A method for preparing a porous silicon-based composite metal oxide catalytic module and its application in degrading geosmin

Abstract

The present invention discloses a method for preparing a porous silicon-based composite metal oxide catalytic module and its application in degrading geosmin. A silicon-based spinning solution containing a pore-forming template and a titanium wire mesh receiving electrode are used, and a porous silicon-based iron-cerium composite metal oxide electrospun fiber layer is prepared through an electrospinning process, a heat treatment process, and an impregnation process; the catalytic module uses a sand core filter as a supporting bracket and a safety filter, supplemented by an ultraviolet light source to further improve the catalytic efficiency. The porous silicon-based composite metal oxide catalytic module of the present invention is used to degrade geosmin in water, which solves the problems of weak antioxidant performance, low specific surface area, and low catalyst loading rate of traditional electrospun fiber membranes, and also effectively avoids the problem of secondary pollution caused by the loss of conventional catalysts or carriers. At the same time, most of the materials can be recycled and reused, which improves the economic efficiency of the application of the present invention.

Description

Technical Field

[0001] The present invention relates to a technology for treating odorous substances in drinking water, and in particular to a method for preparing a porous silicon-based composite metal oxide catalytic module and an application thereof in degrading geosmin. Background Art

[0002] The odor problem of drinking water is a common problem today, and the occurrence of odor incidents in natural water bodies is seasonal and sudden. For example, when the seasons alternate between spring and summer or autumn and winter, odor problems caused by the rapid reproduction of algae are prone to occur, which seriously affects the taste of drinking water. Therefore, the odor problem of drinking water is receiving more and more widespread discussion and attention.

[0003] How to control or remove odorous substances in drinking water is currently a difficult problem and research hotspot in the field of water quality safety assurance. In addition to in-situ treatment of water sources through ecological technologies, such as controlling eutrophication of water bodies and controlling the reproduction of algae and bacteria, odorous substances can also be removed through water treatment processes. However, the conventional treatment processes of water plants are not ideal for treating odorous substances in water.

[0004] Geosmin(C 12 H 22 Geosmin is one of the most common algae-derived odorants in drinking water and is an important source of earthy musty odors in water. Geosmin is primarily derived from the metabolic processes of algae and actinomycetes. Geosmin is a saturated tertiary cyclic alcohol with a very stable structure and strong resistance to degradation. Studies have shown that conventional water treatment processes and conventional oxidants such as potassium permanganate, sodium hypochlorite, ozone, and hydrogen peroxide are ineffective in removing it. Therefore, researchers are developing advanced oxidation technologies based on conventional chemical oxidation, which combine the use of catalysts or catalytic methods with oxidants to further improve the efficiency of chemical oxidation.

[0005] Ozone is one of the safer advanced oxidants in the field of water treatment technology. Its decomposition products are oxygen molecules. No other ions are produced during the reaction, which has little impact on water bodies and is relatively easy to prepare. Ozone can oxidize organic pollutants in water bodies through direct oxidation by ozone molecules and indirect oxidation by hydroxyl radicals. During the oxidation process, the ozone dosage, pollutant concentration, reaction temperature, solution pH value, etc. have a significant impact on the removal efficiency of organic pollutants. In the application of ozone treatment of actual water bodies, especially the treatment of drinking water, due to the large amount of water to be treated, water quality conditions such as water temperature, pH value, and pollutant concentration are usually unable to be adjusted. Instead, the treatment effect is often improved by adjusting process parameters such as ozone dosage and addition method. The mass transfer effect of ozone in water is affected by the dosage and addition method and has its limits. Therefore, some researchers have considered adding solid catalysts to the ozone oxidation reaction to further improve the reaction effect.

[0006] Currently, the solid materials commonly used for ozone catalysis are mainly metal oxides and carbon-based materials; metal oxides include single metal oxides, composite metal oxides, loaded metal oxides, etc.; carbon-based materials mainly include activated carbon, carbon nanotubes, graphene, etc.; carbon-based materials are complex and expensive to produce, while metal oxides are widely available, have simple production processes and are inexpensive, and therefore have been widely studied; metal oxides commonly used as environmental catalysts include iron oxides, copper oxides, manganese oxides and titanium dioxide, etc.

