Composite derived carbon catalyst, its preparation method and application

Abstract

This invention provides a composite derived carbon catalyst, its preparation method, and its application, belonging to the field of wastewater degradation technology. The preparation method includes the following steps: immersing denim single-thread fibers in a sodium hydroxide solution for ultrasonic treatment, followed by sequential drying and crushing; immersing fibrous denim in an iron salt aqueous solution, adding sodium hydroxide solution dropwise, and then sequentially allowing it to stand and dry; subjecting the dried product to pyrolysis under a nitrogen atmosphere, and post-treating the carbonized product to obtain the composite derived carbon catalyst. In this invention, iron clusters are uniformly distributed on the surface of the denim fiber-derived carbon, fully exposing active sites and thus providing higher catalytic activity and better degradation effect. This catalyst efficiently degrades various pollutants such as dyes, antibiotics, and phenols in wastewater within a wide pH range of 3-9, exhibiting the advantage of wide applicability.

Description

Technical Field

[0001] This invention relates to the field of wastewater degradation technology, and in particular to a composite derived carbon catalyst, its preparation method, and its application. Background Technology

[0002] With the increasingly active textile consumer market, the output of waste textiles is gradually increasing, especially waste denim. Denim is widely favored for its comfort and versatility, and its market demand continues to rise, leading to a surge in the generation of waste denim. In the resource utilization of waste denim, landfill disposal is prone to bacterial growth, and the recycling of lignin and short fibers is costly. Pyrolysis technology, however, not only effectively kills pathogens but also preserves carbon to the maximum extent, which helps reduce greenhouse gas emissions. Waste denim is mainly composed of pure cotton or cotton blends, with a single material and high fiber strength, making recycling relatively simple and the easiest type of textile to achieve large-scale, high-value recycling. Carbonized waste denim retains its porous structure and rich functional groups, and possesses a certain degree of mechanical strength. The application of carbon-based denim materials in water treatment has become a focus of attention in recent years.

[0003] Sulfonamide antibiotics, with sulfamethoxazole (SMX) as a typical example, are environmentally persistent, and their metabolic intermediates are frequently reduced to their parent structure through the metabolism of microorganisms and plants. SMX and its metabolic intermediates are toxic, not only disrupting the normal metabolic activities of functional microorganisms in wastewater treatment systems and reducing microbial community stability, but also promoting the accumulation of resistance genes (ARGs) in sludge, posing a potential risk to sludge disposal. Sulfamethoxazole exceeding environmental capacity poses a long-term threat to the ecological environment, making its efficient degradation an urgent priority. However, traditional coagulation and filtration methods are ineffective in capturing and removing low concentrations of sulfamethoxazole, while advanced oxidation technologies can address this challenge.

[0004] Currently, most patents on metal-carbon composite catalysts for activating peracetic acid use conventional biomass as the carbon source, with very few targeting carbon derived from waste denim. Therefore, this paper proposes a method that uses waste denim as a carbon source and constructs a carbon-based catalyst through metal doping to efficiently activate peracetic acid to degrade antibiotic wastewater. This approach combines the advantages of high-value utilization of waste denim resources with the development of low-cost antibiotic treatment technologies, and is of great significance for advancing environmental governance methods that treat waste with waste. Summary of the Invention

[0005] The purpose of this invention is to provide a composite derived carbon catalyst, its preparation method, and its application. The metal is uniformly doped onto waste denim by an impregnation method, and then the metal particles are grown in situ on carbon nanofibers in a high-temperature pyrolysis process. The composite carbon nanocatalyst prepared by this invention has the characteristics of controllable structure and uniform metal particle loading, and aims to solve the problems of difficulty in high-value utilization of waste textiles and insufficient exposure sites of metal particles.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a composite derived carbon catalyst, comprising the following steps: 1) Soak the denim fabric in a sodium hydroxide solution and sonicate it, then dry and crush it in sequence to obtain wavy denim fabric; 2) The wavy denim fabric was soaked in an iron salt solution, and sodium hydroxide solution was added dropwise. The mixture was then allowed to stand and dried sequentially to obtain the dried product. 3) The dried product is pyrolyzed under a nitrogen atmosphere to obtain a composite derived carbon catalyst.

