Hydrated electron solution for degrading pollutants and its use
By preparing an ionic liquid reverse micelle system with hydrated electrons, the problems of low degradation efficiency and high cost of recalcitrant pollutants in water were solved, and efficient degradation of perfluorinated compounds and bromate was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANGZHOU UNIV
- Filing Date
- 2024-12-18
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies are difficult to efficiently degrade recalcitrant organic pollutants such as perfluorinated compounds and inorganic pollutants such as bromate in water, and are also costly.
By preparing ionic liquid reverse micelle systems of [Bmim]PF6 and [C16mim]PF6 with PBS solution under ultrasonic conditions to form hydrated electrons, pollutants are degraded by utilizing the strong reducing properties of hydrated electrons.
It achieves high degradation rates of perfluorinated compounds and bromate, reaching over 75% and 91% respectively, and the preparation method is simple and low-cost.
Smart Images
Figure CN119660938B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a hydrated electron solution for degrading pollutants and its application, belonging to the field of pollutant degradation technology. Background Technology
[0002] In recent years, a new concept of advanced reduction technology has emerged in the water treatment field. This technology combines activation methods such as ultraviolet light with reducing agents such as sulfites to produce strongly reducing substances (such as hydrated electrons and hydrogen atoms). It can efficiently reduce and degrade recalcitrant organic pollutants such as chlorinated and fluorinated organic compounds, as well as inorganic pollutants such as perchlorate, bromate, and nitrate, showing broad application prospects in water treatment. When electrons are removed from or accepted by the constituent ions, the ionization of ionic liquids (ILs) typically produces free radicals, anions or neutral free radicals, hydrogen atoms, and hydrated electrons. Irradiation is the most common approach in advanced reduction technologies. In addition, chemical methods can also produce hydrated electrons, such as reactions between metals and strongly alkaline aqueous solutions, catalytic hydrogenation reactions of organic matter in alkaline solutions, and electrolytic reactions using sodium amalgam electrodes. Experimental reports indicate that 4-hydroxycoumarin in aqueous solution can produce hydrated electrons after exposure to sunlight. These hydrated electrons promote the reduction of nitrobenzene to 4-aminophenol; therefore, 4-hydroxycoumarin is a novel substance capable of producing hydrated electrons. Hydrated electrons undergo transformation in solution, generating reducing hydrogen atoms upon interaction with hydrogen ions. They can also react directly with water molecules to form hydrogen atoms and hydroxyl radicals, or with bisulfite ions to form sulfite ions and hydrogen atoms. The generated hydrogen atoms can combine with hydroxyl radicals to form water molecules, releasing hydrated electrons. Adding surfactants to ionic liquids is a simple method for preparing reverse micelles, which can maintain the lifetime of hydrated electrons for a relatively long time. The hydrated electron component in the formed reverse micelles can be separated by centrifugation, and its activity can be maintained for a certain period. Hydrated electrons can usually be detected by using the absorption spectrum of dye molecules, or by using their strong reducing properties to reduce metal ions and then observing the resulting metal nanoparticles under an electron microscope. Near-infrared spectroscopy (NIR) is the simplest, most direct, and effective technique for studying hydrated electrons; hydrated electron complexes exhibit direct absorption in the 1300-2000 nm near-infrared range. Summary of the Invention
[0003] Purpose of the invention: The purpose of this invention is to provide a hydrated electron solution for degrading pollutants and its application.
[0004] Technical solution: This invention provides a hydrated electron solution for degrading pollutants, wherein the hydrated electron solution is obtained by introducing [Bmim]PF6 and [C]... 16[mim]PF6 was prepared by adding PBS solution dropwise under ultrasonic conditions.
[0005] Furthermore, the ultrasonic conditions are 40 kHz, 120 W, and the ultrasonic time is 1–15 min.
[0006] Furthermore, the [Bmim]PF6, [C 16 The ratio of PF6 to PBS solution is 1.5:2.0-10.0:2.0-10.0.
[0007] Furthermore, the [Bmim]PF6, [C 16 The ratio of PF6 to PBS solution was 1.5:2.0:6.0.
[0008] Furthermore, the reaction temperature during preparation is 30–60°C.
[0009] Furthermore, the PBS solution also includes potassium iodide.
[0010] Furthermore, the concentration range of the potassium iodide is 0.01–100 μmol / L.
