A sulfur-iron oxide composite denitrification packing, its preparation method and application

Abstract

This invention discloses a sulfur-iron oxide composite denitrification packing, its preparation method, and its application, relating to the field of wastewater treatment technology. The packing comprises: sulfur powder, siderite, magnesite, magnesium oxide, metallic manganese, metallic aluminum, nano-iron, boron sludge, magnetite, and a binder. The total amount of metallic manganese, metallic aluminum, and nano-iron added constitutes 8% to 16% of the mass of the sulfur-iron oxide composite denitrification packing. This invention alleviates the technical problems of insufficient strength and wear resistance, as well as low denitrification efficiency in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a sulfur-iron oxide composite denitrification packing, its preparation method, and its application. Background Technology

[0002] Traditional heterotrophic denitrification suffers from drawbacks such as high carbon source consumption and high sludge production. In contrast, sulfur autotrophic denitrification, as an inorganic denitrification technology, can achieve deep denitrification without the need for an external carbon source, showing broad application prospects in the field of low-carbon and high-efficiency denitrification and becoming one of the core directions for the iterative upgrading of wastewater biological denitrification technology. Existing sulfur-iron oxide composite denitrification packing materials are mainly prepared from siderite, sulfur powder, and magnesite. This packing material utilizes reduced sulfur (S)... 0 Iron serves as the primary electron donor, with NO3 as the main source. - -N acts as an electron acceptor, and simultaneously gains energy through the redox reaction of sulfur, converting NO3- into... - -N is reduced to nitrogen gas. The sulfur autotrophic denitrification process consumes alkalinity, while the complex minerals provide alkalinity. By combining the two and controlling a certain ratio, the denitrification system can be maintained.

[0003] However, the sulfur-iron oxide composite denitrification packing material prepared under existing granulation technology suffers from low enrichment of denitrifying microorganisms and low denitrification efficiency, with the packing material's denitrification efficiency generally ranging from 0.4 to 0.6 kgN / m³. 3 / d, the denitrification efficiency decreases over time and cannot remain stable. Furthermore, the strength and wear resistance of the packing are insufficient. In actual engineering projects, excessive wear of the packing results in ineffective loss of the packing. The lost sulfur autotrophic packing accumulates in the pipeline and, under anaerobic conditions, is reduced to hydrogen sulfide by sulfate-reducing bacteria, producing odor and corroding the pipeline. Summary of the Invention

[0004] The purpose of this invention is to provide a sulfur-iron oxide composite denitrification packing, its preparation method, and its application in order to solve at least one of the above-mentioned technical problems.

[0005] In a first aspect, embodiments of the present invention provide a sulfur-iron oxide composite denitrification packing material, comprising: sulfur powder, siderite, magnesite, magnesium oxide, metallic manganese, metallic aluminum, nano-iron, boron mud, magnetite, and a binder; wherein the sum of the amounts of metallic manganese, metallic aluminum, and nano-iron added accounts for 8% to 16% of the mass percentage of the sulfur-iron oxide composite denitrification packing material.

[0006] Furthermore, the boron mud comprises a mixture of silicon dioxide, boron trioxide, and aluminum oxide.

[0007] Furthermore, the sulfur powder has a particle size greater than 130 mesh.

[0008] Furthermore, the particle size of the siderite, the magnesite, and the magnetite is 50 mesh to 120 mesh.

[0009] Furthermore, the binder comprises any one or more combinations of the following: diatomaceous earth, gypsum, silicate cement, quartz sand, and kaolin.

[0010] Furthermore, the mass percentages of the sulfur powder, the siderite, the magnesite, the magnetite, the boron mud, and the binder in the sulfur-iron oxide composite denitrification filler are respectively 28%~60%, 5%~30%, 5%~25%, 3%~10%, 3%~15%, and 5%~15%.