[0007] Preferably, in step 1), the length of the denim single thread is 1.2~1.7cm, the mass-to-volume ratio of the denim single thread to the sodium hydroxide solution is 8~12g:170~230mL, the concentration of the sodium hydroxide solution is 0.7~1.3mol / L, the ultrasonic treatment time is 0.5~1.5h, the drying temperature is 75~85℃, and the drying time is 10~14h.

[0008] Preferably, the ferrous salt aqueous solution in step 2) is composed of ferrous salt, ferric salt, polyethylene glycol and water. The total molar amount of ferrous salt and ferric salt to the volume of polyethylene glycol is 10~20 mmol: 1.3~1.7 mL, the molar ratio of ferrous salt to ferric salt is 1:1.5~2.5, the volume ratio of polyethylene glycol, water and sodium hydroxide solution is 1.3~1.7:52~62:15~25, and the concentration of sodium hydroxide solution is 1~2 mol / L.

[0009] Preferably, in step 2), the mass-to-volume ratio of the wavy denim fabric and the iron salt aqueous solution is 1.5~2.5g:55~65mL; ​​the soaking time is 45~52h; the standing time is 2~4h; the drying temperature is 75~85℃; and the drying time is 10~14h.

[0010] Preferably, the pyrolysis treatment in step 3) is performed at a temperature of 750~850℃, for a time of 100~140min, at a rate of 3~7℃ / min, and at a flow rate of 180~220mL / min.

[0011] Preferably, the carbonized product obtained by the pyrolysis treatment in step 3) is subjected to post-treatment, which includes washing, drying and sieving in sequence. The washing reagent is water, the drying temperature is 75~85℃, and the drying time is 0.5~1.5h.

[0012] The present invention also provides a composite derived carbon catalyst prepared by the aforementioned preparation method.

[0013] The present invention also provides the application of the composite derived carbon catalyst in wastewater treatment, wherein the composite derived carbon catalyst, oxidant and wastewater containing pollutants are mixed, and the mixture is reacted to obtain treated wastewater.

[0014] Preferably, in the mixture, the concentration of the composite derived carbon catalyst is 50-300 mg / L, the concentration of the oxidant is 0.1-0.4 mmol / L, and the oxidant includes persulfate and / or peracetic acid; the reaction temperature is 15-30°C, the reaction time is 0.5-1 h; the reaction is stirred at a rate of 400-600 r / min; and the contaminant includes sulfamethoxazole.

[0015] The beneficial effects of this invention are: 1) This invention uses denim fabric as a carrier to load iron to prepare denim composite-derived carbon catalyst. The pyrolysis treatment gives the catalyst surface a large specific surface area and abundant functional groups, which can effectively disperse metal particles and reduce metal ion leaching. It can also efficiently activate a variety of oxidants for the degradation of sulfamethoxazole.

[0016] 2) Iron clusters are uniformly distributed on the surface of denim fiber-derived carbon, fully exposing active sites and thus providing higher catalytic activity and achieving better degradation results. The iron-loaded denim composite-derived carbon catalyst of this invention has advantages such as low raw material cost and high economic benefits, providing a new approach for the treatment of pollutant wastewater and the recycling of waste denim.

