Efficient treatment method for organic wastewater generated based on unsteady-state catalyst circulation

Abstract

The invention discloses an efficient treatment method for organic wastewater generated based on unsteady state catalyst circulation, and belongs to the technical field of wastewater treatment. According to the method, the alkaline precipitant and the acid activator are alternately added, so that transition metal in the wastewater is continuously converted into a high-activity and unsteady-state catalyst which is used for activating an oxidizing agent, and therefore, strong oxidizing species are generated to degrade organic pollutants in the water, the wastewater treatment cost is reduced, and the treatment efficiency is improved. After the unstable catalyst is aged and inactivated, the structure of the unstable catalyst is destroyed through the acid activator, and the unstable catalyst is precipitated again, so that the cyclic generation of the unstable catalyst is realized, and the degradation rate of the pollutants is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and particularly relates to a method for efficiently treating organic wastewater based on the cyclic generation of non-steady catalysts. Background Art

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

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

[0004] CN 117843121 A discloses a method for treating metal organic wastewater. The method is to add an oxidant to the metal organic wastewater, and then add a precipitant and stir or let it stand for reaction; after the solid stands and precipitates, the obtained supernatant is the treated wastewater. The degradation rate of this method is very fast, but the lifespan of some non-steady catalysts is short, and they are quickly inactivated in the organic wastewater system. When the concentration of organic pollutants is high, it is difficult to ensure the complete degradation of organic pollutants, and these undegraded organic pollutants are difficult to efficiently remove subsequently. Summary of the Invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for efficiently treating organic wastewater based on the cyclic generation of non-steady catalysts.

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

[0007] For the above purposes, the present invention provides the following technical solutions:

[0008] A method for efficiently treating organic wastewater based on the cyclic generation of non-steady catalysts, comprising the following steps:

[0009] S1. Adjust the concentration of transition metals in the organic wastewater to 0.01 mmol / L - 2 mol / L; then add an oxidant, and then add a basic precipitant to precipitate the transition metals. The reaction time is 5 min - 600 min. During the reaction process, maintain the pH value of the system at 4.0 - 12.0;

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

[0011] S3. After the precipitate is dissolved, add the basic precipitant again to re-precipitate the transition metals. The reaction time is 5 min - 600 min. During the reaction process, maintain the pH value of the system at 4.0 - 12.0;

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

[0013] In the organic wastewater, the concentration of organic pollutants ≥ 10 μmol / L;

[0014] The transition metal is a transition metal that can form a Fenton-like oxidation system with an oxidant;

[0015] During steps S2 - S3, keep an oxidant in the system, and the concentration of the oxidant in the system ≥ 0.1 μmol / L.

[0016] In the present invention, by alternately adding a basic precipitant and an acidic activator, non-steady catalysts (i.e., precipitates generated by transition metal ions) are continuously generated and dissolved in the organic wastewater. The generated non-steady catalysts can activate the oxidant to produce active oxidation species with strong oxidizing properties. Alternately adding a basic precipitant and an acidic activator can greatly improve the catalytic activity of trace transition metals in the metal organic wastewater and achieve efficient treatment of the organic wastewater. When the non-steady catalyst ages and becomes inactivated, its structure is destroyed by the acidic activator and then precipitated again to realize the cyclic generation of the non-steady catalyst and further improve the degradation rate of pollutants.

[0017] When multiple transition metals are subjected to alkali precipitation in the presence of an oxidant, the generated precipitate has extremely high Fenton-like catalytic activity in a short time. However, as the reaction progresses, the degradation efficiency gradually decreases with the aging of the precipitate. The aged and inactivated precipitate is dissolved by an acidic activator and then alkali precipitation is carried out again to repeatedly generate highly active, non-steady precipitates, enabling rapid degradation of pollutants.

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

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

[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 organic wastewater spontaneously acidifies during the reaction process, resulting in the destruction of the precipitate structure, there is no need to add an acidic activator.

[0022] When the concentration of the oxidant is lower than 0.1 μmol / L during the reaction process of the treatment method of the present invention, it needs to be replenished at any time.

