Method for realizing sustained degradation of pollutants at low dosage based on self-assembly induced carbon confinement material

Abstract

The present application belongs to the technical field of wastewater treatment, and provides a method for realizing continuous degradation of pollutants under low dosage of self-assembled induced carbon confinement material, comprising the following steps: adding peroxyacetic acid and carbon confinement material into wastewater containing organic pollutants, treating the wastewater under stirring, and activating the peroxyacetic acid by the carbon confinement material to generate hydroxyl radicals, organic radicals, singlet oxygen and Co(IV) to degrade the organic pollutants in the wastewater during the wastewater treatment; the carbon confinement material is composed of a cobalt material and a nitrogen-doped carbon material coated on the cobalt material, the cobalt material is composed of Co and CoO, and the carbon confinement material is a nanoparticle with a core-shell structure. The present application can realize efficient utilization of the oxidant peroxyacetic acid and mediate continuous degradation of micro-pollutants under low dosage of the carbon confinement material, thereby reducing the treatment cost of wastewater containing organic pollutants.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and relates to a method for achieving continuous degradation of pollutants at a low dosage based on self-assembly-induced carbon confined materials. Background Art

[0002] In recent years, risk prevention of new pollutants has received increasing attention. New pollutants have characteristics such as biological toxicity, environmental persistence, and bioaccumulation. Their environmental risks are hidden and difficult to control. Take naproxen, a new pollutant containing an aromatic ring structure, as an example. Naproxen is a typical non-steroidal anti-inflammatory drug and is widely used as an antibiotic worldwide. For this type of antibiotic micropollutants that contain aromatic ring structures, have poor water solubility but high fat solubility, and are metabolically stable, water bodies are the main carriers of their distribution in the environment. Traditional methods such as adsorption, flocculation, and biological treatment are difficult to effectively remove such micropollutants. Compared with traditional treatment methods, advanced oxidation processes (AOPs) can achieve high-efficiency removal of antibiotics with low secondary pollution. They have been applied to the removal of difficult-to-degrade micropollutants and deep treatment of sewage.

[0003] Advanced oxidation processes based on peracetic acid (PAA-AOPs) have received widespread attention in recent years due to their high efficiency and environmental friendliness. Compared with traditional advanced oxidation processes, PAA-AOPs have a wider pH range of application. The oxidant peracetic acid (PAA) itself does not produce harmful by-products and has both oxidation and sterilization functions. In existing reports, energy inputs such as ultraviolet light, ultrasound, sunlight and heat energy, catalysts such as transition metal ions and their compounds, and non-metallic carbon materials can all achieve the OO bond breakage of PAA, thereby activating PAA to produce hydroxyl radicals (·OH), organic free radicals (RO·), singlet oxygen ( 1 The PAA is activated by one or more active species, such as oxygen (O2) and high-valent metals, effectively degrading micropollutants. Compared to using homogeneous catalytic materials to activate PAA, using heterogeneous catalytic materials can reduce the leaching of metal ions, thereby reducing secondary pollution, and also enable the recycling of catalytic materials.

[0004] Among the many catalytic materials used to activate PAA, cobalt-based heterogeneous catalytic materials have demonstrated excellent performance in PAA activation. However, the limited effective activation sites of cobalt-based heterogeneous catalytic materials, the consumption of PAA by the water environment matrix, the occurrence of side reactions during the activation of PAA by cobalt-based catalytic materials, and the low activation efficiency have led to low utilization efficiency of PAA and catalytic materials in wastewater treatment. The resulting high cost problem is the biggest obstacle to the engineering application of this technology. At the same time, the actual treatment of wastewater is often a continuous and long-term process. How to achieve the continuous degradation of micropollutants in water bodies is also a key to reducing the cost of wastewater treatment. Therefore, if the efficiency of cobalt-based heterogeneous catalytic materials in activating PAA can be improved, the efficient utilization of PAA and the continuous degradation of micropollutants can be achieved at low dosages, it will have a positive significance for promoting the engineering application of PAA-AOPs. Summary of the Invention

[0005] To address the problems of high dosages of catalytic materials and peracetic acid and high engineering application costs in existing peracetic acid-based advanced oxidation processes, the present invention provides a method for achieving sustained degradation of pollutants at low dosages based on self-assembled induced carbon-confined materials. This method achieves efficient utilization of the oxidant peracetic acid at low carbon-confined material dosages, mediates the sustained degradation of micropollutants, and reduces the treatment cost of wastewater containing organic pollutants.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0007] The method for achieving continuous degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials includes the following steps:

[0008] adding peracetic acid and a carbon-confined material to wastewater containing organic pollutants, and treating the wastewater under stirring conditions, wherein during the wastewater treatment process, the carbon-confined material activates the peracetic acid to generate hydroxyl radicals, organic free radicals, singlet oxygen, and Co(IV) to degrade the organic pollutants in the wastewater;

[0009] The carbon confined material is composed of a cobalt material and a nitrogen-doped carbon material coating the cobalt material. The cobalt material is composed of Co and CoO. The carbon confined material is a nanoparticle with a core-shell structure.

[0010] In the above technical solution, the cobalt content in the carbon confined material is preferably 18 wt% to 23 wt%, and the nitrogen content is preferably 1.0 wt% to 2.4 wt%.

[0011] In the above technical solution, in the nitrogen-doped carbon material, the carbon phase composition is graphitized carbon and disordered carbon, and the intensity ratio of the D band to the G band in the Raman spectrum of the nitrogen-doped carbon material is 0.98 to 1.85.

[0012] In the above technical solution, the functional groups contained in the nitrogen-doped carbon material include CH, CO, C=NC and NH.

[0013] In the above technical solution, the particle size of the carbon confinement material is preferably 10 to 20 nm.

[0014] In the above technical solution, the carbon confined material has a mesoporous structure with an average pore diameter not exceeding 10 nm.

[0015] In the above technical solution, the preferred method for preparing the carbon confined material is as follows:

[0016] (1) adding dopamine hydrochloride and a block copolymer to an ethanol-water solution, ultrasonically treating the solution to form block copolymer-dopamine hydrochloride micelles, adding a water-soluble cobalt salt to the block copolymer-dopamine hydrochloride micelles, mixing the mixture thoroughly, adding 1,3,5-trimethylbenzene and ammonia water, stirring the mixture to react for 3-5 hours, separating the solid and liquid, and washing the solid phase;

[0017] In this step, dopamine hydrochloride is added to an ethanol-water solution at a mass ratio of 1:(1.5-3) to the block copolymer, the concentration of dopamine hydrochloride in the ethanol-water solution is controlled to be 4-8 g / L, the concentration of the water-soluble cobalt salt in the block copolymer-dopamine hydrochloride micelles is controlled to be 2-4 mmol / L, 1,3,5-trimethylbenzene and ammonia water are added at a volume ratio of (0.9-1.2):100 and (1-2):100 to the ethanol-water solution; the volume content of ethanol in the ethanol-water solution is 50%-60%;

[0018] (2) The solid phase obtained in step (1) is heated to 340-360° C. under N 2 atmosphere and kept warm for 2-4 hours, then heated to 800-900° C. and kept warm for 1-3 hours.