[0007] Single metal oxides as ozone catalysts often have the disadvantages of low specific surface area, few active sites, and easy agglomeration. Composite metal oxides, due to the diversity of their crystal structure and electronic structure, can accommodate multiple metal ions at the same time. The metals mainly promote the formation of oxygen vacancies and accelerate the electron transfer rate between different redox pairs, thereby improving the redox ability and catalytic activity. Supported metal oxides generally have a larger specific surface area, which can effectively increase the density of catalytically active components. In addition, some supports can cooperate with the supported metal oxides to promote the conversion of ozone to generate highly oxidizing, low-selective active oxygen species, thereby improving the removal efficiency of organic pollutants in water. Generally speaking, the catalytic efficiency of metal oxides for ozone is generally: supported metal oxides > composite metal oxides > single metal oxides.

[0008] Despite their excellent catalytic performance, these powdered catalysts are often in the laboratory research stage and have limited practical application in actual water treatment. They are difficult to recycle and have problems of secondary pollution. To solve these problems, carrier materials are often used to load the catalysts. Common carriers in engineering include activated carbon particles, ceramsite, alumina particles, honeycomb ceramics, etc. However, these carrier materials generally have problems such as small specific surface area, small amount of active metals that can be loaded, and low catalytic efficiency.

[0009] The catalytic efficiency of a catalyst depends to a certain extent on the structural properties of the catalyst and the carrier. Generally speaking, the smaller the particle size of the catalyst, the larger the specific surface area, and the higher the catalytic activity; the smaller the size of the catalyst carrier, the larger the specific surface area, the higher the catalyst loading, and the higher the catalytic efficiency.

[0010] To address the challenges of low surface area and loading efficiency commonly encountered in engineering applications, researchers have turned their attention to electrospun fibers, micro- and nano-materials that possess a specific catalyst loading capacity while maintaining a defined macroscopic morphology. Electrospun fibers can be fabricated into continuous micro- and nano-fibers from a variety of polymers and composite materials through electrospinning. These fibers are widely used in a wide range of fields, including tissue engineering, controlled drug delivery, water treatment, optoelectronic devices, energy storage devices, and flexible electronics, garnering significant attention from both academia and industry. In recent years, electrospun fibers have been increasingly investigated for applications in membrane filtration, oil-water separation, adsorption (of dyes, heavy metals, etc.), and antimicrobial applications in aquatic environmental protection. Electrospinning (electrospinning) offers advantages such as simplicity, low cost, and continuous preparation. Furthermore, the fiber structure and surface functional properties can be flexibly tuned by varying the electrospinning solution composition, electrospinning conditions, or post-treatment. However, due to the limited surface area of ​​conventional electrospun fibers and the fact that they are often composed of organic polymers with poor antioxidant properties, the development of highly active and durable catalysts remains a key challenge in the application of catalytic ozone oxidation technology. Summary of the Invention

[0011] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for preparing a porous silicon-based composite metal oxide catalytic module and its application in degrading geosmin. This method addresses the weak antioxidant properties, low specific surface area, and low catalyst loading of conventional electrospun fiber membranes, while also effectively avoiding secondary pollution caused by loss of conventional catalysts or carriers. Furthermore, the porous silicon-based composite metal oxide catalytic module of the present invention effectively degrades geosmin in water.

[0012] According to the present invention, a method for preparing a porous silicon-based composite metal oxide catalytic module and its application in degrading geosmin are achieved through the following technical solutions:

[0013] A method for preparing a porous silicon-based composite metal oxide catalytic module, characterized in that the preparation method of the porous silicon-based composite metal oxide catalytic module is:

[0014] (1) A titanium wire mesh is used as a receiving electrode of an electrospinning device, a silicon-based spinning solution is passed through the electrospinning device, and is uniformly sprayed onto the surface of the titanium wire mesh. The mesh is dried in an oven and then calcined in a muffle furnace. After cooling to room temperature, the mesh is immersed in a mixed solution of iron-cerium metal salt and saturated. The mesh is taken out and drained, dried in an oven, and then calcined in a muffle furnace. After cooling to room temperature, a porous silicon-based iron-cerium composite metal oxide electrospun fiber layer is formed on the surface of the titanium wire mesh, and the titanium wire mesh and the porous silicon-based iron-cerium composite metal oxide electrospun fiber layer constitute a catalytic material layer;

[0015] (2) The sand core filter, catalytic material layer and light guide ring are sequentially installed in the fixed frame from right to left, the ultraviolet light source is connected to the outside of the fixed frame and connected to the light guide ring, and then multiple catalytic units are connected end to end, gaskets are placed at the connection to stop water, and water inlet and outlet interfaces are installed at the water inlet and outlet ends respectively. After fixing, it becomes a porous silicon-based composite metal oxide catalytic module.

