A high-efficiency treatment method for organic wastewater based on non-steady-state catalyst circulation generation

Abstract

The application discloses a kind of based on unsteady catalyst cyclic generation organic wastewater efficient treatment method, belong to wastewater treatment technical field.The application uses the method of alternately adding alkaline precipitant and acidic activator, continuously converts transition metal in wastewater into high-activity, unsteady catalyst, and is used for the activation of oxidizing agent, so as to produce strong oxidizing species degradation organic pollutants in water, it is favorable to reduce the treatment cost of wastewater and improve processing efficiency.When unsteady catalyst is deactivated after aging, its structure is destroyed by acidic activator and precipitated again, realizing the cyclic generation of unsteady catalyst, further improving the degradation rate of pollutants.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a high-efficiency treatment method for organic wastewater based on cyclic generation of non-steady-state catalysts. BACKGROUND

[0002] With the vigorous development of China's industry, a large amount of difficult-to-degrade organic wastewater with complex components and poor biodegradability is generated, and it is difficult to achieve ideal treatment effect by using conventional water treatment methods. The advanced oxidation technology has been widely applied in the treatment of such difficult-to-degrade wastewater. The oxidation active species generated by the technology has strong oxidizing property and can oxidize the difficult-to-degrade organic pollutants in the wastewater into small molecular compounds with low toxicity or no toxicity, thereby enhancing the biodegradability of the wastewater. The Fenton-like oxidation technology is one of the most common advanced oxidation technologies. The technology uses catalysts to activate oxidants, thereby generating oxidation active species to degrade pollutants. The technology has the advantages of high efficiency and simple operation, and is one of the focuses in the field of water treatment.

[0003] Although a large number of Fenton-like oxidation systems have been reported at present, especially various catalysts. Among the existing catalysts, the catalysts composed of non-steady-state phases can exhibit extremely high catalytic activity and achieve high-speed degradation of pollutants. However, such catalysts are unstable in nature, and during use, they are prone to phase transformation due to their own aging and interaction with pollutants, which makes it difficult to maintain the treatment efficiency for a long time, which is an important factor limiting their application.

[0004] CN 117843121 A discloses a treatment method for metal organic wastewater. The method comprises adding an oxidizing agent to the metal organic wastewater, then adding a precipitating agent and stirring or standing for reaction. After the solid is allowed to stand and precipitate, the supernatant obtained is the treated wastewater. The method has a very fast degradation rate, but part of the non-steady-state catalysts have a short service life and are quickly deactivated in the organic wastewater system. When the concentration of organic pollutants is high, it is difficult to ensure complete degradation of the organic pollutants, and these undegraded organic pollutants are difficult to be removed efficiently subsequently. SUMMARY

[0005] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a high-efficiency treatment method for organic wastewater based on cyclic generation of non-steady-state catalysts.

[0006] Another purpose of the present application is to provide the application of the above method in the treatment of organic wastewater.

[0007] In order to achieve the above purpose, the present application provides the following technical solutions:

[0008] A high-efficiency treatment method for organic wastewater based on cyclic generation of non-steady-state catalysts, comprising the following steps:

[0009] S1. Adjusting the concentration of transition metal in the organic wastewater to 0.01 mmol / L-2 mol / L; then adding an oxidizing agent, and then adding an alkaline precipitant to make the transition metal precipitate, the reaction time being 5 min-600 min, and the pH value of the system being maintained at 4.0-12.0 during the reaction;

[0010] S2. After the reaction is completed, an acid activator is added to dissolve the precipitate;

[0011] S3. After the precipitate is dissolved, an alkaline precipitant is added again to make the transition metal re-precipitate, the reaction time being 5 min-600 min, and the pH value of the system being maintained at 4.0-12.0 during the reaction;

[0012] S4. Repeating steps S2 and S3 until the concentration of organic matter is reduced to 0.1%-85% of that before the treatment;

[0013] The concentration of the organic pollutants in the organic wastewater is ≥10 μmol / L;

[0014] The transition metal is a transition metal capable of forming a Fenton-like oxidation system with the oxidizing agent;

[0015] During steps S2-S3, the oxidizing agent is kept in the system, and the concentration of the oxidizing agent in the system is ≥0.1 μmol / L.

