CN117358223A - Preparation and application of oxygen modified carbon catalyst with adjustable surface carbon base number - Google Patents

Abstract

The invention discloses the preparation and application of an oxygen-modified carbon catalyst with an adjustable number of surface carbon groups. The catalyst is prepared by using Ketjen black as the carbon substrate and ethylenediaminetetraacetic acid as the oxygen source through stepwise oxygenation (including surface oxidation and pyrolysis of the oxygen-containing precursor) to modify the oxygen onto the carbon substrate. The target catalyst is obtained; the number (concentration) of carbonyl groups at the activated persulfate site on the catalyst surface can be controlled by regulating the pyrolysis temperature or using surface modification with glutaraldehyde or/dansyl hydrazide. This concentration change will cause the electron distribution between adjacent carbonyl groups, that is, the site spacing effect; using this effect, efficient purification of water polluted by organic pollutants and effective soil remediation can be achieved.

Description

Preparation and application of an oxygen-modified carbon catalyst with an adjustable number of surface carbon groups

Technical field

The invention belongs to the technical field of catalysts, and specifically relates to an oxygen-modified carbon catalyst with an adjustable number of surface carbon groups and its application in activating persulfate to remove organic pollutants in environmental water bodies.

Background technique

As one of the advanced oxidation technologies, the persulfate activation process has extensive and profound applications in the fields of environmental water management, in-situ soil remediation, animal tumor treatment, and chemical synthesis due to its ability to release strong oxidizing species. The active species released by this process include strongly oxidizing free radicals, such as sulfate radicals (SO ₄ ^·- , 2.5-3.1V _NHE ), hydroxyl radicals ( ^· OH, 1.8-2.7V _NHE ) and even super Oxygen anion radical (O ₂ ^·- , -0.28V _NHE ). As far as environmental water body remediation is concerned, these free radicals show good degradation and mineralization capabilities of water body organic pollutants, especially in laboratory-scale water body treatment experiments. However, in actual engineering applications of water or soil remediation, the strongly oxidizing free radical species released by this technology are often difficult to effectively remove organic pollutants. This is due to the fact that in actual media, such as water, the water quality conditions are different (such as variable pH) and the composition is complex, such as containing different natural organic matter and inorganic anions. Therefore, it is very necessary and urgent to induce the precipitation of highly efficient active species in the process to selectively degrade organic pollutants and avoid interference from complex components in the water body.

The above-mentioned active species that can efficiently and selectively degrade organic pollutants include non-radical singlet oxygen ( ¹ O ₂ , 2.2V _NHE ), electron transfer processes, and high-valent metal oxidation. The distinguishing features of this process are the mildness of the reaction and the selective degradation of target organic compounds. This increases the greenness of the water or soil media remediation process and avoids the reduction of reaction costs due to excessive oxidation of the catalyst. According to the needs of actual water treatment, the core step in an effective way to induce active species generated during persulfate activation on demand lies in the rational design of the catalyst. It has been widely reported that metal-based catalysts exhibit difficulty in recycling the metal valence state when activating persulfate to remediate water bodies, resulting in easy deactivation and easy dissolution of the metal catalytic sites. Not only does it have high catalyst preparation costs but it also increases possible secondary pollution. Accordingly, non-metallic catalysts represented by carbon-based catalysts show attractive application prospects. This catalyst can not only overcome the shortcomings of metal-based catalysts, but also has unique advantages, such as low price, adjustable electronic structure, and the ability to still effectively catalyze acidic or alkaline media. Common modification methods for carbon-based catalysts include modification of boron, nitrogen, sulfur or phosphorus elements to change the in-plane electronic structure and activate the inert carbon substrate. These modified elements often constitute catalytic sites on the carbon substrate that activate persulfate. However, so far, there are few reports on the use of oxygen-modified carbon substrates to construct active sites for activated persulfate, and there are no reports on the effect of the spacing effect of the catalytic site (i.e., the distance between adjacent catalytic sites) on the removal of activated persulfate. Effects of organic pollutants in water bodies.

Contents of the invention

The object of the present invention is to provide an oxygen-modified carbon catalyst, a method for quantitatively adjusting the carbonyl group on the surface of the catalyst, and its application in activating persulfate to remove organic pollutants.

