A method for removing organic pollutants in wastewater by using chromium-catalyzed persulfate oxidation

Abstract

This invention provides a method for removing organic pollutants from wastewater using chromium-catalyzed persulfate oxidation. The method includes: adding persulfate to wastewater containing both chromium and organic pollutants, stirring the reaction at room temperature, and oxidizing and degrading the organic pollutants; wherein the chromium is one or both of trivalent chromium ions and complexed trivalent chromium. This method is simple to operate, requires no complex equipment, and can be used rapidly at room temperature and pressure, demonstrating significant pollutant removal efficiency. Cr(III) and EDTA chelating agents are commonly used chemical reagents in various industries such as electroplating. Using Cr(III) complex wastewater as a reactant to treat organic pollutants not only removes the organic pollutants but also breaks down the stable Cr(III) complex, which is beneficial for subsequent chromium removal. This method has broad application prospects and is easily industrialized.

Description

Technical Field

[0001] This invention belongs to the field of wastewater pollution treatment technology, specifically relating to a method for removing organic pollutants from wastewater using chromium-catalyzed persulfate oxidation. Background Technology

[0002] Chromium is one of the most common industrial materials, frequently found in wastewater from industries such as textiles, electroplating, metallurgy, and paint, posing a significant threat to ecological and environmental safety. However, many polluted wastewaters contain not only chromium but also other organic pollutants. Common treatment methods for chromium-containing wastewater include chemical methods, electrolysis, and adsorption, but these are relatively costly. Organic pollutants are generally removed using the Fenton reaction.

[0003] The Fenton reaction is a commonly used advanced oxidation technology that has been widely applied in recent years for industrial wastewater treatment, soil and groundwater remediation, and advanced wastewater treatment. Compared to other advanced oxidation technologies, it has advantages such as simple operation, low cost, no need for complex equipment, and environmental friendliness. The traditional Fenton reaction involves reacting H₂O₂ with Fe... 2+ The mixture, through catalytic decomposition, produces HO·, which can be used for complex breaking and organic matter removal in chromium-containing wastewater. Chromium, as a transition metal with multiple redox states, can also catalyze the production of free radicals from H2O2. However, the Fenton reaction requires a relatively narrow pH range (pH = 2.8–3.2), and its application in practical processes is limited by issues such as large sludge volume, low H2O2 utilization rate, susceptibility to coexisting substances in water, and easy discoloration after effluent production.

[0004] Persulfate is a strong oxidizing agent. After activation, it can generate free radicals such as H₂O· and sulfate radicals, and can also react with singlet oxygen (…). 1 Non-radical pathways such as O2 and electron transfer degrade pollutants, making them less susceptible to interference from coexisting substances in water and more selective for target pollutants. In recent years, they have been widely studied as an alternative to the traditional Fenton reaction.

[0005] Existing literature on "persulfates for C1-containing compounds" - Chapter 6 of the paper "Experimental Study on Degradation of Dyes in Cr(VI)-Containing Water" discloses the effective removal of high concentrations of organic matter using the strong oxidizing power of the Cr(VI) / PMS oxidation system, which can be used for the removal of organic matter from chromium-containing organic wastewater. However, Cr(VI) is toxic, and its concentration does not change after the oxidation reaction, requiring the addition of H2O2 to reduce it to a lower valence state of chromium. This organic matter removal method requires the additional addition of H2O2 after the oxidation reaction to reduce Cr(VI), making the process complex. Furthermore, the literature does not conduct catalytic PMS research on common trivalent chromium ions and chromium complexes in solution. Summary of the Invention

[0006] Many industrial wastewaters (such as electroplating wastewater) contain not only Cr(III) but also a large amount of chelating agents, such as natural organic matter, citrate, oxalate, EDTA, etc. Cr(III) easily forms Cr(III)-complexes with organic ligands, which are more stable than free Cr(III). Common treatment methods are difficult to break the complexes, which increases the difficulty of treating chromium-containing wastewater.

[0007] To address the problems existing in the prior art, this invention provides a method for removing organic pollutants from wastewater by catalytic oxidation of persulfate with trivalent chromium. This method is simple to operate, has a high organic pollutant removal rate and fast removal speed, a wide pH range, and is easy to industrialize.

[0008] A method for removing organic pollutants from wastewater by chromium-catalyzed persulfate oxidation includes: adding persulfate to wastewater containing both chromium and organic pollutants, stirring the reaction at room temperature, and oxidizing and degrading the organic pollutants.

