Method for efficiently degrading organic fluorine-containing wastewater by catalyzing hydrogen peroxide through ferrous sulfide synergistic ferric sulfate binary system

Abstract

The invention discloses a method for efficiently degrading organic fluorine-containing wastewater by catalyzing hydrogen peroxide through a ferrous sulfide synergistic ferric sulfate binary system, belongs to the field of sewage treatment, is used for sewage treatment, and comprises the following steps: preparing a ferric sulfate solution and ferrous sulfide powder, adjusting the pH value of the organic fluorine-containing wastewater in a reactor to 3-4, adding ferrous sulfide, and stirring to obtain a ferric sulfate solution; adding ferrous sulfide into the reactor to enable the concentration of the ferrous sulfide to be not lower than 3.2 g / L, adding a ferric sulfate solution, stirring in a magnetic stirrer, primarily adding 77mM of hydrogen peroxide into the reactor after stirring is completed, adding 38.5 mM of hydrogen peroxide in batches at intervals in the reaction process, and continuously stirring until the reaction is complete; adding a sodium hydroxide solution into a sample sampled from the reactor until the reaction is ended, and measuring the removal amount of organic matters in the organic fluorine wastewater after centrifugal precipitation. According to the application, the organic fluorine-containing wastewater can be efficiently removed by utilizing cheap ferrous sulfide and ferric sulfate to synergistically catalyze hydrogen peroxide.

Description

Technical Field

[0001] This application belongs to the field of wastewater treatment, and more specifically, it relates to a method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide catalyzed by a binary system of ferrous sulfide and ferric sulfate. Background Technology

[0002] Organic fluorides are widely used in refrigerants, semiconductor manufacturing, energy storage temperature control, precision cleaning, and lubrication. However, the widespread use of organic fluorides has also led to the generation of organic fluoride-containing wastewater, especially wastewater containing perfluorinated and polyfluoroalkyl substances (PFAS). Organic fluoride-containing wastewater is characterized by its persistence, bioaccumulation, long-distance migration, difficulty in treatment, and significant hazards.

[0003] Existing technologies for treating organic fluoride-containing wastewater have significant limitations. Examples include activated carbon adsorption and membrane separation. While activated carbon adsorption is effective for long-chain organic fluorides, it essentially only transfers the pollutants rather than removes them, making subsequent treatment difficult. Membrane separation (including microfiltration / ultrafiltration, nanofiltration / reverse osmosis) uses pressure-driven separation and membrane pore size sieving or dissolution-diffusion principles to separate pollutants, but it also faces the challenge of treating the concentrated wastewater or retained residues after separation.

[0004] To address the challenges of treating organic fluoride-containing wastewater using existing technologies, advanced oxidation processes have emerged, such as the Fenton process and persulfate oxidation. These processes generate free radicals to break down organic matter, achieving degradation or mineralization. However, conventional advanced oxidation methods have limited efficiency in treating organic fluoride-containing wastewater; the Fenton process and persulfate oxidation, for example, can only remove 20%–40% of the pollutants.

[0005] Therefore, given the challenges of treating organic fluoride-containing wastewater, including high difficulty, high cost, and limited treatment efficiency, developing a new, more efficient, economical, and environmentally friendly treatment technology suitable for low-concentration and complex-quality organic fluoride-containing wastewater has become one of the technical problems that the industry needs to solve. Summary of the Invention

[0006] The purpose of this application is to provide a method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide catalyzing a binary system of ferrous sulfide and ferric sulfate, which can achieve the efficient removal of organic fluoride-containing wastewater by utilizing inexpensive ferrous sulfide and ferric sulfate to catalyze hydrogen peroxide.

[0007] To achieve the above objectives, this application employs the following technical solution:

[0008] The method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide catalyzed by a binary system of ferrous sulfide and ferric sulfate as described in this application includes the following steps:

[0009] (1) Prepare a 1M ferric sulfate solution for later use. Crush and grind ferrous sulfide into powder with a particle size of 90~100 mesh. Soak the ground ferrous sulfide powder in a 2mM sulfuric acid solution until the fresh surface of ferrous sulfide is exposed. After soaking, rinse with deionized water until there is no residual sulfuric acid solution on the surface and then set aside for use.

