Method for removing organic pollutants by using metal ions to strengthen permanganate oxidation and coagulation

Abstract

The present application belongs to the technical field of water treatment, and provides a method for removing organic pollutants by using metal ions to strengthen permanganate oxidation and coagulation, which comprises the following steps: (1) adding metal salt capable of releasing metal ions in wastewater to wastewater containing organic pollutants, and then adding permanganate for wastewater treatment; in the wastewater treatment process, the metal ions released by the metal salt in the wastewater will complex with the permanganate, enhance the electrophilic reactivity of the permanganate, and then strengthen the permanganate oxidation to degrade the organic pollutants in the wastewater; the permanganate is finally reduced and converted into colloidal MnO2; (2) adjusting the pH value of the wastewater to 8.0-11.0, adding a flocculant to the wastewater, uniformly mixing, and then fully flocculating and settling to complete the wastewater treatment. The present application can remove the organic pollutants by strengthening the permanganate oxidation, and simultaneously remove the exogenous metal ions, so as to reduce the environmental risk of the exogenous activator.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology and relates to a method for removing organic pollutants by using metal ions to enhance permanganate oxidation coagulation. Background Technology

[0002] Industrial and daily production involves the use of large amounts of organic matter, metals, and compounds containing metal ions, inevitably resulting in the discharge of metal ions and organic pollutants into water bodies. These pollutants pose a significant threat to human health and the ecological environment. Over the past few decades, water treatment technologies such as adsorption, ion exchange, membrane separation, and chemical oxidation have developed rapidly, aiming to address wastewater pollution problems caused by metal ions and organic pollutants.

[0003] Permanganate (Mn(VII)) is often used for simultaneous oxidation and coagulation to remove organic pollutants and metal ions from wastewater due to its dual functions of oxidation and coagulation. Specifically, Mn(VII) and its associated active Mn intermediates, such as Mn(VI) and Mn(V), have strong oxidizing capabilities and can degrade organic pollutants through oxidation. The colloidal MnO2 produced by the oxidation and decomposition of Mn(VII) can play a certain role in coagulation. However, like most oxidants, Mn(VII) has a low oxidizing capacity and is not very effective in removing most organic pollutants. To improve the oxidation efficiency of Mn(VII), various methods have been proposed, such as applying ultrasound, adding reducing agents for activation, and adding carbon materials for activation. However, these methods still have problems such as high energy consumption and complex operation. In particular, the added exogenous activators are difficult to remove effectively from the water body, which can cause secondary pollution to the aquatic environment. In addition, the MnO2 produced by the oxidation and decomposition of Mn(VII) has poor settling properties and cannot effectively remove metal ions from the water body. Therefore, there is an urgent need to develop greener and more efficient technologies for enhancing the oxidation and degradation of organic pollutants by Mn(VII) to achieve efficient degradation of organic pollutants in wastewater and simultaneously remove externally added metal ions, thereby reducing the environmental risks of external activators. Summary of the Invention

[0004] To address the problems of existing technologies that rely on the addition of exogenous activators to enhance permanganate oxidation for the removal of organic pollutants, which result in the difficulty of effectively removing these activators from water bodies and the potential for secondary pollution, this invention provides a method for removing organic pollutants by enhancing permanganate oxidation coagulation with metal ions. This method effectively enhances the ability of permanganate oxidation to remove organic pollutants while simultaneously removing the added metal ions, thereby reducing the environmental risks associated with exogenous activators.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for removing organic pollutants using metal ions-enhanced permanganate oxidation coagulation includes the following steps:

[0007] (1) A metal salt capable of releasing metal ions from the wastewater is added to the wastewater containing organic pollutants, followed by the addition of permanganate for wastewater treatment. During the wastewater treatment process, the metal ions released by the metal salt in the wastewater complex with the permanganate, enhancing the electrophilic reactivity of the permanganate and thus strengthening the oxidative degradation of organic pollutants in the wastewater by the permanganate. The permanganate is eventually reduced and converted into colloidal MnO2. The metal ions released by the metal salt in the wastewater include Zn. 2+ Al 3+ ,Sc 3+ Ni 2+ Mg 2+ Ca 2+ At least one of them;

[0008] In this step, the amount of metal salt added is controlled so that the molar ratio of the metal ions to permanganate in the wastewater is (0.5-1.5):1.

[0009] (2) Adjust the pH value of the wastewater treated in step (1) to 8.0 to 11.0, add flocculant to the wastewater, mix evenly and allow it to fully flocculate and settle, and the wastewater treatment is completed.

[0010] In step (1) of the above method, the dosage of metal salt and permanganate is determined based on the actual water quality of the wastewater containing organic pollutants (e.g., the type and concentration of organic pollutants). Once the water quality is determined, suitable dosages of metal salt and permanganate can be determined experimentally to ensure high degradation efficiency for organic pollutants in the wastewater. Preferably, the dosage of metal salt is controlled to achieve a concentration of 50–150 μmol / L of metal ions in the wastewater.

[0011] In step (2) of the above method, it is preferable to control the amount of flocculant added so that the concentration of flocculant in the wastewater is 0.1 to 2 g / L.

[0012] In step (2) of the above method's technical solution, the flocculant includes at least one of inorganic and organic flocculants. The flocculant is a conventional flocculant in the water treatment field and can be selected according to actual application requirements. For example, feasible inorganic flocculants include aluminum salts, iron salts, etc., commonly including polyaluminum sulfate, polyaluminum chloride, polyalumina, polyferric chloride, polyferric sulfate, etc.; feasible organic flocculants include anionic organic flocculants, cationic flocculants, and nonionic flocculants, commonly including sodium polyacrylate, carboxymethyl cellulose, polyvinylimide, polycyclopropane, polyacrylamide, etc.

[0013] In step (1) of the above method's technical solution, the metal salt refers to a water-soluble salt containing the above-mentioned metal ions, such as sulfates, nitrates, chlorides, etc. containing the above-mentioned metal ions.

[0014] In step (1) of the above method, the treatment pH value of the wastewater in step (1) is determined according to the water quality of the wastewater containing organic pollutants. For example, the treatment pH value of the wastewater can be determined according to the type and concentration of organic pollutants in the wastewater containing organic pollutants. Generally speaking, the pH value of the wastewater is controlled within the range of 5.0 to 10.0. For example, in step (1), after adding a metal salt that can release metal ions into the wastewater containing organic pollutants, the pH value of the wastewater is adjusted to 5.0 to 10.0, and then permanganate is added for wastewater treatment.

