Aluminum-iron-carbon micro-electrolysis filler, preparation method and application thereof

Abstract

This invention provides a method for preparing aluminum-iron-carbon micro-electrolysis filler and its application, belonging to the field of wastewater treatment technology. The preparation steps of the aluminum-iron-carbon micro-electrolysis filler are as follows: first, aluminum powder, iron powder, carbon powder, binder, and pore-forming agent are mixed evenly; then water is added to granulate the mixture to prepare a green blank; the green blank is dried in an oven; and then calcined at high temperature under an inert atmosphere to obtain the aluminum-iron-carbon micro-electrolysis filler. This invention utilizes the potential difference between aluminum, iron, and carbon materials to construct a multi-element micro-galvanic cell system, accelerating electron transfer and enhancing reaction kinetics through multi-level potential gradients. The filler has high mechanical strength, well-developed pores, and resistance to caking and passivation. It can maintain micro-electrolysis activity in a wide pH range (2~12) and high-salinity wastewater (salinity 0~70 g / L), effectively removing various organic and inorganic pollutants. Furthermore, the preparation process is simple, cost-controllable, and suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to an aluminum-iron-carbon micro-electrolysis packing material, its preparation method, and its application. Background Technology

[0002] Driven by industrialization and urbanization, industrial production processes generate large quantities of high-salinity wastewater with extremely low biodegradability, which strongly inhibits biological activity, making traditional biological treatment processes difficult to apply directly. Micro-electrolysis technology, due to its low cost, ease of operation, and good environmental compatibility, has become an important pretreatment method for recalcitrant wastewater. This technology relies on the galvanic cell effect formed by metals and carbon materials, primarily through oxidation-reduction, supplemented by electrodeposition, adsorption, and flocculation, to effectively break down the structure of pollutants and improve the biodegradability of wastewater.

[0003] Although iron-carbon micro-electrolysis packing has been applied in the treatment of difficult-to-biochemical wastewater in chemical, pharmaceutical, and electroplating industries, it still has many problems: (1) Iron-carbon micro-electrolysis can only maintain high reactivity under acidic conditions (pH 2-4), and the treatment effect on neutral and alkaline wastewater is significantly reduced. It requires a large amount of acid to adjust the pH, which increases the cost of acid and alkali consumption; (2) The reducing ability of iron materials is relatively weak, the activity decreases too quickly, the electron utilization rate is low, and the long-term operation reliability is insufficient; (3) The packing is prone to caking and passivation, which generates a large amount of iron sludge that clogs the reactor. It needs to be replaced frequently, which increases the operating cost.

[0004] In recent years, aluminum-carbon microelectrolysis systems have gradually attracted the attention of researchers. Aluminum-carbon microelectrolysis overcomes the dependence on acidic conditions inherent in traditional iron-carbon microelectrolysis, allowing reactions to occur in both acidic and alkaline environments, thus reducing acid and alkali consumption costs. However, aluminum-carbon microelectrolysis fillers suffer from problems such as poor mechanical strength and short service life. For example, Huang Mukai et al., in their paper "An Aluminum-Carbon Microelectrolysis Filler and Its Preparation Method and Application" (CN120247174A), used cement as a binder to avoid high-temperature sintering in the filler preparation. However, during long-term immersion and reaction in wastewater, the cement structure may face the risk of pulverization, cracking, or dissolution. Meanwhile, existing aluminum-iron-carbon microelectrolysis fillers and their preparation methods still have room for improvement. For example, Huang Weinong et al., in their "A Preparation Method of Aluminum-Iron-Carbon Micro-Electrolysis Filler" (CN106186209A), used iron concentrate and coal coke powder as raw materials. They first calcined these to obtain high-carbon iron, then pulverized it and mixed it with molten aluminum ingots. After cooling and solidification, the mixture was cut into shapes. While this method achieved the combination of aluminum, iron, and carbon, the process was relatively complex and lacked effective control over the microporous structure of the filler. Therefore, developing a novel aluminum-iron-carbon micro-electrolysis filler with a simple preparation method, capable of efficient and stable operation over a wide pH range, and possessing excellent mechanical strength, anti-caking, and anti-passivation properties, is of significant practical importance. Summary of the Invention

[0005] This invention addresses the shortcomings of existing iron-carbon and aluminum-carbon microelectrolysis fillers by providing a method for preparing and applying an aluminum-iron-carbon microelectrolysis filler that can operate efficiently and stably over a wide pH range, while also possessing excellent mechanical strength, anti-caking, and anti-passivation properties. The technical solution of this invention is as follows:

[0006] One objective of this invention is to provide a method for preparing aluminum-iron-carbon micro-electrolysis fillers, comprising the following steps:

[0007] First, aluminum powder, iron powder, carbon powder, binder and pore-forming agent are mixed evenly; then water is added to granulate and prepare it into a green blank; after the green blank is dried in an oven, it is then calcined at high temperature in an inert atmosphere using a tube furnace to obtain aluminum-iron-carbon micro-electrolysis filler.

