High-temperature Fenton-like oxidation method for industrial wastewater treatment

Abstract

The invention discloses a high-temperature Fenton-like oxidation method for industrial wastewater treatment, and relates to the technical field of wastewater treatment.The high-temperature Fenton-like oxidation method specifically comprises the steps that industrial wastewater is pretreated, and solid particles and suspended solids in the industrial wastewater are removed; heating the pretreated industrial wastewater to 60-90 DEG C, then adding copper sulfate and a hydrogen peroxide solution, adjusting the pH value to 3-7, and stirring to react for 1-4 hours; after the reaction is finished, adjusting the pH value to 9-11, filtering the reaction liquid, collecting copper sludge, adding a sulfuric acid solution into the copper sludge, uniformly mixing, and then filtering and collecting filtrate to obtain a recycled copper sulfate solution; meanwhile, neutralizing, settling and refiltering the wastewater after filtering the reaction liquid to remove the copper sludge, detecting the chemical oxygen demand of the wastewater, and discharging or carrying out secondary treatment after the chemical oxygen demand reaches the discharge standard; the copper sulfate serving as a catalyst has excellent performance under a high-temperature condition, the oxidation efficiency is improved, the application range is expanded, and the copper sulfate is applied to a Fenton-like oxidation process, so that the oxidation rate of hydrogen peroxide can be increased, and the Fenton oxidation effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a high-temperature Fenton-like oxidation method for industrial wastewater treatment. Background Art

[0002] Wastewater discharged during industrial production, especially wastewater containing organic pollutants, such as wastewater from the chemical, pharmaceutical, printing and dyeing industries, is characterized by high concentration and difficulty in degradation. Traditional physical, chemical and biological methods are often difficult to effectively treat such wastewater.

[0003] As an advanced oxidation technology, Fenton oxidation has shown good results in treating difficult-to-degrade organic pollutants. Its principle is to use hydrogen peroxide to produce highly oxidizing hydroxyl radicals (·OH) under the action of divalent iron to degrade organic pollutants in wastewater, but its application still faces the following problems:

[0004] 1. The stability of iron ions: Iron ions are prone to precipitation, especially when there are high concentrations of phosphates, carbonates, etc. in wastewater, which can easily form insoluble iron compounds and reduce the reaction rate;

[0005] 2. High pH value requirements: usually need to operate under acidic conditions of pH 2-4;

[0006] 3. Catalyst consumption: The iron-based catalyst used in the Fenton reaction will produce secondary pollutants such as iron hydroxide, causing secondary pollution and increasing treatment costs.

[0007] Therefore, it is of great practical significance to develop a high-temperature Fenton-like oxidation method and achieve efficient recycling of the catalyst. Summary of the invention

[0008] The object of the present invention is to provide a high-temperature Fenton-like oxidation method for industrial wastewater treatment to solve the following technical problems:

[0009] How to improve reaction efficiency and achieve efficient catalyst recycling in high-temperature Fenton-like oxidation methods.

[0010] The purpose of the present invention can be achieved through the following technical solutions:

[0011] The present invention discloses a high-temperature Fenton-like oxidation method for industrial wastewater treatment, comprising the following steps:

[0012] Step 1: pre-treat industrial wastewater to remove solid particles and suspended matter;

[0013] Step 2: Heat the pretreated industrial wastewater to 60-90° C., then add copper sulfate and hydrogen peroxide solution successively, adjust the pH to 3-7, preferably 4-6, and stir the reaction for 1-4 hours, preferably 1.5-2.5 hours.

[0014] As a transition metal, copper has excellent catalytic properties. Copper sulfate (CuSO4) can replace traditional iron catalysts in the Fenton reaction to generate active species, thereby improving oxidation efficiency. In addition, copper sulfate has the potential advantage of self-recycling copper ions in some copper-containing wastewater. By using copper sulfate as a catalyst with excellent performance under high temperature conditions, the oxidation efficiency can be improved, the scope of application can be expanded, and secondary pollution can be reduced, which is conducive to the efficient treatment of high-concentration, difficult-to-degrade industrial wastewater, and the utilization of wastewater resources and environmental protection treatment effects can be improved.