[0015] In step (1) of the above method, the wastewater treatment time is determined based on the water quality of the wastewater containing organic pollutants. For example, the wastewater treatment time can usually be determined based on the type and concentration of organic pollutants in the wastewater. Generally, treatment is sufficient until the removal rate of organic pollutants in the wastewater reaches equilibrium. Typically, the wastewater treatment time does not exceed 90 minutes; for example, the wastewater treatment time can be controlled to be 30–90 minutes.

[0016] In step (2) of the above method, during the flocculation and sedimentation process, the metal ions introduced by adding metal salts in step (1), as well as the metal ions originally present in the wastewater, can be adsorbed or incorporated into the surface or interior of the colloidal MnO2 generated in step (1). The added flocculant can promote the flocculation and sedimentation of colloidal MnO2, thereby achieving the purpose of effectively removing exogenous metal ions. The amount of flocculant added and the flocculation and sedimentation time are determined according to the water quality of the wastewater after treatment in step (1), with the principle of effectively removing the metal ions introduced into the wastewater by adding metal salts. Generally, the flocculation and sedimentation time can be 0.5 to 3 hours.

[0017] In the above-described method, the organic pollutants include at least one of quinolones, sulfonamides, phenols, and carbamazepines, but are not limited to these types of organic pollutants. Quinolones typically include enrofloxacin, ciprofloxacin, levofloxacin, moxifloxacin, etc.; sulfonamides typically include sulfadiazine, sulfisoxazole, sulfadiazine, sulfamethoxazole, sulfathiazole, etc.; phenols typically include phenol, bisphenol A, catechol, naphthol, etc.; and carbamazepines typically include carbamazepine, oxcarbazepine, escricarbazepine, 2-hydroxycarbamazepine, etc.

[0018] In the above technical solution, the permanganate refers to the permanganate used in the prior art to degrade organic pollutants, specifically water-soluble permanganate, such as common sodium permanganate and potassium permanganate.

[0019] This invention demonstrates through experiments that its method can effectively resist the influence of aquatic substrates on the degradation of organic pollutants. For example, it can overcome the degradation of Cl, a common pollutant in water. - HCO3 - PO4 3- Ca 2+ Mg 2+ The coexisting matrix with humic acid and other organic pollutants has an adverse effect on the degradation process. Therefore, in practical applications, the method of this invention can be used to treat organic pollutants containing Cl. - HCO3 - PO4 3- Ca 2+ Mg 2+ Wastewater containing at least one of the organic pollutants, namely humic acid.

[0020] The main technical principles of this invention are as follows:

[0021] This invention involves adding a metal salt that releases metal ions into wastewater containing organic pollutants. The metal ions released by the metal salt in the water can complex with permanganate, enhancing the electrophilic reactivity of permanganate and thus strengthening its ability to oxidize and degrade organic pollutants in the wastewater, thereby improving the degradation efficiency of permanganate for organic pollutants. After oxidizing and degrading organic pollutants, permanganate is reduced and converted into colloidal MnO2. After permanganate oxidizes organic pollutants and is reduced to colloidal MnO2, metal ions in the wastewater are adsorbed or incorporated onto the surface or interior of the colloidal MnO2. In other words, the metal ions released by the introduced metal salt, after enhancing the electrophilic reactivity of permanganate, can bind to the colloidal MnO2 generated during wastewater treatment. Based on this, this invention further promotes the flocculation and sedimentation of colloidal MnO2 by adding a flocculant, thereby simultaneously removing exogenous metal ions introduced by the addition of the metal salt and MnO2 generated during wastewater treatment.

[0022] Compared with the prior art, the technical solution provided by the present invention has the following beneficial technical effects:

[0023] 1. This invention provides a method for removing organic pollutants by using metal ions to enhance permanganate oxidation coagulation. The method first adds a metal salt that can release metal ions into the wastewater containing organic pollutants, and then adds permanganate for wastewater treatment. During the wastewater treatment process, the metal ions released by the metal salt in the wastewater will complex with the permanganate, enhancing the electrophilic reactivity of the permanganate, thereby strengthening the permanganate's ability to oxidize and degrade organic pollutants in the wastewater. The permanganate is eventually reduced and converted into colloidal MnO2. Afterwards, the pH of the wastewater is adjusted to 8.0-11.0, and a flocculant is added to the wastewater for flocculation and sedimentation to remove metal ions and colloidal MnO2 from the wastewater. On the one hand, this invention effectively enhances the electrophilic reactivity of permanganate by introducing metal ions released from the metal salt, thereby significantly strengthening the ability of permanganate to oxidize and degrade organic pollutants. On the other hand, after enhancing the electrophilic reactivity of permanganate, the metal ions released by the added metal salt can bind to colloidal MnO2 generated during wastewater treatment. This invention promotes the flocculation and sedimentation of colloidal MnO2 by adding a flocculant, thus achieving the simultaneous removal of the introduced exogenous metal ions and the MnO2 generated during wastewater treatment. This invention solves the problem in existing methods that enhance the oxidation efficiency of permanganate by adding exogenous activators, where the exogenous activators are difficult to remove effectively from water bodies, easily causing secondary water pollution, and effectively reduces the environmental risks of exogenous activators.

[0024] 2. The reagent used in the method of the present invention to enhance the oxidation efficiency of permanganate against organic pollutants is a water-soluble metal salt that can release metal ions. Such chemical reagents are readily available and inexpensive. In addition, the method of the present invention is simple to operate, has low energy consumption, and does not require complex equipment, which helps to reduce wastewater treatment costs and save energy.

[0025] 3. Experiments have shown that, compared to adding permanganate alone, the method of the present invention, by introducing specific metal ions into the wastewater through the addition of metal salts, can accelerate the degradation of organic pollutants by permanganate within a pH range of 5.0 to 10.0, thereby improving the degradation efficiency of organic pollutants. The method of the present invention has the advantage of a wide range of applicable pH values ​​for wastewater.

[0026] 4. Experiments have confirmed that the method of this invention has good removal capabilities for a variety of organic pollutants, including p-hydroxybenzoic acid, p-hydroxybenzaldehyde, phenol, bisphenol A, bisphenol F, 2,4-dibromophenol, resorcinol, 2,4-dichlorophenol, and trichlorophenol. In particular, compared with the case where no metal salt is added to introduce metal ions, the method of this invention significantly improves the removal rate of the above-mentioned organic pollutants. The method of this invention can be used to degrade a variety of organic pollutants and has a wide range of applicability to different types of pollutants.

[0027] 5. Experiments have demonstrated that the method described in this invention, while enhancing the degradation efficiency of permanganate for organic pollutants, can also efficiently remove exogenously added metal ions. The removal rate of exogenously added metal ions can reach 83% to 100%. By adjusting the type and dosage of flocculant according to the actual water quality, the efficient removal of exogenous metal ions can be achieved, effectively reducing the impact of exogenous activators on water quality. This solves the problem that exogenous activators added in existing technologies are difficult to remove effectively from water bodies and easily cause secondary pollution to the water environment.