[0019] Furthermore, in the above technical solution, when preparing the carbon confined material, the preferred block copolymer is polyethylene oxide-block-polypropylene oxide-block-polyethylene oxide (PEO-PPO-PEO), for example, Pluronic F127 and P123, and the preferred block copolymer can also be polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol (PEG-PPG-PEG), for example, Pluronic F108 and F124.

[0020] In the above technical solution, when preparing the carbon confined material, the water-soluble cobalt salt can be cobalt nitrate, cobalt sulfate, etc.

[0021] In the above technical solution, the adding amount of peracetic acid in the wastewater is preferably controlled to be 50-400 μmol / L, and more preferably, the adding amount of peracetic acid in the wastewater is controlled to be 50-200 μmol / L.

[0022] In the above technical solution, the adding amount of the carbon confinement material in the wastewater is preferably controlled to be 5-50 mg / L, and more preferably, the adding amount of the carbon confinement material in the wastewater is controlled to be 5-30 mg / L.

[0023] In the above technical solution, the wastewater treatment time can be determined according to the water quality of the specific wastewater (for example, the type and concentration of organic pollutants), and generally, the treatment is stopped until the removal rate of the organic pollutants in the wastewater reaches equilibrium. Generally, the wastewater treatment time is controlled to be 10-120 min.

[0024] In the above technical solution, during the wastewater treatment, the temperature of the wastewater does not substantially affect the degradation efficiency and effect of the organic pollutants. In order to save the wastewater treatment cost, the wastewater treatment can be performed at room temperature, for example, the temperature of the wastewater can be controlled to be 5-35℃.

[0025] In the above technical solution, during the wastewater treatment, the stirring condition is controlled so that the carbon confinement material is in a fluidized state in the wastewater.

[0026] In the above technical solution, according to the different block copolymers used for preparing the carbon confinement material, the organic free radicals generated by activating peracetic acid by the carbon confinement material are CH3· and CH3COO·, or only CH3COO·.

[0027] In the above technical solution, the organic pollutants include, but are not limited to, phenol (PE), bisphenol A (BPA), sulfamethoxazole (SMX), sulfamerazine (SMZ), 4-chlorophenol (4-CP), ampicillin (AMP), naproxen (NAP), and sulfamethoxazole (SMX).

[0028] The present application proves by experiments that the carbon confinement material has excellent recycling performance. In practical applications, the carbon confinement material can be recycled to reduce the wastewater treatment cost. Generally, the recycling number of the carbon confinement material can reach 3-4 times.

[0029] The main reasons why the present application can realize the efficient use of the oxidant peracetic acid under a low carbon confinement material adding dosage are as follows:

[0030] The present invention uses a self-assembly polymerization strategy to confine Co@CoO nanoparticles within a nitrogen-doped carbon material to prepare a carbon-confined material. On the one hand, the coating of the nitrogen-doped carbon material shell effectively reduces the leaching of metal ions, solving the problem of easy agglomeration and inactivation of metal nanoparticles. On the other hand, confining the Co@CoO nanoparticles within the nitrogen-doped carbon material in the form of a core-shell structure effectively modulates the electronic structure of the active site and achieves efficient catalytic activation of peracetic acid through the electronic synergy between Co and CoO. The nanoconfinement of the nitrogen-doped carbon material can achieve the chemical conversion rate and selectivity of pollutants under milder conditions by enriching reactants, stabilizing transition states, and changing the internal surface adsorption potential and redox state, thereby improving the utilization efficiency of oxidants, carbon-confined materials, and active species.

[0031] Compared with the prior art, the technical solution provided by the present invention produces the following beneficial technical effects:

[0032] 1. The present invention provides a method for achieving continuous degradation of pollutants at low dosages based on self-assembly-induced carbon-confined materials. The method is based on carbon-confined materials activating peracetic acid to produce advanced oxidation active species, thereby achieving efficient degradation of organic pollutants. The carbon-confined material is composed of a cobalt material and a nitrogen-doped carbon material coated with a cobalt material. The cobalt material is composed of Co and CoO, and the carbon-confined material is a nanoparticle with a core-shell structure. Due to the increase in the activity of the carbon-confined material, the method of the present invention can achieve a higher oxidant utilization rate at a low carbon-confined material dosage. Therefore, the present invention has a significant advantage in the dosage of the agent, can reduce the degradation cost of organic pollutants, and promote the engineering application of the method.

[0033] 2. Experiments have demonstrated that during the treatment of wastewater containing organic pollutants using the method described herein, the carbon-confined material activates peracetic acid to produce hydroxyl radicals, organic free radicals, singlet oxygen, and Co(IV), which degrade the organic pollutants in the wastewater. Furthermore, the confinement effect of the carbon-confined material allows for the persistent presence of active species, thereby enabling the sustained degradation of organic pollutants by these active species. Specifically, after 2 hours of reaction, the carbon-confined material / peracetic acid system can still detect the presence of active species via EPR, with the adduct peak area continuously increasing. Even after 120 hours of continuous flow operation, the system can achieve a 70% degradation efficiency for naproxen. Without the addition of peracetic acid or carbon-confined material, the method can achieve complete degradation of naproxen in three cycles. These factors contribute to effectively reducing the treatment cost of wastewater containing organic pollutants.

[0034] 3. The method of the present invention is mainly used in combination with biological treatment to improve the biodegradability of wastewater biological treatment while removing organic pollutants in wastewater. In the wastewater treatment process, the carbon-confined material activates peracetic acid to produce organic matter such as acetic acid, which can provide a carbon source for the growth of microorganisms in the biological treatment stage. Therefore, when the method of the present invention is used in conjunction with biological treatment, the addition of the carbon source can be reduced, thereby reducing the cost of adding the carbon source. At the same time, the preparation method of the carbon-confined material of the present invention is simple, the conditions are mild, and it has a large cost advantage during preparation. In addition, the method of the present invention can achieve the continuous activation of peracetic acid and the continuous generation of higher oxidation species under the condition of low carbon-confined material dosage, which is conducive to reducing the cost of adding the agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Figures (a) and (b) are the SEM images and EDS-mapping images of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1, respectively.

[0036] Figure 2 Figures (a) and (b) are the TEM and HRTEM images of Co@CoO-P123 prepared in Example 1. Figure 2 Figures (c) and (d) are the TEM and HRTEM images of Co@CoO-F127 prepared in Example 1.

[0037] Figure 3 Figures (a) and (b) are BET diagrams of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1. Figure 3 Figure (c) is the XRD spectra of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1. Figure 3 Figure (d) is the FTIR spectra of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1.

[0038] Figure 4 Figure (a) is the full XPS spectrum of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1. Figure 4 Figure (b) is the Tafel curve of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1, as well as the control Co and control CoO.

[0039] Figure 5 Figures (a) and (b) are the Raman spectra of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1, respectively.