[0017] 3) The iron-loaded denim composite-derived carbon catalyst of the present invention exhibits high catalytic activity when degrading pollutants in the presence of multiple anions; and the catalyst can efficiently degrade various pollutants such as dyes, antibiotics, and phenols in wastewater within a wide pH range of 3 to 9, and has the advantage of wide applicability. Attached Figure Description

[0018] Figure 1 X-ray diffraction patterns of the Fe@WDCF catalysts prepared in Examples 1-3, Comparative Example 1, and Comparative Example 2; Figure 2 The particle size distribution diagram of the Fe4@WDCF catalyst surface nanoparticles prepared in Example 1 is shown. Figure 3 Scanning electron microscope (SEM) images of the Fe4@WDCF catalyst prepared in Example 1 and the WDCF catalyst prepared in Comparative Example 2; Figure 4 Electrochemical impedance spectroscopy (EIC) diagrams of the Fe4@WDCF catalyst prepared in Example 1 and the WDCF catalyst prepared in Comparative Example 2; Figure 5 The graphs show the effect of application example 1 and comparative application examples 1-5 on the degradation of sulfamethoxazole; Figure 6 The graphs show the effects of application examples 1-2 and comparative application example 4 on the degradation of sulfamethoxazole; Figure 7 The graphs show the effects of application example 1, application example 3, and comparative application example 3 on the degradation of sulfamethoxazole. Figure 8 The graphs show the effects of activated peracetic acid on the degradation of different pollutants in Application Examples 1 and 4. Detailed Implementation

[0019] This invention provides a method for preparing a composite derived carbon catalyst, comprising the following steps: 1) Soak the denim fabric in a sodium hydroxide solution and sonicate it, then dry and crush it in sequence to obtain wavy denim fabric; 2) The wavy denim fabric was soaked in an iron salt solution, and sodium hydroxide solution was added dropwise. The mixture was then allowed to stand and dried sequentially to obtain the dried product. 3) The dried product is pyrolyzed under a nitrogen atmosphere to obtain a composite derived carbon catalyst.

[0020] In this invention, the length of the denim single thread in step 1) is preferably 1.2~1.7cm, more preferably 1.3~1.6cm, and even more preferably 1.4~1.5cm; the mass-to-volume ratio of the denim single thread to the sodium hydroxide solution is preferably 8~12g:170~230mL, more preferably 9~11g:180~220mL, and even more preferably 10g:190~200mL; the concentration of the sodium hydroxide solution is preferably 0.7~1.3mol / L, more preferably 0.8~1.2mol / L, and even more preferably 0.9~1mol / L; the ultrasonic treatment time is preferably 0.5~1.5h, more preferably 0.7~1.2h, and even more preferably 1h; the drying temperature is preferably 75~85℃, more preferably 78~82℃, and even more preferably 80℃; and the drying time is preferably 10~14h, more preferably 11~13h, and even more preferably 12h.

[0021] In this invention, the denim single thread is obtained by splitting denim fabric, which includes waste denim fabric; the product of ultrasonic treatment is washed with water until neutral before drying.

[0022] In this invention, the ferrous salt aqueous solution in step 2) is preferably composed of ferrous salt, ferric salt, polyethylene glycol, and water. The ratio of the total molar amount of ferrous salt and ferric salt to the volume of polyethylene glycol is preferably 10-20 mmol: 1.3-1.7 mL, more preferably 12-18 mmol: 1.4-1.6 mL, and even more preferably 14-16 mmol: 1.5 mL. The molar ratio of ferrous salt to ferric salt is preferably 1:1.5-2.5, more preferably 1:1.7-2.3, and even more preferably 1:2. The volume ratio of polyethylene glycol, water, and sodium hydroxide solution is preferably 1.3-1.7: 52-62: 15-25, more preferably 1.4-1.6: 55-60: 17-23, and even more preferably 1.5: 57-58: 20-22. The concentration of sodium hydroxide solution is preferably 1-2 mol / L, more preferably 1.2-1.8 mol / L, and even more preferably 1.5-1.6 mol / L.

[0023] In this invention, the iron salt aqueous solution of the flocculent denim is continuously stirred during the addition of sodium hydroxide solution until it turns completely black and is then left to stand.

