Preparation method and application of catalyst for activating persulfate to degrade phenol wastewater

Abstract

The invention discloses a preparation method and application of a catalyst for degrading phenol wastewater by activating persulfate, and belongs to the technical field of environmental chemistry, the preparation method comprises the following steps: reacting a mixed solution of cobalt acetate, cerous nitrate, glucose and deionized water in a reaction kettle, and filtering, drying and calcining the obtained reactant to obtain the catalyst for degrading phenol wastewater by activating persulfate. The HOv-CoCeOx catalyst existing in a composite form of Co and Ce oxides is obtained, HOv-CoCeOx is applied to activate persulfate to degrade phenol wastewater, and phenolic substances in the phenol wastewater are converted into high-value products with known structures through an electron transfer mechanism. According to the preparation method and application of the catalyst for activating persulfate to degrade phenol wastewater, the preparation method is green, efficient and low in cost, high performance can still be guaranteed in various environments, the catalyst is suitable for wide application, and high-value products with known structures can be purposefully recycled.

Description

Technical Field

[0001] The invention relates to the technical field of environmental chemistry, and in particular to a preparation method and application of an activated persulfate catalyst for degrading phenol wastewater. Background Art

[0002] As a benzene series, phenolic organic compounds are widely used as raw materials in industrial production, especially in coal chemical industry, petrochemical industry, pharmaceutical industry and printing and dyeing industry. The large amount of emissions from these industries makes phenolic pollutants an important source of pollution in the environment. Studies have shown that the toxicity level of phenolic compounds is usually between 10-24 mg / L, and the lethal blood concentration is 1.5 mg / mL. Phenolic compounds have been included in the priority pollution list of the China Environmental Monitoring Group (covering 68 substances), and their treatment and control are particularly critical.

[0003] At present, advanced oxidation technology, as an effective environmental catalytic treatment method, mineralizes most organic pollutants by producing various active species with high redox potentials, thereby ensuring that they meet pollution emission standards. However, due to the limited number of free radicals produced in this process, the degree of mineralization is not high, and it is difficult to apply to complex water quality environments.

[0004] In the current research, Chinese patent CN118221252A proposed a method of using carbon nanotubes to activate persulfate, converting phenol-containing wastewater into high-value products through an electron transfer mechanism. However, due to the high price and cost of carbon nanotubes, this method is difficult to promote and utilize. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation method and application of an activated persulfate catalyst for degrading phenolic wastewater. The preparation method is green, efficient, and low-cost, and can still ensure high performance under various environments, is suitable for wide application, and can be purposefully recovered as a high-value product with a known structure.

[0006] To achieve the above object, the present invention provides a method for preparing an activated persulfate catalyst for degrading phenolic wastewater, comprising the following steps: S1. Weigh cobalt acetate, cerium nitrate and glucose, dissolve them in deionized water, and stir to obtain a mixed solution; S2, transferring the mixed solution to a polytetrafluoroethylene reactor and performing a high temperature reaction to obtain a reactant; S3. The reactants are filtered, dried and then calcined to obtain a catalyst, which is HOv-CoCeOx.

[0007] Preferably, in S1, the mass ratio of cobalt acetate, cerium nitrate and glucose is (4-6):(0.1-1):(2-4).

[0008] Preferably, in S2, the temperature of the high temperature reaction is 150-200° C., and the time of the high temperature reaction is 6-8 h.

[0009] Preferably, in S3, the calcination temperature is 500-600°C, the calcination time is 1-2h, and the calcination heating rate is 1-2°C / min.

[0010] The present invention provides an application of activated persulfate in degrading phenolic wastewater. The HOv-CoCeOx prepared according to the preparation method is applied to the degradation of phenolic wastewater.

[0011] Preferably, the specific steps are as follows: Weigh PMS and HOv-CoCeOx and add them into phenol wastewater, mix them evenly and react them at room temperature.