[0008] The preparation method described in the above technical solution specifically includes the following steps:

[0009] (1) Material mixing: Mix iron powder, aluminum powder, carbon powder, binder and pore-forming agent evenly according to the following weight percentages: 5~15% iron powder, 35~60% aluminum powder, 10~50% carbon powder, 5~30% binder, 0.5~5% pore-forming agent, and the sum of the weight percentages of each component is 100%;

[0010] (2) Molding: Add an appropriate amount of deionized water to the mixture obtained in step (1), stir to make a paste slurry, and then extrude it through a granulator to obtain the green material;

[0011] (3) Drying: Place the green blank obtained in step (2) in an oven at 40~100℃ and dry for 2~12 h to reduce the moisture content to below 5% to obtain the dried blank;

[0012] (4) High-temperature calcination: The dried blank obtained in step (3) is placed in a tube furnace and heated to 300-800℃ at a heating rate of 5-15℃ / min under inert gas protection. The blank is calcined for 0.5-3 h to sinter and solidify the components and form a micro-electrolysis galvanic cell structure.

[0013] In the above technical solution, in step (1), the iron powder is selected from one or more of reduced iron powder, sponge iron powder or iron ore powder, with a particle size of 60-800 mesh; the aluminum powder is selected from one or more of reduced aluminum powder, aluminum shavings or waste aluminum, with a particle size of 60-600 mesh; the carbon powder is selected from one or more of activated carbon powder, coal coke powder or biochar powder, with a particle size of 100-300 mesh.

[0014] In the above technical solution, in step (1), the adhesive is one or more of a mixture of phenolic resin and sodium carboxymethyl cellulose (mass ratio of 1: (0.2~1)), sodium silicate, or sodium tetraborate; the pore-forming agent is one or more of urea, melamine, ammonium sulfate, glucose, ammonium carbonate, or sodium bicarbonate.

[0015] In the above technical solution, in step (4), the inert gas is one or more of nitrogen, helium or argon.

[0016] In the above technical solution, more preferably, the high-temperature calcination process in step (4) is as follows: first, the temperature is raised from room temperature to 300℃ at a heating rate of 5~15℃ / min, and held for 10~30 min to facilitate the decomposition of the pore-forming agent to release gas and form primary pores; then, the temperature is raised to 400~800℃ at a heating rate of 10℃ / min, and held for sintering for 0.5~3 h.

[0017] The second objective of this invention is to provide an aluminum-iron-carbon micro-electrolysis filler prepared by the above-mentioned preparation method. The aluminum-iron-carbon micro-electrolysis filler has aluminum as the core active component and iron as the catalyst. It is spherical, elliptical or cylindrical in shape, with a porosity of 40-70% and a particle size of 3-20 mm.

[0018] A third objective of this invention is to provide an application of the aforementioned aluminum-iron-carbon micro-electrolysis packing material in removing pollutants from recalcitrant high-salt wastewater. The products of this invention can effectively remove pollutants through adsorption, reduction, oxidation, and flocculation. Furthermore, the products of this invention are recyclable.

[0019] In the above technical solution, the application method involves using a sequencing batch reactor or a continuous flow reactor with the aluminum-iron-carbon micro-electrolysis packing material. The dosage of the aluminum-iron-carbon micro-electrolysis packing material is 5~500 g / L, the reaction time is 3~26 h, the dissolved oxygen concentration is 0.2~50 mg / L, the wastewater pH is 2~12, and the salt ion concentration (Cl) is [not specified]. - SO4 2- CO3 2- NO3 - (etc.) The concentration is 0~70 g / L.