In order to achieve the above objects, the present invention adopts the following technical solutions:

An oxygen-modified carbon catalyst is prepared using the following steps:

Step 1: Use nitric acid solution to surface oxidize Ketjen Black;

Step 2: Disperse the oxidized Ketjen Black in deionized water, then add the oxygen source ethylenediaminetetraacetic acid and the active agent dicyandiamide in sequence, mix evenly, dry the mixture, grind and perform pyrolysis under an inert gas atmosphere. An oxygen-modified carbon catalyst is obtained.

Further, in step 1, add 80 mL of 6M nitric acid solution for every 200 mg of Ketjen Black.

Further, the conditions for surface oxidation in step 1 are 50 to 100°C and 6 to 24 hours.

Further, in step 2, every 30 mg of oxidized Ketjen Black was dispersed in 3 mL of deionized water, and then 2.05 g of ethylenediaminetetraacetic acid and 8 g of dicyandiamide were added in sequence.

Further, the pyrolysis conditions in step 2 are 650-900°C and 1-3 hours.

Furthermore, glutaraldehyde or dansyl hydrazide is used to modify the oxygen-modified carbon catalyst to control the number of carboxyl groups distributed on the surface of the catalyst.

Application of the above oxygen-modified carbon catalyst in activating persulfate.

Application of the above-mentioned oxygen-modified carbon catalyst in catalytically degrading organic pollutants in water and/or soil.

Further, the oxygen-modified carbon catalyst is used to catalyze persulfate degradation of organic pollutants in water and/or soil.

In a specific embodiment of the invention, the persulfate is preferably peroxydisulfate (PDS).

Compared with the prior art, the present invention has the following beneficial effects:

(1) Use a one-step pyrolysis method to prepare non-metallic carbon-based catalysts. The preparation process is green, environmentally friendly, simple and fast. All precursors are converted into valuable catalysts, and no metal residues and other wastes are generated.

(2) It was discovered for the first time that an oxygen-modified carbon-based catalyst activates persulfate to remediate organic pollutants in water and soil. Compared with widely reported metal-based catalysts, in the repair process of the present invention, the catalyst preparation cost is low, the reaction is efficient, and there is no secondary pollution.

(3) It was discovered for the first time that the oxygen-containing functional groups at the catalytic site in persulfate activated by oxygen-modified carbon-based catalysts can be quantitatively controlled according to treatment needs. Adjusting the concentration of carbonyl groups at the catalytic site, thereby changing the site spacing effect, can regulate the efficiency of activated persulfate in removing organic pollutants.

Description of the drawings

Figure 1 shows the morphology characterization diagram and elemental analysis diagram of the prepared O/C-8.

Figure 2 shows the chemical composition analysis chart of the prepared O/C-8, including X-ray diffraction pattern and X-ray photoelectron spectrum.

Figure 3 shows the effect of the prepared O/C-8 activated common oxidants on the degradation and removal of 2,4-dichlorophenol and the bond energy analysis of common oxidants.

Figure 4 shows the effect of the prepared O/C-8 activated PDS on removing common refractory organic pollutants in water and the effect of the above process on removing 2,4-dichlorophenol in soil.

Figure 5 is a diagram showing the effect of the prepared O/C-8 activated PDS on removing the total organic carbon of 2,4-dichlorophenol in water and soil.

Figure 6 shows the chemical composition analysis and carbonyl content comparison of the oxygen element of the catalyst O/C-T prepared at different temperatures.

Figure 7 shows the effect of O/C-T catalysts prepared at different temperatures on the degradation of organic matter in furfuryl alcohol and the comparison of the carbonyl content on the catalyst and the degradation effect of furfuryl alcohol.

Figure 8 is an X-ray photoelectron spectroscopy analysis of the change in carbonyl content after O/C-8 modification.

Figure 9 shows the change in carbonyl content after O/C-8 modification analyzed by Fourier transform infrared spectroscopy.

Figure 10 is a performance diagram of the active species produced by the prepared O/C-8 activated PDS with carbonyl content and the degradation of organic matter.

Detailed ways

The invention prepares a non-metallic catalyst with oxygen modified carbon, regulates the concentration of the carbonyl group of the main catalytic functional group of the catalyst, activates persulfate to remove organic pollutants in water and soil, and is effectively used.

