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

Abstract

The invention relates to a preparation method of an alumina-loaded iron-aluminum co-doped graphene-like catalyst and application of the alumina-loaded iron-aluminum co-doped graphene-like catalyst in the field of water treatment. The method comprises the following steps: dispersing biomass (such as silkworm excrement, corncob and the like) in water to form a suspension, sequentially adding ferric salt, aluminum salt and a nitrogen source (such as urea, melamine and the like), adjusting the pH value, impregnating alumina pellets, drying, and roasting at high temperature in an inert atmosphere to prepare the immobilized catalyst. According to the catalyst, iron-aluminum co-complexed nitrogen-doped graphene is loaded on alumina pellets, and the catalyst has high specific surface area and active sites. The catalyst disclosed by the invention is suitable for degrading refractory organic pollutants (such as tetracycline, bisphenol A and ciprofloxacin) in water, can realize rapid degradation within 30 minutes through a synergistic effect with microorganisms, and is excellent in long-term operation stability (for example, the tetracycline removal rate is kept 100% for 106 days). The immobilized design of the catalyst facilitates separation and recovery, avoids secondary pollution, and is suitable for industrial water treatment. The matched curing bed reactor controls contact reaction of pollutants and a catalyst through a peristaltic pump, and continuous and efficient treatment is achieved. The method has the advantages of low raw material cost, simple process, high catalytic activity and cyclic utilization, and provides an efficient and environment-friendly solution for the treatment of organic polluted water.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and in particular relates to a preparation method and application of an alumina-supported iron-aluminum co-doped graphene-like catalyst. Background Art

[0002] China is a country with extremely scarce water resources, with per capita water resources less than a quarter of the global average. In recent decades, with the accelerated development of urban construction in my country, water pollution has become increasingly prominent, exacerbating water resource conflicts and beginning to impact sustainable development across various sectors. This increasingly severe water pollution is bound to have serious negative impacts on socioeconomic development and human health. Therefore, protecting the water environment and purifying polluted water is imperative. Among the diverse and complex sources of water pollution, toxic and hazardous, recalcitrant organic matter poses a potential threat to water bodies, aquatic ecosystems, and humans. These recalcitrant pollutants primarily include aromatic compounds, such as pharmaceuticals, skincare products, pesticides, and endocrine disruptors. Furthermore, these pollutants contain aromatic rings and are structurally stable, making them difficult to degrade in the natural environment. Consequently, they can persist in water bodies for long periods of time, gradually accumulating through the food chain and ultimately impacting human health. Therefore, the development of effective technologies and methods is currently of paramount importance. Summary of the Invention

[0003] (1) Purpose of the invention

[0004] The primary purpose of the present invention is to provide a preparation method and application of an alumina-loaded iron-aluminum co-doped graphene-like catalyst for synergistic microbial water purification.

[0005] Another object of the present invention is to provide a supported catalyst prepared by the above method, wherein the catalyst is a nitrogen-doped graphene-like iron-aluminum co-complex supported on alumina beads, and the catalyst exhibits good catalytic degradation activity and stability for organic pollutants.

[0006] Another object of the present invention is to provide the use of the above-mentioned immobilized catalyst in the rapid degradation of refractory organic pollutants in water in collaboration with microorganisms.

[0007] (2) Technical solution

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

[0009] A method for preparing an alumina-supported iron-aluminum co-doped graphene-like catalyst comprises the following steps:

[0010] (1) Disperse the biomass in deionized water and stir for 30 min to obtain suspension A;

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

[0012] (3) Adding the nitrogen source to the suspension A and dissolving it completely to form an impregnation solution C;

[0013] (4) Pour the impregnation solution C into a beaker containing alumina pellets, let it stand at 80°C, and dry it at 80°C to obtain dry pellets;

[0014] (5) The dried pellets are placed in a tube furnace and calcined under inert gas. After cooling to room temperature, they are repeatedly washed with water and dried to obtain a solid-supported catalyst.

[0015] Preferably, in step (1), the biomass includes one or a combination of two or more of silkworm excrement, corn cobs, garlic straw, cyclodextrin and chitosan; the amount of the biomass is 0 to 100 g per 1 L of water.

