Preparation method and application of alumina-supported iron-aluminum co-doped graphene-like catalyst

Abstract

The present application relates to a kind of preparation method of alumina supported iron-aluminum co-doped graphene-like catalyst and its application in water treatment field.The method comprises the following steps: biomass (such as silkworm sand, corn cob, etc.) is dispersed in water to form suspension, iron salt, aluminum salt and nitrogen source (such as urea, melamine, etc.) are added in turn, after adjusting pH, alumina beads are impregnated, dried and calcined under inert atmosphere at high temperature, and the immobilized catalyst is prepared.The catalyst is loaded on alumina beads with iron-aluminum co-complexed nitrogen-doped graphene-like, with high specific surface area and active sites.The catalyst of the present application is suitable for degrading refractory organic pollutants in water (such as tetracycline, bisphenol A, ciprofloxacin), through synergistic effect with microorganisms, rapid degradation can be achieved within 30 minutes, and long-term operation stability is excellent (such as tetracycline removal rate remains 100% for 106 days).The immobilization design of catalyst facilitates separation and recovery, avoids secondary pollution, and is suitable for industrial water treatment.The supporting fixed bed reactor controls the contact reaction of pollutants and catalyst by peristaltic pump, realizes continuous and efficient treatment.The raw material cost of the present application is low, and the process is simple, with high catalytic activity and recycling property, providing an efficient and environmentally friendly solution for organic contaminated water treatment.

Description

TECHNICAL FIELD

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

[0002] Among various and complex water pollution sources, toxic and harmful refractory organic compounds have potential danger to water bodies, aquatic ecosystems and human beings. These refractory pollutants mainly include aromatic compounds such as drugs, skin care products, pesticides and endocrine disruptors. Moreover, these pollutants all contain aromatic rings, and are stable in structure and difficult to be degraded in natural environment, thereby can exist in water bodies for a long time and gradually accumulate through food chains, and finally affect human health. Therefore, it is the most important problem to develop effective technologies and methods. SUMMARY

[0003] (I) Objectives of the Invention

[0004] The primary objective of the present application is to provide a preparation method and application of an alumina-supported iron-aluminum co-doped graphene-like catalyst for synergistic water purification with microorganisms.

[0005] Another objective of the present application is to provide a solid-supported catalyst prepared by the above method, which is an iron-aluminum complexed nitrogen-doped graphene supported on alumina beads, and the catalyst exhibits good catalytic degradation activity and stability for organic pollutants.

[0006] Still another objective of the present application is to provide application of the above solid-supported catalyst in rapid degradation of refractory organic pollutants in sewage in cooperation with microorganisms.

[0007] (II) Technical Solutions

[0008] In order to achieve the above objectives, the present application adopts the following technical solutions:

[0009] On one hand, the present application provides a preparation method of an alumina-supported iron-aluminum co-doped graphene-like catalyst, comprising the following steps:

[0010] (1) dispersing biomass in deionized water, stirring for 30 min to obtain a suspension A;

[0011] (2) adding metal iron salt and aluminum salt into the suspension A, stirring uniformly and adjusting the pH of the solution to obtain an impregnation solution B;

[0012] (3) adding a nitrogen source into the suspension A, completely dissolving to form an impregnation solution C;

[0013] (4) pouring the impregnation solution C into a beaker containing alumina beads, standing at 80℃, and drying at 80℃ to obtain dried beads;

[0014] (5) The dried small balls are placed in a tube furnace and calcined under inert gas. After cooling to room temperature, the small balls are repeatedly washed with water and dried to obtain the immobilized catalyst.

[0015] Preferably, in step (1), the biomass includes one or more than two combinations of silkworm sand, corn cob, garlic straw, cyclodextrin and chitosan; the amount of biomass is 0-100 g per 1 L of water.

[0016] Preferably, in step (2), the iron salt includes ferric chloride, ferric nitrate, ferric sulfate and ferric acetate; the amount of iron salt is 0-30 mM of iron ions per 1 L of water; the aluminum salt includes aluminum chloride, aluminum nitrate and aluminum sulfate; the ratio of iron to aluminum is (1-5):1.

[0017] Preferably, in step (3), the nitrogen source includes urea, dicyanediamine, melamine and triethylenetetramine; the amount of nitrogen source is 0-100 g per 1 L of water.

[0018] Preferably, in step (4), the amount of corresponding alumina small balls is 300-900 g per 1 L of water.