[0024] In this invention, the preferred mass-to-volume ratio of the fibrous denim fabric and the iron salt aqueous solution in step 2) is 1.5~2.5g:55~65mL, more preferably 1.7~2.3g:57~63mL, and even more preferably 1.9~2g:60~62mL; the preferred soaking time is 45~52h, more preferably 48~50h; the preferred standing time is 2~4h, more preferably 2.5~3.5h, and even more preferably 3h; the preferred drying temperature is 75~85℃, more preferably 78~82℃, and even more preferably 80℃; and the preferred drying time is 10~14h, more preferably 11~13h, and even more preferably 12h.

[0025] In this invention, the pyrolysis temperature in step 3) is preferably 750~850℃, more preferably 770~830℃, and even more preferably 800℃; the pyrolysis time is preferably 100~140min, more preferably 110~130min, and even more preferably 120min; the rate of heating to the pyrolysis temperature is preferably 3~7℃ / min, more preferably 4~6℃ / min, and even more preferably 5℃ / min; and the nitrogen flow rate is preferably 180~220mL / min, more preferably 190~210mL / min, and even more preferably 200mL / min.

[0026] In this invention, the carbonized product obtained by the pyrolysis treatment in step 3) is subjected to post-treatment. The post-treatment preferably includes washing, drying and sieving in sequence. The washing reagent is preferably water. The water is used to wash several times to remove ash. The drying temperature is preferably 75~85℃, more preferably 77~83℃, and more preferably 80℃. The drying time is preferably 0.5~1.5h, more preferably 1h. The sieve mesh size is preferably 120~200 mesh.

[0027] The present invention also provides a composite derived carbon catalyst prepared by the aforementioned preparation method.

[0028] The present invention also provides the application of the composite derived carbon catalyst in wastewater treatment, wherein the composite derived carbon catalyst, oxidant and wastewater containing pollutants are mixed, and the mixture is reacted to obtain treated wastewater.

[0029] In the mixture of the present invention, the concentration of the composite derived carbon catalyst is preferably 50-300 mg / L, more preferably 100-250 mg / L, and even more preferably 150-200 mg / L; the concentration of the oxidant is preferably 0.1-0.4 mmol / L, more preferably 0.2-0.3 mmol / L, and even more preferably 0.25 mmol / L; the oxidant preferably includes persulfate and / or peracetic acid; the reaction temperature is preferably 15-30°C, more preferably 20-25°C; the reaction time is preferably 0.5-1 h; stirring is performed during the reaction, and the stirring rate is preferably 400-600 r / min, more preferably 500 r / min; the pollutant is preferably an antibiotic, and the antibiotic is preferably sulfamethoxazole.

[0030] The composite derived carbon catalyst of this invention is applied in the field of environmental catalysis, particularly in the field of heterogeneous advanced oxidation. This invention uses waste denim as a carrier to prepare the catalyst for wastewater treatment. The high-value and low-carbon transformation of waste denim is beneficial to promoting the circular economy and achieving "waste-to-waste treatment." A one-step carbonization technology is used to achieve in-situ and uniform loading of metals, fully exposing active sites, thereby efficiently activating the oxidant peracetic acid and achieving efficient degradation of low-concentration dye molecules, antibiotics, and phenolic pollutants in wastewater. The preparation method of this invention is simple, the raw materials are widely available, it has strong anti-interference ability, and it is not prone to causing secondary pollution.

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] Example 1

[0033] Waste denim fabric was split into denim threads with a length of 1.5cm. 10g of denim thread was soaked in 200mL of 1mol / L NaOH aqueous solution and ultrasonically treated (power 300W) for 1h. After washing with water until neutral, it was dried in an oven at 80℃ for 12h. Then it was broken into flocculent form to obtain flocculent denim fabric.