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

[0017] Preferably, in step (3), the nitrogen source includes urea, dicyandiamide, melamine and triethylenetetramine, and the mass of the nitrogen source used in each 1L of water is 0-100g.

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

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

[0020] An alumina-supported iron-aluminum co-doped graphene-like catalyst prepared by the method according to any one of claims 1 to 6.

[0021] Preferably, the alumina-supported iron-aluminum co-doped graphene-like catalyst is used in the degradation of organic pollutants in water.

[0022] An application of an alumina-supported iron-aluminum co-doped graphene-like catalyst in degrading organic pollutants in water comprises the following steps:

[0023] Dispersing the alumina-supported iron-aluminum co-doped graphene-like catalyst according to claim 7 uniformly in water containing organic pollutants;

[0024] The organic pollutants include at least one of tetracycline (TC), bisphenol A (BPA) and ciprofloxacin (CIP).

[0025] A set of solidification bed reactors for realizing the application described in any one of claims 1 to 6, comprising a solidification bed, a peristaltic pump and a plurality of liquid inlet pipes; a water inlet is provided at the bottom of the solidification bed, and a water outlet and a packing port are provided at the upper end; the pollutant liquid inlet pipe enters the solidification bed through the peristaltic pump to react with the catalyst, and after the pollutants are degraded, the solution flows out from the outlet water, completing the treatment.

[0026] (3) Beneficial effects

[0027] (1) The catalyst of the present invention can rapidly degrade refractory organic pollutants in water within 30 minutes in collaboration with microorganisms.

[0028] (2) The catalyst of the present invention has good stability in the process of removing organic pollutants and almost no metal ions are released.

[0029] (3) The catalyst of the present invention is a solid-supported industrial application catalyst, which is easy to separate from water and easy to recycle.

[0030] (4) The catalyst of the present invention has cheap raw materials, low cost, convenient synthesis and simple process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a photo of the catalyst prepared in Example.

[0032] Figure 2 Schematic diagram of the structure of the solidification bed reactor; wherein, 1-pollutant inlet pipe, 2-peristaltic pump, 3-solidification bed, 4-water outlet, 5-catalyst.

[0033] Figure 3 This is a curve diagram of the degradation effect of catalyst on CIP.

[0034] Figure 4 This is a curve diagram of the degradation effect of catalyst on TC.

[0035] Figure 5 This is a curve diagram of the degradation effect of the catalyst on BPA. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Example 1

[0038] As an embodiment of the present invention, a FeAl-NC-Al2O3 water purification catalyst is used as a fixed bed filler in the degradation of organic pollutants in water, and the method includes the following steps:

[0039] like Figure 2 As shown, a fixed bed reactor is built to treat organic pollutants in water. The operating conditions of the fixed bed reactor are as follows: the organic pollutants are transported to the fixed bed 3 through the peristaltic pump 2, the flow rate of the organic pollutant (BPA) is 1.8 mL / min, the residence time is 30 min, and the solution is neutral. Figure 3 As can be seen in the figure, the CIP removal rate reached 100% during the first 46 days of operation. However, as the operation progressed, the CIP removal rate slowly declined and gradually stabilized, ultimately remaining above 54.2%. This is likely due to the initial adsorption of CIP by the catalyst. After a period of operation, microorganisms accumulated on the catalyst surface and gradually adapted to the CIP, at which point the microorganisms began to take effect.

[0040] Example 2

[0041] As an embodiment of the present invention, a FeAl-NC-Al2O3 water purification catalyst is used as a fixed bed filler in the degradation of organic pollutants in water, and the method includes the following steps:

[0042] like Figure 2 As shown, 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 through the peristaltic pump 2, the flow rate of organic pollutants (TC) is 1.8mL / min, the residence time is 30min, and the solution is neutral. Figure 4 As can be seen in the figure, the FeAl-NC-Al2O3 biofiltration reactor demonstrated sustained and efficient degradation of TC throughout its 106-day operation, maintaining a 100% removal rate. Combined with the previous results for CIP removal, TC removal in the initial stages of operation primarily relied on adsorption. However, as the reactor continued to operate, microorganisms accumulated on the catalyst surface, at which point they began to take effect.