[0040] Figure 6Figure (a) shows the change of [NAP] / [NAP]0 with treatment time when NAP is degraded in Example 3. Figure 5 Figure (b) shows the C / C0 test results of Example 4 for degradation of different pollutants. Figure 5 Figure (c) shows the change of [NAP] / [NAP]0 with treatment time when different concentrations of NAP are degraded in Example 5. Figure 5 Figure (d) shows the change of [SMX] / [SMX]0 with treatment time when Example 6 degrades SMX in actual water.

[0041] Figure 7 Figure (a) shows the change of the reaction rate constant of NAP degradation with the addition amount of PAA in Example 7. Figure 7 Figure (b) shows the change of the reaction rate constant of NAP degradation in Example 8 with the addition amount of Co@CoO-P123.

[0042] Figure 8 This is the consumption of PAA in Example 7.

[0043] Figure 9 Figures (a) and (b) are the persistence test results of the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system during PAA activation and the stability test results during continuous flow operation in Examples 8 to 9.

[0044] Figure 10 is the effect of different quenchers on NAP degradation.

[0045] Figure 11 Figures (a) and (b) are the DMPO-OH adduct signal peaks of the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system; Figure 9 Figures (c) and (d) are the TEMPO signal peaks of Co@CoO-P123 / PAA system and Co@CoO-F127 / PAA system.

[0046] Figure 12 Figures (A) and (B) show the degradation of benzoic acid and the generation of 7-hydroxycoumarin using benzoic acid and coumarin as hydroxyl probes.

[0047] Figure 13 Figures (A) and (B) show the consumption of PMSO and the generation of PMSO2.

[0048] Figure 14 This is the generation of TEMPO-RO when TEMPO is used as a probe. DETAILED DESCRIPTION

[0049] The following examples further illustrate the method provided by the present invention for achieving sustained pollutant degradation at low dosages based on self-assembly-induced carbon confined materials. It is important to note that the following examples are intended only to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by persons skilled in the art to the present invention based on the above-mentioned invention are still within the scope of protection of the present invention.

[0050] Example 1

[0051] In this embodiment, a carbon confined material, specifically a nitrogen-doped confined Co@CoO core-shell material, is prepared by the following steps:

[0052] (1) Dopamine hydrochloride and the block copolymer are added to an ethanol-water solution to a concentration of 5 g / L and 10 g / L, respectively, and ultrasonically treated until the components are fully dissolved to obtain block copolymer-dopamine hydrochloride micelles. Cobalt nitrate hexahydrate is added to the block copolymer-dopamine hydrochloride micelles to a concentration of 2 mmol / L, and the mixture is stirred and mixed uniformly. 1,3,5-trimethylbenzene and ammonia water are then rapidly added in sequence at a speed of 500 rpm / min. After continuous stirring for 30 minutes, the speed is adjusted to 300 rpm / min, and stirring is continued for 3 hours. The resulting mixture is centrifuged, and the resulting solid particles are washed multiple times with ethanol and deionized water. The solid particles are collected and dried.

[0053] In this step, the ethanol-water solution was prepared by mixing deionized water and anhydrous ethanol in a volume ratio of 2:3. 1,3,5-trimethylbenzene and aqueous ammonia were added at a volume ratio of 0.9:100 and 1.5:100, respectively, to the ethanol-water solution. Two sets of experiments were conducted in this step: the first set used the block copolymer Pluronic F127, and the second set used the block copolymer P123.

[0054] (2) The dried solid particles were heated to 350°C at a heating rate of 2°C / min under N2 atmosphere and kept at this temperature for 3 h. Then, the temperature was increased to 800°C at a heating rate of 2°C / min and kept at this temperature for 2 h to obtain a nitrogen-doped confined Co@CoO core-shell material. When the block copolymer used was P123, the prepared nitrogen-doped confined Co@CoO core-shell material was referred to as Co@CoO-P123, or Co-P123 for short. When the block copolymer used was Pluronic F127, the prepared nitrogen-doped confined Co@CoO core-shell material was referred to as Co@CoO-F127, or CoO-F127 for short.

[0055] Example 2

[0056] In this example, the nitrogen-doped confined Co@CoO core-shell material prepared in Example 1 was characterized.

[0057] The nitrogen-doped confined Co@CoO core-shell material prepared in Example 1 was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), elemental distribution (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), Raman spectroscopy (Raman) and electrochemical workstation.

[0058] Figure 1 Figures (a) and (b) are the SEM images and EDS-mapping images of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1, respectively. Figure 2 Figures (a) and (b) are the TEM and HRTEM images of Co@CoO-P123 prepared in Example 1. Figure 2 Figures (c) and (d) are the TEM and HRTEM images of Co@CoO-F127 prepared in Example 1. Figure 3 Figures (a) and (b) are BET diagrams of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1. Figure 3 Figure (c) is the XRD spectra of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1. Figure 3 (d) is the FTIR spectrum of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1. Figure 4 Figure (a) is the full XPS spectrum of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1. Figure 4 Figure (b) is the Tafel curve of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1, as well as the control Co and control CoO. Figure 5 Figures (a) and (b) are the Raman spectra of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1, respectively.

[0059] Figure 1 The SEM results show that both Co@CoO-P123 and Co@CoO-F127 are granular with no significant difference in surface morphology and particle size of about 10-20 nm. Figure 1 The EDS results show that the four elements C, Co, N and O are uniformly distributed in Co@CoO-P123 and Co@CoO-F127.

[0060] Depend on Figure 2TEM images show that for Co@CoO-P123 and Co@CoO-F127, the metal particles are completely encapsulated in the carbon layer, forming a confined core-shell structure with the metal particles as the core and the nitrogen-doped carbon layer as the shell. According to crystal plane theory, the relationship between the corresponding 2θ degree in XRD and the corresponding crystal plane and interplanar spacing can be analyzed. The surface interplanar spacings of 0.25nm, 0.22nm, and 0.32nm were detected for Co@CoO-P123 and Co@CoO-F127, corresponding to the CoO (1 1 1) crystal plane, Co (11 1) crystal plane, and graphitic carbon (0 0 2) crystal plane, respectively.

[0061] Depend on Figure 3 As shown in Figures (a) and (b), Co@CoO-P123 and Co@CoO-F127 are both typical mesoporous materials with a pore size of about 5 nm. Compared with Co@CoO-P123, Co@CoO-F127 has a larger specific surface area (381.0406 m 2 / g). By Figure 3 Figure (c) shows that the positions of the diffraction peaks of Co@CoO-P123 and Co@CoO-F127 are consistent with those of CoO (PDF#78-0431) and Co (PDF#15-0806). The characteristic diffraction peaks at 2θ=42.632°, 49.673°, 72.828°, 88.226°, 93.276°, 51.830°, 60.623° and 91.083° correspond to the (1 1 1), (2 0 0), (2 2 0), (31 1) and (2 2 2) crystal planes of CoO and the (1 1 1), (2 0 0) and (2 2 0) crystal planes of Co, respectively. Figure 3 As shown in Figure (d), the functional groups contained in Co@CoO-P123 and Co@CoO-F127 include CH, CO, C=NC and NH. Since the hydrophilic segment of F127 is longer than that of P123, the vibration of the CH bond and NH bond of Co@CoO-F127 is stronger than that of Co@CoO-P123.

