Preparation method, product and application of Co / CN coated SiO2 composite material

Abstract

The invention discloses a preparation method, a product and application of a Co / CN coated SiO2 composite material, and belongs to the technical field of wastewater treatment. The Co / CN coated SiO2 composite material comprises a silicon dioxide carrier, cobalt nanoparticles loaded on the carrier and a carbon nitrogen layer coated on the surfaces of the cobalt nanoparticles. The preparation method comprises the following steps: firstly, preparing the silicon dioxide carrier; and mixing cobalt nitrate hexahydrate, the silicon dioxide carrier and a buffer solution, stirring, adding dopamine, reacting at room temperature to obtain a black brown product, washing, and calcining in an inert atmosphere to obtain the Co / CN coated SiO2 composite material. The material can efficiently catalyze and degrade organic dyes such as bisphenol A, methyl orange and the like in the presence of peroxymonosulfonate, has the advantages of mild reaction conditions, high catalytic activity, good stability and the like, and is suitable for treating organic polluted wastewater.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a preparation method, product and application of a Co / CN@SiO2 composite material. BACKGROUND

[0002] In the process of rapid industrial production and social economic development, water pollution has become one of the major environmental challenges faced by mankind in the 21st century. The discharge of a large amount of industrial wastewater and domestic sewage not only destroys the ecological balance of natural water bodies, but also poses a serious threat to human health and sustainable development. Water pollution can be divided into biological pollution, physical pollution and chemical pollution according to the nature of the pollutants, among which chemical pollution is particularly difficult to control due to the complexity of the composition of the pollutants and the long-lasting harm. Organic dye pollutants, as a typical representative of chemical pollution, are widely derived from the textile, printing and dyeing, plastic and other industries, and common types include methyl orange, bisphenol A, rhodamine B, etc. Among these pollutants, bisphenol A has significant toxicity and potential carcinogenicity, and cannot be decomposed by natural biological degradation process. Once it enters the water environment, it will accumulate for a long time and be enriched through the food chain, causing irreversible damage to aquatic organisms, soil ecology and human health, and thus has become the focus of attention in the field of water pollution control.

[0003] For a long time, the treatment of organic dye wastewater mainly relies on physical treatment methods (such as adsorption, filtration), chemical treatment methods (such as oxidation-reduction, coagulation and sedimentation) and biological treatment methods (such as activated sludge, biofilm method). However, with the continuous strictness of global environmental standards and the continuous emergence of new types of refractory organic pollutants, the limitations of traditional treatment technologies are increasingly prominent: physical treatment methods only achieve the transfer of pollutants rather than complete degradation, and are prone to secondary pollution; chemical treatment methods often require a large amount of chemical agents, and have problems such as high operating cost and agent residue; biological treatment methods have poor tolerance to toxic pollutants, and have long processing period and low efficiency. These defects make it difficult for traditional methods to meet the current demand for efficient, environmentally friendly and low-cost water pollution control, and the development of new water treatment technologies has become an urgent task in the field of environmental engineering.

[0004] In recent years, catalytic degradation technology based on advanced oxidation processes (AOPs) has been able to generate strong oxidizing active species (such as hydroxyl radicals OH, sulfate radicals SO4 -·, etc.), which can quickly and completely mineralize organic pollutants, has shown broad application prospects in the field of organic dye wastewater treatment. Among them, cobalt-based catalysts have become one of the core materials in advanced oxidation processes due to their excellent catalytic activity and relatively low preparation cost. However, there are still obvious deficiencies in the practical application of pure cobalt-based catalysts: cobalt nanoparticles are prone to agglomeration, resulting in a decrease in specific surface area and insufficient exposure of active sites; at the same time, the stability of the catalyst in the reaction system is poor, and it is easy to dissolve out and cause secondary pollution, which seriously restricts its industrial application. Therefore, how to solve the agglomeration and stability problems of cobalt-based catalysts through structure design and carrier modification, and further improve its catalytic efficiency, has become a key research direction to promote the application of advanced oxidation technology. SUMMARY

[0005] In view of the above technical problems, the present application provides a preparation method, product and application of Co / CN@SiO2 composite material, and the catalytic degradation performance of the catalyst on bisphenol A is systematically studied. The structure and morphology are characterized by SEM, and the catalytic mechanism is discussed, which provides theoretical basis and practical guidance for developing efficient and stable organic dye degradation catalysts.

[0006] To achieve the above object, the present application provides the following technical scheme:

[0007] One of the objects of the present application is to provide a Co / CN@SiO2 composite material, comprising a silicon dioxide carrier, cobalt nanoparticles loaded on the carrier, and a carbon-nitrogen layer coated on the surface of the cobalt nanoparticles.

[0008] The second object of the present application is to provide a preparation method of Co / CN@SiO2 composite material, comprising the following steps:

[0009] Mix ethanol, ammonia water and distilled water, heat to 60℃, add tetraethyl orthosilicate for heating reaction, and after centrifugation, washing and drying, obtain a silicon dioxide carrier;

[0010] Mix cobalt nitrate hexahydrate, the silicon dioxide carrier and a buffer solution, stir, then add dopamine, react at room temperature to obtain a black-brown product, wash, and perform calcination treatment in an inert atmosphere to obtain the Co / CN@SiO2 composite material.