[0016] The application can greatly improve the catalytic activity of trace transition metals in metal-organic wastewater by alternately adding alkaline precipitants and acid activators to make the non-stable catalyst (i.e. the precipitate of transition metal ions) in the organic wastewater continuously generate and dissolve, wherein the generated non-stable catalyst can activate the oxidizing agent to produce active oxidizing species with strong oxidizing property. The alternately adding alkaline precipitants and acid activators can greatly improve the catalytic activity of trace transition metals in metal-organic wastewater, and realize efficient treatment of the organic wastewater. When the non-stable catalyst is aged and deactivated, its structure is destroyed by the acid activator and re-precipitates, realizing the cyclic generation of the non-stable catalyst and further improving the degradation rate of pollutants.

[0017] A plurality of transition metals are subjected to alkaline precipitation in the presence of an oxidizing agent, and the generated precipitate has extremely high Fenton-like catalytic activity in a short time. However, as the reaction proceeds, the degradation efficiency gradually decreases with the aging of the precipitate. The acid activator is used to dissolve the aged and deactivated precipitate, and alkaline precipitation is performed again to repeatedly generate high-activity non-stable precipitate, so that the pollutants are rapidly degraded.

[0018] Specifically, the transition metal includes at least one of Cu, Ni, Co, Mn and Fe.

[0019] For the organic wastewater without transition metal ions or with insufficient concentration of transition metal ions, the concentration of transition metal ions can be adjusted by adding additional transition metal ions to keep the concentration of transition metal ions in the required concentration range.

[0020] Preferably, the concentration of transition metal ions in the organic wastewater is 0.02 mmol / L to 1 mol / L.

[0021] For step S2, if the structure of the precipitate is destroyed due to spontaneous acidification of the organic wastewater during the reaction, no acid activator needs to be added.

[0022] The treatment method of the present application needs to be supplemented in time when the concentration of the oxidizing agent is lower than 0.1 μmol / L during the reaction.

[0023] Specifically, the organic pollutants in the organic wastewater include at least one of rhodamine B, bisphenol A, tetracycline hydrochloride, phenol, and polybrominated diphenyl ether.

[0024] Specifically, the oxidizing agent is at least one of hypochlorous acid, hydrogen peroxide, persulfate, peroxymonosulfate, and peroxyacetic acid.

[0025] Preferably, the oxidizing agent is peroxymonosulfate and / or peroxyacetic acid.

[0026] Preferably, the concentration of the organic pollutants in the organic wastewater is ≥1 mmol / L.

[0027] Specifically, the concentration of the oxidizing agent in the system is 0.1 μmol / L to 5 mol / L.

[0028] Preferably, the concentration of the oxidizing agent in the system is 1 μmol / L to 5 mol / L.

[0029] Preferably, the molar concentration ratio of the organic pollutants to the oxidizing agent in the system is (1-2):(1-10).

[0030] Specifically, the alkaline precipitant is at least one of soluble hydroxide, soluble carbonate, and soluble bicarbonate.

[0031] More specifically, the alkaline precipitant is at least one of sodium hydroxide, magnesium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, and sodium bicarbonate.

[0032] Specifically, the concentration of the alkaline precipitant is 0.1 mol / L to 5 mol / L.

[0033] Preferably, the concentration of the alkaline precipitant is 0.1 mol / L to 1 mol / L.

[0034] For the organic wastewater system with fast pH change after adding the basic precipitant, the pH value needs to be adjusted to further improve the catalytic performance of the precipitate.

[0035] Preferably, in step S1, the reaction time is 5 min to 30 min.

[0036] Specifically, the acidic activator is at least one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and hypochlorous acid.

[0037] Specifically, the concentration of the acidic activator is 0.1 mol / L to 5 mol / L.

[0038] Preferably, the concentration of the acidic activator is 0.5 mol / L to 2 mol / L.

[0039] Preferably, in step S3, the reaction time is 5 min to 30 min.

[0040] Preferably, in step S4, the concentration of the organic matter is reduced to 0.1% to 25% of the concentration before treatment.

[0041] More preferably, in step S4, the concentration of the organic matter is reduced to 1% to 21% of the concentration before treatment.