[0019] Preferably, in step (5), the temperature rising rate of the tube furnace is 5℃ / min, the temperature is maintained at 500-900℃, and the residence time is 2-5 hours.

[0020] In another aspect, the application provides an alumina-supported iron-aluminum co-doped graphene-like catalyst prepared by the above preparation method.

[0021] The application also provides an application of the alumina-supported iron-aluminum co-doped graphene-like catalyst in degrading organic pollutants in water, which includes the following steps:

[0022] The alumina-supported iron-aluminum co-doped graphene-like catalyst is uniformly dispersed in water containing organic pollutants.

[0023] The organic pollutants include at least one of tetracycline (TC), bisphenol A (BPA) and ciprofloxacin (CIP).

[0024] The application also provides a fixed bed reactor for the application of the alumina-supported iron-aluminum co-doped graphene-like catalyst in degrading organic pollutants in water, which includes a fixed bed, a peristaltic pump and a plurality of liquid inlet pipes; the bottom of the fixed bed is provided with a water inlet, and the upper end is provided with a water outlet and a filler inlet; the liquid inlet pipe of the pollutants enters the fixed bed through the peristaltic pump and reacts with the catalyst, and the solution flows out from the outlet after the pollutants are degraded and treated, completing the treatment.

[0025] (Three) beneficial effects

[0026] (1) The catalyst of the present application can quickly degrade refractory organic pollutants in water within 30 min in cooperation with microorganisms.

[0027] (2) The catalyst of the present application has good stability in removing organic pollutants, and almost no metal ions are released.

[0028] (3) The catalyst of the present application belongs to a solid-supported industrial application type catalyst, which is easy to separate from water and recycle.

[0029] (4) The catalyst of the present application has low cost, and is easy to synthesize and has simple process. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The real photo of the catalyst prepared in the example.

[0031] Figure 2 The structural schematic diagram of the fixed bed reactor; wherein, 1-pollutant liquid inlet pipe, 2-peristaltic pump, 3-fixed bed, 4-water outlet, 5-catalyst.

[0032] Figure 3 The degradation effect curve of the catalyst on CIP.

[0033] Figure 4 The degradation effect curve of the catalyst on TC.

[0034] Figure 5 The degradation effect curve of the catalyst on BPA. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] Example 1

[0037] The application of a FeAl-NC-Al2O3 water purification catalyst as a fixed bed filler in degrading organic pollutants in water as an embodiment of the present application, the method comprises the following steps:

[0038] As shown in Figure 2 , a fixed bed reactor is built to treat organic pollutants in water. The operation conditions of the fixed bed reactor are as follows: the organic pollutants are transported to the fixed bed 3 by the peristaltic pump 2, the flow rate of the organic pollutants (BPA) is 1.8 mL / min, the residence time is 30 min, and the solution is neutral. FromFigure 3 It can be seen that the removal rate of CIP reached 100% in the first 46 days of operation. But as the running time goes on, the removal rate of CIP slowly decreases and gradually stabilizes, and finally the removal rate remains above 54.2%, which is likely to be the adsorption of the catalyst to CIP in the early stage, and after a period of operation, microorganisms enrich on the surface of the catalyst in the reaction, and gradually adapt to CIP, at this time microorganisms begin to play a role.

[0039] Example 2

[0040] As an application of a FeAl-NC-Al2O3 water purification catalyst as a fixed bed filler in degrading organic pollutants in water, the method comprises the following steps:

[0041] As shown in Figure 2 , a fixed bed reactor is built to treat organic pollutants in water. The operating conditions of the fixed bed reactor are as follows: organic pollutants are transported to the fixed bed 3 by peristaltic pump 2, the flow rate of organic pollutants (TC) is 1.8 mL / min, the residence time is 30 min, and the solution is neutral. It can be seen from Figure 4 that during the 106-day operation, the FeAl-NC-Al2O3 biofiltration reactor exhibits sustained and efficient degradation of TC, and the removal rate is always maintained at 100%. Combined with the previous results of removing CIP, in the early stage of operation, the removal of TC mainly depends on the adsorption of the material. However, as the reactor operates, microorganisms enrich on the surface of the catalyst in the reactor, at which point microorganisms begin to play a role.