[0062] Depend on Figure 4 As shown in Figure (a), Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 mainly contain four elements: C, O, N, and Co. The nitrogen content of the two is 1.05wt% and 1.71wt%, respectively. Figure 4As shown in Figure (b), the corrosion potential of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 is higher than that of Co and CoO alone, indicating that the electron transfer ability of Co@CoO-P123 and Co@CoO-F127 is stronger than that of Co and CoO, which can be attributed to the electronic interaction between Co and CoO in Co@CoO-P123 and Co@CoO-F127.

[0063] Depend on Figure 5 It can be seen that the Raman spectra of Co@CoO-P123 and Co@CoO-F127 are at 1580 cm -1 and 1350cm -1 The graphitized carbon peak and disordered carbon peak appear at the center, and the I D / I G The values ​​are 1.85 and 0.98, respectively, indicating that Co@CoO-P123 has a higher degree of defects.

[0064] Inductively coupled plasma emission spectroscopy (ICP) tests revealed that the Co contents in Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 were 22.4 wt% and 18.6 wt%, respectively, indicating that a higher metal loading can be achieved by the method of the present invention.

[0065] Example 3

[0066] In this example, the ability of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 to activate PAA to degrade the pollutant naproxen (NAP) was investigated.

[0067] (1) NAP was prepared into a 10 μmol / L solution using deionized water as simulated wastewater. PAA and carbon-confined materials (Co@CoO-P123 or Co@CoO-F127) were added to the simulated wastewater. The simulated wastewater was treated at 25±1°C for 10 min under stirring conditions. The pH value of the simulated wastewater was controlled to 6.3, the amount of PAA added to the simulated wastewater was controlled to 0.2 mmol / L, and the amount of carbon-confined materials added to the simulated wastewater was controlled to 0.015 g / L.

[0068] During the treatment of simulated wastewater, samples were taken at regular intervals and filtered through a membrane. Sodium thiosulfate was added to terminate the reaction, and the NAP concentration [NAP] was then determined by liquid chromatography (HPLC). The initial NAP concentration was recorded as [NAP]0, and the change of [NAP] / [NAP]0 over treatment time was calculated, and the reaction rate constant was calculated. The results are shown in Figure 2. Figure 6 The data for the Co-P123 and Co-F127 groups are shown in Figure (a).

[0069] (2) Determine the amount of Co leached from the sample taken in step (1) using atomic absorption spectroscopy. 2+ The concentration of leached Co 2+ The concentration of Co 2+ To activate PAA to degrade NAP, the operation is the same as step (1), except that the carbon confinement material in step (1) is replaced by the above concentration of Co 2+ .

[0070] During the simulated wastewater treatment process, samples were taken at regular intervals and filtered through a 0.22 μm filter membrane. Sodium thiosulfate was added to terminate the reaction, and then the NAP concentration [NAP] was determined by HPLC. The initial NAP concentration was recorded as [NAP]0, and the change of [NAP] / [NAP]0 with treatment time was calculated. The results are shown in the figure below. Figure 6 (a) Learning Co 2+ Group data shown.

[0071] Depend on Figure 6 As shown in Figure (a), the Co leached during the degradation of NAP by PAA activated by Co@CoO-P123 or Co@CoO-F127 2+ It has almost no contribution to the degradation of NAP. After PAA activation, Co@CoO-P123 and Co@CoO-F127 can achieve 100% degradation of NAP within 10 min. The corresponding reaction rate constant k obs They are 0.5738 and 0.3218 respectively.

[0072] Example 4

[0073] In this example, the ability of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 to activate PAA to degrade different organic pollutants was investigated.

[0074] Phenol (PE), bisphenol A (BPA), sulfamethoxazole (SMX), sulfamethoxazole (SMZ), 4-chlorophenol (4-CP) and ampicillin (AMP) were prepared into solutions with a concentration of 10 μmol / L using deionized water as simulated wastewater.

[0075] The PAA and carbon confinement material (Co@CoO-P123 or Co@CoO-F127) were added to each simulated wastewater, and the simulated wastewater was treated for 10 min under stirring at 25±1°C, the pH value of the simulated wastewater was controlled to be 6.3, the addition amount of PAA in the simulated wastewater was controlled to be 0.2 mmol / L, and the addition amount of the carbon confinement material in the simulated wastewater was controlled to be 0.015 g / L. After the treatment of the simulated wastewater was completed, the sample was filtered by a filter membrane, sodium thiosulfate was added to terminate the reaction, and then the concentration C of the pollutant was determined by HPLC. The initial concentration of the pollutant was recorded as C0, and C / C0was calculated, and the results are shown in Figure 6 (b) of FIG. 1.

[0076] It can be known from Figure 6 (b) of FIG. 1 that the Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 can achieve the degradation of PE, BPA, SMX, SMZ, 4-CP and AMP, especially the degradation of SMX, SMZ and AMP. It is shown that the Co@CoO-P123 and Co@CoO-F127 have good degradation efficiency on various micropollutants and have wide applicability.

[0077] Example 5

[0078] In this example, the influence of the concentration of NAP on the degradation of NAP by the PAA activated by the Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 was investigated.

[0079] The NAP was prepared into solutions with concentrations of 10, 25 and 50 μmol / L by deionized water as simulated wastewaters. The PAA and carbon confinement material (Co@CoO-P123 or Co@CoO-F127) were added to each simulated wastewater, and the simulated wastewater was treated for 10 min under stirring at 25±1°C, the pH value of the simulated wastewater was controlled to be 6.3, the addition amount of PAA in the simulated wastewater was controlled to be 0.2 mmol / L, and the addition amount of the carbon confinement material in the simulated wastewater was controlled to be 0.015 g / L. During the treatment of the simulated wastewater, the sample was filtered by a filter membrane every certain time, sodium thiosulfate was added to terminate the reaction, and then the concentration [NAP] of NAP was determined by HPLC. The initial concentration of NAP was recorded as [NAP]0, and the change of [NAP] / [NAP]0with the treatment time was calculated, and the change of [NAP] / [NAP]0with the treatment time is shown in Figure 6 (c) of FIG. 1.

[0080] It can be known from Figure 6As shown in Figure (c), when the NAP concentration increases from 10 μmol / L to 50 μmol / L, the reaction rate decreases to a certain extent. However, after extending the reaction time, both Co@CoO-P123 and Co@CoO-F127 can activate PAA to achieve 100% removal of high-concentration NAP. This is mainly due to the fact that the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system can continuously produce multiple active species.

[0081] Example 6

[0082] In this example, the ability of Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 to activate PAA to degrade pollutants in actual water bodies was investigated.