[0042] The application also protects the use of the above treatment method in treating organic wastewater.

[0043] Compared with the prior art, the application has the following technical effects:

[0044] (1) The application uses the method of alternately adding a basic precipitant and an acidic activator to re-activate the deactivated transition metal precipitate and continuously convert it into a high-activity, non-steady-state catalyst, which is used for the activation of an oxidizing agent, thereby generating a strong oxidizing species to degrade organic pollutants in water, which is conducive to reducing the treatment cost of wastewater and improving the treatment efficiency.

[0045] (2) The application does not need to prepare a catalyst additionally, and can generate in-situ high-activity substances through transition metal ions.

[0046] (3) The application has high economic and environmental benefits, is simple and easy to implement, and has low risk of secondary pollution. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 The figure is a schematic diagram of the degradation efficiency of organic pollutants in Examples 1 to 4.

[0048] Figure 2 The figure is a schematic diagram of the degradation efficiency of organic pollutants under different metal catalysts in Examples 1, 5 to 7.

[0049] Figure 3The organic pollutant degradation effect diagram under different oxidants in Examples 1 and 8.

[0050] Figure 4 The organic pollutant degradation diagram in Example 1 (PMS is supplemented when acid and base are alternately added) and Comparative Example 1 (PMS is not supplemented when acid and base are alternately added).

[0051] Figure 5 The organic pollutant degradation diagram in Example 1 (the pH of the reaction solution is maintained at 9.5 when acid and base are alternately added) and Comparative Example 2 (the pH of the reaction solution is maintained at 3.5 when acid and base are alternately added). DETAILED DESCRIPTION

[0052] The application will be further described in conjunction with the examples. The examples are only used to illustrate the application and are not used to limit the scope of the application. The experimental methods in the following example are not specified, and are generally carried out according to the conventional conditions in the art or according to the conditions recommended by the manufacturers; the raw materials, reagents, etc. used, if not specifically stated, are commercially available raw materials and reagents. Any non-essential changes and substitutions made by those skilled in the art on the basis of the application all fall within the scope of the application.

[0053] Example 1

[0054] S1. The 60 mL organic wastewater to be treated contains 0.5 mmol / L Cu(II) and 1 mmol / L rhodamine B solution, and the initial pH is 3.0. First, add persulfate (PMS) to the organic wastewater to be treated until the concentration of PMS in the system is 2 mmol / L, then add 0.1 mol / L NaOH under the action of a magnetic stirrer to precipitate Cu(II), and adjust the pH of the reaction solution to 9.5, and then start the reaction. During the reaction, add NaOH in small amounts and multiple times to maintain the pH of the reaction solution at 9.5;

[0055] S2. After 10 min of reaction, the degradation of rhodamine B almost stops, at which time the degradation rate is about 62%. Add PMS until the concentration of PMS in the system is 2 mmol / L and add 1 mol / L HCl to dissolve the precipitate;

[0056] S3. After the precipitate is dissolved, quickly add 0.5 mol / L NaOH to re-precipitate Cu(II), and adjust the pH of the reaction solution to 9.5, and continue to react for 10 min. After the reaction, the degradation of rhodamine B is 85% (i.e. the concentration of rhodamine B is degraded to 15% of that before treatment);

[0057] S4. After 8 min of reaction by alternately adding acid and base (i.e. repeating steps S2 and S3 once), the degradation of rhodamine B is about 99% (as shown in Figure 1 ).

[0058] Example 2

[0059] S1. The 60 mL organic wastewater to be treated contains 0.1 mmol / L Cu(II) and 1 mmol / L bisphenol A, and the initial pH is 4. First, PMS is added to the organic wastewater to be treated until the concentration of PMS in the system is 1 mmol / L, then 0.1 mol / L KOH is added under the action of a magnetic stirrer to precipitate Cu(II), and the pH of the reaction solution is adjusted to 9.5, and the reaction is started immediately. KOH is added continuously in small amounts during the reaction to maintain the pH of the reaction solution at 9.5;

[0060] S2. After 10 min of reaction, the degradation of bisphenol A almost stops, at which time the degradation rate is about 45%. PMS is supplemented until the concentration of PMS in the system is 1 mmol / L, and 1 mol / L HCl is added to dissolve the precipitate;

[0061] S3. After the precipitate is dissolved, 1 mol / L KOH is quickly added to re-precipitate Cu(II), and the pH of the reaction solution is adjusted to 9.5, and the reaction is continued for 10 min. After the reaction, the degradation rate of bisphenol A is 68% (i.e., the concentration of bisphenol A is degraded to 32% of the pre-treatment);

[0062] S4. After 8 min of alternating addition of acid and base (i.e., repeating steps S2 and S3 once), the degradation rate of bisphenol A is about 85% (e.g. Figure 1 ).