[0011] The present application utilizes persulfate to generate strong oxidizing free radicals, which can effectively decompose organic pollutants such as bisphenol A. This technology has the advantages of high efficiency, rapidity, wide applicability, etc., and has broad application prospects in the fields of water treatment, soil remediation, etc.

[0012] Further, the volume ratio of the ethanol, ammonia water and tetraethyl orthosilicate is 225:150:17.5.

[0013] Further, the heating reaction time is 120 minutes.

[0014] Further, the mass ratio of the cobalt nitrate hexahydrate, the silica carrier and the dopamine is (0.309-4.94):(0.125-2.0):0.0216, such as 0.309g, 0.618g, 1.235g, 2.47g or 4.94g of cobalt nitrate hexahydrate; 0.125g, 0.25g, 0.5g, 1.0g or 2.0g of the silica carrier; and 0.0216g of dopamine; preferably the mass ratio is 0.618:1.0:0.0216, and the mass ratio of the cobalt nitrate hexahydrate to the silica carrier is preferably 0.618:1.0.

[0015] Further, the reaction time at room temperature is 6-48 hours, such as 6 hours, 12 hours, 18 hours, 24 hours or 48 hours; preferably 18 hours.

[0016] Further, the calcination treatment is calcination at 400-800℃ for 2 hours, such as 400℃, 500℃, 600℃, 700℃ or 800℃, preferably 600℃.

[0017] The third object of the present application is to provide an application of the Co / CN@SiO2 composite material in catalytic degradation of organic dyes.

[0018] Further, the organic dyes include bisphenol A, rhodamine B, methyl orange or coomassie brilliant blue.

[0019] Further, the catalytic degradation is carried out in the presence of peroxymonosulfate (such as potassium peroxymonosulfate, PMS), and the concentration of the peroxymonosulfate is 14-18g / L, such as 14g / L, 15g / L, 16g / L, 17g / L or 18g / L, preferably 16g / L; and the pH value of the reaction system is 4.5-9.7, such as pH=4.50, pH=6.09, pH=7.97 or pH=9.68.

[0020] Compared with the prior art, the present application has the following advantages and technical effects:

[0021] This invention develops a novel, highly efficient, and stable catalyst by designing and optimizing the preparation process of porous Co / CN@SiO2 composite materials, providing effective technical support for the degradation of organic pollutants such as bisphenol A in water. Furthermore, this invention optimizes the reaction conditions of the porous Co / CN@SiO2 composite material to more comprehensively reveal the working principle of porous materials in catalytic reactions and lay a solid theoretical foundation for designing more efficient catalytic materials. Moreover, the application scope of the porous Co / CN@SiO2 composite material is not limited to the degradation of bisphenol A but can be extended to the treatment of various other organic pollutants, demonstrating broad application prospects. Therefore, the results of this invention are expected to provide new ideas and strategies for environmental pollution control and functional material development, possessing both profound scientific significance and wide-ranging application value. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 Here is a SEM image of the SiO2 prepared in Example 1;

[0024] Figure 2 The image shows a SEM image of the Co / CN@SiO2 composite material prepared in Example 1.

[0025] Figure 3 The amount of Co(NO3)2·6H2O in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 1-4 affects the degradation rate of bisphenol A.

[0026] Figure 4 The amount of Co(NO3)2·6H2O in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 1-4 is used to determine the k-value of the degradation of bisphenol A.

[0027] Figure 5 The effect of the amount of SiO2 in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 5-8 on the degradation rate of bisphenol A;

[0028] Figure 6 The amount of SiO2 in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 5-8 affects the degradation k-value of bisphenol A.

[0029] Figure 7 The effect of reaction time on the degradation rate of bisphenol A in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 9-12;

[0030] Figure 8 The reaction time as a factor of k in the degradation of bisphenol A in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 9-12;

[0031] Figure 9 The effect of calcination temperature on the degradation rate of bisphenol A in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 13-16;

[0032] Figure 10 The values ​​of calcination temperature on the degradation of bisphenol A in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 13-16 are shown.

[0033] Figure 11 The degradation rates of bisphenol A by different catalyst systems;

[0034] Figure 12 The k-values ​​represent the degradation of bisphenol A by different catalyst systems;

[0035] Figure 13 The degradation rates of bisphenol A by different concentrations of PMS;

[0036] Figure 14 The k-values ​​for the degradation of bisphenol A by different concentrations of PMS;

[0037] Figure 15 The degradation rate of bisphenol A at different pH values;

[0038] Figure 16 The k-values ​​represent the degradation of bisphenol A at different pH values;

[0039] Figure 17 The degradation rates of different pollutants;

[0040] Figure 18 The k-values ​​represent the degradation values ​​of different pollutants;

[0041] Figure 19 The degradation performance of bisphenol A by the Co / CN@SiO2+PMS system;

[0042] Figure 20 The k-value represents the degradation of bisphenol A in the presence of a free radical scavenger.