[0015] At the same time, the reaction is carried out at a high temperature of 30-90°C, which significantly accelerates the reaction rate. 2+ ) has good catalytic activity under high temperature conditions and can work synergistically with H2O2, so that the oxidant hydrogen peroxide (H2O2) generates a large number of hydroxyl radicals (·OH) in a short time. These free radicals have extremely strong oxidizing ability and can quickly attack organic pollutants in wastewater, break the molecular structure, and convert them into harmless small molecules, such as carbon dioxide (CO 2) and water (H2O).

[0016] Step 3: After the reaction is completed, the pH is adjusted to 9-11, preferably 9.5-10.5, by sodium hydroxide to generate precipitation in the reaction solution, the reaction solution is filtered to collect copper mud, sulfuric acid solution is added to the copper mud and mixed evenly, and then the filtrate is filtered to obtain a recovered copper sulfate solution; at the same time, the waste water after the reaction solution is filtered to remove the copper mud is neutralized, settled and re-filtered, and its chemical oxygen demand (COD) is detected to ensure that it meets the emission standards before discharge or secondary treatment.

[0017] Furthermore, in step one, the method for pre-treating industrial wastewater is filtration or sedimentation.

[0018] Furthermore, in step 2, the temperature of the industrial wastewater is adjusted by a heat-collecting constant-temperature magnetic agitator.

[0019] Furthermore, in step 2, the ratio of the amount of copper sulfate added to the volume of industrial wastewater is (2-4) g:1L.

[0020] Furthermore, in step 2, the ratio of the mass of hydrogen peroxide in the hydrogen peroxide solution to the pre-removal mass of COD in the industrial wastewater is (1-3):1, preferably (1.5-2.5):1.

[0021] Furthermore, the mass fraction of the hydrogen peroxide solution is 30%.

[0022] Furthermore, in step 2, when adding copper sulfate and hydrogen peroxide solution, keep stirring while slowly adding them dropwise. This is because most of the COD in industrial wastewater is too high, resulting in excessive dosage of hydrogen peroxide and violent reaction. Therefore, slowly adding them to the reaction system in a dropwise manner helps to avoid ineffective decomposition of hydrogen peroxide caused by local excessive dosage, thereby improving its utilization rate.

[0023] Furthermore, in step 2, the pH is adjusted by a pH adjuster, and the pH adjuster includes an acid and / or a base.

[0024] Furthermore, the acid in the pH adjuster includes sulfuric acid, and the alkali includes sodium hydroxide.

[0025] Furthermore, in step three, the ratio of the mass of sulfuric acid in the sulfuric acid solution to the mass of copper mud is 2:1.

[0026] Furthermore, the mass fraction of the sulfuric acid solution is 50%.

[0027] Furthermore, the recovered copper sulfate solution is reused in the high-temperature Fenton-like oxidation method for industrial wastewater treatment.

[0028] Beneficial effects of the present invention:

[0029] (1) In the high-temperature Fenton-like oxidation method for industrial wastewater treatment of the present invention, copper sulfide is used as a catalyst to carry out a Fenton-like oxidation reaction at high temperature. High temperature can significantly accelerate the reaction rate, so that copper ions have good catalytic activity under high temperature conditions and can synergize with H2O2, so that H2O2 generates a large number of hydroxyl radicals (·OH) in a relatively short period of time. These free radicals have extremely strong oxidizing ability and can quickly attack organic pollutants in wastewater, break the molecular structure, and convert them into harmless small molecules, such as carbon dioxide (CO 2) and water (H2O), thereby improving the treatment effect of industrial wastewater.

[0030] (2) In the high-temperature Fenton-like oxidation method for industrial wastewater treatment of the present invention, copper sulfate can replace the traditional iron catalyst in the Fenton reaction to generate active species, thereby improving the oxidation efficiency; in addition, copper sulfate has the potential advantage of self-recycling of copper ions in some copper-containing wastewater; by utilizing the excellent performance of copper sulfate as a catalyst under high temperature conditions, the oxidation efficiency is improved, the scope of application is expanded, and secondary pollution is reduced, which is conducive to achieving efficient treatment of high-concentration, difficult-to-degrade industrial wastewater, improving wastewater resource utilization and environmental protection treatment effects; applied to Fenton-like oxidation processes, it can promote the oxidation rate of hydrogen peroxide and improve the Fenton oxidation effect.