[0009] The chromium is one or both of trivalent chromium ions (Cr(III)) and complexed trivalent chromium.

[0010] When treating organic pollutant wastewater using this method, if the chromium in the water is in the form of free trivalent chromium ions, the free Cr(III) will react with PMS to form cage-like molecules, hindering the catalytic reaction. When chromium complexes with organic ligands, the formation of cage-like molecules can be slowed down. Therefore, preferably, the chromium is in the complexed trivalent chromium state.

[0011] Preferably, the organic ligand of the complexed trivalent chromium is one or more of oxalate, citrate, and ethylenediaminetetraacetic acid (EDTA). More preferably, it is ethylenediaminetetraacetic acid. That is, the complexed trivalent chromium is chromium ethylenediaminetetraacetic acid (Cr(III)-EDTA).

[0012] As a further preferred embodiment, the molar ratio of chromium to organic ligand in the complexed trivalent chromium is 1:0.5 to 1:2. Even more preferably, it is 1:1. Excessive addition of organic ligands will bind to organic pollutants, hindering the degradation reaction; while insufficient addition of ligands will cause free Cr(III) to react with PMS to form cage-like molecules, impeding the degradation reaction.

[0013] Preferably, the organic pollutant is one or more of Acid Red 73 dye, p-chlorophenol, tetracycline hydrochloride, and bisphenol A. More preferably, it is one or two of Acid Red 73 dye and bisphenol A.

[0014] Preferably, the persulfate is one or both of potassium peroxymonosulfate and potassium perdisulfate (PDS). Potassium peroxymonosulfate is more preferred. Potassium peroxymonosulfate (PMS) is more readily activated by catalysts than perdisulfate, generating a variety of active oxides.

[0015] As a further preferred option, potassium persulfate (PMS) is added in the form of an aqueous solution; wherein the concentration of potassium persulfate (PMS) is 0.4 mol / L.

[0016] Preferably, the amount of persulfate added to the wastewater to be treated is 2.5–10 mmol / L. More preferably, it is 4–6 mmol / L. Even more preferably, it is 5 mmol / L.

[0017] Preferably, the concentration of chromium in the wastewater to be treated is 5–100 mg / L; in this technical solution, chromium refers to the elemental chromium. More preferably, it is 10–50 mg / L. Even more preferably, it is 25 mg / L.

[0018] Preferably, the concentration of organic pollutants in the wastewater to be treated is 10–100 mg / L. More preferably, it is 30–60 mg / L. Even more preferably, it is 50 mg / L.

[0019] Preferably, the pH value of the wastewater to be treated is 3 to 9. More preferably, it is 4 to 6. Even more preferably, it is 5.

[0020] In the method for removing organic pollutants from wastewater by chromium-catalyzed persulfate oxidation of the present invention, when Cr(III) complexes with ethylenediaminetetraacetic acid (EDTA), the active site binding to PMS shifts from Cr to the terminal oxygen of the EDTA ligand. Through hydrogen bonding, electrons are transferred from PMS to the EDTA-Cr(III) ligand, promoting the oxidation of PMS to SO5. ·- SO5 ·- It can rapidly generate S2O8 through self-reaction. 2- SO4 2- and 1 O2 can efficiently degrade organic pollutants coexisting in water, while simultaneously breaking down Cr(III) complexes.

[0021] The method of this invention, when used to treat organic dye wastewater, achieved a removal efficiency of over 96.3% for 50 mg / L Acid Red dye using EDTA-Cr(III) within 1 hour. Simultaneously, the Cr(III) complex was broken down, facilitating further wastewater treatment. Applying this method to the catalytic oxidation degradation of organic pollutants effectively improves the pollutant degradation rate, has a wide applicable pH range, stable performance, and is suitable for a broad range of pollutants.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] This invention presents a method for removing organic pollutants from wastewater using chromium-catalyzed persulfate oxidation. The method is simple to operate, requires no complex equipment, and can be used rapidly at room temperature and pressure, demonstrating significant pollutant removal efficiency. Cr(III) and EDTA chelating agents are commonly used chemical reagents in various industries, including electroplating. Using Cr(III) complex wastewater as a reactant to treat organic pollutants not only removes the pollutants but also breaks down the stable Cr(III) complex, facilitating subsequent chromium removal. This method has broad application prospects and is easily industrialized.