[0043] Figure 21 The degradation performance of bisphenol A in actual water samples;

[0044] Figure 22 The value of k represents the degradation of bisphenol A in the actual water sample. Detailed Implementation

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0046] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0047] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0048] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0049] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0050] Unless otherwise specified, "room temperature" in this invention refers to 25±2℃.

[0051] The experimental reagents and instruments used in the following embodiments of the present invention are shown in Tables 1 and 2.

[0052] Table 1. Main reagents used in the experiment

[0053] Experimental reagents Chemical formula Purity / specification Manufacturer Tetraethyl orthosilicate Si(OC2H5)4 AR Aladdin reagent (Shanghai) Co., Ltd. Ammonia [NH3.H2O] AR Aladdin reagent (Shanghai) Co., Ltd. Dopamine [C8H 11 NO2]]> AR Aladdin reagent (Shanghai) Co., Ltd. Cobalt nitrate hexahydrate Co(NO3)2-6H2O AR Aladdin reagent (Shanghai) Co., Ltd. Potassium peroxymonosulfate H3K5O 18 S4]] AR Aladdin reagent (Shanghai) Co., Ltd. Anhydrous methanol CH3OH AR National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0054] Table 2. Instruments and equipment used in the experiment

[0055] Equipment name Equipment model Instrument manufacturer Electronic analytical balance HZ-104135S Fujian Technology Co., Ltd. Laboratory ultrapure water machine UPT-1-10T Sichuan Uptop Ultrapure Technology Co., Ltd. Tabletop high-speed centrifuge H3-18K Hunan Kecheng Instrument Co., Ltd. Ultrasonic cleaner KQ-500ES Kunshan Ultrasonic Instrument Co., Ltd. Digital constant temperature magnetic heating stirrer KX-85-2A Jiangsu Kexi Instrument Co., Ltd. UV-visible spectrophotometer UV8000A Shanghai Yuanchi Instrument Co., Ltd. Electric heating constant temperature air drying oven DHG-9036A Shanghai Jinghong Experimental Equipment Co., Ltd. High-resolution cold field emission scanning electron microscope Hitachi SU8010 Hitachi, Japan Vacuum tube furnace MSG1200-50S-LV Shanghai Jiao Heng Furnace Co., Ltd.

[0056] The technical solution of the present invention will be further illustrated by the following embodiments.

[0057] Example 1

[0058] A method for preparing a Co / CN@SiO2 composite material, comprising the following steps:

[0059] 1) First, set up the oil bath apparatus, and add 225 mL of ethanol, 150 mL of ammonia water and 30 mL of distilled water to a 500 mL round-bottom flask. Seal the flask with a glass stopper, turn on the heating and stirring switch and when the temperature reaches 60℃, quickly add 17.5 mL of tetraethyl orthosilicate to the flask and react for 120 minutes. When the temperature cools to room temperature, centrifuge three times each at 8000 rpm for 10 minutes with anhydrous ethanol and deionized water, and collect the white precipitate. Place it in a vacuum chamber and dry it at 70℃ for 24 hours to obtain SiO2. Repeat the experiment to obtain a large amount of SiO2 for later use.

[0060] 2) Weigh 0.618 g of Co(NO3)2·6H2O and 1.0 g of SiO2 and 50 mL of a pre-prepared pH=8 buffer solution using an electronic balance and add them to a 100 mL round-bottom flask. After stirring magnetically for 30 minutes, add 0.0216 g of dopamine and react at room temperature for 18 hours to obtain a dark brown product. Then wash the product twice with deionized water and once with anhydrous ethanol at 8000 rpm, centrifuging for 10 minutes each time. Transfer the centrifuged sample to a crucible and place it in a tube furnace. Purge with argon gas and calcine at 600℃ for 2 hours to obtain the Co / CN@SiO2 composite material.

[0061] Figure 1 The image shows a SEM image of SiO2 prepared in Example 1. Figure 1 As can be seen, silica materials have uniform spherical particles, smooth surfaces, and good dispersibility, indicating that they are suitable as carrier materials for further functionalization or the preparation of composite materials.

[0062] Figure 2 The image shows a SEM image of the Co / CN@SiO2 composite material prepared in Example 1. Figure 2 It can be seen from the data that the Co-based composite material consists of spherical particles.

[0063] Comparative Example 1

[0064] Same as Example 1, except that the amount of Co(NO3)2·6H2O is adjusted from 0.618g to 4.94g.

[0065] Comparative Example 2

[0066] Same as Example 1, except that the amount of Co(NO3)2·6H2O is adjusted from 0.618g to 2.47g.

[0067] Comparative Example 3

[0068] Same as Example 1, except that the amount of Co(NO3)2·6H2O is adjusted from 0.618g to 1.235g.

[0069] Comparative Example 4

[0070] Same as Example 1, except that the amount of Co(NO3)2·6H2O is adjusted from 0.618g to 0.309g.

[0071] Comparative Example 5

[0072] Same as Example 1, except that the SiO2 content is adjusted from 1.0g to 2.0g.

[0073] Comparative Example 6

[0074] Same as Example 1, except that the SiO2 content is adjusted from 1.0g to 0.5g.