[0010] (2) Add organic fluoride wastewater to the reactor and slowly add 2M sulfuric acid solution until the pH value of the organic fluoride wastewater is measured to be 3~4 by a pH meter, then stop adding sulfuric acid solution;

[0011] (3) Add the ferrous sulfide powder with the fresh surface exposed after step (1) to the reactor in step (2), and ensure that the mass concentration of ferrous sulfide after addition is not less than 3.2 g / L. At the same time, add 1 ml of 1 M ferric sulfate solution to the reactor in step (2).

[0012] (4) Place the reactor from step (3) in a magnetic stirrer and set the rotation speed to 1800~2000 r / min and the stirring time to 10 min;

[0013] (5) Add 77mM hydrogen peroxide to the reactor at the end of step (4) for the first time, and add 38.5mM hydrogen peroxide at the 20 min, 45 min and 90 min of the reaction respectively. Set the speed of the magnetic stirrer to 1800~2000r / min and the stirring time to 120min.

[0014] (6) Take samples at time points of 0 min, 10 min, 20 min, 30 min, 45 min, 60 min, 90 min and 120 min after the start of the reaction in step (5). Take 5 mL of sample and add the 5 mL sample to a test tube containing 0.2 mL of 6M sodium hydroxide solution. Shake well to terminate the reaction.

[0015] (7) Centrifuge the sample from step (6) to terminate the reaction and measure the amount of organic matter removed from the organic fluorine wastewater after precipitation is complete.

[0016] Compared with the prior art, the beneficial effects of this application are:

[0017] This application employs a system of ferrous sulfide and ferric sulfate activated hydrogen peroxide to treat organic fluoride-containing wastewater. Experiments have demonstrated that this technology can significantly reduce COD in the wastewater, indicating that organic pollutants are effectively degraded or mineralized. It can also significantly reduce the formation of ferric hydroxide precipitate, effectively improve the utilization rate of hydrogen peroxide and the efficiency of pollutant degradation / mineralization. Furthermore, ferrous sulfide and ferric sulfate are relatively inexpensive and readily available, requiring less sophisticated equipment, simple to operate, and significantly reducing treatment costs. The removal rate of pollutants in organic fluoride-containing wastewater can reach over 70%. Attached Figure Description

[0018] Figure 1 This is a diagram illustrating the mechanism by which ferrous sulfide and ferric sulfate activate hydrogen peroxide to remove organic fluoride-containing wastewater in this application.

[0019] Figure 2 This is a chart showing the degradation and removal rate of organic pollutants in the organic fluoride-containing wastewater in Examples 1 to 4 of this application. Detailed Implementation

[0020] The technical solutions described in this application will be further described below with reference to the accompanying drawings and embodiments.

[0021] Example 1

[0022] A method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide through a binary system of ferrous sulfide and ferric sulfate, comprising the following steps:

[0023] (1) Prepare a 1M ferric sulfate solution for later use. Crush and grind ferrous sulfide into powder with a particle size of 90~100 mesh. Weigh 3.2g of the ground ferrous sulfide powder and soak it in a 2mM sulfuric acid solution until the fresh surface of ferrous sulfide is exposed. After soaking, rinse with deionized water until there is no residual sulfuric acid solution on the surface and then set aside for use.

[0024] (2) 50 mL of organic fluoride wastewater was taken from the production wastewater of a material company in Gansu. The COD concentration of the wastewater reached 8500~11000 mg / L and the pH of the organic fluoride wastewater was 6.5. The organic fluoride wastewater was added to the reactor and 2M sulfuric acid solution was added slowly until the pH of the organic fluoride wastewater was measured to be 3.5 by a pH meter and then the addition of sulfuric acid solution was stopped.

[0025] (3) Add the ferrous sulfide powder with the fresh surface exposed after step (1) to the reactor in step (2), and ensure that the mass concentration of ferrous sulfide after addition is not less than 3.2 g / L. At the same time, add 1 ml of 1 M ferric sulfate solution to the reactor in step (2).