[0063] Example 3

[0064] S1. The 60 mL organic wastewater to be treated contains 0.1 mmol / L Cu(II) and 1 mmol / L tetracycline hydrochloride, and the initial pH is 4. First, PMS is added to the organic wastewater to be treated until the concentration of PMS in the system is 1 mmol / L, then 1 mol / L Ca(OH)2 is added under the action of a magnetic stirrer to precipitate Cu(II), and the pH of the reaction solution is adjusted to 9.5, and the reaction is started immediately. Ca(OH)2 is added continuously in small amounts during the reaction to maintain the pH of the reaction solution at 9.5;

[0065] S2. After 10 min of reaction, the degradation of tetracycline hydrochloride almost stops, at which time the degradation rate is about 51%. PMS is supplemented until the concentration of PMS in the system is 1 mmol / L, and 1 mol / L HCl is added to dissolve the precipitate;

[0066] S3. After the precipitation was dissolved, 1 mol / L Ca(OH)2 was quickly added to make Cu(II) re-precipitate, and the pH of the reaction solution was adjusted to 9.5, and the reaction was continued for 10 min. After the reaction, the degradation rate of tetracycline hydrochloride was about 81% (i.e., the concentration of tetracycline hydrochloride was degraded to 19% of that before treatment);

[0067] S4. After the reaction of 8 min by alternately adding acid and base (i.e., repeating steps S2 and S3 once), the degradation rate of tetracycline hydrochloride was about 94% (e.g. Figure 1 ).

[0068] Example 4

[0069] S1. The 60 mL organic wastewater to be treated contained 0.1 mmol / L Cu(II) and 1.5 mmol / L phenol, and the initial pH was 4. PMS was first added to the organic wastewater to be treated until the concentration of PMS in the system was 1 mmol / L, and then 1 mol / L NaOH was added under the action of a magnetic stirrer to make Cu(II) precipitate, and the pH of the reaction solution was adjusted to 9.5, and the reaction was started immediately. NaOH was added in small amounts and multiple times during the reaction to maintain the pH of the reaction solution at 9.5;

[0070] S2. After 10 min of reaction, the degradation of phenol almost stopped, and at this time the degradation rate was about 44%. PMS was supplemented until the concentration of PMS in the system was 1 mmol / L, and 1 mol / L HCl was added to dissolve the precipitate;

[0071] S3. After the precipitation was dissolved, 1 mol / L NaOH was quickly added to make Cu(II) re-precipitate, and the pH of the reaction solution was adjusted to 9.5, and the reaction was continued for 10 min. After the reaction, the degradation rate of phenol was about 69% (i.e., the concentration of phenol was degraded to 31% of that before treatment);

[0072] S4. After the reaction of 8 min by alternately adding acid and base (i.e., repeating steps S2 and S3 once), the degradation rate of phenol was about 87% (e.g. Figure 1 ).

[0073] Example 5

[0074] S1. The 60 mL organic wastewater to be treated contained 0.5 mmol / L Ni(II) and 1 mmol / L rhodamine B solution, and the initial pH was 3.0. PMS was added to the above water body until the concentration of PMS in the system was 2 mmol / L, and then 1 mol / L NaOH was added under the action of a magnetic stirrer to make Ni(II) precipitate, and the pH of the reaction solution was maintained at 9.5 and the reaction was started. NaOH was added in small amounts and multiple times during the reaction to maintain the pH of the reaction solution at 9.5;

[0075] S2. After 10 min of reaction, the degradation of Rhodamine B almost stopped, at this time the degradation rate was about 55%, 1 mmol / L HCl was added and PMS was supplemented until the concentration of PMS in the system was 2 mmol / L, and the precipitate was dissolved;

[0076] S3. After the precipitate was dissolved, 1 mmol / L NaOH was quickly added to make Ni(II) re-precipitate, and the pH of the reaction solution was adjusted to 9.5, and the reaction was continued for 10 min. After the reaction, the degradation rate of Rhodamine B was about 72% (i.e. the concentration of Rhodamine B was degraded to 28% of that before treatment);

[0077] S4. After 8 min of alternate addition of acid and base (i.e. repeating steps S2 and S3 once), the degradation rate of Rhodamine B was about 91% (as Figure 2 ).