[0028] 6. Experimental verification shows that the method of this invention still has a good degradation effect on organic pollutants in the presence of an aquatic matrix. For example, the method of this invention can overcome the common Cl- in water bodies. - HCO3 - PO4 3- Ca 2+ Mg 2 + It exhibits good stability and high application value because it can withstand adverse effects from coexisting matrices such as humic acid on the degradation process. Attached Figure Description

[0029] Figure 1 The curves showing the change of C / C0 over time during step (1) of the degradation of p-methylphenol in Examples 1 and Comparative Examples 1-2 are shown.

[0030] Figure 2 This refers to step (1) of Example 2, which involves using different metal ions to enhance the degradation of p-methylphenol by Mn(VII) and the pollutant removal rate and first-order reaction rate constant (k). obs min -1 ).

[0031] Figure 3 The curves showing the change of C / C0 over time during step (1) of Example 3 and Comparative Example (2) when p-methylphenol is degraded are shown.

[0032] Figure 4 This refers to the removal rate of different organic pollutants in step (1) of Examples 4 and Comparative Examples 3-4.

[0033] Figure 5 Figures a to c show the removal rates of bisphenol A, p-bromophenol, and 2,4-dichlorophenol under different pH conditions in step (1) of Example 5 and Comparative Example 5, respectively.

[0034] Figure 6 This is a graph showing the effect of metal ions on the open-circuit voltage of Mn(VII) in Example 6.

[0035] Figure 7This is a graph showing the effect of metal ions on the reduction potential of Mn(VII) in Example 6.

[0036] Figure 8 In Example 7, Mn(VII) is used to counteract Al. 3+ The influence of the NMR spectrum on the test results.

[0037] Figure 9 It is Al in Example 7 3+ Experimental results related to enhancing the mechanism of Mn(VII) oxidation and degradation of organic pollutants.

[0038] Figure 10 The results show the effect of common coexisting matrices in water on the first-order reaction rate constant of p-methylphenol degradation in Example 8.

[0039] Figure 11 Figure a is a photograph of the wastewater during the coagulation treatment process in step (2) of Example 9. Figure 11 Figure b shows the concentration of metal ions in the wastewater before and after step (2) of Example 9, as well as the removal rate of metal ions by step (2).

[0040] Figure 12 The different types of flocculants in step (2) of Example 10 affect Al 3+ Removal rate.

[0041] Figure 13 The removal rate of p-methylphenol after different treatment times in step (1) of Example 11.

[0042] Figure 14 Example 12 shows the effect of different doses of flocculant on Al in step (2). 3+ Removal rate. Detailed Implementation

[0043] The following examples further illustrate the method for removing organic pollutants using metal ion-enhanced permanganate oxidation coagulation provided by the present invention. It should be noted that the following examples are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above description are still within the scope of protection of the present invention.

[0044] In the following examples and comparative examples, the permanganate (Mn(VII)) used is specifically potassium permanganate, and the pH value of the simulated wastewater or each solution is adjusted using NaOH solution and / or H2SO4 solution.

[0045] Example 1

[0046] This embodiment provides a method for removing organic pollutants using metal ions-enhanced Mn(VII) oxidation coagulation, specifically using p-methylphenol as a model pollutant and employing Al... 3+ The method for enhancing the removal of organic pollutants by Mn(VII) oxidation and coagulation includes the following steps:

[0047] (1) Dissolve p-methylphenol in water to form a 10 μmol / L solution, and use this solution as simulated wastewater. Add AlCl3 to the simulated wastewater to make Al... 3+ The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) was 1:1. After adding Mn(VII), the reaction was carried out under stirring for 30 min to degrade p-cresol. Mn(VII) was reduced to colloidal MnO2. Samples were taken at 0 min, 2.5 min, 5 min, 10 min, 20 min, and 30 min after adding Mn(VII). The reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution to the samples. The concentration of p-cresol in the samples was then analyzed by high performance liquid chromatography and recorded as concentration C. The initial concentration of p-cresol was recorded as C0. C / C0 was calculated, and the C / C0 change curve over time was plotted.

[0048] (2) Adjust the pH of the wastewater treated in step (1) to 10.0, then add the flocculant polyaluminum chloride to make the concentration of polyaluminum chloride in the wastewater 1 g / L, stir at 350 r / min for 5 min, and let it stand for 30 min after stopping stirring to remove Al from the wastewater. 3+ Combined with MnO2, wastewater treatment is completed.

[0049] Comparative Example 1

[0050] The operation of this comparative example is basically the same as that of Example 1, except that Mn(VII) is not added in step (1), the timing is started after adjusting the pH value of the simulated wastewater to 7.8, and the reaction is carried out for 30 minutes under stirring conditions.

[0051] Comparative Example 2

[0052] The operation of this comparative example is basically the same as that of Example 1, except that AlCl3 is not added in step (1).

[0053] Example 1, Comparative Examples 1-2: Step (1) During the degradation of p-methylphenol, the C / C ratio over time is shown in the curves. Figure 1 As shown, by Figure 1 It can be seen that after 30 minutes of reaction, Al alone... 3+Almost no p-methylphenol can be removed; Mn(VII) alone removes 53% of p-methylphenol, while Al... 3+ The addition of [a substance] can accelerate the degradation of p-methylphenol by Mn(VII), increasing the removal rate of p-methylphenol to 96%, indicating that the method described in this invention can accelerate the degradation of organic pollutants by Mn(VII).

[0054] Example 2

[0055] In this embodiment, a method for enhancing the removal of organic pollutants by Mn(VII) oxidation coagulation using different metal ions is provided. The effects of different metal ions on the efficiency of Mn(VII) in degrading organic pollutants are investigated. The steps are as follows:

[0056] (1) Dissolve p-methylphenol in water to form a 10 μmol / L solution, and use this solution as simulated wastewater. Take 6 portions of simulated wastewater and add NiCl2, ZnCl2, CaCl2, MgCl2, AlCl3 and ScCl3 to each portion respectively, so that the metal ions (NiCl2, ZnCl2, CaCl2, MgCl2, AlCl3 and ScCl3) are added to each portion respectively. 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ and Sc 3+ The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the metal ion concentration (Ni). 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ and Sc 3+ The molar ratio of Mn(VII) to Mn(VII) was 1:1. After adding Mn(VII), the reaction was carried out under stirring for 30 min to degrade p-cresol. Mn(VII) was reduced to colloidal MnO2. The case of adding only Mn(VII) served as a blank control group. A sample was taken 30 min after adding Mn(VII), and 0.5 mol / L hydroxylamine hydrochloride solution was added to the sample to terminate the reaction. The concentration of p-cresol in the sample was then analyzed by high performance liquid chromatography and recorded as concentration C. The initial concentration of p-cresol was recorded as C0. The removal rate of p-cresol [(C-C0) / C0×100%] and the first-order reaction rate constant (k) were calculated. obs min -1 The result is as follows Figure 2 As shown.