[0026] (4) Place the reactor from step (3) in a magnetic stirrer and set the rotation speed to 1800~2000 r / min and the stirring time to 10 min;

[0027] (5) Add 77mM hydrogen peroxide to the reactor at the end of step (4) for the first time, and add 38.5mM hydrogen peroxide at the 20 min, 45 min and 90 min of the reaction respectively. Keep the speed of the magnetic stirrer at 1800~2000r / min and set the stirring time to 120min.

[0028] (6) Take samples at time points of 0 min, 10 min, 20 min, 30 min, 45 min, 60 min, 90 min and 120 min after the start of the reaction in step (5). Take 5 mL of sample and add the 5 mL sample to a test tube containing 0.2 mL of 6M sodium hydroxide solution. Shake well to terminate the reaction.

[0029] (7) Centrifuge the sample that terminated the reaction in step (6) and measure the removal rate of organic matter in the organic fluorine wastewater after precipitation is completed. The removal rate of organic matter in the organic fluorine wastewater is 78%.

[0030] Example 2

[0031] A method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide through a binary system of ferrous sulfide and ferric sulfate, comprising the following steps:

[0032] (1) Prepare a 1M ferric sulfate solution for later use. Crush and grind ferrous sulfide into powder with a particle size of 90~100 mesh. Weigh 3.6g of the ground ferrous sulfide powder and soak it in a 2mM sulfuric acid solution until the fresh surface of ferrous sulfide is exposed. After soaking, rinse with deionized water until there is no residual sulfuric acid solution on the surface and then set aside for use.

[0033] (2) 50 mL of organic fluoride wastewater was taken from the production wastewater of a material company in Gansu. The COD concentration of the wastewater reached 8500~11000 mg / L and the pH of the organic fluoride wastewater was 6.5. The organic fluoride wastewater was added to the reactor and 2M sulfuric acid solution was added slowly until the pH of the organic fluoride wastewater was measured to be 3.5 by a pH meter and then the addition of sulfuric acid solution was stopped.

[0034] (3) Add the ferrous sulfide powder with the fresh surface exposed after step (1) to the reactor in step (2), and ensure that the mass concentration of ferrous sulfide after addition is not less than 3.6 g / L. At the same time, add 1 ml of 1 M ferric sulfate solution to the reactor in step (2).

[0035] (4) Place the reactor from step (3) in a magnetic stirrer and set the rotation speed to 1800~2000 r / min and the stirring time to 10 min;

[0036] (5) Add 77mM hydrogen peroxide to the reactor at the end of step (4) for the first time, and add 38.5mM hydrogen peroxide at the 20 min, 45 min and 90 min of the reaction respectively. Keep the speed of the magnetic stirrer at 1800~2000r / min and set the stirring time to 120min.

[0037] (6) Take samples at time points of 0 min, 10 min, 20 min, 30 min, 45 min, 60 min, 90 min and 120 min after the start of the reaction in step (5). Take 5 mL of sample and add the 5 mL sample to a test tube containing 0.2 mL of 6M sodium hydroxide solution. Shake well to terminate the reaction.

[0038] (7) Centrifuge the sample that terminated the reaction in step (6) and measure the removal rate of organic matter in the organic fluorine wastewater after precipitation is completed. The removal rate of organic matter in the organic fluorine wastewater is 72%.

[0039] Example 3

[0040] A method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide through a binary system of ferrous sulfide and ferric sulfate, comprising the following steps:

[0041] (1) Prepare a 1M ferric sulfate solution for later use. Crush and grind ferrous sulfide into powder with a particle size of 90~100 mesh. Weigh 4.0g of the ground ferrous sulfide powder and soak it in a 2mM sulfuric acid solution until the fresh surface of ferrous sulfide is exposed. After soaking, rinse with deionized water until there is no residual sulfuric acid solution on the surface and weigh it for later use.

[0042] (2) 50 mL of organic fluoride wastewater was taken from the production wastewater of a material company in Gansu. The COD concentration of the wastewater reached 8500~11000 mg / L and the pH of the organic fluoride wastewater was 6.5. The organic fluoride wastewater was added to the reactor and 2M sulfuric acid solution was added slowly until the pH of the organic fluoride wastewater was measured to be 3.5 by a pH meter and then the addition of sulfuric acid solution was stopped.