[0083] Sulfamethoxazole (SMX) was prepared into a 10 μmol / L solution using the secondary effluent from the sewage treatment plant as a solvent, and this solution was used as the wastewater to be treated. PAA and carbon-confined materials (Co@CoO-P123 or Co@CoO-F127) were added to the wastewater to be treated, and the wastewater was treated for 10 minutes under stirring conditions at 25±1°C. The amount of PAA added to the simulated wastewater was controlled to be 0.2 mmol / L, and the amount of carbon-confined materials added to the wastewater was controlled to be 0.015 g / L. During the wastewater treatment process, samples were taken at regular intervals and filtered using a filter membrane. Sodium thiosulfate was added to terminate the reaction, and the concentration of SMX was then determined by HPLC, recorded as [SMX]. The initial concentration of SMX was recorded as [SMX]0, and [SMX] / [SMX] was calculated. 0。 The change of [SMX] / [SMX]0 with processing time is as follows Figure 6 As shown in Figure (d).

[0084] Depend on Figure 6 As can be seen from Figure (d), the degradation efficiency of the pollutant SMX in the secondary effluent was not affected. Both the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system were able to achieve 100% degradation of SMX in the secondary effluent within 5 minutes, indicating that the Co@CoO-P123 and Co@CoO-F127 activated PAA degradation system for micropollutants has good resistance to environmental interference and has good application potential in actual complex water matrices.

[0085] Example 7

[0086] In this example, the effect of PAA concentration on the activation of PAA by Co@CoO-P123 prepared in Example 1 to degrade NAP was investigated.

[0087] NAP was prepared into a solution with a concentration of 10 μmol / L by using deionized water as simulated wastewater. PAA and Co@CoO-P123 were added into the simulated wastewater, and the simulated wastewater was treated under stirring at 25±1℃ for 10 min, the pH value of the simulated wastewater was controlled to be 6.3, and the adding amount of the carbon-limited material in the simulated wastewater was controlled to be 0.015 g / L. This embodiment was divided into 4 groups of experiments, the concentration of PAA was different in each group of experiments, and other conditions were the same, and the concentration of PAA in the simulated wastewater was controlled to be 50, 100, 200 and 400 μmol / L respectively in each group of experiments.

[0088] During the treatment of the simulated wastewater, samples were taken every certain time for filtration by using a filter membrane, sodium thiosulfate was added to terminate the reaction, then HPLC was used to determine the concentration of NAP, and the reaction rate constant was calculated, and the results are shown in the (a) graph of FIG. Figure 7

[0089] As can be seen from the (a) graph of FIG. Figure 7 , under the condition that other experimental conditions are unchanged, with the increase of the concentration of PAA, the removal rate of NAP also increases, but with the further increase of the concentration of PAA, the removal rate of NAP decreases, when the concentration of PAA in the simulated wastewater is 50, 100, 200 and 400 μmol / L, the reaction rate constant is 0.2082, 0.3507, 0.5739 and 0.4981 min -1 respectively. Considering the removal rate of pollutants and the cost of wastewater treatment comprehensively, when the adding amount of the catalyst in the wastewater is about 0.015 g / L, the adding amount of PAA in the wastewater between 50 and 400 μmol / L is feasible.

[0090] Example 8

[0091] In this embodiment, the influence of the adding amount of Co@CoO-P123 on the degradation of NAP by PAA activated by Co@CoO-P123 was investigated.

[0092] NAP was prepared into a solution with a concentration of 10 μmol / L by using deionized water as simulated wastewater. PAA and Co@CoO-P123 were added into the simulated wastewater, and the simulated wastewater was treated under stirring at 25±1℃ for 10 min, the pH value of the simulated wastewater was controlled to be 6.3, and the adding amount of the carbon-limited material in the simulated wastewater was controlled to be 0.015 g / L. This embodiment was divided into 4 groups of experiments, the concentration of PAA was different in each group of experiments, and other conditions were the same, and the concentration of PAA in the simulated wastewater was controlled to be 50, 100, 200 and 400 μmol / L respectively in each group of experiments.

[0093] ​During the treatment of simulated wastewater, samples were taken at regular intervals and filtered through a membrane. Sodium thiosulfate was added to terminate the reaction. The NAP concentration was then determined by HPLC and the reaction rate constant was calculated. The results are shown in the figure below. Figure 7 As shown in the bar graph in Figure (b), Figure 7 The curve in Figure (b) refers to the adsorption rate of NAP at different Co@CoO-P123 dosages (without adding PAA).

[0094] Depend on Figure 7 As shown in Figure (b), when other experimental conditions remain unchanged, the removal rate of NAP increases with the increase in the dosage of Co@CoO-P123, but with the further increase in the dosage of Co@CoO-P123, the adsorption rate of NAP also increases. Taking into account the pollutant removal rate and wastewater treatment cost, when the dosage of PAA in the wastewater is about 200 μmol / L, the dosage of Co@CoO-P123 in the wastewater is feasible between 0.005 and 0.3 g / L.

[0095] Example 9

[0096] In this example, PAA consumption during activation by Co@CoO-P123 and Co@CoO-F127, prepared in Example 1, was investigated. Methyl p-tolyl sulfide (MTS) was used as an indicator for residual PAA. The oxidation product of the reaction between MTS and PAA is MTSO, a sulfoxide. HPLC analysis of MTSO concentrations can be used to track PAA consumption in the system.

[0097] PAA and carbon-confined material (Co@CoO-P123 or Co@CoO-F127) were added to deionized water and reacted for 10 minutes under stirring conditions at 25±1°C. The amount of PAA added to the simulated wastewater was controlled to be 0.2 mmol / L, and the amount of carbon-confined material added to the deionized water was controlled to be 0.015 g / L. 500 μL of samples were taken at 0 min, 1 min, 3 min, 5 min, 8 min and 10 min of reaction, filtered with a filter membrane, and immediately mixed with 250 μL of a 2.0 mmol / L MTS solution prepared in advance with acetonitrile. The concentration of MTSO was then determined by HPLC. Since the reaction coefficient of PAA and MTS is 1:1, the concentration of MTSO generated is used to represent the concentration of PAA consumed. The results are as follows: Figure 8 shown.

[0098] At 10 min, the concentrations of MTSO generated in the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system were 98.12 μmol / L and 87.78 μmol / L, respectively. That is, the amount of PAA consumed by the two systems was only 98.12 μmol / L and 87.78 μmol / L, indicating that the two systems have a high utilization efficiency of PAA in degrading pollutants.

[0099] Example 10

[0100] In this example, the durability of PAA activation and NAP degradation by Co@CoO-P123 and Co@CoO-F127 prepared in Example 1 was investigated.

[0101] NAP was prepared into a solution with a concentration of 10 μmol / L using deionized water as simulated wastewater. In the first reaction, PAA and carbon-confined material (Co@CoO-P123 or Co@CoO-F127) were first added to the simulated wastewater. The simulated wastewater was treated for 15 minutes under stirring conditions at 25±1°C. The pH value of the simulated wastewater was controlled to 6.3, the amount of PAA added to the simulated wastewater was controlled to 0.2 mmol / L, and the amount of carbon-confined material added to the simulated wastewater was controlled to 0.015 g / L.