[0057] (2) Adjust the pH value of each wastewater treated in step (1) to 10.0, then add flocculant polyaluminum chloride to each wastewater to a concentration of 1 g / L. Stir at 350 r / min for 5 min, and then let it stand for 30 min after stopping stirring to remove metal ions (Ni) from each wastewater. 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ Or Sc 3+ ) and MnO2, to complete wastewater treatment.

[0058] Depend on Figure 2 It can be seen that, after 30 minutes of reaction in step (1), compared to the blank control group without any metal ions, the addition of Ni... 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ and Sc 3+ Subsequently, the six ions can promote the degradation of p-methylphenol by Mn(VII) to varying degrees, and the k-value of p-methylphenol by Mn(VII) is... obs All were improved to varying degrees, with the promoting effect manifested as follows: Zn 2+ >Al 3+ >Sc 3+ >Ni 2+ >Mg 2+ >Ca 2+ The results indicate that these metal ions can all promote the degradation of organic pollutants by Mn(VII), and the promoting effect is related to the type of metal ion. Considering the cost and potential environmental impact of chemical reagents, in practical applications, appropriate metal ions can be selected by comprehensively considering factors such as water quality, water characteristics, and cost to enhance the degradation of organic pollutants by Mn(VII).

[0059] Example 3

[0060] In this embodiment, p-methylphenol is used as a model pollutant, and Al is employed. 3+ Enhanced Mn(VII) oxidation coagulation for the removal of organic pollutants, and Al 3+ The effect of the molar ratio of Mn(VII) to Mn(VII) on the degradation performance of pollutants is shown in the following steps:

[0061] (1) Dissolve p-methylphenol in water to form a 10 μmol / L solution, and use this solution as the simulated wastewater. Take 5 portions of the simulated wastewater and add AlCl3 to each portion to make Al... 3+The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to each simulated wastewater to control the Al content. 3+ The molar ratios of Mn(VII) to Mn(VII) were 0.5:1, 0.8:1, 1:1, and 1.5:1. After adding Mn(VII), the reaction was carried out under stirring for 30 min to degrade p-cresol, and Mn(VII) was reduced to colloidal MnO2. Samples were taken at 0 min, 2.5 min, 5 min, 10 min, 20 min, and 30 min after adding Mn(VII). The reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution to the samples. The concentration of p-cresol in the samples was then analyzed by high performance liquid chromatography and recorded as concentration C. The initial concentration of p-cresol was recorded as C0. The C / C0 ratio was calculated, and the C / C0 change curve over time was plotted.

[0062] (2) Adjust the pH value of each wastewater treated in step (1) to 10.0, and then add flocculant polyaluminum chloride to each wastewater to make the concentration of polyaluminum chloride in each wastewater 1 g / L. Stir at 350 r / min for 5 min, and after stopping stirring, let it stand for 30 min to remove Al from each wastewater. 3+ Combined with MnO2, wastewater treatment is completed.

[0063] In this embodiment and Comparative Example 2, the C / C ratio changes over time during the degradation of p-methylphenol in step (1) are shown in the curves. Figure 3 As shown, Figure 3 "Al" 3+ The data "Mn(VII) molar ratio of 0:1" represents the test results of Comparative Example 2. Figure 3 It can be seen that with Al 3+ As the molar ratio of metal ions to Mn(VII) gradually increased from 0:1 to 1.5:1, the removal rate of p-methylphenol gradually increased from 53% to 98%. This indicates that the molar ratio of metal ions to Mn(VII) affects the degradation effect of organic pollutants. In practical applications, the ideal removal rate of organic pollutants can be achieved by adjusting the molar ratio of metal ions to Mn(VII) after the wastewater quality is determined.

[0064] Example 4

[0065] In this embodiment, AI is provided. 3+ The method of enhancing Mn(VII) oxidation coagulation to remove different organic pollutants was investigated, and Al was examined. 3+ The steps to enhance the ability of Mn(VII) oxidation coagulation to remove different organic pollutants are as follows:

[0066] (1) p-hydroxybenzoic acid, p-hydroxybenzaldehyde, phenol, bisphenol A, bisphenol F, 2,4-dibromophenol, resorcinol, 2,4-dichlorophenol, and trichlorophenol were dissolved in water to prepare solutions with a concentration of 10 μmol / L, which were then used as simulated wastewater. AlCl3 was added to each simulated wastewater to make Al... 3+ The concentration of Mn(VII) in each simulated wastewater was 100 μmol / L. The pH of each simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) was 1:1. After adding Mn(VII), the reaction was carried out under stirring for 30 min to degrade various organic pollutants. Mn(VII) was reduced to colloidal MnO2. A sample was taken 30 min after adding Mn(VII), and the reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution. The concentration of organic pollutants in the sample was then analyzed by high performance liquid chromatography and recorded as concentration C. The initial concentration of organic pollutants was recorded as C0, and the removal rate of organic pollutants was calculated as (C0-C) / C0×100%.

[0067] (2) Adjust the pH value of each wastewater treated in step (1) to 10.0, and then add flocculant polyaluminum chloride to each wastewater to make the concentration of polyaluminum chloride in each wastewater 1 g / L. Stir at 350 r / min for 5 min, and after stopping stirring, let it stand for 30 min to remove Al from each wastewater. 3+ Combined with MnO2, wastewater treatment is completed.

[0068] Comparative Example 3

[0069] The operation of this comparative example is basically the same as that of Example 4, except that Mn(VII) is not added in step (1), and the timing is started after adjusting the pH value of the simulated wastewater to 7.8, and the reaction is carried out for 30 minutes under stirring conditions.

[0070] Comparative Example 4

[0071] The operation of this comparative example is basically the same as that of Example 4, except that AlCl3 is not added in step (1).

[0072] Figure 4 The removal rates of different organic pollutants in step (1) of Examples 4 and Comparative Examples 3-4 are determined by... Figure 4 It can be seen that Al alone 3+ The removal efficiency for all nine pollutants was very low (removal rate <5%). Mn(VII) alone could degrade these nine pollutants to varying degrees, but the removal rate was related to the type of pollutant. (The text then abruptly shifts to a seemingly unrelated topic: "Adding Al...") 3+Subsequently, the removal rates of the above nine pollutants by Mn(VII) were improved to varying degrees, indicating that the method of the present invention can be used to degrade a variety of organic pollutants and has a wide range of applications.

