A method for enhancing the removal of organic pollutants from water using ferrates

Abstract

This invention discloses a method for enhancing the removal of organic pollutants from water using ferrates, relating to the field of wastewater treatment. The reagents include 2,2-bipyridine and ferrate. 2,2-bipyridine and ferrate are added sequentially to the water sample to be treated, and the mixture is stirred to oxidize the ferrate and remove organic pollutants. The ferrate used in this application does not produce toxic or harmful substances and does not cause secondary pollution to the environment. When ferrate is added to water, Fe(VI) is released, which self-decomposes to generate unstable Fe(IV), which is then complexed by 2,2-bipyridine, reducing the amount of Fe(IV) further forming Fe(II). Simultaneously, 2,2-bipyridine can complex Fe(II), further reducing the consumption of Fe(VI) by Fe(II), thus increasing the concentration of Fe(IV) and Fe(VI) available for pollutant degradation and significantly improving the pollutant degradation efficiency.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and more particularly to a method for enhancing the removal of organic pollutants from water using ferrates. Background Technology

[0002] Ferrate (Fe(VI)) is a highly efficient water treatment agent that integrates oxidation, flocculation, disinfection, and deodorization functions, and has great application prospects in the water treatment field. Fe(VI) has a strong oxidizing ability and is the strongest oxidant in water treatment. In the redox process, FeO4... 2- Reduced to Fe 3+ Flocculent colloids such as Fe(OH)3 can further remove organic and inorganic pollutants from water, and the reaction process does not produce toxic and harmful chlorine pollutants such as chloroform, which would cause secondary pollution.

[0003] Studies have shown that Fe(VI) and Fe(IV) are important active substances for degrading micropollutants. However, Fe(VI) is inherently unstable and readily decomposes to produce Fe(IV), which in turn is also unstable and further decomposes into Fe(II). Notably, the generated Fe(II) further consumes Fe(VI), reducing the concentration of available Fe(VI) in the water and consequently lowering the overall oxidation level. Therefore, inhibiting the self-decomposition of Fe(IV) and reducing the consumption of Fe(VI) by Fe(II) are crucial issues in the current application of Fe(VI) oxidation for pollutant removal. Summary of the Invention

[0004] This invention provides a method for enhancing the removal of organic pollutants from water using ferrates, in order to solve the technical problem of low degradation efficiency of pollutants in water samples treated with ferrates.

[0005] To address the aforementioned technical problems, one objective of this invention is to provide a reagent for enhancing the removal of organic pollutants from water using ferrates, comprising 2,2-bipyridine and ferrates.

[0006] By adopting the above scheme, 2,2-bipyridine (BPY) is used to complex Fe(IV) and Fe(II). On the one hand, 2,2-bipyridine can complex Fe(IV) to make it more stable. On the other hand, 2,2-bipyridine can complex Fe(II) to inhibit its consumption of Fe(VI), thereby increasing the concentration of Fe(IV) and Fe(VI) available in the water, and thus efficiently degrading pollutants.

[0007] As a preferred embodiment, the ferrate is sodium ferrate and / or potassium ferrate.

[0008] To address the aforementioned technical problems, a second objective of this invention is to provide a method for enhancing the removal of organic pollutants from water using ferrates, comprising the following steps: sequentially adding 2,2-bipyridine and ferrate to the water sample to be treated, stirring the reaction to oxidize the ferrates and remove the organic pollutants, and adjusting the pH of the buffer solution to 6-10 before the reaction.

[0009] As a preferred embodiment, the Fe content after the ferrate is added is 50 μmol / L.

[0010] As a preferred embodiment, the dosage of 2,2-bipyridine is 0.1-0.5 mmol / L.

[0011] As a preferred embodiment, the dosage of 2,2-bipyridine is 0.5-5 mmol / L.

[0012] As a preferred embodiment, the molar ratio of Fe content in the 2,2-bipyridine and ferrate is 10:1.

[0013] As a preferred approach, the pH of the buffer solution is adjusted using sodium hydroxide or perchloric acid before the reaction. By employing the above method, during the treatment of pollutants in the water sample, a pH outside the range of 6-10 will cause ferric sulfate (Fe(VI)) to decompose rapidly under excessively acidic conditions, while under excessively alkaline conditions, the oxidizing capacity of ferric sulfate (Fe(VI)) is too low to achieve degradation, resulting in reduced pollutant treatment efficiency.

[0014] As a preferred option, the stirring speed during the stirring reaction is 300-1000 r / min.

[0015] As a preferred option, the stirring reaction time is 3-10 min.

[0016] To address the aforementioned technical problems, a third objective of this invention is to provide an application of a method for enhancing the removal of organic pollutants from water using ferrates in the fields of removing organic pollutants, sterilization, deodorization, or algae removal.

[0017] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0018] The ferrate in this application is a strong oxidant that does not produce toxic or harmful substances and does not cause secondary pollution to the environment. When ferrate is added to water, it releases Fe(VI), which can self-decompose to generate unstable Fe(IV). Fe(IV) becomes more stable after being complexed by the added 2,2-bipyridine, reducing the amount of Fe(IV) that further generates Fe(II). At the same time, 2,2-bipyridine can complex Fe(II), thereby reducing the consumption of Fe(VI) by Fe(II). This increases the concentration of Fe(IV) and Fe(VI) available for degrading pollutants, significantly improving the degradation efficiency of pollutants. Attached Figure Description

[0019] Figure 1 : These are the statistical results of the sulfamethoxazole degradation efficiency of a method for removing organic pollutants from water using enhanced ferrates, as described in Examples 1-4 and Comparative Example 1 of this invention.