[0034] 1.112g FeSO4·7H2O and 2.16g FeCl3·6H2O were dissolved in 60mL of polyethylene glycol aqueous solution (the polyethylene glycol aqueous solution contained 1.5mL of polyethylene glycol 400) to obtain an iron salt aqueous solution; 2g of wavy denim was soaked in the iron salt aqueous solution for 48h, and then 20mL of 1.5mol / L NaOH aqueous solution was added dropwise to the denim iron salt aqueous solution. During this process, the solution was stirred continuously until the denim iron salt solution turned completely black and then stood for 3h. After that, it was placed in an oven at 80℃ and dried for 12h.

[0035] The dried material was transferred to an aluminum chloride boat and heated to 800°C at a rate of 5°C / min under a nitrogen atmosphere (nitrogen flow rate of 200 mL / min). The calcined product was then washed three times with deionized water, dried at 80°C for 1 hour, and then ground into powder and passed through a 200-mesh sieve to obtain the composite derived carbon catalyst (Fe4@WDCF catalyst).

[0036] Example 2

[0037] The 1.112g FeSO4·7H2O and 2.16g FeCl3·6H2O in Example 1 were replaced with 1.39g FeSO4·7H2O and 2.70g FeCl3·6H2O, and the other process conditions were the same as in Example 1, to obtain the Fe5@WDCF catalyst.

[0038] Example 3

[0039] The Fe6@WDCF catalyst was obtained by replacing 1.112g FeSO4·7H2O and 2.16g FeCl3·6H2O in Example 1 with 1.67g FeSO4·7H2O and 3.24g FeCl3·6H2O, while keeping other process conditions the same as in Example 1.

[0040] Comparative Example 1

[0041] The Fe3@WDCF catalyst was obtained by replacing 1.112g FeSO4·7H2O and 2.16g FeCl3·6H2O in Example 1 with 0.834g FeSO4·7H2O and 1.62g FeCl3·6H2O, while keeping other process conditions the same as in Example 1.

[0042] Comparative Example 2

[0043] The 1.112g FeSO4·7H2O and 2.16g FeCl3·6H2O in Example 1 were omitted, and the iron salt aqueous solution was replaced with a polyethylene glycol aqueous solution. Other process conditions were the same as in Example 1, and the WDCF catalyst was obtained.

[0044] The X-ray diffraction patterns of the Fe@WDCF catalyst prepared in Examples 1-3, Comparative Example 1, and Comparative Example 2 are shown below. Figure 1 As shown, by Figure 1 It can be seen that the Fe4@WDCF catalyst retains the fibrous structure, and the iron clusters are evenly distributed on the surface of the denim fibers.

[0045] The particle size distribution of the Fe4@WDCF catalyst surface nanoparticles prepared in Example 1 is shown in the figure below. Figure 2 As shown, high-resolution transmission electron microscopy (EDS) imaging further confirms the uniform distribution of carbon, oxygen, iron, and sulfur on the surface of the nanofibers.

[0046] Scanning electron microscope (SEM) images of the Fe4@WDCF catalyst prepared in Example 1 and the WDCF catalyst prepared in Comparative Example 2 are shown below. Figure 3 As shown.

[0047] Example 4

[0048] Waste denim fabric was split into denim threads with a length of 1.3cm. 9g of denim thread was soaked in 180mL of 0.8mol / L NaOH aqueous solution and ultrasonically treated for 0.7h. After washing with water until neutral, it was dried in an oven at 78℃ for 13h. Then it was broken into flocculent form to obtain flocculent denim fabric.

[0049] 1.668g of FeSO4·7H2O and 3.24g of FeCl3·6H2O were dissolved in 62mL of polyethylene glycol aqueous solution (the polyethylene glycol aqueous solution contained 1.3mL of polyethylene glycol 400) to obtain an iron salt aqueous solution; 2g of wavy denim was soaked in the iron salt aqueous solution for 45h, and then 22mL of 1.2mol / L NaOH aqueous solution was added dropwise to the denim iron salt aqueous solution. During this process, the solution was stirred continuously until the denim iron salt solution turned completely black, and then left to stand for 2.5h. After that, it was placed in an oven at 78℃ and dried for 13h.

