A Fenton oxidation reaction promoter and a method for promoting the Fenton oxidation reaction

Abstract

This invention provides a Fenton oxidation reaction promoter and a method for promoting the Fenton oxidation reaction. The promoter, by weight, comprises the following components in parts: 10-50 parts of a metal salt, 5-35 parts of a reducing agent, and 0-20 parts of an auxiliary agent. The amount of metal in the metal salt is not less than the amount of reducing agent, and the metal salt is selected from at least one of zinc or copper salts. The reducing agent is selected from at least one of sodium sulfide, sodium hydrosulfide, hydrogen sulfide, potassium sulfide, and potassium hydrosulfide. The auxiliary agent is selected from at least one of xanthic acid derivatives and dithiocarbamate derivatives. The Fenton oxidation reaction promoter is dissolved or suspended in water and added to the Fenton oxidation reaction process. It can promote the reduction rate of ferric iron, improve the Fenton oxidation effect, reduce the amount of iron added in the Fenton reaction, and thus reduce the yield of iron sludge. This promoter has the characteristics of low dosage, good effect, and simple and convenient use.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and more specifically, to a Fenton oxidation reaction promoter and its application. Background Technology

[0002] With the increasing severity of water pollution, people are paying more and more attention to wastewater. Currently, there are still some problems in the harmless treatment of wastewater, especially for wastewater that is difficult to degrade. Advanced oxidation technologies are generally used in such cases. Fenton oxidation technology is one such advanced oxidation technology, and it has developed rapidly due to its simple operation and strong adaptability. Fenton oxidation is an oxidation technology that uses hydrogen peroxide to generate hydroxyl radicals under the action of ferrous iron, and then uses these hydroxyl radicals to oxidize and degrade organic matter. Ferrous iron reacts with hydrogen peroxide to generate hydroxyl radicals, and ferrous iron is rapidly converted to ferric iron. The reaction rate constant K = 63~76 M. −1 s −1 The rate constant K for the reduction of ferric iron to ferrous iron by hydrogen peroxide is 0.001~0.01 M. −1 s −1 Therefore, the consumption rate of ferrous iron (Fe2+) is far greater than its generation rate. Thus, the reduction of ferric iron (Fe3+) to ferrous iron is the rate-limiting step in the Fenton reaction, affecting its oxidation efficiency. Consequently, traditional Fenton oxidation requires the addition of large amounts of ferrous iron, ultimately producing large quantities of iron sludge and causing secondary pollution. Currently, most methods use iron filings or zero-valent iron (Fe2+) for the reduction of ferric iron, such as patents CN104591426B and CN105923860B. Although the reduction effect of iron filings reduces the amount of iron added, iron dissolves from the filings, resulting in a small reduction in the iron content of the solution. Therefore, iron filings still need to be added over long-term operation. If the reaction rate of reducing ferric iron to ferrous iron can be increased, the amount of ferrous iron added and the production of iron sludge can be reduced, which will further promote the development of Fenton oxidation technology. Summary of the Invention

[0003] To address the above problems, this invention proposes a Fenton oxidation reaction promoter that can accelerate the reduction rate of ferric iron, improve the Fenton oxidation effect, reduce the amount of iron added in the Fenton reaction, and thus reduce the yield of iron sludge. This promoter features low dosage, high effectiveness, and simple and convenient use.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] The technical objective of the first aspect of this invention is to provide a Fenton oxidation reaction promoter, comprising, by weight, the following components in parts by weight:

[0006] 10-50 parts of metal salt

[0007] 5-35 parts reducing agent

[0008] 0-20 parts of auxiliary agent

[0009] Wherein, the amount of metal in the metal salt is not less than the amount of reducing agent, and the metal salt is selected from at least one of zinc salt or copper salt; the reducing agent is selected from at least one of sodium sulfide, sodium hydrosulfide, hydrogen sulfide, potassium sulfide and potassium hydrosulfide; and the auxiliary agent is selected from at least one of xanthic acid and dithiocarbamate derivatives.