The preferred embodiments of the present invention will be described in detail below with reference to examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

The experimental methods used in the following examples are conventional methods unless otherwise specified.

Materials, reagents, etc. used in the following examples can all be obtained from commercial sources unless otherwise specified.

The treatment process using catalyst in the present invention is as follows:

(1) Application in water body management

① Take 10 mg of the catalyst prepared in the following examples and add it to 100 mL of sewage containing 10 mg/L organic pollutants. The organic pollutants degraded in the present invention include phenol, sulfamethoxazole, 2,4-dichlorophenol, and bisphenol. A and tetracycline, the probe molecule furfuryl alcohol.

② Stir with a magnetic stirrer for 30 minutes to achieve an adsorption-desorption equilibrium between the catalyst and organic matter.

③After that, add 5 mg of oxidant potassium peroxodisulfate PDS to induce a Fenton-like reaction to degrade and remove organic pollutants in the water.

④According to the preset time, take 0.5mL of the reaction solution, pass it through the membrane, and enter the high-performance liquid chromatography to analyze the concentration of the target organic matter to evaluate the degradation performance of the system.

(2) Application in soil remediation

①The actual soil sample comes from China Pharmaceutical University Jiangning Campus. Impurities such as leaves, weeds and stone fine particles are removed from the soil sample and passed through a 40-mesh sieve.

② The screened soil is thoroughly mixed according to a ratio of 1 mg of 2,4-dichlorophenol per gram of soil. The mixing method is to turn the soil mixer upside down for 3 hours.

③Mix the soil containing organic pollutants and the catalyst thoroughly so that each gram of soil contains 15 mg of catalyst. The mixing method is to turn the soil mixer upside down for 3 hours.

④Add 20mM peroxydisulfate (PDS) solution to the above mixture to induce a Fenton-like reaction. The amount added is 1mL per gram of soil sample, and the organic pollutants are degraded in a stirrer by turning it upside down ( The rotation speed is 80 rpm).

⑤According to the preset time, take 0.3g soil sample and 3mL of n-hexane solution containing 10% formic acid (mass fraction), ultrasonic for 1 hour, mix them thoroughly, and extract the organic pollutant 2,4-dichloride contained in the soil. phenol.

⑥The obtained extract is passed through the membrane and then enters high performance liquid chromatography to analyze the concentration of target organic matter to evaluate the degradation performance of the system.

Example 1

1. Preliminary oxidation of carbon substrate

① Add 200 mg of commercial Ketjen Black into a round-bottomed flask containing 80 mL of 6M nitric acid solution, and stir at 80°C for 12 hours through a condensation reflux device.

② Wash the above-mentioned oxidized Ketjen Black with ethanol and deionized water several times until the pH value of the washing liquid is close to neutral.

③ Dry the above-treated Ketjen Black in an oven at 60°C for 12 hours and set aside.

2. Preparation of oxygen-modified carbon catalyst

① Disperse 30 mg of oxidized Ketjen Black in 3 mL of deionized water, stir and ultrasonic for 5 minutes to disperse evenly.

② Add 2.05g of ethylenediaminetetraacetic acid to the above mixture, stir and sonicate for 10 minutes to mix evenly.

③Add 8g of dicyandiamide to the above mixture, stir and sonicate for 10 minutes to mix evenly.

④ Dry the above mixture in an oven at 60°C for 12 hours, and grind the resulting solid mixture again for 30 minutes to reduce the particle size of the material.

⑤ Pyrolyze the above-ground mixture in a tube furnace under nitrogen atmosphere protection for 2 hours, with a heating rate of 5°C/min and pyrolysis temperatures set at 650, 700, 750, 800 and 900°C. After the tube furnace is naturally cooled, the solid powder catalyst is taken out and ground again. The resulting catalyst is named O/C-T, where O represents oxygen, C represents carbon substrate, and T represents the pyrolysis temperature. For example, a sample prepared by pyrolysis at 800°C for 2 hours is named O/C-8. The content of carbonyl groups on the catalyst surface can be controlled by controlling the pyrolysis temperature.