[0050] The dried material was transferred to an aluminum chloride boat and heated to 770°C at a rate of 4°C / min under a nitrogen atmosphere (nitrogen flow rate of 190 mL / min). The calcined product was then washed three times with deionized water, dried at 77°C for 1.5 h, ground into powder, and passed through a 120-mesh sieve to obtain the composite derived carbon catalyst.

[0051] Example 5

[0052] Waste denim fabric was split into denim threads with a length of 1.7cm. 11g of denim thread was soaked in 220mL of 1.2mol / L NaOH aqueous solution and ultrasonically treated for 1.2h. After washing with water until neutral, it was dried in an oven at 82℃ for 11h. Then it was broken into flocculent form to obtain flocculent denim fabric.

[0053] 1.39 g of FeSO4·7H2O and 2.7 g of FeCl3·6H2O were dissolved in 58 mL of polyethylene glycol aqueous solution (the polyethylene glycol aqueous solution contained 1.7 mL of polyethylene glycol 400) to obtain an iron salt aqueous solution; 2 g of wavy denim was soaked in the iron salt aqueous solution for 50 h, and then 17 mL of 1.8 mol / L NaOH aqueous solution was added dropwise to the denim iron salt aqueous solution. During this process, the solution was stirred continuously until the denim iron salt solution turned completely black and then stood for 3.5 h. After that, it was placed in an oven at 82 °C and dried for 11 h.

[0054] The dried material was transferred to an aluminum chloride boat and heated to 830°C at a rate of 6°C / min under a nitrogen atmosphere (nitrogen flow rate of 210 mL / min). The calcined product was then washed three times with deionized water, dried at 83°C for 1 hour, and then ground into powder and passed through a 200-mesh sieve to obtain the composite derived carbon catalyst.

[0055] The composite derived carbon catalyst prepared in Example 1 was loaded onto an ITO electrode for electrocatalytic performance testing. The specific process was as follows: First, 10 mg of the composite derived carbon catalyst from Example 1 was added to ethanol (950 mL / min). L water and 950 (a mixture of L anhydrous ethanol), then add 50 L Nafion solution, sonicated for 15 min. Take 100 The sample after sonication was dropped onto a clean ITO electrode (1 cm). The catalyst was dried at room temperature on a 2.5 cm plate for testing. An ITO electrode supported on the catalyst was used as the working electrode, a platinum electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was a 0.5 mol / L potassium ferricyanide aqueous solution. EIS tests were performed on WDCF and Fe4@WDCF at open-circuit potential, with a test frequency range of 100 kHz to 0.1 Hz and an AC amplitude of 10 mV.

[0056] The electrochemical impedance spectroscopy (EIC) diagrams of the Fe4@WDCF catalyst prepared in Example 1 and the WDCF catalyst prepared in Comparative Example 2 are shown below. Figure 4 As shown, by Figure 4It can be seen that the slope of Fe4@WDCF in the low-frequency region is greater than that of WDCF, indicating that it has the lowest charge transfer impedance. The electron transport rate of Fe4@WDCF is faster than that of WDCF, and Fe4@WDCF has a higher specific capacitance and greater catalytic potential than WDCF.

[0057] Application Example 1

[0058] 10 mg of the Fe4@WDCF catalyst from Example 1 was added to 100 mL of simulated sulfamethoxazole (SMX) wastewater at a concentration of 10 mg / L. After uniform dispersion, peracetic acid (PAA) was added to initiate the reaction. The initial concentration of PAA in the system was 0.2 mmol / L. The concentration change of SMX was monitored over a certain period of time.