[0011] Furthermore, the concentration of potassium iodide is 0.1 μmol / L.
[0012] Furthermore, the [Bmim]PF6 and PBS solutions need to be deoxygenated with nitrogen before use.
[0013] Furthermore, the pollutant is a perfluorinated compound or a bromate compound.
[0014] This invention also provides a method for degrading pollutants in water, comprising adding a phosphate buffer solution and potassium iodide to water containing perfluorinated compounds or bromate compounds, and then adding [Bmim]PF6 and [C] to the prepared solution under ultrasonic conditions. 16 [mim]PF6 is sufficient.
[0015] Furthermore, the pH of the phosphate buffer solution is 2–10.
[0016] This invention selects [Bmim]PF6 (1-butyl-3-methylimidazolium hexafluorophosphate) as the nitrogen carbene precursor, and [C 16 [mim]PF6 is a surfactant. A phosphate buffer solution (PBS) with pH=6 is added to it while sonicating. The sonication allows the substances in the system to come into full contact with the PBS solution, forming an ionic liquid reverse micelle system with a W / O structure containing hydrated electrons.
[0017] Beneficial effects: Compared with the prior art, the present invention has the following outstanding advantages: The ionic liquid reverse micelles containing strongly reducing hydrated electrons prepared by the preparation method of the present invention can be used to degrade pollutants. The preparation method is simple and the preparation cost is low. Moreover, after adding potassium iodide, the degradation rate of perfluorooctanoic acid and bromate can reach more than 75% and 91%, respectively. Attached Figure Description
[0018] Figure 1 [Bmim]PF6-[C 16 Preparation of reverse micelles in PF6-PBS;
[0019] Figure 2 [Bmim]PF6-[C 16 Near-infrared spectrum of PF6-PBS ionic liquid reverse micelles;
[0020] Figure 3 [Bmim]PF6-[C 16 [mim]PF6-PBS ionic liquid reverse micelle reduced gold nanoparticles by transmission electron microscopy;
[0021] Figure 4 [Bmim]PF6-[C 16 Elemental analysis and characterization of gold nanoparticles reduced by reverse micelles in PF6-PBS ionic liquid;
[0022] Figure 5 [Bmim]PF6-[C 16 [mim]PF6-PBS ionic liquid reverse micelle degradation of perfluorinated compound products fluoride ion selective electrode standard curve;
[0023] Figure 6 [Bmim]PF6-[C 16 [mim]PF6-PBS ionic liquid reverse micelle degradation of bromate absorption spectrum;
[0024] Figure 7 1. Standard curve of bromate absorption spectrum;
[0025] Figure 8 [Bmim]PF6-[C 16 mim]PF6-PBS ionic liquid reverse micelles [C 16 Trend diagram of the effect of PF6 content on the degradation of bromate;
[0026] Figure 9 [Bmim]PF6-[C 16 [mim]Trend diagram of the effect of water content in PF6-PBS ionic liquid reverse micelles on the degradation of bromate;
[0027] Figure 10 A trend diagram showing the effect of temperature on the degradation of bromate during the reaction process;
[0028] Figure 11 A trend diagram showing the effect of pH on the degradation of bromate during the reaction process;
[0029] Figure 12 A trend diagram showing the effect of initial bromate concentration on bromate degradation;
[0030] Figure 13 [Bmim]PF6-[C 16 [mim]Trend diagram of the effect of potassium iodide concentration on the degradation of bromate in PF6-PBS ionic liquid reverse micelles;
[0031] Figure 14 [Bmim]PF6-[C 16 [mim]Trend chart showing the effect of adding other common anions to PF6-PBS ionic liquid reverse micelles on the degradation of bromate. Detailed Implementation
[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings.
[0033] Example 1 [Bmim]PF6-[C 16 Preparation of PF6-PBS Reverse Micelles
[0034] With [C 16 [Bmim]PF6 is a surfactant, and BmimPF6 is a hydrophobic solvent. [Bmim]PF6 (1.5 mL)-[C] is fixed. 16 The turbidity of the solution was visually observed under the condition of sonication (40KHz, 120W, 15min, 25℃) and PBS solution (pH=6) being added dropwise. (All solutions used were deoxygenated with nitrogen for 30min to reduce the influence of oxygen on the experiment.) Figure 1 The formation process of ionic liquid reverse micelles (IL-RM) is shown. Figure 1 a is directed towards [Bmim]PF6-[C] 16 When PBS solution was added to PF6, a layered structure appeared. After sonication, a uniform and clear state was formed. Figure 1 b, This state indicates the formation of reverse micelles (the amount of PBS solution added is ≤10 μL), followed by turbidity due to the addition of an excess of ionic liquid to the PBS solution (1-c, the amount of PBS solution added is >10 μL). Finally, the [Bmim]PF6-[C] solution was analyzed by adding 6 μL of PBS solution. 16 [mim]PF6-PBS reverse micelles continued to be used for subsequent experiments.