[0102] After the first reaction, a freshly prepared NAP solution was added directly to the wastewater to bring the NAP concentration to 10 μmol / L. A second reaction was initiated without the addition of PAA or carbon-confined materials. Similarly, after the second reaction, a freshly prepared NAP solution was added directly to the wastewater to bring the NAP concentration to 10 μmol / L. This cycle was repeated 4-5 times.

[0103] During the entire simulated wastewater treatment process, samples were taken at regular intervals and filtered through a membrane. Sodium thiosulfate was added to terminate the reaction, and the NAP concentration [NAP] was then determined by HPLC. The initial NAP concentration was recorded as [NAP]0, and the change of [NAP] / [NAP]0 with treatment time was calculated. The results are shown in the figure below. Figure 9 As shown in Figure (a).

[0104] Depend on Figure 9Figure (a) shows that after the first reaction, the Co@CoO-P123 / PAA system completely degrades the second NAP addition without the addition of the oxidant PAA or carbon-confined materials, and efficiently degrades the third NAP addition, achieving a removal rate exceeding 80%. Similarly, the Co@CoO-F127 / PAA system completely degrades the second NAP addition without the addition of the oxidant PAA or carbon-confined materials, achieving a removal rate exceeding 90% for the third NAP addition and approximately 50% for the fourth NAP addition. These experimental results demonstrate that both the Co@CoO-P123 / PAA and Co@CoO-F127 / PAA systems can achieve sustained generation and existence of active species over an extended period, thereby enabling sustained degradation of pollutants.

[0105] Example 11

[0106] In this example, the stability of PAA degradation using Co@CoO-P123 and Co@CoO-F127, prepared in Example 1, was investigated. A continuous flow system was used to evaluate the stability of the Co@CoO-P123 / PAA and Co@CoO-F127 / PAA systems in pollutant degradation over an extended period.

[0107] NAP was prepared into a solution with a concentration of 10 μmol / L using deionized water, and PAA was added to the NAP solution until the concentration of PAA was 0.2 mmol / L to form a NAP / PAA mixed solution. 50 mg of carbon-confined material (Co@CoO-P123 or Co@CoO-F127) was fixed in the reaction column using cotton as a carrier. Flexible hoses were connected to the inlet and outlet of the reaction column, and the NAP / PAA mixed solution was continuously passed into the reaction column from the inlet by a peristaltic pump at a flow rate of 0.8 to 1.5 mL / min, and then continuously discharged into the water outlet container from the outlet, thereby forming a continuous flow system for wastewater treatment. During the operation of the continuous flow system, samples were taken at the outlet at regular intervals and filtered with a filter membrane. Sodium thiosulfate was added to terminate the reaction, and then the NAP concentration C was determined by HPLC. The initial concentration of NAP was recorded as C0, and the change of C / C0 with treatment time was calculated. The results are shown in the figure. Figure 9 (b) shown.

[0108] Depend on Figure 9(b)As shown, both Co@CoO-P123 / PAA system and Co@CoO-F127 / PAA system can achieve complete removal of NAP within the first 60h of continuous flow system operation, and the removal rate of NAP can still reach more than 60% after 120h of continuous flow system operation. This shows that Co@CoO-P123 / PAA system and Co@CoO-F127 / PAA system can achieve long-term stable operation in the continuous flow system, further confirming that the carbon confined material described in the application has the characteristics of high efficiency, stability and sustainability, and has potential for practical application.

[0109] Example 12

[0110] In this embodiment, various experiments are used to explore the types and reaction pathways of active oxidative species generated by Co@CoO-P123 / PAA system and Co@CoO-F127 / PAA system when degrading NAP in wastewater.

[0111] 1. Quenching experiment

[0112] The quenching agents used include methanol (MeOH), 2,4-hexadiene (2,4-HD), tert-butyl alcohol (TBA) and dimethyl sulfoxide (DMSO), wherein MeOH and 2,4-HD can simultaneously quench hydroxyl radicals (·OH) and organic free radicals (RO·), TBA can only quench ·OH, and DMSO can quench singlet oxygen ( 1 O2).

[0113] NAP was prepared into a solution with a concentration of 10 μmol / L using deionized water as simulated wastewater. PAA and carbon confined material (Co@CoO-P123 or Co@CoO-F127) prepared in Example 1 were added to the simulated wastewater, and the simulated wastewater was treated under stirring at 25±1℃ for 10 min. The pH value of the simulated wastewater was controlled at 6.3, the addition amount of PAA in the simulated wastewater was controlled at 0.2 mmol / L, and the addition amount of carbon confined material in the simulated wastewater was controlled at 0.015 g / L. Different concentrations and types of quenching agents were added to the simulated wastewater before the reaction started, as follows:

[0114] Control group: no quenching agent was added;

[0115] MeOH group: MeOH was added to the simulated wastewater to a concentration of 100 mmol / L;

[0116] TBA group: TBA was added to the simulated wastewater to a concentration of 100 mmol / L;

[0117] 2,4-HD group: 2,4-HD was added to the simulated wastewater to a concentration of 5 mmol / L;

[0118] DMSO group: DMSO was added to the simulated wastewater until the concentration of DMSO reached 10 mmol / L;

[0119] During the simulated wastewater treatment process, samples were taken at 0 min, 1 min, 3 min, 5 min, 8 min and 10 min after treatment, and filtered with a membrane. Sodium thiosulfate was added to terminate the reaction, and then the NAP concentration was determined by HPLC to calculate the reaction rate constant k. obs .

[0120] After adding the corresponding quencher, the higher the degree of inhibition on the degradation of pollutants, the greater the contribution of the active species quenched by the corresponding quencher to the degradation of pollutants (excluding the solvent effect and the consumption of PAA itself by the quencher). Figure 10 As shown in the figure, when 100mmol / L TBA is added, the degradation of NAP by the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system is slightly inhibited, especially the Co@CoO-F127 / PAA system, indicating that the contribution of ·OH in the two catalytic systems is relatively weak. When 100mmol / L MeOH and 5mmol / L 2,4-HD are added, the degree of inhibition of the degradation of NAP by the two systems is significantly higher than that of the experimental group with TBA, indicating that RO· in the two systems plays a role in the degradation of NAP. At the same time, the addition of DMSO greatly inhibits the degradation of NAP by the two systems, indicating that the two systems 1 O2 also plays an important role in the degradation of NAP. The quenching experiment results show that ·OH, RO· and 1 O2, these active species.

[0121] 2. Electron paramagnetic resonance (EPR) detection

[0122] By combining with a spin trap, EPR can capture the characteristic peaks formed by free radicals and the trap, thereby qualitatively determining different active species. When 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) is used as a trap, EPR can capture the adduct signal peak of DMPO-OH with a peak shape of 1:2:2:1, thereby confirming the presence of ·OH; when 2,2,6,6-tetramethylpiperidine (TEMP) is used as a trap, if there is 1 In the presence of O2, tetramethylpiperidinyl oxide (TEMPO) is generated, and a 1:1:1 triplet peak is detected by EPR.