[0073] Example 5

[0074] In this embodiment, AI is provided. 3+ A method for enhancing the removal of different organic pollutants by Mn(VII) oxidation and coagulation was investigated, focusing on the effect of wastewater pH on Al. 3+ The steps to enhance the effect of Mn(VII) oxidation coagulation on the removal capacity of organic pollutants are as follows:

[0075] (1) Bisphenol A, p-bromophenol, and 2,4-dichlorophenol were dissolved in water to prepare solutions with a concentration of 10 μmol / L, which were then used as simulated wastewater. AlCl3 was added to each simulated wastewater to make Al... 3+ The concentration of Mn(VII) in each simulated wastewater was 100 μmol / L. The pH values ​​of each simulated wastewater were adjusted to 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0, respectively. Then, Mn(VII) was added to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) was 1:1. After adding Mn(VII), the reaction was carried out under stirring for 30 min to degrade various organic pollutants. Mn(VII) was reduced to colloidal MnO2. A sample was taken 30 min after adding Mn(VII), and the reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution. The concentration of organic pollutants in the sample was then analyzed by high performance liquid chromatography and recorded as concentration C. The initial concentration of organic pollutants was recorded as C0, and the removal rate of organic pollutants was calculated as (C0-C) / C0×100%.

[0076] (2) Adjust the pH value of each wastewater treated in step (1) to 10.0, and then add flocculant polyaluminum chloride to each wastewater to make the concentration of polyaluminum chloride in each wastewater 1 g / L. Stir at 350 r / min for 5 min, and after stopping stirring, let it stand for 30 min to remove Al from each wastewater. 3+ Combined with MnO2, wastewater treatment is completed.

[0077] Comparative Example 5

[0078] The operation of this comparative example is basically the same as that of Example 5, except that AlCl3 is not added in step (1).

[0079] Figure 5 Figures a through c show the removal rates of bisphenol A, p-bromophenol, and 2,4-dichlorophenol in step (1) of Example 5 and Comparative Example 5 under different pH conditions, respectively. Figure 5 It can be seen that Al 3+Within a pH range of 5.0–10.0, Mn(VII) can promote the degradation of three organic pollutants—bisphenol A, p-bromophenol, and 2,4-dichlorophenol—to varying degrees, especially when the pH of the simulated wastewater is close to the pK value of the organic pollutants. a When the value is , Al 3+ The improved effect of Mn(VII) in degrading organic pollutants indicates that metal ions can enhance the degradation of organic pollutants by Mn(VII) within a wide pH range. Therefore, the method of this invention has a wide applicable pH range for wastewater. In practical applications, a suitable pH value can be selected within the range of pH 5.0 to 10.0 based on factors such as the type and concentration of pollutants in the wastewater to achieve the desired removal effect of organic pollutants.

[0080] Example 6

[0081] In this embodiment, the effects of various metal ions on the electrophilic reactivity of Mn(VII) were tested by electrochemistry.

[0082] Electrochemical tests and analyses were performed using an electrochemical workstation. A 0.5 mol / L sodium sulfate solution was used as the electrolyte, and a glassy carbon electrode, a platinum wire electrode, and a saturated calomel electrode were used as the working electrode, counter electrode, and reference electrode, respectively. Electrochemical tests were conducted in environments containing 0.2 mmol / L Mn(VII) and 0.4 mmol / L metal ions (Sc). 3+ Al 3+ Zn 2+ Ni 2+ Ca 2+ or Mg 2+ The tests were performed in a solution of Mn(VII) or in a separate solution of 0.2 mmol / L Mn(VII), with Mn(VII) added during the test. The pH of the solution was maintained at 7.8, and the open-circuit voltage change was recorded from 0 to 2500 seconds. Cyclic voltammetry curves of Mn(VII) in the presence and absence of metal ions were recorded at a scan rate of 0.2 V / s within a voltage range of -0.8 V to +1.0 V.

[0083] The effect of metal ions on the open-circuit voltage of Mn(VII) is as follows: Figure 6 As shown. By Figure 6 It can be seen that metal ions affect the voltage of Mn(VII) on the electrode surface. With the addition of metal ions, the voltage value of Mn(VII) increases to varying degrees, indicating that the presence of metal ions increases the oxidation potential of Mn(VII). The degree of change in oxidation potential is related to the type of metal ion. The effect of metal ions on the cyclic voltammetry curve of Mn(VII) is shown in the figure below. Figure 7 As shown. By Figure 7It can be seen that the reduction potential of Mn(VII) is around +0.094V. With the introduction of metal ions, the reduction potential of Mn(VII) will shift positively by 0.329 to 0.429V, indicating that the addition of metal ions will increase the reduction potential of Mn(VII) and the electrophilic reactivity of Mn(VII) will increase with the addition of metal ions.

[0084] Example 7

[0085] In this embodiment, the mechanism of metal ion-enhanced Mn(VII) oxidation and degradation of organic pollutants was investigated through various experiments.

[0086] 1. Prove the complexation effect between metal ions and Mn(VII).

[0087] With Al 3+ For example, using 27 Al nuclear magnetic resonance (NMR) spectroscopy analysis of Mn(VII) and Al 3+ The interaction between them was tested during NMR analysis. 3+ NMR spectra were obtained after combining Al with other materials at molar ratios of 1:3, 1:1, and 2:1, while individual Al was also tested. 3+ The NMR spectrum.

[0088] Figure 8 It is Mn(VII) against Al 3+ The influence of NMR spectrum test results, Al 3+ It exhibits strong resonance around -0.70 ppm, with the introduction of Mn(VII) and Mn(VII) / Al 3+ With the increase of the molar ratio, a trend emerged in the resonance shifting towards a higher field. 27 The chemical shift in Al NMR is affected by the p electrons and orbital radius of Al. Figure 8 The offset in Al indicates 3+ There is an interaction between Al and Mn(VII), which affects the coordination environment of Al and provides a suitable environment for Al. 3+ The complexation with Mn(VII) provides direct evidence.

[0089] 2. Quenching Experiment

[0090] Sodium pyrophosphite (PP) and methanol (MeOH) were used as quenchers for Mn(III), Mn(V), and Mn(VI), respectively, to investigate the contributions of these three active Mn intermediates to the degradation of organic pollutants. The specific procedures are as follows:

[0091] (1) Dissolve p-methylphenol in water to form a solution with a concentration of 10 μmol / L, and use this solution as simulated wastewater.