[0016] Furthermore, the silicon-based spinning solution of step (1) uses tetraethyl orthosilicate TEOS as a silicon source, triblock copolymer P123 as a pore-forming template, polyvinylpyrrolidone PVP as a thickener, and anhydrous ethanol EtOH as a solvent, and the molar ratio of the four is 3:1:3:100 to 1:2:1:100.

[0017] Furthermore, the titanium wire mesh of step (1) has a titanium wire diameter of 18 to 26 μm and a titanium wire mesh pore size of 25 to 30 μm; the porous silicon-based iron-cerium composite metal oxide electrospun fiber layer has a thickness of 10 to 20 μm, the electrospun fiber diameter is 0.6 to 3 μm, the pore size on the electrospun fiber is 0.01 to 0.2 μm, and the molar ratio of iron to cerium elements in the iron-cerium composite metal oxide loaded by the porous silicon-based electrospun fiber is 1:2 to 2:1.

[0018] Furthermore, the molar ratio of iron to cerium elements in the iron-cerium metal salt mixed solution of step (1) is 1:2 to 2:1, the immersion time is 6 to 12 hours, and the immersion temperature is 35 to 45°C.

[0019] Furthermore, the drying temperature of step (1) is 100-120° C., the drying time is 6-12 h, and the vacuum degree is -0.1-0.2 MPa.

[0020] Furthermore, the calcination temperature of step (1) is 500-650° C., the calcination time is 4-6 hours, and the gas atmosphere is air.

[0021] Furthermore, the sand core filter in step (2) has a thickness of 10 to 20 mm and a pore size of 1 to 1.5 μm.

[0022] Furthermore, the wavelength of the ultraviolet light source in step (2) is 172 to 365 nm.

[0023] An application of a porous silicon-based composite metal oxide catalytic module for degrading geosmin is characterized in that the degradation process of the porous silicon-based composite metal oxide catalytic module for geosmin is as follows: ozone is added to raw water containing geosmin, mixed evenly, and then flows into the porous silicon-based composite metal oxide catalytic module, the ozone in the water oxidatively degrades the geosmin, and after the reaction is completed, the water flows out of the porous silicon-based composite metal oxide catalytic module.

[0024] Furthermore, the ozone concentration is 6-8wt%, the dosage is 0.1-0.3mg / L, the reaction time is 2-5min, the unit ultraviolet light wavelength is 172-365nm, and the ultraviolet power is 2-4W / L.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] Using silicon-based materials as the main component of the fiber and forming a porous structure on the fiber surface solves the problem of weak antioxidant performance of traditional electrospun fiber membranes, and can also greatly improve the specific surface area, pore volume and catalyst loading rate; in addition, the porous material has microstructural defects, which is conducive to light scattering and improves photocatalytic efficiency; using metal titanium wire mesh as the electrospinning receiving electrode, and guiding the arrangement of electrospun fibers through conductive metal titanium wire to avoid the water channel (grid gap) being completely covered by the electrospun fibers; through heat treatment, the electrospun fibers are effectively fixed to the metal titanium wire mesh, and a sand core filter is used as a support bracket for the titanium wire mesh, which not only solves the problem that conventional electrospun fibers cannot be fixed, but also can alleviate water flow impact and intercept accidentally lost electrospun fibers, which can effectively avoid the problem of secondary pollution.

