A method for online in-situ activation of persulfate treatment of organic wastewater using copper oxide-supported carbon millimeter spheres.

Abstract

This invention discloses a method for online in-situ activation of persulfate to treat organic wastewater using copper oxide-loaded carbon millimeter spheres, comprising: 1) preparing copper oxide nanoparticle-loaded carbon millimeter spheres; 2) placing the prepared carbon millimeter spheres in a reaction column, starting a flow-through reaction system, and introducing organic pollutant wastewater containing persulfate for degradation reaction, thereby achieving efficient purification of organic wastewater. This invention addresses the problems of copper oxide nanomaterials, such as small size, large surface effect, strong adsorption capacity, poor stability, and easy aggregation, leading to difficulties in recovery, low treatment capacity, and low recycling rate in actual wastewater treatment. By loading copper oxide onto carbon millimeter spheres, the invention achieves the immobilization of copper oxide nanomaterials. Simultaneously, a flow-through reaction system is designed, in which the copper oxide-loaded carbon millimeter spheres are loaded into the reaction column. When persulfate flows through the millimeter spheres, a high concentration of active species is generated, and the organic matter in the mobile phase is rapidly degraded, achieving efficient purification of organic wastewater.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment technology, and in particular relates to a method for online in-situ activation of persulfate treatment of organic wastewater using copper oxide-supported carbon millimeter spheres. Background Technology

[0002] With the rapid development of pharmaceuticals, industry, and other fields, organic compounds are being applied in various sectors to increase production. For example, 2,4-dichlorophenol is commonly used in industrial manufacturing, but this process generates large amounts of wastewater. Discharge into water bodies can be toxic to aquatic life and human health, impairing the oxygen transport function of hemoglobin and causing strong irritation to the eyes, mucous membranes, respiratory system, and skin. Furthermore, it is difficult to degrade due to its aromatic ring structure and the presence of chlorinated atoms, making it challenging to treat using conventional processes and methods.

[0003] In recent years, advanced oxidation technologies have been found to have excellent removal effects on 2,4-dichlorophenol. Compared with persulfate and hydrogen peroxide activation systems, persulfate has advantages such as high water solubility, strong stability, and low cost, and has therefore attracted much attention. Currently, commonly used persulfate activation methods include alkaline activation, thermal activation, and photocatalysis.

[0004] However, the activation process suffers from low efficiency, high energy consumption, and secondary pollution, leading to a decline in pollutant treatment effectiveness. Therefore, choosing a more environmentally friendly persulfate activation technology would be beneficial for the application of this activation system in practical organic wastewater treatment.

[0005] Some metal oxides can activate persulfate in situ through their inherent active sites. For example, oxygen vacancies in iron oxide, cobalt oxide, and their alloys can directly activate persulfate, generating highly oxidizing free radicals (sulfate radicals, hydroxyl radicals, superoxide radicals) and non-free radicals (singlet oxygen). However, metal oxides are generally nanomaterials. Due to their small size, large surface effect, strong adsorption capacity, poor stability, and tendency to aggregate, their application in actual wastewater treatment is greatly limited by problems such as difficulty in recovery, low treatment capacity, and low recycling rate. Summary of the Invention

[0006] To address the aforementioned issues, this method overcomes the shortcomings of existing copper oxide nanomaterials, such as difficulty in regeneration, low processing capacity, and inability to be recycled. Copper oxide nanomaterials are grown and fixed in situ within macroscopic millimeter spheres. The copper oxide, uniformly dispersed within the pores, in situ activates persulfate to generate highly reactive free radicals. Relying on the mesoporous confinement effect within the millimeter spheres, organic matter can be rapidly degraded. Simultaneously, combined with flowing water conditions, the degradation products can quickly leave the catalyst's active sites, preventing catalyst poisoning and achieving long-term continuous removal of organic matter.

[0007] The method for treating organic wastewater by online in-situ activation of persulfate with copper oxide-supported carbon millimeter spheres includes the following steps:

[0008] 1) Preparation of carbon millimeter spheres supported on copper oxide nanoparticles;

[0009] 2) Place the carbon millimeter spheres prepared in step 1) in a reaction column, turn on the flow reaction system, and introduce organic pollutant wastewater containing persulfate for degradation reaction. The concentration of persulfate in the wastewater is 0.5~2 mmol / L, and the concentration of organic pollutant wastewater is below 80 mg / L. When persulfate flows through the carbon millimeter spheres, a high concentration of active species is generated, and the organic pollutants in the flowing wastewater are rapidly degraded, achieving efficient purification of organic wastewater.