[0078] Example 6

[0079] S1. The 60 mL organic wastewater to be treated contained 0.5 mmol / L Co(II) and 1 mmol / L Rhodamine B solution, and the initial pH was 3.0. PMS was added to the above water body until the concentration of PMS in the system was 2 mmol / L, then 1 mol / L NaOH was added under the action of a magnetic stirrer to make Co(II) precipitate, and the pH of the reaction solution was maintained at 9.5 and the reaction was started. During the reaction, NaOH was added in small amounts and multiple times to maintain the pH of the reaction solution at 9.5;

[0080] S2. After 10 min of reaction, the degradation of Rhodamine B almost stopped, at this time the degradation rate was about 55%, 1 mmol / L HCl was added and PMS was supplemented until the concentration of PMS in the system was 2 mmol / L, and the precipitate was dissolved;

[0081] S3. After the precipitate was dissolved, 1 mmol / L NaOH was quickly added to make Co(II) re-precipitate, and the pH of the reaction solution was adjusted to 9.5, and the reaction was continued for 10 min. After the reaction, the degradation rate of Rhodamine B was about 72% (i.e. the concentration of Rhodamine B was degraded to 28% of that before treatment);

[0082] S4. After 8 min of alternate addition of acid and base (i.e. repeating steps S2 and S3 once), the degradation rate of Rhodamine B was about 91% (as Figure 2 ).

[0083] Example 7

[0084] S1. The 60 mL organic wastewater to be treated contains 0.5 mmol / L Mn(II) and 1 mmol / L rhodamine B solution, and the initial pH is 3.0. Add PMS to the above water body until the concentration of PMS in the system is 2 mmol / L, then add 1 mol / L NaOH under the action of a magnetic stirrer to precipitate Mn(II), and maintain the pH of the reaction solution at 9.5 and start the reaction;

[0085] S2. After 10 min of reaction, the degradation of rhodamine B almost stops, at which time the degradation rate is about 50%, 1 mmol / L HCl is added and PMS is supplemented until the concentration of PMS in the system is 2 mmol / L, and the precipitate is dissolved;

[0086] S3. After the precipitate is dissolved, 1 mmol / L NaOH is quickly added to re-precipitate Mn(II), and the pH of the reaction solution is adjusted to 9.5, and the reaction is continued for 10 min. After the reaction, the degradation rate of rhodamine B is about 70% (i.e. the concentration of rhodamine B is degraded to 30% of that before treatment);

[0087] S4. After 8 min of alternate addition of acid and base (i.e. repeating steps S2 and S3 once), the degradation rate of rhodamine B is 90% (e.g. Figure 2 ). During the reaction, an oxidizing agent is maintained in the system.

[0088] Example 8

[0089] S1. The 60 mL organic wastewater to be treated contains 0.5 mmol / L Cu(II) and 1 mmol / L rhodamine B solution, and the initial pH is 3.0. Add peracetic acid to the above water body until the concentration of peracetic acid in the system is 2 mmol / L, then add 1 mol / L NaOH under the action of a magnetic stirrer to precipitate Cu(II), and maintain the pH of the reaction solution at 9.5 and start the reaction;

[0090] S2. After 10 min of reaction, the degradation of rhodamine B almost stops, at which time the degradation rate is about 58%, 1 mmol / L HCl is added and peracetic acid is supplemented until the concentration of peracetic acid in the system is 2 mmol / L, and the precipitate is dissolved;

[0091] S3. After the precipitate is dissolved, 1 mmol / L NaOH is quickly added to re-precipitate Cu(II), and the pH of the reaction solution is adjusted to 9.5, and the reaction is continued for 10 min. After the reaction, the degradation rate of rhodamine B is about 84% (i.e. the concentration of rhodamine B is degraded to 16% of that before treatment);

[0092] S4. After 8 min of alternate addition of acid and base (i.e. repeating steps S2 and S3 once), the degradation rate of rhodamine B is about 95% (e.g. Figure 3 ).

