ORP (Oxidation Reduction Potential) regulation slow-release material as well as preparation method and

Abstract

The preparation method comprises the following steps: crushing biomass, adding the crushed biomass into deoxygenated purified water, adding polyvinylpyrrolidone, adding ferric salt, and stirring; centrifuging and drying to obtain an iron-carbon core-shell precursor; calcining the iron-carbon core-shell precursor in an N2 atmosphere to obtain an iron-carbon core-shell material; and dissolving cerous nitrate in ammonia water, adding the iron-carbon core-shell material, stirring, carrying out centrifugal separation, drying, and finally roasting to obtain the ORP regulation and control slow-release material. According to the prepared ORP regulation and control slow-release material, a CeO2 layer can be effectively used as a barrier to isolate corrosion of chloride ions in a water body to a Fe0 (at) C core, and then the micro-electrolysis speed of Fe0 (at) C is precisely regulated and controlled. The mechanism ensures that the oxidation-reduction potential (ORP) in the anaerobic degradation system is kept stable for a long time, an optimized living environment is constructed for the microbial community, and finally the anaerobic degradation system is promoted to form good biodegradation efficiency and a stable microbial community structure.

Description

Technical Field

[0001] The present invention relates to the field of water pollutant treatment, and particularly relates to an ORP regulation and slow-release material, a preparation method thereof, and an application thereof. Background Art

[0002] The oxidation-reduction potential (ORP) is one of the important parameters in the anaerobic degradation system, and is an index for measuring the oxidizing and reducing properties in a solution, which reflects the balance between oxidants and reductants.

[0003] Under anaerobic conditions, microorganisms usually use other compounds instead of oxygen as the terminal electron acceptor for energy metabolism. The change of ORP can regulate the activity of the microbial metabolic pathway and the production rate of products. During the fermentation process carried out under anaerobic conditions, it is sometimes necessary to prevent the occurrence of excessive reduction reactions and oxidation reactions. Maintaining an appropriate ORP can reduce the presence of oxidants, thereby slowing down or preventing unexpected redox reactions and protecting the degradation performance of pollutants and methane production rate. However, too high or too low ORP will cause the anaerobic degradation system to be inhibited. When the ORP is too high, VFAs may accumulate in the system, resulting in a decrease in pH, thereby inhibiting the activity and growth of microorganisms, which will lead to a reduction in the wastewater treatment efficiency and an increase in the operating cost of the system; when the ORP is too low, on the one hand, the pH of the system will slightly increase, and on the other hand, too low pH will inhibit the hydrolysis and acidification of anaerobic microorganisms, and even the methanogenesis stage, which significantly reduces the performance of the anaerobic digestion system. In addition, the oxidation substances generated during the anaerobic digestion process will increase the ORP and accelerate the corrosion of the material, thus making the ORP regulation unstable.

[0004] Only a long-term stable ORP can keep the anaerobic degradation system in an excellent state. Therefore, controlling the ORP at an appropriate potential is the key measure to ensure the long-term stable operation of the anaerobic degradation system.

[0005] The material of the present invention ensures that the ORP of the wastewater in anaerobic degradation is maintained within a suitable range for a long time by preparing an ORP regulation and slow-release material. Secondly, this material can not only act as the nucleus for the growth and reproduction of microorganisms, providing a good environment for the growth and reproduction of anaerobic microorganisms, and thus maintaining the long-term health and stability of the anaerobic degradation system. Thirdly, this material can help oxidize pollutants, making them change from macromolecular substances into medium and small molecular substances that are easy to be degraded and utilized by anaerobic microorganisms, thereby further promoting the performance of the anaerobic degradation system. In summary, the material of the present invention makes the ORP within an appropriate range by preparing an ORP regulation and slow-release material, enables the anaerobic degradation system to have long-term ORP stability and pollutant degradation performance, and enables the anaerobic degradation system to have a good biodegradation effect. Summary of the Invention