[0010] Furthermore, the concentration of organic pollutant wastewater is 10-30 mg / L, and the volumetric flow rate of organic pollutant wastewater through the carbon millimeter ball bed in the reaction column is 5-20 BV / h.

[0011] Furthermore, the carbon millimeter spheres supported on copper oxide nanoparticles described in step 1) are prepared by the following method:

[0012] S1: Pretreatment of the substrate carbon millimeter spheres

[0013] Polystyrene millimeter spheres with sulfonic acid functional groups were selected as white-based carbon millimeter spheres and pretreated.

[0014] S2: Preparation of carbon millimeter spheres with copper ion adsorption

[0015] Prepare a divalent copper salt solution, put the pretreated substrate carbon millimeter balls prepared in step S1 into it, and after static and sufficient adsorption in a shaker, the white substrate carbon millimeter balls turn into blue carbon millimeter balls adsorbing copper ions. Finally, dry them for later use.

[0016] S3: Preparation of carbon millimeter spheres supported on copper hydroxide precursor

[0017] Prepare a mixed aqueous solution of NaOH and CTAB, put the copper ion adsorbed carbon millispheres prepared in step S2 into it, and react in a water bath at 50~120 ℃ for 0.5~2 h. The blue millispheres turn black. Rinse the surface of residual reagents with a large amount of ultrapure water, and dry to obtain millispheres loaded with copper oxide precursor for later use.

[0018] S4: Preparation of copper oxide-supported millimeter spheres

[0019] The carbon millimeter spheres supported by the copper hydroxide precursor prepared in step S3 were spread in a quartz boat and placed in a tube furnace. The temperature was slowly increased from room temperature to 140-160°C at a rate of 0.5-2°C / min, and then held for annealing for 0.5-2 hours to obtain copper oxide supported carbon millimeter spheres.

[0020] Further, the pretreatment steps for the carbon millimeter spheres in step S1 are as follows: the polystyrene millimeter spheres with sulfonic acid functional groups are washed with ultrapure water until colorless, then soaked in HCl solution with a mass fraction of 3-6% for 5-10 hours, then washed with water until neutral, then soaked in NaOH solution with a mass fraction of 3-6% for another 5-10 hours, then washed with water until neutral to remove impurities remaining in the spheres during the synthesis process, and dried to obtain the pretreated substrate carbon millimeter spheres.

[0021] Further, in step S2, the concentration of the divalent copper salt solution is 0.2~1 mol / L, the solid-liquid ratio of the substrate carbon millimeter spheres to the divalent copper salt solution is 0.05~0.2 g / mL, and the static adsorption time is 20-30 h.

[0022] Further, in step S3, the concentrations of NaOH and CTAB in the mixed aqueous solution of NaOH and CTAB are 1~1.5 mol / L and 0.03~0.1 mol / L, respectively, and the solid-liquid ratio of the carbon millimeter spheres adsorbed by copper ions to the mixed aqueous solution of NaOH and CTAB is 0.05~0.2 g / mL.

[0023] Furthermore, in step S4, the heating rate is 1 ℃ / min, and the holding annealing temperature is 150 ℃.

[0024] Furthermore, the organic pollutant is 2,4-dichlorophenol.

[0025] In this application, the 2,4-dichlorophenol wastewater generally originates from wastewater discharged by industries such as pharmaceutical factories, wood preservative factories, pesticide factories, paint factories, and paper and pulp processing plants.

[0026] The beneficial effects achieved by this invention are:

[0027] This invention grows and fixes copper oxide nanomaterials in situ within macroscopic millimeter spheres. The copper oxide, uniformly dispersed within the pores, activates persulfate in situ to generate highly active free radicals. Relying on the mesoporous confinement effect within the millimeter spheres, organic matter can be rapidly degraded. Simultaneously, combined with flowing water conditions, the degradation products can quickly leave the catalyst active sites, preventing catalyst poisoning and achieving long-term continuous removal of organic matter. Attached Figure Description

[0028] Figure 1 The image shown is a scanning electron microscope image of copper oxide-loaded carbon millimeter spheres obtained in Example 1.