[0024] The method of the present invention is simple to operate, can directly utilize the ethylenediaminetetraacetic acid complexed chromium in the wastewater, treat waste with waste, has low cost, and has high practical value. Attached Figure Description

[0025] Figure 1 Comparison of the effects of different Cr(III) complexes on the removal of Acid Red 73 by PMS;

[0026] Figure 2 Comparison of the effects of Cr(III)-EDTA-catalyzed PMS on the removal of different pollutants;

[0027] Figure 3 The paramagnetic resonance spectra of the Cr(III) / PMS reaction system with 5,5-dimethyl-1-pyrrolline-N-oxide (DMPO) and 2,2,6,6-tetramethylpiperidine (TEMP) as trapping agents are shown below.

[0028] (a) represents DMPO-HO· and DMPO-SO4 in the water system. - The atlas of ·;

[0029] (b) represents DMPO-O2 in the methanol system. - • Atlas;

[0030] (c) represents TEMP- in the water system. 1 O2 spectrum;

[0031] Figure 4 The paramagnetic resonance spectra of the Cr(III)-EDTA / PMS reaction system with 5,5-dimethyl-1-pyrrolline-N-oxide (DMPO) and 2,2,6,6-tetramethylpiperidine (TEMP) as trapping agents are shown below.

[0032] (a) represents DMPO-HO· and DMPO-SO4 in the water system. - The atlas of ·;

[0033] (b) represents DMPO-O2 in the methanol system. - • Atlas;

[0034] (c) represents TEMP- in the water system. 1 O2 spectrum;

[0035] Figure 5 The optimized Cr(III)-EDTA / PMS structure. Detailed Implementation

[0036] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0037] Raw materials used in the examples:

[0038] Potassium persulfate (analytical grade) was purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China);

[0039] Disodium ethylenediaminetetraacetate dihydrate (analytical grade) was purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China);

[0040] Chromium(III) nitrate nonahydrate (analytical grade) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, China);

[0041] Potassium persulfate (analytical grade) was purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China).

[0042] The water used in the experiment was ultrapure water (resistivity ≥ 18.2 MΩ·cm). -1 ).

[0043] The aqueous solution of disodium ethylenediaminetetraacetate used below is prepared by dissolving disodium ethylenediaminetetraacetate dihydrate in water.

[0044] The following Cr(III)-EDTA complex solution was prepared according to the following procedure:

[0045] A chromium nitrate aqueous solution (Cr(III) concentration of 100 mg / L) and a disodium ethylenediaminetetraacetate aqueous solution (concentration of 1.9232 mol / L) were mixed at a molar ratio of chromium ions (Cr(III)) to ethylenediaminetetraacetate ions of 1:1 to obtain a mixed solution. The pH of the mixed solution was then adjusted to 5.0 with H2SO4 solution and NaOH solution, and kept in a water bath at 60-70℃ for 1 h. After incubation in the dark for 48 h, a Cr(III)-EDTA complex solution was obtained, in which the chromium (Cr(III)) concentration was 50 mg / L.

[0046] Example 1

[0047] Acid Red 73 (AR73) is a widely used and difficult-to-degrade azo dye, therefore it is used as the treatment target (organic pollutant to be treated) in this embodiment.

[0048] Add 50 mL of Acid Red 73 aqueous solution (AR73 concentration of 100 mg / L) and 50 mL of chromium nitrate aqueous solution (Cr(III) concentration of 50 mg / L) to a 150 mL Erlenmeyer flask to simulate wastewater containing both chromium and organic pollutants. The wastewater contains 50 mg / L Acid Red 73 and 25 mg / L Cr(III). Adjust the pH of the wastewater to 5.0 using H₂SO₄ and NaOH solutions, and add 0.4 mol / L potassium persulfate aqueous solution to achieve a concentration of 5 mmol / L. Seal the Erlenmeyer flask and place it in a constant temperature shaking chamber. Stir and vibrate at 150 rpm at 25°C for 3 hours to allow for catalytic degradation.

[0049] Example 2

[0050] Add 50 mL of Acid Red 73 aqueous solution (100 mg / L) and 50 mL of Cr(III)-EDTA complex solution (50 mg / L) to a 150 mL Erlenmeyer flask to simulate wastewater containing both chromium and organic pollutants. The wastewater contained 50 mg / L of Acid Red 73 and 25 mg / L of Cr(III). Adjust the pH of the wastewater to 5.0 using H₂SO₄ and NaOH solutions, and add 0.4 mol / L potassium persulfate aqueous solution to achieve a concentration of 5 mmol / L. Seal the Erlenmeyer flask and place it in a constant temperature shaking chamber. Stir and vibrate at 150 rpm at 25°C for 3 hours to allow for catalytic degradation.