[0020] The principle of this invention is as follows:

[0021] This invention constructs a multi-element micro-galvanic cell system based on the potential difference between iron, aluminum, and carbon. Its mechanism of action exhibits a dual-mode complementary advantage depending on the pH conditions of the wastewater. In an acidic environment, aluminum and iron simultaneously act as anodes, releasing electrons to reduce pollutants and generating Al. 3+ and Fe 2+ / Fe 3+Further hydrolysis generates hydroxides with strong flocculation effects, such as Al(OH)3, Fe(OH)2, and Fe(OH)3, which achieve efficient removal of suspended solids and colloids through adsorption bridging and net sweeping. Simultaneously, the multi-level potential gradient formed between Al, Fe, and C accelerates electron transfer, enhances micro-electrolysis reaction kinetics, and improves electron utilization efficiency. Under neutral and alkaline conditions, aluminum acts as the anode, while iron and carbon together form a dual-cathode system. This expands the cathode reaction area and reduces local current density, thus slowing the passivation process. At the structural level, binders and high-temperature sintering synergistically achieve tight bonding of all components, giving the packing excellent mechanical strength and structural stability. Pore-forming agents such as sodium bicarbonate thermally decompose to release CO2 and water vapor, constructing abundant interconnected pores within the packing, significantly increasing the specific surface area and the number of active sites, and optimizing the liquid-solid mass transfer pathway. This design enables the packing to maintain efficient, long-lasting, and stable micro-electrolysis treatment performance over a wide pH range.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention provides a method for preparing aluminum-iron-carbon micro-electrolysis filler. The filler can be obtained through conventional mixing-granulation-drying-sintering processes. The equipment is versatile and easy to industrialize and promote. Furthermore, the aluminum powder, iron powder, carbon materials, binder, and pore-forming agent used are industrial-grade raw materials, readily available and suitable for large-scale use, effectively controlling wastewater treatment costs.

[0024] The filler prepared in this invention overcomes the dependence of traditional iron-carbon microelectrolysis on acidic conditions. By introducing aluminum components to construct an Al-Fe-C multi-element micro-galvanic cell system, it achieves efficient electrochemical response over a wide pH range (2-12). The introduction of iron increases the electrode potential difference, accelerates electron transfer, and the synergistic formation of a composite flocculation system by aluminum and iron ions is superior to a single metal system. This system can efficiently remove various organic and inorganic substances from wastewater and is widely applicable to various water remediation scenarios.

[0025] The aluminum-iron-carbon micro-electrolysis filler prepared by this invention can resist passivation by high concentrations of salt ions (0~70 g / L) and has broad practical application potential for the treatment of high-salt wastewater.

[0026] The filler particles prepared by this invention have high mechanical strength and hardness, are not easily broken or pulverized during long-term operation, and have a porosity of over 65%, which allows the active components to be more fully exposed in the wastewater, improves the mass transfer efficiency and reaction rate of the micro-electrolysis reaction, effectively prevents the filler layer from caking and clogging, significantly extends the service life, and reduces the frequency of maintenance and replacement. Attached Figure Description

[0027] Figure 1 This is a photograph of the aluminum-iron-carbon micro-electrolysis filler prepared in Example 1 of the present invention.

[0028] Figure 2 The graph shows the change in the removal rate of p-nitrophenol (PNP) under acidic conditions (pH = 2) with time for the aluminum-iron-carbon micro-electrolysis filler prepared in Example 2 of this invention and for comparative examples 1-3.

[0029] Figure 3 The graph shows the change in PNP removal rate over time under alkaline conditions (pH = 12) for the aluminum-iron-carbon micro-electrolysis filler prepared in Example 2 of this invention and for comparative examples 1-3.

[0030] Figure 4 This is a comparison chart showing the effect of the aluminum-iron-carbon micro-electrolysis packing material prepared in Example 1 of the present invention on treating PNP wastewater under different pH conditions.

[0031] Figure 5 The aluminum-iron-carbon micro-electrolysis filler prepared in Example 1 of this invention is used to treat organic pollutants such as Active Black 5 and Golden Orange. The removal rates of methyl orange and p-chloronitrobenzene change over time.

[0032] Figure 6 This is a graph showing the change in the removal rate of copper ions, an inorganic pollutant, by the aluminum-iron-carbon micro-electrolysis filler prepared in Example 2 of the present invention over time.

[0033] Figure 7 This is a graph showing the change in the removal rate of PNP by activated oxygen treatment using the aluminum-iron-carbon micro-electrolysis filler prepared in Example 1 of the present invention over time.

