Preparation method and application of iron-zinc co-doped graphite-like wastewater self-purification catalyst

Abstract

The application provides a preparation method of an iron-zinc co-doped graphite-like wastewater self-purification catalyst and application thereof, and the method comprises the following steps: dissolving iron metal salt and zinc metal salt in deionized water, adjusting pH to form a solution A by using ammonia water, adding melamine to form a dispersion B after stirring, then adding an organic complexing agent, stirring, and then stirring to dryness in a water bath, and then drying in a blast drying oven, and finally uniformly grinding the obtained product and sodium bicarbonate, and then calcining, and grinding the obtained black solid to obtain the Fe 0 -Fe x C y @C catalyst. The preparation method is simple, requires low equipment, and the prepared Fe 0 -Fe x C y @C catalyst can effectively and rapidly remove organic pollutants such as bisphenols, ciprofloxacin and sulfamethoxazole in water without adding an oxidant; has excellent removal effect on difficult biodegradable organic pollutants at neutral room temperature, has high stability, and has very low metal ion dissolution rate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment catalyst preparation, and particularly relates to a preparation method of an iron-zinc co-doped graphene-like wastewater self-purification catalyst and application thereof. BACKGROUND

[0002] Water pollution problems are increasingly serious, posing a great threat to human health and the ecological environment. In addition to traditional pollutants, some new pollutants have attracted widespread attention due to their unique properties and potential hazards. As typical new water pollutants, endocrine disruptors and antibiotics have become the focus of research and governance due to their widespread presence in the environment and potential hazards.

[0003] To address this challenge, advanced oxidation technologies (AOPs) have emerged as an efficient wastewater treatment method. AOPs can effectively degrade a variety of organic pollutants by generating highly oxidizing hydroxyl radicals ( · OH). Common AOPs include ozone oxidation (O3), photocatalytic oxidation combined with hydrogen peroxide (H3O3) and ultraviolet light (UV), Fenton reaction, and electrochemical oxidation. These technologies perform well in treating refractory organic matter, but also have significant limitations, particularly high energy consumption and the need for chemical additives, which increases operating costs and the risk of secondary pollution. Therefore, technology that activates dissolved oxygen in water through the construction of a strong electric field on the surface of the catalyst to drive the self-degradation of pollutants on the catalyst surface has gradually attracted attention. It does not require the addition of other chemicals, can treat organic pollutants in wastewater at low energy consumption, and reduces wastewater treatment costs. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of existing advanced oxidation technologies and provide a preparation method of an iron-zinc co-doped graphene-like wastewater self-purification catalyst and application thereof.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] On the one hand, the present application provides a preparation method of an iron-zinc co-doped graphene-like wastewater self-purification catalyst, which comprises the following steps:

[0007] (1) Dissolve a certain amount of iron metal salt and zinc metal salt in deionized water, and adjust the pH of the solution with ammonia water to form solution A;

[0008] (2) Add a certain amount of melamine to solution A, and after stirring for 30 min, form dispersion liquid B;

[0009] (3) Add a certain amount of organic complexing agent to dispersion B, stir for 1 hour, stir in a water bath at 80°C until dry, and then place in a forced-air drying oven to dry for 12 hours.

[0010] (4) Grind the product obtained in step (3) and a certain amount of sodium bicarbonate evenly and then dry it;

[0011] (5) The product obtained in step (4) was placed in a quartz jar, calcined in a tube furnace under nitrogen atmosphere, and then ground to obtain Fe. 0 -Fe x C y @C catalyst.

[0012] The preparation method of the iron-zinc co-doped graphene-based wastewater self-purification catalyst of this invention can be classified into a two-step synthesis method: the first step is a simple heating and stirring precipitation method, and the second step is a calcination method. The prepared Fe... 0 -Fe x C y @C catalysts exhibit excellent catalytic performance in the degradation of organic pollutants in water.