[0123] A capture agent (DMPO or TEMP) was added to a sampling tube containing 2 mL of deionized water to a concentration of 100 mmol / L. PAA and the carbon-confined material (Co@CoO-P123 or Co@CoO-F127) prepared in Example 1 were then added to initiate the reaction. During the reaction, samples were drawn with a capillary at regular intervals and detected by EPR. The concentration of PAA in water was controlled to be 1 mmol / L, and the amount of carbon-confined material added to water was controlled to be 0.075 g / L. The test results are shown in FIG. Figure 11 shown.

[0124] like Figure 11 As shown in Figures (a) and (b), the 1:2:2:1 DMPO-OH adduct signal peak was detected in both the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system during the reaction, and the signal peak showed a trend of continuous strengthening with the extension of the reaction time. This strengthening trend lasted for 90 to 120 minutes, indicating that ·OH was formed in both systems. At the same time, the ·OH signal peak of the Co@CoO-P123 / PAA system was stronger than that of the Co@CoO-F127 / PAA system. The experimental results show that the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system have continuous ·OH generation and existence for a long time during the reaction, which may be the reason for inducing the continuous degradation of NAP in Example 11. In addition, compared with the Co@CoO-P123 / PAA system, the Co@CoO-F127 / PAA system produces less ·OH, which is consistent with the inhibition results of TBA in the above quenching experiment. like Figure 11 As shown in Figures (c) and (d), a strong 1:1:1 signal peak was detected in both the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system, and the signal also increased with the extension of the reaction time, indicating that there is 1 The continuous generation and existence of O2.

[0125] 3. Probe Experiment

[0126] Benzoic acid (BA) can selectively react with ·OH, leading to degradation. Coumarin can also react with ·OH to form 7-hydroxycoumarin. Therefore, the formation of ·OH in the system can be investigated by reacting BA and coumarin with ·OH and then measuring the residual BA and the formation of 7-hydroxycoumarin using HPLC. High-valent metals react with methyl phenyl sulfoxide (PMSO) to form methyl phenyl sulfone (PMSO2) through double electron transfer. Therefore, the formation of Co(IV) in the system can be determined by measuring the conversion of PMSO to PMSO2.

[0127] (1) OH probe experiment

[0128] BA and coumarin were prepared into 10 μmol / L and 2 mmol / L solutions respectively with deionized water as probes. PAA and the carbon confined material (Co@CoO-P123 or Co@CoO-F127) prepared in Example 1 were added to the probe solution and reacted for 120 minutes under stirring. The amount of PAA added to the probe solution was controlled to be 0.2 mmol / L, and the amount of carbon confined material added to the probe solution was controlled to be 15 mg / L. During the probe experiment, samples were taken at regular intervals and filtered through a filter membrane. Na2S2O3 was added to quench the reaction. The concentrations of BA and 7-hydroxycoumarin were detected by HPLC, and the results were as follows. Figure 12 As shown in Figures (A) and (B).

[0129] Depend on Figure 12 It can be seen that during the 2-h reaction process, BA showed a trend of continuous degradation, and the concentration of 7-hydroxycoumarin showed a trend of continuous increase. The two experimental results jointly showed that during the reaction process of the Co@CoO-P123 / PAA system and the Co@CoO-F127 / PAA system, ·OH had a trend of continuous generation, which further confirmed the conclusion of the EPR detection.

[0130] (2) Co(IV) probe experiment

[0131] PMSO was prepared into a 250 μmol / L solution with deionized water as a probe. PAA and the carbon-confined material (Co@CoO-P123 or Co@CoO-F127) prepared in Example 1 were added to the probe solution and reacted for 120 minutes under stirring. The amount of PAA added to the probe solution was 0.2 mmol / L, and the amount of carbon-confined material added to the probe solution was controlled to be 15 mg / L. During the probe experiment, samples were taken at regular intervals and filtered through a filter membrane. Na2S2O3 was added to quench the reaction. The residual concentration of PMSO and the generated concentration of PMSO2 were detected by HPLC. The results are shown in Figure 2. Figure 13 As shown in Figures (A) and (B).

[0132] Depend on Figure 13 During the reaction, PMSO in both the Co@CoO-P123 / PAA and Co@CoO-F127 / PAA systems was continuously consumed, while PMSO2 was continuously generated, with the sum of PMSO and PMSO2 approaching a plateau. Furthermore, the PMSO-PMSO2 conversion rate approached 100%, indicating the presence of Co(IV) in both systems, with Co(IV) primarily generated within the first 60 minutes of the reaction.

[0133] (3) R-O· probe

[0134] 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO) can capture RO· (CH3COO· or CH3·) to generate more stable CH3COO·-TEMPO or CH3·-TEMPO, which can be detected by high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS / MS), further illustrating the generation of RO· in the system.

[0135] TEMPO was prepared into a 5 mmol / L solution with deionized water as a probe. PAA and carbon-encapsulated materials (Co@CoO-P123 or Co@CoO-F127) prepared in Example 1 were added to the probe solution, and the reaction was carried out under stirring for 10 min. The amount of PAA added to the probe solution was controlled to be 0.2 mmol / L, and the amount of carbon-encapsulated material added to the probe solution was controlled to be 15 mg / L. After the reaction was completed, the sample was detected by UPLC-QTOF-MS / MS, and the results are shown in Figure 14

[0136] As shown in Figure 14 , in the Co@CoO-P123 / PAA system, CH3·-TEMPO and CH3COO·-TEMPO adduct signal peaks with m / z of 172.1696 and 216.1594 were detected, indicating that CH3· and CH3COO· were generated in the system. In the Co@CoO-F127 / PAA system, CH3COO·-TEMPO adduct signal peak with m / z of 216.1594 was detected, indicating that CH3COO· was generated in the system.

[0137] Example 13

[0138] In this example, carbon-encapsulated materials (nitrogen-doped encapsulated Co@CoO core-shell materials) were prepared and used to activate PAA to degrade NAP, and the steps were as follows:

[0139] (1) Dopamine hydrochloride and block copolymer were added to an ethanol-water solution, so that the concentration of dopamine hydrochloride and block copolymer in the ethanol-water solution was 8 g / L and 12 g / L, respectively. The mixture was ultrasonically treated until all components were fully dissolved to obtain block copolymer-dopamine hydrochloride micelles. Cobalt nitrate hexahydrate was added to the block copolymer-dopamine hydrochloride micelles to a concentration of 4 mmol / L, and then 1,3,5-trimethylbenzene and ammonia water were rapidly added in sequence at a stirring speed of 500 rpm / min. After continuous stirring for 60 min, the stirring speed was adjusted to 300 rpm / min, and the stirring was continued for 4 h. The obtained mixture was centrifuged, and the obtained solid particles were washed with ethanol and deionized water for multiple times. The solid particles were collected and dried. ​

[0140] In this step, the ethanol-water solution is prepared by mixing deionized water and anhydrous ethanol at a volume ratio of 2:3, and 1,3,5-trimethylbenzene and ammonia water are added at a volume ratio of 1.2:100 and 2:100 with respect to the ethanol-water solution. The block copolymer used is Pluronic F108.F124

[0141] (2) The dried solid particles are heated to 360°C at a heating rate of 2°C / min under N2 atmosphere, and then heated to 900°C at a heating rate of 2°C / min, and kept for 1 h to obtain nitrogen-doped confined Co@CoO core-shell material, denoted as Co@CoO-F108.