[0012] Preferably, the phenolic substance in the phenolic wastewater is one of phenol, 4-nitrophenol, trichlorophenol, 2,5-dichlorophenol and 2,6-dimethylphenol.

[0013] Preferably, the mass ratio of phenolic substances, PMS and HOv-CoCeOx in the phenolic wastewater is (0.05-0.2):(1-1.2):1.

[0014] Preferably, the reaction time is 10-20 min.

[0015] Preferably, the solution after the reaction is filtered and dried, acetonitrile is added, ultrasonicated in an ultrasonic cleaner, and then filtered, and the liquid is dried at room temperature to obtain a yellow precipitate, which is a phenolic polymer.

[0016] Therefore, the present invention adopts the above-mentioned preparation method and application of the activated persulfate catalyst for degrading phenol wastewater, which has the following beneficial effects: (1) The catalyst is prepared by a green and economical method, laying the foundation for large-scale promotion and application.

[0017] (2) The catalyst catalyzed PMS to remove phenol showed excellent performance, achieving 90% phenol removal in 10 minutes and complete degradation within 15 minutes; on the basis of efficient phenol removal, the COD removal rate also reached 80%.

[0018] (3) High-value chemicals can be obtained from the catalyst by simple washing with an organic solvent, and the phenolic polymer can shorten the industrial synthesis process.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1The present invention is a method for preparing an activated persulfate catalyst for degrading phenol wastewater and the PXRD diagrams of Example 1, Comparative Example 1 and Comparative Example 2; Figure 2 This is a characterization result diagram of a preparation method and application example 1 of an activated persulfate catalyst for degrading phenolic wastewater according to the present invention; Figure 3 It is a preparation method of an activated persulfate catalyst for degrading phenol wastewater of the present invention and a phenol and COD removal effect diagram of application example 1 and comparative example 2; Figure 4 It is a preparation method of an activated persulfate catalyst for degrading phenol wastewater and a diagram of the degradation effect of phenol under different simulated environments in Example 1 of the application of the present invention; Figure 5 It is a preparation method of an activated persulfate catalyst for degrading phenol wastewater and a degradation effect diagram of different simulated pollutants in application example 1 of the present invention; Figure 6 It is an it curve diagram of a preparation method and application example 1 of an activated persulfate catalyst for degrading phenol wastewater of the present invention; Figure 7 This is a graph showing the LC-Q-TOF-MS results of a preparation method and application example 1 of an activated persulfate catalyst for degrading phenolic wastewater according to the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0022] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0023] Embodiment 1 A method for preparing an activated persulfate catalyst for degrading phenolic wastewater comprises the following steps: S1. Weigh 5 g of cobalt acetate, 0.5 g of cerium nitrate and 3 g of glucose, dissolve them in 50 mL of deionized water, and stir to obtain a mixed solution; S2, transferring the mixed solution into a polytetrafluoroethylene reactor, and reacting at 200° C. for 6 h to obtain a reactant; S3. After filtering and drying, the reactants are calcined in air at a heating rate of 2°C / min, a calcination temperature of 500°C, and a calcination time of 1 h to obtain a catalyst, HOv-CoCeOx.

[0024] 12 mg of PMS and 10 mg of HOv-CoCeOx were added to 50 mL of phenol wastewater, with a phenol concentration of 10 mg / L. After mixing evenly, the mixture was reacted at room temperature for 15 min. The solution after the reaction was filtered and dried, and then acetonitrile was added. The solution was ultrasonically cleaned in an ultrasonic cleaner for 30 min, and then filtered. The liquid was dried at room temperature for 3 h to obtain a yellow precipitate, which was a phenol polymer.

[0025] Embodiment 2 The difference between Example 2 and Example 1 is that the phenol wastewater in Example 2 also includes 0.1 mM Cl - , the rest is the same as that of the first embodiment.

[0026] Embodiment 3 The difference between Example 3 and Example 1 is that the phenol wastewater in Example 3 also contains 0.1 mM SO4 2- , the rest is the same as that of the first embodiment.