[0031] (3) In the high-temperature Fenton oxidation method for industrial wastewater treatment of the present invention, copper sulfate can be recovered after the catalytic reaction, and the recovery method is very simple and has high recovery efficiency. The recovered copper sulfate solution can be reused in the high-temperature Fenton oxidation method to treat industrial wastewater, thereby saving catalyst costs and reducing the pollution of the catalyst to the environment. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention discloses a high-temperature Fenton-like oxidation method for industrial wastewater treatment, comprising the following steps:

[0034] Step 1: Pre-treat industrial wastewater to remove solid particles and suspended matter by filtration or sedimentation.

[0035] Step 2: heat the pretreated industrial wastewater to 60-90° C. by a heat collecting constant temperature magnetic stirrer, first add copper sulfate, then slowly dropwise add hydrogen peroxide solution and keep stirring, the ratio of the amount of copper sulfate added to the volume of industrial wastewater is (2-4) g:1L, the ratio of the mass of hydrogen peroxide in the hydrogen peroxide solution to the pre-removal mass of COD in the industrial wastewater is (1-3):1, preferably (1.5-2.5):1, and the mass fraction of the hydrogen peroxide solution is 30%, and then adjust the pH to 3-7, preferably 4-6, by a pH adjuster such as sulfuric acid and / or sodium hydroxide, and stir the reaction for 1-4 hours, preferably 1.5-2.5 hours.

[0036] Step 3, after the reaction is completed, the pH is adjusted to 9-11, preferably 9.5-10.5, by sodium hydroxide to generate precipitation in the reaction solution, the reaction solution is filtered to collect copper mud, a sulfuric acid solution with a mass fraction of 50% is added to the copper mud and mixed evenly, and the ratio of the mass of sulfuric acid in the sulfuric acid solution to the mass of copper mud is 2:1; then the filtrate is filtered and collected to obtain a reusable copper sulfate solution; at the same time, the wastewater after the reaction solution is filtered to remove the copper mud is neutralized, settled and re-filtered, and its chemical oxygen demand (COD) is detected to ensure that it meets the emission standards before discharge or secondary treatment.

[0037] Copper sulfide is used as a catalyst to carry out Fenton-like oxidation reaction at high temperature. High temperature can significantly accelerate the reaction rate, so that copper ions have good catalytic activity under high temperature conditions, and can synergize with H2O2 to make H2O2 generate a large number of hydroxyl radicals (·OH) in a short time. These free radicals have extremely strong oxidizing ability and can quickly attack organic pollutants in wastewater, break the molecular structure, and convert them into harmless small molecules, such as carbon dioxide (CO 2) and water (H2O), thereby improving the treatment effect of industrial wastewater; copper sulfate can be recovered after the catalytic reaction, and the recovery method is very simple and the recovery efficiency is high. The recovered copper sulfate solution can be reused in a high-temperature Fenton oxidation method to treat industrial wastewater, thereby saving catalyst costs and reducing the pollution of the catalyst to the environment.

[0038] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0039] Example 1

[0040] The agrochemical industrial wastewater of a certain factory (the COD content was 37910 mg / L after testing) was treated. The wastewater was first filtered to remove solid particles and suspended matter, and then heated to 90°C. Then, copper sulfate pentahydrate was added to the wastewater in an amount of 3.8 g / L, and then a 30% hydrogen peroxide solution was added to the wastewater in an amount of 75.924 g / L. The pH value of the wastewater was adjusted to 5 by adding sulfuric acid and sodium hydroxide. After stirring for 2 hours, the wastewater was filtered, the filter copper mud was collected, and the filtrate wastewater was tested. After testing, the COD content of the filtrate wastewater was 8110.16 mg / L.