[0029] Figure 2 This is a comparison chart showing the concentration of 2,4-dichlorophenol in the effluent under different wastewater treatment volumes during the flow degradation experiment of copper oxide-supported carbon millimeter balls in Example 2 and pure carbon millimeter balls in Comparative Example 1.

[0030] Figure 3 In the continued approval experiment, the pollutant concentration changes over time after treatment with copper oxide powder in Comparative Example 2 and copper oxide-loaded carbon millimeter balls in Example 3;

[0031] Figure 4 In the continued approval experiment, when treating wastewater with different pollutant concentrations, the graph shows the change of pollutant concentration over time after treatment with copper oxide-loaded carbon millimeter balls in Example 3 of this invention.

[0032] Figure 5 The image shows the external structure of the copper oxide-loaded carbon millimeter spheres obtained in Example 1. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0034] In this embodiment, the trough-type ultrasonic cleaner was purchased from Kunshan Shumei, model KQ5200DE; the vacuum filter was purchased from Shanghai Lichen Bangxi, model SHZ-D(III); and the automatic partial collector was purchased from Shanghai Huxi, model BS-100A.

[0035] All reagents used in the examples are commercially available products.

[0036] The polystyrene millimeter balls with sulfonic acid functional groups used in the embodiments of the present invention are D001 macroporous strong acid cation exchange resins, which are cation exchange resins with sulfonic acid groups (-SO3H) on styrene-divinylbenzene copolymers, purchased from Hangzhou Zhengguang Resin Co., Ltd.

[0037] Example 1: Preparation of copper oxide-supported carbon millimeter spheres

[0038] (a) Pretreatment of the substrate millimeter sphere

[0039] Polystyrene millimeter spheres with sulfonic acid functional groups were selected as the substrate spheres (particle size 0.3-0.6 mm). 50 g of substrate spheres were washed with 5 L of ultrapure water until colorless, soaked in 200 ml of 4% HCl solution for 8 h, then washed with water until neutral, and then soaked in 400 ml of 4% NaOH solution for another 8 h. After washing with water until neutral, the residual impurities in the spheres during the synthesis process were removed. Finally, the spheres were dried in a vacuum oven at 60 °C to obtain the pretreated substrate millimeter spheres.

[0040] (b) Preparation of millimeter spheres for copper ion adsorption

[0041] Prepare 100 mL of 0.5 mol / L Cu(NO3)2·H2O solution, add 5 g of the pretreated substrate millispheres prepared in step (a), and statically adsorb in a shaker for 24 h. The white substrate millispheres turn into blue millispheres adsorbing copper ions. Finally, dry them under vacuum at 60 °C for later use.

[0042] (c) Preparation of millimeter spheres supported on copper hydroxide precursor

[0043] Prepare 100 ml of a mixed solution of 1.25 mol / L NaOH and 0.06 mol / L CTAB, add 5 g of copper ion-adsorbed millimeter spheres prepared in step (b), and react in an 80 ℃ water bath for 1 h. The blue millimeter spheres turn black. Rinse the surface of residual reagents with a large amount of ultrapure water, and dry under vacuum at 60 ℃ to obtain millimeter spheres loaded with copper oxide precursor for later use.

[0044] (d) Preparation of copper oxide-supported millimeter spheres

[0045] The copper hydroxide precursor-loaded millimeter spheres prepared in step (c) were spread in a quartz boat and placed in a tube furnace. The temperature was increased at a rate of 1 °C / min within a 150 °C range. After annealing at 150 °C for 1 h, copper oxide-loaded millimeter spheres were obtained.

[0046] SEM image of copper oxide-supported carbon millimeter spheres obtained in Example 1 is shown below. Figure 1 As shown in the image, and its external structure photograph is as follows. Figure 5 As shown, this catalyst material has advantages such as high mechanical strength, good hydrodynamic properties, fast ion diffusion rate, resistance to swelling, and excellent adsorption performance.

[0047] Example 2: Flow Degradation Experiment of 2,4-Dichlorophenol

[0048] (1) The copper oxide-supported carbon millimeter sphere material prepared in Example 1 was packed into a cylindrical reaction column with a packing volume of 5 mL; it was placed in a flow reaction system and fed with a mixed solution of 20 mg / L 2,4-dichlorophenol and 238 mg / L sodium persulfate at a feed rate of 1 mL / min.