[0092] AlCl3 was added to the simulated wastewater, causing Al... 3+ The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) and a quencher were added simultaneously to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) is 1:1, and the reaction is carried out under stirring for 30 min.

[0093] Three experimental groups and one blank control group were set up. The first experimental group used PP as the quencher at a concentration of 5 mmol / L in the simulated wastewater. The second experimental group used PP as the quencher at a concentration of 20 mmol / L in the simulated wastewater. The third experimental group used MeOH as the quencher at a concentration of 100 mmol / L in the simulated wastewater. No quencher was added to the blank control group.

[0094] Samples were taken at 0 min, 2.5 min, 5 min, 10 min, 20 min, and 30 min after the addition of Mn(VII). The reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution to the samples. The concentration of p-cresol in the samples was then analyzed by high-performance liquid chromatography (HPLC) and denoted as concentration C. The initial concentration of p-cresol was denoted as C0. The C / C0 ratio was calculated, and a curve showing the change of C / C0 over time was plotted. The results are shown below. Figure 9 As shown in Figure a.

[0095] (2) Add AlCl3 to the simulated wastewater to make Al 3+ The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) and quencher PP were added simultaneously to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) is 1:1, and the reaction is carried out for 20 min under stirring.

[0096] One experimental group and one control group were set up. In the experimental group, the concentration of quencher PP in the simulated wastewater was 20 mmol / L. In the control group, AlCl3 was not added, and Mn(VII) in the experimental group was replaced with Mn(III). Figure 9 The experimental group was sampled at 0 min, 5 min, 10 min, and 20 min after the addition of Mn(VII), while the control group was sampled at 20 min after the addition of Mn(VII). The reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution to each sample. UV full scan analysis was performed on each sample. The changes in UV full scan absorbance were used to investigate the reaction between Mn(VII) and the quencher, as well as the formation of Mn(III)-PP. The results are shown in Figure b. Figure 9 As shown in Figure b.

[0097] (3) Add AlCl3 to the simulated wastewater to make Al 3+ The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) and quencher MeOH were added simultaneously to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) is 1:1, and the reaction is carried out under stirring for 30 min.

[0098] One experimental group and two control groups were set up. In the experimental group, the concentration of the quencher MeOH in the simulated wastewater was 100 mmol / L; no AlCl3 was added in the first control group; and no AlCl3 or MeOH was added in the second control group. Samples were taken at 15 min and 30 min after the addition of Mn(VII) in the experimental group and the first control group, respectively, and at 30 min after the addition of Mn(VII) in the second control group. The reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution to the samples. UV full scan analysis was performed on each sample. The reaction between Mn(VII) and the quencher was investigated based on the changes in UV full scan absorbance. The results are as follows: Figure 9 As shown in Figure c.

[0099] The degree of inhibition of pollutant degradation after adding the appropriate quencher indicates the contribution of the active Mn intermediate quenched by the quencher to pollutant degradation. Figure 9 As shown in Figure a, the addition of 5 mmol / L and 20 mmol / L PP had almost no effect on the degradation of p-cresol, but the addition of 100 mmol / L MeOH partially inhibited the degradation of p-cresol; after 30 min of reaction, the removal rate of p-cresol decreased from 96% to 72%. Figure 9 As shown in Figure b, Mn(III)-PP exhibits a strong absorption peak at 258 nm, but PP / Al 3+ The Mn(VII) system does not exhibit an absorption peak at 258 nm during the degradation of p-cresol, indicating that Mn(III)-PP is not generated during this degradation process. Figure 9 As shown in Figure c, within a 30-minute reaction time, MeOH hardly reacts with Mn(VII) and causes significant Mn(VII) consumption, but Al... 3+ The presence of [a specific substance] promotes the reaction between Mn(VII) and MeOH, thereby causing absorbance changes in the wavelength range of 200–600 nm. The above experimental results indicate that Mn(III) is not an Al [a specific substance]. 3+The Mn(VII) system is an active oxide species and does not participate in the degradation of p-methylphenol. The inhibitory effect of the addition of MeOH on the degradation of p-methylphenol may be due to the consumption of Mn(VII) by MeOH itself. The roles of Mn(V) and Mn(VI) need to be further analyzed in conjunction with other experiments.

[0100] 3. Probe experiment

[0101] Methyl phenyl sulfoxide (PMSO) was used as a probe for Mn(V) and Mn(VI) to further analyze Al. 3+ The effect on the formation of Mn(V) and Mn(VI). The principle of using PMSO as a probe for Mn(V) and Mn(VI) is as follows: Mn(V) and Mn(VI) can oxidize PMSO through an oxygen atom transfer mechanism to generate the characteristic reaction product methyl phenyl sulfone (PMSO2), while Mn(VII) and Mn(III) cannot oxidize PMSO, nor can they lead to the formation of PMSO2. The operation of the probe experiment is as follows:

[0102] PMSO was dissolved in water to form a 10 μmol / L solution, which was then used as a water sample for testing. AlCl3 was added to the water sample to adjust the pH to 7.8, followed by the addition of Mn(VII). The reaction was carried out under stirring for 30 min. A sample was taken, and the reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution. The concentrations of PMSO and PMSO2 in the sample were analyzed by high-performance liquid chromatography (HPLC). The PMSO removal rate and the yield of PMSO2 produced per unit volume of PMSO consumed were calculated. The results are as follows: Figure 9 As shown in Figure d.

[0103] A total of four experimental groups and one control group were conducted. In the four experimental groups, the amount of AlCl3 added was controlled to make Al... 3+ The concentrations of Mn(VII) in the water samples were 50, 80, 100, and 150 μmol / L, respectively, and the concentration of Mn(VII) in the water samples was controlled at 100 μmol / L. In the control group, no AlCl3 was added, and the concentration of Mn(VII) in the water samples was controlled at 100 μmol / L.

[0104] Depend on Figure 9 As can be seen from the d-graph, Al 3+ The addition of [a specific ingredient] does not promote the degradation of PMSO by Mn(VII), and the degradation rate of PMSO remains around 80%, while the yield of PMSO2 remains close to 100%. [The last sentence appears to be incomplete and possibly refers to a different topic.] Figure 6 , 7 From 9, we can know that Al 3+ The addition of Al does not promote the participation of active Mn intermediates (Mn(III), Mn(V), and Mn(VI)) in the degradation of organic pollutants. 3+The enhanced degradation of pollutants caused by this phenomenon mainly stems from Al 3+ Effect of Al on the electrophilic reactivity of Mn(VII) 3+ It enhances the electrophilic reactivity of Mn(VII).