[0059] Comparative Application Example 1

[0060] 10 mg of WDCF catalyst from Comparative Example 2 was added to 100 mL of simulated wastewater containing sulfamethoxazole (SMX) at a concentration of 10 mg / L, and the concentration change of SMX was detected over a certain period of time.

[0061] Comparative Application Example 2

[0062] Peracetic acid (PAA) was added to 100 mL of simulated wastewater containing sulfamethoxazole (SMX) at a concentration of 10 mg / L. The initial PAA concentration in the system was 0.2 mmol / L. The concentration change of SMX was monitored over a certain period of time.

[0063] Comparative Application Example 3

[0064] 10 mg of WDCF catalyst (Comparative Example 2) was added to 100 mL of simulated sulfamethoxazole (SMX) wastewater at a concentration of 10 mg / L. After uniform dispersion, peracetic acid (PAA) was added to initiate the reaction. The initial PAA concentration in the system was 0.2 mmol / L. The concentration change of SMX was monitored over a certain period of time.

[0065] Comparative Application Example 4

[0066] 10 mg of the Fe4@WDCF catalyst from Example 1 was added to 100 mL of simulated sulfamethoxazole (SMX) wastewater with a concentration of 10 mg / L, and the concentration change of SMX was detected over a certain period of time.

[0067] Comparative Application Example 5

[0068] 10 mg of the Fe4@WDCF catalyst from Example 1 was added to 100 mL of simulated sulfamethoxazole (SMX) wastewater with a concentration of 10 mg / L. After uniform dispersion, hydrogen peroxide aqueous solution (H2O2) was added to initiate the reaction. The initial concentration of H2O2 in the system was 0.2 mmol / L. The concentration change of SMX was monitored over a certain period of time.

[0069] Application Example 2

[0070] Replace peracetic acid (PAA) in Application Example 1 with permonosulfate (PMS), and keep other process conditions the same as in Application Example 1.

[0071] Application Example 3

[0072] The Fe4@WDCF catalyst in Example 1 of Application Example 1 was replaced with the Fe5@WDCF catalyst of Example 2, the Fe6@WDCF catalyst of Example 3, and the Fe3@WDCF catalyst of Comparative Example 1, respectively, while other process conditions were the same as in Application Example 1.

[0073] Application Example 4

[0074] In Application Example 1, sulfamethoxazole (SMX) was replaced with methylene blue (MB) (25 mg / L), methyl orange (MO) (25 mg / L), tetracycline hydrochloride (TCH) (10 mg / L), bisphenol A (BPA) (10 mg / L), and p-nitrophenol (p-NP) (10 mg / L), respectively, while other process conditions remained the same as in Application Example 1.

[0075] The effect graphs of the degradation of sulfamethoxazole in Application Example 1 and Comparative Application Examples 1-5 are shown below. Figure 5 As shown. By Figure 5 It can be seen that Fe4@WDCF significantly improves the performance of activating peracetic acid in degrading sulfamethoxazole compared to WDCF; and the efficiency of sulfamethoxazole degradation is consistent with the test results of EIS.

[0076] The effect graphs of the degradation of sulfamethoxazole in application examples 1-2 and comparative application example 4 are shown below. Figure 6 As shown. By Figure 6 It can be seen that Fe4@WDCF has a good activating effect on both peracetic acid and persulfate, and the degradation effect of Fe4@WDCF / PAA system and Fe4@WDCF / PMS system on sulfamethoxazole reaches more than 60%.

[0077] The effect graphs of the degradation of sulfamethoxazole in Application Example 1, Application Example 3, and Comparative Application Example 3 are shown in the figure. Figure 7 As shown. By Figure 7It can be seen that when there is no metal doping, pure carbon material WDCF will hardly activate PAA to degrade SMX; the removal rate of SMX by the Fe3@WDCF catalyst in Comparative Example 1 is only 50%; the removal rates of SMX by the Fe4@WDCF catalyst, Fe5@WDCF catalyst and Fe6@WDCF catalyst in Examples 1-3 are all higher than 90%.