Figure 1 shows the physical morphology and doping element characterization of catalyst O/C-8. Figure 1a is a scanning electron microscope image of the catalyst, which reflects that the catalyst exhibits a curled structure accompanied by a macroporous structure. Figure 1a is a high-magnification transmission electron microscope image of the catalyst. It can be seen from the figure that the catalyst exhibits a two-dimensional loose porous structure containing mesopores and even micropores. These pore sizes provide good sites for subsequent catalytic reactions. The built-in picture in Figure 1b is the selected electron diffraction pattern of the area in Figure 1b. The annular halo-like structure indicates the amorphous uncertainty characteristics of the material. This feature facilitates electron transfer in persulfate activation. This characterization conclusion is consistent with the scanning electron microscopy image. In Figure 1, c, d, e, and g reflect the element distribution of the catalyst, which only contains carbon and oxygen elements and is evenly distributed. The elemental spectrum in Figure 1h further supports this conclusion. These characterizations indicate that the catalyst contains only carbon and oxygen elements, with oxygen used to modify the carbon substrate.

Inspired by the above characterization, Figure 2a is the X-ray diffraction pattern of O/C-8, which reflects that the catalyst only contains the (002) face and the (100) face, indicating uncertainty and graphite-like structure respectively. This is consistent with the above-mentioned high-magnification transmission spectrum characterization conclusion in Figure 1b. Figures 2b and 2c analyze the chemical composition of carbon and oxygen contained in the catalyst. In the C1s spectrum of Figure 2b, carbon-carbon double bonds and carbon-carbon single bonds can be seen. This structure is the main feature of graphitization. It also contains certain carbon-oxygen bonds and even trace amounts of nitrogen bonds. The carbon-oxygen bond mainly comes from the precursor ethylenediaminetetraacetic acid, while the trace nitrogen element mainly comes from the precursor dicyandiamide. The main function of ethylenediaminetetraacetic acid here is to provide an oxygen source for providing oxygen-containing functional groups on the carbon substrate. A small amount of the precursor dicyandiamide is mainly used as an activator. The volatilization during the pyrolysis process promotes the catalyst to form a loose and porous structure to facilitate the adhesion of the reactants. In the O1s spectrum in Figure 2b, it is clearly seen that oxygen contains carbon-oxygen double bonds (C=O) and carbon-oxygen single bonds (C-O), which well verifies the analysis of the chemical composition of carbon. This result illustrates the modification of oxygen on the carbon substrate, mainly forming the carbon-oxygen double bond (C=O, carbonyl) that has been widely reported to have an activated persulfate effect.

Figure 3a is the time distribution diagram of the removal of 2,4-dichlorophenol by common oxidants prepared by O/C-8 activation. It can be seen from this result that O/C-8 has the worst activation performance for H ₂ O ₂ and can hardly degrade organic matter. The performance of activated sodium periodate (PI) is second. Activated persulfates (including permonosulfate PMS and peroxydisulfate PDS) have the best performance and can degrade organic matter within 5 minutes. The differential reactivity produced by the activation of these oxidants by O/C-8 is related to the bond energy of the oxidants. As shown in Figure 3b. Considering the price and reaction performance of the oxidant, PDS is selected as the model oxidant in the present invention.

Based on the experimental results in Figure 3, Figure 4b selects O/C-8 activated PDS to degrade common but difficult-to-degrade organic compounds in different environmental waters, including phenol, sulfamethoxazole, 2,4-dichlorophenol, and bisphenol. A and tetracycline. It can be seen from the results that these organic pollutants are degraded to varying degrees. Among them, the degradation of 2,4-dichlorophenol, bisphenol A and tetracycline is the fastest, while the degradation of phenol and sulfamethoxazole is relatively slow. slow. This result shows that the active species in the O/C-8 activated PDS system have the characteristics of selective degradation of pollutants, rather than non-selective strong oxidative attack degradation. This characteristic gives the catalyst proposed in the present invention the potential to effectively deal with the treatment of actual water bodies. Because the actual water composition is complex, active species with selective degradation capabilities can meet this challenge.