[0075] Comparative Example 7

[0076] Same as Example 1, except that the SiO2 content is adjusted from 1.0g to 0.25g.

[0077] Comparative Example 8

[0078] Same as Example 1, except that the SiO2 content is adjusted from 1.0g to 0.125g.

[0079] Comparative Example 9

[0080] Same as Example 1, except that the reaction time in step 2) is changed from 18 hours at room temperature to 6 hours.

[0081] Comparative Example 10

[0082] Same as Example 1, except that the reaction time in step 2) is changed from 18 hours at room temperature to 12 hours.

[0083] Comparative Example 11

[0084] Same as Example 1, except that the reaction time in step 2) is changed from 18 hours at room temperature to 24 hours.

[0085] Comparative Example 12

[0086] Same as Example 1, except that the reaction time in step 2) is changed from 18 hours at room temperature to 48 hours.

[0087] Comparative Example 13

[0088] Same as Example 1, except that the calcination temperature in step 2) is adjusted from 600℃ to 400℃.

[0089] Comparative Example 14

[0090] Same as Example 1, except that the calcination temperature in step 2) is adjusted from 600℃ to 500℃.

[0091] Comparative Example 15

[0092] Same as Example 1, except that the calcination temperature in step 2) is adjusted from 600℃ to 700℃.

[0093] Comparative Example 16

[0094] Same as Example 1, except that the calcination temperature in step 2) is adjusted from 600℃ to 800℃.

[0095] Application Example 1

[0096] The Co / CN@SiO2 composite materials prepared in Examples 1 and 1-4 were used as catalysts for the degradation of organic matter. The effect of the amount of Co(NO3)2·6H2O in the catalyst on the degradation system was investigated. The specific steps were as follows: 5 20 mL portions of 20 mg / L bisphenol A solution were taken, and the pH of the solution in the beakers was adjusted to 4.50 using HCl and NaOH. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated in the reaction system for 2 minutes to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system and the reaction time was started. The reaction was continued for 5 minutes. Every minute, 1 mL of supernatant was transferred from the reaction system and injected into a container containing 1 mL of saturated methanol solution of sodium thiosulfate to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k-value of catalytic degradation was calculated accordingly.

[0097] Figure 3 The amount of Co(NO3)2·6H2O in the Co / CN@SiO2 composite materials prepared in Examples 1 and Comparative Examples 1-4 affects the degradation rate of bisphenol A. Figure 4 The amount of Co(NO3)2·6H2O in the Co / CN@SiO2 composite materials prepared in Examples 1 and Comparative Examples 1-4 was used to determine the k-value of bisphenol A degradation. Figure 3 and Figure 4 The presented data clearly show that as the amount of Co(NO3)2·6H2O added to the catalyst increases, its degradation efficiency exhibits a trend of first increasing and then decreasing. Specifically, when the amount of Co(NO3)2·6H2O increases from 0.309 g to 4.94 g, the degradation rate constant k of bisphenol A first increases from 1.1929 min... -1 Rising to 1.5971 min -1 It then decreased to 0.4441 min.-1 This change may be attributed to the fact that as the amount of Co(NO3)2·6H2O increases, the number of active sites on the catalyst increases, thereby promoting the degradation reaction and increasing the degradation rate. When the dosage reaches an optimal value, the active sites of the catalyst can fully contact the reactants, at which point the degradation rate reaches its maximum. However, when the dosage exceeds this optimal value, catalyst particles may agglomerate, leading to a reduction in effective active sites and consequently a decrease in the degradation rate.

[0098] Application Example 2

[0099] The Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 5-8 were used as catalysts for the degradation of organic matter. The effect of the amount of SiO2 in the catalyst on the degradation system was investigated. The specific steps were as follows: 5 20 mL portions of 20 mg / L bisphenol A solution were taken, and the pH of the solution in the beakers was adjusted to 4.50 using HCl and NaOH. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated in the reaction system for 2 minutes to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system and the reaction time was started. The reaction was continued for 5 minutes. Every minute, 1 mL of supernatant was transferred from the reaction system and injected into a container containing 1 mL of saturated methanol solution of sodium thiosulfate to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k-value of catalytic degradation was calculated accordingly.

[0100] Figure 5 The effect of the amount of SiO2 in the Co / CN@SiO2 composite materials prepared in Examples 1 and Comparative Examples 5-8 on the degradation rate of bisphenol A was investigated. Figure 6 The degradation rate constant (k) of bisphenol A was determined by the amount of SiO2 added in the Co / CN@SiO2 composite materials prepared in Examples 1 and 5-8. The experimental results showed that different amounts of SiO2 catalyzed the degradation of bisphenol A. Specifically, when the amount of SiO2 added increased from 0.125 g to 1.0 g, the degradation rate constant (k) of bisphenol A increased from 0.5064 min / min. -1 Increased to 1.5971min -1 This improvement can be attributed to the high specific surface area and porous structure of silica. Appropriately increasing its addition can introduce more active sites to the catalyst, thereby promoting the adsorption and degradation reactions of the reactants and improving catalytic efficiency. However, when the amount of SiO2 added continued to increase from 1.0 g to 2.0 g, the reaction rate decreased, and the k-value dropped to 0.6614 min. -1 This indicates that excessive silica may cover the active sites of the catalyst, hindering effective contact between reactants and active components, thereby reducing catalytic efficiency.