[0043] (3) Add the ferrous sulfide powder with the fresh surface exposed after step (1) to the reactor in step (2), and ensure that the mass concentration of ferrous sulfide after addition is not less than 4.0 g / L. At the same time, add 1 ml of 1 M ferric sulfate solution to the reactor in step (2).

[0044] (4) Place the reactor from step (3) in a magnetic stirrer and set the rotation speed to 1800~2000 r / min and the stirring time to 10 min;

[0045] (5) Add 77mM hydrogen peroxide to the reactor at the end of step (4) for the first time, and add 38.5mM hydrogen peroxide at the 20 min, 45 min and 90 min of the reaction respectively. Keep the speed of the magnetic stirrer at 1800~2000r / min and set the stirring time to 120min.

[0046] (6) Take samples at time points of 0 min, 10 min, 20 min, 30 min, 45 min, 60 min, 90 min and 120 min after the start of the reaction in step (5). Take 5 mL of sample and add the 5 mL sample to a test tube containing 0.2 mL of 6M sodium hydroxide solution. Shake well to terminate the reaction.

[0047] (7) Centrifuge the sample that terminated the reaction in step (6) and measure the removal rate of organic matter in the organic fluorine wastewater after precipitation is completed. The removal rate of organic matter in the organic fluorine wastewater is 73%.

[0048] Example 4

[0049] A method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide through a binary system of ferrous sulfide and ferric sulfate, comprising the following steps:

[0050] (1) Prepare a 1M ferric sulfate solution for later use. Crush and grind ferrous sulfide into powder with a particle size of 90~100 mesh. Weigh 4.4g of the ground ferrous sulfide powder and soak it in a 2mM sulfuric acid solution until the fresh surface of ferrous sulfide is exposed. After soaking, rinse with deionized water until there is no residual sulfuric acid solution on the surface and weigh it for later use.

[0051] (2) 50 mL of organic fluoride wastewater was taken from the production wastewater of a material company in Gansu. The COD concentration of the wastewater reached 8500~11000 mg / L and the pH of the organic fluoride wastewater was 6.5. The organic fluoride wastewater was added to the reactor and 2M sulfuric acid solution was added slowly until the pH of the organic fluoride wastewater was measured to be 3.5 by a pH meter and then the addition of sulfuric acid solution was stopped.

[0052] (3) Add the ferrous sulfide powder with the fresh surface exposed after step (1) to the reactor in step (2), and ensure that the mass concentration of ferrous sulfide after addition is not less than 4.4 g / L. At the same time, add 1 ml of 1 M ferric sulfate solution to the reactor in step (2).

[0053] (4) Place the reactor from step (3) in a magnetic stirrer and set the rotation speed to 1800~2000 r / min and the stirring time to 10 min;

[0054] (5) Add 77mM hydrogen peroxide to the reactor at the end of step (4) for the first time, and add 38.5mM hydrogen peroxide at the 20 min, 45 min and 90 min of the reaction respectively. Keep the speed of the magnetic stirrer at 1800~2000r / min and set the stirring time to 120min.

[0055] (6) Take samples at time points of 0 min, 10 min, 20 min, 30 min, 45 min, 60 min, 90 min and 120 min after the start of the reaction in step (5). Take 5 mL of sample and add the 5 mL sample to a test tube containing 0.2 mL of 6M sodium hydroxide solution. Shake well to terminate the reaction.

[0056] (7) Centrifuge the sample that terminated the reaction in step (6) and measure the removal rate of organic matter in the organic fluorine wastewater after precipitation is completed. The removal rate of organic matter in the organic fluorine wastewater is 74%.

[0057] Ferrous sulfide (FeS) exists in nature as minerals such as pyrrhotite and troilite, participating in geological and sedimentary processes. It is widely used in industry and laboratories as a raw material, reagent, or functional material. Ferrous sulfide has significant advantages in heavy metal remediation; for example, it can efficiently reduce highly toxic Cr(VI) to Cr(III) and precipitate it; it can also directly precipitate Hg. 2+ Cd 2+ Pb 2+ As a poorly soluble sulfide, FeS synergistically fixes arsenic (As). In the ferrous sulfide-coupled ferric sulfate Fenton system, FeS plays an important role, continuously releasing Fe under acidic conditions. 2+ At the same time, it efficiently reduces Fe. 3+ To regenerate Fe 2+ .