[0105] Example 8

[0106] In this embodiment, common coexisting matrices in water bodies are investigated, including ions (Cl). - HCO3 - PO4 3- Ca 2+ Mg 2+ ) and humic acid on Al 3+ The effects of the / Mn(VII) system on the degradation of methylphenol are illustrated in the following steps:

[0107] p-Cresol was dissolved in water to form a 10 μmol / L solution, which was used as the simulated wastewater. Multiple portions of the simulated wastewater were taken, and AlCl3 was added to each portion to increase the concentration of Al... 3+ The concentration in the simulated wastewater was 100 μmol / L, and then ions (Cl) were added to each simulated wastewater. - HCO3 - PO4 3- Ca 2+ Mg 2+ Mn(VII) and humic acid were added to adjust the concentrations of each ion to 0.5 mmol / L and 1.0 mmol / L, respectively, and the concentrations of humic acid to 20 mg / L and 10 mg / L, respectively. The pH of each simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the Al content. 3+ The molar ratio of methylphenol to Mn(VII) was 1:1, and the reaction was carried out under stirring for 30 min. During the reaction, samples were taken at regular intervals, and 0.5 mol / L hydroxylamine hydrochloride solution was added to the samples to terminate the reaction. The concentration of p-methylphenol in the samples was then analyzed by high performance liquid chromatography. Based on the concentration of p-methylphenol at different time points, the first-order reaction rate constant (k) of p-methylphenol degradation under different concentrations of added ions and humic acid was fitted. obs min -1 The result is as follows Figure 10 As shown.

[0108] Depend on Figure 10 It can be seen that adding Cl - It will not affect AI 3+ The / Mn(VII) system degrades p-methylphenol by k obs Add 0.5 mmol / L of Ca 2+ Mg 2+ It will not affect AI 3+The / Mn(VII) system degrades p-methylphenol by k obs With Ca 2+ Mg 2+ Increased concentration will increase Al 3+ The / Mn(VII) system degrades p-methylphenol by k obs Add 0.5 mmol / L and 1.0 mmol / L HCO3. - and PO4 3- It will improve AI to varying degrees. 3+ The / Mn(VII) system degrades p-methylphenol by k obs Adding 10 mg / L of humic acid will increase Al 3+ The / Mn(VII) system degrades p-methylphenol by k obs However, adding 20 mg / L of humic acid slightly inhibits Al 3+ The / Mn(VII) system degrades p-methylphenol. Figure 10 The results show that Al 3+ The / Mn(VII) system can resist the influence of most water matrix on the degradation efficiency of organic pollutants by the method of the present invention. Some water matrix can even promote the degradation of organic pollutants. The method of the present invention has strong anti-interference ability.

[0109] Example 9

[0110] In this embodiment, the flocculation effect of flocculant on MnO2 generated during the degradation of organic pollutants in the metal ion / Mn(VII) system and on externally added metal ions was investigated. The steps are as follows:

[0111] (1) Dissolve p-methylphenol in water to form a 10 μmol / L solution, and use this solution as simulated wastewater. Take 6 portions of simulated wastewater and add NiCl2, ZnCl2, CaCl2, MgCl2, AlCl3 and ScCl3 to each portion respectively, so that the metal ions (NiCl2, ZnCl2, CaCl2, MgCl2, AlCl3 and ScCl3) are added to each portion respectively. 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ and Sc 3+ The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the metal ion concentration (Ni). 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ and Sc 3+The molar ratio of Mn(VII) to Mn(VII) is 1:1. After adding Mn(VII), the mixture is reacted for 30 min under stirring to degrade methylphenol. Mn(VII) is reduced to generate colloidal MnO2.

[0112] (2) Adjust the pH value of each wastewater treated in step (1) to 10.0, and then add flocculant polyaluminum chloride to make the concentration of polyaluminum chloride in each wastewater 1g / L. Stir at 350r / min for 5min, stop stirring and let it stand for 30min. Take water samples 2cm below the water surface and filter them with a 0.45μm filter membrane. Use an atomic absorption spectrometer to determine the concentration of metal ions in the water samples and calculate the removal rate of metal ions. Observe the state of the wastewater during the coagulation process and take pictures.

[0113] Figure 11 Figure a shows a photograph of the wastewater during the coagulation process in step (2) when AlCl3 is added in step (1). The "oxidized" portion represents the wastewater treated in step (1), the "flocculated" portion represents the wastewater after stirring at 350 r / min for 5 min, the first and second sediments represent the wastewater after settling for 15 min and 30 min respectively after stirring was stopped, and the "filtered" portion represents the wastewater after a water sample taken 2 cm below the water surface was filtered through a 0.45 μm filter membrane. Figure 11 As shown in Figure a, with the addition of flocculant, the MnO2 produced by the oxidation of Mn(VII) will continuously flocculate and eventually settle.

[0114] Figure 11 Figure b shows the metal ions (Ni) in the wastewater before and after treatment in step (2). 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ and Sc 3+ The concentration of ) and the removal rate of metal ions in step (2). From Figure 11 As shown in Figure b, the method in this embodiment affects Ca. 2 + Mg 2+ Ni 2+ Zn 2+ Al 3+ and Sc 3+ The removal rates were 94.45%, 97.36%, 99.25%, 96.88%, 98.26%, and 97.36%, respectively. This indicates that the method described in this invention can reduce the impact of exogenous activators on water quality while enhancing the degradation of pollutants by Mn(VII), thus exhibiting significant environmental benefits.

[0115] Example 10

[0116] This embodiment provides a method for removing organic pollutants using metal ions-enhanced Mn(VII) oxidation coagulation, specifically using p-methylphenol as a model pollutant and Al... 3+ To investigate the effect of flocculant type on metal ion removal, using model metal ions as an example, the steps are as follows:

[0117] (1) Dissolve methylphenol in water to form a 10 μmol / L p-methylphenol solution, and use this solution as simulated wastewater. Take 4 portions of simulated wastewater and add AlCl3 to each portion to make Al... 3+ The concentration of Mn(VII) in the simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) is 1:1. After adding Mn(VII), the mixture is reacted for 30 min under stirring to degrade methylphenol. Mn(VII) is reduced to generate colloidal MnO2.

[0118] (2) Adjust the pH value of each simulated wastewater treated in step (1) to 10.0, and then add flocculants polyaluminum chloride, polyaluminum sulfate, polyferric chloride and polyferric sulfate to each simulated wastewater respectively, so that the concentration of flocculants in the wastewater is 1 g / L. Stir at 350 r / min for 5 min, and after stopping stirring, let it stand for 30 min to remove Al from the wastewater. 3+ Combined with MnO2, wastewater treatment is completed.