[0093] Example 10

[0094] S1. The 60 mL organic wastewater to be treated contained 0.5 mmol / L Cu(II) and 1 mmol / L rhodamine B solution, and the initial pH was 3.0. First, PMS was added to the organic wastewater to be treated until the concentration of PMS in the system was 2 mmol / L, then 1 mmol / L NaOH was added under the action of a magnetic stirrer to precipitate Cu(II), and the pH of the reaction solution was adjusted to 8.5, and the reaction was started immediately. During the reaction, the pH of the reaction solution was maintained at 8.5;

[0095] S2. After 10 min of reaction, the degradation of rhodamine B almost stopped, at which time the degradation rate was about 43%, 1 mmol / L HCl was added and PMS was supplemented until the concentration of PMS in the system was 2 mmol / L, and the precipitate was dissolved;

[0096] S3. Then 1 mmol / L NaOH was quickly added to re-precipitate Cu(II), and the pH of the reaction solution was adjusted to 8.5, and the reaction was continued for 10 min. After the reaction, rhodamine B was degraded by 70% (i.e. the concentration of rhodamine B was degraded to 30% of that before treatment);

[0097] S4. After 8 min of alternating addition of acid and base (i.e. repeating steps S2 and S3 once), rhodamine B was degraded by about 84%.

[0098] Example 11

[0099] S1. The 60 mL organic wastewater to be treated contained 0.5 mmol / L Cu(II) and 1 mmol / L polybrominated diphenyl ether solution, and the initial pH was 3.0. First, PMS was added to the organic wastewater to be treated until the concentration of PMS in the system was 2 mmol / L, then 1 mmol / L NaOH was added under the action of a magnetic stirrer to precipitate Cu(II), and the pH of the reaction solution was adjusted to 9.5, and the reaction was started immediately. During the reaction, the pH of the reaction solution was maintained at 9.5;

[0100] S2. After 10 min of reaction, 1 mmol / L HCl was added and PMS was supplemented until the concentration of PMS in the system was 2 mmol / L, and the precipitate was dissolved;

[0101] S3. Then 1 mmol / L NaOH was quickly added to re-precipitate Cu(II), and the pH of the reaction solution was adjusted to 9.5, and the reaction was continued for 10 min. After the reaction, polybrominated diphenyl ether was degraded by 10% (i.e. the concentration of polybrominated diphenyl ether was degraded to 90% of that before treatment);

[0102] S4. After 600 min of reaction by alternately adding acid and base (i.e. repeating steps S2 and S3 ten times), the degradation of polybrominated diphenyl ethers was about 79%.

[0103] Example 12

[0104] S1. The 60 mL organic wastewater to be treated contained 1 mol / L Cu(II) and 1 mol / L rhodamine B solution, and the initial pH was 3.0. First, peroxymonosulfate (PMS) was added to the organic wastewater to be treated until the concentration of PMS in the system was 5 mol / L, then 1 mol / L NaOH was added under the action of a magnetic stirrer to precipitate Cu(II), and the pH of the reaction solution was adjusted to 9.5, and the reaction was started immediately. During the reaction, the pH of the reaction solution was maintained at 9.5;

[0105] S2. After 10 min of reaction, 1 mol / L HCl was added and peroxymonosulfate (PMS) was added to dissolve the precipitate;

[0106] S3. Then 1 mol / L NaOH was quickly added to re-precipitate Cu(II), and the pH of the reaction solution was adjusted to 9.5, and the reaction was continued for 10 min. After the reaction, rhodamine B was degraded by 70% (i.e. the concentration of rhodamine B was degraded to 30% of that before treatment);

[0107] S4. After 8 min of reaction by alternately adding acid and base (i.e. repeating steps S2 and S3 once), rhodamine B was degraded by about 99.9%.

