn, Cr, Ni, and Mo elemental blocks (purity > 99%) were weighed according to an atomic ratio of 40:19:20:20:1 and smelted under argon protection to obtain FeMn. x CrNi-based high-entropy alloy melt; then, FeMn x CrNi-based high-entropy alloy melt is sprayed onto a high-speed rotating copper roller for rapid cooling at a rate of 10. 5 ~10 6 K / s, to obtain FeMn x CrNi-based high-entropy alloy thin strips; finally, FeMnx CrNi-based high-entropy alloy strips were mechanically cut into microwires with a width of 60µm.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The FeMn provided by this invention x CrNi-based high-entropy alloys (x=0.1, 0.15, 0.2 or 0.25) micron-sized powders have body-centered cubic (FCC) and face-centered cubic (BCC) crystal structures, exhibiting a lamellar appearance. Compared to Fe and Mn elemental powders, they have a higher degradation rate, reaching 97.6%, under the same experimental conditions.

[0022] 2. The Fe provided by this invention 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy micron-sized fibers, after multiple recycling processes, show little change in degradation efficiency, greatly expanding their application range.

[0023] In summary, the FeMn provided by this invention x The active zero-valent metal elements in CrNi-based high-entropy alloy micron-sized powders and / or fibers destroy the "-N=N-" groups in organic synthetic dyes through redox reactions, resulting in a degradation efficiency that is more than 10 times higher than that of commonly used commercial iron powders. Attached Figure Description

[0024] Figure 1 It is FeMn in Example 1 0.25 UV degradation diagram of CrNi powder in wastewater containing azo dye DB6.

[0025] Figure 2 Fe in Example 2 40 Mn 19 Cr 20 Ni 20 UV degradation diagram of wastewater containing azo dye DB6 by Mo1 microfilaments;

[0026] Figure 3 This is a UV degradation diagram of the wastewater containing Fe powder degrading the azo dye DB6 in Comparative Example 1;

[0027] Figure 4 This is a UV degradation diagram of wastewater containing Mn powder degrading azo dye DB6 in Comparative Example 2;

[0028] Figure 5 The FeMn in Example 1, Comparative Example 1, and Comparative Example 2 0.25 Comparison of degradation rates of azo dye DB6 wastewater by CrNi powder, Fe powder, and Mn powder. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Example 1

[0030] FeMn x The degradation of azo dye wastewater by micron-sized CrNi-based high-entropy alloy powder includes the following steps:

[0031] S1. Preparation of FeMn 0.25 Micron-sized CrNi high-entropy alloy powder: First, micron-sized Fe, Mn, Cr, and Ni elemental powders (purity > 99%) were weighed according to an atomic ratio of 1:0.25:1:1 and mixed and ground evenly in an agate mortar. Then, stainless steel grinding balls and the mixed metal powder were weighed according to a ball-to-powder ratio of 15:1 and placed in a stainless steel ball mill jar. The mixture was ball-milled using a high-energy planetary ball mill under argon protection at a speed of 300 r / min for 60 h, with anhydrous ethanol added as the grinding medium during the milling process. Finally, the high-entropy alloy powder was removed after milling and dried in a vacuum drying oven to obtain FeMn. 0.25 CrNi high-entropy alloy micron-sized powder;

[0032] S2, FeMn 0.25 Pretreatment of CrNi high-entropy alloy micron-sized powder: Weigh FeMn 0.25 0.3g of CrNi high-entropy alloy micron-sized powder was added to alcohol and ultrasonically cleaned for 15 minutes before use.

[0033] S3, using FeMn 0.25 Degradation of azo dye wastewater using CrNi high-entropy alloy micron-sized powder: Before degradation, 100 mL of a 50 mg / L DB6 solution was first added to a 250 mL beaker to simulate azo dye wastewater; then, the FeMn pretreated in step S2 was added... 0.25 CrNi-based high-entropy alloy micron-sized powder was added to azo dye wastewater at a degradation temperature of 25 ℃ and a pH of 3-7. Mechanical stirring was then performed at a speed of 200-600 r / min for 60 min. A stopwatch was used to time the degradation process, and 5 mL of the reaction solution was taken at appropriate intervals (5 min, 10 min, 15 min, 20 min, 30 min, 40 min, and 60 min) for subsequent UV testing.