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

[0024] Specifically, the oxidant is at least one of hypochlorous acid, hydrogen peroxide, persulfate, permonosulfate, and peracetic acid.

[0025] Preferably, the oxidant is permonosulfate and / or peracetic acid.

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

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

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

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

[0030] Specifically, the basic precipitant is at least one of soluble hydroxides, soluble carbonates, and soluble bicarbonates.

[0031] More specifically, the basic 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 basic precipitant is 0.1 mol / L to 5 mol / L.

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

[0034] After adding the alkaline precipitant, for the organic wastewater system with a rapid pH change, it is necessary to adjust the pH value 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, until the organic matter concentration drops to 0.1% to 25% of that before treatment.

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

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

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

[0044] (1) The present invention adopts the method of alternately adding an alkaline precipitant and an acidic activator to reactivate the deactivated transition metal precipitate and continuously convert it into a highly active and non-steady catalyst, which is used for the activation of an oxidant, thereby generating strongly oxidizing species to degrade organic pollutants in water, which is beneficial to reducing the treatment cost of wastewater and improving the treatment efficiency.

[0045] (2) The present invention does not require additional preparation of a catalyst and can generate in-situ highly active substances through transition metal ions.

[0046] (3) The present invention has high economic and environmental benefits, is simple and easy to implement, and has a small risk of secondary pollution. Description of the Drawings

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

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

[0049] Figure 3Schematic diagram of the degradation effect of organic pollutants under different oxidants in Examples 1 and 8.

[0050] Figure 4 Schematic diagram of the degradation of 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).

[0051] Figure 5 Schematic diagram of the degradation of organic matter in Example 1 (the pH of the reaction solution is maintained at 9.5 when adding acid and base alternately) and Comparative Example 2 (the pH of the reaction solution is maintained at 3.5 when adding acid and base alternately). Detailed implementation manners

[0052] The present invention will be further described below in conjunction with examples. These examples are only used to illustrate the present invention and not to limit the scope of the present invention. For the experimental methods without specific conditions in the following examples, they are usually carried out according to the conventional conditions in the art or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention fall within the scope claimed by the present invention.

[0053] Example 1

[0054] S1. The 60 mL of organic wastewater to be treated contains 0.5 mmol / L Cu(II) and 1 mmol / L rhodamine B solution, and the initial pH = 3.0. First, add peroxymonosulfate (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 continuously to maintain the pH of the reaction solution at 9.5;

[0055] S2. After reacting for 10 min, the degradation of rhodamine B almost stops, and the degradation rate is about 62% at this time. Supplement 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 regenerate the precipitate of 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% (that is, the concentration of rhodamine B is degraded to 15% of that before treatment);

[0057] S4. After reacting for 8 min by alternately adding acid and base (that is, repeating steps S2 and S3 once), the degradation of rhodamine B is about 99% (such as Figure 1 ).

[0058] Example 2

[0059] S1. The 60 mL of organic wastewater to be treated contains 0.1 mmol / L of Cu(II) and 1 mmol / L of bisphenol A, with an initial pH = 4. First, PMS is added to the organic wastewater to be treated until the concentration of PMS in the system is 1 mmol / L. Subsequently, 0.1 mol / L of 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 then the reaction starts. During the reaction, KOH is added in small amounts and multiple times continuously to maintain the pH of the reaction solution at 9.5;

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

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

[0062] S4. After alternately adding acid and base and reacting for 8 min (that is, repeating steps S2 and S3 once), the degradation rate of bisphenol A is about 85% (as Figure 1 ).