[0041] Next, the collected copper mud is recycled by adding a 50% sulfuric acid solution with a mass fraction of 4 times the copper mud to the copper mud, stirring evenly, and then filtering. The obtained filtrate is the recycled copper sulfate solution.

[0042] Example 2

[0043] The leachate from an airport (the COD content was 32007.5 mg / L after testing) was treated. The wastewater was first filtered to remove solid particles and suspended matter, and then heated to 90°C. Then, copper sulfate pentahydrate was added to the wastewater in an amount of 3 g / L, and then a 30% mass fraction hydrogen peroxide solution was added to the wastewater in an amount of 64.015 g / L. The pH value of the wastewater was adjusted to 5 by adding sulfuric acid and sodium hydroxide. After stirring for 2 hours, the wastewater was filtered, the filter copper mud was collected, and the filtrate wastewater was tested. After testing, the COD content of the filtrate wastewater was 4030 mg / L.

[0044] Next, the collected copper mud is recycled by adding a 50% sulfuric acid solution with a mass fraction of 4 times the copper mud to the copper mud, stirring evenly, and then filtering. The obtained filtrate is the recycled copper sulfate solution.

[0045] Example 3

[0046] The agrochemical industrial wastewater of a certain factory (the COD content was 35980 mg / L after testing) was treated. The wastewater was first filtered to remove solid particles and suspended matter, and then heated to 80°C. Then, copper sulfate pentahydrate was added to the wastewater in an amount of 4 g / L, and then a 30% mass fraction hydrogen peroxide solution was added to the wastewater in an amount of 71.960 g / L. The pH value of the wastewater was adjusted to 3 by adding sulfuric acid and sodium hydroxide. After stirring for 3 hours, the wastewater was filtered, the filter copper mud was collected, and the filtrate wastewater was tested. After testing, the COD content of the filtrate wastewater was 6560.52 mg / L.

[0047] Next, the collected copper mud is recycled by adding a 50% sulfuric acid solution with a mass fraction of 4 times the copper mud to the copper mud, stirring evenly, and then filtering. The obtained filtrate is the recycled copper sulfate solution.

[0048] Example 4

[0049] The agrochemical industrial wastewater of a certain factory (the COD content was 36110 mg / L after testing) was treated. The wastewater was first filtered to remove solid particles and suspended matter, and then heated to 70°C. Then, copper sulfate pentahydrate was added to the wastewater in an amount of 2.5 g / L, and then a 30% hydrogen peroxide solution was added to the wastewater in an amount of 108.33 g / L. The pH value of the wastewater was adjusted to 7 by adding sulfuric acid and sodium hydroxide. After stirring for 7 hours, the wastewater was filtered, the filter copper mud was collected, and the filtrate wastewater was tested. After testing, the COD content of the filtrate wastewater was 9458.11 mg / L.

[0050] Next, the collected copper mud is recycled by adding a 50% sulfuric acid solution with a mass fraction of 4 times the copper mud to the copper mud, stirring evenly, and then filtering. The obtained filtrate is the recycled copper sulfate solution.

[0051] Example 5

[0052] The agrochemical industrial wastewater of a certain factory (the COD content was 34120 mg / L after testing) was treated. The wastewater was first filtered to remove solid particles and suspended matter, and then heated to 90°C. Then, copper sulfate pentahydrate was added to the wastewater in an amount of 3.4 g / L, and then a 30% mass fraction hydrogen peroxide solution was added to the wastewater in an amount of 34.12 g / L. The pH value of the wastewater was adjusted to 5 by adding sulfuric acid and sodium hydroxide. After stirring for 2 hours, the wastewater was filtered, the filter copper mud was collected, and the filtrate wastewater was tested. After testing, the COD content of the filtrate wastewater was 12083.88 mg / L.

[0053] Next, the collected copper mud is recycled by adding a 50% sulfuric acid solution with a mass fraction of 4 times the copper mud to the copper mud, stirring evenly, and then filtering. The obtained filtrate is the recycled copper sulfate solution.