[0142] (3) The NAP is prepared into a solution with a concentration of 10 μmol / L using deionized water as the simulated wastewater, and PAA and Co@CoO-F108 are added to the simulated wastewater. The simulated wastewater is treated for 10 min under stirring at 25±1°C, the pH value of the simulated wastewater is controlled at 6.3, the addition amount of PAA in the simulated wastewater is controlled at 0.2 mmol / L, and the addition amount of Co@CoO-F108 in the simulated wastewater is controlled at 0.02 g / L.

[0143] During the treatment of the simulated wastewater, samples are taken every certain period of time, filtered with a filter membrane, and terminated by adding sodium thiosulfate, and then the concentration of NAP is determined by HPLC and the removal rate of NAP is calculated, and the result is 100%.

[0144] Example 14

[0145] In this example, a carbon-confined material (nitrogen-doped confined Co@CoO core-shell material) is prepared, and PAA is activated by the carbon-confined material to degrade NAP, and the steps are as follows:

[0146] (1) Dopamine hydrochloride and a block copolymer are added to an ethanol-water solution, so that the concentration of dopamine hydrochloride and the block copolymer in the ethanol-water solution is 4 g / L and 12 g / L, respectively, and the block copolymer-dopamine hydrochloride micelles are obtained by ultrasonic treatment until the components are fully dissolved. Cobalt nitrate hexahydrate is added to the block copolymer-dopamine hydrochloride micelles to a concentration of 3 mmol / L, and then 1,3,5-trimethylbenzene and ammonia water are rapidly added in sequence at a rotation speed of 500 rpm / min, and the rotation speed is adjusted to 300 rpm / min after stirring for 30 min, and the stirring is continued for 2.5 h. The obtained mixture is centrifuged, and the obtained solid particles are washed with ethanol and deionized water for multiple times, and the solid particles are collected and dried.

[0147] In this step, the ethanol-water solution is prepared by mixing deionized water and anhydrous ethanol at a volume ratio of 2:3, and 1,3,5-trimethylbenzene and ammonia water are added at a volume ratio of 1:100 and 1:100 with respect to the ethanol-water solution. The block copolymer used is F124.

[0148] (2) The dried solid particles are heated to 340°C at a heating rate of 2°C / min under N2 atmosphere, and then heated to 800°C at a heating rate of 2°C / min, and kept for 3h to obtain nitrogen-doped confined Co@CoO core-shell material, denoted as Co@CoO-F124.

[0149] (3) The NAP is prepared into a solution with a concentration of 10 μmol / L using deionized water as simulated wastewater, and PAA and Co@CoO-F124 are added to the simulated wastewater. The simulated wastewater is treated for 8 min under stirring at 25±1°C, the pH value of the simulated wastewater is controlled at 6.3, the addition amount of PAA in the simulated wastewater is controlled at 0.3 mmol / L, and the addition amount of Co@CoO-F124 in the simulated wastewater is controlled at 0.025 g / L.

[0150] During the treatment of the simulated wastewater, samples are taken every certain period of time, filtered with a filter membrane, and sodium thiosulfate is added to terminate the reaction. Subsequently, the concentration of NAP is determined by HPLC, and the removal rate of NAP is calculated. The result is 100%.

Claims

1. A method for achieving sustained degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials, characterized in that: The following steps are involved: adding peracetic acid and a carbon-confined material to wastewater containing organic pollutants, and treating the wastewater under stirring conditions, wherein during the wastewater treatment process, the carbon-confined material activates the peracetic acid to generate hydroxyl radicals, organic free radicals, singlet oxygen, and Co(IV) to degrade the organic pollutants in the wastewater; The carbon confined material is composed of a cobalt material and a nitrogen-doped carbon material coated with the cobalt material, wherein the cobalt material is composed of Co and CoO. The carbon confined material is a nanoparticle with a core-shell structure. The preparation method of the carbon confined material is as follows: (1) Dopamine hydrochloride and block copolymer are added to an ethanol-water solution, and ultrasonic treatment is performed to form block copolymer-dopamine hydrochloride micelles. A water-soluble cobalt salt is added to the block copolymer-dopamine hydrochloride micelles, and after thorough mixing, 1,3,5-trimethylbenzene and ammonia water are added. The mixture is stirred for 3-5 hours, and the solid-liquid separation is performed, and the solid phase is washed; In this step, dopamine hydrochloride and the block copolymer are added to an ethanol-water solution at a mass ratio of 1:(1.5-3), the concentration of dopamine hydrochloride in the ethanol-water solution is controlled to be 4-8 g / L, the concentration of the water-soluble cobalt salt in the block copolymer-dopamine hydrochloride micelles is controlled to be 2-4 mmol / L, and 1,3,5-trimethylbenzene and ammonia water are added at a volume ratio of (0.9-1.2):100 and (1-2):100 to the ethanol-water solution; the volume content of ethanol in the ethanol-water solution is 50%-60%. (2) The solid phase obtained in step (1) is heated to 340-360°C under a N2 atmosphere and kept warm for 2-4 h, then heated to 800-900°C and kept warm for 1-3 h.

2. The method for achieving continuous degradation of pollutants at low dosage based on self-assembly induced carbon confined materials according to claim 1, characterized in that: The cobalt content in the carbon confined material is 18 wt% to 23 wt%, and the nitrogen content is 1.0 wt% to 2.4 wt%.

3. The method for achieving sustained degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials according to claim 1, characterized in that: In the nitrogen-doped carbon material, the carbon phase composition is graphitized carbon and disordered carbon, and the intensity ratio of the D band to the G band in the Raman spectrum of the nitrogen-doped carbon material is 0.98-1.

85.

4. The method for achieving sustained degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials according to claim 1, characterized in that: The particle size of the carbon confined material is 10-20 nm, and the carbon confined material has a mesoporous structure with an average pore size not exceeding 10 nm.

5. The method for achieving sustained degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials according to claim 1, characterized in that: The block copolymer is polyethylene oxide-block-polypropylene oxide-block-polyethylene oxide, or polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol.

6. The method for achieving sustained degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials according to any one of claims 1 to 4, characterized in that: The dosage of peracetic acid in wastewater was controlled at 50~400 µmol / L.

7. The method for achieving sustained degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials according to any one of claims 1 to 4, characterized in that: The dosage of carbon confinement material in wastewater is controlled to be 5~50 mg / L.

8. The method for achieving sustained degradation of pollutants at low dosage based on self-assembly-induced carbon confined materials according to any one of claims 1 to 4, characterized in that: The wastewater treatment time is controlled to be 10~120 min.

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