[0108] Comparative Example 1

[0109] S1. The 60 mL organic wastewater to be treated contained 0.1 mmol / L Cu(II) and 0.5 mmol / L rhodamine B solution, and the initial pH was 3.0. First, peroxymonosulfate (PMS) was added to the organic wastewater to be treated until the concentration of PMS in the system was 2 mmol / L, then 1 mmol / L NaOH was added under the action of a magnetic stirrer to precipitate Cu(II), and the pH of the reaction solution was adjusted to 9.5, and the reaction was started immediately. During the reaction, the pH of the reaction solution was maintained at 9.5;

[0110] S2. After 10 min of reaction, 1 mmol / L HCl was added, and no peroxymonosulfate (PMS) was added to dissolve the precipitate;

[0111] S3. Then 2 mmol / L NaOH was quickly added to re-precipitate Cu(II), and the pH of the reaction solution was adjusted to 9.5, and the reaction was continued for 10 min. After 10 min of reaction, rhodamine B was degraded by 62% (i.e. the concentration of rhodamine B was degraded to 38% of that before treatment);

[0112] S4. After 8 min of alternate addition of acid and base (i.e. repeating steps S2 and S3 once), about 70% of rhodamine B was degraded (as shown in Figure 4 ).

[0113] Comparative Example 2

[0114] S1. The 60 mL organic wastewater to be treated contained 0.5 mmol / L Cu(II) and 1 mmol / L rhodamine B solution, and the initial pH was 3.0. First, persulfate (PMS) was added to the organic wastewater to be treated until the concentration of PMS in the system was 2 mmol / L, and then the pH of the reaction solution was adjusted to 3.5 using 1 mmol / L NaOH under the action of a magnetic stirrer, and the reaction was immediately started. During the reaction, the pH of the reaction solution was maintained at 3.5.

[0115] S2. After 10 min, 1 mmol / L HCl was added and persulfate (PMS) was added to the system until the concentration of PMS in the system was 2 mmol / L, and the precipitate was dissolved.

[0116] S3. Then 0.1 mmol / L NaOH was quickly added to adjust the pH of the reaction solution to 3.5, and the reaction was continued for 10 min. After 10 min of reaction, 6% of rhodamine B was degraded.

[0117] S4. After 8 min of alternate addition of acid and base (i.e. repeating steps S2 and S3 once), about 70% of rhodamine B was degraded (as shown in Figure 5 ).

[0118] During steps S2-S3 of Examples 1-12 and Comparative Example 2 of the present application, an oxidizing agent was maintained in the system, and the concentration of the oxidizing agent in the system was ≥0.1 μmol / L.

[0119] Performance detection

[0120] Method for detecting the concentration of organic matter in wastewater:

[0121] 1. Rhodamine B

[0122] High performance liquid chromatography was used for separation using a C18 column (250 mm x 4.6 mm, 5 μm). The mobile phase was 60% acetonitrile and 40% water, and the flow rate was 1 mL / min. The column temperature was fixed at 20°C. The injection volume was 10 μL. The absorbance was measured at 554 nm.

[0123] 2. Bisphenol A

[0124] Separation was performed using a C18 column (150 mm x 4.6 mm, 5 μm) by high performance liquid chromatography. The mobile phase was 22% water, 58% methanol, 20% acetonitrile at a flow rate of 0.66 mL / min. The column temperature was fixed at 35 °C. The injection volume was 20 μL. The detection wavelength was 224 nm.

[0125] 3. Tetracycline hydrochloride

[0126] Separation was performed using a C18 column (250 mm x 4.6 mm, 5 μm) by high performance liquid chromatography. The mobile phase was 20% methanol, 20% acetonitrile, 60% 0.03 mol / L oxalic acid solution at a flow rate of 1 mL / min. The column temperature was fixed at 25 °C. The injection volume was 20 μL. The detection wavelength was 351 nm.

[0127] 4. Phenol

[0128] Separation was performed using a C18 column (250 mm x 4.6 mm, 5 μm) by high performance liquid chromatography. The mobile phase was 80% methanol and 20% water at a flow rate of 1 mL / min. The column temperature was fixed at 45 °C. The injection volume was 10 μL. The detection wavelength was 280 nm.