[0006] Technical problems to be solved: In view of the above technical problems, the present invention provides an ORP regulation and slow-release material, a preparation method thereof, and an application thereof. By preparing an ORP regulation and slow-release material, the long-term stability of the ORP of wastewater in anaerobic degradation is ensured. Secondly, this material can not only serve as the nucleus for the growth and reproduction of microorganisms, providing a good growth and reproduction environment for anaerobic microorganisms, thereby maintaining the long-term health and stability of the anaerobic degradation system. Thirdly, this material can help oxidize pollutants through iron-carbon microelectrolysis, converting them from macromolecular substances into medium and small molecules that are easily degradable and utilizable by anaerobic microorganisms, thereby further promoting the performance of the anaerobic degradation system. Finally, when Cl - corrodes the ORP adjustment material, CeO 2 can shield the corrosiveness of Cl - to the ORP adjustment material, avoiding the too-fast iron-carbon microelectrolysis, so as to ensure the long-term stability of the ORP adjustment ability and a good biodegradation effect.

[0007] Technical solution: A preparation method of an ORP regulation and slow-release material includes the following steps: 1) Preparation of an iron-carbon core-shell precursor: Crush biomass and add it to deoxygenated purified water, then add polyvinylpyrrolidone, and then add iron salt and stir; after centrifugation, dry to obtain the iron-carbon core-shell precursor; the mass concentration of polyvinylpyrrolidone in the reaction system is 0.5% - 1%, and the mass ratio of the iron salt to the biomass is (1 - 20):1; 2) Preparation of the iron-carbon core-shell material: Calcinate the iron-carbon core-shell precursor in an N 2 atmosphere to obtain the iron-carbon core-shell material; 3) Preparation of the Fe 0 @C@CeO 2 slow-release material: Dissolve cerium nitrate in ammonia water, add the iron-carbon core-shell material, the mass ratio of cerium nitrate to the iron-carbon core-shell material is 1:(1 - 10), stir, then centrifuge and separate and dry, and finally calcine to obtain the ORP regulation and slow-release material.

[0008] Preferably, the above-mentioned biomass is tea residue, rice straw residue, coconut shell or wax gourd peel.

[0009] Preferably, the mesh number of the above-mentioned crushed biomass is 500 - 2500 mesh.

[0010] Preferably, the above-mentioned iron salt is ferric sulfate, ferric nitrate or ferric chloride.

[0011] Preferably, the mass ratio of the above-mentioned iron salt to the biomass is (1 - 10):1; the centrifugation time is 5 - 20 min, and the vacuum drying time is 8 h - 24 h.

[0012] Preferably, in the above step 2), the calcination temperature is 400 - 900 °C, and the reaction time is 1 - 8 h.

[0013] Preferably, in the above step 3), the roasting temperature is 600-1000 °C, and the reaction time is 1-8 h.

[0014] The ORP-regulating slow-release material prepared by the above method.

[0015] Application of the above ORP-regulating slow-release material in an electrochemical catalytic system.

[0016] Beneficial effects: The Fe 0 @C@CeO 2 ORP-regulating slow-release material prepared in the present invention can effectively utilize the CeO 2 layer as a barrier to isolate the erosion of chloride ions (Cl - ) in water on the Fe 0 @C core, and then precisely regulate the micro-electrolysis rate of Fe 0 @C. This mechanism ensures that the oxidation-reduction potential (ORP) in the anaerobic degradation system remains stable for a long time, constructs an optimized living environment for the microbial community, and finally promotes the formation of good biodegradation efficiency and stable microbial community structure in the anaerobic degradation system. Description of the drawings

[0017] Figure 1 Changes in ORP of the anaerobic degradation system over two months when the catalysts are Fe 0 @C@CeO 2 , Fe 0 @C, and CeO 2 respectively.

[0018] Figure 2 Degradation efficiency of 2048 mg / L terephthalic acid when the catalysts are Fe 0 @C@CeO 2 , Fe 0 @C, and CeO 2 respectively.

[0019] Figure 3 Degradation efficiency of 2048 mg / L isophthalic acid when the catalysts are Fe 0 @C@CeO 2 , Fe 0 @C, and CeO 2 respectively.

[0020] Figure 4 Degradation efficiency of 3000 mg / L TA acid when the catalysts are Fe 0 @C@CeO 2 , Fe 0 @C, and CeO 2 respectively.