[0101] Application Example 3

[0102] The Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 9-12 were used as catalysts for the degradation of organic matter. The effect of reaction time on the degradation system was investigated. The specific steps were as follows: Five 20 mL portions of 20 mg / L bisphenol A solution were taken. The pH of the solution in the beakers was adjusted to 4.50 using HCl and NaOH. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated in the reaction system for 2 minutes to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system and the timer was started. The reaction lasted for 5 minutes. Every minute, 1 mL of supernatant was transferred from the reaction system and injected into a container containing 1 mL of saturated methanol solution of sodium thiosulfate to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k value of catalytic degradation was calculated accordingly.

[0103] Figure 7 The effect of reaction time on the degradation rate of bisphenol A in the Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 9-12 is shown. Figure 8 The reaction time as a factor of k in the degradation of bisphenol A in the Co / CN@SiO2 composite materials prepared in Examples 1 and Comparative Examples 9-12; according to Figure 7 , 8 It can be clearly observed that the degradation rate is highest when the reaction time of the synthetic catalyst is 18 hours. When the reaction time of the synthetic catalyst is increased from 6 hours to 18 hours, the degradation k value of bisphenol A decreases from 0.7979 min. -1 Increased to 1.5971 min -1 This phenomenon may be due to the high initial reactant concentration, which gives the catalyst more opportunities to interact with the reactants, thus increasing the degradation rate. However, when the reaction time of the synthesized catalyst is extended from 18 hours to 48 hours, the degradation rate constant k of bisphenol A shows a gradual decreasing trend, from 1.5971 min. -1 It dropped to 0.7053 min. -1 This phenomenon may be attributed to the gradual decrease in reactant concentration during the reaction process, which leads to a reduction in the effective contact between the catalyst and the reactants, thereby reducing the degradation efficiency.

[0104] Application Example 4

[0105] The Co / CN@SiO2 composite materials prepared in Example 1 and Comparative Examples 13-16 were used as catalysts for the degradation of organic matter. The effect of calcination temperature on the degradation system was investigated. The specific steps were as follows: 5 20 mL portions of 20 mg / L bisphenol A solution were taken, and the pH of the solution in the beakers was adjusted to 4.50 using HCl and NaOH. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated in the reaction system for 2 minutes to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system and the reaction time was started. The reaction continued for 5 minutes. Every minute, 1 mL of supernatant was transferred from the reaction system and injected into a container containing 1 mL of sodium thiosulfate in methanol to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k-value of catalytic degradation was calculated accordingly.

[0106] Figure 9 The effect of calcination temperature on the degradation rate of bisphenol A in the Co / CN@SiO2 composite materials prepared in Examples 1 and Comparative Examples 13-16 is shown. Figure 10 The calcination temperature (k-value) of the Co / CN@SiO2 composite materials prepared in Examples 1 and 13-16 is used to determine the degradation k-value of bisphenol A. Figure 9 , 10 As shown, as the temperature increases from 400℃ to 600℃, the degradation rate constant k of the degradation system increases from 1.0222 min⁻¹. -1 Increased to 1.5971 min -1 However, as the temperature continued to rise from 600℃ to 800℃, the k value decreased from 1.5971 min. -1 Decreased to 1.2253 min -1 This phenomenon may be attributed to the fact that a moderate increase in temperature can provide more reactant molecules with the energy needed to overcome the activation energy, thereby promoting an increase in the reaction rate; however, excessively high temperatures may damage the catalyst structure, causing a reduction in the number of active sites or deactivation.

[0107] Application Example 5

[0108] The Co / CN@SiO2 composite material prepared in Example 1 was used as a catalyst for the degradation of organic matter. The influence of reaction system variables on the degradation system was investigated. The specific steps were as follows: Three 20 mL aliquots of 20 mg / L bisphenol A solution were taken. The pH of the solution in the beaker was adjusted to 4.50 using HCl and NaOH. 8 mg of the catalyst prepared in Example 1 was weighed using an electronic balance and added to one of the 20 mg / L bisphenol A solutions. The catalyst was sonicated in the reaction system for 2 min to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system, and the reaction was started. The reaction lasted for 5 minutes. Every minute, 1 mL of supernatant was transferred from the reaction system and injected into a container containing 1 mL of saturated methanol solution of sodium thiosulfate to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k value of catalytic degradation was calculated accordingly. One of the other two aliquots was treated without catalyst, and the other without PMS (16 g / L). The other steps were the same as the first aliquot.

[0109] Figure 11 The degradation rates of bisphenol A by different catalyst systems are shown. Figure 12 The k-values ​​represent the degradation rates of bisphenol A by different catalyst systems; for example... Figure 11 , 12 As shown, the degradation rate constant k values ​​for bisphenol A in the single catalyst system and the single PMS system are 0.0146 min. -1 0.0176min -1 The low degradation rate reveals that the binding ability of the catalyst to bisphenol A and PMS to bisphenol A is weak in both systems. This result further confirms that the Co-based composite catalyst synthesized in Example 1 of this invention can significantly improve the degradation rate of bisphenol A. For this polymer system, the Co-based composite catalyst exhibits excellent catalytic degradation performance.