[0042] Example 3

[0043] As an application of a FeAl-NC-Al2O3 water purification catalyst as a fixed bed filler in degrading organic pollutants in water, the method comprises the following steps:

[0044] As shown in Figure 2 , a fixed bed reactor is built to treat organic pollutants in water. The operating conditions of the fixed bed reactor are as follows: organic pollutants are transported to the fixed bed 3 by peristaltic pump 2, the flow rate of organic pollutants (CIP) is 1.8 mL / min, the residence time is 30 min, and the solution is neutral. It can be seen from Figure 5 that the degradation of BPA gradually improves with the passage of time and eventually reaches 100%.

[0045] The base material of the application has low price, low cost, convenient synthesis, simple process, and will not produce solid foreign matters such as iron mud in the reaction process, and does not need foreign matter removing device, and the small spherical particles are more suitable for practical water treatment application than the powder catalyst developed in the laboratory, and are convenient for water separation and recycling.

[0046] The above results fully show that the new type of alumina supported iron-aluminum co-doped graphene-like water purification catalyst can be applied to the treatment of actual organic contaminated water.

[0047] Although the application has been described in detail by preferred embodiments, the application is not limited to this. Any modification or replacement of the embodiments of the application made by those skilled in the art without departing from the spirit and essence of the application shall fall within the scope of the application. Any modification or replacement within the technical range disclosed by the application made by those skilled in the art shall fall within the protection scope of the application.

Claims

1. A method for preparing an alumina-supported iron-aluminum co-doped graphene catalyst, characterized in that, Includes the following steps: (1) Disperse the biomass in deionized water and stir for 30 min to obtain suspension A; (2) Add the iron and aluminum salts to suspension A, stir well and adjust the pH of the solution to obtain impregnation solution B; (3) Add the nitrogen source to the suspension A, and after it is completely dissolved, an impregnation solution C is formed; (4) Pour the impregnation solution C into a beaker containing alumina balls, let it stand at 80°C, and dry it at 80°C to obtain dried balls; (5) The dried pellets are placed in a tube furnace under inert gas and calcined. After cooling to room temperature, they are repeatedly washed with water and dried to obtain the supported catalyst.

2. The preparation method of an alumina-supported iron-aluminum co-doped graphene catalyst as described in claim 1, characterized in that: In step (1), the biomass includes one or more of silkworm excrement, corn cob, garlic straw, cyclodextrin and chitosan; the amount of biomass is 0-100 g per 1 L of water.

3. The preparation method of an alumina-supported iron-aluminum co-doped graphene catalyst as described in claim 1, characterized in that, In step (2), the iron salts include ferric chloride, ferric nitrate, ferric sulfate, and ferric acetate, and the amount of iron salts used per 1 L of water is 0~30 mM of iron ions; the aluminum salts include aluminum chloride, aluminum nitrate, and aluminum sulfate, and the ratio of iron to aluminum is (1-5):

1.

4. The method for preparing an alumina-supported iron-aluminum co-doped graphene catalyst as described in claim 1, characterized in that: In step (3), the nitrogen source includes urea, dicyandiamine, melamine and triethylenetetramine, and the mass of nitrogen source used in each 1 L of water is 0-100g.

5. The method for preparing an alumina-supported iron-aluminum co-doped graphene catalyst as described in claim 1, characterized in that, In step (4), the amount of alumina pellets used per 1 L of water is 300-900g.

6. The method for preparing an alumina-supported iron-aluminum co-doped graphene catalyst as described in claim 1, characterized in that: In step (5), the heating rate of the tubular furnace is 5℃ / min, the temperature is maintained at 500~900℃, and the residence time is 2~5 hours.

7. An alumina-supported iron-aluminum co-doped graphene catalyst prepared by any one of the preparation methods described in claims 1-6.

8. The application of the alumina-supported iron-aluminum co-doped graphene catalyst as described in claim 7 in the degradation of organic pollutants in water.

9. The application of the alumina-supported iron-aluminum co-doped graphene catalyst according to claim 8 in the degradation of organic pollutants in water, characterized in that, Includes the following steps: The alumina-supported iron-aluminum co-doped graphene catalyst as described in claim 7 is uniformly dispersed in water containing organic pollutants. The organic pollutants include at least one of tetracycline (TC), bisphenol A (BPA), and ciprofloxacin (CIP).

10. A solidified bed reactor for implementing the application described in any one of claims 8 to 9, characterized in that: It includes a solidification bed, a peristaltic pump, and several inlet pipes; the solidification bed has an inlet at the bottom and an outlet and a packing port at the top; the pollutants enter the solidification bed through the peristaltic pump and react with the catalyst, and after the pollutants are degraded, the solution flows out from the outlet water, completing the treatment.

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