[0051] Comparative Examples 1-2

[0052] Add 50 mL of Acid Red 73 aqueous solution (100 mg / L) and 50 mL of chromium nitrate aqueous solution or Cr(III)-EDTA complex solution (Cr(III) concentration of 50 mg / L in both solutions) to two 150 mL Erlenmeyer flasks to simulate wastewater containing both chromium and organic pollutants. The concentrations of Acid Red 73 and Cr(III) in the two wastewater solutions were 50 mg / L and 25 mg / L, respectively. Adjust the pH of the wastewater to 5.0 using H₂SO₄ and NaOH solutions, and add hydrogen peroxide (H₂O₂) solution (9.79 mol / L) to achieve a concentration of 20 mmol / L. Seal the Erlenmeyer flasks and place them in a constant temperature shaking chamber at 25°C with stirring and shaking at 150 rpm for 3 hours.

[0053] Comparative Examples 3-4

[0054] Add 50 mL of Acid Red 73 aqueous solution (100 mg / L) and 50 mL of chromium nitrate aqueous solution or Cr(III)-EDTA complex solution (Cr(III) concentration of 50 mg / L in both solutions) to two 150 mL Erlenmeyer flasks respectively. The mixed solution simulates wastewater containing both chromium and organic pollutants. In both wastewater solutions, the concentration of Acid Red 73 is 50 mg / L and the concentration of Cr(III) is 25 mg / L. Adjust the pH of the wastewater to 5.0 with H2SO4 solution and NaOH solution, and add potassium persulfate (PDS) aqueous solution (0.15 mol / L) to make its concentration in the wastewater 5 mmol / L. After sealing the Erlenmeyer flasks, place them in a constant temperature shaking chamber and stir and shake at 150 rpm at 25 °C for 3 hours for catalytic degradation.

[0055] Comparative Example 5

[0056] Add 50 mL of ultrapure water and 50 mL of Acid Red 73 dye aqueous solution (100 mg / L) to a 150 mL Erlenmeyer flask to simulate wastewater containing organic pollutants; the concentration of Acid Red 73 in the wastewater is 50 mg / L. Adjust the pH of the wastewater to 5.0 with H2SO4 solution and NaOH solution, and add potassium persulfate aqueous solution (0.4 mol / L) to make its concentration in the wastewater 5 mmol / L. After sealing the Erlenmeyer flask, place it in a constant temperature shaking incubator and stir and shake at 150 rpm at 25 °C for 3 hours for catalytic degradation.

[0057] Comparative Example 6

[0058] Add 50 mL of Acid Red 73 aqueous solution (100 mg / L), 25 mL of disodium ethylenediaminetetraacetate aqueous solution (1.9232 mol / L), and 25 mL of ultrapure water to a 150 mL Erlenmeyer flask to simulate wastewater containing both disodium ethylenediaminetetraacetate and organic pollutants; the concentration of Acid Red 73 in the wastewater is 50 mg / L. Adjust the pH of the wastewater to 5.0 with H2SO4 and NaOH solutions, and add potassium persulfate aqueous solution (0.4 mol / L) to achieve a concentration of 5 mmol / L in the wastewater. Seal the Erlenmeyer flask and place it in a constant temperature shaking incubator. Stir and shake the flask at 150 rpm at 25 °C for 3 hours for catalytic degradation.

[0059] Performance Test Example 1

[0060] For Examples 1 and 2, and Comparative Examples 1-6, after the reaction, the samples were taken out and filtered through a 0.45 μm filter membrane. The absorbance was immediately measured at 508 nm using a UV-Vis spectrophotometer. The remaining concentration and removal rate of dye AR73 were calculated based on the concentration standard curve of dye AR73 at 508 nm. The catalytic performance of different systems was investigated using the removal rate of Acid Red 73 in aqueous solution. The results are shown in Table 1. Table 1 shows that PMS in Comparative Example 5 has a certain oxidizing ability and can directly degrade organic pollutants. The AR73 removal rate was 20.3% after 180 min of reaction. In contrast, the removal rate of AR73 by Cr(III) / PMS in Example 1 was only 17.0%. This may be because the positively charged Cr(III) combines with the negatively charged PMS, which to some extent hinders the activation and decomposition of PMS. However, when Cr(III) complexed with EDTA (Example 2), the removal rate of AR73 increased to 97.5%, while the activation effect of EDTA alone on PMS in Comparative Example 6 was not obvious. In Example 2, the original light purple color of the Cr(III)-EDTA solution faded after the removal reaction, indicating that Cr(III)-EDTA effectively activated PMS to generate reactive oxygen species (ROS) and also underwent complex breakdown, thus facilitating subsequent chromium treatment.