[0027] Embodiment 4 The difference between Example 4 and Example 1 is that the phenol wastewater in Example 4 also includes 0.1mM CO3 2- , the rest is the same as that of the first embodiment.

[0028] Embodiment 5 The difference between Example 5 and Example 1 is that the phenol wastewater in Example 5 also includes 0.1mM NO3 - , the rest is the same as that of the first embodiment.

[0029] Embodiment 6 The difference between Example 6 and Example 1 is that the phenol wastewater in Example 6 also includes 0.1mM PO4 3- , the rest is the same as that of the first embodiment.

[0030] Embodiment 7 The difference between Example 7 and Example 1 is that the wastewater in Example 7 is 4-nitrophenol, and the rest is the same as Example 1.

[0031] Embodiment 8 The difference between Example 8 and Example 1 is that the wastewater in Example 8 is trichlorophenol, and the rest is the same as Example 1.

[0032] Embodiment 9 The difference between Example 9 and Example 1 is that the wastewater in Example 9 is 2,5-dichlorophenol, and the rest is the same as Example 1.

[0033] Embodiment 10 The difference between Example 1 and Example 1 is that the wastewater in Example 10 is 2,6-dimethylphenol, and the rest is the same as Example 1.

[0034] Comparative Example 1 Comparative Example 1 is different from Example 1 in that 5 g of cobalt acetate is not added, and the other parts are the same as Example 1, and the obtained catalyst is HOv-Ce.

[0035] Comparative Example 2 Comparative Example 1 is different from Example 1 in that 0.5 g of cerium nitrate is not added, and the other parts are the same as Example 1, and the obtained catalyst is HOv-Co.

[0036] Experimental Test 1 PXRD tests were performed on the HOv-CoCeOx prepared in Example 1, the HOv-Ce prepared in Comparative Example 1, and the HOv-Co prepared in Comparative Example 2. The results are as follows: Figure 1 As shown, the results indicate that HOv-CoCeOx is a material composed of Co and Ce oxides in a composite form. Figure 2 a in the figure represents the SEM image of HOv-CoCeOx. Figure 2 b in the figure represents the TEM image of HOv-CoCeOx. Figure 2 The cf in the figure represents the EDS-mapping diagram of HOv-CoCeOx. Figure 2 It can be seen that HOv-CoCeOx is a hollow microsphere with uniform metal distribution inside.

[0037] Experimental Test 2 The removal effects of HOv-CoCeOx prepared in Example 1 and HOv-Co prepared in Comparative Example 2 on phenol and COD were compared. Figure 3 As shown in the figure, at 15 min, HOv-CoCeOx degraded 94.34% of phenol and 76.67% of COD, which were much higher than 94.35% and 14.28% of HOv-Co. The results showed that HOv-CoCeOx had excellent catalytic performance.

[0038] Referring to Beijing Water Pollution Comprehensive Emission Standard (DB11 / 307-2013), Cl - 、SO4 2- 、CO3 2- 、NO3 - PO4 3- Set as interference factors in the simulated environment to compare their effects on phenol degradation. Figure 4 As shown in the figure, in the natural environment, HOv-CoCeOx can still maintain efficient degradation ability for phenol.

[0039] Table 1 Removal rate of phenol under different simulated environmental factors (unit: %)

[0040] The degradation effects of HOv-CoCeOx on 4-nitrophenol (4-NP), trichlorophenol (TCP), 2,5-dichlorophenol (DCP), 2,6-dimethylphenol (2,6-M-PN) and phenol (PN) were compared. Figure 5 As shown, HOv-CoCeOx is suitable for catalyzing the degradation of various phenolic compounds by PMS.