[0020] Figure 2 : These are the statistical results of the sulfamethoxazole degradation efficiency of a method for removing organic pollutants from water using enhanced ferrates in Examples 4-7 and Comparative Example 1 of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1

[0023] A method for enhancing the removal of organic pollutants from water using ferrates includes the following steps:

[0024] 2,2-Bipyridine was added at 0.1 mmol / L to a buffer solution containing 5 μmol / L sulfamethoxazole, followed by the addition of ferrate at 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0025] Example 2

[0026] A method for enhancing the removal of organic pollutants from water using ferrates includes the following steps:

[0027] 2,2-Bipyridine was added at 0.2 mmol / L to a buffer solution containing 5 μmol / L sulfamethoxazole, followed by the addition of ferrate at 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0028] Example 3

[0029] A method for enhancing the removal of organic pollutants from water using ferrates includes the following steps:

[0030] 2,2-Bipyridine was added at 0.3 mmol / L to a buffer solution containing 5 μmol / L sulfamethoxazole, followed by the addition of ferrate at 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0031] Example 4

[0032] A method for enhancing the removal of organic pollutants from water using ferrates includes the following steps:

[0033] 2,2-Bipyridine was added at 0.5 mmol / L to a buffer solution containing 5 μmol / L sulfamethoxazole, followed by the addition of ferrate at 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0034] Example 5

[0035] A method for enhancing the removal of organic pollutants from water using ferrates includes the following steps:

[0036] 2,2-Bipyridine was added at 1 mmol / L to a buffer solution containing 5 μmol / L sulfamethoxazole, followed by the addition of ferrate at 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0037] Example 6

[0038] A method for enhancing the removal of organic pollutants from water using ferrates includes the following steps:

[0039] 2,2-Bipyridine was added at 2 mmol / L to a buffer solution containing 5 μmol / L sulfamethoxazole, followed by the addition of ferrate at 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0040] Example 7

[0041] A method for enhancing the removal of organic pollutants from water using ferrates includes the following steps:

[0042] 2,2-Bipyridine was added at 5 mmol / L to a buffer solution containing 5 μmol / L sulfamethoxazole, followed by the addition of ferrate at 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0043] Comparative Example 1

[0044] A method for removing contaminants from water using ferrates includes the following steps:

[0045] Ferrate was added to a buffer solution containing 5 μmol / L sulfamethoxazole at a concentration of 50 μmol / L. In this embodiment, the amount of ferrate added is calculated as Fe. The mixture was stirred for 5 min to complete the oxidation and removal of organic pollutants by ferrate. The ferrate was a potassium ferrate solution. Before the reaction, the pH of the buffer solution was adjusted to 8 using sodium hydroxide or perchloric acid. The reaction stirring speed was 600 r / min.

[0046] Performance testing experiment

[0047] Sulfamethoxazole degradation efficiency (%): Methanol and a prepared 0.1% acetic acid were used as the mobile phase for liquid chromatography detection. High-performance liquid chromatography (High Performance Liquid Chromatography (Waters)) was used to detect the peak area changes of sulfamethoxazole over the corresponding time period for analysis. Based on the measured data, Origin software was used to plot the data and compare the concentration trends of the pollutant over time in potassium ferrate alone and in the 2,2-bipyridine / potassium ferrate system. This analysis aimed to assess the effect of 2,2-bipyridine on promoting the degradation of pollutants by potassium ferrate. The degradation efficiencies are shown in Table 1 below. Figure 1-2 As shown, Figure 1The chart shows the degradation efficiency statistics for Examples 1-4 and Comparative Example 1. Figure 2 The chart shows the degradation efficiency statistics for Examples 4-7 and Comparative Example 1.

[0048] Table 1 - Degradation efficiency results of sulfamethoxazole in the examples and comparative examples of this application.

[0049]

[0050] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A reagent for enhancing the removal of organic pollutants from water using ferrates, characterized in that, Including 2,2-bipyridine and ferrate.

2. The reagent for enhancing the removal of organic pollutants from water using ferrate as described in claim 1, characterized in that, The ferrate is sodium ferrate and / or potassium ferrate.

3. A method for enhancing the removal of organic pollutants from water using ferrates, characterized in that, The reagent for removing organic pollutants from water using enhanced ferrate as described in claim 1 or 2 includes the following steps: adding 2,2-bipyridine and ferrate sequentially to the water sample to be treated, stirring the reaction to oxidize the ferrate and remove organic pollutants, and adjusting the pH of the buffer solution to 6-10 before the reaction.

4. The method for enhancing the removal of organic pollutants from water using ferrates as described in claim 3, characterized in that, The Fe content after the addition of the ferrate is 50 μmol / L.

5. The method for enhancing the removal of organic pollutants from water using ferrates as described in claim 3, characterized in that, The dosage of the 2,2-bipyridine is 0.1-0.5 mmol / L.

6. The method for enhancing the removal of organic pollutants from water using ferrates as described in claim 5, characterized in that, The dosage of 2,2-bipyridine is 0.5-5 mmol / L.

7. The method for enhancing the removal of organic pollutants from water using ferrates as described in claim 3, characterized in that, The molar ratio of Fe content in the 2,2-bipyridine and ferrate is 10:

1.

8. The method for enhancing the removal of organic pollutants from water using ferrates as described in claim 3, characterized in that, The pH of the buffer solution was adjusted with sodium hydroxide or perchloric acid before the reaction.

9. The method for enhancing the removal of organic pollutants from water using ferrates as described in claim 3, characterized in that, During the stirring reaction, the stirring speed is 300-1000 r / min, and the stirring reaction time is 3-10 min.

10. The application of a reagent for removing organic pollutants from water by enhanced ferrate as described in claim 1 or 2 in the fields of removing organic pollutants, sterilization, deodorization or algae removal.

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