Preparation method and device of core-shell structure light microsphere loaded titanium oxide film material

Abstract

The application relates to a preparation method of a core-shell structure light microsphere loaded titanium oxide film material, which comprises the following steps: step S1, mixing a titanium source, an alcohol solvent, water and an acid catalyst to form a titanium oxide sol through a hydrolysis condensation reaction; step S2, providing light microspheres; step S3, spraying the titanium oxide sol on the surface of the light microspheres by adopting a powder spraying and coating device, so that the light microspheres are attached with the titanium oxide sol to form wet composite powder; and step S4, drying and heat treating the wet composite powder to obtain the light microsphere loaded titanium oxide film material. The application also provides a powder spraying and coating device which comprises a spraying and coating chamber, a feeding and discharging opening, a spraying opening, a blower inlet, a filtrate valve, a spraying liquid filter membrane and a spraying liquid collecting container. The light microsphere loaded titanium oxide film material with a core-shell structure is constructed by taking the light microspheres as the core and the titanium oxide film as the shell layer, and the overall raw material cost of the functional material is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of water surface pollutant treatment materials, and specifically relates to a method and apparatus for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material. Background Technology

[0002] Water pollution poses a severe challenge to the environment and ecology, and the treatment of water pollutants is a global problem, including pollution of marine and inland lakes. Currently, the cost of floating materials for water pollution treatment remains high. Hollow glass microspheres, with their ultra-lightweight, high-strength, heat and sound insulation, electromagnetic wave transmission, and easily functionalized surface properties, are transformative materials in high-end manufacturing industries such as aerospace, automotive, deep-sea equipment, and building materials. With technological advancements, hollow glass microspheres are also playing an important role in environmental governance, particularly as lightweight floating materials with significant application potential in water pollutant treatment. Fly ash cenospheres, as a solid waste resource from coal-fired power plants, possess natural hollow structures, low density, high temperature resistance, high fluidity, and surface activity, achieving high-value applications in multiple industrial sectors, such as environmental governance, green building materials, and refractory materials.

[0003] Currently, how to utilize lightweight microsphere materials such as hollow glass microspheres or fly ash cenospheres (a derivative of industrial waste) at low cost to revalue them, realize the reuse of waste resources, and promote their continuous application in the environmental protection field is an important research direction in the field of water surface pollutant materials. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a method and apparatus for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material. The specific technical solution is as follows: This invention provides a method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material, the method comprising the following steps: Step S1: Mix titanium source, alcohol solvent, water and acid catalyst, and form titanium oxide sol through hydrolysis and condensation reaction; Step S2: Provide lightweight microspheres; Step S3: Using a powder spraying coating device, the titanium dioxide sol is sprayed onto the surface of the lightweight microspheres, so that the titanium dioxide sol adheres to the surface of the lightweight microspheres, forming a wet composite powder; Step S4: The wet composite powder is dried and heat-treated to obtain a lightweight microsphere-supported titanium dioxide film material.

[0005] As a preferred embodiment of the present invention, in step S1, the preparation of the titanium dioxide sol further includes adding a complexing agent and a leveling agent.

[0006] As a preferred technical solution of the present invention, step S1 involves mixing an appropriate amount of ethanol and acetylacetone, adding tetrabutyl titanate, stirring evenly in a water bath at 30-60°C, adjusting the pH of the mixture to 3-6 with concentrated HCl, adding deionized water, stirring for 1-3 hours, and then adding N,N-dimethylformamide to obtain titanium dioxide sol.

[0007] As a preferred embodiment of the present invention, the molar ratio of deionized water to tetrabutyl titanate is 1:1 to 9:1, and the titanium oxide solid content of the system is 0.5 to 10 wt%.

[0008] In a preferred embodiment of the present invention, the ethanol is anhydrous ethanol.

[0009] As a preferred technical solution of the present invention, step S4 involves collecting the wet composite powder and spray drying or transferring it into a vacuum drying oven, drying it at a temperature of 50~150℃ for 30~60 minutes, and then transferring the dried powder into a vacuum furnace for heat treatment at 350~450℃ for 30~120 minutes to obtain a lightweight microsphere-supported titanium dioxide film material.

[0010] As a preferred embodiment of the present invention, the lightweight microspheres are hollow glass microspheres or fly ash cenospheres.

[0011] As a preferred embodiment of the present invention, the diameter of the hollow glass microspheres or fly ash cenospheres is 50 nm to 50 μm.