[0119] Figure 12 Step (2) involves adding different flocculants to treat the Al in the simulated wastewater. 3+ The removal rate is determined by Figure 12 It can be seen that the four flocculants—polyaluminum chloride, polyaluminum sulfate, polyferric chloride, and polyferric sulfate—have different effects on Al. 3+ The removal rates were 98.26%, 98.69%, 97.56% and 99.44%, respectively, indicating that the different flocculants used in step (2) had a high removal effect on exogenous metal ions.

[0120] Example 11

[0121] This embodiment provides a method for removing organic pollutants using metal ions-enhanced Mn(VII) oxidation coagulation, specifically using p-methylphenol as a model pollutant and Al... 3+ Using model metal ions, the effect of reaction time in step (1) on the degradation effect of pollutants was investigated. The steps are as follows:

[0122] (1) Dissolve p-methylphenol in water to form a 10 μmol / L solution, and use this solution as the simulated wastewater. Take 4 portions of the simulated wastewater and add AlCl3 to each portion to make Al...3+ The concentration of Mn(VII) in each simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the Al content. 3+ The molar ratio of Mn(VII) to Mn(VII) was 1:1. After adding Mn(VII), the reaction was carried out under stirring for 30 min, 45 min, 60 min, and 90 min, respectively, to degrade methylphenol. Mn(VII) was reduced to MnO2. Samples were taken at 30 min, 45 min, 60 min, and 90 min after adding Mn(VII). The reaction was terminated by adding 0.5 mol / L hydroxylamine hydrochloride solution to the samples. The concentration of p-methylphenol in the samples was then analyzed by high performance liquid chromatography and recorded as concentration C. The initial concentration of p-methylphenol was recorded as C0. The p-methylphenol removal rate was calculated as (C0-C) / C0×100%.

[0123] (2) Adjust the pH value of each simulated wastewater treated in step (1) to 10.0, then add flocculant polyaluminum chloride to each simulated wastewater to make the flocculant concentration in the wastewater 1 g / L, stir at 350 r / min for 5 min, stop stirring and let it stand for 30 min to remove Al from the wastewater. 3+ Combined with MnO2, wastewater treatment is completed.

[0124] Figure 13 This refers to the removal rate of p-methylphenol in step (1) under different wastewater treatment time conditions. Figure 13 It can be seen that after 30 min, 45 min, 60 min, and 90 min of reaction, the removal rates of p-methylphenol were 96%, 98.73%, 100%, and 100%, respectively. In practical applications, the appropriate reaction time can be selected according to the type and concentration of organic pollutants in the wastewater to achieve the ideal removal effect of organic pollutants.

[0125] Example 12

[0126] This embodiment provides a method for removing organic pollutants using metal ions-enhanced Mn(VII) oxidation coagulation, specifically using p-methylphenol as a model pollutant and Al... 3+ To investigate the effect of flocculant dosage on the removal efficiency of metal ions, the following steps were taken:

[0127] (1) Dissolve p-methylphenol in water to form a 10 μmol / L solution, and use this solution as the simulated wastewater. Take 4 portions of the simulated wastewater and add AlCl3 to each portion to make Al... 3+ The concentration of Mn(VII) in each simulated wastewater was 100 μmol / L. The pH of the simulated wastewater was adjusted to 7.8, and then Mn(VII) was added to control the Al content. 3+The molar ratio of Mn(VII) to Mn(VII) is 1:1. After adding Mn(VII), the mixture is reacted under stirring for 30 min to degrade methylphenol. Mn(VII) is reduced to MnO2.

[0128] (2) Adjust the pH value of each simulated wastewater treated in step (1) to 10.0, and then add different doses of polyaluminum chloride to each simulated wastewater to make the flocculant concentrations in the wastewater 0.1 g / L, 0.5 g / L, 1 g / L and 2 g / L respectively. Stir at 350 r / min for 5 min, and after stopping stirring, let it stand for 30 min to remove Al from the wastewater. 3+ Combined with MnO2, wastewater treatment is completed.

[0129] Figure 14 After step (2), the Al in the simulated wastewater is treated. 3+ The removal rate. (By...) Figure 14 It can be seen that when the flocculant dosage is 0.1 g / L, 0.5 g / L, 1 g / L and 2 g / L, it has an effect on Al 3+ The removal rates were 83.33%, 94.31%, 98.26%, and 100%, respectively. Therefore, in practical applications, the appropriate dosage of flocculant can be selected based on factors such as the type and concentration of metal ions in the raw wastewater and the type and concentration of externally added metal ions to achieve the desired removal effect of metal ions in wastewater.

Claims

1. A method for removing organic pollutants by enhancing permanganate oxidation coagulation with metal ions, characterized in that, Includes the following steps: (1) Add ScCl3, a metal salt that can release metal ions from wastewater, to the wastewater containing organic pollutants to adjust the pH of the wastewater to 7.

8. Then add permanganate for wastewater treatment. During the wastewater treatment process, the metal ions released by the metal salt in the wastewater will complex with the permanganate, enhancing the electrophilic reactivity of the permanganate, thereby strengthening the oxidation and degradation of organic pollutants in the wastewater by the permanganate. The permanganate is eventually reduced and converted into colloidal MnO2. The metal ions released by the metal salt in the wastewater are ScCl3. 3+ ; In this step, the dosage of metal salt is controlled so that the molar ratio of the metal ions to permanganate in the wastewater is (0.8~1.5):1; the dosage of metal salt is controlled so that the concentration of the metal ions in the wastewater reaches 50~150 μmol / L. (2) Adjust the pH value of the wastewater treated in step (1) to 8.0~11.0, add flocculant to the wastewater so that the concentration of flocculant in the wastewater is 0.1~2 g / L, mix evenly and allow it to fully flocculate and settle, and the wastewater treatment is completed.

2. The method for removing organic pollutants by utilizing metal ions-enhanced permanganate oxidation coagulation according to claim 1, characterized in that, The flocculant in step (2) includes at least one of inorganic and organic flocculants.

3. The method for removing organic pollutants by utilizing metal ions-enhanced permanganate oxidation coagulation according to claim 1, characterized in that, In step (1), the wastewater treatment time is controlled to be 30~90 min.

4. The method for removing organic pollutants by utilizing metal ions-enhanced permanganate oxidation coagulation according to claim 1, characterized in that, In step (2), the flocculation and sedimentation time is controlled to be 0.5~3 h.

5. The method for removing organic pollutants by utilizing metal ions-enhanced permanganate oxidation coagulation according to claim 1, characterized in that, The organic pollutants include at least one of the following: quinolones, sulfonamides, phenols, and carbamazepines.

Images