[0063] Example 3

[0064] S1. The 60 mL of organic wastewater to be treated contains 0.1 mmol / L of Cu(II) and 1 mmol / L of tetracycline hydrochloride, with an initial pH = 4. First, PMS is added to the organic wastewater to be treated until the concentration of PMS in the system is 1 mmol / L. Subsequently, 1 mol / L of 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 then the reaction starts. During the reaction, Ca(OH)2 is added in small amounts and multiple times continuously to maintain the pH of the reaction solution at 9.5;

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

[0066] S3. After the precipitation is dissolved, quickly add 1 mol / L Ca(OH)2 to redeposit Cu(II), adjust the pH of the reaction solution to 9.5, and continue the reaction for 10 min. The degradation rate of tetracycline hydrochloride after the reaction is about 81% (i.e., the concentration of tetracycline hydrochloride is degraded to 19% of that before treatment);

[0067] S4. After alternately adding acid and base and reacting for 8 min (i.e., repeating steps S2 and S3 once), the degradation of tetracycline hydrochloride is about 94% (as Figure 1 ).

[0068] Example 4

[0069] S1. The 60 mL of organic wastewater to be treated contains 0.1 mmol / L Cu(II) and 1.5 mmol / L phenol, with an initial pH = 4. First, add PMS to the organic wastewater to be treated until the concentration of PMS in the system is 1 mmol / L. Subsequently, add 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;

[0070] S2. After reacting for 10 min, the degradation of phenol almost stops, and the degradation rate is about 44% at this time. Supplement PMS until the concentration of PMS in the system is 1 mmol / L and add 1 mol / L HCl to dissolve the precipitate;

[0071] S3. After the precipitation is dissolved, quickly add 1 mol / L NaOH to redeposit Cu(II), adjust the pH of the reaction solution to 9.5, and continue the reaction for 10 min. The degradation rate of phenol after the reaction is about 69% (i.e., the concentration of phenol is degraded to 31% of that before treatment);

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

[0073] Example 5

[0074] S1. The 60 mL of organic wastewater to be treated contains 0.5 mmol / L Ni(II) and 1 mmol / L rhodamine B solution, with an initial pH = 3.0. Add PMS to the above water body until the concentration of PMS in the system is 2 mmol / L. Subsequently, add 1 mol / L NaOH under the action of a magnetic stirrer to precipitate Ni(II), maintain the pH of the reaction solution at 9.5 and 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;

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

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

[0077] S4. After reacting by alternately adding acid and base for 8 min (that is, 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 of organic wastewater to be treated contained 0.5 mmol / L Co(II) and 1 mmol / L Rhodamine B solution, and the initial pH = 3.0. PMS was added to the above water body until the concentration of PMS in the system was 2 mmol / L. Subsequently, 1 mol / L NaOH was added under the action of a magnetic stirrer to generate a precipitate of Co(II), and the pH of the reaction solution was maintained at 9.5 and the reaction 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 reacting for 10 min, the degradation of Rhodamine B almost stopped, and the degradation rate was about 56% at this time. 1 mmol / L HCl was added and PMS was replenished until the concentration of PMS in the system was 2 mmol / L to dissolve the precipitate;

[0081] S3. After the precipitate was dissolved, 1 mmol / L NaOH was quickly added to regenerate the precipitate of Co(II), and the pH of the reaction solution was adjusted to 9.5, and the reaction continued for 10 min. The degradation rate of Rhodamine B after the reaction was about 82% (that is, the concentration of Rhodamine B was degraded to 18% of that before treatment);

[0082] S4. After reacting by alternately adding acid and base for 8 min (that is, repeating steps S2 and S3 once), the degradation rate of Rhodamine B was 94% (as Figure 2 ).

[0083] Example 7

[0084] S1. The 60 mL of organic wastewater to be treated contains 0.5 mmol / L of Mn(II) and 1 mmol / L of rhodamine B solution, with an initial pH = 3.0. Add PMS to the above water body until the concentration of PMS in the system is 2 mmol / L, and 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 reacting for 10 min, the degradation of rhodamine B almost stops, and the degradation rate is about 50% at this time. Add 1 mmol / L of HCl and supplement PMS until the concentration of PMS in the system is 2 mmol / L to dissolve the precipitate;

[0086] S3. After the precipitate is dissolved, quickly add 1 mmol / L of NaOH to regenerate the precipitate of Mn(II), and adjust the pH of the reaction solution to 9.5, and continue the reaction for 10 min. The degradation rate of rhodamine B after the reaction is about 70% (that is, the concentration of rhodamine B is degraded to 30% of that before treatment);

[0087] S4. After alternately adding acid and base and reacting for 8 min (that is, repeating steps S2 and S3 once), the degradation rate of rhodamine B is 90% (as Figure 2 ). During the reaction, keep an oxidant in the system.