[0035] Example 2 [Bmim]PF6-[C 16 near-infrared spectrum of PF6-PBS reverse micelles
[0036] The above measurements were determined using a Cary 5000 near-infrared (NIR) absorption spectrometer. Figure 1 -b NIR spectrum (see Figure 2 ). Figure 2 1406, 1609, and 1901 cm can be found in the middle. -1 The absorption peak of the hydrated electron complex indicates the successful preparation of hydrated electrons. Other ionic liquids, such as BmimAc and BmimNTf2, do not exhibit obvious NIR absorption peaks.
[0037] Example 3 [Bmim]PF6-[C 16 [mim]Pmission electron microscopy and elemental analysis of gold nanoparticles reduced by reverse micelles in PF6-PBS
[0038] To further confirm [Bmim]PF6-[C 16 The presence of hydrated electrons in [mim]PF6-PBS reverse micelles was used to confirm the formation of gold nanoparticles after adding chloroauric acid to the aqueous phase of PBS. The main steps for preparing ionic liquid reverse micelles are as follows: Weigh 1.4 mg of [C]... 16 Add [Bmim]PF6 to a 50 mL centrifuge tube, then add 1.0 mL of [Bmim]PF6 ionic liquid and 1.0 mL of a 1 mg·mL⁻¹ solution. -1 Add chloroauric acid and shake well. Prepare the reagent by mixing the [Bmim]PF6 ionic liquid and chloroauric acid solution at a volume ratio of 1:1, then sonicate for 15 min, followed by stirring at 4000 rpm. -1 Centrifuge for 15 min to obtain reverse micelles, which then separate into layers. The lower layer of ionic liquid is then placed on an ITO glass plate and dried in a vacuum oven for 24 h. Finally, SEM analysis is performed. Figure 3 ). Figure 3 The generation of gold nanoparticles was clearly observed. Figure 4 The above is the EDS image of the reverse micelles. The EDS measurement results clearly identify the gold nanoparticles.
[0039] Example 4 [Bmim]PF6-[C 16 Application of PF6-PBS Reverse Micelles in the Degradation of Perfluorinated Compounds
[0040] Fluorine products are used in various fields, including traditional industries shifting towards electronics, energy, environmental protection, information technology, and biomedicine. While driving economic growth, they also pose a certain threat to the ecological environment. This example examines the [Bmim]PF6-[C] prepared in Example 1. 16The hydration electrons in PF6-PBS reverse micelles reduce and degrade a novel fluorine-containing environmental pollutant, perfluorooctanoic acid (PFOA). The specific steps are as follows: Prepare a 140 μmol·L⁻¹ solution using a pH 6 phosphate buffer. -1 A perfluorooctanoic acid solution was added to [Bmim]PF6 (1.5 mL)-[C 16 Add 6 μL of prepared perfluorooctanoic acid solution to PF6 (2.0 mg) and sonicate. The fluoride ions generated during degradation were determined using an ion-selective electrode method, and the degradation rate was calculated. Figure 5 The standard curve for the ion-selective potentiometry of fluoride ions is given by: y = -57.22257x + 9.8937, R0 2 =0.9978).
[0041] Based on the measured potential results ( Figure 5 From the fluoride ion standard curve, the fluoride ion concentration of each sample can be obtained, and it is known that the initial concentration of the reagents is 140 μmol·L⁻¹. -1 Perfluorooctanoic acid (PFOA) has 15 fluorine atoms, so the degradation rate can be calculated using the following formula:
[0042]
[0043] The results showed that the hydrated electrons prepared under the above conditions achieved a reduction degradation rate of 75.8% for perfluorooctanoic acid (Table 1).