[0027] The main materials used in the present invention are iron, cerium, titanium and silicon, which are widely available and relatively inexpensive; the catalytic material carrier (porous silicon-based electrospun fiber + titanium wire mesh + sand core filter) has strong antioxidant ability and a long service life; when the catalytic material (iron-cerium composite oxide) fails, the porous silicon-based electrospun fiber layer and the titanium wire mesh can be mechanically peeled off, and the titanium wire mesh can be recycled, thereby improving the overall economic efficiency of the technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Electron microscope images of the surface structure of the catalytic material layer according to an embodiment of the present invention (a is an electron microscope image of the catalytic material layer, b is an electron microscope image of the porous silicon-based electrospun fiber layer, and c is an electron microscope image of the porous silicon-based iron-cerium composite metal oxide electrospun fiber)

[0029] Figure 2 This is an electron microscope schematic diagram of the surface structure of the catalytic material layer according to an embodiment of the present invention;

[0030] Figure 3 Schematic cross-sectional view of the catalytic unit structure of an embodiment of the present invention;

[0031] Figure 4 Schematic diagram of a catalytic unit structure in a plan view according to an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of the cross-section of the catalytic module structure according to an embodiment of the present invention.

[0033] Reference numerals:

[0034] Catalytic material layer 102: titanium wire mesh 112, porous silicon-based iron-cerium composite metal oxide electrospun fiber layer 122 Catalytic unit 110: fixed frame 101, catalytic material layer 102, light guide ring 103, gasket 104, ultraviolet light source 105, sand core filter 106

[0035] Porous silicon-based composite metal oxide catalytic module 200: n catalytic units 110, water inlet interface 120, water outlet interface 130 DETAILED DESCRIPTION

[0036] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0037] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0038] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0039] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0040] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] The preparation method of the porous silicon-based composite metal oxide catalytic module is as follows: a titanium wire mesh 112 is used as a receiving electrode of an electrospinning device, a silicon-based spinning solution is uniformly sprayed onto the surface of the titanium wire mesh 112 through the electrospinning device, the solution is dried in an oven, and then calcined in a muffle furnace. After cooling to room temperature, the solution is saturated in a mixed solution of iron-cerium metal salts, taken out and drained, dried in an oven, and then calcined in a muffle furnace. After cooling to room temperature, a porous silicon-based iron-cerium composite metal oxide electrospun fiber layer 122 is formed on the surface of the titanium wire mesh 112, and the two constitute the catalytic material layer 102. Figure 1 and Figure 2 shown.

[0042] like Figure 3 and Figure 4 and Figure 5 As shown, a sand core filter 106, a catalytic material layer 102 and a light guide ring 103 are sequentially installed in the fixed frame 101 from right to left, an ultraviolet light source 105 is connected to the outside of the fixed frame 101 and connected to the light guide ring 103, and then multiple catalytic units 110 are connected end to end, a gasket 104 is placed at the connection to stop water, and a water inlet interface 120 and a water outlet interface 130 are installed at the water inlet and outlet ends respectively. After being fixed, it becomes a porous silicon-based composite metal oxide catalytic module 200.

[0043] The degradation process of geosmin by the porous silicon-based composite metal oxide catalytic module 200 is as follows: ozone is added to the raw water containing geosmin, mixed evenly, and then flows into the porous silicon-based composite metal oxide catalytic module 200. The ozone in the water oxidizes and degrades the geosmin. After the reaction is completed, the water flows out of the porous silicon-based composite metal oxide catalytic module 200.

[0044] In Examples 1 to 3, the above-mentioned porous silicon-based composite metal oxide catalytic module 200 is used for treatment.

[0045] Example 1

[0046] In this embodiment, the process parameters for treating the effluent from the sand filter of a water plant in Shaoguan City (containing geosmin) are: treatment capacity 15m 3 / h, ozone concentration is 8wt%, dosage is 0.1mg / L, reaction time is 5min, ultraviolet light wavelength is 256nm, unit ultraviolet power is 2W / L, inlet geosmin content is 35ng / L, and outlet geosmin content is 2.0ng / L.

[0047] Example 2

[0048] In this embodiment, the process parameters for treating the effluent from the sand filter of a water plant in Guangzhou (containing geosmin) are: treatment capacity 7.5m 3 / h, ozone concentration is 8wt%, dosage is 0.12mg / L, reaction time is 5min, ultraviolet light wavelength is 256nm, unit ultraviolet power is 2W / L, inlet geosmin content is 63ng / L, and outlet geosmin content is 3.1ng / L.