[0012] The present invention also provides a powder spraying coating device, including a spraying coating chamber. The upper part of the spraying coating chamber is a cylindrical chamber with a feeding port and a spraying port respectively on the top surface of the chamber. The lower part is a conical chamber with a blower inlet on the side wall of the chamber. The bottom of the conical chamber has an opening with a filter valve. The top of the opening is detachably sealed with a spraying liquid filter membrane, and the bottom of the opening is connected to a spraying liquid collection container.

[0013] As a preferred embodiment of the present invention, the blower inlet is inclined downward at 45° to the vertical direction, and one blower inlet is provided on each of the left and right sides of the spray coating chamber, and the blower inlets are distributed in a rotationally symmetrical or axisily symmetrical manner with the spray coating chamber as the center of symmetry.

[0014] The beneficial effects of this invention are: 1. This invention uses hollow glass microspheres or fly ash cenospheres as the core, enabling the finished material to float stably on the water surface for a long period. This allows it to maintain maximum direct and continuous contact with pollutants on the water surface, solving the problem that traditional powder or sedimentation-type photocatalysts are difficult to effectively remain and function on the water surface. A titanium dioxide film layer formed by surface loading acts as the shell, providing photocatalytic activity to the material. This titanium dioxide film can generate strong oxidizing substances under light irradiation, which can efficiently degrade various organic pollutants on the water surface. The core-shell structure confines and loads the photocatalytically active components onto the surface of lightweight microspheres, avoiding internal masking or detachment of the active components during use, ensuring the durability and stability of the photocatalytic efficiency.

[0015] 2. This invention employs a powder spraying coating device to spray titanium dioxide sol onto the surface of dynamically dispersed lightweight microspheres. This achieves uniform adhesion and encapsulation of the sol on the microsphere surface, effectively preventing adhesion between microspheres and self-aggregation of titanium dioxide. The introduction of complexing and leveling agents during sol preparation helps improve the stability and spreadability of the sol, resulting in a more uniform, dense, and smooth initial wet film on the microsphere surface. Subsequent drying and heat treatment processes not only remove organic components but also promote the transformation of titanium dioxide from an amorphous state to a highly photocatalytically active crystalline state, and establish a strong chemical or physical bond between the film layer and the microsphere substrate, enhancing the mechanical stability and durability of the shell.

[0016] 3. This invention directly uses fly ash cenospheres, an industrial waste derivative, or hollow glass microspheres with relatively controllable costs as the carrier core, which significantly reduces the overall raw material cost of functional materials; the utilization of fly ash cenospheres realizes the high-value-added transformation of waste resources.

[0017] 4. The diameter of the lightweight microspheres selected in this invention is in the range of nanometers to micrometers; microspheres of this size have good fluidity and dispersibility, which facilitates the spray coating process and makes the final product easy to spread over a large area on the water surface and form a uniform covering layer. Attached Figure Description

[0018] Figure 1 The morphology of a typical sample prepared in Example 1 of this invention is shown; Figure 2 A front view of the powder spraying coating apparatus of the present invention is shown; Figure 3 A top view of the structure in which the two blower inlets of the powder spraying coating device of the present invention are arranged in a rotationally symmetrical manner is shown; Figure 4 A top view of the structure of the powder spraying coating device of the present invention, in which the two blower inlets are distributed in an axisymmetric manner, is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] The technical solution in this invention aims to solve the technical problems in the background art by proposing a method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material. The overall concept is as follows: This invention uses hollow glass microspheres or fly ash cenospheres as a floating carrier to prepare lightweight floating materials with photocatalytic properties, which have great application potential in the field of water surface pollution degradation. The hollow glass microspheres or fly ash cenospheres are coated to expand their functions and application areas. Inexpensive hollow glass microspheres or industrial waste derivative fly ash cenospheres are revalued through the method of this invention, realizing the reuse of waste resources and possessing high social value.

[0021] This invention constructs a core-shell structure of lightweight microspheres supporting titanium dioxide film, using lightweight microspheres as the core and a titanium dioxide film as the shell. First, a titanium source, alcohol solvent, water, and acid catalyst are mixed and subjected to a hydrolysis-condensation reaction to form a titanium dioxide sol. Then, using a powder spraying coating device, the titanium dioxide sol is sprayed onto the surface of the lightweight microspheres, causing the titanium dioxide sol to adhere to the surface of the microspheres, forming a wet composite powder. Finally, the wet composite powder is dried and heat-treated to obtain the lightweight microsphere-supported titanium dioxide film material.