[0034] S4. After the azo dye wastewater is completely degraded, FeMn 0.25 CrNi high-entropy alloy micron-sized powder is recycled and reused.

[0035] Figure 1This is FeMn in Example 1 0.25 The UV-Vis spectrum of wastewater from the degradation of DB6 azo dye by CrNi high-entropy alloy powder was obtained. The FeMn content can be calculated from this spectrum. 0.25 The CrNi high-entropy alloy powder basically completed the degradation of DB6 azo dye wastewater within 30 minutes, with a degradation rate of 96.2%. Example 2

[0036] FeMn x The degradation of azo dye wastewater by CrNi-based high-entropy alloy micron-sized fibers includes the following steps:

[0037] S1, Preparation of Fe 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy micron-sized fibers: First, Fe, Mn, Cr, Ni, and Mo elemental blocks (purity > 99%) were weighed according to an atomic ratio of 40:19:20:20:1, and then melted under argon protection to obtain Fe 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy melt; then, Fe 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy melt is sprayed onto a high-speed rotating copper roller for rapid cooling at a rate of 10. 5 ~10 6 K / s, to obtain Fe 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy thin strip; finally, Fe 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy strips are mechanically cut into microfilaments with a width of 60µm;

[0038] S2, Fe 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy micron-sized fiber pretreatment: Weigh Fe 40 Mn 19 Cr 20 Ni 20 0.3g of Mo1 high-entropy alloy micron-sized fibers were added to alcohol and ultrasonically cleaned for 15 minutes before use.

[0039] S3, using Fe 40 Mn19 Cr 20 Ni 20 Mo1 high-entropy alloy micron-sized fibers degrade azo dye wastewater: Before degradation, 100 mL of a 25 mg / L DB6 solution was first added to a 250 mL beaker to simulate azo dye wastewater. A 10 mmol / L H2O2 solution was then added to the azo dye wastewater as an oxidant for reaction. Then, the Fe pretreated in step S2 was... 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy micron-sized fibers were added to azo dye wastewater at a degradation temperature of 25 ℃ and a pH of 3. Mechanical stirring was then performed at a speed of 200-600 r / min for 60 min. A stopwatch was used to time the degradation process, and 5 mL of the reaction solution was taken at appropriate intervals (5 min, 10 min, 15 min, 20 min, 30 min, 40 min, and 60 min) for subsequent UV testing.

[0040] S4. After the azo dye wastewater is completely degraded, Fe... 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy micron-sized fibers are recycled and reused.

[0041] Figure 2 In this embodiment 2, Fe 40 Mn 19 Cr 20 Ni 20 The UV-Vis spectrum of Mo1 high-entropy alloy fiber degrading DB6 azo dye wastewater was obtained. Calculations can be performed to obtain the Fe... 40 Mn 19 Cr 20 Ni 20 Mo1 high-entropy alloy fiber filaments basically completed the degradation of DB6 azo dye wastewater within 60 minutes, with a degradation rate of 70.0%. Comparative Example 1

[0042] Comparative Example 1 provides a method for degrading azo dye wastewater using Fe powder, comprising the following steps:

[0043] Step 1: Pretreatment: Pour the weighed Fe powder into alcohol and sonicate for 15 minutes before use;

[0044] Step 2: Degradation: Pour 100 mL of 50 mg / L DB6 solution into a 250 mL beaker, then add 0.3 g of pretreated Fe powder to the DB6 solution to react. At the same time, turn on the mechanical stirrer to stir. All experiments were carried out at room temperature (25℃) and a stopwatch was started. After that, the reaction solution was taken at appropriate time intervals, and 5 mL of the solution was taken at 5 min, 10 min, 15 min, 20 min, 30 min, 40 min and 60 min respectively for subsequent ultraviolet testing.

[0045] Figure 3 This is a UV-Vis spectrophotometer degradation diagram of the azo dye (DB6) by Fe powder in Comparative Example 1. Calculations show that the powder did not react much within 60 minutes, and the degradation rate was 9.1%. Comparative Example 2

[0046] Comparative Example 2 provides a method for degrading azo dye wastewater using Mn powder, including the following steps:

[0047] Step 1: Pretreatment: Pour the weighed Mn powder into alcohol and sonicate for 15 minutes before use;

[0048] Step 2: Degradation: The steps are the same as those in Comparative Example 1, and will not be repeated here.