[0088] Example 8

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

[0090] S2. After reacting for 10 min, the degradation of rhodamine B almost stops, and the degradation rate is about 58% at this time. Add 1 mmol / L of HCl and supplement peracetic acid until the concentration of peracetic acid in the system is 2 mmol / L to dissolve the precipitate;

[0091] S3. After the precipitate is dissolved, quickly add 1 mmol / L of NaOH to regenerate the precipitate of Cu(II), and adjust the pH of the reaction solution to 9.5, and continue the reaction for 10 min. The degradation rate of rhodamine B after the reaction is about 84% (that is, the concentration of rhodamine B is degraded to 16% of that before treatment);

[0092] S4. After alternately adding acid and base and reacting for 8 min (that is, repeating steps S2 and S3 once), the degradation rate of rhodamine B is about 95% (as Figure 3 ).

[0093] Example 10

[0094] S1. The 60 mL of organic wastewater to be treated contains 0.5 mmol / L of Cu(II) and 1 mmol / L of rhodamine B solution, with an initial pH = 3.0. First, add peroxymonosulfate (PMS) to the organic wastewater to be treated until the concentration of PMS in the system is 2 mmol / L. Subsequently, add 1 mmol / L of NaOH under the action of a magnetic stirrer to precipitate Cu(II), and adjust the pH of the reaction solution to 8.5, and then start the reaction. During the reaction, maintain the pH of the reaction solution at 8.5;

[0095] S2. After reacting for 10 min, the degradation of rhodamine B almost stops, and the degradation rate is about 43% at this time. Add 1 mmol / L of HCl and supplement PMS until the concentration of PMS in the system is 2 mmol / L, and the precipitate dissolves;

[0096] S3. Subsequently, quickly add 1 mmol / L of NaOH to regenerate the precipitate of Cu(II), and adjust the pH of the reaction solution to 8.5, and continue to react for 10 min. After the reaction, the degradation of rhodamine B is 70% (that is, the concentration of rhodamine B is degraded to 30% of that before treatment);

[0097] S4. After alternately adding acid and base and reacting for 8 min (that is, repeating steps S2 and S3 once), the degradation of rhodamine B is about 84%.

[0098] Example 11

[0099] S1. The 60 mL of organic wastewater to be treated contains 0.5 mmol / L of Cu(II) and 1 mmol / L of polybrominated diphenyl ether solution, with an initial pH = 3.0. First, add PMS to the organic wastewater to be treated until the concentration of PMS in the system is 2 mmol / L. Subsequently, add 1 mmol / L of 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, maintain the pH of the reaction solution at 9.5;

[0100] S2. After reacting for 10 min, add 1 mmol / L of HCl and supplement PMS until the concentration of PMS in the system is 2 mmol / L, and the precipitate dissolves;

[0101] S3. Subsequently, quickly add 1 mmol / L of NaOH to regenerate the precipitate of 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 polybrominated diphenyl ether is 10% (that is, the concentration of polybrominated diphenyl ether is degraded to 90% of that before treatment);

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

[0103] Example 12

[0104] S1. The 60 mL of organic wastewater to be treated contains 1 mol / L Cu(II) and 1 mol / L rhodamine B solution, with an initial pH = 3.0. First, add peroxymonosulfate (PMS) to the organic wastewater to be treated until the concentration of PMS in the system is 5 mol / L. Subsequently, add 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, maintain the pH of the reaction solution at 9.5;

[0105] S2. After reacting for 10 min, add 1 mol / L HCl and replenish peroxymonosulfate (PMS) until the concentration of PMS in the system is 5 mol / L, and the precipitate dissolves;

[0106] S3. Subsequently, quickly add 1 mol / L NaOH to regenerate the precipitate of Cu(II), and adjust the pH of the reaction solution to 9.5, and continue the reaction for 10 min. After the reaction, the degradation of rhodamine B is 70% (i.e., the concentration of rhodamine B is degraded to 30% of that before treatment);

[0107] S4. After adding acid and base alternately for 8 min (i.e., repeating steps S2 and S3 once), the degradation of rhodamine B is about 99.9%.