[0013] Preferably, in step (1), the iron metal salt is one of ferric chloride hexahydrate, ferric chloride, ferric nitrate nonahydrate, ferric acetate, ferric sulfate, and ferric acetylacetone; the zinc metal salt is one of zinc nitrate, zinc chloride, zinc acetate, and zinc sulfate; and the pH of the solution is adjusted to 7-10, preferably 9.

[0014] Furthermore, the iron metal salt is ferric chloride hexahydrate, and the zinc metal salt is anhydrous zinc chloride; the amount of ferric chloride hexahydrate is 0.5-6 mmol, and the amount of anhydrous zinc chloride is 2-10 mmol.

[0015] Furthermore, the amount of ferric chloride hexahydrate was 3 mmol; the amount of anhydrous zinc chloride was 6 mmol.

[0016] Preferably, in step (2), the mass of melamine is 3-15g, and more preferably 6g.

[0017] Preferably, in step (3), the organic complexing agent includes one of dopamine hydrochloride, tannic acid, pyrazole and glucosamine hydrochloride, with a mass of 0.5-5g.

[0018] Furthermore, in step (3), the organic complexing agent is glucosamine hydrochloride, with a mass of 1.2g.

[0019] Preferably, in step (4), the mass of sodium bicarbonate is 1-6g, preferably 4g.

[0020] Preferably, in step (5), the tube furnace has a heating rate of 5℃ / min, a holding temperature of 500-900℃, preferably 900℃, and a residence time of 2-5 hours, preferably 2 hours.

[0021] The application also provides a Fe 0 -Fe x C y @C catalyst prepared by any of the above methods.

[0022] The Fe 0 -Fe x C y @C catalyst prepared by the above method is a black solid powder; its microstructure is a bamboo joint-shaped porous material. The structural composition of the catalyst is mainly nitrogen-doped graphene-coated iron-zinc metal; the metal of the catalyst of the application is tightly coated by the nitrogen-doped graphene framework, and the metal content on the surface of the material can be detected, which makes the iron-zinc metal catalytic performance more stable and not easy to dissolve in the water body. The material has a large specific surface area and a large number of voids, and the water solution enters the material inside through the voids to contact the iron-zinc metal to occur interface reaction.

[0023] In another aspect, the application also provides a use of a Fe 0 -Fe x C y @C catalyst prepared according to the above method in degrading organic pollutants in water, comprising the following steps:

[0024] The Fe 0 -Fe x C y @C catalyst is uniformly dispersed in water containing organic pollutants; the organic pollutants include at least one of bisphenols (including bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol AF, bisphenol AP, etc.), ciprofloxacin (CIP), sulfamethoxazole (SMZ).

[0025] The application has the following beneficial effects:

[0026] (1) The application provides a preparation method of an iron-zinc co-doped graphene wastewater self-purification catalyst and its application, and the preparation method is simple and requires low equipment;

[0027] (2) The Fe 0 -Fe x C y @C catalyst prepared according to the preparation method of the application, the metallic iron (including zero-valent iron and various valence states) is coated in the carbonized organic framework, mainly plays a role in regulating the internal electron distribution of the material, and the zero-valent iron serves as an active center and does not directly react with the pollutants; iron is non-consumable and has a small amount of dissolution.

[0028] (3) Fe prepared according to the preparation method provided by the present invention 0 -Fe x C y @C catalyst can effectively and quickly remove organic pollutants in water, such as bisphenols (including bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol AF, bisphenol AP, etc.), ciprofloxacin (CIP), and sulfamethoxazole (SMZ), with a removal rate of up to 80% in 5 minutes.

[0029] (4) The above Fe 0 -Fe x C y @C catalysts can effectively remove recalcitrant organic pollutants without the addition of any oxidant, exhibiting excellent stability and a very low metal ion dissolution rate. Attached Figure Description

[0030] Figure 1 Fe prepared in the embodiments of the present invention 0 -Fe x C y XRD pattern of the @C catalyst.