Similarly, the above O/C-8 activated PDS system was used to treat 2,4-dichlorophenol organic pollutants in soil. The results are shown in Figure 4b. In the soil containing only 2,4-dichlorophenol, the concentration of 2,4-dichlorophenol did not attenuate. This implies that the soil ecosystem cannot spontaneously transform and migrate 2,4-dichlorophenol within the following time (360 min). Adding a certain amount of oxidant PDS also failed to reduce the concentration of 2,4-dichlorophenol. This implies that the complex soil environment does not have the ability to activate PDS to remove 2,4-dichlorophenol. However, when O/C-8 and PDS were present in the soil at the same time, the organic pollutant 2,4-dichlorophenol was significantly degraded, and the concentration dropped to almost zero within 360 minutes. This result strongly illustrates that the O/C-8 activated PDS system in the present invention can not only efficiently degrade organic matter in water, but also effectively remove organic matter in soil. In addition, Figure 5 shows the removal of total organic carbon from the degradation of 2,4-dichlorophenol in the above two systems. The experimental results reflect that the degradation of organic matter is a gradual mineralization process.

Figure 6 is a high-magnification X-ray photoelectron spectrum of oxygen in the O/C-T catalyst prepared at different temperatures in Example 2. The characterization results show that as the pyrolysis temperature increases, the oxygen content basically does not change. However, the carbonyl content gradually increased, from 12.76% in O/C-6.5 to 58.48% in O/C-9. Figure 6e further summarizes the carbonyl content in the O/C-T series catalysts. This set of experimental results proves the method proposed in the present invention to control the carbonyl content on the O/C-T surface. As mentioned above, the carbonyl group on the catalyst surface can serve as a catalytic site for activated PDS.

The results of the O/CT series catalyst activation of PDS for the degradation of furfuryl alcohol organic matter in Figure 7 confirm the above conclusion, that is, the carbonyl group can act as a catalytic site for activated PDS. Figure 7a shows that PDS activated by O/CT series catalysts can effectively degrade furfuryl alcohol. And as the pyrolysis temperature increases, the concentration of active species released by O/CT activated PDS increases, and the rate of degradation of furfuryl alcohol accelerates. Figure 7b uses the first-order reaction kinetic constant (k value, min ^-1 ) to describe the reaction speed. In the system of O/CT activated PDS, as the temperature increases, the k for the degradation of furfuryl alcohol increases. As shown in Figure 7c, the catalyst surface carbonyl content and their corresponding k values for activated PDS to degrade furfuryl alcohol showed a good exponential fitting relationship, with a confidence interval R ² =0.94. In order to further consolidate this conclusion, we performed a linear fitting of the pair function of k value and carbonyl content, as shown in Figure 7d, R ² =0.94. This experimental result strongly demonstrates that the carbonyl group on the catalyst surface acts as a site for activated PDS. This is the significance of regulating the carbonyl content.

Example 2

① Use the O/C-8 catalyst prepared in Example 1 as a template, add 100 mg O/C-8 to 100 mL glutaraldehyde solution (containing 50% volume water), and stir for 5 hours at room temperature using a magnetic stirrer. and 15 hours.

②After the above reaction is completed, use a filter membrane (0.2 μm) to perform solid-liquid separation in a suction filtration device to separate the O/C-8 catalyst and glutaraldehyde solution.

③ Wash the O/C-8 catalyst after the above treatment 3 to 5 times with ethanol and deionized water, dry it in a 60°C oven for 12 hours, and take it out for later use.

The catalyst obtained after stirring for 5 hours was named O/C-8 (moderate), where "moderate" means that the content of carbonyl groups is moderate. The catalyst obtained after stirring for 15 hours was named O/C-8 (too much), where "too much" means that the content of carbonyl groups is too much.

Example 3

① Using the O/C-8 catalyst prepared in Example 1 as a template, add 40 mg O/C-8 to 30 mL of 115 nM dansyl hydrazide solution, and add 1 mL of 0.1 M HCl solution to it. Stir for 30 hours at room temperature and protected from light.

②After the above reaction is completed, solid-liquid separation is performed using a filter membrane (0.2 μm) in the suction filtration device to separate the O/C-8 catalyst and the solution.

③ Wash the O/C-8 catalyst after the above treatment 3 to 5 times with ethanol and deionized water, dry it in a 60°C oven for 12 hours, and take it out for later use.

The obtained catalyst was named O/C-8 (too little), where "too little" means that the content of carbonyl groups is too little.