[0021] Figure 5 When the catalyst is Fe 0 @C@CeO 2 、Fe 0 @C、CeO 2 The cyclic voltammetry curves are shown as follows

[0022] Figure 6 When the concentration of terephthalic acid is 2048 mg / L, and the catalysts are Fe 0 @C@CeO 2 、Fe 0 @C、CeO 2 The long-term degradation efficiency curve of terephthalic acid after 61 days of continuous reaction

[0023] Figure 7 The bar chart of the degradation efficiency of terephthalic acid among ten examples when the pollutant is terephthalic acid with a concentration of 2048 mg / L

[0024] Figure 8 The bar chart of the degradation efficiency of isophthalic acid among ten examples when the pollutant is isophthalic acid with a concentration of 2048 mg / L

[0025] Figure 9 When different biomasses are used as carbon sources, the ORP regulation performance of Fe 0 @C@CeO 2 prepared with different carbon sources Specific embodiments

[0026] Cyclic voltammetry curve test: Using a Pt sheet electrode as the counter electrode, Ag / AgCl as the reference electrode, and the cathode as the working electrode for CV analysis. A cyclic voltammetry (CV) test was performed using an electrochemical workstation. The voltage scan range of CV was -0.8 to -0.8 V, and the scan rate was 10 mV / s

[0027] Terephthalic acid, isophthalic acid, and TA acid test: Terephthalic acid, isophthalic acid, and TA acid were detected by high-performance liquid chromatography (HPLC, Agilent, U.S.). Specifically, the column oven was operated at 40 °C, and the degradation efficiency was calculated according to Equation (1):

[0028] Degradation rate = (1 - C1 / C0) × 100% Equation (1)

[0029] C0: influent concentration (mg / L); C1: effluent concentration (mg / L)

[0030] Example 1

[0031] In this example, the specific preparation method of the ORP regulation and slow-release material is as follows

[0032] (1) Grind and pulverize 33 g of tea leaf residues with a wall breaker, sieve them through a 500 - mesh sieve, then place them in anaerobic purified water, and add 0.15 g of polyvinylpyrrolidone (PVP) and 11 g of FeCl 3 Stir. Centrifuge for 10 min and dry in a vacuum drying oven for 8 h to obtain the iron - carbon core - shell precursor Fe 0 @C.

[0033] (2) Place the Fe 0 @C core - shell material precursor obtained in step (1) in a tubular furnace and under an N 2 atmosphere, calcine at 600 °C for 1 h to obtain the iron - carbon core - shell material.

[0034] (3) Dissolve 11 g of cerium nitrate in 500 mL of ammonia water with a concentration of 15%, and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core - shell material prepared in step (2) into it, stir for 2 h, then centrifuge and dry in a vacuum drying oven for 4 h. Finally, place it in a tubular furnace and calcine at 1000 °C for 3 h to obtain Fe 0 @C@CeO 2 ORP - regulating slow - release material.

[0035] Use the prepared Fe 0 @C@CeO 2 ORP - regulating slow - release material to regulate the long - term stability of the ORP of wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system, and construct an excellent microbial community in the anaerobic degradation system.

[0036] Example 2

[0037] In this example, the specific preparation method of the ORP - regulating slow - release material is as follows:

[0038] (1) Grind and pulverize 20 g of rice straw with a wall breaker, sieve them through a 1500 - mesh sieve, then place them in anaerobic purified water, and add 0.05 g of polyvinylpyrrolidone (PVP) and 10 g of FeSO 4 Stir. Centrifuge for 10 min and dry in a vacuum drying oven for 8 h to obtain the iron - carbon core - shell precursor Fe 0 @C.

[0039] (2) Place the Fe 0 @C core - shell material precursor obtained in step (1) in a tubular furnace and under an N 2 atmosphere, calcine at 600 °C for 1 h to obtain the iron - carbon core - shell material.

[0040] (3) Dissolve 11 g of cerium nitrate in 500 mL of ammonia water with a concentration of 15%, and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) into it. After stirring for 2 h, centrifuge and separate, and place it in a vacuum drying oven for drying for 4 h. Finally, place it in a tube furnace and calcine at 1000 °C for 3 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release material.

[0041] Use the prepared Fe 0 @C@CeO 2 ORP regulation and slow-release material to regulate the long-term stability of the ORP of the wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system, and construct an excellent microbial community in the anaerobic degradation system.