[0108] Comparative Example 1

[0109] S1. The 60 mL of organic wastewater to be treated contains 0.1 mmol / L Cu(II) and 0.5 mmol / L rhodamine B solution, with an initial pH = 3.0. First, add peroxymonosulfate (PMS) to the organic wastewater to be treated until the concentration of PMS in the system is 2 mmol / L. Subsequently, add 1 mmol / 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, maintain the pH of the reaction solution at 9.5;

[0110] S2. After reacting for 10 min, add 1 mmol / L HCl, without replenishing peroxymonosulfate (PMS), and the precipitate dissolves;

[0111] S3. Subsequently, quickly add 2 mmol / L NaOH to regenerate the precipitate of Cu(II), and adjust the pH of the reaction solution to 9.5, and continue the reaction for 10 min. After reacting for 10 min, the degradation of rhodamine B is 62% (i.e., the concentration of rhodamine B is degraded to 38% of that before treatment);

[0112] S4. After adding acid and base alternately for 8 min (i.e., repeating steps S2 and S3 once), about 70% of Rhodamine B is degraded (as Figure 4 ).

[0113] Comparative Example 2

[0114] S1. The 60 mL of organic wastewater to be treated contains 0.5 mmol / L Cu(II) and 1 mmol / L Rhodamine B solution, with an initial pH = 3.0. First, peroxymonosulfate (PMS) is added to the organic wastewater to be treated until the concentration of PMS in the system is 2 mmol / L. Subsequently, the pH of the reaction solution is adjusted to 3.5 with 1 mmol / L NaOH under the action of a magnetic stirrer, and then the reaction starts. During the reaction, the pH of the reaction solution is maintained at 3.5;

[0115] S2. After reacting for 10 min, 1 mmol / L HCl is added and peroxymonosulfate (PMS) is replenished until the concentration of PMS in the system is 2 mmol / L, and the precipitate dissolves;

[0116] S3. Subsequently, 0.1 mmol / L NaOH is quickly added to adjust the pH of the reaction solution to 3.5, and the reaction continues for 10 min. After reacting for 10 min, 6% of Rhodamine B is degraded.

[0117] S4. After adding acid and base alternately for 8 min (i.e., repeating steps S2 and S3 once), about 14% of Rhodamine B is degraded (as Figure 5 ).

[0118] During the processes of steps S2 - S3 in Examples 1 - 12 and Comparative Example 2 of the present invention, an oxidant is maintained in the system, and the concentration of the oxidant in the system ≥ 0.1 μmol / L.

[0119] Performance detection

[0120] Detection method for the concentration of organic matter in wastewater:

[0121] 1. Rhodamine B

[0122] The high - performance liquid chromatography method is adopted, and separation is carried out using a C18 column (250 mm × 4.6 mm, 5 μm). The mobile phase is 60% acetonitrile and 40% water, and the flow rate is 1 mL / min. The column temperature is fixed at 20 °C. The injection volume is 10 μL. The absorbance is measured at 554 nm.

[0123] 2. Bisphenol A

[0124] Separation was carried out by high performance liquid chromatography using a C18 column (150 mm × 4.6 mm, 5 μm). The mobile phase was 22% water, 58% methanol, and 20% acetonitrile, and the flow rate was 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 carried out by high performance liquid chromatography using a C18 column (250 mm × 4.6 mm, 5 μm). The mobile phase was 20% methanol, 20% acetonitrile, and 60% of 0.03 mol / L oxalic acid solution, and the flow rate was 1 mL / min. The column temperature was fixed at 25 °C, and the injection volume was 20 μL. The detection wavelength was 351 nm.

[0127] 4. Phenol

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

[0129] Figure 1 is the degradation rate curve graph of the organic substances in Examples 1 to 4; from Figure 1 it can be seen that the organic wastewater treatment method provided by the present invention can be used to degrade different pollutants, and the removal rate ≥ 85% within 30 min after alternately adding acid and alkali.