[0129] Figure 1 is a degradation rate curve of the organic matter in Examples 1-4. As can be seen from Figure 1 , the organic wastewater treatment method provided by the present application can be used to degrade different pollutants, and the removal rate is ≥ 85% within 30 min after the alternate addition of acid and base.

[0130] Figure 2 is a degradation efficiency diagram of the organic pollutants under different metal catalysts in Example 1, Examples 5-7. As can be seen from Figure 2 , the precipitate produced by the alkali precipitation of different transition metals in the presence of an oxidant has extremely high Fenton-like catalytic activity in a short time. The organic wastewater treatment method provided by the present application can further rapidly degrade the pollutants after the reactivation of the different metal precipitates.

[0131] Figure 3 is a degradation effect diagram of the organic pollutants under different oxidants in Example 1 and Example 8. As can be seen from the diagram, different oxidants can be suitable for the wastewater treatment method provided by the present application.

[0132] Figure 4 is a degradation diagram of the organic pollutants in Example 1 (supplementing PMS when adding acid and base alternately) and Comparative Example 1 (not supplementing PMS when adding acid and base alternately). As can be seen from the diagram, when no oxidant is supplemented during the organic wastewater treatment process, the degradation efficiency of the pollutants cannot be further improved. Therefore, during the organic wastewater treatment process, the oxidant needs to be supplemented in time to maintain a suitable concentration of the oxidant in the system, so as to further improve the degradation efficiency of the pollutants.

[0133] Figure 5 The degradation of organic pollutants for Example 1 (pH of the reaction solution is 9.5) and Comparative Example 2 (pH of the reaction solution is 3.5) is shown in the figure. As can be seen from the figure, the degradation efficiency of the organic pollutants at pH 3.5 is lower than that at pH 9.5. Therefore, the reaction solution needs to be kept at a suitable pH to improve the degradation efficiency of the organic pollutants.

[0134] Obviously, the above-mentioned embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and also impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method for efficient treatment of organic wastewater based on non-steady-state catalyst circulation generation, characterized by, The method comprises the following steps: S1. Adjusting the concentration of transition metal in the organic wastewater to 0.01 mmol / L-2 mol / L; then adding an oxidant, and then adding an alkaline precipitant to make the transition metal precipitate, and the reaction time is 5 min-600 min, and the pH value of the system is maintained at 4.0-12.0 during the reaction; S2. After the reaction is completed, an acid activator is added to dissolve the precipitate; S3. After the precipitate is dissolved, an alkaline precipitant is added again to make the transition metal re-precipitate, and the reaction time is 5 min-600 min, and the pH value of the system is maintained at 4.0-12.0 during the reaction; S4. Steps S2 and S3 are repeated until the concentration of the organic matter is reduced to 0.1%-85% of that before the treatment; The concentration of the organic pollutants in the organic wastewater is ≥10 μmol / L; The transition metal is a transition metal capable of forming a Fenton-like oxidation system with the oxidant; During steps S2-S3, the oxidant is kept in the system, and the concentration of the oxidant in the system is ≥0.1 μmol / L.

2. The process according to claim 1, characterized in that, The transition metal comprises at least one of Cu, Ni, Co, Mn and Fe.

3. The method of claim 1, wherein, The organic pollutants in the organic wastewater comprise at least one of rhodamine B, bisphenol A, tetracycline hydrochloride, phenol and polybrominated diphenyl ether.

4. The process of claim 1 wherein, The oxidant is at least one of hypochlorous acid, hydrogen peroxide, persulfate, peroxymonosulfate and peroxyacetic acid.

5. The method of claim 1 wherein, The concentration of the oxidant in the system is 0.1 μmol / L-5 mol / L.

6. The process of claim 1 wherein, The alkaline precipitant is at least one of soluble hydroxide, soluble carbonate and soluble bicarbonate.

7. The method of claim 1 wherein, The concentration of the alkaline precipitant is 0.1 mol / L-5 mol / L.

8. The process of claim 1 wherein, The acid activator is at least one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid and hypochlorous acid.

9. The method of claim 1 wherein, The concentration of the acid activator is 0.1 mol / L-5 mol / L.

10. The use of the treatment method according to any one of claims 1-9 in treating organic wastewater.

Images