[0011] Secondly, embodiments of the present invention also provide a method for preparing a sulfur-iron oxide composite denitrification packing, comprising: uniformly mixing sulfur powder, siderite, magnesite, magnesium oxide, metallic manganese, metallic aluminum, nano-iron, boron mud, magnetite, and a binder according to a preset mass ratio to obtain an initial denitrification packing; adding water to the initial denitrification packing and continuing to mix, and molding the raw material by extrusion granulation or disc granulation to obtain a shaped denitrification packing; drying the shaped denitrification packing to obtain a dried denitrification packing; and sintering the dried denitrification packing to obtain the sulfur-iron oxide composite denitrification packing.

[0012] Further, the dried denitrification packing is subjected to sintering treatment to obtain the sulfur-iron oxide composite denitrification packing, including: placing the dried denitrification packing in a calcining furnace for a first sintering treatment to obtain a first-calcined denitrification packing; placing the first-calcined denitrification packing in a vacuum sintering furnace for a second sintering treatment to obtain the sulfur-iron oxide composite denitrification packing; wherein, an inert gas is introduced during the second sintering treatment.

[0013] Thirdly, embodiments of the present invention also provide an application of sulfur-iron oxide composite denitrification packing in wastewater treatment, wherein the sulfur-iron oxide composite denitrification packing is used in the sulfur autotrophic denitrification process.

[0014] This invention provides a sulfur-iron oxide composite denitrification packing, its preparation method, and its application. The packing incorporates metallic manganese and nano-iron, enhancing the removal of nitrogen by functional microorganisms utilizing iron. The components of the packing, magnetite and metallic manganese, promote the enrichment of functional microorganisms such as *Thiobacillus denitrifyingus* and *Vibrio denitrifyingus*, indirectly strengthening the removal of nitrogen by microorganisms utilizing sulfur. The preparation method employs a secondary sintering process, further improving the packing's strength and reducing its breakage and wear rates during use. This invention alleviates the technical problems of insufficient strength and wear resistance, as well as low denitrification efficiency in existing technologies. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 A flowchart illustrating a method for preparing a sulfur-iron oxide composite denitrification packing provided in an embodiment of the present invention;

[0017] Figure 2 A schematic diagram illustrating the denitrification efficiency of the sulfur-iron oxide composite denitrification packing obtained by the preparation method provided in the embodiments of the present invention;

[0018] Figure 3 This is a schematic diagram of a water treatment experimental apparatus provided in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a sulfur-iron oxide composite denitrification packing material, comprising: sulfur powder, siderite, magnesite, magnesium oxide, metallic manganese, metallic aluminum, nano-iron, boron mud, magnetite, and a binder; wherein,

[0021] The combined amount of added manganese, aluminum and nano-iron accounts for 8% to 16% of the mass of the sulfur-iron oxide composite denitrification packing.

[0022] Specifically, in this embodiment of the invention, the boron mud comprises a mixture of silicon dioxide, boron trioxide, and aluminum oxide.

[0023] Preferably, the sulfur powder has a particle size greater than 130 mesh.

[0024] Preferably, the particle size of siderite, magnesite, and magnetite is 50 mesh to 120 mesh.

[0025] Preferably, the binder comprises any one or more combinations of the following: diatomaceous earth, gypsum, silicate cement, quartz sand, and kaolin. For example, the binder may be diatomaceous earth or kaolin, or it may be a mixture of gypsum, silicate cement, and quartz sand.

[0026] Preferably, the mass percentages of sulfur powder, siderite, magnesite, magnetite, boron mud, and binder in the sulfur-iron oxide composite denitrification filler are 28%~60%, 5%~30%, 5%~25%, 3%~10%, 3%~15%, and 5%~15%, respectively.

[0027] Specifically, the main component of magnetite is Fe3O4, which is composed of Fe... 2+ and Fe 3+ Together they form a composite oxide of FeO·Fe2O3.