[0034] Figure 8 This is a graph showing the change in the removal rate of PNP over time when treated with the aluminum-iron-carbon micro-electrolysis filler prepared in Example 1 of the present invention in the presence of high concentrations of coexisting ions.

[0035] Figure 9 The diagram shows the recycling performance of the aluminum-iron-carbon micro-electrolysis packing material prepared in Example 1 of this invention for treating PNP wastewater. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be clearly and completely described below with reference to examples. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0038] Example 1

[0039] Weigh the following raw materials according to the following weight percentages: 10% iron powder (200-300 mesh), 45% aluminum powder (100-200 mesh), 22% coconut shell activated carbon (200 mesh), 15% phenolic resin, 5% sodium carboxymethyl cellulose, and 3% sodium bicarbonate. Mix the weighed raw materials thoroughly to obtain a mixed powder. Add water to the mixed powder and stir until it forms a dough. Place the dough in a granulator to produce spherical green bodies with a particle size of 8 mm. Place the green bodies in an oven and dry at 70℃ for 2 hours. Place the dried green bodies in a tube furnace and, under nitrogen protection, heat to 600℃ at a rate of 10℃ / min, hold for 90 minutes, and then cool to room temperature with the furnace. The resulting aluminum-iron-carbon micro-electrolysis filler is then obtained.

[0040] like Figure 1 As shown, the aluminum-iron-carbon micro-electrolysis filler appears as black, regular spheres with certain mechanical strength and abundant pore structure, with a porosity of 65.4%.

[0041] Example 2

[0042] The difference from Example 1 is that the amount of iron powder is 10%, aluminum powder is 36%, coconut shell activated carbon powder is 36%, phenolic resin is 10%, sodium carboxymethyl cellulose is 5%, and sodium bicarbonate is 3%. The remaining steps are the same as in Example 1.

[0043] Comparative Example 1

[0044] The difference from Example 1 is that aluminum powder and iron powder are not added, and the content of coconut shell activated carbon powder is 82%, phenolic resin is 10%, sodium carboxymethyl cellulose is 5%, and sodium bicarbonate is 3%. The remaining steps are the same as in Example 1.

[0045] Comparative Example 2

[0046] The difference from Example 1 is that aluminum powder is not added, iron powder is 10%, coconut shell activated carbon powder is 72%, phenolic resin is 10%, sodium carboxymethyl cellulose is 5%, and sodium bicarbonate is 3%. The remaining steps are the same as in Example 1.

[0047] Comparative Example 3

[0048] The difference from Example 1 is that: no iron powder is added, aluminum powder is 36%, coconut shell activated carbon powder is 46%, phenolic resin is 10%, sodium carboxymethyl cellulose is 5%, and sodium bicarbonate is 3%. The remaining steps are the same as in Example 1.

[0049] Wastewater treatment performance test

[0050] (a) Test on the removal efficiency of p-nitrophenol (PNP)

[0051] 250 mL of 50 mg / L p-nitrophenol (PNP) solution was prepared in multiple serum bottles. The pH of one group of solutions was adjusted to 2, and the pH of the second group of solutions was adjusted to 12. Then, the aluminum-iron-carbon microelectrolysis packing material prepared in Example 2 (6 g / L) and the carbon, iron-carbon, and aluminum-carbon microelectrolysis packing materials prepared in Comparative Examples 1-3 were added to the serum bottles. The amount of packing material added in Comparative Examples 1-3 was the same as the mass of each component in the aluminum-iron-carbon microelectrolysis packing material in Example 2. The serum bottles were sealed and placed in a constant temperature water bath shaker set at 25°C and 200 rpm. Samples were taken at the set time points and filtered through a 0.45 μm filter membrane. The remaining PNP concentration was detected using a UV spectrophotometer. The results are as follows. Figure 2 and Figure 3 As shown.

[0052] like Figure 2 and Figure 3 As shown, the aluminum-iron-carbon micro-electrolysis filler prepared in Example 2 can completely remove 50 mg / L of PNP within 8 h under both acidic and alkaline conditions, and the removal effect is better than that of carbon, iron-carbon and aluminum-carbon micro-electrolysis fillers, proving that there is a synergistic effect between aluminum, iron and carbon, which enhances the removal of pollutants.