[0022] In this invention, ethanol is used as the solvent; acetylacetone is used as a complexing agent to reduce the reaction intensity and make the reaction mild; N,N-dimethylformamide is used as a leveling agent to reduce film cracking; tetrabutyl titanate is used as the precursor for preparing titanium dioxide sol, and the preparation reaction process is as follows: Ti-(OC4H9)4+H2O → (H9C4O)3-Ti-OH+C4H9OH (H9C4O)3-Ti-OH+H2O →(H9C4O)2-Ti-(OH)2+ C4H9OH (H9C4O)2-Ti-(OH)2+H2O →(H9C4O)-Ti-(OH)3+ C4H9OH (H9C4O)-Ti-(OH)3+H2O →Ti-(OH)4+ C4H9OH Ti-(OH)4 → TiO2 + 2H2O To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0023] Example 1 300 mL of anhydrous ethanol and 10.6 mL of acetylacetone were mixed evenly, and 35 mL of tetrabutyl titanate was added. The mixture was stirred in a 40°C water bath for 30 min. The pH of the mixture was adjusted to approximately 2.0 with concentrated HCl, and 7.3 mL of deionized water was added. After stirring for 1–3 h, 10 mL of N,N-dimethylformamide was added to obtain titanium dioxide sol. The obtained titanium dioxide sol was used as a powder coating sol. Powder coating was performed using the powder spray coating device of this invention. 15 g of fly ash microspheres with a diameter of 50–200 nm were added. The coating spray gun nozzle diameter was 0.1 mm–0.9 mm, and the spray pressure was 0.1–0.9 MPa. The powder with titanium dioxide sol adhering to its surface after spray coating was collected and transferred to a vacuum drying oven and dried at 50~150 ℃ for 30~60 min. After drying, the powder was transferred to a vacuum furnace and heat-treated at 350~450 ℃ for 30~120 min to obtain a lightweight microsphere-supported titanium dioxide film material.

[0024] Example 2 4 L of anhydrous ethanol and 0.14 L of acetylacetone were mixed thoroughly, and then 0.47 L of tetrabutyl titanate was added. The mixture was stirred thoroughly in a 40°C water bath, and the pH of the mixture was adjusted to approximately 2.0 with concentrated HCl. 90 mL of deionized water was added, and the mixture was stirred for 1–3 h. Then, 0.13 L of N,N-dimethylformamide was added to obtain titanium dioxide sol. The obtained titanium dioxide sol was used as a powder coating sol, and powder spray coating was performed using the powder spray coating device of this invention. 250 g of hollow glass microspheres with a diameter of approximately 100 nm to 2 μm were added. The coating spray gun nozzle diameter was 0.1 mm to 0.9 mm, and the spray pressure was 0.1 to 0.9 MPa. The powder with titanium dioxide sol adhering to its surface after spray coating was collected and spray dried using a closed-loop circulation spray dryer with an inlet air temperature of 50–200°C and an outlet air temperature of 30–150°C. After drying, the powder is transferred into a vacuum furnace and heat-treated at 350~450℃ for 30~120min to obtain a lightweight microsphere-supported titanium dioxide film material.

[0025] From the appendix Figure 1 As can be seen, the lightweight microsphere-supported titanium dioxide film material prepared by Example 1 of the present invention has a typical core-shell structure. The titanium dioxide film is uniformly covered on the surface of the lightweight microspheres. The core-shell structure of the coating greatly improves the specific surface area of ​​the material, thereby making the prepared powder have higher photocatalytic performance.

[0026] like Figure 2As shown, the powder spraying coating apparatus used in Embodiments 1 and 2 above includes a spraying coating chamber 1. The upper part of the spraying coating chamber 1 is a cylindrical chamber with a material feeding port 11 and a spraying port 12 on the top surface. The lower part is a conical chamber with a blower inlet 2 on the side wall and an opening with a filter valve 31 at the bottom of the conical chamber. A spraying liquid filter membrane 4 is detachably sealed at the top of the opening, and a spraying liquid collection container 3 is connected to the bottom of the opening. The spraying port 12 is used to insert the coating spray gun; the blower inlet 2 is used to connect to an external blower; the spraying liquid filter membrane 4 is a common filter membrane, which is removed and replaced after coating is completed.

[0027] like Figure 3 and Figure 4 As shown, the blower inlet 2 is inclined downward at 45° to the vertical direction, and there is one blower inlet 2 on each side of the spray coating chamber 1, which are distributed in a rotationally symmetrical or axisily symmetrical manner with the spray coating chamber 1 as the center of symmetry.

[0028] The aforementioned powder coating device has a blower inlet 2, angled downwards at 45° to the vertical, on each side of the lower conical chamber of the coating chamber 1, and the two are symmetrically distributed. When the blower starts, the two downward airflows converge in the conical chamber and form a rotating upward airflow; the lightweight microspheres are lifted and dispersed by this airflow, forming a highly turbulent suspension state in the cylindrical chamber; the lightweight microspheres tumble violently in the airflow, achieving full separation between individuals; at this time, the titanium dioxide sol droplets sprayed from the top spray nozzle 12 can fully collide and adhere to the surface of the lightweight microspheres. This dynamic spraying mode ensures that the sol forms a relatively complete and uniform coating layer on the surface of the lightweight microspheres, avoiding the problem of lightweight microspheres sticking together and clumping due to wetting.