[0044] Table 1. Results of potentiometric determination of fluoride ions
[0045]
[0046] Example 5 [Bmim]PF6-[C 16 Application of PF6-PBS Reverse Micelles in Bromate Degradation
[0047] 1. [Bmim]PF6-[C 16 [mim]PF6-PBS reverse micelles degrade bromate
[0048] Bromate is a disinfection byproduct and a potential carcinogen, primarily composed of bromides (Br₂). - It is formed by oxidation with ozone. In this example, the degradation of bromate by the reduction of hydrated electrons prepared in Example 1 was investigated. Specifically, potassium bromate solutions of different concentrations were prepared using a phosphate buffer solution with pH = 6, and [Bmim]PF6 (1.5 mL)-[C 16 Add 6 μL of prepared potassium bromate solution to PF6 (2.0 mg) and sonicate to reduce and degrade bromate. The remaining bromate ions react with iodide ions in an acidic medium to form elemental iodine, and react with excess iodide ions to form I3. -Based on this property, ultraviolet spectrophotometry was used to determine the trace bromate content in water. I3 can be used... - The degradation rate of bromate was determined by ultraviolet spectrophotometry at 288 nm and calculated. Figure 6 and Figure 7 The figures show the absorption spectra of bromate at different concentrations in aqueous solution and the standard curve of bromate (y = 20276.38191x + 0.08317, R). 2 =0.998). Preliminary experimental results prove that [Bmim]PF6-[C 16 [mim]PF6-PBS reverse micelles can degrade bromate, and further investigation will be conducted on the relevant factors affecting the degradation rate.
[0049] 2. [C] 16 Effect of PF6 content on bromate degradation rate
[0050] For the investigation [C 16 The effect of [C]PF6 surfactant content on the degradation of bromate was investigated under the hydration electron preparation conditions of Example 1, with different amounts of [C]PF6 surfactant added in the range of 2.0-10.0 mg. 16 [mim]PF6, potassium bromate concentration is 2.08×10 -5 Degradation with mol / L PBS ( Figure 8 The results show that [C] 16 The degradation rate of bromate is relatively high when the [Bmim]PF6 content is 3.8–4.2 mg, with the highest degradation rate observed at a content of 4.0 mg. This indicates that when the [C] content of the same volume of [Bmim]PF6 is high... 16 Excessive PF6 content can limit the size of reverse micelles, thereby reducing the degradation rate of bromate.
[0051] 3. Effect of PBS addition amount on bromate degradation rate
[0052] To investigate the effect of water content on bromate degradation, the effects were examined under the hydration electron preparation conditions of Example 1, with the addition of different amounts of PBS (potassium bromate concentration of 2.08 × 10⁻⁶) ranging from 2.0 to 10.0 μL. -5 Degradation rate of bromate (mol / L) Figure 9 The results showed that [Bmim]PF6-[C 16 The degradation rate of bromate was relatively high when 5-8 μL of PBS was added to PF6, with the highest degradation rate observed when 6.0 μL of PBS was added. This is related to... Figure 8 The reason for the result is the same: when the PBS content in the same volume of [Bmim]PF6 is too high, it will also limit the size of the reverse micelles, thus causing the degradation rate of bromate to decrease.
[0053] 4. Effect of reaction temperature on bromate degradation rate
[0054] To investigate the effect of reaction temperature on the degradation of bromate, the influence of varying ultrasonic temperature within the range of 20-80°C on the bromate degradation rate was examined under the hydration electron preparation conditions of Example 1. 16 The concentration of potassium bromate added to PF6 was 2.08 × 10⁻⁶. -5 Degradation was performed using mol / L PBS solution. Figure 10 The results showed that the reverse micelles prepared at 30–60 °C exhibited a high degradation rate of bromate, with the reverse micelles prepared at 50 °C showing the highest degradation rate of bromate, indicating that the reverse micelle system produced the most hydrated electrons at this temperature.
[0055] 5. Effect of pH on bromate degradation rate during the reaction process
[0056] To investigate the effect of the pH of the reaction system on the degradation of bromate, the influence of the hydrated electrons prepared in Example 1 on the degradation rate of potassium bromate solutions with different initial pH values (2-10) was examined. 16 The concentration of potassium bromate added to PF6 was 2.08 × 10⁻⁶. -5 Degradation was performed using PBS solution with a concentration of mol / L and a pH of 2-10. Figure 11 The results showed that the degradation rate exceeded 70% under acidic and neutral conditions with an initial bromate concentration, decreased under alkaline conditions, and the highest degradation rate was measured at pH 6 of PBS, indicating that the survival hydrated electrons generated by this reverse micelle system were at the highest level.