In addition to controlling the content of carbonyl groups on the surface of the catalyst by changing the temperature in Example 1, the present invention uses the method of glutaraldehyde modification in Example 2 to increase the content of carbonyl groups on the surface of the catalyst, and uses dansyl hydrazide modification in Example 3. The method reduces the carbonyl group content on the catalyst surface. As shown in Figure 8, the O/C-8 (excessive) and O/CT (moderate) obtained in Example 3 showed excessive and moderate carbonyl content respectively; while the O/C obtained in Example 4 -8 (too little) shows too little carbonyl content in the chemical analysis of oxygen. Figure 8i quantitatively summarizes the carbonyl content on O/C-8 (too little), O/C-8, O/C-8 (moderate) and O/C-8 (too much) catalysts. In order to further consolidate this conclusion, the inventor used Fourier transform infrared spectroscopy (as shown in Figure 9) to characterize the vibrations of the aforementioned four catalyst functional groups. The results show that carbonyl vibrations with wave numbers between 1600 and 1500 cm ^-1 are sequentially enhanced on O/C-8 (too little), O/C-8, (moderate) and O/C-8 (too much) catalysts. Other functional groups, such as C=C and CH, did not change significantly. The experimental results prove that there are differences in the methods of controlling carbonyl groups on the catalyst surface in Examples 2, 3 and 1: the former is surface modification, and the main framework of the catalyst, such as the specific surface area, is basically unchanged; the latter is temperature pyrolysis are different, resulting in different carbonyl content, this process may also lead to differences in the degree of graphitization and specific surface area of the catalyst. In actual applications, you can choose as needed.

Finally, Figure 10a uses electron paramagnetic resonance spectroscopy to characterize the results of PDS activated by O/C-8 (too little), O/C-8, O/C-8 (moderate), and O/C-8 (too much). the concentration of the active substance. Using 2,2,6,6-tetramethylpiperidone as the spin trapping reagent to capture the active species produced in the above four systems, the intensity is the highest in the O/C-8 (moderate) activated PDS system, while O/C-8 (too little) activates the PDS system with the smallest intensity. This implies that when the carbonyl concentration is appropriate, the concentration of active species produced by activated PDS is the strongest. As shown in Figure 10b, the above four systems were used to degrade furfuryl alcohol, and similar rules were obtained. That is, the O/C-8 (moderate) activated PDS system has the fastest degradation performance in removing furfuryl alcohol, while the O/C-8 (too little) system shows a rather slow degradation performance of furfuryl alcohol. Similarly, the above four systems showed similar rules for the degradation of 2,4-dichlorophenol, that is, the concentration of carbonyl groups was appropriate, and the performance of PDS activation and degradation of 2,4-dichlorophenol was the best.

Claims (9)

1. An oxygen modified carbon catalyst is characterized by being prepared by the following steps:

step 1, carrying out surface oxidation on ketjen black by adopting a nitric acid solution;

and 2, dispersing oxidized ketjen black in deionized water, sequentially adding ethylenediamine tetraacetic acid and dicyandiamide, uniformly mixing, drying the mixture, grinding, and performing pyrolysis under an inert gas atmosphere to obtain the oxygen modified carbon catalyst.

2. The oxygen-modified carbon catalyst of claim 1, wherein 80ml of 6m nitric acid solution is added per 200mg of ketjen black in step 1.

3. The oxygen-modified carbon catalyst according to claim 1, wherein the surface oxidation conditions in step 1 are 50 to 100 ^o C. And 6-24 hours.

4. The oxygen-modified carbon catalyst of claim 1, wherein in step 2, every 30mg of oxidized ketjen black is dispersed in 3mL of deionized water, followed by the sequential addition of 2.05g of ethylenediamine tetraacetic acid and 8g of dicyandiamide.

5. The oxygen-modified carbon catalyst of claim 1, wherein the pyrolysis conditions in step 2 are 650 to 900 ℃ for 1 to 3 hours.

6. The oxygen-modified carbon catalyst of claim 1, wherein glutaraldehyde or dansyl hydrazide is used to modify the oxygen-modified carbon catalyst to regulate the number of carboxyl groups distributed on the surface of the catalyst.

7. Use of the oxygen-modified carbon catalyst of any one of claims 1 to 6 for activating persulfates.

8. Use of the oxygen-modified carbon catalyst of any one of claims 1 to 6 for the catalytic degradation of organic pollutants in water and/or soil.

9. The use according to claim 8, characterized in that: the oxygen-modified carbon catalyst is used for catalyzing persulfate to degrade organic pollutants in water and/or soil.