[0054] Test Example 1

[0055] The copper sulfate in the copper sulfate solution recovered in Example 1 was reused as a catalyst, and the operating steps and conditions were exactly the same as those in Example 1. After being reused 5 times, the filtrate wastewater was finally tested and the COD content of the filtrate wastewater was found to be 8124.11 mg / L.

[0056] Test Example 2

[0057] The copper sulfate in the copper sulfate solution recovered in Example 2 was reused as a catalyst, and the operating steps and conditions were exactly the same as those in Example 2. After being reused 5 times, the filtrate wastewater was finally tested and the COD content of the filtrate wastewater was 5729.34 mg / L.

[0058] Test Example 3

[0059] The copper sulfate in the copper sulfate solution recovered in Example 3 was reused as a catalyst, and the operating steps and conditions were exactly the same as those in Example 3. After being reused 5 times, the filtrate wastewater was finally tested and the COD content of the filtrate wastewater was found to be 6692.28 mg / L.

[0060] Test Example 4

[0061] The copper sulfate in the copper sulfate solution recovered in Example 4 was reused as a catalyst, and the operating steps and conditions were exactly the same as those in Example 4. After being reused 5 times, the filtrate wastewater was finally tested and the COD content of the filtrate wastewater was found to be 6391.47 mg / L.

[0062] Test Example 5

[0063] The copper sulfate in the copper sulfate solution recovered in Example 5 was reused as a catalyst, and the operating steps and conditions were exactly the same as those in Example 5. After being reused 5 times, the filtrate wastewater was finally tested and the COD content of the filtrate wastewater was found to be 12890.536 mg / L.

[0064] The removal rates of COD content after wastewater treatment in Examples 1-5 and Test Examples 1-5 were calculated and statistically analyzed, and the statistical results are listed in Table 1. Table 1 is as follows:

[0065] Table 1

[0066]

[0067]

[0068] By analyzing the data in Table 1, it can be seen that the removal rate of COD in industrial wastewater after the copper sulfate solution in Examples 1-5 is recycled is not much different from that when it is used for the first time, and the efficient removal effect is still maintained.

[0069] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A high temperature Fenton-like oxidation method for industrial wastewater treatment, characterized in that: The steps include: Step 1: pre-treat industrial wastewater to remove solid particles and suspended matter; Step 2: Heat the pretreated industrial wastewater to 60-90°C, then add copper sulfate and hydrogen peroxide solution, adjust the pH to 3-7, and stir the reaction for 1-4 hours; Step 3: After the reaction is completed, the pH is adjusted to 9-11, the reaction solution is filtered to collect copper mud, sulfuric acid solution is added to the copper mud and mixed evenly, and then the filtrate is filtered to collect the filtrate to obtain a recovered copper sulfate solution; at the same time, the waste water after the reaction solution is filtered to remove the copper mud is neutralized, settled and re-filtered, and its chemical oxygen demand is tested to ensure that it meets the emission standards before discharge or secondary treatment.

2. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 1, characterized in that: In step one, the method for pre-treating industrial wastewater is filtration or sedimentation.

3. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 1, characterized in that: In step 2, the ratio of the amount of copper sulfate added to the volume of industrial wastewater is (2-4) g:1L.

4. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 1, characterized in that: In step 2, the ratio of the mass of hydrogen peroxide in the hydrogen peroxide solution to the pre-removal mass of chemical oxygen demand in the industrial wastewater is (1-3):

1.

5. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 1, characterized in that: The mass fraction of the hydrogen peroxide solution is 30%.

6. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 1, characterized in that: In step 2, the pH is adjusted by a pH adjuster, wherein the pH adjuster comprises an acid and / or a base.

7. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 6, characterized in that: The acid in the pH adjuster includes sulfuric acid, and the alkali includes sodium hydroxide.

8. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 1, characterized in that: In step three, the ratio of the mass of sulfuric acid in the sulfuric acid solution to the mass of copper mud is 2:

1.

9. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 8, characterized in that: The mass fraction of the sulfuric acid solution is 50%.

10. The high temperature Fenton-like oxidation method for industrial wastewater treatment according to claim 1, characterized in that: The recovered copper sulfate solution is reused in the high-temperature Fenton-like oxidation method for industrial wastewater treatment.

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