[0049] (2) The effluent solution from step (2) is collected by an automatic collector. The content of pollutants in the aqueous solution is determined by high performance liquid chromatography. The breakthrough point is recorded when the concentration of 2,4-dichlorophenol in the effluent is greater than 0.2 mg / L. The removal efficiency is calculated and the concentration of 2,4-dichlorophenol in the effluent under different wastewater treatment volumes is recorded.

[0050] Comparative Example 1: Preparation of Pure Carbon Millimeter Spheres

[0051] The preparation steps of the adsorbent material in Comparative Example 1 were repeated in Example 1, except that step (b) copper ion adsorption was omitted. All other operations were the same as in Example 1, and pure carbon millimeter spheres were finally obtained.

[0052] The pure carbon millimeter balls prepared in Comparative Example 1 were subjected to a flow degradation experiment of 2,4-dichlorophenol according to the method in Example 2.

[0053] Example 3: Continued Batch Degradation Experiment of 2,4-Dichlorophenol

[0054] The copper oxide-supported carbon millisphere material (0.5 g) prepared in Example 1 was placed in a 150 mL Erlenmeyer flask, and 50 mL of a wastewater solution containing 2,4-dichlorophenol was added. The wastewater solution contained sodium persulfate as an oxidant, with a 2,4-dichlorophenol concentration of 20 mg / L and a sodium persulfate concentration of 238 mg / L. The Erlenmeyer flask was placed in a constant-temperature shaker at 25°C and 200 rpm for thorough adsorption. The concentration of 2,4-dichlorophenol in the solution was tested at different treatment times.

[0055] Comparative Example 2: Preparation of Copper Oxide Nanomaterials

[0056] The preparation steps of the adsorbent material in Comparative Example 2 were the same as those in Example 1, except that the process of loading carbon millimeter spheres was not performed. That is, in step (c), Cu(NO3)2·H2O solution was directly titrated and precipitated with a mixed solution of NaOH and CTAB. All other operations were the same as in Example 1, and copper oxide nanomaterials were finally obtained.

[0057] Comparative Example 3

[0058] The experimental procedures in this embodiment are the same as those in Example 3, except that the initial concentration of pollutants is 10 mg / L.

[0059] Comparative Example 4

[0060] The experimental procedures in this embodiment are the same as those in Example 3, except that the initial concentration of pollutants is 40 mg / L.

[0061] Comparative Example 5

[0062] The experimental procedures in this embodiment are the same as those in Example 3, except that the initial concentration of pollutants is 60 mg / L.

[0063] Comparative Example 6

[0064] The experimental procedures in this embodiment are the same as those in Example 3, except that the initial concentration of pollutants is 80 mg / L.

[0065] from Figure 1 As can be seen, in the copper oxide-supported carbon millimeter-sphere material, the copper oxide nanomaterials are encapsulated on the surface of the millimeter-spheres and confined within the pores of the millimeter-spheres, exhibiting a uniform distribution. This not only effectively immobilizes the copper oxide nanomaterials, preventing them from agglomerating or leaking, but also facilitates full contact and reaction between the copper oxide millimeter-spheres and pollutants.

[0066] from Figure 2 It can be seen that, in the online flow column experiment, the copper oxide-supported carbon millimeter sphere material can continuously process 1300 BV of organic pollutants. Compared with carbon-based millimeter spheres without copper oxide nanoparticles, the copper oxide-supported carbon millimeter sphere material can achieve efficient and continuous online in-situ activation of persulfate, generating high concentrations of active species for the degradation of 2,4-dichlorophenol.

[0067] from Figure 3 It can be seen that in the sequencing batch reaction, copper oxide-supported carbon millimeter-sphere material maintains the high efficiency of copper oxide nanomaterials in activating sodium persulfate and can rapidly remove 2,4-dichlorophenol.

[0068] from Figure 4 It can be seen that copper oxide-supported carbon millimeter balls can achieve efficient removal of 2,4-dichlorophenol at different concentrations, and even at high concentrations (80 mg / L), 80% removal can still be achieved.

[0069] In summary, copper oxide uniformly dispersed in the channels of copper oxide-supported carbon millimeter spheres can activate persulfate in situ to generate highly active free radicals. With the help of the mesoporous confinement effect within the millimeter spheres, organic matter can be rapidly degraded, achieving long-term continuous removal of organic matter.