[0078] The comparison diagram of the effects of activated peracetic acid on the degradation of different pollutants in Application Examples 1 and 4 is shown in the figure below. Figure 8 As shown. By Figure 8 It can be seen that the Fe4@WDCF / PAA system has wide applicability and achieves a degradation effect of over 70% on a variety of pollutants.

[0079] The method of this invention is simple and easy to implement, and innovatively proposes a one-step strategy for the resource utilization of waste denim and the synthesis of metal-derived carbon from waste denim. The metal-carbon based catalyst prepared by this invention achieves uniform loading of metal nanoparticles, improving the catalyst's activity and stability. This invention provides a new resource utilization strategy for waste denim and offers insights into its application in advanced oxidation water treatment.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a composite derived carbon catalyst, characterized in that, It includes the following steps: 1) Soak the denim fabric in sodium hydroxide solution and sonicate it, then dry and crush it in sequence to obtain wavy denim fabric; 2) The wavy denim fabric was soaked in an iron salt solution, and sodium hydroxide solution was added dropwise. The mixture was then allowed to stand and dried sequentially to obtain the dried product. 3) The dried product is pyrolyzed under a nitrogen atmosphere to obtain a composite derived carbon catalyst.

2. The preparation method according to claim 1, characterized in that, Step 1) The length of the denim single thread is 1.2~1.7cm, the mass-to-volume ratio of the denim single thread to the sodium hydroxide solution is 8~12g:170~230mL, the concentration of the sodium hydroxide solution is 0.7~1.3mol / L, the ultrasonic treatment time is 0.5~1.5h, the drying temperature is 75~85℃, and the drying time is 10~14h.

3. The preparation method according to claim 1 or 2, characterized in that, Step 2) The ferrous salt aqueous solution is composed of ferrous salt, ferric salt, polyethylene glycol and water. The total molar amount of ferrous salt and ferric salt to the volume of polyethylene glycol is 10~20 mmol: 1.3~1.7 mL, the molar ratio of ferrous salt to ferric salt is 1:1.5~2.5, the volume ratio of polyethylene glycol, water and sodium hydroxide solution is 1.3~1.7:52~62:15~25, and the concentration of sodium hydroxide solution is 1~2 mol / L.

4. The preparation method according to claim 3, characterized in that, Step 2) The mass-to-volume ratio of the wavy denim fabric and the iron salt aqueous solution is 1.5~2.5g:55~65mL; ​​the soaking time is 45~52h; the standing time is 2~4h; the drying temperature is 75~85℃; and the drying time is 10~14h.

5. The preparation method according to claim 4, characterized in that, Step 3) The pyrolysis treatment temperature is 750~850℃, the pyrolysis treatment time is 100~140min, the rate of heating to the pyrolysis treatment temperature is 3~7℃ / min, and the flow rate of nitrogen gas is 180~220mL / min.

6. The preparation method according to claim 5, characterized in that, Step 3) The carbonized product obtained by the pyrolysis treatment is subjected to post-treatment, which includes washing, drying and sieving in sequence. The washing reagent is water, the drying temperature is 75~85℃ and the drying time is 0.5~1.5h.

7. The composite derived carbon catalyst prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the composite derived carbon catalyst according to claim 7 in wastewater treatment, characterized in that, The composite derived carbon catalyst, oxidant, and wastewater containing pollutants are mixed and reacted to obtain treated wastewater.

9. The application according to claim 8, characterized in that, In the mixture, the concentration of the composite derived carbon catalyst is 50-300 mg / L, the concentration of the oxidant is 0.1-0.4 mmol / L, and the oxidant includes persulfate and / or peracetic acid; the reaction temperature is 15-30℃, the reaction time is 0.5-1 h; the reaction is stirred at a rate of 400-600 r / min; the contaminant includes sulfamethoxazole.

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