[0053] (II) Pollutant removal capacity test at different pH values

[0054] 250 mL of 50 mg / L PNP solution was prepared in multiple serum bottles, and the initial pH of the solution was adjusted to 2, 4, 5.57, 8, 10, and 12. Then, the aluminum-iron-carbon microelectrolysis packing material prepared in Example 1 (6 g / L) was added to the serum bottles. The serum bottles were then sealed and placed in a constant-temperature water bath shaker at 25°C and 200 rpm. Samples were taken at set time points, filtered through a 0.45 μm filter membrane, and the remaining PNP concentration was detected using a UV spectrophotometer. The results are shown below. Figure 4 As shown.

[0055] Depend on Figure 4 It can be seen that the aluminum-iron-carbon micro-electrolysis filler prepared in Example 1 can efficiently remove PNP in a wide pH range (2~12), with a removal rate of over 93%. Moreover, the removal rate is even faster under strong acid and strong alkaline conditions.

[0056] (III) Organic pollutant removal capacity test

[0057] 250 mL of Active Black 5 and Golden Orange at a concentration of 50 mg / L were prepared in multiple serum bottles. The initial pH of the solution was adjusted to 12 using methyl orange and p-chloronitrobenzene solutions. Then, the aluminum-iron-carbon microelectrolysis packing material prepared in Example 1 (6 g / L) was added to the serum bottle. The serum bottle was then sealed and placed in a constant temperature water bath shaker at 25°C and 200 rpm. Samples were taken at the set time points, filtered through a 0.45 μm filter membrane, and the concentration of residual contaminants was detected using a UV spectrophotometer.

[0058] like Figure 5 As shown, the aluminum-iron-carbon micro-electrolysis filler prepared in Example 1 can remove more than 80% of organic pollutants such as Active Black 5, Golden Orange II, Methyl Orange and p-chloronitrobenzene within 10 h.

[0059] (iv) Inorganic pollutant removal capacity test

[0060] Prepare 100 mL of a 100 mg / L copper ion solution, adjust the initial pH of the solution to 3, and then add the aluminum-iron-carbon microelectrolysis packing material prepared in Example 2 (addition amount: 6 g / L) to the serum bottle. Seal the serum bottle and place it in a constant temperature water bath shaker set to 25°C and 200 rpm. Samples were taken at the set time points, filtered through a 0.45 μm filter membrane, and the concentration of residual contaminants was detected using a UV spectrophotometer.

[0061] like Figure 6 As shown, the aluminum-iron-carbon micro-electrolysis packing material prepared in Example 2 can completely remove 100 mg / L of copper ions within 6 h, indicating that the packing material can also efficiently remove inorganic pollutants.

[0062] (v) Oxygen Activation Capacity Test

[0063] Prepare 250 mL of 50 mg / L PNP solution in multiple serum bottles, adjust the initial pH of the solution to 12, and then add the aluminum-iron-carbon microelectrolysis packing material prepared in Example 1 (6 g / L). Place the serum bottles in a magnetic stirrer at 200 rpm, and adjust the dissolved oxygen concentration by adjusting the ratio of nitrogen, air, and oxygen introduced. Samples were taken at set time points, filtered through a 0.45 μm filter membrane, and the concentration of residual contaminants was detected using a UV spectrophotometer.

[0064] like Figure 7 As shown, the aluminum-iron-carbon micro-electrolysis packing material prepared in Example 1 can efficiently activate molecular oxygen. Under air circulation conditions (dissolved oxygen concentration of 6.38 mg / L), the removal rate of PNP reached 95.5% and the removal rate of COD reached 70.7%.

[0065] (vi) Test on resistance to passivation by high concentration of coexisting ions

[0066] Prepare 250 mL of 50 mg / L PNP solution in multiple serum bottles. Then, add 500 mM sodium chloride, sodium sulfate, sodium carbonate, and sodium nitrate to the serum bottles respectively, adjusting the pH of the solution to 12. Next, add the aluminum-iron-carbon microelectrolysis packing material prepared in Example 1 (6 g / L). Seal the serum bottles and place them in a constant temperature water bath shaker set to 25°C and 200 rpm. Samples were taken at set time points, filtered through a 0.45 μm filter membrane, and the concentration of remaining contaminants was detected using a UV spectrophotometer.

[0067] like Figure 8 As shown, the removal of PNP by the aluminum-iron-carbon micro-electrolysis packing material prepared in Example 1 was not significantly inhibited in the presence of high concentrations of salt ions (500 mM is equivalent to a γ-salt concentration of 29~71 g / L). This indicates that the packing material can inhibit the passivation of high-salt wastewater, greatly expanding the practical application scenarios of this study.