[0110] Application Example 6

[0111] The Co / CN@SiO2 composite material prepared in Example 1 was used as a catalyst for the degradation of organic matter. The effect of PMS concentration on the degradation system was investigated. The specific steps were as follows: Five 20 mL aliquots of 20 mg / L bisphenol A solution were taken. The pH of the solution in the beakers was adjusted to 4.50 using HCl and NaOH. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated in the reaction system for 2 min to achieve uniform dispersion. Then, 1 mL of prepared PMS solutions with concentrations of (14 g / L, 15 g / L, 16 g / L, 17 g / L, and 18 g / L) were added to the reaction system, and the reaction was started. The reaction lasted for 5 minutes. Every minute, 1 mL of supernatant was transferred from the reaction system and injected into a container containing 1 mL of saturated methanol solution of sodium thiosulfate to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k-value of catalytic degradation was calculated accordingly.

[0112] Figure 13 The degradation rates of bisphenol A by different concentrations of PMS are shown. Figure 14 The k-values ​​for the degradation of bisphenol A by different concentrations of PMS; based on Figure 13 , 14 The data show that, within the range of PMS concentration increasing from 14 g / L to 16 g / L, the degradation efficiency of bisphenol A exhibits an increasing trend, specifically, the degradation rate constant k increases from 0.7580 min⁻¹. -1 Increased to 1.5971 min -1 This may be because at low PMS concentrations, the amount of sulfate radicals (SO42-) generated increases with increasing PMS concentration. - The increased number of ·) and hydroxyl radicals (·OH) promotes the degradation of bisphenol A, leading to an increase in the degradation rate. However, when the PMS concentration continues to increase from 16 g / L to 18 g / L, the degradation rate constant k of bisphenol A decreases from 1.5971 min. -1 Reduced to 1.0315 min -1 This phenomenon may be attributed to the fact that when the PMS concentration is too high, free radicals react with each other, resulting in a decrease in the number of effective free radicals, thereby reducing the degradation efficiency of bisphenol A.

[0113] Application Example 7

[0114] The Co / CN@SiO2 composite material prepared in Example 1 was used as a catalyst for the degradation of organic matter. The effect of pH on the degradation system was investigated. The specific steps were as follows: 20 mL of bisphenol A solution was placed in a beaker, and the pH of the solution was adjusted using HCl and NaOH to achieve pH values ​​of 4.50, 6.09, 7.97, and 9.68, respectively. 8 mg of catalyst was added to each solution, and the beaker was then ultrasonically vibrated for 2 minutes to ensure uniform dispersion of the catalyst. Then, 1 mL of prepared PMS (16 g / L) was added to the solution using a pipette to initiate the catalytic oxidation reaction. At 0, 0.5, 1, 1.5, 2, 2.5, and 3 minutes, 1 mL of the supernatant was injected into a container containing 1 mL of sodium thiosulfate in a methanol-saturated solution to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k-value for catalytic degradation was calculated accordingly.

[0115] Figure 15 The degradation rate of bisphenol A at different pH values ​​was calculated. Figure 16 The k-values ​​represent the degradation of bisphenol A at different pH values; based on Figure 15 , 16 The data show that the degradation rate of bisphenol A decreases with increasing pH. At pH values ​​of 4.5, 6.09, 7.97, and 9.68, the degradation rate constant is 1.5971 min⁻¹, respectively. -1 0.6219min -1 0.6023min -1 0.5035min -1 This is mainly due to the combined effects of factors such as changes in catalyst surface charge, free radical generation and transformation, PMS stability, and the interaction between the catalyst and PMS.

[0116] Application Example 8

[0117] The Co / CN@SiO2 composite material prepared in Example 1 was used as a catalyst for the degradation of organic matter. The effects of different degradants on the degradation system were investigated. The specific steps were as follows: 20 mL of each of the 20 mg / L concentrations of Coomassie Brilliant Blue, Methyl Orange, and Rhodamine B were weighed using an electronic balance, and 8 mg of catalyst was added to the reaction system respectively. The catalyst was sonicated in the reaction system for 2 minutes to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system using a pipette, and the reaction was started. The reaction lasted for 5 minutes. Every minute, 1 mL of the supernatant was transferred from the reaction system and injected into a container containing 1 mL of a methanol-saturated solution of sodium thiosulfate to terminate the reaction. The absorbance of Coomassie Brilliant Blue, Methyl Orange, and Rhodamine B in the solution was measured using a UV-Vis spectrophotometer, and the k-value for catalytic degradation was calculated accordingly.

[0118] Figure 17 For the degradation rates of different pollutants, Figure 18 The degradation k-values ​​for different pollutants; based on Figure 17 , 18 The data shown indicate that the catalyst prepared in Example 1 exhibits a degradation rate constant k of 0.4738 min for methyl orange, rhodamine B, and Coomassie Brilliant Blue. -1 0.8899min -1 and 0.5899min -1 This result indicates that the catalyst prepared in Example 1 of this invention has a certain degradation ability for various pollutants, and after reacting with PMS, it can stably and rapidly degrade organic dyes such as methyl orange, rhodamine B, and Coomassie brilliant blue.