[0029] The powder coating device has an opening with a filtrate valve 31 at the bottom of the lower conical chamber, and a spray liquid filter membrane 4 is detachably sealed at the top of the opening. During or after the spraying process, residual droplets will flow downwards along the inner wall of the chamber under gravity. The spray liquid filter membrane 4 allows the liquid to pass through, thereby achieving solid-liquid separation. The liquid is discharged through the filtrate valve 31 and recovered using the spray liquid collection container 3. This not only improves the utilization rate of the sol and reduces raw material costs, but also prevents residual liquid from accumulating at the bottom of the chamber or in the microsphere layer, avoiding the immersion or secondary agglomeration of the coated lightweight microspheres, thus ensuring the stability of the coating process and the uniformity of the composite powder quality.

[0030] This powder coating device adopts a cavity structure with an upper cylindrical and lower conical shape. The top is equipped with independent feeding and discharging ports 11 and spraying ports 12. The cylindrical upper cavity provides ample space for the fluidization and spraying of lightweight microspheres, while the conical lower cavity facilitates the formation of a stable, converging airflow field, promoting the circulation of lightweight microspheres and liquid aggregation. For residual liquid that may adhere to the inner wall of the cavity after spraying and cannot be blown away by the airflow, this structure allows it to flow naturally down to the bottom of the cone, where it is ultimately filtered through a spray liquid filter membrane, ensuring the cleanliness of the cavity and reducing cross-contamination between batches.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material, characterized in that... The method includes the following steps: Step S1: Mix titanium source, alcohol solvent, water and acid catalyst, and form titanium oxide sol through hydrolysis and condensation reaction; Step S2: Provide lightweight microspheres; Step S3: Using a powder spraying coating device, the titanium dioxide sol is sprayed onto the surface of the lightweight microspheres, so that the titanium dioxide sol adheres to the surface of the lightweight microspheres, forming a wet composite powder; Step S4: The wet composite powder is dried and heat-treated to obtain a lightweight microsphere-supported titanium dioxide film material.

2. The method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material according to claim 1, characterized in that... In step S1, the preparation of the titanium dioxide sol further includes adding a complexing agent and a leveling agent.

3. The method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material according to claim 2, characterized in that... Step S1 involves mixing an appropriate amount of ethanol and acetylacetone, adding tetrabutyl titanate, stirring evenly in a water bath at 30-60°C, adjusting the pH of the mixture to 3-6 with concentrated HCl, adding deionized water, stirring for 1-3 hours, and then adding N,N-dimethylformamide to obtain titanium dioxide sol.

4. The method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material according to claim 3, characterized in that... The molar ratio of deionized water to tetrabutyl titanate is 1:1 to 9:1, and the titanium dioxide solid content of the system is 0.5 to 10 wt%.

5. The method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material according to claim 3, characterized in that... The ethanol mentioned is anhydrous ethanol.

6. The method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material according to claim 1, characterized in that... Step S4 involves collecting the wet composite powder and spray-drying it or transferring it into a vacuum drying oven. The powder is dried at 50-150°C for 30-60 minutes, and then transferred to a vacuum furnace for heat treatment at 350-450°C for 30-120 minutes to obtain a lightweight microsphere-supported titanium dioxide film material.

7. The method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material according to claim 1, characterized in that... The lightweight microspheres are hollow glass microspheres or fly ash cenospheres.

8. The method for preparing a core-shell structured lightweight microsphere-supported titanium dioxide film material according to claim 7, characterized in that... The diameter of the hollow glass microspheres or fly ash cenospheres is 50 nm to 50 μm.

9. A powder spraying coating apparatus as described in claim 1, characterized in that... The device includes a spray coating chamber. The upper part of the spray coating chamber is a cylindrical chamber with a material feeding port and a spraying port on the top surface. The lower part is a conical chamber with a blower inlet on the side wall and an opening with a filter valve at the bottom of the conical chamber. A spray liquid filter membrane is detachably sealed at the top of the opening, and a spray liquid collection container is connected to the bottom of the opening.

10. A powder spraying coating apparatus as described in claim 9, characterized in that... The blower inlet is angled downwards at 45° to the vertical direction, and one blower inlet is set on each side of the spray coating chamber, which are distributed in a rotationally symmetrical or axisily symmetrical distribution with the spray coating chamber as the center of symmetry.

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