[0061] Table 1 Comparison of AR73 removal rates by different systems

[0062]

[0063]

[0064] Performance Test Example 2

[0065] Following the preparation process of the Cr(III)-EDTA complex (solution), Cr(III)-oxalic acid complex and Cr(III)-citric acid complex were prepared using sodium oxalate and sodium citrate as chelating agents, respectively. Then, following the catalytic degradation process of Example 2, Cr(III)-EDTA complex, Cr(III)-oxalic acid complex, and Cr(III)-citric acid complex were used as catalysts in the experimental group, with chromium nitrate as the control group. The effects of different chelating agents and the absence of chelating agents on the removal rate of AR73 were investigated. The results are as follows: Figure 1 As shown. Figure 1 The effect of different chelating agents on the removal rate of Acid Red 73 was investigated. Results showed that sodium oxalate achieved a removal rate of 19.5% for AR73, while sodium citrate achieved a removal rate of 15.4%, which was not significantly different from the removal effect in the control group (no chelating agent added). EDTA-2Na showed the best removal rate and effect, therefore, EDTA-2Na was selected as the most suitable chelating agent.

[0066] Performance Test Example 3

[0067] Following the preparation process of the Cr(III)-EDTA complex (solution), the molar ratio of Cr(III) to EDTA-2Na was adjusted to 1:0, 1:0.5, 1:1, 1:1.5, 1:2, and 0:1, resulting in Cr(III)-EDTA complexes with different compositions. The effect of the concentration ratio of Cr(III) to EDTA-2Na during complexation (different compositions) on the AR73 removal rate was investigated according to the experimental steps of Example 2. The results are shown in Table 2. Table 2 shows the effect of different concentration ratios of Cr(III) to EDTA-2Na during complexation on the removal rate of Acid Red 73. The results indicate that when the concentration ratio is less than 1:1, the AR73 removal rate gradually increases with the increase of EDTA-2Na dosage. Cr(III) can complex with EDTA, reducing the formation of cage-like molecules with PMS and hindering the catalytic reaction. When the concentration ratio is 1:1, the removal rate reaches a maximum of 97.5%. If the amount of EDTA-2Na is further increased, EDTA will bind with AR73, which will affect the removal rate of AR73. Therefore, the concentration ratio of Cr(III) to EDTA-2Na complexation is selected to be 1:1.

[0068] Table 2. Removal rate of AR73 at different concentration ratios of Cr(III) complexed with EDTA-2Na

[0069]

[0070]

[0071] Performance Test Example 4

[0072] Under the selected optimal concentration ratio of Cr(III) to EDTA-2Na complexation (a molar ratio of Cr(III) to EDTA-2Na of 1:1), the effect of different PMS dosages on the removal rate of AR73 was investigated according to the experimental procedure of Example 2 (see Table 3). Table 3 shows the effect of different PMS dosages on the removal rate of Acid Red 73. The results show that the removal rate of AR73 gradually increases with the increase of PMS dosage, but the removal rate reaches 97.5% at a dosage of 5 mmol / L. Further increasing the dosage does not significantly change the removal effect, and a large PMS dosage results in high cost. Therefore, 5 mmol / L was selected as the optimal PMS dosage.

[0073] Table 3. Removal rate of AR73 at different PMS dosages

[0074] Performance Test Example 5

[0075] Following the experimental steps of Example 2, the removal of AR73 at different pH values ​​(3, 5, 7, 9, 11) was investigated (the pH of a 50 mg / L AR73 solution is approximately 6.8), and the results are shown in Table 4. Table 4 shows that the removal rate of AR73 is extremely high under acidic and neutral conditions, indicating that Cr(III)-EDTA can effectively activate PMS, generating reactive oxygen species to degrade pollutants. When pH > 7, the removal rate of AR73 gradually decreases with increasing pH, indicating a decline in its activity. Therefore, the suitable pH for this method is 3–9.