[0068] (vii) Recycling Capacity Test

[0069] Prepare 250 mL of 50 mg / L PNP solution in multiple serum bottles. Adjust the pH of one group of solutions to 2 and the pH of the second group of solutions to 12. Then, add the aluminum-iron-carbon microelectrolysis packing material prepared in Example 1 (6 g / L) to the serum bottles. After sealing the serum bottles, place them in a constant temperature water bath shaker at 25°C and 200 rpm. After reacting for 10 h, immediately filter the packing material and reuse it in the next round of use.

[0070] like Figure 7 As shown, the aluminum-iron-carbon micro-electrolysis packing material prepared in Example 1 can achieve multiple cycles under both acidic and alkaline conditions. At pH = 12, the PNP removal rate is 80.6% after 10 cycles, and 43.5% of PNP can be removed after 18 cycles. At pH = 2, 85.7% of PNP can be removed after 18 cycles. Furthermore, the packing material did not break during the cycling process, demonstrating its high mechanical strength, which meets the requirements for practical engineering applications.

[0071] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing and applying an aluminum-iron-carbon micro-electrolysis filler, characterized in that, The preparation method of the aluminum-iron-carbon micro-electrolysis filler includes the following steps: (1) Material mixing: Mix iron powder, aluminum powder, carbon powder, binder and pore-forming agent evenly according to the following weight percentages: 5~15% iron powder, 35~60% aluminum powder, 10~50% carbon powder, 5~30% binder, 0.5~5% pore-forming agent, and the sum of the weight percentages of each component is 100%; (2) Molding: Add an appropriate amount of deionized water to the mixture obtained in step (1), stir to make a paste slurry, and then extrude it through a granulator to obtain the green material; (3) Drying: Place the green blank obtained in step (2) in an oven at 40~100℃ and dry for 2~12 h to reduce the moisture content to below 5% to obtain the dried blank; (4) High-temperature calcination: The dried blank obtained in step (3) is placed in a tube furnace and heated to 300-800°C at a heating rate of 5-15°C / min under inert gas protection. The blank is calcined for 0.5-3 h to sinter and solidify the components and form a micro-electrolysis galvanic cell structure. Application of the aluminum-iron-carbon micro-electrolysis packing material: The aluminum-iron-carbon micro-electrolysis packing material is added to the difficult-to-degrade high-salt wastewater and micro-electrolysis is carried out through a sequencing batch reactor or a continuous flow reactor.

2. The preparation method according to claim 1, characterized in that, The iron powder is selected from one or more of reduced iron powder, sponge iron powder, or iron ore powder, with a particle size of 60-800 mesh; the aluminum powder is selected from one or more of reduced aluminum powder, aluminum shavings, or waste aluminum, with a particle size of 60-600 mesh; the carbon powder is selected from one or more of activated carbon powder, coal coke powder, or biochar powder, with a particle size of 100-300 mesh.

3. The preparation method according to claim 1, characterized in that, The adhesive is one or more of a mixture of phenolic resin and sodium carboxymethyl cellulose, sodium silicate, or sodium tetraborate; the pore-forming agent is one or more of urea, melamine, ammonium sulfate, glucose, ammonium carbonate, or sodium bicarbonate.

4. The preparation method according to claim 1, characterized in that, In step (4), the inert gas used in the high-temperature calcination process is one or more of nitrogen, helium, or argon.

5. An aluminum-iron-carbon micro-electrolysis filler prepared by the preparation method according to any one of claims 1-4, characterized in that, The aluminum-iron-carbon micro-electrolysis filler uses aluminum as the core active component and iron as the catalyst. It is spherical, elliptical or cylindrical in shape, with a porosity of 40-70% and a particle size of 2-20 mm.

6. The application of the aluminum-iron-carbon micro-electrolysis packing material according to claim 1 in removing recalcitrant high-salt wastewater, characterized in that, The dosage of the aluminum-iron-carbon micro-electrolysis packing is 5~500 g / L, the reaction time is 3~26 h, the dissolved oxygen concentration is 0.2~50 mg / L, the wastewater pH is 2~12, and the salt ion concentration (Cl) is [not specified]. - SO4 2- CO3 2- NO3 - The content of (etc.) is 0~70 g / L.

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