[0042] Example 3

[0043] In this example, the specific preparation method of the ORP regulation and slow-release material is as follows:

[0044] (1) Grind and crush 60 g of coconut shell with a wall breaker, sieve it through a 2500 mesh sieve, then place it in anaerobic purified water, and add 0.15 g of polyvinylpyrrolidone (PVP) and 10 g of FeCl 3 Stir. Centrifuge for 5 min and place it in a vacuum drying oven for drying for 8 h to obtain the iron-carbon core-shell precursor Fe 0 @C.

[0045] (2) Place the Fe 0 @C core-shell material precursor prepared in step (1) in a tube furnace and under N 2 atmosphere, calcine at 800 °C for 2 h to obtain the iron-carbon core-shell material.

[0046] (3) Dissolve 20 g of cerium nitrate in 500 mL of ammonia water with a concentration of 15%, and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) into it. After stirring for 2 h, centrifuge and separate, and place it in a vacuum drying oven for drying for 4 h. Finally, place it in a tube furnace and calcine at 1000 °C for 3 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release material.

[0047] Use the prepared Fe 0 @C@CeO 2 ORP regulation and slow-release material to regulate the long-term stability of the ORP of the wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system, and construct an excellent microbial community in the anaerobic degradation system.

[0048] Example 4

[0049] In this example, the specific preparation method of the ORP regulation and slow-release material is as follows:

[0050] (1) Grind and crush 10 g of wax gourd peel with a wall breaker, sieve it through a 500-mesh sieve, then place it in anaerobic purified water, and add 0.05 g of polyvinylpyrrolidone (PVP) and 10 g of FeCl 3 Stir. Centrifuge for 5 min and dry in a vacuum drying oven for 6 h to obtain the iron-carbon core-shell precursor Fe 0 @C.

[0051] (2) Place the Fe 0 @C core-shell material precursor obtained in step (1) in a tubular furnace and under an N 2 atmosphere, calcine at 700 °C for 1 h to obtain the iron-carbon core-shell material.

[0052] (3) Dissolve 20 g of cerium nitrate in 500 mL of ammonia water with a concentration of 15%, and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) thereto, stir for 1 h, then centrifuge and dry in a vacuum drying oven for 4 h. Finally, place it in a tubular furnace and calcine at 1000 °C for 3 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release material.

[0053] Use the prepared Fe 0 @C@CeO 2 ORP regulation and slow-release material to regulate the long-term stability of the ORP of the wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system, and construct an excellent microbial community in the anaerobic degradation system.

[0054] Example 5

[0055] In this example, the specific preparation method of the ORP regulation and slow-release material is as follows:

[0056] (1) Grind and crush 20 g of rice straw with a wall breaker, sieve it through a 2500-mesh sieve, then place it in anaerobic purified water, and add 0.05 g of polyvinylpyrrolidone (PVP) and 20 g of FeSO 4 Stir. Centrifuge for 5 min and dry in a vacuum drying oven for 8 h to obtain the iron-carbon core-shell precursor Fe 0 @C.

[0057] (2) Place the Fe 0 @C core-shell material precursor obtained in step (1) in a tubular furnace and under an N 2Under this atmosphere, calcine at 600 °C for 2 h to obtain the iron-carbon core-shell material.

[0058] (3) Dissolve 20 g of cerium nitrate in 500 mL of 15% ammonia water and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) into it. After stirring for 2 h, perform centrifugal separation and place it in a vacuum drying oven for drying for 3 h. Finally, place it in a tube furnace and calcine at 1000 °C for 2 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release material.

[0059] Use the prepared Fe 0 @C@CeO 2 ORP regulation and slow-release material to regulate the long-term stability of the ORP of the wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system, and construct an excellent microbial community in the anaerobic degradation system.

[0060] Example 6

[0061] In this example, the specific preparation method of the ORP regulation and slow-release material is as follows:

[0062] (1) Grind 60 g of tea residues with a blender, sieve through a 1500 mesh sieve, then place it in anaerobic purified water, and add 0.25 g of polyvinylpyrrolidone (PVP) and 40 g of FeCl 3 Stir. Centrifuge for 10 min and place it in a vacuum drying oven for drying for 8 h to obtain the iron-carbon core-shell precursor Fe 0 @C.