[0058] See Figure 1 In this application, (1) iron sulfide undergoes an initial reaction with Fe2(SO4)3: S in FeS 2- It will be Fe 3+ (From ferric sulfate) oxidation, releasing Fe in the process. 2+ The reaction equation is as follows:

[0059]

[0060] Adding ferric sulfate at the beginning of the reaction accelerates its initiation, helping to reduce reaction time, and Fe... 3+The reaction with FeS can sustainably provide Fe 2+ To avoid Fe in the traditional Fenton reaction 2+ The problem of rapid depletion.

[0061] (2) Fenton Cycle

[0062] In the above reaction, the generated Fe 2+ It undergoes a classic Fenton reaction with the subsequently added H2O2:

[0063]

[0064] At the same time, Fe 3+ FeS can be reduced back to Fe 2+ This forms a cycle:

[0065]

[0066] (3) Free radical oxide pollution

[0067] Continuously generated and (Sulfate radicals) efficiently degrade organic matter:

[0068]

[0069] The core mechanism of this application lies in the continuous release of Fe from FeS. 2+ and strong reducing S 2- Synergistic effect greatly enhances Fe 3+ / Fe 2+ Cycle. Fe2(SO4)3 also plays an indispensable dual role in this process: providing initial Fe... 3+ To achieve rapid reaction initiation and shorten the induction period, and through the Fe it provides... 3+ Fe produced by the continuous reduction of FeS 2+ Collaborative construction of a two-way iron cycle (Fe 3+ / Fe 2+ This significantly improves catalytic efficiency and sustainability. It not only significantly increases reaction efficiency but also brings multiple advantages: it can drastically reduce the formation of ferric hydroxide precipitate (iron sludge), effectively improve H2O2 utilization, and enhance sludge degradation / mineralization efficiency.

[0070] Finally, although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for the efficient degradation of organic fluoride-containing wastewater by hydrogen peroxide catalyzed by a binary system of ferrous sulfide and ferric sulfate, characterized in that, The method includes the following steps: (1) Prepare a 1M ferric sulfate solution for later use. Crush and grind ferrous sulfide into powder with a particle size of 90~100 mesh. Soak the ground ferrous sulfide powder in a 2mM sulfuric acid solution until the fresh surface of ferrous sulfide is exposed. After soaking, rinse with deionized water until there is no residual sulfuric acid solution on the surface and then set aside for use. (2) Add organic fluoride wastewater to the reactor and slowly add 2M sulfuric acid solution until the pH value of the organic fluoride wastewater is measured to be 3~4 by a pH meter, then stop adding sulfuric acid solution; (3) Add the ferrous sulfide powder with the fresh surface exposed after step (1) to the reactor in step (2), and ensure that the mass concentration of ferrous sulfide after addition is not less than 3.2 g / L. At the same time, add 1 ml of 1 M ferric sulfate solution to the reactor in step (2). (4) Place the reactor from step (3) in a magnetic stirrer and set the rotation speed to 1800~2000 r / min and the stirring time to 10 min; (5) Add 77mM hydrogen peroxide to the reactor at the end of step (4) for the first time, and add 38.5mM hydrogen peroxide at the 20 min, 45 min and 90 min of the reaction respectively. Set the speed of the magnetic stirrer to 1800~2000r / min and the stirring time to 120min. (6) Take samples at time points of 0 min, 10 min, 20 min, 30 min, 45 min, 60 min, 90 min and 120 min after the start of the reaction in step (5). Take 5 mL of sample and add the 5 mL sample to a test tube containing 0.2 mL of 6M sodium hydroxide solution. Shake well to terminate the reaction. (7) Centrifuge the sample from step (6) to terminate the reaction and measure the amount of organic matter removed from the organic fluorine wastewater after precipitation is complete.

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