[0070] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A method for treating organic wastewater by online in-situ activation of persulfate with copper oxide-supported carbon millimeter spheres, characterized in that, Includes the following steps: 1) Carbon millimeter spheres supported on copper oxide nanoparticles were prepared by the following method: S1: Pretreatment of the substrate carbon millimeter spheres Polystyrene millimeter spheres with sulfonic acid functional groups were selected as white-based carbon millimeter spheres and pretreated. S2: Preparation of carbon millimeter spheres with copper ion adsorption Prepare a divalent copper salt solution, put the pretreated substrate carbon millimeter balls prepared in step S1 into it, and after static and sufficient adsorption in a shaker, the white substrate carbon millimeter balls turn into blue carbon millimeter balls adsorbing copper ions. Finally, dry them for later use. The concentration of the divalent copper salt solution is 0.2~1 mol / L, the solid-liquid ratio of the substrate carbon millimeter spheres to the divalent copper salt solution is 0.05~0.2 g / mL, and the static adsorption time is 20-30 h; S3: Preparation of carbon millimeter spheres supported on copper hydroxide precursor Prepare a mixed aqueous solution of NaOH and CTAB, put the copper ion adsorbed carbon millispheres prepared in step S2 into it, and react in a water bath at 50~120℃ for 0.5~2 h. The blue millispheres turn black. Rinse the surface of residual reagents with a large amount of ultrapure water, and dry to obtain millispheres loaded with copper oxide precursor for later use. S4: Preparation of copper oxide-supported millimeter spheres The carbon millimeter spheres loaded with the copper hydroxide precursor prepared in step S3 were spread in a quartz boat and placed in a tube furnace. The temperature was slowly increased from room temperature to 140-160°C at a rate of 0.5-2°C / min, and then held for annealing for 0.5-2 hours to obtain copper oxide loaded carbon millimeter spheres. 2) Place the carbon millimeter spheres prepared in step 1) in a reaction column, turn on the flow reaction system, and introduce organic pollutant wastewater containing persulfate for degradation reaction. The concentration of persulfate in the wastewater is 0.5~2 mmol / L, and the concentration of organic pollutant wastewater is below 80 mg / L. When persulfate flows through the carbon millimeter spheres, a high concentration of active species is generated, and the organic pollutants in the flowing wastewater are rapidly degraded, achieving efficient purification of organic wastewater.

2. The method for treating organic wastewater by online in-situ activation of persulfate with copper oxide-supported carbon millimeter spheres as described in claim 1, characterized in that, The concentration of organic pollutant wastewater is 10-30 mg / L, and the volumetric flow rate of organic pollutant wastewater through the carbon millimeter ball bed in the reaction column is 5-20 BV / h.

3. The method for treating organic wastewater by online in-situ activation of persulfate with copper oxide-supported carbon millimeter spheres as described in claim 1, characterized in that, The pretreatment steps for the carbon millimeter spheres in step S1 are as follows: The polystyrene millimeter balls with sulfonic acid functional groups were washed with ultrapure water until colorless, then soaked in 3-6% HCl solution for 5-10 hours, washed with water until neutral, and then soaked in 3-6% NaOH solution for another 5-10 hours. After washing with water until neutral, the impurities remaining in the synthesis process were removed, and the balls were dried to obtain the pretreated substrate carbon millimeter balls.

4. The method for treating organic wastewater by online in-situ activation of persulfate with copper oxide-supported carbon millimeter spheres as described in claim 1, characterized in that... In step S3, the concentrations of NaOH and CTAB in the mixed aqueous solution of NaOH and CTAB are 1~1.5 mol / L and 0.03~0.1 mol / L, respectively, and the solid-liquid ratio of the carbon millimeter balls adsorbed by copper ions to the mixed aqueous solution of NaOH and CTAB is 0.05~0.2 g / mL.

5. The method for treating organic wastewater by online in-situ activation of persulfate with copper oxide-supported carbon millimeter spheres as described in claim 1, characterized in that... In step S4, the heating rate is 1 ℃ / min, and the holding annealing temperature is 150 ℃.

6. The method for treating organic wastewater by online in-situ activation of persulfate with copper oxide-supported carbon millimeter spheres as described in claim 1, characterized in that... The organic pollutant is 2,4-dichlorophenol.

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