[0063] (2) Place the Fe 0 @C core-shell material precursor prepared in step (1) in a tube furnace and under N 2 atmosphere, calcine at 800 °C for 1 h to obtain the iron-carbon core-shell material.

[0064] (3) Dissolve 40 g of cerium nitrate in 500 mL of 15% ammonia water and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) into it. After stirring for 2 h, perform centrifugal separation and place it in a vacuum drying oven for drying for 4 h. Finally, place it in a tube furnace and calcine at 1000 °C for 1 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release material.

[0065] Use the prepared Fe 0 @C@CeO 2The ORP regulating and slow - release material is used to regulate the long - term stability of the ORP of wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system and construct an excellent microbial community in the anaerobic degradation system.

[0066] Example 7

[0067] In this example, the specific preparation method of the ORP regulating and slow - release material is as follows:

[0068] (1) Grind and crush 30 g of rice straw with a wall - breaker, sieve it through a 2500 - mesh sieve, then place it in anaerobic purified water, and add 0.05 g of polyvinylpyrrolidone (PVP) and 30 g of FeSO 4 Stir. Centrifuge for 10 min and dry in a vacuum drying oven for 12 h to obtain the iron - carbon core - shell precursor Fe 0 @C.

[0069] (2) Place the Fe 0 @C core - shell material precursor obtained in step (1) in a tubular furnace and under an N 2 atmosphere, calcine at 800 °C for 2 h to obtain the iron - carbon core - shell material.

[0070] (3) Dissolve 15 g of cerium nitrate in 500 mL of 15% ammonia water and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core - shell material prepared in step (2) into it, stir for 2 h, then centrifuge and dry in a vacuum drying oven for 2 h. Finally, place it in a tubular furnace and calcine at 1000 °C for 1 h to obtain the Fe 0 @C@CeO 2 ORP regulating and slow - release material.

[0071] The prepared Fe 0 @C@CeO 2 ORP regulating and slow - release material is used to regulate the long - term stability of the ORP of wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system and construct an excellent microbial community in the anaerobic degradation system.

[0072] Example 8

[0073] In this example, the specific preparation method of the ORP regulating and slow - release material is as follows:

[0074] (1) Grind and crush 15 g of coconut shell with a wall - breaker, sieve it through a 1000 - mesh sieve, then place it in anaerobic purified water, and add 0.05 g of polyvinylpyrrolidone (PVP) and 20 g of FeCl 3 Stir. Centrifuge for 10 min and dry in a vacuum drying oven for 12 h to obtain the iron - carbon core - shell precursor Fe 0 @C.

[0075] (2) Place the Fe 0 @C core-shell material precursor in a tube furnace and under N 2 atmosphere, calcine at 800 °C for 2 h to obtain the iron-carbon core-shell material.

[0076] (3) Dissolve 20 g of cerium nitrate in 500 mL of ammonia water with a concentration of 15%, and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) thereto, stir for 2 h, then centrifuge and place in a vacuum drying oven to dry for 3 h. Finally, place it in a tube furnace and calcine at 1000 °C for 2 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release material.

[0077] Use the prepared Fe 0 @C@CeO 2 ORP regulation and slow-release material to regulate the long-term stability of the ORP of the wastewater in the anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system and construct an excellent microbial community in the anaerobic degradation system.

[0078] Example 9

[0079] In this example, the specific preparation method of the ORP regulation and slow-release material is as follows:

[0080] (1) Grind and crush 50 g of tea residues with a wall breaker, sieve through a 2500 mesh sieve, then place it in anaerobic purified water, and add 0.15 g of polyvinylpyrrolidone (PVP) and 10 g of FeSO 4 and stir. Centrifuge for 5 min and place in a vacuum drying oven to dry for 12 h to obtain the iron-carbon core-shell precursor Fe 0 @C.

[0081] (2) Place the Fe 0 @C core-shell material precursor in a tube furnace and under N 2 atmosphere, calcine at 800 °C for 3 h to obtain the iron-carbon core-shell material.

[0082] (3) Dissolve 30 g of cerium nitrate in 500 mL of ammonia water with a concentration of 15%, and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) thereto, stir for 2 h, then centrifuge and place in a vacuum drying oven to dry for 3 h. Finally, place it in a tube furnace and calcine at 1000 °C for 3 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release material.