[0028] This invention provides a fluid oxide composite denitrification packing material, which is prepared by adding metallic manganese and Fe to the raw materials. 2+ Nano-iron provides sufficient reducing power for the denitrification filler; by adding metallic manganese, it reacts with Fe... 2+ Fe 3+ A redox reaction occurs, reducing the oxidized Fe element and giving the denitrification filler a more durable reducing property. The specific chemical reaction formula is as follows:

[0029] Fe 3+ +e⁻→Fe 2+

[0030] Mn+2Fe 3+ →Mn 2+ +2Fe 2+

[0031] Fe 2+ +2e⁻→Fe

[0032] Mn+Fe 2+ →Mn 2+ +Fe

[0033] Meanwhile, the iron-manganese reaction forms a galvanic cell system, which accelerates electron transfer efficiency, helps to speed up the reaction rate of functional microorganisms, and improves the denitrification effect.

[0034] Figure 1 This is a flowchart illustrating a method for preparing a sulfur-iron oxide composite denitrification packing according to an embodiment of the present invention. Figure 1 As shown, the method specifically includes the following steps:

[0035] In step S102, sulfur powder, siderite, magnesite, magnesium oxide, metallic manganese, metallic aluminum, nano iron, boron mud, magnetite, and binder are mixed uniformly according to a preset mass ratio to obtain the initial denitrification filler.

[0036] The preset quality percentages include:

[0037] The combined amount of added manganese, aluminum, and nano-iron accounts for 8% to 16% of the mass of the sulfur-iron oxide composite denitrification packing.

[0038] The mass percentages of sulfur powder, siderite, magnesite, magnetite, boron mud, and binder in the sulfur-iron oxide composite denitrification packing are 28%~60%, 5%~30%, 5%~25%, 3%~10%, 3%~15%, and 5%~15%, respectively.

[0039] In step S104, water is added to the initial denitrification packing and mixed further. The raw material is then shaped using extrusion granulation or disc granulation to obtain the shaped denitrification packing.

[0040] Step S106: The molded denitrification packing is dried to obtain the dried denitrification packing.

[0041] Specifically, the molded denitrification filler is placed in an oven for drying.

[0042] Preferably, the drying temperature includes, but is not limited to, 160°C and 180°C; the drying time includes, but is not limited to, 45 min and 120 min.

[0043] Step S108: The dried denitrification packing is sintered to obtain sulfur iron oxide composite denitrification packing.

[0044] Specifically, step S108 further includes the following steps:

[0045] Step S1081: The dried denitrification packing is placed in a calcination furnace for a first sintering treatment to obtain a first-calcined denitrification packing.

[0046] Specifically, the dried denitrification packing is placed in a calcination furnace and calcined at 350°C for 2.5 hours to obtain a single-calcination denitrification packing.

[0047] Step S1082: The primary calcined denitrification packing is placed in a vacuum sintering furnace for secondary sintering treatment to obtain sulfur iron oxide composite denitrification packing; wherein, inert gas is introduced during the secondary sintering process.

[0048] Specifically, after the first-calcined denitrification filler is cooled to room temperature, it is placed in a vacuum sintering furnace and heated to 420°C at a rate of 5°C / min and held for 2.5 hours, then heated to 500°C and held for 6.5 hours, and finally heated to 600°C and held for 9 hours. Inert gas is introduced for protection during the sintering process.

[0049] Preferably, the temperature control accuracy of the vacuum sintering furnace is ±5℃, and the inert gas is argon.

[0050] The preparation method provided in this invention employs a vacuum sintering furnace for secondary sintering, equipped with a high-precision temperature control system (temperature control accuracy ±5℃) to ensure temperature uniformity within the furnace. Vacuum is achieved through vacuuming or the introduction of an inert gas (such as argon). The temperature is first increased to 420℃ at a rate of 5℃ / min, held for 2.5 hours to remove adsorbed water, and then increased to the target temperature to reduce the risk of powder explosion. Holding at 500℃ for 6.5 hours promotes the initial reaction, followed by increasing the temperature to 600℃ to accelerate diffusion. Holding at 600℃ for 9 hours allows manganese and aluminum atoms to diffuse and form the Al6Mn phase, giving the denitrification filler excellent strength, hardness, and wear resistance.