[0031] Figure 2 Fe prepared in the embodiments of the present invention 0 -Fe x C y High-magnification scanning electron microscope (SEM) image of the @C catalyst.

[0032] Figure 3 Fe prepared in the embodiments of the present invention 0 -Fe x C y Transmission electron microscopy (TEM) images of the @C catalyst and the distribution of C, N, O, Fe, and Zn elements within the catalyst.

[0033] Figure 4 Fe prepared in the embodiments of the present invention 0 -Fe x C y The graph shows the evaluation results of the catalytic degradation activity of the @C catalyst for three pollutants: BPA, CIP, and SMZ.

[0034] Figure 5 Fe prepared in the embodiments of the present invention 0 -Fe x C y The figure shows the evaluation results of the catalytic degradation activity of the @C catalyst for various bisphenol pollutants.

[0035] Figure 6 Fe prepared in the embodiments of the present invention 0 -Fe x Cy Figure 1 is a graph showing the results of the evaluation of the cyclic reuse activity of the Fe DETAILED DESCRIPTION

[0036] For the purpose of better illustrating the object, technical scheme and advantages of the present application, the present application will be further described in conjunction with specific examples.

[0037] Example 1

[0038] As a preparation method of the Fe

[0039] (1) 0.811 g of ferric chloride hexahydrate and 0.818 g of anhydrous zinc chloride were weighed and dissolved in 25 mL of deionized water, and the pH of the solution was adjusted to 9 with ammonia water to form solution A;

[0040] (2) 6 g of melamine was added to solution A and stirred for 30 min to form dispersion B;

[0041] (3) 1.2 g of glucosamine hydrochloride was added to dispersion B, stirred for 1 h, and then stirred to dryness in a water bath at 80°C, and then placed in a forced air drying oven for drying for 12 h;

[0042] (4) The product obtained in (3) and 4 g of sodium bicarbonate were ground and dried.

[0043] (5) The solid obtained in (4) was placed in a quartz boat, and the temperature was raised to 900°C at a rate of 5°C / min under argon atmosphere, and the temperature was kept for 2 hours. After calcination, the product was ground to obtain the Fe 0 -Fe x C y @C catalyst.

[0044] The Fe 0 -Fe x C y @C catalyst prepared in this example was characterized.

[0045] Figure 1 The XRD spectrum of the Fe 0 -Fe x C y @C catalyst prepared in Example 1. Compared with the standard card, the characteristic diffraction peaks (110), (200), (211) of elemental iron were found to be consistent.

[0046] Figure 2 The Fe 0 -Fe x C yScanning electron microscope (SEM) of C catalyst. From the figure, it can be observed that it is a bamboo-like porous material.

[0047] Figure 3 Fe 0 -Fe x C y Transmission electron microscope (TEM) of C catalyst. From the elemental analysis, it can be observed that the black nanoparticles in the figure are mainly iron, followed by zinc.

[0048] Example 2

[0049] Fe 0 -Fe x C y Application of C catalyst in degradation of organic pollutants in water, the method comprising the following steps:

[0050] 0.03 g of Fe 0 -Fe x C y C catalyst was put into 50 mL of 10 mg / L organic pollutant solution, and the degradation reaction was started under continuous stirring in a water bath at 35°C. The pollutant concentration was measured at different time points.

[0051] The organic pollutants were: bisphenol A (BPA), ciprofloxacin (CIP) and sulfamethoxazole (SMZ), respectively.

[0052] The results of the degradation rate are shown in Figure 4 Fe 0 -Fe x C y Degradation curves of C catalyst for BPA, CIP and SMZ. At 5 minutes, the removal rates of the three organic pollutants all exceeded 80%.

[0053] Example 3

[0054] Fe 0 -Fe x C y Application of C catalyst in degradation of organic pollutants in water, the method comprising the following steps:

[0055] 0.02 g of Fe 0 -Fe x C y C catalyst was put into 50 mL of 10 mg / L organic pollutant solution, and the degradation reaction was started under continuous stirring in a water bath at 35°C. The pollutant concentration was measured at different time points.