[0119] Application Example 9

[0120] To determine the contribution of reactive oxygen species (ROS) generated in the Co / CN@SiO2+PMS system to pollutant removal, this invention conducted free radical scavenging experiments. Generally, reactive oxygen species such as SO4· - Free radicals, ·OH radicals, O2· - free radicals and non-free radicals 1 O2 is the primary cause of organic pollutant degradation in PMS catalytic systems; therefore, this invention selects methanol as the SO4·2·4 ... - TBA was selected as a quencher for ·OH radicals. The specific steps were as follows: According to calculations, when tert-butanol / PMS = 100 (molar ratio), the amount of tert-butanol used was 0.249 mL; when tert-butanol / PMS = 1000 (molar ratio), the amount of tert-butanol used was 2.49 mL. Two 20 mL portions of 20 mg / L bisphenol A solution were taken, and 0.249 mL and 2.49 mL of tert-butanol were added respectively, and the mixture was sonicated for 2 min. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated in the reaction system for 2 minutes to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system using a pipette, and the reaction was started. The reaction was continued for 5 minutes. Every minute, 1 mL of supernatant was transferred from the reaction system and injected into a container containing 1 mL of sodium thiosulfate in a methanol saturated solution to terminate the reaction. The area of ​​bisphenol A in the solution was determined by liquid chromatography, and the k value for catalytic degradation was calculated accordingly.

[0121] Calculations show that when the methanol / PMS ratio is 100, the methanol dosage is 0.105 mL; when the methanol / PMS ratio is 1000, the methanol dosage is 1.05 mL. Two 20 mL aliquots of 20 mg / L bisphenol A solution were taken, and 0.105 mL and 1.05 mL of methanol were added respectively. The solutions were sonicated for 2 min. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated for 2 minutes to achieve uniform dispersion in the reaction system. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system, and the reaction was started. The reaction was continued for 5 minutes. Every minute, 1 mL of the supernatant was transferred from the reaction system and injected into a container containing 1 mL of a methanol-saturated solution of sodium thiosulfate to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k-value for catalytic degradation was calculated accordingly.

[0122] Furthermore, this invention also selects p-benzoquinone (P-BQ) as O2· - Scavenger, furfural (FFA) as a non-free radical scavenger 1 The O2 scavenger uses the following steps: Based on calculations, when the p-benzoquinone / PMS ratio is 40 (molar ratio), the amount of p-benzoquinone used is 0.112 g; when the p-benzoquinone / PMS ratio is 4 (molar ratio), the amount of p-benzoquinone used is 0.0112 g. Take two 20 mL portions of 20 mg / L bisphenol A solution, add 0.112 g and 0.0112 g of p-benzoquinone respectively, and sonicate for 2 min. Weigh 8 mg of catalyst using an electronic balance and add it to the reaction system. Sonicate the catalyst in the reaction system for 2 minutes to achieve uniform dispersion. Then, use a pipette to add 1 mL of prepared PMS (16 g / L) to the reaction system and start timing. The reaction continues for 5 minutes. Every minute, transfer 1 mL of supernatant from the reaction system into a container containing 1 mL of sodium thiosulfate in a methanol-saturated solution to terminate the reaction. Measure the area of ​​bisphenol A in the solution using liquid chromatography and calculate the k-value for catalytic degradation.

[0123] Calculations show that when the furfural / PMS ratio is 10, the amount of furfural used is 0.0225 mL; when the furfural / PMS ratio is 100, the amount of furfural used is 0.225 mL. Two 20 mL aliquots of 20 mg / L bisphenol A solution were taken, and 0.0225 mL and 0.225 mL of furfural were added respectively, followed by sonication for 2 min. 8 mg of catalyst was weighed using an electronic balance and added to the reaction system. The catalyst was sonicated for 2 minutes to achieve uniform dispersion in the reaction system. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system, and the reaction was started. The reaction continued for 5 minutes. Every minute, 1 mL of the supernatant was transferred from the reaction system and injected into a container containing 1 mL of sodium thiosulfate in a methanol-saturated solution to terminate the reaction. The area of ​​bisphenol A in the solution was determined using liquid chromatography, and the k-value for catalytic degradation was calculated accordingly.