[0010] Furthermore, the zinc or copper salt is selected from at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc hydroxide, zinc carbonate, zinc sulfide, copper sulfate, copper hydroxide, copper chloride, copper carbonate, copper nitrate, copper sulfide, and copper oxide. Preferably, it is selected from at least one of zinc sulfate, zinc sulfide, copper sulfate, and copper sulfide.

[0011] Furthermore, preferably, the Fenton oxidation reaction promoter comprises, by weight, the following components in parts by weight:

[0012] 20-40 parts of metal salt

[0013] 10-20 parts of reducing agent

[0014] 5-10 parts of auxiliary agent

[0015] Furthermore, the reducing agent is preferably at least one of sodium sulfide and sodium hydrosulfide; the auxiliary agent is preferably at least one of ethyl xanthic acid, methyl ethyl xanthate and sodium dimethyl dithiocarbamate.

[0016] Furthermore, the Fenton oxidation reaction promoter also includes water, which dissolves or suspends the components. Water is added at a solid mass percentage of 10-50%, preferably 20-40%.

[0017] Furthermore, the Fenton oxidation reaction promoter, after being dissolved or suspended in water, is further adjusted to a pH of 5-9, preferably 6-8, using a pH adjuster. The pH adjuster is an acid or a base, specifically sulfuric acid, sodium hydroxide, or potassium hydroxide.

[0018] The second aspect of the present invention aims to provide a method for promoting the Fenton oxidation reaction, which involves dissolving or suspending the Fenton oxidation reaction promoter in water and adding it to the Fenton oxidation reaction process.

[0019] Furthermore, the process of dissolving or suspending the Fenton oxidation reaction promoter in water involves adding water at a solid mass percentage of 10-50%, preferably 20-40%, and adjusting the pH to 5-9, preferably 6-8.

[0020] Furthermore, the dosage of the Fenton oxidation reaction promoter, based on the liquid weight of the formed solution or suspension, is 0.5 to 3 times the COD content in the water, preferably 1 to 2 times.

[0021] Furthermore, the pH adjustment is performed using sulfuric acid, sodium hydroxide, or potassium hydroxide.

[0022] Furthermore, the Fenton oxidation reaction promoter is added at the end of the Fenton oxidation reactor or to the reaction reflux liquid.

[0023] Implementing the technical solution of this invention will have the following advantages:

[0024] (1) The Fenton oxidation reaction promoter of the present invention, when applied to the Fenton oxidation process, can promote the reduction rate of ferric iron, improve the Fenton oxidation effect, and reduce the Fe content in the Fenton reaction. 2+ The amount of iron sludge added will be reduced, thereby reducing the production of iron sludge.

[0025] (2) The Fenton oxidation reaction promoter of the present invention consumes a small amount of zinc or copper, but overall promotes the reduction of ferric iron, with most of the zinc or copper acting as a catalyst.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0027] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0028] Solutions or suspensions of the Fenton oxidation reaction promoter of the present invention were prepared in Examples 1-6:

[0029] Example 1

[0030] To prepare a suspension of 10 kg of Fenton oxidation reaction accelerator: 2 kg zinc sulfate, 0.8 kg sodium sulfide, and the remainder water. The preparation method is as follows: Add the zinc sulfate solution to the sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0031] Example 2

[0032] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 2 kg zinc sulfate, 0.8 kg sodium sulfide, 0.1 kg sodium dimethyl dithiocarbamate, and the remainder water. The preparation method is as follows: Dissolve zinc sulfate and sodium dimethyl dithiocarbamate in water, then add sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0033] Example 3

[0034] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 2 kg zinc sulfate, 1 kg sodium sulfide, 0.1 kg ethyl xanthic acid, and the remainder water. The preparation method is as follows: Dissolve zinc sulfate and ethyl xanthic acid in water, then add sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0035] Example 4

[0036] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 2 kg zinc sulfate, 1 kg sodium sulfide, 0.1 kg methyl ethyl xanthate, and the remainder water. The preparation method is as follows: Dissolve zinc sulfate and methyl ethyl xanthate in water, then add sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0037] Example 5

[0038] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 2 kg copper sulfate, 1 kg sodium sulfide, 0.1 kg sodium dimethyl dithiocarbamate, and the remainder water. The preparation method is as follows: Dissolve copper sulfate and sodium dimethyl dithiocarbamate in water, then add sodium sulfide solution and adjust the pH to approximately 7 to obtain an emulsion. Stir well before use.