[0043] Example 3

[0044] As an embodiment of the present invention, a FeAl-NC-Al2O3 water purification catalyst is used as a fixed bed filler in the degradation of organic pollutants in water, and the method includes the following steps:

[0045] like Figure 2As shown, 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 through the peristaltic pump 2, the flow rate of organic pollutants (CIP) is 1.8mL / min, the residence time is 30min, and the solution is neutral. Figure 5 It can be seen that the degradation of BPA gradually improves with the passage of operating days and finally reaches 100%.

[0046] The matrix material of the present invention is cheap, low-cost, easy to synthesize, and has a simple process. In addition, no solid foreign matter such as iron mud is generated during the reaction, and no foreign matter removal device is required. The small spherical particles are more suitable for actual water treatment applications than powder catalysts developed in the laboratory, and are easy to separate from water and to recycle.

[0047] The above results fully demonstrate that the new alumina-loaded iron-aluminum co-doped graphene-like water purification catalyst can be applied to the treatment of actual organically polluted water bodies.

[0048] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and substance of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications and substitutions shall be within the scope of the present invention. Any changes or substitutions that can be readily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall be within the scope of protection of the present invention.

Claims

1. A method for preparing an alumina-supported iron-aluminum co-doped graphene-like catalyst, characterized in that: The steps include: (1) Disperse the biomass in deionized water and stir for 30 min to obtain suspension A; (2) adding metallic iron salt and aluminum salt to suspension A, stirring uniformly and adjusting the pH of the solution to obtain impregnation solution B; (3) Adding the nitrogen source to the suspension A and dissolving it completely to form an impregnation solution C; (4) Pour the impregnation solution C into a beaker containing alumina pellets, let it stand at 80°C, and dry it at 80°C to obtain dry pellets; (5) The dried pellets are placed in a tube furnace and calcined under inert gas. After cooling to room temperature, they are repeatedly washed with water and dried to obtain a solid-supported catalyst.

2. The method for preparing an alumina-supported iron-aluminum co-doped graphene-like catalyst according to claim 1, wherein: In step (1), the biomass includes one or a combination of two or more of silkworm excrement, corn cobs, garlic straw, cyclodextrin and chitosan; the amount of the biomass is 0 to 100 g per 1 L of water.

3. The method for preparing an alumina-supported iron-aluminum co-doped graphene-like catalyst according to claim 1, wherein: In step (2), the iron salt includes ferric chloride, ferric nitrate, ferric sulfate, ferric acetate, etc., and the amount of iron salt used in each 1L of water is 0-30mM of iron ion; the aluminum salt includes aluminum chloride, aluminum nitrate, aluminum sulfate, etc., and the ratio of iron to aluminum is (1-5):

1.

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

5. The method for preparing an alumina-supported iron-aluminum co-doped graphene-like catalyst according to claim 1, wherein: In step (4), the amount of alumina balls used per 1L of water is 300-900g.

6. The method for preparing an alumina-supported iron-aluminum co-doped graphene-like catalyst according to claim 1, wherein: In step (5), the heating rate of the tubular furnace is 5°C / min, the temperature is maintained at 500-900°C, and the residence time is 2-5 hours.

7. An alumina-supported iron-aluminum co-doped graphene-like catalyst prepared by the method according to any one of claims 1 to 6.

8. Use of the alumina-supported iron-aluminum co-doped graphene-like catalyst as claimed in claim 7 in the degradation of organic pollutants in water.

9. Use of an alumina-supported iron-aluminum co-doped graphene-like catalyst in the degradation of organic pollutants in water according to claim 8, characterized in that: The following steps are involved: Dispersing the alumina-supported iron-aluminum co-doped graphene-like catalyst according to claim 7 uniformly 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 realizing the application according to any one of claims 1 to 6, characterized in that: It includes a solidification bed, a peristaltic pump and several liquid inlet pipes; the bottom of the solidification bed is provided with a water inlet, and the upper end is provided with a water outlet and a filling port; the pollutant inlet pipe enters the solidification bed through the peristaltic pump to react with the catalyst. After the pollutants are degraded, the solution flows out from the outlet water, completing the treatment.

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