[0051] Figure 2 This is a schematic diagram illustrating the denitrification efficiency of the sulfur-iron oxide composite denitrification packing obtained by the preparation method provided in the embodiments of the present invention. Figure 3 This is a schematic diagram of a water treatment experimental apparatus provided in an embodiment of the present invention. Figure 2 As shown, the sulfur-iron oxide composite denitrification packing obtained by the preparation method provided in the embodiments of the present invention has high denitrification efficiency, as shown in... Figure 3 NO3 after the experimental setup shown has been running for more than 10 days - The removal rate of nitrogen (N) can be consistently maintained above 97%. Meanwhile, at a water temperature of 20℃, the denitrification load of the packing material remains stable within the range of 1.43-1.82 kgN / m³ / d. Furthermore, the breakage and wear rates during use are low, with an average breakage rate plus wear rate of 0.03%.

[0052] This invention also provides an application of sulfur-iron oxide composite denitrification packing in wastewater treatment, wherein the sulfur-iron oxide composite denitrification packing is used in the sulfur autotrophic denitrification process.

[0053] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0054] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a sulfur-iron oxide composite denitrification packing, characterized in that, include: Sulfur powder, siderite, magnesite, magnesium oxide, metallic manganese, metallic aluminum, nano iron, boron mud, magnetite, and binder are mixed uniformly according to a preset mass ratio to obtain the initial denitrification filler. Water is added to the initial denitrification packing and mixed further. The raw material is then shaped using extrusion granulation or disc granulation to obtain the shaped denitrification packing. The molded denitrification packing is dried to obtain the dried denitrification packing. The dried denitrification packing is subjected to sintering treatment to obtain the sulfur iron oxide composite denitrification packing; The dried denitrification packing is sintered to obtain the sulfur-iron oxide composite denitrification packing, comprising: The dried denitrifying packing is placed in a calcining furnace for a primary sintering treatment to obtain a primary calcining denitrifying packing. The primary calcined denitrification packing is placed in a vacuum sintering furnace for secondary sintering treatment to obtain the sulfur iron oxide composite denitrification packing; In the secondary sintering process, an inert gas is introduced. The secondary sintering process includes: first, heating to 420°C at a rate of 5°C / min, holding at that temperature for 2.5 hours to remove adsorbed water, then heating to the target temperature, holding at 500°C for 6.5 hours to promote the initial reaction, then heating to 600°C to accelerate diffusion, and holding at 600°C for 9 hours.

2. A sulfur-iron oxide composite denitrification packing prepared by the method described in claim 1, characterized in that, include: Sulfur powder, siderite, magnesite, magnesium oxide, metallic manganese, metallic aluminum, nano-iron, boron mud, magnetite, and binder; among which, The sum of the amounts of the added metallic manganese, metallic aluminum, and nano-iron accounts for 8% to 16% of the mass of the sulfur-iron oxide composite denitrification filler. The mass percentages of the sulfur powder, the siderite, the magnesite, the magnetite, the boron mud, and the binder in the sulfur-iron oxide composite denitrification filler are 28%~60%, 5%~30%, 5%~25%, 3%~10%, 3%~15%, and 5%~15%, respectively.

3. The sulfur-iron oxide composite denitrification packing according to claim 2, characterized in that: The boron mud comprises a mixture of silicon dioxide, boron trioxide, and aluminum oxide.

4. The sulfur-iron oxide composite denitrification packing according to claim 2, characterized in that: The sulfur powder has a particle size greater than 130 mesh.

5. The sulfur-iron oxide composite denitrification packing according to claim 2, characterized in that: The siderite, magnesite, and magnetite have a particle size of 50 mesh to 120 mesh.

6. The sulfur-iron oxide composite denitrification packing according to claim 2, characterized in that: The binder includes any one or more of the following combinations: diatomaceous earth, gypsum, silicate cement, quartz sand, and kaolin.

7. The application of the sulfur-iron oxide composite denitrification packing material according to any one of claims 2-6 in wastewater treatment, characterized in that, The sulfur-iron oxide composite denitrification packing is used in the sulfur autotrophic denitrification process.

Images