[0039] Example 6

[0040] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 2 kg zinc chloride, 1 kg sodium sulfide, 0.1 kg sodium dimethyl dithiocarbamate, and the remainder water. The preparation method is as follows: Dissolve zinc sulfate and sodium dimethyl dithiocarbamate in water, then add the sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0041] Example 7

[0042] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 3 kg zinc chloride, 1 kg sodium sulfide, 0.1 kg sodium dimethyl dithiocarbamate, and the remainder water. The preparation method is as follows: Dissolve zinc sulfate and sodium dimethyl dithiocarbamate in water, then add the sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0043] Example 8

[0044] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 4 kg zinc chloride, 1 kg sodium sulfide, 0.1 kg sodium dimethyl dithiocarbamate, and the remainder water. The preparation method is as follows: Dissolve zinc sulfate and sodium dimethyl dithiocarbamate in water, then add the sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0045] Example 9

[0046] To prepare a suspension of 10 kg of Fenton oxidation accelerator: 4 kg zinc chloride, 2 kg sodium sulfide, 0.1 kg sodium dimethyl dithiocarbamate, and the remainder water. The preparation method is as follows: Dissolve zinc sulfate and sodium dimethyl dithiocarbamate in water, then add the sodium sulfide solution and adjust the pH to approximately 7 to obtain a milky white turbid solution. Stir well before use.

[0047] Example 10

[0048] The Fenton oxidation reaction promoter prepared in the above examples was used in the Fenton oxidation reaction:

[0049] Wastewater containing Acid Red 3R (COD content of 200 mg / L) was subjected to continuous Fenton oxidation treatment with ferrous iron dosage of 100 mg / L or 30 mg / L. The Fenton oxidation accelerator suspension from the examples was added to the Fenton reaction reflux liquid as a blank control group without any accelerator. The experimental results are shown in Table 1.

[0050] Table 1.

[0051]

[0052] As shown in the table, the COD content of the effluent after Fenton oxidation was significantly reduced, and the COD removal rate was improved after using the Fenton oxidation accelerator. While ensuring good COD removal performance, the amount of iron added can be reduced. Therefore, this Fenton oxidation accelerator can improve the Fenton oxidation effect and reduce the amount of iron added in the Fenton reaction.

Claims

1. A method for promoting Fenton oxidation reaction, characterized in that, The Fenton oxidation reaction accelerator is dissolved or suspended in water and added to the Fenton oxidation reaction process; The Fenton oxidation reaction accelerator, by weight, comprises the following components in parts by weight: 10-50 parts of metal salt 5-35 parts reducing agent 1 part of auxiliary agent The amount of metal in the metal salt is not less than the amount of reducing agent, and the metal salt is selected from at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc carbonate, zinc sulfide, copper sulfate, copper chloride, copper carbonate, copper nitrate, and copper sulfide; the reducing agent is at least one of sodium sulfide and sodium hydrosulfide; and the auxiliary agent is selected from at least one of ethyl xanthic acid, methyl ethyl xanthate, and sodium dimethyl dithiocarbamate.

2. The method according to claim 1, characterized in that, The process of dissolving or suspending the Fenton oxidation reaction promoter in water involves adding water at a solid mass percentage of 10-50% and adjusting the pH to 5-9.

3. The method according to claim 1, characterized in that, The dosage of the Fenton oxidation reaction promoter, based on the liquid weight of the formed solution or suspension, is 0.5-20% of the COD content in the water.

4. The method according to claim 2, characterized in that, The pH is adjusted using sulfuric acid, sodium hydroxide, or potassium hydroxide.

5. The method according to claim 1, characterized in that, The Fenton oxidation reaction promoter is added at the end of the Fenton oxidation reactor or to the reaction reflux liquid.

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