[0076] Table 4. Removal rate of AR73 under different pH conditions

[0077] PMS dosage (mmol / L) Removal rate (%) 1 36.8 2.5 72.6 5 97.5 7.5 98.2 10 98.4

[0078]

[0079]

[0080] Performance Test Example 6

[0081] To investigate the broad applicability of Cr(III) complex-activated PMS for the removal of organic pollutants, this experiment selected four different pollutants: AR73, bisphenol A, p-chlorophenol, and tetracycline hydrochloride. The Cr(III)-EDTA complex was used as a catalyst, and degradation experiments were conducted on these pollutants according to the experimental steps in Example 2. The results are as follows: Figure 2 As shown. By Figure 2As can be seen, the Cr(III)-EDTA complex can effectively activate PMS and has a good degradation effect on different pollutants. Therefore, when Cr(III)-EDTA is present in wastewater (such as electroplating wastewater), this method can be used directly to remove the organic pollutants present in the wastewater.

[0082] Performance Test Example 7

[0083] To investigate the reaction mechanism, 5,5-dimethyl-1-pyrrole-N-oxide (DMPO) and 2,2,6,6-tetramethylpiperidine (TEMP) were used as trapping agents. Paramagnetic resonance (PMR) spectroscopy was employed to determine the active substances in the reaction between Cr(III) / PMS and Cr(III)-EDTA / PMS systems. The results are as follows: Figure 3 and 4 As shown. Figure 3 As shown, only a small amount was detected in the Cr(III) / PMS system. 1 O2 and O2 - ·, but no H2O· or SO42- were detected. - The formation of · is consistent with its poor degradation effect on pollutants. From Figure 4 As can be seen, unlike Cr(III), Cr(III)-EDTA can effectively activate PMS to produce a more obvious effect. 1 O2 is used to degrade pollutants.

[0084] The structure of Cr(III)-EDTA after PMS adsorption was further optimized using density functional theory (DFT) calculations. Calculations were performed using Gaussian software with the PBE0 function. Geometric optimization and frequency calculations used the def2-SVP basis set to determine the optimal geometry for each compound. Single-point energy calculations used the larger def2-TZVP basis set. Results are as follows: Figure 5 As shown, in the complex, the active site is not Cr(III). H40 in PMS forms hydrogen bonds with O7, O9, O23, or O26 in Cr(III)-EDTA, and after adsorption, the terminal OH bond length in PMS (l O-H )from Increased to It is more easily broken, so the reaction mechanism can be summarized as follows: Compared to free Cr(III), the active site in Cr(III)-EDTA shifts from Cr to the terminal oxygen of EDTA; the complexation of Cr(III) with EDTA avoids the formation of cage-like sulfate radicals that cannot react further with PMS. Through hydrogen bonding with EDTA, electrons are transferred from PMS to the EDTA-Cr(III) ligand, causing PMS to lose hydrogen atoms and promoting its oxidation to SO5. - ·, SO5- ·and then rapidly generate through self-reaction 1 O2.

Claims

1. A method for removing organic pollutants from wastewater using chromium-catalyzed persulfate oxidation, characterized in that, include: Persulfate was added to wastewater containing both chromium and organic pollutants, and the mixture was stirred at room temperature to oxidize and degrade the organic pollutants. Wherein, the chromium is a complexed trivalent chromium, and the organic ligand of the complexed trivalent chromium is ethylenediaminetetraacetic acid ion; The persulfate is potassium peroxymonosulfate; The organic pollutant is one or more of Acid Red 73 dye, p-chlorophenol, tetracycline hydrochloride, and bisphenol A.

2. The method for removing organic pollutants from wastewater by chromium-catalyzed persulfate oxidation according to claim 1, characterized in that, The amount of persulfate added to the wastewater to be treated is 2.5~10 mmol / L.

3. The method for removing organic pollutants from wastewater using chromium-catalyzed persulfate oxidation according to claim 1, characterized in that, The concentration of chromium in the wastewater to be treated is 5~100 mg / L.

4. The method for removing organic pollutants from wastewater by chromium-catalyzed persulfate oxidation according to claim 1, characterized in that, The concentration of organic pollutants in the wastewater to be treated is 10~100 mg / L.

5. The method for removing organic pollutants from wastewater by chromium-catalyzed persulfate oxidation according to claim 1, characterized in that, The pH value of the wastewater to be treated is 3~9.

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