[0057] 6. Effect of initial bromate concentration on its degradation rate
[0058] To investigate the effect of initial bromate concentration on bromate degradation, the effect of hydrated electrons prepared in Example 1 (with ultrasonic temperature changed to 50℃) on the degradation rate of potassium bromate solutions with different initial concentrations (5–25 μmol / L) was examined. Figure 12 The results showed that the degradation rate exceeded 70% in the initial bromate concentration range of 5.0-25.0 μmol / L, and the highest degradation rate was measured at a bromate concentration of 5.0 μmol / L, indicating that the concentration range of the viable hydrated electrons generated by this reverse micelle system is in the μmol / L range.
[0059] 7. Effect of potassium iodide additive on bromate degradation rate
[0060] The above experiments show that the concentration of viable hydrated electrons generated by the reverse micelle system is in the μmol / L range. It is predicted that higher concentrations of bromate degradation will be inhibited due to the lack of hydrated electrons. To investigate the effect of potassium iodide additive on the bromate degradation rate, 1.5 mL of BmimPF6 + 4 mg C was added at 50℃. 16 While sonicating, 6.0 μL of PBS containing different concentrations of potassium iodide (pH = 6, potassium bromate concentration 2.08 × 10⁻⁶) was added dropwise to mimPF6. -5 mol / L)( Figure 13 ). Figure 13 The results show that the bromate degradation rate reached a maximum of nearly 92% when the potassium iodide additive was 0.1 μmol / L. This may be because trace concentrations of iodide ions may act as hydration electron amplifiers.
[0061] 8. Effects of other common anionic additives on bromate degradation rate
[0062] To investigate the effect of other common anionic additives on the hydrated electron concentration level in reverse micelles, 1.0 μmol / L levels of other common anions (sulfate, sulfite, nitrate, and carbonate) were added to the PBS aqueous solution used in the preparation of reverse micelles to determine the degradation rate of bromate. Figure 14 The results showed that the common anions investigated, such as sulfate, sulfite, nitrate, and carbonate, did not amplify hydrated electrons.
[0063] Given the similar chemical properties of iodide and bromide ions, it can be inferred that bromide ions should also have a similar effect on the amplification of hydrated electrons as iodide ions. However, since bromide ions are a product of the degradation of bromate, they can be considered... Figure 14 The degradation rate without the addition of other anionic hydration electron amplifying agents already includes the amplification effect of bromide ions. Based on the above results, it can be concluded that [Bmim]PF6-[C 16 [mim]PF6 ionic liquid reverse micelles can be used for the reductive degradation of fluorine- and bromate-containing pollutants.
Claims
1. The application of a hydrated electron solution in the degradation of pollutants, characterized in that, The hydrated electron solution, through [Bmim]PF6 and [C 16 [mim]PF6 was prepared by adding PBS solution under ultrasonic conditions, forming an ionic liquid reverse micelle system with a W / O structure containing hydrated electrons; The ultrasonic conditions are 40 kHz, 120 W, and ultrasonic time is 1~15 min; The [Bmim]PF6, [C 16 The ratio of PF6 to PBS solution is 1.5:2.0~10.0:2.0~10.0; The PBS solution also includes potassium iodide; the concentration of potassium iodide is 0.01 ~ 100 μmol / L; The pollutants are perfluorinated compounds or bromate compounds.
2. The application of the hydrated electron solution according to claim 1 in the degradation of pollutants, characterized in that, The reaction temperature during preparation is 30~60 ℃.
3. The application of the hydrated electron solution according to claim 1 in the degradation of pollutants, characterized in that, The [Bmim]PF6 and PBS solutions need to be deoxygenated with nitrogen before use.
4. The application of the hydrated electron solution according to claim 1 in the degradation of pollutants, characterized in that, The application includes the following steps: adding phosphate buffer solution and potassium iodide to water containing perfluorinated compounds or bromate compounds; adding [Bmim]PF6 and [C] to the prepared solution under ultrasonic conditions. 16 [mim]PF6 is sufficient.
5. The application of the hydrated electron solution according to claim 4 in the degradation of pollutants, characterized in that, The pH of the phosphate buffer solution is 2-10.