[0056] The (bisphenol) organic pollutants are: bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol AF, and bisphenol AP.

[0057] The degradation rate results are as follows Figure 5 As shown, it is Fe 0 -Fe x C y Degradation curves of bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol AF, and bisphenol AP by the @C catalyst. At 15 minutes, the removal rate of all six organic pollutants exceeded 80%.

[0058] Example 4

[0059] As an embodiment of the present invention, Fe 0 -Fe x C y The stability study of the @C catalyst in the degradation of organic pollutants in water includes the following steps:

[0060] (1) Take 0.03g of Fe prepared in Example 1 0 -Fe x C y @C catalyst was added to 50 mL of 10 mg / L BPA solution, and the degradation reaction was initiated by continuous stirring in a water bath at 35 °C.

[0061] (2) React for 30 minutes and then measure the concentration of BPA;

[0062] (3) The Fe after the reaction in step (2) 0 -Fe x C y After the @C catalyst is separated and dried, the dried catalyst is used to repeat steps (1)-(3).

[0063] Figure 6 Fe prepared in the examples 0 -Fe x C y The graph shows the activity evaluation of the @C catalyst for BPA degradation through repeated recycling. It can be observed that the catalyst's BPA degradation efficiency did not significantly decrease after continuous recycling; in six repeated experiments, the removal rate remained above 85%.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A preparation method of an iron-zinc co-doped graphenelike wastewater self-purification catalyst, characterized in that, The method is a two-step synthesis method: the first step is a heating stirring precipitation method, and the second step is a calcination method; Specifically comprising the following steps: (1) a certain amount of iron metal salt and zinc metal salt are dissolved in deionized water, and the pH of the solution is adjusted to 7-10 with ammonia water to form solution A; (2) a certain amount of melamine is added to solution A, and after stirring for 30 min, dispersion B is formed; (3) a certain amount of organic complexing agent is added to dispersion B, and after stirring for 1h, it is stirred to dryness in a water bath kettle at 80℃, and then placed in a forced air drying oven for drying for 12h; (4) the product obtained in step (3) and a certain amount of sodium bicarbonate are uniformly ground and dried; (5) the product obtained in step (4) is placed in a quartz capsule, calcined in a tube furnace under nitrogen atmosphere, and then ground to obtain a catalyst.

2. The method of claim 1, wherein, The iron metal salt in step (1) is one of ferric chloride hexahydrate, ferric chloride, ferric nitrate nonahydrate, ferric acetate, ferric sulfate and acetylacetone iron; The zinc metal salt is one of zinc nitrate, anhydrous zinc chloride, zinc acetate and zinc sulfate; The amount of substance of the ferric chloride hexahydrate is 0.5-6 mmol, and the amount of substance of the anhydrous zinc chloride is 2-10 mmol; The pH of the solution is adjusted to 9.

3. The method of claim 1, wherein, The mass of melamine in step (2) is 3-15g.

4. The method of claim 1, wherein, The organic complexing agent in step (3) includes one of dopamine hydrochloride, tannic acid, pyrazole and glucosamine hydrochloride; the mass of the organic complexing agent is 0.5-5g.

5. The method of claim 1, wherein, The mass of sodium bicarbonate in step (4) is 1-6g.

6. The method of claim 1, wherein, The temperature rising rate of the tube furnace in step (5) is 5℃ / min, the holding temperature is 500-900℃, and the residence time is 2-5 hours.

7. The catalyst prepared by the method of any one of claims 1-6.

8. The use of the catalyst of claim 7 in degrading organic pollutants in water.

9. The use of the catalyst of claim 8 in degrading organic pollutants in water, comprising the following steps: The catalyst is uniformly dispersed in water containing organic pollutants; The organic pollutants include at least one of bisphenol pollutants, ciprofloxacin, and sulfamethoxazole.

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