[0041] Table 2 Removal rates of different simulated pollutants (unit: %)

[0042] Experimental Test Three Since the redox reaction is carried out on the catalyst surface during the electron transfer process to degrade pollutants, the presence of the electron transfer process can be evaluated by detecting the current on the catalyst surface. The IT curve is a method for highly sensitively detecting the current on the sample electrode surface by adding a standard electrode and a reference electrode. The catalyst HOv-CoCeOx prepared in Example 1 was tested for IT. The results are shown in Figure 2. Figure 6 As shown. Figure 6 It can be seen that after the addition of peroxymonosulfate PMS, the surface current of HOv-CoCeOx fluctuated slightly, but after the addition of phenol, a large amount of current was generated on the catalyst surface, proving that when HOv-CoCeOx catalyzes PMS to remove phenol, the electrons of the redox reaction are transferred through the catalyst instead of undergoing a redox reaction in the liquid phase, that is, an electron transfer process. This proves that there is also an electron transfer process on the catalyst surface.

[0043] Experiment Test 4 The solution after ultrasonication in Example 1 was detected by LC-Q-TOF-MS, and the obtained product was as follows Figure 7 As shown, Figure 7 a in the figure represents the liquid phase LC liquid elution diagram, Figure 7 The b in the figure represents the MS test result. Symmetrical and asymmetrically substituted biaryl motifs exist in a series of drugs, herbicides and natural products, as well as conductive polymers and liquid crystal materials. In 2024, Zhang Changsheng's team at the Chinese Academy of Sciences demonstrated that CO and CC coupling of phenol plays a key role in the biosynthesis of natural products, such as vancomycin and teicoplanin. Therefore, the use of phenol polymers obtained from wastewater can shorten the industrial synthesis process and has commercial development prospects.

[0044] Therefore, the present invention adopts the preparation method and application of the above-mentioned activated persulfate catalyst for degrading phenolic wastewater. The preparation method is green, efficient, and low-cost, and can still ensure high performance under various environments. It is suitable for wide application, and obtains phenolic polymers with known structures. As a high-value product, it can be purposefully recovered.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing an activated persulfate catalyst for degrading phenolic wastewater, characterized in that: The following steps are involved: S1. Weigh cobalt acetate, cerium nitrate and glucose, dissolve them in deionized water, and stir to obtain a mixed solution; S2, transferring the mixed solution to a polytetrafluoroethylene reactor and performing a high temperature reaction to obtain a reactant; S3. The reactants are filtered, dried and then calcined to obtain a catalyst, which is HOv-CoCeOx.

2. The preparation method according to claim 1, characterized in that: In S1, the mass ratio of cobalt acetate, cerium nitrate and glucose is (4-6):(0.1-1):(2-4).

3. The preparation method according to claim 1, characterized in that: In S2, the temperature of the high temperature reaction is 150-200°C, and the time of the high temperature reaction is 6-8h.

4. The preparation method according to claim 1, characterized in that: In S3, the calcination temperature is 500-600°C, the calcination time is 1-2h, and the calcination heating rate is 1-2°C / min.

5. An application of activated persulfate to degrade phenolic wastewater, characterized in that: The HOv-CoCeOx prepared by the preparation method according to any one of claims 1 to 4 is applied to the degradation of phenolic wastewater.

6. The use according to claim 5, characterized in that: The specific steps are as follows: Weigh PMS and HOv-CoCeOx and add them into phenol wastewater, mix them evenly and react them at room temperature.

7. The use according to claim 6, characterized in that: The phenolic substance in phenolic wastewater is one of phenol, 4-nitrophenol, trichlorophenol, 2,5-dichlorophenol and 2,6-dimethylphenol.

8. The use according to claim 6, characterized in that: The mass ratio of phenolic substances, PMS and HOv-CoCeOx in phenolic wastewater is (0.05-0.2):(1-1.2):

1.

9. The use according to claim 6, characterized in that: The reaction time is 10-20 minutes.

10. The use according to claim 6, characterized in that: The solution after the reaction is filtered and dried, acetonitrile is added, ultrasonicated in an ultrasonic cleaning apparatus, and then filtered. The liquid is dried at room temperature to obtain a yellow precipitate, which is a phenolic polymer.

Images