[0049] Example 3

[0050] In this embodiment, the process parameters for treating the effluent from the sand filter of a water plant in Zhuhai (containing geosmin) are: treatment capacity 7.5m 3 / h, ozone concentration is 7.5wt%, dosage is 0.15mg / L, reaction time is 5min, ultraviolet light wavelength is 256nm, unit ultraviolet power is 2W / L, inlet geosmin content is 81ng / L, and outlet geosmin content is 4.2ng / L.

[0051] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. An application of a porous silicon-based composite metal oxide catalytic module for degrading geosmin, characterized in that: The porous silicon-based composite metal oxide catalytic module is used to degrade geosmin, comprising the following steps: Ozone is added to raw water containing geosmin, mixed evenly, and then flows into the porous silicon-based composite metal oxide catalytic module (200), where the ozone in the water oxidizes and degrades the geosmin. After the reaction is completed, the water flows out of the porous silicon-based composite metal oxide catalytic module (200); the ozone concentration is 6-8 wt%, the dosage is 0.1-0.3 mg / L, and the reaction time is 2-5 min; The preparation method of the porous silicon-based composite metal oxide catalytic module is as follows: (1) A titanium wire mesh (112) is used as a receiving electrode of an electrospinning device, a silicon-based spinning solution is uniformly sprayed onto the surface of the titanium wire mesh (112) through the electrospinning device, the titanium wire mesh (112) is dried in an oven, and then calcined in a muffle furnace. After cooling to room temperature, the titanium wire mesh (112) is immersed in a mixed solution of iron-cerium metal salts, taken out and drained, dried in an oven, and then calcined in a muffle furnace. After cooling to room temperature, a porous silicon-based iron-cerium composite metal oxide electrospun fiber layer (122) is formed on the surface of the titanium wire mesh (112), and the titanium wire mesh (112) and the porous silicon-based iron-cerium composite metal oxide electrospun fiber layer (122) constitute a catalytic material layer (102); (2) The sand core filter (106), the catalytic material layer (102) and the light guide ring (103) are sequentially installed in the fixed frame (101) from right to left, the ultraviolet light source (105) is connected to the outside of the fixed frame (101) and connected to the light guide ring (103), and then the multiple catalytic units (110) are connected end to end, and gaskets (104) are placed at the connection to stop water, and the water inlet interface (120) and the water outlet interface (130) are respectively installed at the water inlet and outlet ends. After fixing, it becomes a porous silicon-based composite metal oxide catalytic module (200); In step (1), the porous silicon-based iron-cerium composite metal oxide electrospun fiber layer (122) has a thickness of 10-20 μm, the diameter of the electrospun fiber is 0.6-3 μm, the pore size of the electrospun fiber is 0.01-0.2 μm, the molar ratio of iron to cerium in the iron-cerium composite metal oxide loaded on the porous silicon-based electrospun fiber is 1:2-2:1; the molar ratio of iron to cerium in the iron-cerium metal salt mixed solution is 1:2-2:1, the immersion time is 6-12 h, and the immersion temperature is 35-45° C.; In step (2), the wavelength of the ultraviolet light source (105) is 172-365 nm, and the ultraviolet power is 2-4 W / L.

2. The application according to claim 1, characterized in that In step (1), the silicon-based spinning solution comprises tetraethyl orthosilicate (TEOS) as a silicon source, triblock copolymer (P123) as a pore-forming template, polyvinylpyrrolidone (PVP) as a thickener, and anhydrous ethanol (EtOH) as a solvent, and the molar ratio of the four is 3:1:3:100 to 1:2:1:

100.

3. The application according to claim 1, characterized in that In step (1), the titanium wire mesh (112) has a titanium wire diameter of 18 to 26 μm and a titanium wire mesh aperture of 25 to 30 μm.

4. The application according to claim 1, characterized in that In step (1), the drying temperature is 100-120°C, the drying time is 6-12 hours, and the vacuum degree is -0.1 MPa.

5. The application according to claim 1, characterized in that: In step (1), the calcination temperature is 500-650° C., the calcination time is 4-6 hours, and the gas atmosphere is air.

6. The application according to claim 1, characterized in that: In step (2), the thickness of the sand core filter is 10-20 mm and the pore size is 1-1.5 μm.

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