[0049] Figure 4 The image shows the degradation curve of the Mn powder prepared in Comparative Example 2 for the degradation of azo dye (DB6) by a UV-Vis spectrophotometer. Calculations show that the degradation rate of the powder reaches 65.4% in 30 min and 86.2% in 60 min.

[0050] like Figure 5 As shown, the FeMn provided in Example 1, Comparative Example 1, and Comparative Example 2 0.25 A comparison of the degradation rates of DB6 azo dye wastewater by CrNi high-entropy alloy powder, Fe powder, and Mn powder shows that the FeMn powder provided in this invention has the highest degradation rate. x CrNi-based high-entropy alloy micron-sized powders and / or fibers exhibit higher degradation rates under the same experimental conditions.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. FeMn x The application of CrNi-based high-entropy alloys in the degradation of azo dye wastewater is characterized by, FeMn used for the degradation of azo dye wastewater x CrNi-based high-entropy alloys are micron-sized powders and / or fibers, and FeMn... x CrNi-based high-entropy alloy micron-sized powders and / or FeMn x The concentration of CrNi-based high-entropy alloy micron-sized fibers in azo dye wastewater is greater than 3 g / L; The FeMn x The atomic ratio of Fe, Mn, Cr, and Ni in the micron-sized CrNi-based high-entropy alloy powder is 1:(0.1, 0.15, 0.2, 0.25):1:1; the FeMn... x The atomic ratio of Fe, Mn, Cr, Ni, and Mo in the micron-sized fibers of CrNi-based high-entropy alloys is 40:19:20:20:

1. The FeMn x The preparation method of CrNi-based high-entropy alloy micron-sized powder includes the following steps: First, micron-sized Fe, Mn, Cr, and Ni elemental powders were weighed out according to an atomic ratio of 1:(0.1, 0.15, 0.2, or 0.25):1:1, and mixed and ground evenly in an agate mortar. Then, stainless steel grinding balls and the mixed metal powders were weighed out according to a ball-to-powder ratio of 15:1, placed in a stainless steel ball mill jar, and ball-milled using a high-energy planetary ball mill under argon protection at a speed of 300 r / min for 60 h. Anhydrous ethanol was added as the grinding medium during the ball milling process. Finally, the high-entropy alloy powder was removed after ball milling and dried in a vacuum drying oven to obtain FeMn for degrading azo dye wastewater. x CrNi-based high-entropy alloy micron-sized powder; The FeMn x The preparation method of CrNi-based high-entropy alloy micron-sized fibers includes the following steps: First, Fe, Mn, Cr, Ni, and Mo elemental blocks were weighed according to an atomic ratio of 40:19:20:20:1, and then smelted under argon protection to obtain FeMn. x CrNi-based high-entropy alloy melt; then, FeMn x CrNi-based high-entropy alloy melt is sprayed onto a high-speed rotating copper roller for rapid cooling at a rate of 10. 5 ~10 6 K / s, to obtain FeMn x CrNi-based high-entropy alloy thin strips; finally, FeMn x CrNi-based high-entropy alloy strips were mechanically cut into microwires with a width of 60µm.

2. The application according to claim 1, characterized in that: The organic dye with azo bonds in the azo dye wastewater is Direct Blue 6 dye.

3. The application according to claim 1 or 2, characterized in that: The concentration of the azo dye wastewater to be degraded is 20-100 mg / L, the pH value of the azo dye wastewater is 3-7, and the degradation temperature is room temperature.

4. The application according to claim 1, characterized in that: FeMn x CrNi-based high-entropy alloy micron-sized powders and / or FeMn x The degradation of azo dye wastewater by CrNi-based high-entropy alloy micron-sized fibers includes the following steps: S1, FeMn x CrNi-based high-entropy alloy micron-sized powders and / or FeMn x CrNi-based high-entropy alloy micron-sized fibers were added to azo dye wastewater and then mechanically stirred at a speed of 200 r / min-600 r / min for 60 min. After the degradation of S2 and azo dye wastewater is complete, FeMn x CrNi-based high-entropy alloy micron-sized powders and / or FeMn x Micron-sized fibers of CrNi-based high-entropy alloys are recycled and reused.

5. The application according to claim 4, characterized in that: In step S1, before degradation, a 10 mmol / L H2O2 solution is added to the azo dye wastewater as an oxidant to carry out the reaction.

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