[0124] Figure 19 The degradation performance of bisphenol A by the Co / CN@SiO2+PMS system was studied. Figure 20 The k-value represents the degradation of bisphenol A in the presence of a free radical scavenger; [The remaining text appears to be a fragmented and incomplete sentence, possibly due to OCR errors. A more coherent translation would require the full context.] Figure 19 , Figure 20 It can be seen that when the molar ratio of MeOH / PMS and TBA / PMS is both 100, the degradation rate constants increase from 0.5118 min⁻¹ to 100. -1 It decreased to 0.2266 min. -1 and 0.4229min -1 When the TBA / PMS molar ratio increased to 1000, the rate constant decreased to 0.1196 min. -1 When the molar ratio of MeOH / PMS in the system increased to 1000, the degradation rate constant was 0.1157 min. -1 The above experimental results show that ·OH and SO4· - Both exist simultaneously in the Co / CN@SiO2+PMS system, and both contribute to the removal of bisphenol A, but SO4· - The contribution of bisphenol A removal is greater than that of ·OH. In the Co / CN@SiO2+PMS system with an FFA / PMS molar ratio of 10, the degradation rate constant k of bisphenol A decreased to 0.3037 min. -1 When the concentration of FFA in the system increased to FFA / PMS = 100, the degradation rate constant of bisphenol A decreased to 0.0299 min. -1 ,show 1 O2 also participated in the reaction. Undoubtedly, SO4· - ·OH and 1The contribution of O2 to the degradation of bisphenol A is not negligible. However, regardless of whether the P-BQ / PMS molar ratio was 4 or 40, the degradation of bisphenol A showed a very significant inhibitory effect, and the degradation rate constant decreased from 0.5118 to 0.0446 min, respectively. -1 and 0.0207min -1 It can be said that it hardly degrades, indicating that O2· - It plays a major role in the degradation of bisphenol A in the Co / CN@SiO2+PMS system. Based on the above analysis, it is inferred that SO4·2 ... - ·OH, O2· - and 1 O2 also participates in the removal of bisphenol A.

[0125] Application Example 10

[0126] To further verify the practical application of the catalyst synthesized in Example 1, a certain amount of bisphenol A was added to an actual wastewater sample (Fuyang) for analysis. The specific steps are as follows: A 20 mg / L bisphenol A solution was prepared using the actual wastewater sample diluted 200 times as a solvent. Three 20 mL portions of the prepared bisphenol A solution were taken, and 8 mg of catalyst was weighed using an electronic balance and added to one of the reaction systems. The catalyst was sonicated in the reaction system for 2 min to achieve uniform dispersion. Then, 1 mL of prepared PMS (16 g / L) was added to the reaction system using a pipette, and the reaction was started. The reaction lasted for 5 min. Every 1 min, 1 mL of the supernatant was transferred from the reaction system and injected into a container containing 1 mL of a methanol-saturated solution of sodium thiosulfate to terminate the reaction. The area of ​​bisphenol A in the solution was measured using liquid chromatography, and the k-value for catalytic degradation was calculated accordingly. One of the other two bisphenol A solutions was treated without catalyst, and the other without PMS (16 g / L). The other steps were the same as the first treatment.

[0127] Figure 21 This demonstrates the degradation performance of bisphenol A in actual water samples. Figure 22 The value of k represents the degradation of bisphenol A in the actual water sample; based on Figure 21 , 22 As shown, even in complex real-world wastewater, the catalyst can effectively activate PMS within 5 minutes, achieving almost 100% removal of bisphenol A. In actual water bodies, the rate constant k for catalytic activation of PMS to degrade bisphenol A can be observed to reach 0.7141 min. -1 It is 40.8 times and 49.2 times higher than PMS alone and catalyst alone, respectively.

[0128] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A Co / CN@SiO2 composite material, characterized in that, The Co / CN@SiO2 composite material comprises a silicon dioxide carrier, cobalt nanoparticles loaded on the carrier, and a carbon-nitrogen layer coated on the surface of the cobalt nanoparticles.

2. A method for preparing the Co / CN@SiO2 composite material according to claim 1, characterized in that, The method comprises the following steps: ethanol, ammonia water and distilled water are mixed, heated to 60 DEG C, and then tetraethyl orthosilicate is added for heating reaction, and after centrifugation, washing and drying, a silicon dioxide carrier is obtained; the cobalt nitrate hexahydrate, the silicon dioxide carrier and the buffer solution are mixed, stirred, and then dopamine is added, and the reaction is carried out at room temperature to obtain a black-brown product, which is washed and then calcined in an inert atmosphere to obtain the Co / CN@SiO2 composite material.

3. The production method according to claim 2, characterized by, The volume ratio of the ethanol, ammonia water and tetraethyl orthosilicate is 225:150:17.

5.

4. The production method according to claim 2, characterized by, The heating reaction is carried out for 120 minutes.

5. The preparation method according to claim 2, characterized in that, The mass ratio of the cobalt nitrate hexahydrate, the silicon dioxide carrier and the dopamine is 0.618:1.0:0.0216.

6. The preparation method according to claim 2, characterized in that, The reaction is carried out at room temperature for 18 hours.

7. The preparation method according to claim 2, characterized in that, The calcination treatment is calcination at 600 DEG C for 2 hours.

8. The Co / CN@SiO2 composite material according to claim 1 is applied to catalytic degradation of organic dyes.

9. Use according to claim 8, characterized in that, The organic dyes include bisphenol A, rhodamine B, methyl orange or coomassie brilliant blue.

10. Use according to claim 8, characterized in that, The catalytic degradation is carried out in the presence of a peroxymonosulfonate, and the concentration of the peroxymonosulfonate is 16 g / L, and the pH value of the reaction system is 4.5.

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