[0130] Figure 2 is the schematic diagram of the degradation efficiency of organic pollutants under different metal catalysts in Example 1, Examples 5 to 7. From Figure 2 it can be seen that the precipitates generated by alkali precipitation of different transition metals in the presence of an oxidant have extremely high Fenton-like catalytic activity in a short time. After reactivating different metal precipitates, the organic wastewater treatment method provided by the present invention can further rapidly degrade pollutants.

[0131] Figure 3 is the schematic diagram of the degradation effect of organic pollutants under different oxidants in Example 1 and Example 8. It can be seen from the figure that different oxidants are applicable to the wastewater treatment method provided by the present invention.

[0132] Figure 4 is the schematic diagram of the degradation of organic pollutants in Example 1 (adding PMS when alternately adding acid and alkali) and Comparative Example 1 (not adding PMS when alternately adding acid and alkali). It can be seen from the figure that when the oxidant is not supplemented during the treatment of organic wastewater, the degradation efficiency of pollutants cannot be further improved. Therefore, during the treatment of organic wastewater, it is necessary to timely add an oxidant to maintain an appropriate concentration of the oxidant in the system to further improve the degradation efficiency of pollutants.

[0133] Figure 5 Schematic diagram of the degradation of organic pollutants in Example 1 (pH of the reaction solution is 9.5) and Comparative Example 2 (pH of the reaction solution is 3.5). As can be seen from the figure, when the pH of the reaction solution is 3.5, the efficiency of degrading organic pollutants is lower than that when pH = 9.5. Therefore, the reaction solution needs to maintain an appropriate pH value to improve the degradation efficiency of organic pollutants.

[0134] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A highly efficient method for treating organic wastewater based on non-steady-state catalyst cyclic generation, characterized in that: The following steps are involved: S1. Adjust the transition metal concentration in the organic wastewater to 0.01mmol / L~2mol / L; then add an oxidant, and then add an alkaline precipitant to precipitate the transition metal. The reaction time is 5min~600min. During the reaction, the pH value of the system is maintained at 4.0~12.0; S2. After the reaction is completed, an acidic activator is added to dissolve the precipitate; S3. After the precipitate is dissolved, an alkaline precipitant is added again to re-precipitate the transition metal. The reaction time is 5 min to 600 min. During the reaction, the pH value of the system is maintained at 4.0 to 12.0; S4. Repeat steps S2 and S3 until the organic matter concentration drops to 0.1% to 85% of that before treatment; The concentration of organic pollutants in the organic wastewater is ≥10 μmol / L; The transition metal is a transition metal that can form a Fenton-like oxidation system with an oxidant; During steps S2 to S3, the oxidant is maintained in the system, and the concentration of the oxidant in the system is ≥ 0.1 μmol / L.

2. The processing method according to claim 1, characterized in that: The transition metal includes at least one of Cu, Ni, Co, Mn and Fe.

3. The processing method according to claim 1, characterized in that: The organic pollutants in the organic wastewater include at least one of rhodamine B, bisphenol A, tetracycline hydrochloride, phenol, and polybrominated diphenyl ethers.

4. The processing method according to claim 1, characterized in that: The oxidant is at least one of hypochlorous acid, hydrogen peroxide, persulfate, peroxymonosulfate, and peracetic acid.

5. The processing method according to claim 1, characterized in that: The concentration of the oxidant in the system is 0.1 μmol / L to 5 mol / L.

6. The processing method according to claim 1, characterized in that: The alkaline precipitant is at least one of a soluble hydroxide, a soluble carbonate, and a soluble bicarbonate.

7. The processing method according to claim 1, characterized in that: The concentration of the alkaline precipitant is 0.1 mol / L to 5 mol / L.

8. The processing method according to claim 1, characterized in that: The acidic activator is at least one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid and hypochlorous acid.

9. The processing method according to claim 1, characterized in that: The concentration of the acidic activator is 0.1 mol / L to 5 mol / L.

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

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