[0083] The prepared Fe 0 @C@CeO 2 ORP regulation and slow-release materials are used to regulate the long-term stability of the ORP of wastewater in an anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system, and construct an excellent microbial community in the anaerobic degradation system.

[0084] Example 10

[0085] In this example, the specific preparation method of the ORP regulation and slow-release material is as follows:

[0086] (1) Grind 40 g of tea residue with a wall breaker, sieve it through a 2500 mesh sieve, then place it in anaerobic purified water, and add 0.05 g of polyvinylpyrrolidone (PVP) and 40 g of FeCl 3 Stir. Centrifuge for 10 min and dry in a vacuum drying oven for 8 h to obtain the iron-carbon core-shell precursor Fe 0 @C.

[0087] (2) Place the Fe 0 @C core-shell material precursor obtained in step (1) in a tubular furnace and under N 2 atmosphere, calcine at 700 °C for 4 h to obtain the iron-carbon core-shell material.

[0088] (3) Dissolve 40 g of cerium nitrate in 500 mL of ammonia water with a concentration of 15% and stir well for 20 min. After the cerium nitrate is fully dissolved, add the Fe 0 @C core-shell material prepared in step (2) thereto, stir for 2 h, then centrifuge and dry in a vacuum drying oven for 3 h. Finally, place it in a tubular furnace and calcine at 1000 °C for 3 h to obtain Fe 0 @C@CeO 2 ORP regulation and slow-release materials.

[0089] The prepared Fe 0 @C@CeO 2 ORP regulation and slow-release materials are used to regulate the long-term stability of the ORP of wastewater in an anaerobic degradation system, improve the pollutant degradation ability of the anaerobic degradation system, and construct an excellent microbial community in the anaerobic degradation system.

[0090] The present invention is not limited to the above embodiments. For those of ordinary skill in the art of this technology, after learning the content recorded in the present invention, without departing from the principle of the present invention, several equivalent transformations and substitutions can also be made thereto, and these equivalent transformations and substitutions should also be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing an ORP-regulated sustained-release material, characterized in that: The following steps are involved: 1) Preparation of iron-carbon core-shell precursor: the biomass is crushed and added to deoxygenated purified water, and then polyvinyl pyrrolidone is added, and then iron salt is added and stirred; the mixture is dried after centrifugation to obtain the iron-carbon core-shell precursor; the mass concentration of the polyvinyl pyrrolidone in the reaction system is 0.5%~1%, and the mass ratio of the iron salt to the biomass is (1~20):1; 2) Preparation of iron-carbon core-shell material: the iron-carbon core-shell precursor is calcined under N2 atmosphere to obtain the iron-carbon core-shell material; 3) Fe 0 Preparation of @C@CeO2 sustained-release material: Dissolve cerium nitrate in ammonia water, add iron-carbon core-shell material, the mass ratio of cerium nitrate to iron-carbon core-shell material is 1: (1~10), stir, centrifuge and dry, and finally calcine to obtain ORP controlled sustained-release material.

2. The method for preparing the ORP controlled sustained-release material according to claim 1, characterized in that: The biomass is tea residue, rice straw residue, coconut shell or wax gourd peel.

3. The method for preparing the ORP controlled sustained-release material according to claim 1, characterized in that: The mesh size of the biomass after crushing is 500-2500 meshes.

4. The method for preparing the ORP controlled sustained-release material according to claim 1, characterized in that: The iron salt is ferric sulfate, ferric nitrate or ferric chloride.

5. The method for preparing the ORP controlled sustained-release material according to claim 1, characterized in that: The mass ratio of the iron salt to the biomass is (1-10):1; the centrifugation time is 5-20 min, and the vacuum drying time is 8 h-24 h.

6. The method for preparing the ORP controlled sustained-release material according to claim 1, characterized in that: In the step 2), the calcination temperature is 400-900°C and the reaction time is 1-8 h.

7. The method for preparing the ORP controlled sustained-release material according to claim 1, characterized in that: In the step 3), the calcination temperature is 600-1000°C and the reaction time is 1-8 h.

8. The ORP controlled sustained-release material obtained by the method according to any one of claims 1 to 7.

9. Use of the ORP controlled slow-release material according to claim 8 in an electrochemical catalytic system.

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